NO802177L - PROCEDURE FOR THE INTRODUCTION OF OXYGENIC FUNCTIONAL GROUPS IN ANSAMYSINES - Google Patents

Description

The invention primarily relates to introduction

of an oxygen-containing functional group in the ansamycin molecule, namely a free etherified or esterified hydroxyl group in the 3-position of rifamycin-type ansamycins.

As it has been found, compare European Patent Application No. 80810016.8, is; it : in a fermentative way, produced 3-hydroxyrofamycin-S favorably anitbiotic, especially antimicrobial properties corresponding to the nature of these rifamycin-S.

In the search for an alternative pure chemical access to this compound, a procedure was now found-

one according to the invention which in a surprisingly simple way not only manages to give the desired previously known 3-hydroxyfamycin-S, but also includes access to a wide group of new rifamycin analogues, which are distinguished by a hitherto unknown structure: - ,. namely a free, etherified or esterified hydroxyl group in the 3-position.

The end substances obtainable according to the method are in particular compounds with formula

in which R and R<1> each means a hydrogen atom or R' means acetyl and R hydrogen., an optionally substituted hydrocarbyT" or the acyl residue of a carboxylic acid, as well as the corresponding rifamycin-S derivatives with 1, 4--hydroquin6n- stroll.

Because of the very narrow ratio between the 1,4-quinone and -hydroquinone forms. (corresponding to rifamycin-S and SV) and the simplicity with which the two forms merge into each other, it is wherever not specifically stated otherwise, including both forms.

The hydrocarbyl residue (hydrocarbon residue) is an acyclic, carbocyclic or carbocyclic-acyclic hydrocarbon residue which preferably has a maximum of 18 carbon atoms, and can be saturated or unsaturated, unsubstituted or substituted.

It can also replace one with two or more carbon atoms

have heteroatoms, such as oxygen, sulfur and nitrogen in particular,

but also phosphorus and silicon and thus form a heterocyclic residue (heterocyclyl residue) or a heterocyclic-acyclic residue.

Unsaturated residues are those which contain single or multiple bonds such as double and triple bonds. Cyclic residues, in which at least one 6-membered carbocyclic or 5- to 8-membered heterocyclic ring contains the maximum number of non-cumulative double bonds, are designated as aromatic. Carbocyclic residues in which at least one ring is present as a 6-membered aromatic ring (i.e. benzene ring) are referred to as aryl residues.

When nothing else is indicated, organic residues denoted by "lower" contain a maximum of 7, preferably a maximum of 4 carbon atoms.

An acyclic hydrocarbon radical is in particular a straight or branched lower alkyl, lower alkenyl, lower alkadienyl or lower alkynyl radical. Lower alkyl is e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, as well as n-pentyl, isopentyl, n-hexyl, isohexyl or n-heptyl, lower-alkenyl is e.g. vinyl, allyl, propenyl, isopropenyl, 2- or 3-methallyl and 2- or 3-butenyl, lower-alkenyl are e.g. propargyl or 2-butynyl.

A carbocyclic hydrocarbon radical is in particular a mono-, bi- or polycyclic cycloalkyl, cycloalkenyl or cycloalkadienyl radical or a corresponding aromatic ring-containing aryl radical. Preferred are Bester with a maximum of 12 ring carbon atoms and 3- to 8-, preferably 5- and/or 6-membered rings, 2ide.tf.de also can have one or more acyclic residues, e.g. the above, and especially the lower alkyl residues, or the further carbocyclic residues. Carbocyclic-acyclic residues are those where an acyclic residue, especially one with a maximum of 7, preferably a maximum of 4 carbon atoms,

has one or more carbocyclic,. possibly aromatic residues of the above definition. In particular, cycloalkyl-lower-alkyl and aryl-lower-alkyl residues, as well as their ring and/or side chain unsaturated analogues, are to be mentioned.

Cycloalkyl is e.g. cyclopropyl, cyclobutyl, cyclopentyl, cycloheptyl and cyclooctyl, as well as bicyclo/2,2,2/ octyl, 2 bicyclo/2,2,1/heptyl and adamantyl, further also

1-, or 3-methyl cyclopentyl, 4--tert.butylcyclob.hexyl, U> U-dimethylcyclohexyl, 2, 4.» 6-trimethylcyclohexyl and 2,4-»4-,6-tetramethyl cyclohexyl, cycloalkenyl is e.g. one of the already mentioned cycloalkyl residues, so.m has a double bond in 1-,

2-, or 3-position such as 1-,2- or 3-cyclopentenyl and 1-

2 or 3-cyclohexenyl. Cycloalkyl-lower-alkyl or -lower-alkenyl is e.g. cyclopropyl-, cyclopentyl-, cyclohexyl- or cycloheptyl-methyl, 1- or 2-ethyl resp. -vinyl, -1--2- or -3-propyl, resp. -allyl, further also dicyclohexyl-methyl and tricyclohexylmethyl, Cycloalkenyl-lower-alkyl or lower-alkenyl are e.g. 1-, 2- or 3-cyclopentenyl- or 1-, 2- or 3-cyclohexenyl-methyl -1- or -2-ethyl, resp.

-vinyl, -1-, -2- or 3-propyl resp. -allyl.

An aryl residue is primarily a phenyl, further

a naphthyl such as 1- or 2-naphthyl, a biphenylyl, such as especially 4-biphenylyl, further also an anthryl, fluorenyl and azulenyl. Preferred aryl lower alkyl and lower alkenyl radicals are

e.g. phenyl-lower-alkyl or phenyl-lower-alkenyl, such as e.g. benzyl, 1- or 2-phenylethyl, 1-, 2- or 3-phenyl-propyl, diphenylmethyl (i.e. benzhydryl), trityl and 1- or 2-naphthylmethyl, resp. styryl or cinnamyl.

Heterocyclic residues including the heterocyclic-acyclic residues are particularly monocyclic but also bi- or polycyclic, aza-, tia-, oxa-, tiaza-, thiadiaza-, oxaza-, diaza-, triaza- or tetrazacyclic residues of an aromatic character, further corresponding partially or completely saturated heterocyclic residues of this type, with similar residues possibly e.g. as the aforementioned carbocyclic or aryl radicals may have further acyclic, carbocyclic or heterocyclic radicals, and mono-, di- or polysubstituted. The acyclic part in heterocyclic-acyclic residues has e.g. the meaning given for the corresponding carbocyclic-acyclic residues. In the first place, there are unsubstituted or substituted monocyclic, monoaza-, monothia- or monooxacyclic residues, such as aziridinyl, oxiranyl and triiranyl, and especially heterocyclic residues of an aromatic character, such as pyrryl, e.g. 2-pyrryl, or 3-pyrryl, pyridyl, e.g. 2-, 3- or 4-pyridyl, further thienyl, e.g. 2- or 3-thienyl, or furyl. e.g. 2-furyl, bicyclic monoaze-, monooxa- or mono-thiacyclic radicals, such as indolyl, e.g. 2- or 3-indolyl, quinolinyl, e.g. 2- or 4--quinolinyl., isoquinolinyl,

e.g. 1-isoquinolinyl, benzofuranyl, e.g. 2- or 3-benzofuranyl, or benzothienyl, e.g. 2- or 3-benzothienyl, monocyclic diaza-, triaza-, tetraza-, oxaza-, thiaza- or thiadiazacyclic radicals, such as imidazolyl, e.g. 2-imidazolyl, pyrimidinyl, e.g. 2_- .or 4--pyrimidinyl, triazolyl,

e.g. 1,2,4-triazoly3-yl, tetrazolyl, e.g. 1- or 5-tetrazolyl, oxazolyl, e.g. 2-oxazolyl, isoxazolyl, e.g. 3- or 4-isoxazolyl, thiazolyl, e.g. 2-thiazolyl, isothiazolyl, e.g. 3- or 4--isothiazolyl or 1,2,4-- or 1,3.4--thiadiazolyl, e.g. 1. 2. 4-thiadiazol-3-yl or 1,3»4-«-thia-diazol-2-yl, or bicyclic diaza-, oxaza- or thiazacyclic residues such as benzimidazolyl, e.g. 2-benzimidazolyl, benzozazolyl, e.g.: 2-benzoxazolyl, or benz thiazolyl,

e.g. 2-benzthiazolyl. Corresponding partially or completely saturated residues are e.g. tetrahydrothienyl, as 2-tetrahydrothienyl, tetrahydrofuryl, as 2-tetrahydrofuryl, pyrrolidyl,

12 3

as 2-pyrrolidyl, tetrahydropyridyl, as A-A - or A - piperideinyl, or piperidyl, as 2-, 3-» or 4--piperidyl, further also morpholinyl, thiomorpholinyl, piperazinyl and N,N'-Bis-lower-alkyl-piperazinyl, such as especially N,N<1->dimethylpiperazinyl. These residues may also have one or more acyclic, carbocyclic or heterocyclic residues, especially those mentioned above. Heterocyclic-acyclic residues are particularly de-

derived from cyclic residues with a maximum of 7, preferably a maximum of 4 carbon atoms, e.g. from the above, and may have a two or more heterocyclic residues,, e.g. the aforementioned.

As already mentioned, a hydrocarbyl (including a heterocyclyl) can be substituted with one, two or more similar or different substituents with the following substituents in particular being considered: free, etherified and esterified hydroxyl groups, mercapto- and lower-alkylthio- and optionally substituted phenylthio groups, halogen atoms, such as chlorine and fluorine, but also bromine and iodine, formyl-(i.e. aldehydo-) and keto groups, also as acetals, resp. ketals, azido and nitro groups, primary, secondary and preferably tertiary amino groups, by means of conventional protecting groups, protected by primary or secondary amino groups, such as suitable acylamino groups and diacylamino groups, further free and in salt form, as alkali metal salt form, present sulfamino groups, free and functionally modified carboxyl groups, such as carboxyl groups present in salt form or esterified, optionally one or two hydrocarbon residue-containing carbamoyl, ureidocarbonyl or guanidinocarbonyl groups and cyano groups, as well as optionally functionally modified sulfo groups such as sulfamoyl or sulfo groups present in salt form.

An etherified hydroxyl group present as a substituent in hydrocarbyl is e.g. a lower alkoxy group, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy and tert.butoxy, which may also be substituted. Thus, such a lower alkoxy group can be substituted with halogen atoms, especially in the 2-position, as in 2,2,2-trichloroethoxy-, 2-chloroethoxy- or 2-iodoethoxy acid residues, or with lower-alkoxy acid residues, especially in the 1-position, as in The 1-butoxy-ethoxy residue, or in the 2-position, as in the 2-methoxyethoxy residue. Furthermore, such etherified hydroxyl groups are also optionally substituted phenoxy acid residues and phenyl-lower-alkoxy acid residues, such as above all benzyloxy-, benzhydryloxy- and triphenylmethoxy- (tri-tyloxy-) residues, as well as heterocyclyloxy acid residues, which in particular

2-tetrahydrofuranyloxy and 2-tetrahydropyranyloxy esters.

In this context, etherified hydroxyl groups also mean silylated hydroxyl groups, such as e.g. exists in tri-lower-alkylsilyloxy-, such as trimethylsilyloxy- or dimethyl-tert-butylsilyloxy-, or phenyldi-lower-alkylsilyloxy- or lower-alkyl-diphenylsilyloxy groups.

A preferred hydroxyl group present as a substituent in hydrocarbyl is one in which the hydrogen atom of the hydroxyl group is replaced by a further acyl residue-COR 1 defined below, or a lactonized hydroxyl group.

An esterified carboxyl group present as a substituent in hydrocarbyl is one in which the hydrogen atom is replaced by one of the above-mentioned hydrocarbon residues, preferably a lower-alkyl or phenyl-lower-alkyl residue, as an example of an esterified carboxyl group, it is particularly worth mentioning methoxy , ethoxy, tert.butoxy or benzyloxycarbonyl group, as well as a lactonized carboxyl group.

A pr i mær gr uppe -NH^ as a substituent of hydrocar-' .:. byl is preferably present in a protected form, as an acyla:nino£ group corresponding to this group; with the formula -NH-Ac, in which Ac has the below characterized stated meaning. A secondary amino group has, instead of one of the two hydrogen atoms, a preferably unsubstituted hydrocarbon residue of the above-mentioned type, and is preferably in a protected form, as a derived acylamino group which additionally has a monovalent acyl residue Ac characterized below.

As the amino protecting group at the end of _acylr est Ac, derives preferably from a carboxylic acid half-derivative,

and is preferably an optionally especially with lower-alkyl, lower-alkyl, nitro and/or halogen, substituted lower-alkylcarbonyl or aryl-loweralkylcarbonyl, such as methoxycarbonyl, ethoxycarbonyl, tert. butoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, 2-iodoethoxycarbonyl, benzyloxycarbonyl, 2rphenyl-2-propoxycarbonyl, 2-p-tolyl-2-propoxycarbonyl, 2-p-biphenylyl-2-propoxycarbonyl, 1,1,-diphenylethoxycarbonyl or p,p'-dimethoxybenzhydryloxycarbonyl. Of particular note is also a 2-(trihydrocarbylsilyl)-ethoxycarbonyl, which

2-triphenylsilylethoxycarbonyl, 2(dibutyl-methyl-silyl)-ethoxycarbonyl and especially 2-trimethylsilylethoxycarbonyl, which are particularly easily cleavable and cleavable selectively with fluorides of quaternary bases.

A tertiary amino group occurring as a substituent in hydrocarbyl is characterized by the formula R 9, -N-R^,

wherein R cL and R, D mean monovalent hydrocarbon residues (including the analogous heterocyclic residues) which may be the same or different and correspond to the above characterized unsubstituted hydrocarbyl residue. The two hydrocarbon residues R^

and Rtø can be bound to each other by means of a carbon-carbon bond or an oxygen, sulfur or optionally substituted nitrogen atom, and together with the nitrogen atom in the amino group, a nitrogen-containing heterocyclic ring is formed. As examples of particularly preferred free amino groups, the following can be mentioned: Di-lower-alkylamino, such as dimethylamino, di-ethylamino, pyrrolidino, piperidino, morpholino, thiomorpholino and piperazino or 4--methylpiperazino, optionally with lower-alkyl, lower- alkoxy, halogen and/or nitro substituted diphenylamino and dibenzylamino, among the protected ones, then especially halogen-lower-alkoxycarbonylamino, such as 2,2,2-trichloroethoxy-carbonylamino, f en<y>l-lower-alkoxycarbonylamino, as 4-- methoxy-benzyloxycarbonylamino, as well as 2-(trihydrocarbylsilyl)-ethoxy-carbonylamino, such as 2-triphenylsilylethoxycarbonylamino, 2-(di-butyl-methyl-silyl)-ethoxycarbonylamino and 2-trimethylsilyl-ethoxycarbonylamino.

A carboxylic acid's acyl residue is characterized by

a partial formula R in C0-. In this formula, R can either mean hydrogen and thus form the formyl group, or have one of the above-mentioned general preferred meanings of the hydrocarbyl residue and thus derive from an optionally substituted acyclic, carbocyclic, carbocyclic-acyclic, heterocyclic or heterocyclic-acyclic carboxylic acid. Particularly preferred are acyl residues of the following monocarboxylic acid with a maximum of 18 carbon atoms: acyclic carboxylic acids, especially lower cancarboxylic acids such as propionic, butyric, isobutyric, valerian, isovalerian, caproic, trimethylacetic, oenant and diethylacetic

acid and above all acetic acid, more also corresponding halo-generated lower-alkane carboxylic acids, such as chloroacetic acid, bromoacetic acid or a-bromoisovaleric acid, carbocyclic or carbocyclic-acyclic monocarboxylic acids, e.g. cyclopropane-, cyclobutane-.; cyclopentane- and cyclohexane-carboxylic acid resp. cyclopropane, cyclobutane, cyclopentane or cyclohexane-acetic acid or propionic acid, aromatic carbocyclic carboxylic acids, e.g. benzoic acid which may be substituted one or more times by halogen, such as fluorine, chlorine, bromine and/or hydroxyl, lower alkoxy, lower alkyl and nitro, aryl or aryloxy lower alkanecarboxylic acids and their chain-unsaturated analogues , e.g. optionally as stated above for the benzoic acid, substituted phenylacetic resp. phenoxyacetic acids, phenylpropionic acids and cinnamic acids, and heterocyclic acids, e.g. furan-2-carboxylic acids, 5-tert-butylfuran-2-carboxylic acids, 5-bromofuran-2-carboxylic acids, thiophene-2-carboxylic acids, nicotinic or isonicotinic acids, 4-pyridinepropionic acids, and optionally with lower alkyl residues substituted pyrrole-2- or 3-carboxylic acids, further also corresponding α-amino acids, especially the naturally occurring amino acids from the L-series, e.g., gly-

cin, phenylglycine, proline, leucine, valine, tyrosine, histidine and asparagine, preferably in an N-protected form, i.e. in one in which the amino group is substituted with a normal one, e.g. one of the above-mentioned amino protecting groups. Among the carboxylic acids, those where R i means a hydrocarbyl, which is substituted with a possibly functionally modified carboxyl, i.e. derives from a dicarboxylic acid with a maximum of 12 carbon atoms, and which is the basis of one of the above-mentioned optionally substituted acyclic carbocyclic, carbocyclic-acyclic, heterocyclic and heterocyclic-acyclic residues. Examples include the following dicarboxylic acids: Oxalic acid, malonic acid, mono- or di-lower alkylmalonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, itaconic acid, citraconic acid, angelica acid, 1,1-cyclopentane or 1,1-cyclohexanedicarboxylic acid, one with halogen, such as fluorine, chlorine, or bromine and/or lower alkyl, lower alkoxy and nitro, optionally substituted phthal-, chino-

lin - or phenylsuccinic acid, as well as tartric acid, mesoxalic acid, oxalic acid, malic acid, tartaric acid, a tartaric acid esterified or esterified to the hydroxyl group, glutamic acid and aspartic acid; in that the two last-mentioned acids are preferably present with possessed amino groups. As already mentioned, other carboxyl groups cannot be present free, but also functionally modified, e.g. as an ester with an alcohol, or as a salt, preferably as a physiological hold-

bare salt, with a salt-forming basic component. In the first instance, metal or ammonium salts, such as alkali metal and alkaline earth metal, come into consideration. f. e.g. sodium, potassium, magnesium or calcium salts, resp. ammonium salts with ammonia or suitable organic amines. Among these, tertiary monoamines and heterocyclic bases, e.g. triethylamine, tri (2-hydroxyethyl')-amine, 1-ethyl-piperidine, as well as pyridine, collidine or quinoline.

The method according to the invention is characterized by that in 3-bromifamycin-S with formula

bromine is exchanged with the above-mentioned group OR, and the product is isolated in the form of a derivative of the S series or the SV series.

The exchange preferably takes place by treating the compound of formula (II) with a compound of formula ROH (III), in which R has the above-mentioned meaning, or a salt thereof in a neutral basic environment and optionally in the presence of a bromine-hydrogen binding agent and/or a organic solvent.

The practical implementation of the method according to the invention takes place under the usual general conditions for preparative organic chemistry: Normally, one works under atmospheric pressure or a slightly elevated pressure, e.g. with easily volatile solvents to achieve high reaction temperatures, these lie between room temperature and: the boiling temperature of the mixture, especially between approx. 20 to approx. 14-0°C, preferably between approx. 90 to approx. 125°C. Usually you have a surplus, e.g. about. 2 to 15 molar equivalents,

of exchange agents with formula (III) and possibly also of auxiliaries, and carrying out the reaction in a homogeneous or heterogeneous phase, i.e. o solution or suspension, in the latter case preferably under stirring. Normally, the reaction time extends over a period of approx. 30 minutes to approx. 1 day, which depends on the reaction temperature and other conditions, as well as on the specific properties of components (III-). The progress of the reaction can be checked with the usual analytical methods, especially wet spectroscopy and thin-layer chromatography.

Symbol R in the exchange reagent of formula ROH (III) may have any of the above general and preferred meanings. Starting substances of formula (II), i.e. 3-bromo-rifamycin-S are known.

As an aid for binding bromohydrogen, in principle desirable basic compounds can be used such as, on the one hand, organic nitrogen-containing bases, e.g. tertiary amines of the type triethylamine, ethylisopropylamine, N-ethyl-piperidine or N,N<1->dimethylpiperazine, or aromatic heterocyclic bases of the type pyridine, collidine or quinoline, on the other hand basic reacting:; inorganic compounds, especially alkali metal salts of weaker or medium strong acids, e.g. those further mentioned below, as well as analogous salts of carboxylic acids, further also ion exchangers such as cation exchangers in particular in the alkali metal cycle, such as Na or K cycle or anion exchangers in the OH cycle. Finally, at least partially for this purpose neutral treagers.en.déc nitrogen-containing compounds can serve, which at the same time are often also advantageous solvents, e.g. carboxylic acid amides, especially lower-aliphatic carboxylic acid amides such as formamide, N,N-dimethylformamide, acetamide and N,N-dimethylacetamide, and cyclic amides such as N-methylpyrrolidone, as well as amido derivatives of carboxylic acid, such as urethane. When choosing the specific agent, it is necessary to always take into account the great sensitivity of the irifamycin structure, and to avoid such agents that would lead to side reactions. The above basic compounds can serve to maintain the basic reaction of the environment, especially for this purpose the usual buffers can be used.

Thereby it is also to be noted that one and the same reaction component can also take over the function of another or more components, resp. h j elpe stojBf is, e.g. the reaction agent with formula (III) is used at the same time as the solvent, or a basic component not only serves to set the basic reaction, but binds by the buffering effect at the same time hydrogen bromide, and even as e.g. a metal salt of a carboxylic acid, besides these two functions, also forms the actual exchange agent (III).

Although the exchange reaction is always based on the same principle and the conversion takes place according to a uniform basic scheme, for an optimal result it is necessary in practical implementation to take into account the nature of the reaction components, primarily the reaction medium with formula (III ). According to the above definition of the residue R, the formula ROH (III) can mean water, an alcohol and an acid.

a salt thereof, i.e. compounds whose physical properties, e.g. solubility and miscibility as well as the general chemical relationship are often far from each other, and thus can significantly affect the course of the turnover according to the invention. Because of this circumstance, for any such type of connection, the preferred process conditions are particularly advantageous, and are specifically chosen.

If free hydroxyl (R=H) is to be introduced in the exchange according to the invention, the reaction is carried out in an aqueous environment, to improve the solubility conditions, an organic solvent can be added to the reaction mixture, e.g. alcohols, especially lower alkanols such as methanol, ethanol or isopropyl alcohol, or other water-miscible highly polar aprotic solvents of the type dimethylsulfoxide, dimethylformamide or hexamethylphosphoric triamide. The conversion takes place especially under weakly basic conditions, especially at a pH between 7.0 and 10.0, as the course of the conversion can be further controlled by a narrower selection of the pH value. If you work in pH - areas around 9»0, you get predominantly 25-0-desacetyl-3-hydroxy-rifamycin-S (I, R=R'=H), at a pH below approx. 8.0, on the other hand, the 25-stranded ester group is not attacked, and 3-hydroxyrifamycin-S is produced. To set the desired pH value, advantageous salts of alkali metals, such as sodium and potassium in particular, are used with weak or medium-strength inorganic or organic acids, especially those used for the preparation of buffer solutions, such as e.g. hydrocarbons, carbonates, primary, secondary and tertiary phosphates, acetates, benzoates, citrates and tartrates. These salts preferably simultaneously also serve as hydrogen bromide binding agent, provided that they are used in an amount that not only manages to neutralize the hydrogen bromide's acidity (where in itself one molar equivalent would be sufficient), but also manages to keep the pH within the desired range, preferably below this amount does not exceed two molar equivalents.

If simultaneous deacetylation in the 25-position is desired, sodium bicarbonate, sodium carbonate or potassium carbonate is preferably used, but if the 25-0-acetyl group is to be retained, sodium acetate or a suitable phosphate buffer is used in particular.

If, in the exchange according to the invention, a 3-ether group OR (R=hydrocarbyl) is to occur, then one works predominantly in excess reactant, i.e. in the corresponding alcohol ROH, which at the same time acts as a solvent, and in the absence of water. As bromine hydrogen binding agent, one can use one of the above, but above all an alkali metal salt of a carboxylic acid, such as sodium acetate in particular.

which then also gives the mixture the necessary weak basic reaction. In particular, however, it is only necessary to use a mini-template quantity not exceeding, approx. 2 molar equivalents of this aid, to keep side reactions, mainly the exchange of bromine for acetoxy groups within limits.

If, in the exchange according to the invention, an esterified 3-hydroxyl group OCOR 1 is to be introduced, the exchange agent is preferably an alkali metal salt of the carboxylic acid R COOH, which is to be introduced, above all the sodium salt which is especially used in excess, i.e. an amount of at least 2 molar equivalents (as mentioned above, thereby the reagent simultaneously binds the developed hydrogen bromide and gives the mixture the weak basic reaction): However, one can also an-

reverse a free acid and May its salt transiently occur directly in the reaction mixture by means of an equivalent amount of an alkali metal hydrocarbonate or carbonate. An anhydrous aprotic polar solvent is preferably used as a solvent, such as a lower alkanoic acid amine, e.g. N,N-dimethylacetamide, N,N-diethylacetamide and, above all, N,N-dimethylformamide-, a dislaver-alkylsulfoxide, such as dimethylsulfoxide, or hexamethylphosphoric triamide.

The starting substances with the formula ROH are known compounds or available analogously to these by known methods.

In the primary reaction mixture, both oxidation steps of the final substance are usually present next to each other, i.e. the 1,4-quinone form of the S series and the 1,4-hydroquinone form of the SV series. However, expediently, the overall product is isolated in only one of the two forms, preferably in quinone forms. For this purpose, the crude reaction mixture is treated with an oxidizing agent, especially one that is common for the oxidation of known hydroquinones, e.g. ammonium persulphate, hydrogen peroxide, air oxygen or preferably potassium ferricyanide, the oxidation takes place especially under basic conditions. If one wishes to isolate the final product, the hydroquinone form (as a rifamycin-SV derivative), the crude reaction mixture is treated with a common quinone reducing agent, such as hydrosulphite, dithionite, or diluted in malic, ascorbic acid or zinc glacial acetic acid. In the same way, you can also transfer individual endings of both rows into each other.

The invention also includes the previously known 3-hydroxyrifamycin, insofar as it is produced by the method according to the invention, and in particular the new 3-hydroxyrifamycin S-derivatives with the general formula Ia

in which R and R' each means a hydrogen atom or R' means acetyl and R means an optionally substituted hydrocarbyl, or acyl of a carboxylic acid, and the corresponding rifamycin SV derivatives with 1,4-hydroquinone structure as pharmaceutical compositions and preparations in dosage form, which contains

holds these '.-3-hydroxy-rifamycin-S-derivatives and process for their preparation. The subject of the invention is also the use of the new 3-hydroxyrifamycin-,S-derivatives and the corresponding pharmaceutical products, as antibiotics, especially antimicrobials, above all against cocci and bacteria-active

means, by as well as the medical methods for treating infections, especially bacterial infections in warm-blooded animals, above all in humans, but also in farm animals, by administering these compounds or their pharmaceutical forms.

The above characterized 3-hydroxyrifamycin-S derivatives according to the invention can, thanks to their antibiotic, especially antimicrobial properties, find use as valuable chemotherapeutics in this area. They can also be used as an additive for lining agents and for preserving foodstuffs, as well as as disinfectants. Furthermore, they can also serve as the intermediate for the production of other useful compounds, especially antibiotically active rifamyin derivatives.

With regard to the antimicrobial application,

is to highlight in particular the compound of formula (I), in which R' means acetyl and R means a residue Alk of lower aliphatic character, an aromatic residue Ar or an acyl residue of formula

2 2

R CO-, where R means hydrogen, Alk or Ar.

The aromatic residue denoted by the symbol Ar,

is an unsubstituted or substituted carbocyclicmonocyclic aryl or heterocyclyl, such as e.g. phenyl, 2- and 3-furyl,

2- and 3-thienyl, 2-, 3-4-pyridyl, 2- and 5-pyrimidyl, 2-imidazolyl or 5-tetrazolyl. These residues, primarily phenyl, can have one or more of the following substituents! Lower alkyl, such as ethyl and especially methyl, halogen atoms, such as fluorine, chlorine and bromine, nitro, hydroxy, lower alkoxy, such as ethoxy and especially methoxy, methylenedioxy, formyl, carboxyl, lower alkoxy-carbonyl, such as methoxy- and ethoxycarbonyl, amino, di-lower-alkylamino, such as diethyl- and dimethylamino-, and acylamino, such as lower-alkanoylamino, especially acetamino.

The residue of lower-aliphatic character denoted by the symbol Alk is an optionally substituted lower-alkyl or lower-alkenyl, or a corresponding cycloalkyl, resp. cycloalkenyl with a maximum of 7 carbon atoms. These residues may have one or more optionally substituted aromatic residues Ar and/or be substituted with one or more of the following

functional groups: Hydroxyl, lower-alkoxy, such as methoxy,

and ethoxy, aryloxy as phenoxy or optionally as mentioned above for the residue Ar, substituted phenoxy, lower-alkanoyloxy, as formyloxy and acetoxy, oxo, as aldehydo. and keto, as well as the corresponding acetals, resp. ketals, especially those with lower-alkanols such as lower-alkane (1,2- or 1,3)-diols, carboxyl, carbamoyl, lower-alkoxycarbonyl, such as methoxy and ethoxycarbonyl, nitro, as well as disubstituted amino, such as dimethylamino. Among the unsubstituted lower-alkyl and lower-alkenyl residues, as well as among the corresponding cycloaliphatic analogues, preference is particularly mentioned at the beginning, among the corresponding substituted residues, it is for example

mention the following: A hydroxyalkyl, e.g.; lower-alkoxy-lower-alkyl, e.g. methoxymethyl, 2-methoxyethyl, and 2-ethoxyethyl,

a carboxy-lower alkyl, such as carboxymethyl, 1- and 2-carboxy-ethyl, 3-carboxypropyl and 4-carboxybutyl, as well as corresponding residues, where the carboxyl group is present as an amide or an ester, especially a lower alkyl ester, f e.g. ethyl ester,

and especially methyl ester. As an example of a lower-alkyl or lower-alkenyl substituted by means of aromatic residues Ar, it is particularly worth mentioning: Benzyl, diphenylmethyl, furfuryl, thenyl, 2-phenylethyl, styryl and cinnamyl, which can also be substituted on the above manner.

2 2

In acyl R CO-, R can have all the aforementioned meanings for Alk and Ar, preferably R 2CO- is the residue of an optionally substituted lower-alkane, lower-alkene, aryl or heterocyclylcarboxylic acid or the formyl residue. Among preferred functional groups, which appear in such substituted carboxylic acids are to mention: Hydroxy, methoxy, halogen, especially chlorine, nitro, lower-alkoxycarbonyl, especially methoxycarbonyl, and di-lower-alkylamino-, especially dimethylamino, at<e> the aromatic also formyl, methylenedioxy and primary amino.

Among particularly preferred lower alkane or alkene carboxylic acids, it is worth mentioning in particular: Acetyl, propionyl, butyryl, chloroacetyl, trifluoroacetyl, nitroacetyl, glycoloyl, lactoyl, 4.-oxopentanoyl, methoxyacetyl, methokalyl, ethoxalyl, N,N-dimethylglycyl, glutaminyl, acryloyl, methacryloyl, crotonoyl, phenylacetyl, cinnamoyl, phenoxyacetyl, 2-furylacetyl, 2-furan-acryloyl, ^.-pyr in dinpropionyl. Among preferred "residues" of aryl and heterocyclylcarboxylic acid, it is particularly worth mentioning: Benzoyl, p-nitrobenzoyl, p-methoxybenzoyl, p-chlorobenzoyl,

o-, m- and p-toluoyl, 2, J+, 6-trimeylbenzoyl, salicyloyl, p-hydroxybenzoyl, furoyl, thenoyl, 2-pyridine carbophyll, nicotin-oyl, isonicotinoyl, as well as 1- and 5- tetrazolecarbonyl.

These new compounds are distinguished by their valuable pharmacological properties: Thus, according to the in vitro results, they have antibiotic, especially antibacterial properties^, such as e.g. on the one hand against gram-positive and gram-negative cocci, such as staphylococcus aureus, streptococcus, pyogenes, streptococcus, pneumonia, neisseria, meningitis, neisseria gonorrhoea (in investigated concentration ranges 0.01 to 8 mcg/ml), on the other hand against gram-negative rod bacteria, such as enterobacteriaceae, pseudomonas aeruginosa, haemophilus influenzae (in investigated concentration ranges of

0.01 to 64 mg/ml). Particularly to be highlighted as active substances are 3-acetoxy-, 3-benzoyl-, 3-phenoxy-, 3-(2-methoxyethyl)

and above all 3-methoxyrifamycin-S, all of which have a clear inhibitory effect already below the mentioned lowest concentration.

In connection with these favorable properties, the inventor's invention also covers the use of the new 3-hydroxyrifamycin-S derivatives, alone or in combination with other antibiotics or chemotherapeutics, as a means of combating infections caused by bacteria or cocci, e.g. .ex. those mentioned, namely both as a healing agent and also as a disinfectant. When used as a healing agent, the active substances according to the invention are preferably administered in the form of a pharmaceutical preparation together with at least one common pharmaceutical carrier or excipient to a warm-blooded animal, above all humans.

For the manufacture of pharmaceutical preparations,

can each of the compounds according to the invention, rather than

all one of the particularly highlighting, mixed with a too two-whip, . v-enteral or parenteral application of suitable inorganic or organic carrier material. For this, such substances that do not react with there; new compounds, such as e.g. gelatins, milk sugar, starch, magnesium stearate, vegetable oil, benzyl alcohol, or other drug carriers. The pharmaceutical preparations can e.g. available as tablets, dragees, powders, suppositories, or in liquid form, as solvents, suspensions, emulsions, creams or ointments. Possibly they are sterilized and/or

contains auxiliary substances such as preservatives, stabilisers, wetting agents or emulsifiers. They may also contain other therapeutically valuable substances. The disinfectants can also be mixed with suitable carriers as known.

The dosage of the active substances, e.g., the 3-hydroxyrifamycin-S derivatives highlighted above, takes place in principle, analogously to that of recognized antibiotics of the rifamycin type, however, it also depends on the one hand on the type of body weight, age; And the individual condition of the warm-blooded animal, on the other hand, of the method of application, and especially of the possible sensitivity of the pathogen which can be determined in a known manner in a routine test.

The invention also relates to a method for eradicating a growth impediment (i.e. inhibition) of a microorganism which is sensitive to at least one of the 3-hydroxyfamycin-S derivatives according to the invention, which is characterized by treatment of this microorganism, or a by this microorganism in- fissured medium with an antimicrobial effective dose of one of the 3-hydroxyfamycin-S derivatives according to the invention. The term "a microbial effective dose" is understood to mean such an amount of the active substance, which is sufficient for an effective inhibition of the relevant microorganism to be treated.

The invention shall be explained in more detail by means of non-limiting examples. The composition of the solvent-agent mixtures is given in volume ratios.

Example 1

A solution of 3.0 g of 3-bromo-rifamycin-S in 50

ml of methanol and 60 ml of phosphate buffer of pH 8.0 (0.065 mol Na^HPO^and 0.004. mol KHgPO^pr, liter of water) are heated for 4 hours under reflux. Thereby, the color of the reaction solution changes, from blue-violet to yellow-brown. The reaction solution is then oxidized with excess potassium ferricyanide, and extracted after acidification to pH 3 with chloroform. After drying and evaporating the chloroform extract, the residue is dissolved in ether and the ether solution is extracted exhaustively with phosphate buffer at pH = 6. The burgundy aqueous buffer extract is acidified until it turns yellow, and the separated 3-hydroxyrifamycin-S is treated with chloroform. After the evaporation of the chloroform, 3-hydroxyrifamycin-S appears in the form of a yellow foam, the identity of which with the previously formed fermentation product, allows you to confirm by means of thin-layer chromatography 360-MHz-<1>H-NMR spectra, as well as by UV - and IR spectra.

Example 2

A mixture of 1.0 g of 3-bromrifamycin-S, 0.5 g of anhydrous sodium acetate and 30 ml of methanol is heated in a pressure tube for 5 hours at 75°C. The reaction mixture is evaporated, acidified with citric acid, and chromatographed on silica gel with chloroform-acetone (19:1) as eluent. First eluted material consists of pure 3-methoxyrifamycin-S, 100 MHz 1H-NMR spectrum (in CDCl^): no signal for H-3»4-. 16 ppm (s, 3H, OCH^ of 0-3), UV spectrum (EtOH, nm/f ni 3.x) :<2>15/26900, 268/234-00,~300 (shoulder), ~ 350 (shoulder), 396/4-360, IR spectrum (CH2Cl2): 3500 (OH), 34-00 (NHCO), 1735 (Ester, 5-ring ketone), 1670"(Amide-I, quinone-C0) , 16£0 (quinone-CO bridged) cm"<1>, mass spectrum: m/e = 725 (C^gH NO^), strong fragments: 709, 693, 695, 635, 303, 4-23, etc.

Example 3

A solution of 1.0 g of 3-bromrifamycin-S in 30 ml of 2-methoxyethanol, containing suspended 0.5 g of anhydrous sodium acetate, is heated for 1 hour at 90° C. with stirring, and evaporated. The residue is treated with citric acid and chromatographed on silica gel with methylene chloride-acetone (19:1) as eluent. It formed 3-(2-methoxyethoxy)-rifamycin-S

is characterized as follows: 100 MHz 1H-NMR spectrum (in CDCl^): signals of the C-3 substituents at 3.36 (s,3H,0CH^), ~3.7 (m) and 4.62 (m , 0CH2CH20CH3) ppm.

Example 4

A solution of 1.5 g of 3-bromrifamycin-S and 0.75 g of phenol in 30 ml of dimethylsulfoxide is mixed with 0.75 g of anhydrous sodium acetate and heated for 3 hours at 90°C. After cooling, the reaction mixture is mixed with excess aqueous potassium ferricyanide solution and acidified with citric acid,

the reaction products formed are taken up in chloroform. The material contained in the chloroform extract, when chromatographed with silica gel with chloroform-acetone (19:1) gives firstly 3-bromorifamaiciri-S, then the desired -3-phenoxyrifamycin-S, 100-MHz- -iH-NMR spectrum ( in CDCl^): signals of the phenoxy substituents at 6.8-7.4- (m, 5S)ppm, UV spectrum (0.01-N-alcoholic hydrochloric acid, nm/£ ): 220/34-600, 266 (shoulder), 270/24-800, 34-2/6000, 400 (shoulder).

Example 5

A mixture of 2.0 g of 3-bromorifamycin-S with 2 g of anhydrous sodium acetate and 50 ml of dimethylsulfoxide is heated for 1 hour at 90°C. Thereby, the initially bluish-violet color of the reaction mixture changes to brown-red, „Then, an excess of aqueous potassium ferricyanide solution is added, acidified with citric acid, and the reaction products formed are taken up with ether. The ether solution is extracted with 3-acetoxyrifamycin-S by repeatedly equipping with phosphate buffer of pH

6.0. The combined aqueous buffer extracts are acidified with citric acid, and the precipitated 3-acetoxyrifamycin-S is taken up with chloroform. After drying and evaporating the chloroform extract, practically pure 3-acetoxyrifamycin-S is obtained, which crystallizes from ethers in pale yellow needles, m.p. 154-155°C Mass spectrum: m/e = 753 (C^^H^yNO^), characteristic

fragments at: 723, 721, 713, 711, 705, 695, 693, 663, 661. 100 MHz <1>H-NMR spectrum (in CDCl^): Signals of 2-acetyl groups at 2.10 (s, 6H) ppm, UV spectrum (0.01-N alcoholic hydrochloric acid

nm/f ): 226/33100, 273/26700, 34-0/6200, 390/4260.

ffl clX

Example 6

A mixture of 2.0 g of 3-bromorifamycin-S with 2 g of anhydrous sodium benzoate and 30 ml of dimethylformamide is heated for 2 1/2 hours at 70°C. The reaction mixture then changes, starting with a blue-violet color, to brown-red. An excess of aqueous potassium ferricyanide solution is then added, acidified with citric acid, and the reaction products formed are taken up with ether. From the ether solution, 3-benzoyloxyrifamycin-S is extracted by repeated addition of phosphate buffer of pH = 6.0. The combined aqueous buffer extracts are acidified with citric acid, and the separated 3-benzoyloxyrifamycin-S is taken up with chloroform. After drying and evaporating the chloroform extract, 3-benzoyloxyrifamycin-S is obtained, mass spectrum: After silylation m/c 1031 (Tris-trimethylsilyl derivative of 3-benzoyloxyrifamycin-S). 100 MHz 1 H NMR spectrum (in CDCl 2 ): signals of benzoyl groups at 7.3-8.1 (m, 5 H)ppm.

Example 7

A mixture of 2.0 g of 3-bromrifamycin-S, 1.0 g of sodium acetate, 1.0 g of p-hydroxybenzaldehyde and 30 ml of acetonitrile is heated in a pressure tube for 2 hours at 100°C, and evaporated. The residue is taken up in ethyl acetate, washed with aqueous citric acid solution, dried and evaporated. Chromatography on silica gel with methylene chloride-acetone (98:2) as eluent first gives traces of fast migrating material, and then as the main fraction 3-(4-formylphenoxy)-rifamycin-S, which after evaporation appears as a yellow foam. 100 MHz H-NMR spectrum (CDCl^): Signals of aromatic H in AB spectrum centered at 7.07 and

7.8 (J<*>9 Hz, 4.H), aldehyde signal at 12.7 (S,1H)ppm. IR spectrum (CH 2 Cl 2 ): 34-75 (OH), 3380 (NH), 2730 (OH), 1740 (5-ring-CO), 1705 (Ester, CHO), 1675 (amide i), 1645 (quinone) , 1620 (quinone), 1600 (C=C ring opening) cm" _ -i etc, UV spectrum

(0.0-N alcoholic hydrochloric acids, nm/6 ) 214/38000, 269/34000, 345/6400, 400 (shoulder).

Example 8

By the same working method as described in example 1, however using sodium carbonate instead of phosphate buffer, 25-O-desacetyl-3-hydroxyrifamycin-S is obtained in the described manner as a yellow powder. 100 MHz 1 H NMR spectrum (CDCl 2 ) is analogous to 3-h-dyroxyrifamycin-S, however, at 2.1 ppm the added signal of the CH 2 CO 2 O group is missing.

Claims (13)

1. Method for introducing a free, etherified or esterified hydroxyl group in the 3-position of rifamycin-S, characterized in that in 3-bromorifamycin-S bromine is exchanged for a free, etherified or esterified hydroxyl group. 2. Method according to claim 1, kara k\. characterized in that for the preparation of a compound of formula in which R and R' each means a hydrogen atom or R' means acetyl, and R means hydrogen, a possibly substituted hydrcarbyl or the acyl residue of a carboxylic acid, or the corresponding derivative of the SV series, 3-bromorifamycin-S is treated with the formula with a compound of formula ROH (III), in which R has the above-mentioned meaning, or a salt thereof, in a neutral to basic environment, and optionally in the presence of a bromine-hydrogen binding agent, and/or an organic solvent, and the product is isolated in the form of a derivative of the S series or the Sv series. 3. Method according to claim 1 or 2, kc.a r..a k-terized in that for the production of compounds of formula (I), in which R means hydrogen, the starting material of formula (II) is heated in a aqueous environment in the presence of an alcohol or a water-miscible polar aprotic organic solvent at pH between 7.0 to 10.0. 4-. Method according to claim 3" characterized in that by reaction in pH ranges around 9.0, 25-O-desacetyl-3-hydroxyrifamycin-S is prepared, with formula (I), in which each R and R' means hydrogen. 5. Process according to claim 3" characterized in that by reaction in the pH range between 7.0 and 8.0, 3-hydroxyrifamycin-S is prepared with formula (I), in which R means hydrogen and R' acetyl. 6. Process according to claim 1 or 2, characterized by attman for the preparation of a compound of formula (I), in which R means hydrocarbyl, reacts the starting material of formula (II) with a molar excess of the corresponding alcohol to formula ROH in the presence of a maximum of 2 molar equivalents of an alkali metal salt of a carboxylic acid, preferably sodium acetate. 7. Process according to claim 1 or 2, characterized in that for the preparation of a compound of formula (I), in which R' means an acyl residue, R 1 CO- in which R <1> means a hydrogen or hydrocarbyl, the starting material is reacted with formula (II) with an alkali metal salt of a corresponding carboxylic acid R 1CO0H in an anhydrous aprotic polar solvent. 8. Method according to one of claims 1-7, carried out essentially in the manner described in examples 1-8. 9. Method according to one of the claims 1-4 and 6-8, characterized in that by a suitable choice of starting material of formula ROH and reaction conditions, a rifamycin S-derivative of formula CH3 in which R and R' each means a hydrogen atom or R' means acetyl, and R optionally substituted hydrocarbyl or acyl.ej.: the remainder of a carboxylic acid, or a corresponding derivative of the SV series. 10. The method according to one of claims 1-4. and 6-8, character shown by a suitable choice of starting material having the formula ROH and 1 reaction ion conditions being produced with a compound of formula Ia, where R' means acetyl, and R means a residue Alk lower-aliphatic character , an aromatic residue Ar, or an acyl residue R 2 CO — , in which R 2 means hydrogen, Alk or Ar, and a corresponding derivative of the SV series. 11. Method according to one of claims 1-4. and 8, characterized in that with a - y.& lg of the starting material with formula ROH and the reaction conditions, a compound is prepared from the group consisting of 3-phenoxyrifamycin-S, 3-acetoxyrifamycin-S, 3-benzoylrifamycin-S, 3-(4--formylphenoxy)-rifamycin-S and 25-0-desacetyl-3-hydroxyrifamycin-S. 12. Process according to one of claims 1, 2, 6 and 8, characterized in that, by a suitable choice of starting material, a compound of formula R0H.l.in the reaction condition is prepared by 3-methoxyrifamycin-S. 13. The method according to one of claims 1, 2, 6 and 8, characterized in that 3-(methoxyethoxy)-rifamycin-S is produced by a suitable choice of the starting material with formula ROH and the reaction conditions.