HK1218295B - Method for preparation of 6-trifluoromethylpyridine-3-carboxylic acid derivatives from trifluoroacetylacetic acid - Google Patents

Description

Process for preparing 6-trifluoromethylpyridine-3-carboxylic acid derivatives from trifluoroacetoacetic acid

Technical Field

The invention discloses a method for preparing 6-trifluoromethylpyridine-3-carboxylic acid derivatives from trifluoroacetoacetic acid and orthoesters, and the use thereof for preparing pharmaceutical, chemical and agrochemical products.

Background

2-trifluoromethylpyridine and 6-trifluoromethylpyridine-3-carboxylic acid derivatives are intermediates for the preparation of biologically active compounds. For example, WO 00/39094 a1 discloses trifluoromethylpyridines as herbicides, WO 2006/059103 a2 discloses trifluoromethylpyridines as intermediates in the preparation of pharmaceutical, chemical and agrochemical products, WO 2008/013414 a1 discloses trifluoromethylpyridines as vanilloid receptor antagonists and WO 2012/061926 a1 describes trifluoromethylpyridines as calcium channel blockers.

The general route for the preparation of 6-trifluoromethylpyridine-3-carboxylic acid derivatives was first reported by Okada et al in Heterocycles 1997, 46, 129-132 and was only slightly modified by others. The general synthetic strategy is outlined in scheme 1:

this route has disadvantages for large scale preparation of 6-trifluoromethylpyridine-3-carboxylic acid derivatives because ethyl vinyl ether is highly flammable and therefore difficult to handle, and because trifluoroacetylated enol ether and trifluoroacetylated enamine intermediates are unstable and cannot be stored for extended periods of time. In addition, most vinyl ethers are mutagenic.

Volochnyuk et al Synthesis 2003, 10, 1531-1540 discloses a process for the preparation of pyridines substituted in the 4-position by a trifluoromethyl residue. The pyridine is part of a bicyclic heterocycle. The process starts from an aminopyrazole which is reacted with trifluoroacetyl ketone or with the ethyl ester of trifluoroacetyl acetic acid. Said process is in principle not applicable for the preparation of the desired 6-trifluoromethylpyridine-3-carboxylic acid derivatives of the present invention, since the 6-position in Volochnyuk is the inner ring linking the pyridine moiety of the bicyclic heterocycle of Volochnyuk with the pyrazole moietyAn atom. This publication is totally free fromUse of trifluoroacetoacetic acid is mentioned.

WO 2004/078729A1 discloses the preparation of compounds of the formula (Xa) from 4-methoxy-1, 1, 1-trifluorobut-3-en-2-one, especially made from vinyl ether;

and the use of 4-methoxy-1, 1, 1-trifluorobut-3-en-2-one for the preparation of compounds of formula (I-2) is disclosed in example P2, page 18.

The compounds of formula (Xa) and the compounds of formula (I-2) are intermediates for the preparation of herbicides.

Swarts, Bulletin de la class des Sciences, academye Royale deBelgique, 1926, 12, 721-.

There is a need for improved procedures for the preparation of 6-trifluoromethylpyridine-3-carboxylic acid derivatives.

This need is met by the method of the present invention outlined below.

R.w.leiby, j.org.chem.1985, 50, 2926-2929 discloses the reaction of anthranilic acid with an orthoester, whereby enamines structurally comparable to anthranilic acid are expected to react also with orthoesters and are no longer suitable for reaction with trifluoroacetoacetic acid to trifluoromethylpyridine.

Surprisingly, in mixtures comprising orthoesters, enamines and trifluoroacetoacetic acid, the formation of trifluoromethylpyridine is observed.

Compared to the prior art, the method of the invention offers a number of advantages: importantly, no vinyl ether, trifluoroacetated enol ether intermediate or a separate trifluoroacetated enamine intermediate is required, e.g. for use in the form of 4-ethoxy-1, 1, 1-trifluorobut-3-en-2-one, which in WO 2004/078729A1 is referred to as 1-ethoxy-3-oxo-4-trifluorobutene, which is the substance (3) in example P2 of WO 2004/078729A1, prepared from vinyl ethers, e.g. according to Moriguchi, J.org.Chem., 1995, 60, 3523-3528, as cited on page 16, lines 8-9 of WO 2004/078729A 1. Furthermore, the process of the invention reduces the number of synthesis steps compared to known procedures, thereby reducing the overall cost.

In the following text, the following meanings apply if not otherwise indicated:

atmospheric pressure is typically 1 bar, depending on weather;

alkyl means a straight-chain or branched alkyl group, and examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and the like;

cyclic alkyl or cycloalkyl groups include alicyclic, bi-alicyclic and tri-alicyclic residues; examples of "cycloalkyl" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, norbornyl, and adamantyl;

alkoxy means alkyl-O, i.e. a group obtained by removing oxygen-bound hydrogen from an aliphatic alcohol;

(alkoxy) alkoxy means an alkoxy group wherein the alkyl group is substituted with one additional alkoxy group; examples of (alkoxy) alkoxy groups include methoxymethoxy groups having the formula MeO-CH2-O-, 2- (methoxy) ethoxy groups having the formula MeO-CH2-CH2-O-, and 2- (cyclopropylmethoxy) ethoxy groups having the formula (C3H5) CH2-O-CH2-CH 2-O-;

ac acetyl;

tBu tert-butyl;

cyanuric chloride 2,4, 6-trichloro-1, 3, 5-triazine

DBU 1, 8-diazabicyclo [5.4.0] undec-7-ene;

DABCO 1, 4-diazabicyclo [2.2.2] octane;

DMF N, N-dimethylformamide;

DMA N, N-dimethylacetamide;

DMSO dimethyl sulfoxide;

dppf 1,1' -bis (diphenylphosphino) ferrocene

Halogen means F, Cl, Br or J, preferably F, Cl or Br;

hemiacetal refers to an adduct of an alcohol (e.g., methanol or ethanol with a ketone) or with an aldehyde; the hemi-carboxyaldehyde can also be obtained when water is added to the enol ether; for example, the hemiacetal of methanol with trifluoroacetone is F₃C-C(OH)(OCH₃)-CH₃；

A mixture of hexane isomers;

hydrates are adducts of water with ketones or with aldehydes, e.g. the hydrate of trifluoroacetone is F₃C-C(OH)₂-CH₃；

Lithium LDA diisopropylamide

NMP N-methyl-2-pyrrolidone;

sulfamic acid HO-SO₂-NH₂；

THF tetrahydrofuran;

trifluoroacetone 1,1, 1-trifluoropropan-2-one;

xylene 1, 2-dimethylbenzene, 1, 3-dimethylbenzene, 1, 4-dimethylbenzene, or a mixture thereof.

Disclosure of Invention

The subject of the present invention is a process for the preparation of the compounds of formula (I);

the method comprises the StepS (Steps 1);

step (StepS1) includes reaction (ReacS 1);

reaction (ReacS1) is the reaction of the compound of formula (II) with the compound of formula (III) and the compound of formula (IV);

the compound of formula (II) is selected from the group consisting of compounds of formula (II-1), compounds of formula (II-2), compounds of formula (IIa), and mixtures thereof;

r1 is selected from C_1-10Alkyl radical, C_3-8Cycloalkyl, C (O) -O-C_1-4Alkyl, CH ═ CH₂Benzyl, phenyl and naphthyl;

c of R1_1-10Alkyl is unsubstituted or substituted by 1,2, 3, 4 or 5 identical or different substituents selected from the group consisting of halogen, OH, O-C (O) -C_1-5Alkyl, O-C_1-10Alkyl, S-C_1-10Alkyl, S (O) -C_1-10Alkyl, S (O)₂)-C_1-10Alkyl, O-C_1-6alkylene-O-C_1-6Alkyl radical, C_3-8Cycloalkyl, and 1,2, 4-triazolyl;

the benzyl, phenyl and naphthyl radicals of R1 are, independently of one another, unsubstituted or substituted by 1,2, 3, 4 or 5 identical or different substituents from the group consisting of halogen, C_1-4Alkoxy group, NO₂And CN;

y is selected from C_1-6Alkoxy radical,O-C_1-6alkylene-O-C_1-6Alkyl, NH₂NHR4 and N (R4) R5;

r4 and R5 are the same or different and are independently of each other C_1-6Alkyl, or together represent a tetramethylene or pentamethylene chain;

r10 is selected from C_1-8Alkyl radical, C_3-10A cycloalkyl group and a phenyl group,

said phenyl being unsubstituted or substituted by 1 or 2 identical or different substituents selected independently of one another from the group consisting of halogen, cyano, nitro, C_1-6Alkyl and phenyl;

r20 is selected from C_1-6Alkyl, O (CO) CH₃、O(CO)CF₃And OSO₃H。

Detailed Description

The compound of formula (II), the compound of formula (III) and the compound of formula (IV) are present in both step (StepS1) and reaction (ReacS1), so the reaction (ReacS1) is preferably carried out in a one-pot process, i.e. the reaction (ReacS1) is a one-pot reaction.

Preferably, R1 is selected from C_1-5Alkyl radical, C_3-6Cycloalkyl, C (O) -O-C_1-4Alkyl, CH ═ CH₂Benzyl and phenyl;

said C of R1_1-5Alkyl is unsubstituted or substituted by 1,2, 3, 4 or 5 identical or different substituents selected from the group consisting of halogen, OH, O-C (O) -CH₃、O-C_1-5Alkyl, S-C_1-5Alkyl, S (O) -C_1-5Alkyl, S (O)₂)-C_1-5Alkyl, O-C_1-4alkylene-O-C_1-4Alkyl radical, C_3-6Cycloalkyl and 1,2, 4-triazolyl;

the benzyl and the phenyl radical of R1 are, independently of one another, unsubstituted or substituted by 1,2, 3, 4 or 5 identical or different substituents selected from the group consisting of halogen, C_1-2Alkoxy, NO₂And CN;

more preferably, R1 is selected from the group consisting of methyl, ethyl, isopropyl, t-butyl, cyclopropyl, trifluoromethyl, difluoromethyl, chloromethyl, bromomethyl, C (O) -O-CH₃、C(O)-O-C₂H₅、CH₂-O-C(O)-CH₃、CH₂-O-CH₃、CH₂-S-CH₃、CH₂-S(O₂)-CH₃、CH₂-CH₂-O-CH₃、CH₂-O-CH₂-CH₂-O-CH₃、CH₂-O-CH₂-CH₂-O-CH₂-CH₃、CH＝CH₂And a phenyl group.

Even more preferably, R1 is selected from methyl, ethyl, chloromethyl, bromomethyl, CH₂-O-C(O)-CH₃And CH₂-O-CH₂-CH₂-O-CH₃；

In particular, R1 is selected from methyl, chloromethyl and CH₂-O-CH₂-CH₂-O-CH₃。

Preferably, Y is selected from C_1-6Alkoxy, NHR4 and N (R4) R5;

r4 and R5 are the same or different and are independently of each other C_1-6Alkyl, or together represent a tetramethylene or pentamethylene chain;

more preferably, Y is selected from methoxy and ethoxy.

Preferably, R10 is selected from C_1-8Alkyl radical, C_3-10A cycloalkyl group and a phenyl group,

said phenyl being unsubstituted or substituted by 1 or 2 identical or different substituents which are, independently of one another, selected from the group consisting of halogen, cyano, nitro and C_1-6An alkyl group;

more preferably, R10 is selected from C_1-8Alkyl radical, C_3-10A cycloalkyl group and a phenyl group,

said phenyl being unsubstituted or substituted by 1 or 2Identical or different substituents are substituted, independently of one another, from the group consisting of halogen and C_1-6An alkyl group;

even more preferably, R10 is selected from C_1-6Alkyl radical, C_3-6Cycloalkyl and phenyl;

in particular, R10 is selected from C_1-4An alkyl group;

more particularly, R10 is methyl or ethyl.

Preferably, R20 is selected from C_1-4Alkyl, O (CO) CH₃、O(CO)CF₃And OSO₃H；

More preferably, R20 is selected from methyl, ethyl, O (CO) CH₃、O(CO)CF₃And OSO₃H；

Even more preferably, R2 is methyl or ethyl.

Preferably, the compound of formula (II) is selected from the group consisting of compounds of formula (II-1), compounds of formula (II-2) and mixtures thereof.

Preferably, [ the compound of formula (II): the compound of formula (III) ] is in a molar ratio of [1:0.9] to [1:100], more preferably [1:0.9] to [1:10], even more preferably [1:0.9] to [1:5], especially [1:0.9] to [1:2.5 ].

Preferably, [ the compound of formula (II): the compound of formula (IV) is in a molar ratio of [20:1] to [1:20], more preferably [10:1] to [1:10], even more preferably [10:1] to [1:5], especially [10:1] to [1:3 ].

The reaction (ReacS1) may be carried out in a solvent;

preferably, the solvent is solvent (SolvS1) and solvent (SolvS1) is preferably selected from the group consisting of ethyl acetate, butyl acetate, dichloromethane, chloroform, acetonitrile, propionitrile, DMF, DMA, DMSO, sulfolane, THF, 2-methyl-THF, 3-methyl-THF, dioxane, 1, 2-dimethoxyethane, toluene, benzene, chlorobenzene, nitrobenzene, and mixtures thereof;

more preferably, the solvent (SolvS1) is selected from the group consisting of ethyl acetate, butyl acetate, dichloromethane, acetonitrile, propionitrile, DMF, DMA, sulfolane, THF, 2-methyl-THF, 3-methyl-THF, dioxane, 1, 2-dimethoxyethane, toluene, benzene, chlorobenzene, and mixtures thereof;

even more preferably, the solvent (SolvS1) is selected from the group consisting of ethyl acetate, butyl acetate, dichloromethane, acetonitrile, DMF, DMA, dioxane, 1, 2-dimethoxyethane, toluene, chlorobenzene, and mixtures thereof.

Preferably, the weight of solvent (SolvS1) is from 0.1 to 100 times, more preferably from 1 to 50 times, even more preferably from 1 to 25 times the weight of the compound of formula (II).

The reaction (ReacS1) may be carried out in the presence of an acid;

preferably, the acid is compound (AddS 1);

the compound (AddS1) is selected from the group consisting of acetic acid, propionic acid, trifluoroacetic acid, trichloroacetic acid, dichloroacetic acid, sulfuric acid, hydrochloric acid, acetic anhydride, acetyl chloride, toluenesulfonic acid, camphorsulfonic acid, methanesulfonic acid, and mixtures thereof;

preferably, the compound (AddS1) is selected from the group consisting of acetic acid, propionic acid, trifluoroacetic acid, trichloroacetic acid, sulfuric acid, hydrochloric acid, acetic anhydride, toluenesulfonic acid, methanesulfonic acid, and mixtures thereof;

more preferably, the compound (AddS1) is selected from the group consisting of acetic acid, trifluoroacetic acid, trichloroacetic acid, sulfuric acid, hydrochloric acid, acetic anhydride, methanesulfonic acid, and mixtures thereof;

even more preferably, the compound (AddS1) is selected from the group consisting of acetic acid, trifluoroacetic acid, trichloroacetic acid, sulfuric acid, and mixtures thereof.

Preferably, [ the compound of formula (II): the compound (AddS1) ] is in a molar ratio of [1:0.001] to [1:100], more preferably [1:0.01] to [1:10], even more preferably [1:0.05] to [1:5], especially [1:0.05] to [1:2], more especially [1:0.05] to [1:1], even more especially [1:0.05] to [1:0.5 ].

Preferably, the reaction temperature of the reaction (ReacS1) is from 50 to 250 ℃, more preferably from-20 to 180 ℃, even more preferably from 0 to 150 ℃, especially from 10 to 150 ℃, more especially from 50 to 120 ℃.

Preferably, the reaction (ReacS1) is carried out at a pressure of from atmospheric to 20 bar, more preferably from atmospheric to 15 bar, even more preferably from atmospheric to 10 bar.

Preferably, the reaction time of the reaction (ReacS1) is from 30 minutes (min) to 96 hours (h), more preferably from 45min to 48h, even more preferably from 45min to 36h, especially from 45min to 24h, more especially from 1h to 24 h.

After reaction (ReacS1), the compound of formula (I) may be isolated by any conventional method.

Preferably, the compound of formula (I) is isolated after the reaction (ReacS1) by hydrolysis and acidification of the mixture obtained from the reaction (ReacS 1).

The hydrolysis and acidification is preferably carried out by adding a compound (InAcS1), which is an aqueous mineral acid (InAcS1), preferably a compound (InAcS1) selected from aqueous hydrochloric acid and aqueous sulfuric acid.

After hydrolysis and acidification, any solvent is removed, preferably by distillation (SolvS 1);

the compound of formula (I) is preferably extracted by extraction with a solvent (solvextr s1), preferably selected from the group consisting of ethyl acetate, isopropyl acetate, butyl acetate, toluene, chlorobenzene, dichloromethane, chloroform and mixtures thereof; after extraction the solvent is preferably removed by distillation (SolvExtrs 1).

Saponification may also be carried out by treating the reaction mixture from the reaction (ReacS1) or treating the crude product of formula (I) with an aqueous or methanolic NaOH or KOH solution, followed by purification of the compound of formula (I) by acidification with a solvent (SolvExtrS1) and extraction, preferably followed by removal of the solvent (SolvExtrS1) by distillation, to yield the compound of formula (I) wherein Y ═ OH.

The compounds of the formula (II) are known compounds and can be prepared by known methods or analogously thereto.

For example, the compound of formula (II-2) can be prepared by saponification of ethyl trifluoroacetoacetate as taught by F.Swarts, Bulletin de la Classedessciences, academy Royale de Belgique, 1926, 12, 721-725.

The compounds of formula (III) are commercially available or can be prepared by methods analogous to known methods.

The compounds of formula (IV) are known compounds and can be prepared by or analogously to known methods, for example as described in WO 2004/078729a 1.

Another subject of the invention is the use of compounds of formula (I) for the preparation of pharmaceutical, chemical or agrochemical products,

wherein the compound of formula (I) is as defined above, and also all of its preferred embodiments, wherein the compound of formula (I) is prepared according to the process as described above, and also all of its preferred embodiments.

Examples

Example 1: reaction (ReacS1)

Reacting a compound of the formula (II-2) (0.10g, 0.64mmol), DMF (0.5ml), a compound of the formula (IV-1) (74mg, 0.64mmol), a compound of the formula (III-1) (0.16ml, 0.96mmol) at 80 deg.C,

And a mixture of sulfuric acid (0.007ml, 0.13mmol) was stirred for 3 h. A sample of the reaction mixture was diluted with brine (3ml) and aqueous hydrochloric acid (1N, 2ml) and extracted with ethyl acetate (3 ml). After concentrating the extract under reduced pressure, by¹HNMR analysis showed the compound of formula (I-1).

¹H NMR(400MHz，d₆-DMSO)：2.78(s,3H)，3.91(s,3H)，7.89(d,J＝8Hz,1H)，8.44(d,J＝8Hz,1H)。

Example 2: reaction (ReacS1)

A mixture of the compound of the formula (II-2) (0.12g, 0.77mmol), toluene (0.5ml), the compound of the formula (IV-1) (113mg, 0.98mmol), the compound of the formula (III-1) (0.16ml, 0.96mmol) and trifluoroacetic acid (0.01ml, 0.13mmol) was stirred at 80 ℃ for 17 h. A sample of the reaction mixture was diluted with brine (3ml) and aqueous hydrochloric acid (1N, 2ml) and extracted with ethyl acetate (3 ml). After concentrating the extract under reduced pressure, by¹H NMR analysis showed the compound of formula (I-1).¹H NMR data are shown in example 1.

Example 3: reaction (ReacS1)

A compound of the formula (II-2) (0.169g, 1.08mmol), toluene (0.52ml), a compound of the formula (IV-2) (0.26mmol, prepared analogously to WO 2004/078729A1, example P2, were prepared at 80 ℃ in that a reaction mixture was taken and concentrated under pressure, which reaction mixture was obtained after cooling and contained ethyl 3-amino-4-methoxyethoxy-but-2-enoate, which is a compound of the formula (IV-2), and the residue thus obtained was used in the present example, the content of the compound of the formula (IV-2) in the residue being determined from the amount of the compound of the formula (IV-2) present in the residue¹H-NMR determination relative to the standard), a mixture of the compound of the formula (III-1) (0.40ml, 2.4mmol), and trifluoroacetic acid (0.01ml, 0.13mmol) was stirred for 18H. The mixture was diluted with aqueous hydrochloric acid (1N, 10ml), extracted with ethyl acetate (5ml 1 times, 2.5ml 2 times), the combined extracts washed with brine (5ml), dried (MgSO 2)₄) And is inConcentration was performed under reduced pressure to obtain the compound of the formula (I-2) (114mg) as an oil.

By means of an internal standard (4-nitrobenzaldehyde)¹H NMR quantitatively indicates a yield of 54% for the compound of formula (IV).

¹H NMR(400MHz,CDCl₃)：1.42(t,J＝7Hz,3H)，3.36(s,3H)，3.57(m,2H)，3.71(m,2H)，4.43(q,J＝7Hz,2H)，5.02(s,2H)，7.68(d,J＝8Hz,1H)，8.26(d,J＝8Hz,1H)。

Claims (9)

1. A process for the preparation of a compound of formula (I);

the method comprises the StepS (Steps 1);

step (StepS1) includes reaction (ReacS 1);

reaction (ReacS1) is the reaction of the compound of formula (II) with the compound of formula (III) and the compound of formula (IV);

the compound of formula (II) is selected from the group consisting of compounds of formula (II-1), compounds of formula (II-2), compounds of formula (IIa), and mixtures thereof;

r1 is selected from C_1-10Alkyl radical, C_3-8Cycloalkyl, C (O) -O-C_1-4Alkyl, CH ═ CH₂Benzyl, phenyl and naphthyl;

c of R1_1-10Alkyl is unsubstituted or substituted by 1,2, 3, 4 or 5 identical or different substituents selected from the group consisting of halogen, OH, O-C (O) -C_1-5Alkyl, O-C_1-10Alkyl, S-C_1-10Alkyl, S (O) -C_1-10Alkyl, S (O)₂)-C_1-10Alkyl, O-C_1-6alkylene-O-C_1-6Alkyl radical, C_3-8Cycloalkyl and 1,2, 4-triazolyl;

the benzyl, phenyl and naphthyl radicals of R1 are, independently of one another, unsubstituted or substituted by 1,2, 3, 4 or 5 identical or different substituents from the group consisting of halogen, C_1-4Alkoxy group, NO₂And CN;

y is selected from C_1-6Alkoxy, O-C_1-6alkylene-O-C_1-6Alkyl, NH₂NHR4 and N (R4) R5;

r4 and R5 are the same or different and are independently of each other C_1-6Alkyl, or together represent a tetramethylene or pentamethylene chain;

r10 is selected from C_1-8Alkyl radical, C_3-10A cycloalkyl group and a phenyl group,

said phenyl being unsubstituted or substituted by 1 or 2 identical or different substituents selected independently of one another from the group consisting of halogen, cyano, nitro, C_1-6Alkyl and phenyl;

r20 is selected from C_1-6Alkyl, O (CO) CH₃、O(CO)CF₃And OSO₃H。

2. The method of claim 1, wherein

The reaction (ReacS1) was carried out in a one-pot procedure.

3. The method of claim 1 or 2, wherein

R1 is selected from C_1-5Alkyl radical, C_3-6Cycloalkyl, C (O) -O-C_1-4Alkyl, CH ═ CH₂Benzyl and phenyl;

said C of R1_1-5Alkyl is unsubstituted or substituted by 1,2, 3, 4 or 5 identical or different substituents selected from the group consisting of halogen, OH, O-C (O) -CH₃、O-C_1-5Alkyl, S-C_1-5Alkyl, S (O) -C_1-5Alkyl, S (O)₂)-C_1-5Alkyl, O-C_1-4alkylene-O-C_1-4Alkyl radical, C_3-6Cycloalkyl and 1,2, 4-triazolyl;

said benzyl and said phenyl of R1 are independently from each other unsubstituted or substituted by 1,2, 3, 4 or 5 identical or different substituents selected from the group consisting of halogen, C_1-2Alkoxy group, NO₂And CN.

4. The method of claim 1 or 2, wherein

Y is selected from C_1-6Alkoxy, NHR4 and N (R4) R5;

r4 and R5 are the same or different and are independently of each other C_1-6Alkyl or together represent a tetramethylene or pentamethylene chain.

5. The method of claim 1 or 2, wherein

R10 is selected from C_1-8Alkyl radical, C_3-10A cycloalkyl group and a phenyl group,

said phenyl being unsubstituted or substituted by 1 or 2 identical or different substituents which are, independently of one another, selected from the group consisting of halogen, cyano, nitro and C_1-6An alkyl group.

6. The method of claim 1 or 2, wherein

R20 is selected from C_1-4Alkyl, O (C)O)CH₃、O(CO)CF₃And OSO₃H。

7. The method of claim 1 or 2, wherein

The compound of formula (II) is selected from the group consisting of compounds of formula (II-1), compounds of formula (II-2), and mixtures thereof.

8. The method of claim 1 or 2, wherein

The reaction (ReacS1) was carried out in a solvent;

the solvent is solvent (SolvS1) and solvent (SolvS1) is selected from the group consisting of ethyl acetate, butyl acetate, dichloromethane, chloroform, acetonitrile, propionitrile, DMF, DMA, DMSO, sulfolane, THF, 2-methyl-THF, 3-methyl-THF, dioxane, 1, 2-dimethoxyethane, toluene, benzene, chlorobenzene, nitrobenzene, and mixtures thereof.

9. The method of claim 1 or 2, wherein

The reaction (ReacS1) is carried out in the presence of an acid and the acid is compound (AddS 1);

the compound (AddS1) is selected from the group consisting of acetic acid, propionic acid, trifluoroacetic acid, trichloroacetic acid, dichloroacetic acid, sulfuric acid, hydrochloric acid, acetic anhydride, acetyl chloride, toluenesulfonic acid, camphorsulfonic acid, methanesulfonic acid, and mixtures thereof.