HK1220371B - Quinone based nitric oxide donating compounds for ophthalmic use - Google Patents

Description

Quinone-based nitric oxide donor compounds for ophthalmic applications

The present invention relates to nitric oxide donor compounds of formula (I) and their use for the treatment and/or prevention of glaucoma and ocular hypertension.

The invention also relates to a combination comprising a nitric oxide donor compound of formula (I) and one or more other active ingredients for the treatment and/or prevention of glaucoma and ocular hypertension.

Glaucoma, including normal tension glaucoma and high tension glaucoma, is an ocular disease characterized by a gradual loss of visual field due to irreversible optic nerve damage, which, if left untreated, can lead to complete blindness. Ocular hypertension glaucoma occurs when an imbalance in the production and removal of fluid (aqueous humor) from the eye increases the intraocular pressure to unhealthy levels.

In contrast, normal tension glaucoma occurs despite intraocular pressure remaining at reasonably low levels.

In one form of Primary Open Angle Glaucoma (POAG), loss of visual field is associated with a persistent increase in intraocular pressure in the affected eye. Furthermore, elevated intraocular pressure without visual field loss is considered to be a sign of the early stages of this form of POAG.

Normal tension glaucoma is a chronic progressive optic neuropathy that results in typical optic nerve head changes, retinal nerve fiber layer defects, and characteristic visual field defects. Furthermore, the anterior chamber angle is open and intraocular pressure values are within statistically normal limits (below 22mmHg) (Lee et al, 1998; for review see Hoyng and Kitazawa 2002).

There is evidence that treatment of normal tension glaucoma by lowering intraocular pressure slows the progression of glaucoma. At least a 30% reduction in intraocular pressure is required to cause a favorable change in this disease.

In addition to these two major types of glaucoma, other diseases can also lead to elevated intraocular pressure, i.e., secondary glaucoma, including post-uveitis glaucoma and steroid glaucoma.

Glaucoma treatment in the prior art consists in lowering intraocular pressure by administering drugs which reduce the production of aqueous humor in the eye or increase fluid drainage, such as beta blockers, alpha agonists, cholinergic agents, carbonic anhydrase inhibitors or prostaglandin analogues.

Conventional drugs for the treatment of glaucoma have various side effects.

Topical beta blockers exhibit severe pulmonary side effects, depression, fatigue, confusion, impotence, hair loss, heart failure and bradycardia.

Local alpha receptor agonists have a relatively high incidence of allergic or toxic reactions; topical cholinergics (miotics) can cause visual side effects.

Side effects associated with oral carbonic anhydrase inhibitors include fatigue, anorexia, depression, paresthesia, and abnormal serum electrolytes (The Merck Manual of Diagnosis and Therapy, 17 th edition, ed. by m.h. beers and r.berkow, sec.8, ch.100).

Finally, topical prostaglandin analogs (bimatoprost, latanoprost, travoprost, tafluprost and unoprostone) used to treat glaucoma can produce side effects on the eye such as increased pigmentation of the iris, eye irritation, conjunctival congestion, iritis, uveitis and macular edema (Martindale, 33 th edition, p.1445).

Macular diseases, such as age-related macular degeneration and diabetic macular edema, are the leading causes of blindness. The drugs currently used to treat macular disease are steroidal anti-inflammatory drugs such as triamcinolone acetonide or fluocinolone acetonide. However, intravitreal injection of triamcinolone acetonide is associated with a variety of ocular complications, including elevated intraocular pressure.

Increased intraocular pressure is a common postoperative complication after eye surgery such as vitrectomy, vitreoretinal surgery, retinal detachment surgery, and panretinal photocoagulation.

It is well known that intraocular Nitric Oxide (NO) plays an important role in certain physiological processes such as regulation of aqueous humor dynamics, vascular tone, retinal neurotransmission, apoptosis of retinal ganglion cells, light conduction and ocular immune response, and on the other hand, overproduction of NO is associated with many ocular diseases.

Us patent 4590207 discloses an ophthalmic solution comprising isosorbide mononitrate as an active ingredient for the treatment and/or prevention of intraocular hypertension and glaucoma.

U.S. patent application 2002/0168424 discloses the use of a mixture of a Nitric Oxide (NO) donor such as a nitrovasodilator such as minoxidil, nitroglycerin, L-arginine, isosorbide dinitrate or a nitroprusside salt with an inhibitor of cyclic guanosine 3 ', 5' -monophosphate (cGMP) specific phosphodiesterase type 5 (PDE5) such as sildenafil citrate for the treatment of glaucoma or ocular hypertension. The disclosed combinations can promote systemic vasodilation, increased optic nerve blood flow, dilation of the tissue of the trabecular meshwork, schlemm's canal, and uveoscleral outflow tract, increased aqueous humor drainage, thereby lowering intraocular pressure (IOP) of the mammalian eye.

Organic nitrates have been used for over a century to treat heart disease, however, classical organic nitrates for therapeutic use such as nitroglycerin, isosorbide dinitrate, or isosorbide 5-mononitrate are known to be tolerated and lose their activity upon repeated administration. Nitrate tolerance still occurs even with elevated drug plasma concentrations, reflecting a decrease in vascular sensitivity to previous therapeutic levels. This can be prevented or reduced by including a nitrate withdrawal period in the dosing regimen.

British patent application No. GB 2349385 a discloses the use of antioxidants nitrates or nitrites as vasodilators for the treatment of pathologies associated with vascular endothelial dysfunction, in particular heart diseases.

The disclosed compounds contain a superoxide scavenger moiety and a nitrate or nitrite group, and the two moieties are stably linked to reduce molecular degradation under physiological conditions. The stable linkage increases the activity of the antioxidant scavenger, thereby avoiding reactive oxygen-mediated NO depletion that further generates harmful substances.

Accordingly, the technical problem to be solved by the present invention is to provide an effective therapeutic agent for the treatment and/or prevention of high-tension glaucoma, normal-tension glaucoma, secondary glaucoma and ocular hypertension.

Surprisingly, it has now been found that the nitric oxide donor of the present invention can lower intraocular pressure and appear significantly less tolerant than the nitric oxide donors described in the prior art.

It has also surprisingly been found that the nitric oxide donor of the present invention additionally has beneficial anti-inflammatory and antioxidant properties that, in conjunction with the delivery of nitric oxide, play a role in promoting regulation, cellular repair and protection of aqueous humor outflow through the trabecular meshwork.

The present invention relates to compounds of formula (I) or stereoisomers thereof.

The invention relates to compounds of formula (I)

Or a stereoisomer thereof, wherein:

R₁selected from H, methyl, methoxy;

R₂is H or methyl;

R₃selected from H, methyl, methoxy;

or R₁And R₃Together form-CH ═ CH-;

R₄and R₅Is methyl and n is 1, or

R₄Is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁selected from H, methyl, methoxy;

R₂is methyl;

R₃selected from H, methyl, methoxy;

or R₁And R₃Together form-CH ═ CH-;

R₄and R₅Is a methyl group and n is 1,

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁selected from H, methyl, methoxy;

R₂is methyl;

R₃selected from H, methyl, methoxy;

or R₁And R₃Together form-CH ═ CH-;

R₄and R₅Is a methyl group and n is 1,

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁selected from H, methyl, methoxy;

R₂is methyl;

R₃selected from H, methyl, methoxy;

or R₁And R₃Together form-CH ═ CH-;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁selected from H, methyl, methoxy;

R₂is methyl;

R₃selected from H, methyl, methoxy;

or R₁And R₃Together form-CH ═ CH-;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁selected from H, methyl, methoxy;

R₂is methyl;

R₃selected from H, methyl, methoxy;

or R₁And R₃Together form-CH ═ CH-;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 1 and R₆Is H or methyl, preferably R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁、R₂and R₃Is methyl;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁、R₂and R₃Is methyl;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁、R₂、R₃is methyl;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) or a stereoisomer thereof, wherein:

R₁、R₂、R₃is methyl;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is a methoxy group;

R₂is methyl;

R₃is a methoxy group;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is a methoxy group;

R₂is methyl;

R₃is a methoxy group;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is a methoxy group;

R₂is methyl;

R₃is a methoxy group;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is a methoxy group;

R₂is methyl;

R₃is a methoxy group;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) or a stereoisomer thereof, wherein:

R₂is methyl;

R₁and R₃Together form-CH ═ CH-;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₂is methyl;

R₁and R₃Together form-CH＝CH-CH＝CH-；

R₄And R₅Is methyl and n is 1;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₂is methyl;

R₁and R₃Together form-CH ═ CH-;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₂is methyl;

R₁and R₃Together form-CH ═ CH-;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is methyl;

R₂is methyl;

R₃is a methoxy group;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 10, preferably m is an integer from 1 to, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is methyl;

R₂is methyl;

R₃is a methoxy group;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is methyl;

R₂is methyl;

R₃is a methoxy group;

R₄is H, R₅Selected from phenyl, p-fluorophenyl and p-methylOxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is methyl;

R₂is methyl;

R₃is a methoxy group;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is a methoxy group;

R₂is methyl;

R₃is methyl;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is a methoxy group;

R₂is methyl;

R₃is methyl;

R₄and R₅Is methyl and n is 1;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is a methoxy group;

R₂is methyl;

R₃is methyl;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 or 1;

R₆is H or methyl.

Another embodiment of the present invention provides a compound of formula (I) as defined above or a stereoisomer thereof, wherein:

R₁is a methoxy group;

R₂is methyl;

R₃is methyl;

R₄is H, R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl and n is 2;

m is an integer from 1 to 10, preferably m is an integer from 1 to 6, most preferably 4 or 6;

p is 0 and R₆Is H.

Another embodiment of the present invention provides a compound of formula (I) selected from the group consisting of:

and stereoisomers thereof.

Another embodiment of the present invention provides the use of a compound of formula (I) for the treatment of ocular hypertension glaucoma, normal tension glaucoma, secondary glaucoma and ocular hypertension.

The tests carried out demonstrated that the compounds of formula (I) exhibit antioxidant activity comparable to that of the well-known antioxidant compounds such as ferulic acid and caffeic acid or edaravone.

Furthermore, the compounds of the invention significantly attenuated saline-induced intraocular pressure (IOP) increases in a transient ocular hypertension in vivo model in rabbits.

Thus, the compounds of the present invention are useful as medicaments for the prevention and/or treatment of ophthalmic diseases in which the absence of NO and oxidative stress play an important role in their pathogenesis.

Another embodiment of the present invention relates to compounds of formula (I) for use in the treatment and/or prevention of hypertensive glaucoma, normotensive glaucoma, secondary glaucoma and ocular hypertension.

Another embodiment of the present invention relates to compounds of formula (I) for use in the treatment of ocular hypertension caused by orbital edema, postoperative complications, intraocular inflammation, pupil obstruction, or idiopathic causes.

Furthermore, the present invention relates to compounds of formula (I) for use in the treatment and/or prevention of age-related macular degeneration, diabetic retinopathy, retinal vein occlusion, macular degeneration, inflammatory retinopathies, uveitis.

The present invention also relates to a composition comprising a nitric oxide donor of formula (I) in combination with one or more other active ingredients selected from the group consisting of: alpha adrenergic receptor agonists, beta receptor blockers, carbonic anhydrase inhibitors, prostaglandin analogs, non-steroidal anti-inflammatory drugs, steroidal anti-inflammatory drugs.

Examples of suitable alpha adrenergic receptor agonists are brimonidine, alcolonine, clonidine.

Examples of suitable beta blockers are timolol, carteolol, betaxolol, levobunolol.

Examples of suitable carbonic anhydrase inhibitors are dorzolamide, acetazolamide, brinzolamide, dorzolamide, diclofenamide, methazolamide.

Examples of suitable prostaglandin analogs are bimatoprost, latanoprost, travoprost, unoprostone and tafluprost.

Examples of non-steroidal anti-inflammatory drugs are bromfenac, flurbiprofen, naproxen, ketoprofen.

Examples of steroidal anti-inflammatory drugs are dexamethasone, fluocinonide, triamcinolone acetonide, budesonide, prednisolone.

Another embodiment of the present invention is the composition as described above for use in the treatment and/or prevention of hypertensive glaucoma, normotensive glaucoma, secondary glaucoma and ocular hypertension.

Another embodiment of the present invention is a composition as described above for use in the treatment and/or prevention of secondary glaucoma, age-related macular degeneration, diabetic retinopathy, macular degeneration, inflammatory retinopathy, uveitis.

Another embodiment of the invention is a composition as described above for use in treating high ocular pressure caused by orbital edema, postoperative complications, intraocular inflammation, pupil obstruction, or idiopathic causes.

Another embodiment of the present invention provides a pharmaceutical formulation comprising at least one nitric oxide donor of formula (I) and at least one ophthalmologically acceptable component and/or an ophthalmologically acceptable carrier for topical, periocular or intraocular administration.

Another embodiment of the present invention provides a pharmaceutical formulation for topical, periocular or intraocular administration comprising at least one nitric oxide donor of formula (I) and one or more additional active ingredients selected from the group consisting of alpha adrenergic receptor agonists, beta receptor blockers, carbonic anhydrase inhibitors, prostaglandin analogs, non-steroidal anti-inflammatory drugs, and at least one ophthalmologically acceptable ingredient and/or an ophthalmologically acceptable carrier.

Preferred routes of administration for the compounds and compositions of the invention are topical or intravitreal. The compounds and compositions of the present invention may be applied topically in the form of solutions, suspensions or emulsions (dispersions).

The compounds for use in the present invention may also be administered periocularly, and may be formulated as solutions or suspensions for periocular administration. Formulations for periocular administration are typically periocular injections or surgical irrigating solutions. Periocular administration refers to administration to tissue near the eye, for example, to the periocular tissue or space within the orbit. Periocular administration may be by injection, deposition, or any other placement.

The compounds and compositions of the present invention may be formulated as solutions or suspensions for intraocular administration. Compositions for intraocular administration are typically intraocular injection compositions or surgical irrigation fluids.

By "ophthalmically acceptable" component is meant a component that does not cause any significant ocular injury or ocular discomfort at the concentrations and for the time of its intended use. The solubilizers and stabilizers should be non-reactive. By "ophthalmically acceptable" carrier is meant any substance or combination of substances that does not react with the compound and is suitable for administration to a patient.

The nitric oxide donors of the present invention are typically included in the topical, periocular or intraocular formulations described herein in an amount of from about 0.001 to about 10.0% weight/volume. A preferred concentration range is from about 0.1 to about 5.0% w/v.

General synthetic methods

Wherein R is₁、R₂、R₃、R₆M and p are as defined above, R₄And R₅Compounds of formula (I) which are methyl and n is 1 may be prepared by:

as shown in scheme 1, compound (Va) is reacted with a compound wherein R₆M and p are as defined above in a coupling reagent such as DCC, EDC, HBTU, HATU and catalytic amounts of DMAP or Sc (OTf)₃In the presence of an aprotic/nonpolar solvent such as THF, DMF or CH₂Cl₂At a temperature of-80 ℃ to 60 ℃; or

Wherein Xa is selected from N as shown in scheme 1₃F, Cl, Br or a group of the formula (Xaa) or (Xbb)A chemical group, preferably Cl or (Xaa), of a compound of formula (Vb)

With compounds (VI) in the presence of a base such as DMAP, pyridine or triethylamine or K₂CO₃、Cs₂CO₃In the presence of an aprotic/nonpolar solvent such as THF, DMF or CH₂Cl₂At a temperature of-80 ℃ to 60 ℃:

the compound of formula (Vb) can be prepared from the corresponding compound of formula (Va) by known methods. Compounds of formula (Va) can generally be prepared as shown in scheme 2 by the methods described in Carpino et al, J.org.chem.,1989,54, 3303-one 3310.

The hydroquinone of formula (III) is reacted with methanesulfonic acid and methyl-3-methylbut-2-enoate to give the lactone (IV) as described in Carpino et al, J.org.chem.,1989,54, 3303-one 3310.

The compounds of formula (Va) are prepared by reacting compound (IV) with an oxidizing agent such as NBS or PDC as new crystals, according to the conditions described by Borchardt et al, J.Am.chem.Soc.,1972,94,9175 and Carpino et al, J.Org.chem.,1989,54, 3303-.

Compounds of formula (III) are commercially available or may be prepared by reacting the corresponding quinone of formula (II) with a reducing agent such as NaBH₄Reduced in methanol to prepare (scheme 3).

The quinones of formula (II) are commercially available or can be prepared by methods described in the literature.

Wherein m, p and R₆The compounds of the formula (VI) as defined above are known from the literature or can be prepared starting from the corresponding alcohols of the formula (VIIa)

Wherein PG is a suitable hydroxy protecting group, preferably an ester such as benzoate, and m, p and R₆As defined above, by reaction with nitric acid and acetic anhydride at a temperature in the range of-50 ℃ to 20 ℃, or by reaction with trifluoromethanesulfonic anhydride/tetraalkylammonium nitrate salt in an aprotic polar/nonpolar solvent such as DMF, THF or CH₂Cl₂In the presence of a base such as pyridine, lutidine, 2, 6-di-tert-butyl-4-methylpyridine at a temperature in the range of-80 ℃ to 65 ℃ and then removing the protecting group by known methods (see, for example, T.W.Greene, P.G.M.Wuts "Protective groups in organic Synthesis", 4 th edition, J.Wiley&Sons, New York, 2006).

Alternatively, the hydroxyl group of (VIIa) may be first converted to the corresponding mesyl or tosyl or triflate group, then nitrated using known methods, for example tetraalkylammonium nitrate and sodium nitrate, and the protecting group removed by methods known in the art.

Or, wherein m and R₆Compounds of formula (VI) as defined above, p being 0, may be prepared by reacting the corresponding halogen derivative (VIIb) wherein Q is H or PG (wherein PG is as previously defined) and X is a halogen atom, e.g. Cl, Br, I, with a nitrating agent, e.g. AgNO₃In acetonitrile according to known literature methods, followed by the removal of the Q protecting group (if present) by methods known in the art.

Wherein m is as previously defined, p is 1 and R₆Is H or CH₃The compound of formula (VIIa) can be prepared by reacting the corresponding alkenyl alcohol of formula (VIIIb) with a dihydroxylation reagent such as ADmix α or ADmix β or KMnO₄、OsO₄Protic/aprotic solvents at 1/1, e.g. tBuOH, H₂O, optionally in the presence of an activator such as methanesulfonamide, at a temperature in the range from-20 to 30 ℃, and optionally followed by chiral separation of the diol (VIIa)

Compounds of formula (VIIIb) are prepared from compound (VIIIa) by protecting the free hydroxy group with the appropriate PG group as defined above using known methods (see, e.g., t.w.greene, p.g.m.wuts "Protective groups in organic Synthesis", 4 th edition, j.wiley & Sons, New York, 2006).

Compound (VIIIa) is commercially available or can be prepared from known compounds using known methods.

Or, wherein m is as defined above, p is 1 and R₆Compound (VI) which is H can be prepared by reacting compound (VIIIb) with I₂And AgNO₃Prepared by carrying out the reaction as described in the literature in acetonitrile (see Cena, C. et al, Bioorganic&Medicinal Chemistry 2008,16,5199–5206)。

Or, wherein m is as defined above, p is 1 and R₆Is CH₃Compound (VI) of (VI) can be obtained from compound (VIIa) as shown in scheme 4, by the following steps:

1) protecting the primary hydroxyl group of Compound (VIIa)

2) Protection of the secondary hydroxyl group to give a compound of formula (X), wherein PG₁Is triphenylmethyl and PG₂Is TBDPS, TBDMS or TIPS.

3) Removal of the protecting group PG₁And oxidizing the compound (XI) into an aldehyde by a known method to obtain a compound (XII)

4) The compound (XII) is reacted with the compound (XIII) in the presence of a chiral amino alcohol catalyst such as (1S,2R) - (-) - (dibutylamino) -1-phenyl-1-propanol or (1R,2S) - (+) - (dibutylamino) -1-phenyl-1-propanol or a achiral catalyst in an aprotic/nonpolar solvent such as toluene, THF or Et₂In O at a temperature of-80 ℃ to 65 DEG C

CH₃-D-Z₂

(XIII)

Wherein D is Zn, Mg or Cu, preferably Zn; z is R or halogen, preferably Cl

5) Removal of the protecting group PG by methods known in the art₂Compound (VI) is obtained.

Wherein R is₄Is H and R₅Selected from phenyl, p-fluorophenyl, p-methoxyphenyl, p-isopropylphenyl, p-trifluoromethylphenyl and p-methylphenyl, n is 2 and R₁、R₂、R₃、R₆Compounds of formula (I) wherein m and p are as defined above may be prepared by:

as shown in scheme 5, R therein is₁、R₂、R₃As defined above, R₈Is H, F, CH₃O-、(CH₃)₂CH-、CF₃-or CH₃The compound of formula (XVIIIa) with the compound of formula (VI) as defined above in a coupling reagent such as DCC, EDC, HBTU, HATU and a catalytic amount of Sc (OTf)₃Or in the presence of DMAP;

as shown in scheme 5, R therein is₁、R₂、R₃、R₈And Xa is as defined above with a compound of the formula (XVIIb) and a compound of the formula (VI) in a base such as DMAP, pyridine or triethylamine or K₂CO₃、Cs₂CO₃In the presence of an aprotic/nonpolar solvent such as THF, DMF or CH₂Cl₂At a temperature of-80 ℃ to 60 ℃ in the presence of:

the compounds of the formula (XVIIb) can be prepared in a known manner from the corresponding compounds of the formula (XVIIa).

The compound of formula (XVIIIa) can be prepared by reacting a carboxylic acid of formula (XVII) (wherein R is₁、R₂、R₃And R₈As described above) was prepared by oxidation according to the method disclosed in Jurd and Wong, aust.j.chem.1980,33,137, as shown in scheme 6.

The carboxylic acids of formula (XVII) may be prepared by an acid-catalyzed coupling reaction between hydroquinone (III) and a commercially available gamma-lactone (XVI)

Example 1

Synthesis of 4- (nitrooxy) butyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 1)

Step 1 Synthesis of 6-hydroxy-4, 4,5,7, 8-pentamethylbenzodihydropyran-2-one

A synthetic method similar to that described in Carpino et al, J.org.chem.,1989,54, 3303-one 3310 was used.

Methanesulfonic acid (20mL) was heated at 70 ℃.2, 3, 5-trimethylbenzene-1, 4-diol (2.0g,13.14mmol) and methyl 3-methylbut-2-enoate (1.94mL,13.14mmol,1eq) were added rapidly at the same time and the reaction was heated at this temperature for 2 hours. The reaction was then poured into water and, after cooling, extracted with EtOAc (3 × 100 mL). The combined organic layers were washed with water, saturated NaHCO in sequence₃Washed with water and brine, dried (Na)₂SO₄) Filtered and evaporated. The residue was taken up in 30% CHCl₃The n-hexane solution of (1.86g, yield: 60%) gave the title compound as a light gray solid. Melting point 185 ℃.

¹H NMR(300MHz,CDCl₃)4.63(s,1H),2.54(s,2H),2.36(s,3H),2.22(s,3H),2.18(s,3H),1.45(s,6H)。

Step 2 Synthesis of 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dien-1-yl) butanoic acid (intermediate 2)

The reaction was carried out according to the conditions described by Borchardt et al, J.am.chem.Soc.,1972,94, 9175.

To a stirred solution of 6-hydroxy-4, 4,5,7, 8-pentamethylbenzodihydropyran-2-one (2.0g,0.853mmol) in 10% acetonitrile in water (100mL) was added a solution of freshly recrystallized NBS (1.6g,0.853mmol,1eq) in acetonitrile (20 mL). The reaction was stirred for 1 hour then diluted with water (100mL) and Et₂O (3X100 mL). The combined organic layers were washed with water and brine and dried (Na)₂SO₄) Filtered and evaporated. The residue was taken up in Et₂Crystallization from n-hexane gave the title compound as a yellow solid (1.64g, yield: 77%).

¹H NMR(300MHz,CDCl₃)11.08–8.78(m,1H),3.02(s,2H),2.14(s,3H),1.95(s,3H),1.93(s,3H),1.44(s,6H)。

Step 3-Synthesis of 4-hydroxybutyl-4-nitrobenzoate

To a stirred solution of 1, 4-butanediol (3.0g,33.29mmol,1.1eq) and 4-nitrobenzoyl chloride (5.56g,29.96mmol) in EtOAc (100mL) cooled to 0 deg.C was added triethylamine (4.6mL,33.3mmol,1.1eq) dropwise and the reaction was stirred vigorously for 6 hours. The reaction was diluted with water, the organic layer was separated and washed with HCl 0.1M, water and salt. The organic phase was dried (Na)₂SO₄) Filtered and evaporated. The residue was taken up in cold Et₂Grind in O and filter off the solid. The filtrate was evaporated to give the title compound as a viscous oil which solidified upon standing (2.86g, yield: 40%).

¹H NMR(300MHz,CDCl₃)8.30(d,J＝8.8,2H),8.22(d,J＝8.8,2H),4.44(t,J＝6.5,2H),3.76(t,J＝6.3,2H),1.93(dt,J＝14.4,6.7,2H),1.75(dt,J＝13.2,6.4,2H).

Step 4 Synthesis of 4- (nitrooxy) butyl 4-nitrobenzoate

Concentrated nitric acid (1.9mL,45.15mmol,3eq) was added dropwise to acetic anhydride (20mL) cooled to 0 ℃. Solid 4-hydroxybutyl 4-nitrobenzoate was then added and the reaction stirred at this temperature for 30 minutes and then poured onto ice. After thawing, the organic oil is separated from the aqueous liquid anddilute with ethyl acetate. The organic layer was washed with NaHCO₃(2X 30mL), water and brine, dried (Na)₂SO₄) Filtered and evaporated. The residue was purified by flash chromatography (Biotage System, SNAP Cartridge silica 100g, eluent: n-hexane/ethyl acetate 85/15 to n-hexane/ethyl acetate 75/25 in 8 Column Volumes (CV)) to give the title compound as a yellow oil (3.73g, yield: 87%).

¹H NMR(300MHz,CDCl₃)8.34–8.29(m,2H),8.24–8.19(m,2H),4.56(t,J＝5.9,2H),4.44(t,J＝6.0,2H),1.99–1.90(m,4H)。

Step 5 Synthesis of 4-hydroxybutyl nitrate

To a stirred solution of 4- (nitrooxy) butyl 4-nitrobenzoate (2.13g,7.49mmol) in 3/1 THF/EtOH mixture (40mL) cooled to 0 deg.C was added NaOH 1M (7.5mL,1 eq). The reaction was stirred at this temperature for 3 hours and then diluted with EtOAc and water. The organic layer was separated, washed with water and brine, dried (Na)₂SO₄) Filtered and evaporated. The residue was purified by flash chromatography (Biotage System, SNAP Cartridge silica 100g, eluent: n-hexane/ethyl acetate 85/15 to n-hexane/ethyl acetate 75/25 in 8 column volumes) to give the title compound (0.48g, yield: 49%) as a colorless oil.

¹H NMR(300MHz,CDCl₃)4.52(t,J＝6.5,2H),3.72(t,J＝6.2,2H),1.87(dt,J＝14.2,6.5,2H),1.75–1.63(m,1H)。

Step 6 Synthesis of 4- (nitrooxy) butyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 1)

To a stirred mixture of 4-hydroxybutyl nitrate (prepared in step 5) (2.0g,14.8mmol) and 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) cooled to 0 deg.C) Butyric acid (prepared in step 2) (3.70g,14.8mmol) in dry CH₂Cl₂EDC (3.12g,16.28mmol,1.1eq) and a catalytic amount of DMAP (0.05g) were added to the solution in (1). The reaction was stirred at this temperature for 5 hours then washed with water, HCl 1M, water and brine, dried (Na)₂SO₄) Filtered and evaporated. The residue was purified by flash chromatography (Biotage system, 2SNAP cartridge silica 340g, eluent: n-hexane/ethyl acetate 85/15 to n-hexane/ethyl acetate 70/30 in 8 column volumes) to give the title compound as a yellow oil (5.02g, yield: 92%).

¹H NMR(300MHz,CDCl₃)4.45(t,J＝6.2,2H),4.01(t,J＝6.1,2H),2.98(s,2H),2.14(s,3H),1.94(s,6H),1.82–1.62(m,4H),1.42(s,6H)。

Example 2

Synthesis of 6- (nitrooxy) hexyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 2)

Step 1 Synthesis of 6-Nitroxy-hex-1-ol

To 6-bromohex-1-ol (2.2mL,16.6mmol) in CH₃CN (100mL) solution was added silver nitrate (5.95g,35mmol,2 eq). The reaction solution was stirred at room temperature for 3 days. The reaction was stopped by adding an aqueous salt solution. After stirring for 15 minutes, the solution was filtered, extracted with ethyl acetate and washed with H₂O, washed with brine, dried over sodium sulfate, filtered and evaporated. The residue is purified by column chromatography (Biotage System, SNAP Cartridge silica 100g, eluent: n-hexane/ethyl acetate 80/20 to n-hexane in 12 column volumesEthyl acetate 50/50) gave the desired product as a colorless oil (2.34g, yield: 86%).

¹H NMR(300MHz,CDCl₃)4.47(t,J＝6.6Hz,2H),3.68(t,J＝6.1Hz,2H),1.77(m,2H),1.62(m,2H),1.48(m,4H),1.27(s,1H)。

Step 2 Synthesis of 6- (nitrooxy) hexyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate

To a stirred solution of 6-hydroxyhexylnitrate (164mg,1.0mmol) and 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) butanoic acid (prepared in example 1, step 2) (250mg,1.0mmol) dried CH cooled to 0 deg.C₂Cl₂EDC (202mg,1.1mmol,1.1eq) and catalytic amounts of DMAP (0.02g) were added to the solution. The reaction mixture was stirred from 0 ℃ to room temperature for 16 hours. The reaction mixture was washed with water, HCl 1M, water and brine, dried (Na)₂SO₄) Filtered and evaporated. The residue was purified by flash chromatography (Biotage System, SNAP Cartridge silica 100g, eluent: n-hexane/ethyl acetate 85/15 to n-hexane/ethyl acetate 70/30 in 8 column volumes) to give the title compound (286mg, yield: 72%) as a yellow oil.

¹H NMR(300MHz,CDCl₃)4.44(t,J＝6.6,2H),3.97(t,J＝6.6,2H),2.97(s,2H),2.12(s,3H),1.94(d,J＝10.4,6H),1.77–1.65(m,2H),1.63–1.50(m,2H),1.47–1.41(m,6H),1.41–1.30(m,4H)。

Example 3

Synthesis of 6- (nitrooxy) hexyl 4-phenyl-4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 3)

Step 1 Synthesis of 4- (2, 5-dihydroxy-3, 4, 6-trimethylphenyl) -4-phenylbutyric acid

The reaction was carried out according to the conditions described in Mitsuru et al, J.Med.chem.Soc.,1989,32, 2214-one 2221.

Boron trifluoride etherate (0.25 ml; 1.99mmol) was added dropwise at 60 ℃ over the course of 10 minutes to a mixture of trimethylhydroquinone (1.0 g; 6.57mmol) and gamma-phenyl-gamma-butyrolactone (1.1 g; 6.57mmol) in toluene (70 ml). The mixture was stirred for an additional 2 hours, then the solvent was evaporated under reduced pressure. The residue was purified by flash chromatography (Biotage System, SNAP cartridge silica 100g, from 9% to 60% EtOAc in n-hexane over 10 column volumes) to afford the title compound as an orange solid (0.74 g; yield: 36%).

¹H NMR(300MHz,CDCl₃)7.39–7.07(m,5H),4.72–4.25(m,3H),2.74–2.25(m,4H),2.25(s,3H),2.08(s,3H),1.98(m,2H)。

Step 2 Synthesis of 4-phenyl-4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dien-1-yl) butanoic acid

To 4- (2, 5-dihydroxy-3, 4, 6-trimethylphenyl) -4-phenylbutyric acid (0.74 g; 2.33mmol) in CH₃CN:H₂To a solution of O1: 1(50ml) was added cerium ammonium nitrate (3.3 g; 5.87 mmol). The mixture was stirred at room temperature for 3 hours, then poured into H₂O (30 ml). Et was added₂O (20ml), the two phases were separated and the organic layer was washed with Et₂O (2X20 ml). The combined organic layers were washed with brine, washed with Na₂SO₄Drying and concentration gave 560mg of the title compound without further purification.¹H NMR(300MHz,CDCl₃)7.40–7.06(m,5H),4.35(t,J＝7.6,1H),2.77–2.25(m,4H),2.15–2.03(m,3H),1.97(m,6H)。

Step 3 Synthesis of 6- (nitrooxy) hexyl 4-phenyl-4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound (3))

To 4-phenyl-4- (2,4, 5-trimethyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) butanoic acid (0.29 g; 0.92mmol) and 6-nitrooxy-hex-1-ol (synthesized in example 2, step 1) (0.17 mg; 0.92mmol) in CH₂Cl₂To a solution in (5ml) was added 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC) (0.29 g; 1.38mmol) and a catalytic amount of DMAP. The solution was stirred at 0 ℃ for 30 minutes and at room temperature for 4 hours, then with NaH₂PO₄5％(5ml)、H₂O (5ml) and brine. The organic layer was washed with Na₂SO₄Dried and concentrated under reduced pressure. The residue was purified by flash chromatography (Biotage SP1 instrument, SNAP cartridge silica 50g, Hex/EtOAc 9:1,10CV) to give the title compound (0.35 g; yield: 83%)

¹H NMR(300MHz,CDCl₃)7.37–7.08(m,5H),4.44(t,2H),4.38–4.27(m,1H),4.06(t,2H),2.68–2.52(m,1H),2.52–2.35(m,1H),2.35–2.26(m,2H),2.07(s,3H),1.97(m,6H),1.80–1.66(m,2H),1.66–1.52(m,2H),1.50–1.29(m,4H)。

Example 4

Synthesis of 4- (nitrooxy) butyl 3-methyl-3- (3-methyl-1, 4-dioxo-1, 4-dihydronaphthalen-2-yl) butanoic acid ester (Compound 4)

Step 1 Synthesis of 6-hydroxy-4, 4, 5-trimethyl-3, 4-dihydro-2H-benzo [ H ] chromen-2-one

Methanesulfonic acid (30mL) was heated at 70 ℃. 2-methylnaphthalene-1, 4-diol (4.75g,25.0mmol) and methyl 3-methylbut-2-enoate (2.85g,25.0mmol,1eq) were added rapidly at the same time and the reaction was heated at this temperature for 2 hours. The reaction was then poured into water and after cooling extracted with EtOAc (3 × 100 mL). The combined organic layers were washed with water, saturated NaHCO in sequence₃Washed with water and brine, dried (Na)₂SO₄) Filtered and evaporated. The residue was purified by flash chromatography (Biotage system, 2SNAP cartridge silica 100g, eluent: n-hexane/ethyl acetate 90/10 to n-hexane/ethyl acetate 70/30 in 10 column volumes) to give the title compound (2.26g, yield: 35%) as a pale yellow solid.

¹H NMR(300MHz,CDCl₃)7.90(d,J＝8.3,2H),7.45(d,J＝8.0,2H),3.88–3.67(m,2H),2.45(s,3H),1.56(s,6H)。

Step 2 Synthesis of 3-methyl-3- (3-methyl-1, 4-dioxo-1, 4-dihydronaphthalen-2-yl) butanoic acid

To the stirred 6-hydroxy-4, 4, 5-trimethyl-3, 4-dihydro-2H-benzo [ H ]]To a solution of benzopyran-2-one (1.2g,4.44mmol) in 10% acetonitrile in water (100mL) was added a solution of freshly recrystallized NBS (0.8g,4.44mmol,1eq) in acetonitrile (20 mL). The reaction was stirred for 1 hour then diluted with water (100mL) and Et₂O (3 × 100 mL). The combined organic layers were washed with water and brine and dried (Na)₂SO₄) Filtered and evaporated. The residue was purified by flash chromatography (Biotage System, SNAP Cartridge silica 100g, eluent: n-hexane/ethyl acetate 70/30 to n-hexane/ethyl acetate 50/50 in 8 column volumes) to give the title compound as a yellow oil (0.86g, yield: 68%).

¹H NMR(300MHz,CDCl₃)12.11(m,1H),8.06-7.99(m,1H),7.87–7.78(m,1H),7.70–7.58(m,2H),3.02(s,2H),2.14(s,3H),1.44(s,6H)。

Step 3- (Nitroxy) butyl 3-methyl-3- (3-methyl-1, 4-dioxo-1, 4-dihydronaphthalen-2-yl) butanoate (Compound 4)

To 4-hydroxybutyl nitrate (synthesized in example 1, steps 1,2 and 3) (150mg,1.11mmol) and 3-methyl-3- (3-methyl-1, 4-dioxo-1, 4-dihydronaphthalen-2-yl) butyric acid (303mg,1.11mmol,1eq) cooled to 0 ℃ in dry CH₂Cl₂EDC (234mg,1.22mmol,1.1eq) and a catalytic amount of DMAP were added to the solution in (1). The reaction was stirred at 0 ℃ for 6 hours, then washed with water, HCl 0.1M, water and brine, dried (Na)₂SO₄) Filtered and evaporated. The residue was purified by flash chromatography (Biotage System, SNAP Cartridge silica 100g, eluent: n-hexane/ethyl acetate 80/20 to n-hexane/ethyl acetate 70/30 in 8 column volumes) to give the title compound (268mg, yield: 62%) as a yellow oil.

¹H NMR(300MHz,CDCl₃)8.02(dd,J＝6.1,2.9,1H),7.89–7.80(m,1H),7.70–7.58(m,2H),4.36(t,J＝6.3,2H),3.94(t,J＝6.2,2H),3.10(s,2H),2.32(s,3H),1.67(dt,J＝10.8,6.1,2H),1.65-1.45(m,14H)。

Example 5

Synthesis of 6- (nitrooxy) hexyl 4- (4-fluorophenyl) -4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 5)

Step 1 Synthesis of 4- (2, 5-dihydroxy-3, 4, 6-trimethylphenyl) -4- (4-fluorophenyl) butanoic acid

The reaction was carried out according to the conditions described in Mitsuru et al, J.Med.chem.Soc.,1989,32, 2214-one 2221.

Boron trifluoride etherate (0.21 ml; 1.65mmol) was added dropwise at 60 ℃ over the course of 10 minutes to a mixture of trimethylhydroquinone (0.50 g; 3.30mmol) and gamma- (4-fluorophenyl) -gamma-butyrolactone (0.59 g; 3.30mmol) in toluene (10 ml). The mixture was stirred for 2 hours and then the solvent was distilled off under reduced pressure. The residue was purified by flash chromatography (Biotage System, SNAP cartridge silica 50g, from 9% to 60% EtOAc in n-hexane over 10 column volumes) to give the title compound as an orange solid (0.48 g; yield: 43%).

Step 2 Synthesis of 4- (4-fluorophenyl) -4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dien-1-yl) butanoic acid

To 4- (2, 5-dihydroxy-3, 4, 6-trimethylphenyl) -4- (4-fluorophenyl) butanoic acid (0.48 g; 1.44mmol) in CH₃CN:H₂Ammonium cerium nitrate (2.04 g; 3.60mmol) was added to a solution of O1: 1(40 ml). The mixture was stirred at room temperature for 3 hours, then poured into H₂O (30 ml). Et was added₂O (20ml), the two phases were separated and the organic layer was washed with Et₂O (2X20ml) extraction. The combined organic layers were washed with brine, washed with Na₂SO₄Drying and concentration gave 430mg of the title compound without further purification.

¹H NMR(300MHz,CDCl₃)7.32–7.19(m,3H),6.97(m,2H),4.29(t,J＝7.6,1H),2.70–2.25(m,4H),2.10(s,3H),2.03–1.89(m,6H)。

Step 3-6- (nitrooxy) hexyl 4- (4-fluorophenyl) -4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butyrate (Compound 5)

To 4- (4-fluorophenyl) -4- (2,4, 5-trimethyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) butanoic acid (0).22g of the total weight of the mixture; 0.66mmol) and 6-nitrooxy-hex-1-ol (synthesized in example 2, step 1) (0.12 mg; 0.66mmol) of CH₂Cl₂To a solution (5ml) was added 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC) (0.19 g; 0.98mmol) and a catalytic amount of DMAP. The solution was stirred at 0 ℃ for 30 minutes and at room temperature for 4 hours, then with NaH₂PO₄5% solution (5ml), H₂O (5ml) and brine. The organic layer was washed with Na₂SO₄Dried and concentrated under reduced pressure. The residue was purified by flash chromatography (Biotage SP1 instrument, SNAP cartridge silica 50g, Hex/EtOAc 9:1,10 column volumes) to give the title compound (0.18 g; yield: 58%).

¹H NMR(300MHz,CDCl₃)7.36–7.17(m,3H),7.05–6.88(m,2H),4.44(t,2H),4.28(t,1H),4.06(t,2H),2.67–2.33(m,2H),2.33–2.22(m,2H),2.11(s,3H),2.00(s,3H),1.95(s,3H),1.80–1.55(m,4H),1.49–1.30(m,4H)。

Example 6

Synthesis of 4- (nitrooxy) butyl 4-phenyl-4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 6)

Step 1: Synthesis of 4-chlorobutyl 4-nitrobenzoate

To the cooled to 0 deg.C solution of 4-chlorobutanol (1.09 g; 10.04mmol) and TEA (1.7 mL; 12.05mmol) in CH₂Cl₂To the solution (25ml) was added 4-nitrobenzoyl chloride (2.23 g; 12.05mmol) portionwise. The mixture was stirred at room temperature for 2 hours, then with NaH₂PO₄(25ml)、H₂O and brine wash. Will be provided withThe residue was purified by flash chromatography (Biotage SP1 instrument, SNAP cartridge silica 100g, n-hexane/EtOAc 9:1,10 column volumes) to give the title compound (2.48 g; yield: 96%).

¹H NMR(300MHz,CDCl₃)8.38–8.25(m,2H),8.25–8.14(m,2H),4.55–4.33(m,2H),3.73–3.53(m,2H),2.13–1.85(m,4H)。

Step 2 Synthesis of 4- (nitrooxy) butyl 4-nitrobenzoate

To 4-chlorobutyl 4-nitrobenzoate (2.48 g; 9.62mmol) in CH₃To a solution of CN (40ml) was added NaI (5.77g,38.30 mmol). The mixture was heated in a microwave apparatus (40 min; 120 ℃ C.), then the salts were filtered off and the solvent was distilled off under reduced pressure. EtOAc (50mL) was added and the solution was taken over Na₂S₂O₅5% solution (50ml), H₂O and brine wash. The organic layer was washed with Na₂SO₄Dried and concentrated under reduced pressure. The residue was dissolved in CH₃CN (40ml) and AgNO added₃(1.97 g; 11.54 mmol). The mixture was heated at 120 ℃ for 15 minutes with microwaves, then the salts were filtered off and the solvent was distilled off under reduced pressure. EtOAc (30mL) was added, the precipitate was again removed by filtration and the solvent was evaporated off. This procedure was repeated 3 times, and then the organic layer was washed with brine, Na₂SO₄Dried and concentrated under reduced pressure. The residue was purified by flash chromatography (Biotage SP1 instrument, SNAP cartridge silica 100g, 5% to 40% EtOAc in n-hexane solution over 10 column volumes) to give the title compound as a clear oil (2.50 g; yield: 93%).

Step 3-Synthesis of 4-hydroxybutyl nitrate

To 4- (nitre) cooled to 0 DEG CAryloxy) butyl 4-nitrobenzoate (2.5 g; 8.76mmol) in THF (30ml) was added dropwise NaOH 2M (8.7 ml; 17.53 mmol). The solution was stirred at room temperature for 4 hours and then with NaHCO₃Saturated solution (20ml) diluted and CH₂Cl₂(3 × 30 ml). The combined organic layers were washed with Na₂SO₄Dried and concentrated under reduced pressure. The residue was purified by flash chromatography (Biotage SP1 instrument, SNAP cartridge silica 50g, 10% to 100% EtOAc in n-hexane solution in 10 column volumes) to give the title compound (1.0 g; yield: 85%).

¹H NMR(300MHz,CDCl₃)4.50(td,J＝6.5,2H),3.70(t,J＝6.2,2H),1.95–1.76(m,2H),1.76–1.59(m,2H)。

Step 4 Synthesis of 4- (nitrooxy) butyl 4-phenyl-4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 6)

To 4-phenyl-4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dien-1-yl) butanoic acid (synthesized in example 3, steps 1 and 2) (0.27 g; 0.86mmol) and 4-hydroxybutyl nitrate (0.15 mg; 0.86mmol) in CH₂Cl₂To a solution (4ml) was added 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC) (0.25 g; 1.30mmol) and a catalytic amount of DMAP. The solution was stirred at 0 ℃ for 30 minutes and at room temperature for 4 hours, then with NaH₂PO₄5% solution (5ml), H₂O (5ml) and brine. The organic layer was washed with Na₂SO₄Dried and concentrated under reduced pressure. The residue was purified by flash chromatography (Biotage SP1 instrument, SNAP cartridge silica 50g, Hex/EtOAc 9:1,10 column volumes) to give the title compound as an orange oil (0.23 g; yield: 62%).

¹H NMR(300MHz,CDCl₃)7.38–7.11(m,5H),4.47(m,2H),4.34(t,J＝7.7,1H),4.09(t,J＝6.0,2H),2.73–2.52(m,1H),2.52–2.23(m,3H),2.07(s,3H),1.97(m,6H),1.89–1.65(m,4H)。

Example 7

Synthesis of 4- (nitrooxy) butyl 4- (4-fluorophenyl) -4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 7)

To 4- (4-fluorophenyl) -4- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dien-1-yl) butanoic acid (synthesized in example 5, steps 1 and 2) (0.19 g; 0.57mmol) and 4-hydroxybutyl nitrate (synthesized in example 6, steps 1,2 and 3) (0.10 mg; 0.57mmol) in CH₂Cl₂To a solution (4ml) was added 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC) (0.16 g; 0.86mmol) and a catalytic amount of DMAP. The solution was stirred at 0 ℃ for 30 minutes and at room temperature for 4 hours, then with NaH₂PO₄5% solution (5ml), H₂O (5ml) and brine. The organic layer was washed with Na₂SO₄Dried and concentrated under reduced pressure. The residue was purified by flash chromatography (Biotage SP1 instrument, SNAP cartridge silica 50g, n-hexane/EtOAc 9:1,10 column volumes) to give the title compound as an orange oil (0.15 g; yield: 59%).

¹H NMR(300MHz,CDCl₃)7.35–7.15(m,2H),7.06–6.87(m,2H),4.47(m,2H),4.28(t,J＝7.7,1H),4.09(t,J＝6.0,2H),2.68–2.22(m,4H),2.08(s,3H),1.97(m,6H),1.86–1.65(m,4H)。

Example 8

Synthesis of (5S,6R) -5, 6-bis (nitrooxy) heptyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate, the (5S,6R) -isomer of Compound 8

Step 1 Synthesis of hex-5-enyl 4-nitrobenzoate

To a solution of 5-hexen-1-ol (19.4 mL; 161.54mmol) in dichloromethane (513mL) at 0 deg.C was added p-nitrobenzoyl chloride (35.97g,193.85mmol) followed by dropwise addition of triethylamine (27.0mL,193.85mmol) in dichloromethane (150 mL). The mixture was stirred at room temperature for 21 hours, then washed with water, 1M aqueous HCl, brine. The organic layer was dried (Na)₂SO₄) And the solvent was removed under reduced pressure. The residue was purified by flash chromatography (Biotage System, two SNAP cartridges packed with silica 340g, eluent: n-hexane/ethyl acetate 90/10 to n-hexane/ethyl acetate 50/50 in 12 column volumes) to yield the title compound as a yellow oil (40.00g, 99%).

¹H NMR(300MHz,CDCl₃)8.30(dt,J＝9.0,3.0Hz,2H),8.22(dt,J＝9.0,3.0Hz,2H),5.83(1H,ddt,J＝16.9,10.2,6.7Hz),4.95-5.11(2H,m),4.39(2H,t,J＝6.6Hz),2.15(2H,m),1.84(2H,m)1.50-1.66(2H,m)。

Step 2 Synthesis of (5S) -5, 6-dihydroxyhexyl 4-nitrobenzoate

To a vigorously stirred solution of commercially available "AD mix α" (112.5g) in 1:1 water/t-butanol (822mL) at 0 deg.C was added hex-5-enyl 4-nitrobenzoate (20.00g,80.23 mmol). the mixture was vigorously stirred at 4 deg.C (chill-room) for 21 hours, the mixture was cooled to 0 deg.C and ethyl acetate (450mL) was added, then sodium metabisulfite (33.1g) was added in portions, the mixture was stirred at 0 deg.C for 30 minutes, then stirred at room temperature for 1 hour, the organic phase separated, the aqueous phase extracted with ethyl acetate, the combined organic extracts washed with brine, dried (Na)₂SO₄) And the solvent was removed under reduced pressure. By filtration through a short pad of silica gelPurification, eluting with ethyl acetate, yielded the title compound as an off-white solid (21.90g, 96%).

¹H NMR(300MHz,CDCl₃)8.30(dt,J＝9.0,2.0Hz,2H),8.21(dt,J＝9.0,2.0Hz,2H),4.39(t,J＝6.6Hz,2H),3.80-3.62(2H,m),3.47(1H,m),2.59(bs,1H),2.42(bs,1H),1.90-1.75(2H,m),1.73-1.45(4H,m)。

Step 3 Synthesis of (5S) -6-triphenylmethoxy-5-hydroxyhexyl 4-nitrobenzoate

To a solution of (5S) -5, 6-dihydroxyhexyl 4-nitrobenzoate (13.46g,47.53mmol) in dry N, N-dimethylformamide (123mL) under a nitrogen atmosphere was added triphenylmethyl chloride (14.57g,52.28mmol), followed by triethylamine (7.29mL,52.28mmol) and 4-dimethylaminopyridine (581mg,4.75 mmol). The resulting solution was stirred at room temperature for 23 hours. The mixture was poured into water and extracted with ether (3 times). The combined organic extracts were washed with saturated NH₄Aqueous Cl solution and water, then dried (Na)₂SO₄) And the solvent was removed under reduced pressure. Purification by flash chromatography eluting with 20% ethyl acetate/hexanes to 50% ethyl acetate/hexanes gave the title compound as a pale yellow oil (20.90g, 84%).

¹H NMR(300MHz,CDCl₃)8.28(d,J＝8.8Hz,2H),8.20(d,J＝8.8Hz,2H),7.49-7.42(m,6H),7.36-7.23(m,9H),4.36(t,J＝6.5Hz,2H),3.82(dp,J＝10.9,3.1Hz,1H),3.21(dd,J＝9.3,3.3Hz,1H),3.07(dd,J＝9.2,7.7Hz,1H),2.36(d,J＝2.9Hz,1H),1.86–1.72(m,2H),1.56–1.38(m,4H)。

Step 4 (5S) -6-triphenylmethoxy-5-tert-butyl diphenylsilanyloxyhexyl 4-nitrobenzoate synthesis

To a solution of (5S) -6-triphenylmethoxy-5-hydroxyhexyl 4-nitrobenzoate (7.10g,13.51mmol) in anhydrous N, N-dimethylformamide (65mL) under nitrogen was added imidazole (1.84g,27.02mmol) and the solution was cooled to 0 ℃. Tert-butyldiphenylchlorosilane (7.03mL,27.02mmol) was added and the solution was stirred at 0 ℃ for 10 minutes and then at room temperature for 15 hours. The mixture was poured into water and extracted with ether. The combined organic phases were dried (Na)₂SO₄) And the solvent was removed under reduced pressure. Purification by flash chromatography eluting with 5% ethyl acetate/hexanes afforded the title compound as an off-white foam (5.29g, 51%).

¹H NMR(300MHz,CDCl₃)8.28–8.20(m,2H),8.19–8.09(m,2H),7.67–7.53(m,4H),7.48–7.11(m,21H),4.22(t,J＝6.4Hz,2H),3.97–3.87(m,1H),3.15(dd,J＝9.3,4.8Hz,1H),3.03(dd,J＝9.2,6.4Hz,1H),1.78–1.44(m,4H),1.27(m,2H),1.02(s,9H)。

Step 5 Synthesis of (5S) -5-tert-butyl diphenylsilanyloxy-6-hydroxyhexyl 4-nitrobenzoate

To a solution of (5S) -6-triphenylmethoxy-5-tert-butyldiphenylsilanyloxyhexyl-4-nitrobenzoate (4.06g,5.32mmol) in dichloromethane (15mL) was added methanol (157mL) and p-toluenesulfonic acid monohydrate (202mg,1.06 mmol). The solution was stirred at room temperature for 17 hours. The solvent was evaporated under reduced pressure and the residue was dissolved in ethyl acetate and washed with saturated NaHCO₃Aqueous solution, water and brine. The organic layer was dried (Na)₂SO₄) And the solvent was distilled off under reduced pressure. Purification by flash chromatography (Biotage System, SNAP Cartridge silica 340g, eluent: n-hexane/ethyl acetate 90/10 to n-hexane/ethyl acetate 70/30 in 12 column volumes) afforded the title compound (1.33g, 48%) as a pale yellow oil.

¹H NMR(300MHz,CDCl₃)8.32–8.26(m,2H),8.20–8.15(m,2H),7.73–7.66(m,5H),7.48–7.35(m,5H),4.25(t,J＝6.5Hz,2H),3.83(dt,J＝10.3,5.3Hz,1H),3.52(ddd,J＝11.4,5.9,3.7Hz,1H),3.58(ddd,J＝11.4,4.8,3.1Hz,1H),1.79(bs,1H),1.70–1.46(m,4H),1.36(dd,J＝15.0,7.4Hz,2H),1.09(s,9H)。

Step 6 Synthesis of (5S) -5-tert-butyl diphenylsilanyloxy-6-oxohexyl 4-nitrobenzoate

To a solution of 0.4M (5S) -5-tert-butyldiphenylsilanyloxy-6-hydroxyhexyl 4-nitrobenzoate (9.29g,17.81mmol) in dichloromethane (44.5mL) was added silica-supported TEMPO (307 mg; 0.178mmol) followed by 0.5M aqueous KBr solution (3.53 mL). The mixture was cooled to 0 ℃ and stirred vigorously. A solution of 0.37M NaOCl (10-15% active Cl) (13.73mL) in water (46.30mL) was added and the mixture was treated with solid NaHCO₃And (6) buffering. The mixture was stirred vigorously at 0 ℃ for 3.5 hours. The solid was filtered off and washed thoroughly with dichloromethane and water. The organic layer was separated and the aqueous layer was extracted with dichloromethane. The combined organic phases were dried (Na)₂SO₄) And the solvent was evaporated under reduced pressure to give the crude title compound (9.09g, 98%) as a pale yellow oil, which was used without further purification.

¹H NMR(300MHz,CDCl₃)9.64(d,J＝1.4Hz,1H),8.30(dt,J＝9.0,2.0Hz,2H),8.19(dt,J＝9.0,2.0Hz,2H),7.75-7.60(m,4H),7.55-7.35(m,6H),4.30(t,J＝6.4Hz,2H),4.09(td,J＝5.6,1.4Hz,1H),1.90-1.35(m,6H),1.12(9H,s)。

Step 7 Synthesis of (5S,6R) -6-hydroxy-5-tert-butyldiphenylsilanyloxy heptyl 4-nitrobenzoate and (5S,6S) -6-hydroxy-5-tert-butyldiphenylsilanyloxy heptyl 4-nitrobenzoate

To a 250mL Schlenk bottle (dry and N used)₂Purified) was added (1R,2S) - (+) - (dibutylamino) -1-phenyl-1-propanol (3.28g,12.45mmol,1eq) followed by 2M dimethyl zinc in toluene (37.35mL,74.7mmol,6 eq). The resulting yellow solution was cooled to 0 ℃ and a solution of (5S) -5-tert-butyldiphenylsilanyloxy-6-oxohexyl 4-nitrobenzoate (6.47g,12.45mmol) in dry toluene (40mL) was slowly added. The solution was stirred at 0 ℃ for 10 minutes, then warmed to room temperature and stirred for 18 hours. The solution was cooled to 0 ℃ and saturated NH was added₄The reaction was quenched slowly with aqueous Cl (75 mL). The mixture was warmed to room temperature and extracted with ethyl acetate. The combined organic phases were dried (Na)₂SO₄) And the solvent was distilled off under reduced pressure. Purification by flash chromatography eluting with 15% ethyl acetate/n-hexane to 25% ethyl acetate/n-hexane afforded the title compound (4.31g, 65%) as a yellow oil which was an inseparable mixture of diastereomers 5S,6R (major) and 5S,6S (minor).

(5S,6R) -major diastereomer

¹H NMR(300MHz,CDCl₃)8.29(dt,J＝9.0,2.0Hz,2H).8.16(dt,J＝9.0,2.0Hz,2H),7.75-7.65(4H,m),7.50-7.30(6H,m),4.20(t,J＝6.4Hz,2H),3.83(m,1H),3.72(m,1H),2.09(d,J＝4.9Hz,1H),1.65-1.20(m,6H),1.12(d,J＝6.5Hz,3H),1.09(s,9H)。

(5S,6S) -minor diastereomer:

¹H NMR(300MHz,CDCl₃)8.29(dt,J＝9.0,2.0Hz,2H),8.16(dt,J＝9.0,2.0Hz,2H),7.75-7.65(m,4H),7.30-7.50(m,6H),4.20(t,J＝6.4Hz,2H),3.71(1H,m),3.60(1H,m),2.21(d,J＝6.1Hz,1H),1.65-1.20(m,6H),1.16(d,J＝6.3Hz,3H),1.09(s,9H)。

step 8 Synthesis of (5S,6R) -5, 6-dihydroxyheptyl 4-nitrobenzoate

To a solution of (5S,6R) -6-hydroxy-5-tert-butyldiphenylsilanyloxyheptyl 4-nitrobenzoate (805mg,1.50mmol) in diethyl ether (50mL) was added dropwise a solution of 3% HCl in methanol (prepared by adding acetyl chloride (2.00mL) to methanol (50 mL). The solution was stirred at room temperature for 41 hours. Amberlite IRA 400(OH) resin was added and the mixture was stirred for 1 hour, and the resin was added again until pH 7/8. The resin was filtered off, washed with ethyl acetate and then with methanol. The solvent was evaporated under reduced pressure and the residue was taken up in ethyl acetate and saturated NaHCO₃The aqueous solution was partitioned and the aqueous phase was extracted with ethyl acetate. The combined organic phases were dried (Na)₂SO₄) And the solvent was distilled off under reduced pressure. Purification by flash chromatography eluting with 10% ethyl acetate/hexanes to 90% ethyl acetate/hexanes gave the title compound (189mg, 42%) as a mixture of diastereomers 5S,6R (major) and 5S,6S (minor) as a pale yellow oil. Diastereomeric excess (5S,6R) ═ 56.4%.

The diastereomer was purified by preparative HPLC (conditions: column Phenomenex Gemini phenyl-hexyl 100X21.2mm/5m

The mobile phase A is water and 0.1 percent formic acid; b, methanol and 0.1 percent formic acid.

The flow rate was 25 mL/min.

Gradient change with time 0min 45% A/55% B; 5.5min, 40% A/60% B; 5.6min, 0% A/100% B; 7.6min 0% A/100% B; 7.7min 45% A/55% B. Detector 254nm) gave Compound H (135mg) as a white solid. Enantiomeric excess/diastereomeric excess-72.1%.

¹H NMR(300MHz,CDCl₃)8.32(dt,J＝9.0,2.0Hz,2H),8.23(dt,J＝9.0,2.0Hz,2H),4.42,(t,J＝6.5Hz,2H),3.84(m,1H),3.66(m,1H),1.42-2.0(m,8H),1.19(d,J＝6.4Hz,3H)。

Other deprotection methods

At 0 ℃ to (5S) with stirringTo a solution of 6R) -6-hydroxy-5-tert-butyldiphenylsilanyloxyheptyl 4-nitrobenzoate (2.96g,5.52mmol) in acetonitrile (60mL) was added boron trifluoride-diethyl etherate (3.5mL,5eq) and the reaction was stirred at room temperature for 6 h. The reaction was cooled to 0 ℃ and then quenched with saturated sodium bicarbonate solution. The reaction mixture was diluted with ethyl acetate (50mL), the organic layer was separated, washed successively with water and brine (5mL each), and dried (Na)₂SO₄) The solvent was filtered and evaporated under reduced pressure. The residue was purified by flash chromatography (Biotage system, 2 × SNAP cartridge silica 100g, eluent: gradient elution from n-hexane/ethyl acetate 35/65 to n-hexane/ethyl acetate 30/70 over 7 column volumes) to give the title compound (1.47g, 90%) as a mixture of diastereomers 5S,6R (major) and 5S,6S (minor) as a colorless oil.

The diastereomers were separated by preparative HPLC (conditions: column Phenomenex Gemini phenyl-hexyl 100X21.2mm/5 m) to give the major diastereomer as a white solid (1.09g, 66%).

Step 9 Synthesis of (5S,6R) -5, 6-di (nitrooxy) heptyl 4-nitrobenzoate

To a stirred mixture of (5S,6R) -5, 6-dihydroxyheptyl 4-nitrobenzoate (400mg,1.34mmol), tetrabutylammonium nitrate (863mg,2.82mmol,2.1eq) and 2, 6-di-tert-butyl-4-methylpyridine (580mg,2.82mmol,2.1eq) cooled to-78 deg.C was added dry CH₂Cl₂Trifluoromethanesulfonic anhydride (0.778g,2.75mmol,2.05eq) was added dropwise to the solution in (1) and the reaction was stirred at-78 ℃ for 1 hour and then returned to room temperature. The reaction was then quenched with water and the organic layer was separated, washed with water and brine, dried over sodium sulfate, filtered and evaporated. The residue was purified by flash chromatography (Biotage SP4, SNAP100 column, 20% to 30% EtOAc in n-hexane over 10 column volumes) to give the title compound as a yellow oil (406mg, yield: 77%).

¹H NMR(300MHz,CDCl₃)8.32(dt,J＝9.02.0Hz,2H),8.22(dt,J＝9.0,2.0Hz,2H),5.30(m,1H),4.42(td,J＝6.4Hz,1H),1.95-1.55(m,6H),1.43(d,J＝6.7Hz,3H)。

Step 10 Synthesis of (1R,2S) -6-hydroxy-1-methyl-2- (nitrooxy) hexyl nitrate

To a solution of (5S,6R) -5, 6-bis (nitrooxy) heptyl 4-nitrobenzoate (163mg,0.42mmol) in tetrahydrofuran (1.27mL) and ethanol (1.27mL) was added 1M aqueous NaOH solution (546. mu.L, 0.546 mmol). The resulting yellow solution was stirred at room temperature for 1.5 hours. The solvent was concentrated under reduced pressure and the aqueous residue was taken up in ethyl acetate and saturated NaHCO₃The aqueous solution was partitioned. The organic layer was washed with saturated NaHCO₃The aqueous layer was washed and the aqueous layer was back extracted with ethyl acetate. The combined organic phases were dried (Na)₂SO₄) And the solvent was concentrated to a small volume (2 mL). The product was carefully purified by flash chromatography (Biotage system, SNAP cartridge silica 100g, eluent: gradient elution from n-hexane/ethyl acetate 75/25 to n-hexane/ethyl acetate 50/50 over 8 column volumes) to separate the two diastereomers to give the title compound as a colorless oil (0.147g, 90%).

The following conditions can be used to obtain optimal separation using the thumb investifier SFC system:

column CHIRALPACK IB 250X10mm (5 μm)

Cosolvent n-hexane/2-propanol 1/1

Isocratic elution of CO₂Cosolvent 90/10

The flow rate is 10ml/min T column at 40 ℃; injection volume 80. mu.l; wavelength of detector 210nm

The running time is 8.5 min; the period is 3 min; the injection amount is 14-16mg

(sample preparation: 800mg of crude Compound in 4ml MeOH)

¹H NMR(300MHz,CDCl₃)5.25-5.34(m,2H),3.70(t,J＝5.9Hz,2H),1.47-1.85(m,7H),1.42(d,J＝6.8Hz,3H)。

Step 11 Synthesis of (5S,6R) -5, 6-bis (nitrooxy) heptyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 8)

To 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dien-1-yl) butanoic acid (prepared in example 1, step 2) (146mg,0.583mmol,1eq) and (1R,2S) -6-hydroxy-1-methyl-2- (nitrooxy) hexyl nitrate (140mg,0.583mmol) cooled to 0 deg.C in dry CH₂Cl₂EDC (117mg,0.612mmol,1.05eq) and a catalytic amount of DMAP were added to the solution in (1). The reaction was stirred at this temperature for 5 hours and then washed with water, HCl 0.1M, water and brine. The organic solution was dried (Na)₂SO₄) Filtered and evaporated. The residue was purified by flash chromatography (Biotage SP4 system, SNAP cartridge silica 100g, eluent: gradient elution from n-hexane/ethyl acetate 80/20 to n-hexane/ethyl acetate 70/30 over 8 column volumes) to give the title compound as a yellow oil (210mg, 76%).

¹H NMR(300MHz,CDCl₃)5.32–5.17(m,2H),3.99(t,J＝6.2,2H),2.98(s,2H),2.14(s,3H),1.98–1.94(m,6H),1.76–1.45(m,15H),1.43(s,6H),1.39(d,J＝6.7,3H)。

Example 9

Synthesis of (4- (nitrooxy) butyl 4- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -4-phenylbutyrate (Compound 9)

Step 1 Synthesis of 4- (2, 5-dihydroxy-3, 4-dimethoxy-6-methylphenyl) -4-phenylbutyric acid

The reaction was carried out according to the conditions described in Mitsuru et al, J.Med.chem.Soc.,1989,32, 2214-one 2221.

Boron trifluoride etherate (0.23 ml; 1.59mmol) was added dropwise at 60 ℃ over 10 minutes to a mixture of 2, 3-dimethoxy-5-methylbenzene-1, 4-diol (1.00 g; 5.49mmol) and gamma-phenyl-gamma-butyrolactone (0.89 g; 5.49mmol) in toluene (55 ml). The mixture was stirred for a further 3 hours and then the solvent was distilled off under reduced pressure. The residue was purified by flash chromatography (Biotage System, SNAP cartridge silica 100g, from 9% to 60% EtOAc in n-hexane over 10 column volumes) to give the title compound as a pale yellow solid (0.80 g; yield: 42%).

¹H NMR(300MHz,CDCl₃)7.44–7.10(m,5H),5.42(m,2H),4.49(m,1H),3.99–3.81(m,6H),2.77–2.47(m,2H),2.47–2.29(m,2H),2.10(s,3H)。

Step 2 Synthesis of 4- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dien-1-yl) -4-phenylbutyric acid

To 4- (2, 5-dihydroxy-3, 4-dimethoxy-6-methylphenyl) -4-phenylbutyric acid (0.40 g; 1.15mmol) in CH₃CN:H₂To a solution of O1: 1(40ml) was added cerium ammonium nitrate (1.63 g; 2.89 mmol). The mixture was stirred at room temperature for 3 hours, then poured into H₂O (30 ml). Et was added₂O (20ml), the two phases were separated and the organic layer was washed with Et₂O (2X20ml) extraction. The combined organic layers were washed with brine, washed with Na₂SO₄Drying and concentration gave 400mg of the title compound without further purification.

Step 3 Synthesis of (4- (nitrooxy) butyl 4- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -4-phenylbutyrate (Compound 9)

To 4- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) -4-phenylbutanoic acid (0.40 g; 0.57mmol) and 4-hydroxybutyl nitrate (synthesized in example 6, steps 1,2 and 3) (0.10 mg; 0.57mmol) in CH₂Cl₂To a solution (4ml) was added 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC) (0.16 g; 0.86mmol) and a catalytic amount of DMAP. The solution was stirred at 0 ℃ for 30 minutes and at room temperature for 4 hours, then with NaH₂PO₄5% solution (5ml), H₂O (5ml) and brine. The organic layer was washed with Na₂SO₄Dried and concentrated under reduced pressure. The residue was purified by flash chromatography (Biotage SP1 instrument, SNAP cartridge silica 25g, Hex/EtOAc 8:2,10 column volumes) to give the title compound as a red oil (95 mg; yield: 36%).

¹H NMR(300MHz,CDCl₃)7.38–7.15(m,5H),4.49(m,2H),4.35(t,J＝7.7,1H),4.11(t,J＝6.0,2H),3.98(s,6H),2.74–2.52(m,1H),2.52–2.25(m,3H),2.09(s,3H),1.89–1.66(m,4H)。

Example 10 in vitro antioxidant Activity (TBARS assay)

After NADPH-induced lipid peroxidation of membrane lipids in rat liver microsomes, compound (1) (example 1), its precursor (3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) butanoic acid, described in step 2 of example 1 (intermediate 2)) and the reference antioxidant compound were evaluated by visual spectroscopic detection of 2-thiobarbituric acid reactive species (TBARS).

Microsomal membranes were prepared from male Wistar rats (200-250g) by differential centrifugation (8000g,20 min; 120000g, 1h) in HEPES/sucrose buffer (10mM,250mM, pH 7.4) and stored at-80 ℃. Incubation in Tris-HCl/KCl (100mM/150mM, pH 7.4) containing a microsomal membrane (2mg protein/mL), sodium ascorbate (100. mu.M) and a DMSO solution of the test compound was performed at 37 ℃.

By adding ADP-FeCl₃And NADPH (method A) or 2.5. mu.M FeSO₄(method B) initiation of lipid peroxidation (according to the method described by Boschi D. et al, J.Med.chem.2006,49: 2886-2897). Samples were taken from the incubation mixtures at 5, 15 and 30 minutes and treated with trichloroacetic acid (TCA) 10% w/v.

Lipid peroxidation was assessed by spectrophotometric (543nm) determination of TBARS, which is composed mainly of Malondialdehyde (MDA). TBARS concentrations (expressed in nmol/mg protein) were obtained by interpolation using MDA standard curves. The antioxidant activity of the test compounds was evaluated as a percentage inhibition of TBARS production relative to the control samples using the values obtained after 30 minutes incubation. IC (integrated circuit)₅₀Values were calculated by nonlinear regression analysis.

The results are reported in table 1, indicating that compound (1) inhibits TBARS production in a concentration-dependent manner, its efficacy (IC)₅₀28 μ M) are comparable to well known antioxidant compounds such as ferulic or caffeic acid, edaravone or melatonin.

Results IC inhibition of TBARS production after incubation for 30 min at 37 ℃₅₀And (4) showing.

Method A inhibition by ADP-FeCl₃And NADPH-induced lipid peroxidation of rat liver.

Method B inhibition by FeSO₄And ascorbic acid-induced lipid peroxidation of rat liver.

^aTested at a concentration of 1 mM;

^bchegaev, K, et al, J.Med.chem.2009,52: 574-

^cChegaev, K.et al, J.Pineal Res.2007,42: 371-

Example 11 intraocular pressure lowering Activity in hypertonic saline-induced increases in intraocular pressure (IOP) in rabbits

The intraocular pressure (IOP) lowering activity of compound (1) (example 1) was evaluated in an animal model of elevated intraocular pressure.

Adult male New Zealand white rabbits with a body weight of 1.8-2.0Kg were used in the experiment.

Animals were anesthetized with 20mg/ml/kg sodium pentobarbital. An increase in intraocular pressure was induced by injecting 0.1ml of hypertonic saline solution (5%) on both sides of the vitreous (Krauss et al, 2011, Orihashi et al, 2005).

Intraocular pressure was measured with Tono-PenXL before injection of hypertonic saline (basal value) and after 30, 60, 90, 120, 240 and 360 minutes of injection. Immediately after injection of hypertonic saline, vehicle (5% Cremophor-EL; 0.3% DMSO,0.2mg/ml benzalkonium chloride (BAC) in PBS, pH 6.0) or the compound of the invention was instilled as eye drops. The eyes were randomly assigned to different treatment groups. The vehicle or compound of the invention is infused directly into the conjunctival sac at the desired dose. Immediately prior to each set of pressure measurements, one drop of 0.2% oxybuprocaine hydrochloride (Novesine, Sandoz) diluted 1:1 with saline was instilled in each eye.

Results the intraocular pressure lowering activity of compound (1) is shown in table 2 as the average value of intraocular pressure measurements at 60 minutes and 120 minutes after topical administration.

Example 12

Synthesis of (S) -5, 6-di (nitrooxy) hexyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 15; the (S) -isomer of Compound (10))

Step 1 Synthesis of (5S) -5, 6-di (nitrooxy) hexyl 4-nitrobenzoate

To a stirred solution of fuming nitric acid (7.7mL,91.8mmol,10eq) in dichloromethane (60mL) at-78 deg.C was added sulfuric acid (4mL) and after stirring for 5 minutes was added a solution of (5S) -5, 6-dihydroxyhexyl 4-nitrobenzoate (prepared in step 2 of example 8) (5.2g,9.2mmol) in dichloromethane (30mL), and the reaction was stirred at that temperature for 30 minutes. The crude mixture was then poured onto ice and the organic layer was extracted, washed with water, brine, dried over sodium sulfate and evaporated to give the title compound as a pale yellow oil (6.8g, 100%). The residue obtained was used in the next step without further purification.

¹H NMR(300MHz,CDCl₃)8.32(d,J＝8.9Hz,2H),8.26–8.15(m,2H),5.39–5.25(m,1H),4.78(dd,J＝12.9,3.1Hz,1H),4.52(dd,J＝12.9,6.4Hz,1H),4.46–4.35(m,2H),1.97–1.77(m,4H),1.77–1.49(m,2H)。

Step 2 (2S) -6-hydroxyhexane-1, 2-diyl dinitrate synthesis:

to a stirred solution of (5S) -5, 6-di (nitrooxy) hexyl 4-nitrobenzoate (prepared in step 1) (6.8g,18.2mmol) in 1/1 ethanol/THF (30mL each) mixture at 0 deg.C was added 2M sodium hydroxide solution (9.1mL,2eq) and the reaction was stirred for 2 hours. The reaction solution was diluted with ethyl acetate and water (100mL each) and extracted. The organic layer was washed successively with water and brine, dried over sodium sulfate and evaporated. The oily residue was purified by column chromatography (SNAP100, gradient system from 4/6 ethyl acetate/n-hexane to 60/40 ethyl acetate/n-hexane) to give the title compound as a colourless oil (3.82g, 93%).

¹H NMR(300MHz,CDCl₃)5.32(qd,J＝6.7,3.0Hz,1H),4.77(dd,J＝12.9,3.0Hz,1H),4.49(dd,J＝12.9,6.6Hz,1H),3.68(d,J＝5.5Hz,2H),1.89–1.71(m,2H),1.70–1.48(m,5H),1.46(s,1H)。

Step 3 Synthesis of (S) -5, 6-bis (nitrooxy) hexyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butyrate

To a stirred solution of 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) butanoic acid (201 mg; 0.80mmol), prepared as described in example 1, steps 1 and 2, and (2S) -6-hydroxyhexane-1, 2-diyl dinitrate (181 mg; 0.80mmol), prepared in step 2, in DCM (5ml) cooled to 0 deg.C was added EDAC (137 mg; 0.89mmol) and a catalytic amount of DMAP. The reaction was stirred at 0 ℃ overnight. The crude product was then washed with water, HCl 1N, water and brine, dried and evaporated in vacuo. The crude product was purified by flash chromatography [ Cy/EtOAc: 0% to 20% (1CV), 20% to 40% (7CV), 40% to 60% (2CV) ] to yield 246mg of the title compound as a yellow oil (yield: 67.1%).

¹H NMR (300MHz, acetone) 5.49(qd, J ═ 6.6,2.6Hz,1H),5.01(dd, J ═ 13.0,2.6Hz,1H),4.73(dd, J ═ 13.0,6.3Hz,1H),4.00(t, J ═ 6.3Hz,2H),2.95(s,2H),2.13(s,3H),1.94(s, J ═ 6.3Hz,6H), 1.90-1.79 (m,2H), 1.70-1.58 (m,2H),1.52(dt, J ═ 8.0,5.7Hz,2H),1.43(s,6H) — α_D ²⁰＝+2.2(0.44％MeOH)

Example 13

Synthesis of (R) -5, 6-bis (nitrooxy) hexyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 16; the (R) -isomer of Compound 10)

Step 1 Synthesis of (5R) -5, 6-dihydroxyhexyl 4-nitrobenzoate

To a vigorously stirred solution of commercially available "AD mix β" (112.5g) in 1:1 water/t-butanol (822mL) at 0 deg.C was added hex-5-enyl 4-nitrobenzoate (prepared in example 8, step 1) (20.00g,80.23 mmol.) the mixture was stirred vigorously at 4 deg.C (cold room) for 21 hours, the mixture was cooled to 0 deg.C and ethyl acetate (450mL) was added, then sodium metabisulfite (33.1g) was added slowly in portions, the mixture was stirred at 0 deg.C for 30 minutes, then stirred at room temperature for 1 hour, the organic phase was separated and the aqueous phase extracted with ethyl acetate, the combined organic extracts were washed with brine, dried (Na)₂SO₄) And the solvent was distilled off under reduced pressure. The filtrate was purified through a short pad of silica gel eluting with ethyl acetate to give the title compound as an off-white solid (20.5g, 90.2%).

¹H NMR(300MHz,CDCl₃)8.30(dt,J＝9.0,2.0Hz,2H),8.21(dt,J＝9.0,2.0Hz,2H),4.39(t,J＝6.6Hz,2H),3.80-3.62(2H,m),3.47(1H,m),2.59(bs,1H),2.42(bs,1H),1.90-1.75(2H,m),1.73-1.45(4H,m)。

Step 2 Synthesis of (5R) -5, 6-di (nitrooxy) hexyl 4-nitrobenzoate

To a stirred solution of fuming nitric acid (7.7mL,91.8mmol,10eq) in dichloromethane (60mL) at-78 ℃ was added sulfuric acid (4mL) and after stirring for 5 minutes was added a solution of (5R) -5, 6-dihydroxyhexyl 4-nitrobenzoate (prepared in step 1) (5.2g,9.2mmol) in dichloromethane (30mL), and the reaction was stirred at that temperature for 30 minutes. The crude mixture was then poured onto ice and the organic layer was extracted, washed with water, brine, dried over sodium sulfate and evaporated to give the title compound as a pale yellow oil (6.8g, 100%). The residue obtained was used in the next step without further purification.

¹H NMR(300MHz,CDCl₃)8.32(d,J＝8.9Hz,2H),8.26–8.15(m,2H),5.39–5.25(m,1H),4.78(dd,J＝12.9,3.1Hz,1H),4.52(dd,J＝12.9,6.4Hz,1H),4.46–4.35(m,2H),1.97–1.77(m,4H),1.77–1.49(m,2H)。

Step 3, (2R) -6-hydroxyhexane-1, 2-diyl dinitrate synthesis:

to a stirred solution of (5R) -5, 6-di (nitrooxy) hexyl 4-nitrobenzoate (prepared in step 2) (6.8g,18.2mmol) in 1/1 ethanol/THF (30mL each) mixture at 0 deg.C was added 2M sodium hydroxide solution (9.1mL,2eq) and the reaction was stirred for 2 hours. The reaction solution was diluted with ethyl acetate and water (100mL each) and extracted. The organic layer was washed successively with water and brine, dried over sodium sulfate and evaporated. The oily residue was purified by column chromatography (SNAP100, gradient system from 4/6 ethyl acetate/n-hexane to 60/40 ethyl acetate/n-hexane) to give the title compound as a colorless oil (3.50g, 86%).

¹H NMR(300MHz,CDCl₃)5.32(qd,J＝6.7,3.0Hz,1H),4.77(dd,J＝12.9,3.0Hz,1H),4.49(dd,J＝12.9,6.6Hz,1H),3.68(d,J＝5.5Hz,2H),1.89–1.71(m,2H),1.70–1.48(m,5H),1.46(s,1H)。

Step 4 Synthesis of (R) -5, 6-bis (nitrooxy) hexyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butyrate

To a stirred solution of 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) butanoic acid (237 mg; 0.95mmol) (prepared as described in example 1, steps 1 and 2) and (2R) -6-hydroxyhexane-1, 2-diyl dinitrate (prepared in step 3) (213 mg; 0.95mmol) in DCM (5ml) cooled to 0 deg.C was added EDAC (162 mg; 1.04mmol) and a catalytic amount of DMAP. The reaction was stirred at 0 ℃ overnight. The crude product was then washed with water, HCl 1N, water and brine, dried and evaporated in vacuo. The crude product was purified by flash chromatography [ Cy/EtOAc: 0% to 20% (1CV), 20% to 40% (7CV), 40% to 60% (2CV) ] to yield 338mg of the title compound as a yellow oil (yield: 78.2%).

¹H NMR(300MHz,CDCl₃)5.30–5.21(m,1H),4.74(dd,J＝12.9,3.0Hz,1H),4.47(dd,J＝12.9,6.5Hz,1H),3.99(t,J＝6.3Hz,2H),2.98(s,2H),2.16(d,J＝7.2Hz,3H),1.96(s,6H),1.81–1.69(m,2H),1.66–1.56(m,2H),1.52–1.31(m,8H)。α_D ²⁰＝+2.3(0.47％MeOH)

Example 14

Synthesis of (S) -5, 6-bis (nitrooxy) hexyl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate (Compound 17; the (S) -isomer of Compound 11)

Step 1 Synthesis of 2, 3-dimethoxy-5-methylbenzene-1, 4-diol

Reacting NaBH₄(5.2 g; 137.2mmol) are dissolved in 150ml of water and 2, 3-dimethoxy-5-methylcyclohexa-2, 5-diene-1, 4-dione (Sg; 27.4mmol) in 75ml of Et are added with stirring at room temperature₂O and 38ml MeOH. After 15 minutes, the mixture was placed in a separatory funnel and the layers were separated. The ether phase was removed and the aqueous phase was extracted twice with 50ml portions of ether. The combined organic extracts were washed with brine and dried over sodium sulfate. The solvent was removed under reduced pressure to give the title compound (9 g; 88%) as a red oil. It was used in the next step without further purification.

Step 2 Synthesis of 6-hydroxy-7, 8-dimethoxy-4, 4-dimethylchroman-2-one

2, 3-dimethoxy-5-methylbenzene-1, 4-diol (obtained in step 2) (9 g; 49mmol), methyl 3-methylbut-2-enoate (7 mL; 58mmol) and methanesulfonic acid (80mL) were heated at 70 ℃ for 90 minutes with stirring. The mixture was then poured into ice, diluted to 600ml with water and extracted with ether (3 × 150 ml). The combined organic layers were washed with brine, dried over sodium sulfate and concentrated to dryness to give a brown solid which was crystallized from methanol to give the pure title compound as yellow crystals (6.5 g; 50%).

Step 3 Synthesis of 4-Nitrophenyl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate

A similar synthesis to that described in Carpino et al, J.org.chem.,1989,54, 3303-propanoic acid 3310 was employed, but since 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyric acid was proven to be highly unstable (although it is described in the article), it was converted in situ to its 4-nitrophenyl ester.

A solution of the lactone from step 3 (2 g; 7.51mmol) in DMF (15mL) was added to a stirred solution of PDC (12.7 g; 33.7mmol) in DMF (15mL) at room temperature and stirring was continued for 4 hours. The mixture was diluted with water to 300mL and extracted rapidly with ether (3 × 150 mL). The combined organic extracts were washed with brine, dried over sodium sulfate and concentrated to about 10 mL. The solution was diluted in EtOAc (40mL) and then p-nitrophenol (1.57 g; 11.2mmol), DCC (2.31 g; 11.2 mmol; 1.5eq.) and DMAP (catalytic amount) were added in that order. The mixture was stirred at room temperature for 16 hours, then concentrated to dryness. Chromatographic purification on neutral alumina (eluent: cyclohexane/AcOEt 8/2) gave the title compound as an orange oil (800 mg; 26%).

¹H NMR(300MHz,CDCl₃)8.24(d,2H),7.20(d,2H),3.93(s,3H),3.89(s,3H),3.32(s,2H),2.19(s,3H),1.55(s,3H),1.53(s,3H)。

Step 4 Synthesis of (S) -5, 6-bis (nitrooxy) hexyl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate

178.0mg (0.45mmole) of 4-nitrophenyl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate (obtained in step 4) and 111.0mg (0.50mmole) (S) -6-hydroxyhexane-1, 2-diyl dinitrate (obtained in example 12, step 2) were added to DCM (1.5ml) in a 50-ml single-necked flask. After 10 minutes, 55.0mg (0.45mmole) of DMAP were added. The solution was stirred at room temperature for 18 hours. The reaction solution was washed with water and MgSO₄Dried, filtered and concentrated under reduced pressure to give a red oil in quantitative yield. The resulting red oil was purified by automated silica gel column chromatography eluting with a Cy/DCM/MeOH (50/50/0-68/30/2) mixture to give 200mg (91% yield) of the title compound as an orange oil.

MS:m/z＝489[M+H]⁺

TLC:(Cy/DCM/MeOH 68:30:2)R_f＝0.33

NMR(CDCl₃):5.25(m,1H),4.74(dd,1H),4.50(dd,1H),4.0(t,2H),3.97(s,3H),3.93(s,3H),3.0(s,2H),2.14(s,3H),1.8-1.5(m,6H),1.43(s,6H)。

Example 15

Synthesis of (S) -5, 6-bis (nitrooxy) hexyl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate (Compound 17)

The title compound was prepared as follows:

step 1 Synthesis of 2, 5-dioxopyrrolidin-1-yl 3- (4, 5-dimethoxy-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate

Using a synthesis similar to that described in Carpino et al, J.org.chem.,1989,54, 3303-propanoic acid 3310, 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyric acid was shown to be highly unstable (although it is described in the article), and was thus converted in situ to its N-hydroxysuccinimidyl ester.

A solution of the lactone from step 3 of example 14 (2.5 g; 9.39mmol) in DMF (20mL) was added at room temperature to a stirred solution of PDC (14.8 g; 39.4mmol) in DMF (20mL) and stirring was continued for 4 h. The mixture was diluted with water to 300mL and extracted rapidly with ether (3 × 150 mL). The combined ether extracts were washed with brine, dried over sodium sulfate and concentrated to about 10 mL. The solution was diluted in DCM (40mL) and NHS (1.29 g; 11.2mmol) and EDCl. HCI (2.16 g; 11.2mmol) were added successively and stirring was continued for 16 h. The mixture was diluted with water and extracted with DCM. The combined organic layers were washed with brine, dried over sodium sulfate and concentrated to dryness to give the title compound as an orange oil (2.74 g; 78%).

¹H NMR(300MHz,CDCl₃)3.97(s,3H),3.88(s,3H),3.28(s,2H),2.88(s,4H),2.16(s,3H),1.55(s,3H),1.57(s,3H)。

Step 2 Synthesis of (S) -5, 6-bis (nitrooxy) hexyl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate ester (Compound 17)

40.0mg (0.1mmole) of 2, 5-dioxopyrrolidin-1-yl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate, 28.0mg (0.12mmole) (S) -6-hydroxyhexane-1, 2-diyl dinitrate (prepared in step 2 of example 12) and DMF (1ml) were mixed together with stirring. After 10 minutes, 19.0mg (0.1mmole) of EDC HCl and 12.0mg (0.1mmole) of DMAP were added. The solution was stirred for 5 hours to 50 ℃. Using the reaction solutionWashing with water, and MgSO₄Dried, filtered and concentrated under reduced pressure to give a red oil in quantitative yield. The resulting red oil was purified by automated column chromatography over a silica gel Versaflash short column, eluting with a Cy/DCM/MeOH (50/50/0-68/30/2) mixture to give 14.6mg (31% yield) of the title compound as an orange oil.

MS:m/z＝489[M+H]⁺

TLC:(Cy/DCM/MeOH 68:30:2)R_f＝0.33

NMR(CDCl₃):5.25(m,1H),4.74(dd,1H),4.50(dd,1H),4.0(t,2H),3.97(s,3H),3.93(s,3H),3.0(s,2H),2.14(s,3H),1.8-1.5(m,6H),1.43(s,6H)。

Example 16

IOP-lowering activity in hypertonic saline-induced intraocular pressure (IOP) increases in rabbits

This study evaluated the intraocular pressure lowering effect of a single application of compound (1) at two different concentrations (1% and 0.3%) in rabbits with experimental intraocular pressure increase.

Adult male New Zealand white rabbits with a body weight of 1.8-2.0Kg were used in the experiment.

Transient increases in intraocular pressure were induced by injecting 0.1ml of hypertonic saline solution (5%) on both sides of the vitreous (Krauss et al, 2011, Orihashi et al, 2005).

Intraocular pressure was measured with a Tono-Pen XL before injection of hypertonic saline (basal value) and after 30, 60, 120 and 240 minutes of injection. Immediately after injection of hypertonic saline, vehicle (5% Cremophor-EL; 0.3% DMSO,0.2mg/ml benzalkonium chloride in PBS, pH 6.0) or compound was instilled as eye drops. The eyes were randomly assigned to different treatment groups. The vehicle and compound are infused directly into the conjunctival sac at the desired dose. Immediately prior to each set of pressure measurements, a drop of 0.4% oxybuprocaine hydrochloride (Novesine, Sandoz) was instilled in each eye.

The results are reported in table 3 and are expressed as the change in intraocular pressure (60 and 120 minutes after topical administration) relative to the vehicle and relative to the base intraocular pressure prior to injection of hypertonic saline.

Example 17

IOP-lowering activity in hypertonic saline-induced intraocular pressure (IOP) increases in rabbits

This study evaluated the effect of a single application of compound (15) (example 12) and ISMN (isosorbide-5-mononitrate) used as a reference compound in lowering intraocular pressure in an animal model of elevated intraocular pressure.

Adult male New Zealand white rabbits with a body weight of 1.8-2.0Kg were used in the experiment.

Animals were anesthetized with 20mg/ml/kg sodium pentobarbital. An increase in intraocular pressure was induced by injecting 0.1ml of hypertonic saline solution (5%) on both sides of the vitreous (Krauss et al, 2011, Orihashi et al, 2005).

Intraocular pressure was measured with Tono-PenXL before injection of hypertonic saline (basal value) and after 30, 60, 90, 120, 240 and 360 minutes of injection. Immediately after injection of hypertonic saline, vehicle (5% Cremophor-EL; 0.3% DMSO; 0.2mg/ml benzalkonium chloride in PBS, pH 6.0) or test compound was instilled as eye drops. The eyes were randomly assigned to different treatment groups. The vehicle or compound is infused directly into the conjunctival sac at the desired dose. Immediately prior to each set of pressure measurements, one drop of 0.2% oxybuprocaine hydrochloride (Novesine, Sandoz) diluted 1:1 with saline was instilled in each eye.

The results are reported in table 4 and are expressed as the change in intraocular pressure relative to the vehicle and relative to the base intraocular pressure prior to injection of hypertonic saline (30 and 60 minutes after topical administration).

A single application of compound (15) resulted in significantly more reduction of intraocular pressure than in the ISMN treated group.

Claims (18)

1. A compound of formula (I)

Or a stereoisomer thereof, wherein:

R₁selected from H, methyl, methoxy;

R₂is H or methyl;

R₃selected from H, methyl, methoxy;

or R₁And R₃Together form-CH ═ CH-;

R₄and R₅Is a methyl group and n is 1,

m is an integer from 1 to 10;

p is 0 or 1;

R₆is H or methyl.

2. A compound of formula (I) according to claim 1, wherein:

R₂is methyl;

R₄and R₅Is methyl and n is 1.

3. A compound of formula (I) according to claim 2, wherein:

R₁and R₃Is methyl.

4. A compound of formula (I) according to claim 2, wherein:

R₁and R₃Is methoxy.

5. A compound of formula (I) according to claim 2, wherein: r₁And R₃Together form-CH-.

6. A compound of formula (I) according to claim 2, wherein: r₁Is methyl and R₃Is methoxy.

7. A compound of formula (I) according to claim 2, wherein: r₁Is methoxy and R₃Is methyl.

8. A compound of formula (I) according to any one of claims 3 to 7, wherein p is 0 and R is₆Is H.

9. A compound of formula (I) according to any one of claims 3 to 7, wherein p is 1.

10. A compound of formula (I) according to claim 1, selected from:

4- (nitrooxy) butyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 1);

6- (Nitroxy) hexyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 2);

4- (nitrooxy) butyl 3-methyl-3- (3-methyl-1, 4-dioxo-1, 4-dihydronaphthalen-2-yl) butanoate (compound 4);

(5S,6R) -5, 6-bis (nitrooxy) heptyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate ester (Compound 8);

5, 6-bis (nitrooxy) hexyl-3-methyl 3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 10)

5, 6-bis (nitrooxy) hexyl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate (Compound 11)

4- (Nitropoxy) butyl 3- (4, 5-dimethoxy-2-methyl-3, 6-dioxocyclohexa-1, 4-dienyl) -3-methylbutyrate (Compound 12)

(S) -5, 6-bis (nitrooxy) hexyl 3-methyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohexa-1, 4-dienyl) butanoate (Compound 15)

And stereoisomers thereof.

11. Use of a compound of formula (I) according to any one of claims 1 to 10 for the preparation of a medicament.

12. Use of a compound of formula (I) according to any one of claims 1 to 10 for the preparation of a medicament for the treatment of ocular hypertension glaucoma, normal tension glaucoma, secondary glaucoma and ocular hypertension.

13. Use of a compound of formula (I) according to any one of claims 1 to 10 for the preparation of a medicament for the treatment of age-related macular degeneration, diabetic retinopathy, macular degeneration, inflammatory retinopathy, uveitis.

14. Ophthalmic composition comprising a compound of formula (I) according to any one of claims 1 to 10 and at least one ophthalmically acceptable ingredient and/or ophthalmically acceptable carrier.

15. A composition comprising a compound of formula (I) according to any one of claims 1 to 10 and one or more further active ingredients selected from: an alpha adrenergic receptor agonist, a beta receptor blocker, a carbonic anhydrase inhibitor, a prostaglandin analog, a non-steroidal anti-inflammatory drug, or a steroidal anti-inflammatory drug.

16. The composition of claim 15 for use in the treatment of high tension glaucoma, normal tension glaucoma, secondary glaucoma and ocular hypertension.

17. The composition of claim 14 for use in the treatment of age-related macular degeneration, diabetic retinopathy, macular degeneration, inflammatory retinopathy, uveitis.

18. An ophthalmic composition comprising the composition of claim 15 and at least one ophthalmically acceptable ingredient and/or ophthalmically acceptable carrier.