# Patent

## Title
Processes for preparing of glucopyranosyl-substituted benzyl-benzene derivatives and intermediates therein

## Abstract

The present invention relates to processes for preparing the compounds of general formula I,




wherein the groups R1 and R3 are defined according to claim 1. Furthermore this inventions relates to intermediates obtained in these processes.

## Background
This application claims priority to EP 05010115, filed May 10, 2005; EP05018265, filed Aug. 23, 2005; and EP 05108484, filed Sep. 15, 2005.
The present invention relates to a process for preparing of glucopyranosyl-substituted benzyl-benzene derivatives of the formula I,




wherein the substituents R1 and R3 are defined as hereinafter. Furthermore the present invention relates to processes for preparing intermediates and starting materials of the process for preparing of glucopyranosyl-substituted benzyl-benzene derivatives. In addition the present invention relates to such intermediates and starting material.

BACKGROUND OF THE INVENTION
In the international patent application WO 2005/092877 glucopyranosyl-substituted benzene derivatives of the general formula




wherein the groups R1 to R6 and R7a, R7b, R7c are as defined therein, are described. Such compounds have a valuable inhibitory effect on the sodium-dependent glucose cotransporter SGLT, particularly SGLT2.

AIM OF THE INVENTION
The aim of the present invention is to find new processes for preparing of glucopyranosyl-substituted benzyl-benzene derivatives of the formula I; in particular processes with which the product may be obtained in high yields, high enantiomeric or diastereomeric purity and which allow the manufacture of the product in a commercial scale with a low technical expenditure and a high space/time yield.
Another aim of the present invention is to provide processes for preparing the starting materials of the beforementioned method of manufacture.
Further aims of the present invention relate to new intermediates and starting materials in the process according to the present invention.
Other aims of the present invention will become apparent to the skilled artisan directly from the foregoing and following description.
OBJECT OF THE INVENTION
In a first aspect the present invention relates to a process for preparing the compounds of general formula I,




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

R3 denotes hydrogen;

characterised in that in a compound of general formula II





wherein R1 is defined as hereinbefore and

R2 independently of one another denote hydrogen, (C1-18-alkyl)carbonyl, (C1-18-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl, aryl-C1-3-alkyl, allyl, RaRbRcSi, CRaRbORc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SIRaRb, CRaRb or CRaORb—CRaORb; with the proviso that at least one substituent R2 is not hydrogen;

Ra, Rb, Rc independently of one another denote C1-4-alkyl, aryl or aryl-C1-3-alkyl, while the alkyl may be mono- or polysubstituted by halogen;

L1 independently of one another are selected from among fluorine, chlorine, bromine, C1-3-alkyl, C1-4-alkoxy and nitro;

while by the aryl groups mentioned in the definition of the above groups are meant phenyl or naphthyl groups, preferably phenyl groups, which may be mono- or polysubstituted with L1;

the protective groups R2 not being hydrogen are cleaved, in particular hydrolysed.

In a second aspect the present invention relates to a process for preparing the compounds of general formula II,




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

R2 independently of one another denote hydrogen, (C1-18-alkyl)carbonyl, (C1-18-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl, aryl-C1-3-alkyl, allyl, RaRbRcSi, CRaRbORc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SiRaRb, CRaRb or CRaORb—CRaORb;

Ra, Rb, Rc independently of one another denote C1-4-alkyl, aryl or aryl-C1-3-alkyl, while the alkyl groups may be mono- or polysubstituted by halogen;

L1 independently of one another are selected from among fluorine, chlorine, bromine, C1-3-alkyl, C1-4-alkoxy and nitro;

while by the aryl groups mentioned in the definition of the above groups are meant phenyl or naphthyl groups, preferably phenyl groups, which may be mono- or polysubstituted with L1;

characterised in that a compound of general formula III





wherein R1 and each R2 are defined as hereinbefore and

R′ denotes hydrogen, C1-6-alkyl, (C1-4-alkyl)carbonyl, (C1-4-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl;

while the term “aryl” is defined as hereinbefore;

is reacted with a reducing agent.

In a third aspect the present invention relates to a process for preparing the compounds of general formula III,




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

R2 independently of one another denote hydrogen, (C1-18-alkyl)carbonyl, (C1-18-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl, aryl-C1-3-alkyl, allyl, RaRbRcSi, CRaRbORc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SiRaRb, CRaRb or CRaORb—CRaORb; and

Ra, Rb, Rc independently of one another denote C1-4-alkyl, aryl or aryl-C1-3-alkyl, while the alkyl groups may be mono- or polysubstituted by halogen;

L1 independently of one another are selected from among fluorine, chlorine, bromine, C1-3-alkyl, C1-4-alkoxy and nitro;

R′ denotes hydrogen, C1-6-alkyl, (C1-4-alkyl)carbonyl, (C1-4-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl;

while by the aryl groups mentioned in the definition of the above groups are meant phenyl or naphthyl groups, preferably phenyl groups, which may be mono- or polysubstituted with L1;

characterised in that an organometallic compound of the formula VI





wherein R1 is defined as hereinbefore and M denotes Li or MgHal, wherein Hal denotes Cl, Br or I;

or a derivative thereof obtained by transmetallation;

which compound of the formula VI may be obtained by halogen-metal exchange or by the insertion of a metal in the carbon-halogen bond of a halogen-benzylbenzene compound of general formula V





wherein R1 is defined as hereinbefore and X denotes Br or I;

and optionally subsequent transmetallation, is added to a gluconolactone of general formula IV





wherein R2 is as hereinbefore defined,

then the adduct obtained is reacted with water or an alcohol R′—OH, where R′ denotes C1-6-alkyl, in the presence of an acid and optionally the product obtained in the reaction with water wherein R′ denotes H is converted in a subsequent reaction with an acylating agent into the product of formula III wherein R′ denotes (C1-4-alkyl)carbonyl, (C1-4-alkyl)oxycarbonyl, arylcarbonyl or aryl-(C1-3-alkyl)-carbonyl, wherein the term “aryl” is defined as hereinbefore.

In a fourth aspect the present invention relates to a process for preparing the compounds of general formula XXXIII,




wherein R1, R2 are defined as hereinbefore and hereinafter;

characterised in that a protected D-glucal of the formula XXX





wherein R2 is defined as hereinbefore;

is metallated to yield a metallated D-glucal of the formula XXXI





wherein R2 is defined as hereinbefore and M denotes lithium or a magnesium moiety;

which is optionally transmetallated to yield a metallated D-glucal of the formula XXXI, wherein M denotes a magnesium, zinc, indium, boron, tin, silicon or chromium moiety; and

the metallated or trans-metallated D-glucal of the formula XXXI is reacted with an aglycon of the formula V





wherein R1 is defined as hereinbefore and X denotes a leaving group;

in the presence of a transition metal catalyst

to yield a glucal derivative of the formula XXXII





wherein R1 and R2 are defined as hereinbefore; and

the glucal derivative of the formula XXXII is converted to the product of the formula XXXIII by the addition of water to the double bond of the glucal moiety, in particular by hydroboration of the double bond and subsequent cleavage of the carbon-boron bond or by epoxidation or dihydroxylation of the double bond and subsequent reduction of the resultant anomeric carbon-oxygen bond.

In a fifth aspect the present invention relates to a process for preparing the compounds of general formula XXXIII,




wherein R1, R2 are defined as hereinbefore and hereinafter;

characterised in that a protected D-glucal of the formula XXX





wherein R2 is defined as hereinbefore;

is epoxidated to yield the corresponding glucaloxide of the formula XXXIV





wherein R2 is defined as hereinbefore; and

the glucaloxide of the formula XXXIV is reacted with a metallated aglycon of the formula VI





wherein R1 is defined as hereinbefore and M denotes a lithium, magnesium, zinc, indium, aluminum or boron moiety;

to yield the product of the formula XXXIII.

In a sixth aspect the present invention relates to a process for preparing the compounds of general formula II,




wherein R1, R2 are defined as hereinbefore and hereinafter;

characterised in that a glucose derivative of the formula XXXV





wherein R2 is defined as hereinbefore and

Hal denotes F, Cl, Br, C1-3-alkylcarbonyloxy, C1-3-alkyloxycarbonyloxy or C1-3-alkyloxy;

is reacted with a metallated aglycon of the formula VI





wherein R1 is defined as hereinbefore and M denotes a lithium, magnesium, zinc, indium or boron moiety;

to yield the product of the formula II.

In a seventh aspect the present invention relates to a process for preparing the compounds of general formula V,




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

X denotes a bromine atom or an iodine atom;

characterised in that a benzoyl chloride derivative of the formula XII





wherein X is defined as above; or a derivative thereof such as a benzoyl anhydride, an ester or a benzonitrile;

is reacted with a halobenzene of the formula XXVII





wherein Z5 denotes a fluorine, chlorine or iodine atom;

in the presence of a catalyst to obtain an intermediate compound of the formula XXVI





wherein X and Z5 are defined as hereinbefore; and

the intermediate compound of the formula XXVI is reacted with R1—OH, wherein R1 is defined as hereinbefore, or an anion thereof, preferably in a solvent or mixture of solvents, in the presence of a base to yield a benzophenone derivative of the formula VII





wherein X and R1 are defined as hereinbefore; and

the benzophenone derivative of the formula VII is reacted with a reducing agent, preferably in a solvent or mixture of solvents, in the presence of a Lewis acid to furnish the compound of the formula V as defined above.

In an eighth aspect the present invention relates to a process for preparing the compounds of general formula II,




wherein R1 and R2 are defined as hereinbefore,

characterized in that an aglycon of the formula V





wherein X and R1 are defined as hereinbefore, is obtained by a process according to the seventh aspect of this invention, and

said halogen-benzylbenzene compound of general formula V is transformed into an organometallic compound of the formula VI





wherein R1 is defined as hereinbefore and M denotes Li or MgHal, wherein Hal denotes Cl, Br or I;

by an halogen-metal exchange or by the insertion of a metal in the carbon-halogen bond of the halogen-benzylbenzene compound of general formula V, and optionally subsequent transmetallation; and

said organometallic compound of the formula VI is reacted with a gluconolactone of general formula IV





wherein R2 is as hereinbefore defined, in accordance with the process of the third aspect of this invention to obtain an intermediate of the formula III,





wherein R2, R′ and R1 are defined as hereinbefore, and

said intermediate of the formula III is reacted with a reducing agent in accordance with the second aspect of this invention to obtain the compound of the formula II.

In a ninth aspect the present invention relates to compounds of general formula II




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

R2 independently of one another denote hydrogen, (C1-18-alkyl)carbonyl, (C1-8-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl, aryl-C1-3-alkyl, allyl, RaRbRcSi, CRaRbORc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SiRaRb, CRaRb or CRaORb—CRaORb; with the proviso that at least one substituent R2 does not denote hydrogen;

Ra, Rb, Rc independently of one another denote C1-4-alkyl, aryl or aryl-C1-3-alkyl, while the alkyl groups may be mono- or polysubstituted by halogen;

L1 independently of one another are selected from among fluorine, chlorine, bromine, C1-3-alkyl, C1-4-alkoxy and nitro;

while by the aryl groups mentioned in the definition of the above groups are meant phenyl or naphthyl groups, preferably phenyl groups, which may be mono- or polysubstituted with L1.

In a further aspect the present invention relates to compounds of general formula III




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

R2 independently of one another denote hydrogen, (C1-18-alkyl)carbonyl, (C1-18-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl, aryl-C1-3-alkyl, allyl, RaRbRcSi, CRaRbORc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SiRaRb, CRaRb or CRaORb—CRaORb;

Ra, Rb, Rc independently of one another denote C1-4-alkyl, aryl or aryl-C1-3-alkyl, while the alkyl or aryl groups may be mono- or polysubstituted by halogen;

L1 independently of one another are selected from among fluorine, chlorine, bromine, C1-3-alkyl, C1-4-alkoxy and nitro;

R′ denotes hydrogen, C1-6-alkyl, (C1-4-alkyl)carbonyl, (C1-4-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl;

while by the aryl groups mentioned in the definition of the above groups are meant phenyl or naphthyl groups, preferably phenyl groups, which may be mono- or polysubstituted with L1.

In a further aspect the present invention relates to compounds of general formula VI




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

M denotes Li or MgHal, wherein Hal denotes Cl, Br or I.

In a further aspect the present invention relates to compounds of general formula V




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

X denotes Br or I.

In a further aspect the present invention relates to compounds of the formula VII




or of the formula XIX





wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

X denotes Br or I.

In a further aspect the present invention relates to compounds of the formula XXVI




wherein

X denotes Br or I; and

Z denotes hydroxy, fluorine, chlorine, bromine, iodine, C1-4-alkyl-sulfonyloxy, arylsulfonyloxy, aryl-C1-3-alkyl-sulfonyloxy, di-(C1-6-alkyloxy)-boronyl, di-hydroxy-boronyl, KF3B, NaF3B or LiF3B; and

the term “aryl” is defined as hereinbefore.

In a further aspect the present invention relates to compounds of the formula XXXII




wherein

R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and

R2 independently of one another denote hydrogen, (C1-18-alkyl)carbonyl, (C1-18-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl, aryl-C1-3-alkyl, allyl, RaRbRcSi, CRaRbORc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SiRaRb, CRaRb or CRaORb—CRaORb;

Ra, Rb, Rc independently of one another denote C1-4-alkyl, aryl or aryl-C1-3-alkyl, while the alkyl groups may be mono- or polysubstituted by halogen;

L1 independently of one another are selected from among fluorine, chlorine, bromine, C1-3-alkyl, C1-4-alkoxy and nitro;

while by the aryl groups mentioned in the definition of the above groups are meant phenyl or naphthyl groups, preferably phenyl groups, which may be mono- or polysubstituted with L1.



DETAILED DESCRIPTION OF THE INVENTION
Unless otherwise stated, the groups, residues and substituents, particularly R1, R2, R3, R′, R1, Rb, Rc, L1, M, X and Z, are defined as above and hereinafter.
If residues, substituents or groups occur several times in a compound, they may have the same or different meanings.
In the processes and compounds according to this invention the following meanings of groups and substituents are preferred:
R1 preferably denotes R-tetrahydrofuran-3-yl or S-tetrahydrofuran-3-yl.
R2 preferably denotes hydrogen, methylcarbonyl, ethylcarbonyl or trimethylsilyl.
Ra, Rb, Rc independently of one another preferably denote methyl, ethyl, n-propyl or i-propyl, tert.-butyl or phenyl; most preferably methyl.
R′ preferably denotes hydrogen, methyl or ethyl.
In the following the processes according to this invention are described in detail.
The Scheme 0 depicts the conversion of compound II to compound I via removal of the protective groups R2 not being hydrogen present in compound II, wherein R1, R2 and R3 are defined as hereinbefore.




Any acyl protecting group R2 used is cleaved for example hydrolytically in an aqueous solvent, e.g. in water, isopropanol/water, acetic acid/water, tetrahydrofuran/water or dioxane/water, in the presence of an acid such as trifluoroacetic acid, hydrochloric acid or sulphuric acid or in the presence of an alkali metal base such as lithium hydroxide, sodium hydroxide or potassium hydroxide or aprotically, e.g. in the presence of iodotrimethylsilane, at temperatures between 0 and 120° C., preferably at temperatures between 10 and 100° C.
A trifluoroacetyl group R2 is preferably cleaved by treating with an acid such as hydrochloric acid, optionally in the presence of a solvent such as acetic acid at temperatures between 50 and 120° C. or by treating with sodium hydroxide solution optionally in the presence of a solvent such as tetrahydrofuran or methanol at temperatures between 0 and 50° C.
Any acetal or ketal protecting group R2 used is cleaved for example hydrolytically in an aqueous solvent or aqueous mixture of solvents, e.g. in water, isopropanol/water, acetic acid/water, tetrahydrofuran/water or dioxane/water, in the presence of an acid such as trifluoroacetic acid, hydrochloric acid or sulphuric acid or aprotically, e.g. in the presence of iodotrimethylsilane, at temperatures between 0 and 120° C., preferably at temperatures between 10 and 100° C.
A silyl group R2, for example trimethylsilyl, is cleaved for example in water, an aqueous solvent mixture or a lower alcohol such as methanol or ethanol in the presence of a base such as lithium hydroxide, sodium hydroxide, potassium carbonate or sodium methoxide.
In aqueous or alcoholic solvents, acids such as e.g. hydrochloric acid, trifluoroacetic acid or acetic acid are also suitable. For cleaving in organic solvents, such as for example diethyl ether, tetrahydrofuran or dichloromethane, it is also suitable to use fluoride reagents, such as e.g. tetrabutylammonium fluoride.
A benzyl, methoxybenzyl or benzyloxycarbonyl group R2 is advantageously cleaved hydrogenolytically, e.g. with hydrogen in the presence of a catalyst such as palladium/charcoal in a suitable solvent such as methanol, ethanol, ethyl acetate or glacial acetic acid, optionally with the addition of an acid such as hydrochloric acid at temperatures between 0 and 100° C., but preferably at ambient temperatures between 20 and 60° C., and at a hydrogen pressure of 1 to 7 bar, but preferably 3 to 5 bar. A 2,4-dimethoxybenzyl group, however, is preferably cleaved in trifluoroacetic acid in the presence of anisole.
A tert.butyl or tert.butyloxycarbonyl group R2 is preferably cleaved by treating with an acid such as trifluoroacetic acid or hydrochloric acid or by treating with iodotrimethylsilane optionally using a solvent such as methylene chloride, dioxane, methanol or diethylether.
The glucose derivatives of formula II may be synthesized via reduction of the anomeric carbon-oxygen bond of compound III (Scheme 1).




R′ and R1 are defined as hereinbefore. R2 is defined as hereinbefore and represents for example hydrogen, acetyl, pivaloyl, benzoyl, tert-butoxycarbonyl, benzyloxycarbonyl, trialkylsilyl, benzyl or substituted benzyl. In case two adjacent groups R2 are linked with each other to form a bridging group they preferably form an acetal such as e.g. benzylideneacetal, a ketal such as e.g. isopropylideneketal, or an ethylene group that results in the formation of a dioxane such as e.g. the combination with 2,3-dimethoxy-butylene which is linked via position 2 and 3 of the butylene group to the oxygen atoms of the pyranose. A preferred meaning of R2 is hydrogen or tri-(C1-3-alkyl)silyl, such as trimethylsilyl or triisopropylsilyl. R′ preferably denotes hydrogen or C1-4-alkyl, in particular methyl or ethyl.
The reduction may be conducted with a reducing agent in the presence of or without a Lewis acid. Suitable reducing agents include for example silanes such as e.g. triethylsilane, tripropylsilane, triisopropylsilane, or diphenylsilane, sodium borohydride, sodium cyanoborohydride, zinc borohydride, borane complexes, lithium aluminum hydride, diisobutylaluminum hydride, or samarium iodide. Suitable Lewis acids are such as e.g. boron trifluoride etherate, trimethylsilyl triflate, titanium tetrachloride, tin tetrachloride, scandium triflate, copper(II) triflate, or zinc iodide; or suitable Lewis acids are Brønsted acids such as e.g. hydrochloric acid, toluenesulfonic acid, trifluoroacetic acid, or acetic acid. Depending on the reducing agent the reductions may be carried out without a Lewis acid. The reaction may be carried out in a solvent such as for example methylene chloride, chloroform, acetonitrile, toluene, hexane, diethylether, tetrahydrofuran, dioxane, ethanol, water, or mixtures thereof. The solvent is preferably selected in view of the reducing agent and the optional Lewis acid. Preferred reaction temperatures are between −80° C. and 120° C., more preferably between −30 and 80° C.
One particularly suitable combination of reagents consists for example of triethylsilane and boron trifluoride etherate, which is conveniently used in acetonitrile, dichloromethane, or mixtures thereof at temperatures from −60° C. to 60° C.
The reduction is preferably carried out in the absence of water, in particular with a content of water in the reaction mixture below 2000 ppm, even more preferably below 1000 ppm.
In addition to the reducing agents mentioned above, hydrogen may be used for the reduction intended. This transformation may be accomplished in the presence of a transition metal catalyst such as e.g. palladium on charcoal, palladium oxide, platinum oxide, or Raney nickel, in solvents such as e.g. tetrahydrofuran, ethyl acetate, methanol, ethanol, water, or acetic acid at temperatures of −40° C. to 100° C. and at hydrogen pressures of 1 to 10 Torr.
The glucose derivatives of formula III may be synthesized from D-gluconolactone or a derivative thereof by reacting the desired benzylbenzene compound in the form of an organometallic compound (Scheme 2a).




The Scheme 2a and the following sections describe preferred conditions and embodiments of the process according to the third aspect of this invention.
The Grignard or Lithium reagent of benzylbenzene (VI) may be prepared from the corresponding brominated or iodinated benzylbenzene V either via a so-called halogen-metal exchange reaction or by inserting the metal into the carbon-halogen bond. The halogen-metal exchange to synthesize the corresponding lithium compound VI may be carried out for example with an organolithium compound such as e.g. n-, sec- or tert-butyllithium. A preferred amount of the organolithium compound is in the range from about 1 to 2 mol, more preferably about equimolar with respect to the benzylbenzene V.
The analogous magnesium compound may also be generated by a halogen-metal exchange with a suitable Grignard reagent such as C3-4-alkylmagnesium chloride or bromide, for example isopropyl- or sec-butylmagnesium bromide or chloride or diisopropyl- or di-sec-butylmagnesium without or in the presence of an additional salt such as e.g. lithium chloride that may accelerate the metalation process. The specific transmetalating organomagnesium compound may also be generated in situ from suitable precursors (see e.g. Angew. Chem. 2004, 116, 3396-3399 and Angew. Chem. 2006, 118, 165-169 and references quoted therein). The Grignard reagent is preferably used in an amount in the range from about 1 to 5 mol per mol of the benzylbenzene V.
The halogen-metal exchange reactions are preferably carried out between −100° C. and 40° C., particularly preferably between −80° C. and 10° C. A more preferred temperature range in the halogen-lithium exchange reaction is −80° C. and −15° C.
Preferably the halogen-metal exchange reaction is carried out in an inert solvent or mixtures thereof, such as for example diethylether, dioxane, tetrahydrofuran, diethylene glycol dimethyl ether, toluene, hexane, dimethylsulfoxide, dichloromethane or mixtures thereof. Particularly preferred solvents are selected form among tetrahydrofuran, diethylene glycol dimethyl ether, hexane and mixtures thereof.
The magnesium or lithium derivatized compounds thus obtained may optionally be transmetalated with metal salts such as e.g. cerium trichloride, zinc chloride or bromide, indium chloride or bromide, to form alternative organometal compounds (VI) suitable for addition.
Alternatively, the organometal compound VI may also be prepared by inserting a metal into the carbon-halogen bond of the haloaromatic compound V. Lithium or magnesium are suitable elemental metals for this transformation. The insertion can be achieved in solvents such as e.g. diethylether, dioxane, tetrahydrofuran, toluene, hexane, dimethylsulfoxide and mixtures thereof at temperatures ranging from −80 to 100° C., preferably at −70 to 40° C. In cases in which no spontaneous reaction takes place prior activation of the metal might be necessary such as e.g. the treatment with 1,2-dibromoethane, iodine, trimethylsilylchloride, acetic acid, hydrochloric acid and/or sonication.
The addition of the organometal compound VI to gluconolactone or derivatives thereof (IV) is preferably carried out at temperatures between −100° C. and 40° C., particularly preferably at −80 to −10° C., in an inert solvent or mixtures thereof, to obtain the compound of formula III. In case the compound VI is a lithiumorganic compound the addition is even more preferably carried out at temperatures in the range from −80 to −20° C. In case the compound VI is a magnesiumorganic compound particularly preferred temperatures during the addition are in the range from −30° C. to −15° C.
All foregoing reactions may be performed in air though the execution under inert gas atmosphere is preferred. Argon and nitrogen are preferred inert gases.
The metalation and/or coupling reaction may also be carried out in microreactors and/or micromixers which enable high exchange rates; for example analogously to the processes described in WO 2004/076470.
Suitable solvents for the addition of the metalated compound VI to the appropriately protected gluconolactone IV are e.g. diethylether, toluene, methylene chloride, hexane, tetrahydrofuran, dioxane, N-methylpyrrolidone and mixtures thereof.
The addition reactions may be carried out without any further adjuvants or in the presence of a promoter such as e.g. BF3*OEt2 or Me3SiCl which may be advantageous in the case of sluggishly reacting coupling partners (see M. Schlosser, Organometallics in Synthesis, John Wiley & Sons, Chichester/New York/Brisbane/Toronto/Singapore, 1994).
Preferred definitions of the substituents R2 in Scheme 2a are benzyl, substituted benzyl, trialkylsilyl, particularly preferably tri-(C1-3-alkyl)silyl, such as trimethylsilyl, triisopropylsilyl, 4-methoxybenzyl and benzyl. If two adjacent substituents R2 are linked together, these two substituents are preferably part of a benzylideneacetal, 4-methoxybenzylideneacetal, isopropylketal or constitute a dioxane with 2,3-dimethoxy-butylene which is linked via the 2 and 3 positions of the butane with the adjacent oxygen atoms of the pyranose. The group R′ preferably denotes hydrogen, C1-4-alkyl, C1-4-alkylcarbonyl or C1-4-alkyloxycarbonyl, particularly preferably hydrogen, methyl or ethyl.
The group R′ is introduced after the addition of the organometallic compound VI or a derivative thereof to the gluconolactone IV. If R′ equals hydrogen or C1-4-alkyl the reaction solution is treated with an alcohol, in particular an C1-4-alkanol, such as e.g. methanol or ethanol or water in the presence of an acid such as e.g. acetic acid, methanesulfonic acid, toluenesulfonic acid, sulfuric acid, trifluoroacetic acid, or hydrochloric acid. This reaction with the alcohol or water is preferably carried out at temperatures in the range from about 0° C. to 80° C., particularly from about 20° C. to 60° C. During installing R′ the protective groups R2 may be cleaved if labile under the reaction conditions employed resulting in the corresponding protonated compound, i.e. compound III in which R2 equals H. For example protecting groups wherein R2 denotes trialkylsilyl, such as trimethylsilyl, are usually cleaved when the reaction solution is treated with an alcohol and/or water in the presence of an acid so that a compound III is obtained wherein R2 denotes H.
R′ may also be attached after preparation of the hydrogen compound III (R′═H) by reacting the anomeric hydroxyl group with a suitable electrophile such as e.g. methyl iodide, dimethyl sulfate, ethyl iodide, diethyl sulfate, acetyl chloride, or acetic anhydride in the presence of a base such as e.g. triethlyamine, ethyldiisopropylamine, sodium or potassium or cesium carbonate, sodium or potassium or cesium hydroxide. The hydroxyl group can also be deprotonated prior to the addition of the electrophile with e.g. sodium hydride.




Approach 2 depicted in Scheme 2b illustrates the synthesis of the C-glucosides commencing with an appropriately protected D-glucal XXX (see Synlett 2004, pp. 1235-1238; Org. Lett. 2003, 5, pp. 405-2408 and references quoted therein for analogous approaches). The protected D-glucal XXX is metallated to yield the D-glucal derivative XXXI wherein M denotes a lithium, magnesium, zinc, indium, boron, tin, silicon or chromium moiety; in particular lithium, magnesium halide, zinc halide, indium halide, boronic acid, boronic acid ester. Metalation of glucal XXX at C-1 may be accomplished by deprotonation with a strong base. Strong bases capable of deprotonating the glucal may be lithium bases such as e.g. n-butyl lithium, sec-butyl lithium or tert-butyl lithium. The C-1 lithiated glucal thus obtained may be transmetalated with different electrophilic metal sources delivering the corresponding C-1 metalated glucal derivative. Metal species suitable for the subsequent transformation, coupling with the aglycon moiety, are derived from e.g. lithium, magnesium, zinc, indium, boron, tin, silicon, and chromium. The transmetalation of the glucal compound from lithium to one of the metals mentioned may be conducted with the corresponding e.g. halides such as chloride, bromide and iodide, sulfonates such as e.g. trifluoromethanesulfonate, and alcoxides such as e.g. methoxide, ethoxide, propoxide and isopropoxide of the metal species to be introduced. Depending on the metal transmetalated to the metal may bear more than one glucal residue such as in the corresponding triglucal indium or diglucal zinc. The corresponding monoglucal substituted metal derivatives are employable as well. The metalation of glucal with a strong base, in particular a lithium base, is preferably performed in inert solvents such as e.g. tetrahydrofuran, ether, dioxane, dimethoxyethane, hexane, and toluene. Preferred temperatures are in the range between −80° C. and 50° C. The transmetalation may be conducted in the same solvents depending on the electrophilic metal species in the same temperature range. Among the electrophilic metal species usable in the transmetalation the following are among the most appropriate: trialkylchlorostannane, tetrachlorostannane, trialkylchlorosilane, trialkoxychlorosilyl chloride or bromide, boron trichloride, trialkyl borates, dialkylchloroborane, indium trichloride, zinc chloride, triflate or bromide, magnesium chloride or bromide. This compilation is by no means meant to restrict the employable metal electrophiles to the ones mentioned but is supposed to give an idea of electrophiles that can be used. In the above and below described reactions the protecting groups R2 are preferably chosen in view of their stability under basic conditions, in particular the groups R2 independently of each other denote —SiRaRbRc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SiRaRb, wherein Ra, Rb, Rc are defined as hereinbefore, preferably denote isopropyl.
The metalated glucal derivative of the formula XXXI thus obtained may be coupled with the agylcon V wherein the group X denotes a leaving group, preferably selected from the group consisting of chlorine, bromine, iodine, sulfonate such as e.g. trifluoromethane-sulfonate, tosylate, benezenesulfonate, and mesylate, chlorosulfonate, sulfonic acid or salts thereof, hydroxycarbonyl or salts thereof, nitrile, and diazonium salts. The coupling reactions are preferably carried out in the presence of a transition metal catalyst such as e.g. salts, complexes or elemental modifications of palladium, copper, iron, and nickel. Complexes can be formed in situ or prior to the addition of the transition metal to the reaction mixture. The ligands in the complexes of the transition metal may be e.g. triarylphosphine, aryldialkyl-phosphine, trialkylphosphine, phosphite, 1,3-disubstituted dihydroimidazolium carbene, 1,3-disubstituted imidazolium carbene, and alkenes. The reaction is preferably carried out in an inert organic solvent or mixtures thereof. Suitable solvents may be e.g. tetrahydrofuran, dioxane, dimethoxyethane, hexane, toluene, benzene, dimethylformamide, dimethylacetamide, N-methylpyrrolidinone, acetone, ethyl acetate, water, methanol, ethanol, propanol, isopropanol, ethylene glycol, polyethylene glycol. The coupling reactions are preferably carried out between −80° C. and 180° C., more preferably at −20° C. to 120° C. The concluding synthetic step in Scheme 2b is the formal addition of water to the double bond in the glucal moiety. This process may be done by e.g. hydroboration that results in the formation of the 2-boron-2-desoxy glucose derivative that can be converted to the corresponding glucose compound by oxidation of the carbon-boron bond. Suitable boranes for the hydroboration are e.g. borane or ether, thioether or amine adducts thereof, alkylboranes or dialkylboranes such as e.g. hexylborane, thexylborane, diethylborane and 9-BBN, pinacolborane, catecholborane, halo or dihaloborane such as e.g. dichloroborane. The hydroboration may be conducted in e.g. tetrahydrofuran, hexane, cyclohexane, ether, toluene, benzene, dichloromethane. A preferred temperature range is between −50° C. and 150° C., preferably between −20° C. and 50° C. The oxidative cleavage of the carbon-boron bond may be performed with an oxidizing reagent such as e.g. hydrogen peroxide, tert-butyl hydrogen peroxide, sodium perborate, and trialkylamine N-oxide. Depending on the oxidizing reagent the reaction is advantageously carried out in the presence of a base such as e.g. sodium hydroxide. The reaction is preferably carried out in an inert organic solvent or mixtures thereof. Preferred solvents are selected from among tetrahydrofuran, water, alcohols, dioxane, diemethoxyethane, cyclohexane, hexane, toluene, dichloromethane and mixtures thereof. A preferred temperature range is between −30 to 150° C., preferably between 0 to 110° C. An alternative to the hydroboration in order to add water to the double bond is the combination of epoxidation or dihydroxylation of the double bond and reduction of the resultant anomeric carbon-oxygen bond. Suitable oxidizing reagents for the epoxidation are e.g. dimethyldioxirane, trifluordimethyldioxirane, 3-chloroperoxybenzoic acid, hydrogen peroxide and oxygen in the presence of a transition metal catalyst. Another suitable oxidizing agent is peroxomonosulfuric acid, peroxodisulfuric acid and salts thereof, in the presence of at least one ketone, in particular triple salts of the formula 2 KHSO5×KHSO4×K2SO4 which are commercially available, for example under the brand names OXONE® (trademark E.I. du Pont de Nemours) and CAROAT® (trademark Degussa, Peroxid-Chemie GmbH & Co. KG, Dr.-Gustav-Adolph-Str. 3, D-82049 Pullach, Germany) in combination with a ketone, preferably acetone. Dihydroxylation can be accomplished with e.g. osmium tetroxide and dipotassium osmium tetroxide preferably in the presence of a co-oxidant such as e.g. potassium hexacyano-ferrate, hydrogenperoxide, and N-methylmorpholine N-oxide; hydrolytic opening of the oxirane resulting from the epoxidation gives also access to the dihydroxylation product. The oxidations may be conducted in inert organic solvents or mixtures thereof such as e.g. dichloromethane, tetrahydrofuran, ether, hexane, cyclohexane, dioxane, acetone, ethyl acetate, acetonitrile, water, alcohols and mixtures thereof. A preferred temperature range is between −80° C. and 100° C., preferably between −50° C. and 50° C. Reduction of the anomeric carbon-oxygen bond of the oxirane or dihydroxylation product may be accomplished with reducing agents such as e.g. trialkylsilanes such as e.g. triethylsilane, borohydrides such as e.g. sodium borohydride and aluminum hydrides such as e.g. diisobutylaluminum hydride. Depending on the reducing agent the presence of a Lewis acid such as e.g. boron trifluoride etherate, zinc chlorides, trimethylsilyl chloride or triflate, alkyl-, dialkyl- or aluminum halide, copper triflate, and Brønsted acids such as e.g. hydrochloric acid, acetic acid, alkyl- or arylsulfonic acids, trifluoroacetic acid is necessary or at least advantageous. Dichloromethane, acetonitrile, tetrahydrofuran, ether, hexane are among the preferred solvents. A preferred temperature range is between −80° C. and 120° C. Hydrogen in combination with a transition metal catalyst such as e.g. palladium on carbon, Raney-nickel, and palladium hydroxide may be used as well.
Subsequently, the product of the formula XXXIII may be transferred into the product of the formula I by cleaving, in particular hydrolysing, the protective groups R2 not being hydrogen, advantageously employing methods as described hereinbefore.




Scheme 2c illustrates an alternative access to C-glucosides starting from the glucal XXX (see e.g. Synlett 2003, pp. 870-872; Tetrahedron 2002, 58, pp. 1997-2009 and references quoted therein for analogous approaches). Epoxidation with an appropriate oxidizing reagent transforms the glucal XXX into the corresponding glucaloxide XXXIV. Suitable reaction conditions for this transformation have already been described for the analogous conversion of glucal XXXII shown in Scheme 2b. Among the oxidizing agents described there dimethyldioxirane and trifluorodimethyidioxirane generated separately or in situ are preferred. Said oxidizing agents may be obtained with e.g. peroxomonosulfuric acid, peroxodisulfuric acid and salts thereof, in the presence of at least one ketone, in particular with triple salts of the formula 2 KHSO5×KHSO4×K2SO4 which are commercially available, for example under the brand names OXONE® (trademark E.I. du Pont de Nemours) and CAROAT® (trademark Degussa, Peroxid-Chemie GmbH & Co. KG, Dr.-Gustav-Adolph-Str. 3, D-82049 Pullach, Germany) in combination with a ketone, preferably acetone. The reaction is preferably carried out at temperatures in the range between −80 and 0° C. in an inert organic solvent or mixtures thereof. Preferred solvents are selected from the group consisting of dioxan, 1,2-dimethoxyethane, toluene, hexane, tetrahydrofuran, diethylether, dichloromethane and mixtures thereof. In the above and below described reactions the protecting groups R2 are preferably independently of each other selected from the group consisting of C1-4-alkylcarbonyl, C1-4-alkyloxycarbonyl, arylmethyl and RaRbRcSi, wherein aryl, Ra, Rb and Rc are defined as hereinbefore.
The ensuing reaction, epoxide opening with a metalated aglycon of the formula VI in which M denotes a lithium, magnesium, zinc, indium, aluminum or boron moiety, affords the desired C-glucoside. For this transformation the preferred meaning of M is lithium, magnesium halide, zinc halide, indium halide, aluminum halide, dialkylaluminum halide or boronic acid compound. The synthesis of the lithium or magnesium derivative of compound VI has been detailed in Scheme 2a, whereas the transmetalation of these compounds to one of the alternative metal species may be done in analogy to the transmetalation of the lithiated glucal to the same metal derivatives presented in Scheme 2b. The epoxide opening reaction may take place without an adjuvant or in the presence of a transition metal salt or complex such as e.g. copper cyanide or halide or in the presence of a Lewis acid such as e.g. borontrifluoride etherate or trimethylsilyl-chloride or triflate. Suitable inert solvents may be e.g. acetone, ether, tetrahydrofuran, acetonitrile, dichloromethane, toluene, hexane and mixtures thereof. A preferred temperature range is between −80° C. to 60° C.
Subsequently the product of the formula XXXIII may be transferred into the product of the formula I by cleaving, in particular hydrolysing, the protective groups R2 not being hydrogen, advantageously employing methods as described hereinbefore.




A glucose derivative XXXV bearing a potential leaving group Hal at the anomeric carbon may be utilized as starting material for the coupling with a metalated aryl aglycon VI as well (see J. Carbohydr. Chem. 1994, 13, pp. 303-321 and references quoted therein for analogous approaches). Suitable leaving groups Hal may be halides, alcoxides, acyl groups such as carboxylates and carbonates; in particular F, Cl, Br, C1-3-alkylcarbonyloxy, C1-3-alkyloxy-carbonyloxy or C1-3-alkyloxy, such as e.g. Cl, Br, methoxide, acetate and methylcarbonate. Suitable metals M attached to the aryl part are e.g. lithium, magnesium as e.g. magnesium halide, zinc as e.g. zinc halide, indium as e.g. indium dihalide, boron as e.g. boronic acid or boronic acid ester. The preparation of these metalated aryl compounds from the corresponding halogenated aromats has been described in Scheme 2c. The substitution reactions can be run without or in the presence of an additional Lewis acid such as e.g. boron trifluoride etherate, trimethylsilyl chloride or triflate depending on the metal species and glucosyl donor employed. The reaction is preferably carried out in an inert organic solvents or mixtures thereof. The preferred solvent is preferably chosen in view of the metalated aglycon, glucosyl donor and adjuvants needed; the following solvents may be advantageous: tetrahydrofuran, dioxane, toluene, hexane, ether, N-methylpyrrolidinone, dimethylacetamide, dimethylformamide, acetonitrile, dichloromethane and mixtures thereof. The coupling reaction is usually conducted between −80° C. and 120° C., preferably at −60° C. to 60° C. In the above and below described reactions the protecting groups R2 are preferably independently of each other selected from the group consisting of C1-4-alkylcarbonyl, C1-4-alkyloxycarbonyl, arylmethyl and RaRbRcSi, wherein aryl, Ra, Rb and Rc are defined as hereinbefore.
Subsequently the product of the formula II may be transferred into the product of the formula I by cleaving, in particular hydrolysing, the protective groups R2 not being hydrogen, advantageously employing methods as described hereinbefore.
The synthesis of haloaromatic compound V may be carried out using standard transformations in organic chemistry or at least methods known from the specialist literature in organic synthesis (see inter alia J. March, Advanced Organic Reactions, Reactions, Mechanisms, and Structure, 4th Edition, John Wiley & Sons, Chichester/New York/Brisbane/Toronto/Singapore, 1992 and literature cited therein). The synthesis strategies described in the following provide a demonstration of this, by way of example.
In the following schemes
X denotes bromine or iodine,
Alk denotes C1-4-alkyl,
R denotes C1-4-alkyl, C1-4-alkoxy, CF3, aryl or aryl-C1-3-alkyl, wherein aryl-groups may be mono- or polysubstituted with L1;
R1 is as defined hereinbefore; and
L1 is as defined hereinbefore;
unless indicated otherwise.
Scheme 3 displays the synthesis of aglycon V starting from benzophenone derivative IX that can be prepared from a benzoic acid derivative and a phenylalkylether or a metalated phenylalkylether (see Schemes 5, 8, and 9). The first step is the cleavage of the ether moiety in compound IX that can be accomplished under neutral, acidic and basic conditions. Suitable acidic reagents for this transformation are e.g. boron trichloride or tribromide or triiodide, trimethylsilyl iodide, aluminum chloride or bromide, hydrobromic acid, hydrochloric acid, cerium chloride, trifluoroacetic acid, and trifluoromethylsulfonic acid that may be used in concert with a nucleophile such as e.g. metal halides such as e.g. sodium iodide, water, alkylthiols, thioanisole, and dialkylsulfides, that may scavenge the departing alkyl group. Depending on the acid used solvents selected from the group consisting of halogenated hydrocarbons, such as e.g. dichloromethane, chloroform or 1,2-dichloroethane, acetonitrile, toluene, hexane, acetic acid and combinations thereof are preferred. Reactions without additional solvent are also feasible. The reactions are generally carried out at −90 to 150° C., preferably at −80 to 50° C. Cleavage under neutral or basic conditions can be done e.g. with metal thiolates such as e.g. sodium sulfide, sodium ethanethiolate, sodium trimethylsilyl-thiolate, potassium thiophenolate, sodium cyanide, and lithium iodide in solvents such as e.g. dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-oxohexahydropyrimidine, N-methyl-pyrrolidone, tetrahydrofuran, collidine, and quinoline at temperatures between 0 and 250° C., preferably at 50 to 180° C. The second step outlined in Scheme 3 comprises the attachment of residue R1 to the phenolic oxygen of compound VIII. This transformation can be carried out under basic conditions as classical nucleophilic substitution reaction. Accordingly, the phenol is deprotonated by a base to from the corresponding phenolate. Suitable bases are e.g. group I or II metal salts, in particular carbonates, hydroxides, alkoholates such as e.g. methoxide, ethoxide or tertbutoxide, and metal hydrides such as e.g. sodium hydride. The reaction can be conducted in polar and non-polar solvents as well as without solvent, preferably in alcohols such as e.g. ethanol, isopropanol or butanol, acetone, water, dimethylformamide, dimethylacetamide, N-methylpyrollidone, dimethylsulfoxide, tetrahydrofuran, dichloromethane and mixtures thereof. The phenolate obtained then is reacted with an electrophile of R1 at temperatures between 20 and 180° C., preferably between 40 and 120° C. Suitable electrophiles of R1 are e.g. halides, such as chlorides, bromides or iodides, alkylsulfonates such as e.g. methylsulfonate, trifluoromethanesulfonate, arylsulfonates such as e.g. 4-bromophenylsulfonate, 4-methylphenylsulfonate or phenylsulfonate. An alternative approach to attach R1 to the phenol VIII is the addition of the phenol VIII to a group R1 that bears an appropriately situated C═C double bond. This reaction may be conducted in the presence of a Brønsted acid such as e.g. trifluoro-methanesulfonic acid, hydrochloric acid, sulfuric acid, or a transition metal catalysts such as e.g. platinum, ruthenium, palladium, or gold salts or complexes thereof; preferred salts are triflate, chloride, bromide and iodide (see e.g. Cai-Guang Yang and Chuang He; J. Am Chem. Soc. 2005, 127, and references quoted therein). The solvent most appropriate for the addition depends on the acid or transition metal that is employed. Solvents such as e.g. toluene, benzene, dichloromethane, 1,2-dichloroethane, acetonitrile, tetrahydrofuran, dimethylacetamide, N-methylpyrrolidone, hexane, and ethyl acetate may be suited. The reaction is carried out at 0 to 200° C., preferably at 20 to 140° C. Scheme 3 concludes with the reduction of benzophenone VII to furnish aglycon V. Proper reducing agents for this conversion are e.g. silane such as e.g. Et3SiH and triisopropylsilane, borohydride such as e.g. NaBH4, and aluminum hydride such as e.g. LiAlH4 in the presence of a Lewis acid such as for example BF3*OEt2, tris(pentafluorophenyl)borane, trifluoroacetic acid, hydrochloric acid, aluminum chloride, or InCl3. The reactions are preferably carried out in solvents such as e.g. halogenated hydrocarbons such as dichloromethane and 1,2-dichloroethane, toluene, benzene, hexane, acetonitrile and mixtures thereof at temperatures of −30 to 150° C., preferably at 20 to 100° C. Reductions with hydrogen in the presence of a transition metal catalyst such as e.g. Pd on charcoal are another possible method of synthesis but might be less suited here due to competing reduction processes in the rest of the molecule. Reductions according to Wolff-Kishner or variants thereof are also conceivable. Hence, the ketone is converted with hydrazine or a derivative thereof such as e.g. 1,2-bis(tert-butyldimethylsilyl)hydrazine into the hydrazone which breaks down under strongly basic reaction conditions and heating to liberate the diphenylmethane V and nitrogen. The reaction may be carried out in one pot or after isolation of the hydrazone or a derivative thereof in two separate reaction steps. Suitable bases include e.g. KOH, NaOH or KOtBu in solvents such as e.g. ethyleneglycol, toluene, DMSO, 2-(2-butoxyethoxy)ethanol or tert-butanol; solvent-free reactions are also possible. The reactions may be performed at temperatures between 20 and 250° C., preferably between 80 and 200° C. An alternative to the basic conditions of the Wolff-Kishner reduction is the Clemmensen reduction which takes place under acidic conditions, which may also be used here if no concurrent dehalogenation occurs.




Scheme 4 outlines a slightly different approach to the synthesis of aglycon V compared with Scheme 3. Nevertheless, the ether cleavage and the ensuing etherification delineated in Scheme 4 can principally be carried out under reaction conditions analogous to the synthesis described above with respect to the compounds VIII and VII.




Scheme 5 describes the assembly of aglycon V starting from the known benzoyl chloride XII and phenylether derivative XII. The first step, the preparation of benzophenone VII, can be characterized as Friedel-Crafts or Friedel-Crafts-type acylation, a well-known and widely used method in organic synthesis. In principal, the benzoyl chloride XII may be replaced by other benzoic acid derivatives such as e.g. benzoyl anhydrides, esters, or benzonitriles. This classic reaction has a wide substrate scope and is commonly carried out in the presence of a catalyst such as e.g. AlCl3, FeCl3, iodine, iron, ZnCl2, sulfuric acid, or trifluoromethanesulfonic acid which is used in catalytic or stoichiometric amounts. The reactions are preferentially performed in chlorinated hydrocarbons such as e.g. dichloromethane or 1,2-dichloroethane, in hydrocarbons such as e.g. hexane at temperatures ranging from −30 to 140° C., preferably at 30 to 100° C. However, other solvents and solvent mixtures and also solvent-free reactions or reactions in a microwave oven are also possible. The second reaction step in Scheme 5 is analogous to the final reaction in Scheme 3 as described hereinbefore.




Scheme 6 illustrates an alternative synthesis of the aglycon V via a Friedel-Crafts-type alkylation of phenylether XIII with benzyl electrophile XIV (see Angew. Chem. 2005, 117, pp. 242-246 and Syn. Commun. 2004, 34, pp. 3161-3165 and references quoted therein). The reaction is commonly conducted in the presence of a catalyst, in particular of a Lewis acid such as e.g. scandium chloride, zinc chloride, aluminium chloride or boron trifluoride, of a Brønsted acid such as e.g. sulfuric acid, hydrochloric acid or hydrogenfluoride, of a lanthanide salt such as e.g. cerium sulfate or ytterbium chloride, of an actinide salt, of a transition metal salt or of a complex such as e.g. IrCl3*nH2O, RhCL3*nH2O, H2[PtCl6]*6H2O or H2[PdCl6]*6H2O. The catalysts can be applied in stoichiometric or excess quantities though in many cases substoichometric or even catalytic amounts are sufficient. The reactions are usually carried out with an excess of aromatic compound XIII relating to the benzyl electrophile without solvent; though inert solvents such as e.g. halogenated hydrocarbons or hydrocarbons can be employed as well. The reaction is generally conducted at temperatures between 0 and 200° C., preferably at 20 to 140° C.




The approach presented in Scheme 7 starts with the synthesis of phenylether XVI from monosubstituted phenol XV that can be conducted analogously to the synthesis of the etherification shown in Scheme 3. In the second step of Scheme 7 the residue Z2 is exchanged for a metal or substituted metal residue. Lithium or magnesium substituted aromatic compounds XVII may be prepared from chlorinated, brominated, or iodinated aromatic compounds XV in the same manner as for the metalated aglycon VI described in Scheme 2a. The corresponding boron substituted compound such as e.g. boronic acid, boronic acid ester, or dialkylarylborane is accessible from these metalated phenyl groups XVII by the reaction with an appropriate boron electrophile such as e.g. boronic acid ester, haloboronic acid ester, alkylbornic acid ester, dialkylboronic acid ester, trihaloborane, and derivatives thereof. In addition, the boronylated aromatic compound XVII may also be prepared from the corresponding chlorinated, brominated, iodinated, or pseudohalogenated such as e.g. trifluoromethanesulfonated and tosylated precursor and a diboron compound such e.g. bis(pinacolato)diboron and bis(neopentyl-glycolato)diboron, or a borane such as e.g. pinacolborane through a transition metal catalyzed reaction (see e.g. Tetrahedron Lett. 2003, p. 4895-4898 and references quoted therein). The transition metal is e.g. palladium that is employed as element, salt, or complex; common Pd sources are e.g. palladium on charcoal, palladium acetate, palladium chloride, palladium bromide, palladium dibenzylideneacetone that are used as such or in combination with a ligand such as e.g. phosphines such as e.g. tricyclohexylphosphine, triphenylphosphine, 1,1′-bis(diphenyl-phosphino)ferrocene, and tritolylphosphine, or phosphites or imidazolium salts such as 1,3-diaryl or dialkylimidazolium halides or pseudohalides or dihydroimidazolium salts. The resulting complex of the transition metal and the ligand may be prepared in situ or in a separate step. The reactions are preferably conducted in the presence of a base such as e.g. triethylamine, potassium acetate, potassium carbonate, potassium phosphate, sodium hydroxide, triethylamine or ethyldiisopropylamine, in solvents such as e.g. acetonitrile, tetrahydrofuran, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methyl-pyrrolidone, dioxane, toluene and mixtures thereof at 0 to 180° C., preferably at 60 to 140° C. The lithium or magnesium substituted phenyl compounds XVII add spontaneously to benzaldehyde XVIII furnishing diarylmethanol XIX. This reaction can be performed in solvents such as diethylether, tetrahydrofuran, toluene, dichloromethane, dioxane, hydrocarbons such as e.g. hexane and mixtures thereof at temperatures ranging from −100 to 20° C., preferably at −80 at 0° C. Aryl boronic acids XVII can be added to the benzaldehyde derivative XVIII by means of a rhodium catalyzed reaction furnishing the respective diarylmethanol XIX (see e.g. Adv. Synth. Catal. 2001, p. 343-350 and references quoted therein). The concluding step in Scheme 7 is the reduction of the diarylmethanol XIX to the aglycon V. Suitable reducing agents for this transformation are e.g. NaBH4, LiAlH4, iBu2AlH, Et3SiH, iPr3SiH or Ph2SiClH. The reaction is usually carried out in the presence of a Lewis acid such as for example BF3*OEt2, trifluoroacetic acid, hydrochloric acid, InCl3, or AlCl3 in a solvent such as halogenated hydrocarbons such as e.g. dichloromethane or 1,2-dichloro-ethane, toluene, hydrocarbons such as e.g. hexane, acetonitrile or mixtures thereof at temperatures of −80 to 150° C., preferably at −20 to 100° C. Reductions with hydrogen in the presence of a transition metal catalyst such as e.g. Pd on charcoal are principally also possible though particular care has to be taken using this method to preserve full integrity of the rest of the molecule.




The synthesis sketched in Scheme 8 begins with the addition of metalated phenylether derivative XXI to benzoic acid or a derivative thereof (XX) such as benzoic acid esters, benzoic acid anhydrides, benzamides such as e.g. of the Weinreb type, benzonitriles, or benzoyl chlorides to deliver the benzophenone VII. Lithium or magnesium derivatized phenylethers XXI can principally be added to benzamides, benzoic acid esters, benzoyl chlorides, benzoic acid anhydrides, and benzonitriles to give the desired benzophenone VII while only lithiated phenylethers react with benzoic acids to produce the same compound. The latter reaction can be carried out in e.g. tetrahydrofuran, dioxane, diethylether, benzene, toluene, hexane and mixtures thereof at −80 to 100° C., preferably at −30 to 40° C. Benzonitriles and benzamides such as e.g. the corresponding Weinreb-type amide or a close derivative thereof are preferentially reacted in tetrahydrofuran, dioxane, toluene, hexane, ether and mixtures thereof at temperatures ranging from −90 to 50° C., preferably at −80 to 20° C. Benzoyl chlorides or anhydrides and benzoic acid esters are commonly employed in inert solvents such as tetrahydrofuran, diethylether, toluene, dichloromethane, dioxane, hydrocarbons such as e.g. hexane or mixtures of them at low temperatures, preferably at −80 to 0° C. To prevent double addition of the organometal compound to benzoyl chlorides, benzoyl anhydrides or benzoic acid esters to produce the corresponding alcohol the addition may superiorly carried out in the presence of a trapping reagent such as e.g. trimethylsilyl chloride. An alternative choice to prevent double addition in the cases mentioned may be transmetalation to a less reactive nucleophile XXI. Suitable metals are e.g. zinc, cerium, chromium, or indium that are introduced as e.g. chloride, bromide, iodide or pseudo halide salt such as e.g. trifluoromethanesulfonate to transmetalate the lithium or magnesium compound to give the corresponding less reactive, more selective metal compound XXI. The transmetalation is preferentially conducted in the solvent wherein the initial organometal compound is generated (see above) at temperatures of −90 to 0° C. Transmetalation is not restricted to the metals mentioned and the boron derivatized compounds already described in Scheme 7 but can also furnish e.g. stannanes and silanes. Some of the transmetalated compounds react spontaneously with the corresponding benzoyl electrophile, particularly benzoyl chloride and anhydride, but the addition of a transition metal catalyst may be advantageous. In particular arylboronic acids, esters thereof, dialkylarylboranes, aryltrifluoroborates, stannanes, silanes, indium, chromium, and zinc derivatized compounds XXI couple with benzoyl chloride derivatives XX mediated by a transition metal such as e.g. palladium, copper, iron, nickel, that may be used as element or salt such as e.g. acetate, chloride, bromide, iodides, acetylacetonate, trifluoromethanesulfonate, and cyanide in combination with ligands such as e.g. phosphites, phosphines such as e.g. triphenylphosphine, tricyclohexylphoshine, tritolylphosphine, 1,3-substituted imidazolium or dihydroimidazolium compounds delivering diarylketones VII. The active transition metal species can be prepared prior to the addition to the coupling partners but also in the presence of the reaction partners in situ. Suitable solvents are e.g. dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, dioxane, ether, hexane, toluene, tetrahydrofuran, dichloromethane or mixtures thereof that are preferably used at −50 to 150° C., particularly preferably at 0 to 120° C. The concluding conversion to get to the aglycon V has been detailed above and can be applied analogously here.




According to the Scheme 9 the metalated aryl groups XXIII that can be synthesized as described above can also be reacted with benzyl electrophiles XXII such as e.g. benzyl chlorides, bromides, iodides, sulfonates, phosphonates, carbonates, or carboxylates affording diarylmethanes V. Lithium or magnesium derivatized phenyl compounds XXIII are reacted favorably (but not always necessarily) in the presence of a transition metal such as e.g. copper, iron, nickel, or palladium (see e.g. Org. Lett. 2001, 3, 2871-2874 and Tetrahedron Lett. 2004, p. 8225-8228 and references cited therein). Usable solvents are e.g. tetrahydrofuran, dioxane, toluene, dichloromethane, hexane, ether or mixtures thereof. The range of reaction temperature is from −90 to 20° C., preferably from −80 to −20° C. The transition metal can be employed as element such as e.g. on charcoal, as salt such as e.g. acetate, acetylacetonate, cyanide, chloride, bromide, iodide, trifluoromethanesulfonate, or as complex such as e.g. with dibenzylideneacetones, phosphites, phosphines such as e.g. triphenylphosphine, tricyclohexylphoshine, and tritolylphosphine, or with carbenes derived from e.g. 1,3-disubstituted imidazolium or dihydroimidazolium compounds. The active transition metal species can be prepared in situ in the presence of the reaction partners or prior to the addition to the coupling partners. Arylmetal compounds XXIII bearing e.g. boron, tin, silicon, zinc, indium, chromium residue are preferably used in combination with a transition metal catalyst. Suitable metal compounds of these types are e.g. boronic acids, boronic acid esters, dialkylboranes, trifluoroborates, trialkylstannanes, trichlorostannanes, trialkoxysilanes, dihaloindium substituted or halozinc substituted compounds. The metal substituted compounds XXIII may be synthesized as described before by transmetalation from the corresponding lithium or magnesium derivatized compounds or as in the case of zinc, chromium and indium also directly from the corresponding arylchloride, bromide or iodide by insertion of the elemental metal. The coupling reaction with the benzyl electrophile may be conducted in tetrahydrofuran, dimethylformamid, dimethylacetamid, N-methyl-pyrrolidone, dimethylsulfoxide, toluene, ether, dioxane, dichloromethane, acetonitrile, hexane, water, alcohols such as e.g. ethanol, isopropanol, or mixtures thereof at reaction temperatures of −30 to 180° C., preferably at 20 to 150° C. Depending on the metal an additional base such as e.g. triethylamine, ethyldiisopropylamine, cesium or potassium or sodium or lithium carbonate, potassium or sodium or lithium tertbutoxide, potassium phosphate, potassium or cesium or tetrabutylammonium fluoride, sodium hydroxide, thallium hydroxide, sodium methoxide and/or other additives such as e.g. lithium chloride, silver salts such as e.g. carbonate or oxide, tetrabutylammonium bromide, and sodium bromide may be advantageous or even essential (e.g. M. Schlosser, Organometallics in Synthesis, John Wiley & Sons, Chichester/New York/Brisbane/Toronto, 1994 and references cited therein).




The Scheme 10 shows the access to aglycon V via intermediate XXVI that can be prepared according to Scheme 8. If Z5 represents halogen such as F, intermediate XXVI may alternatively be prepared by Friedel-Crafts-acylation according to scheme 5. Replacement of Z5 in compound XXVI by O—R1 may be achieved via different methods. In the cases in which Z5 preferably denotes fluorine, chlorine, iodine, trifluormethylsulfonate O—R1 may be attached according to a nucleophilic substitution on an aromatic ring in which R1—OH or an anion thereof replaces Z5 in an addition/elimination sequence. The reaction is usually conducted in solvents such as e.g. dimethylformamide, dimethylacetamide, dimethylsulfoxide, tetrahydrofuran, dioxane, tertbutanol, toluene, N-methylpyrrolidone, water, alcohol or mixtures thereof in the presence of a base such as e.g. lithium or sodium or potassium tertbutoxide, sodium or potassium or cesium carbonate, sodium or potassium hydroxide, tripotassium phosphate, triethylamine, ethyldiisopropylamine, or diazabicycloundecene at temperatures ranging from 0 to 180° C., preferably at 40 to 140° C. R1—OH may also be used as solvent and may be deprotonated with e.g. sodium hydride or sodium to form the alkoxide prior the addition of compound XXVI. To enhance the nucleophilicity of R1—O-metal the addition of crown ethers such as e.g. 18-crown-6 may be useful. The coupling of isolatable intermediate XXVI and R1—OH may also be conducted in the presence of a transition metal salt or complex such as e.g. derived from Pd or Cu (Ullmann or Ullmann-type reaction). Here Z5 preferentially stands for iodine or trifluoromethansulfonate. The same solvents, bases, additives, and temperatures described for the uncatalyzed reaction may be used for the catalyzed reaction except for that the latter is preferably executed under an inert gas atmosphere such as argon or nitrogen. The catalyst is usually employed as element as such or on charcoal, as a salt such as e.g. chloride, bromide, acetate, cyanide, or as a complex with ligands such as e.g. phosphites, phosphines, dibenzylideneacetone, 1,3-disubstituted imidazole or dihydroimidazole carbenes. If Z5 denotes arylboronic acid or trifluoroborate R1—OH may be attached via a copper(II) catalyzed reaction with a copper source such as e.g. copper(II) acetate in the presence of a base such as e.g. triethylamine or pyridine in solvents such as e.g. tetrahydrofuran, dichloromethane, 1,2-dichloroethane, acteonitrile, dioxane, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. The reaction may be carried out with stoichiometric amounts of copper catalyst or in the presence of a co-oxidant such as e.g. oxygen, pyridine-N-oxide, or tetramethylpiperidineoxide with only catalytic amounts of the catalyst. Dry solvents and the presence of drying agents such as e.g. molecular sieves are advantageous (see e.g. Angew. Chem. 2003, 115, pp. 5558-5607 and references quoted therein).




The Scheme 11 shows a preferred access to the aglycon V which corresponds to the Scheme 10 whereby the intermediate XXVI is prepared by Friedel-Crafts-acylation according to Scheme 5. The Scheme 11 and the following sections describe preferred conditions and embodiments of the seventh aspect of this invention.
The assembly of aglycon V starts from the known benzoyl chloride XII and halobenzene XXVII. The substituent X preferably denotes a bromine or iodine atom. A preferred meaning of the substituent Z5 is a fluorine atom. The first step, the preparation of benzophenone XXVI, can be characterized as Friedel-Crafts or Friedel-Crafts-type acylation, a well-known method in organic synthesis. In principal, the benzoyl chloride XII may be replaced by other benzoic acid derivatives such as e.g. benzoyl anhydrides, esters, or benzonitriles. This reaction is advantageously carried out in the presence of a catalyst such as e.g. AlCl3, FeCl3, iodine, iron, ZnCl2, sulfuric acid, or trifluoromethanesulfonic acid, all of which are used in catalytic or up to stoichiometric amounts. A preferred catalyst is AlCl3. The reaction may be performed with or without additional solvents. Preferred additional solvents are chlorinated hydrocarbons such as e.g. dichloromethane or 1,2-dichloroethane, hydrocarbons such as e.g. hexane or mixtures thereof. According to a preferred embodiment the reaction is carried out using an excess of the halobenzene XXVII which additionally serves as a solvent. Preferred temperatures during the reaction range from −30 to 140° C., preferably from 30 to 85° C. After completion of the reaction the reaction mixture may be quenched with water. Preferably the organic solvents are removed. The intermediate XXVI may be isolated, preferably by crystallization, for example from water.
The second reaction step in Scheme 11 which is the replacement of Z5 by O—R1 is analogous to the second reaction step in Scheme 10 as described hereinbefore. According to a preferred embodiment O—R1 is attached according to a nucleophilic substitution on an aromatic ring in which R1—OH or an anion thereof replaces Z5 in an addition/elimination sequence. The reaction is advantageously conducted in a solvent such as e.g. dimethylformamide, dimethylacetamide, dimethylsulfoxide, tetrahydrofuran, dioxane, tertbutanol, toluene, heptane, N-methylpyrrolidone, water, alcohol or a mixture thereof. Preferred solvents are selected from dimethylformamide, tetrahydrofuran and dimethylacetamide.
This reaction is preferably carried out in the presence of a base such as alkali C1-4-alkoxides, alkali carbonates, alkali hydroxides, alkali phosphates, tri(C1-3 alkyl)amines and other N-containing organic bases. Examples of preferred bases are lithium or sodium or potassium tertbutoxide, sodium or potassium or cesium carbonate, sodium or potassium hydroxide, tripotassium phosphate, triethylamine, ethyldiisopropylamine, sodium bis(trimethylsilyl)amide (NaHMDS), diazabicycloundecene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO) or mixtures thereof. More preferred bases are selected from sodium or potassium tertbutoxide, sodium or potassium hydroxide, cesium carbonate, a mixture of cesium carbonate and potassium carbonate, or mixtures thereof. The amount of the base is preferably in the range from 1 to 5 mol base per mol of intermediate XXVI. In case the base is a carbonate, phosphate or mixtures thereof, the total amount of the base is more preferably in the range from 2 to 4 mol base, most preferably about 3 mol base per mol of intermediate XXVI.
The reaction is preferably carried out at temperatures ranging from about −20 to 60° C., more preferably from about −10 to 40° C., even more preferably from about 0 to 30° C.
The intermediate VII may be isolated from the reaction mixture, preferably by crystallization, for example from a mixture of ethanol and water.
The synthetic route according to Scheme 11 concludes with the reduction of benzophenone VII to furnish aglycon V. Suitable reducing agents for this conversion are silanes, in particular tri(C1-3-alkyl)silanes, such as e.g. triethylsilane, dimethylethylsilane and triisopropylsilane, borohydrides such as e.g. NaBH4, and aluminum hydrides such as e.g. LiAlH4 in the presence of a Lewis acid such as for example BF3*OEt2, tris(pentafluorophenyl)borane, trifluoroacetic acid, hydrochloric acid, aluminum chloride, or InCl3. A particularly preferred reducing agent is Et3SiH in the presence of a Lewis acid such as for example BF3*OEt2. Another particularly preferred reducing agent is NaBH4 in the presence of a Lewis acid such as for example trifluoroacetic acid.
The amount of the reducing agent, in particular of Et3SiH, is preferably from about 1 to 5 mol, even more preferably from about 2 to 4 mol, most preferably about 3 mol per mol of benzophenone VII. The amount of the Lewis acid, in particular of BF3*OEt2, is preferably from about 1 to 5 mol, even more preferably from about 1 to 3 mol per mol of benzophenone VII.
The reduction reaction is preferably carried out in a solvent such as halogenated hydrocarbons, for example dichloromethane and 1,2-dichloroethane, toluene, benzene, hexane, acetonitrile and mixtures thereof.
Preferably the reduction is performed at temperatures from about −30 to 100° C., preferably from about −20 to 50° C., even more preferably from about −10 to 25° C.
The aglycon of the formula V may be isolated and purified or may be used in the synthesis of the final product of the formula I without further purification.
Starting from the aglycon of the formula V the product of the formula I may be obtained using the methods as described hereinbefore, preferably using the methods depicted and described in Scheme 2a.




In the reactions described hereinbefore, any reactive group present such as ethynyl, hydroxy, amino, alkylamino or imino groups may be protected during the reaction by conventional protecting groups which are cleaved again after the reaction.
For example, a protecting group for a hydroxy group may be a trimethylsilyl, acetyl, trityl, benzyl or tetrahydropyranyl group.
Protecting groups for an amino, alkylamino or imino group may be, for example, a formyl, acetyl, trifluoroacetyl, ethoxycarbonyl, tert.butoxycarbonyl, benzyloxycarbonyl, benzyl, methoxybenzyl or 2,4-dimethoxybenzyl group.
Moreover, the compounds and intermediates obtained may be resolved into their enantiomers and/or diastereomers, as mentioned hereinbefore. Thus, for example, cis/trans mixtures may be resolved into their cis and trans isomers, and compounds with at least one optically active carbon atom may be separated into their enantiomers.
Thus, for example, the cis/trans mixtures may be resolved by chromatography into the cis and trans isomers thereof, the compounds and intermediates obtained which occur as racemates may be separated by methods known per se (cf. Allinger N. L. and Eliel E. L. in “Topics in Stereochemistry”, Vol. 6, Wiley Interscience, 1971) into their optical antipodes and compounds or intermediates with at least 2 asymmetric carbon atoms may be resolved into their diastereomers on the basis of their physical-chemical differences using methods known per se, e.g. by chromatography and/or fractional crystallisation, and, if these compounds are obtained in racemic form, they may subsequently be resolved into the enantiomers as mentioned above.
The enantiomers are preferably separated by column separation on chiral phases or by recrystallisation from an optically active solvent or by reacting with an optically active substance which forms salts or derivatives such as e.g. esters or amides with the racemic compound, particularly acids and the activated derivatives or alcohols thereof, and separating the diastereomeric mixture of salts or derivatives thus obtained, e.g. on the basis of their differences in solubility, whilst the free antipodes may be released from the pure diastereomeric salts or derivatives by the action of suitable agents. Optically active acids in common use are e.g. the D- and L-forms of tartaric acid or dibenzoyltartaric acid, di-o-tolyltartaric acid, malic acid, mandelic acid, camphorsulphonic acid, glutamic acid, aspartic acid or quinic acid. An optically active alcohol may be for example (+) or (−)-menthol and an optically active acyl group in amides, for example, may be a (+)- or (−)-menthyloxycarbonyl.
Furthermore, the compounds and intermediates of the present invention may be converted into the salts thereof, particularly for pharmaceutical use into the physiologically acceptable salts with inorganic or organic acids. Acids which may be used for this purpose include for example hydrochloric acid, hydrobromic acid, sulphuric acid, methanesulphonic acid, phosphoric acid, fumaric acid, succinic acid, lactic acid, citric acid, tartaric acid or maleic acid.
The compounds according to the invention are advantageously also obtainable using the methods described in the examples that follow, which may also be combined for this purpose with methods known to the skilled man from the literature, for example, particularly the methods described in WO 98/31697, WO 01/27128, WO 02/083066, WO 03/099836 and WO 2004/063209.
In the foregoing and following text, H atoms of hydroxyl groups are not explicitly shown in every case in structural formulae. The Examples that follow are intended to illustrate the present invention without restricting it. In case the pressure is indicated in the unit “Torr”, the corresponding values can be converted into Si units by using 1 torr=133.322 Pa. The terms “room temperature” or “ambient temperature” denote a temperature of about 20° C.
Ac acetyl,
Bu butyl,
Et ethyl,
EtOAc ethylacetate,
i-Pr iso-propyl,
Me methyl,
MeOH methanol,
MTBE methyl-tertbutylether,
THF tetrahydrofuran.
EXPERIMENTAL PROCEDURES
Example I




(5-bromo-2-chloro-phenyl)-(4-methoxy-phenyl)-methanone
38.3 ml oxalyl chloride and 0.8 ml of dimethylformamide are added to a mixture of 100 g of 5-bromo-2-chloro-benzoic acid in 500 mL dichloromethane. The reaction mixture is stirred for 14 h, then filtered and separated from all volatile constituents in a rotary evaporator. The residue is dissolved in 150 ml dichloromethane, the resulting solution is cooled to −5° C., and 46.5 g of anisole are added. Then 51.5 g of aluminum trichloride are added batchwise so that the temperature does not exceed 5° C. The solution is stirred for another 1 h at 1 to 5° C. and then poured onto crushed ice. The organic phase is separated, and the aqueous phase is extracted three times with dichloromethane. The combined organic phases are washed with aqueous 1 M hydrochloric acid, twice with 1 M sodium hydroxide solution, and with brine. The organic phase is dried, the solvent is removed in vacuo, and the residue is recrystallized from ethanol.
Yield: 86.3 g (64% of theory)
Mass spectrum (ESI+): m/z=325/327/329 (Br+Cl) [M+H]+
The following compounds may be obtained analogously to Example I:
(1) (5-bromo-2-chloro-phenyl)-(4-(R)-tetrahydrofuran-3-yloxy-phenyl)-methanone
The reaction is carried out according to the procedure described above except for 2 equivalents of aluminum trichloride are used. The reaction mixture is stirred at room temperature after the addition of aluminum trichloride.




Mass spectrum (ESI+): m/z=382/384/386 (Br+Cl) [M+H]+
(2) (5-bromo-2-chloro-phenyl)-(4-(S)-tetrahydrofuran-3-yloxy-phenyl)-methanone
The reaction is carried out according to the procedure described above except for 2 equivalents of aluminum trichloride are used. The reaction mixture is stirred at room temperature after the addition of aluminum trichloride.




Example II




(5-bromo-2-chloro-phenyl)-(4-fluoro-phenyl)-methanone
Variant A:
8.7 mL oxalyl chloride and 0.3 mL of dimethylformamide are added to a mixture of 24 g of 5-bromo-2-chloro-benzoic acid in 150 mL dichloromethane. The reaction mixture is stirred for 14 h, then filtered and separated from all volatile constituents in a rotary evaporator. The residue is dissolved in 105 mL fluorobenzene and heated to 85° C. Then 13.3 g of aluminum trichloride are added batchwise and the resultant mixture is stirred for 16 h at 85° C. After cooling to ambient temperature, the reaction mixture is poured onto a mixture of 300 g crushed ice and 100 mL concentrated hydrochloric acid. The resultant mixture is extracted two times with ethyl acetate. The combined organic extracts are washed with aqueous 1 M sodium hydroxide solution, aqueous 1 M hydrochloric acid and brine. After drying over magnesium sulfate the solvent is removed in vacuo. The solidified residue is washed with petrol ether and dried in vacuo.
Yield: 25.0 g (80% of theory)
Mass spectrum (ESI+): m/z=313/315/317 (Br+Cl) [M+H]+
Variant B:
To a solution of 9.42 g 5-bromo-2-chloro-benzoic acid in 40 mL of fluorobenzene and 0.1 mL of N,N-dimethylformamide is added 4 mL of oxalyl chloride at 0 to 10° C. The solution is stirred at about 20° C. for 2 hours. The excess amount of oxalyl chloride is evaporated. The residue is diluted in 38 mL of fluorobenzene and 5.87 g of aluminum chloride is added at 0° C. in five portions. The solution is stirred at 80° C. for 5 hours and quenched with 60 mL of water at 0 to 25° C. The product is extracted in 50 mL of isopropylacetate and washed with two times of 40 mL 3 weight-% brine. The solvent is removed upon evaporation and the product is crystallized from heptane and water.
Yield: 11.94 g (92.4% of theory)
Mass spectrum (ESI+): m/z=314/316 (Cl) [M+H]+
Example III




(2-Chloro-5-iodo-phenyl)-(4-fluoro-phenyl)-methanone
To a solution of 48.94 g 2-chloro-5-iodo-benzoic acid in 180 mL of fluorobenzene and 0.3 mL of N,N-dimethylformamide is added 16.2 mL of oxalyl chloride at 0 to 10° C. The solution is stirred at about 20° C. for 2 hours. The excess amount of oxalyl chloride is evaporated. The residue is diluted in 166 mL of fluorobenzene and 25.93 g of aluminum chloride is added at 0° C. in five portions. The solution is stirred at 75° C. for 1.5 hours and quenched with 300 mL of water at 0 to 25° C. The product is extracted in 300 mL of isopropylacetate and washed with two times of 200 mL brine (3 weight-%). The residue water and solvent is removed upon evaporation.
Yield: 60.56 g (95% of theory)
Mass spectrum (ESI+): m/z=361/363 (Cl)[M+H]+
Example IV




(5-bromo-2-chloro-phenyl)-(4-(S)-tetrahydrofuran-3-yloxy-phenyl)-methanone
Variant A:
To a solution of 8.1 g (S)-3-hydroxy-tetrahydrofuran in 200 ml dimethylformamide are added 10.3 g potassium tert-butoxide. The mixture is stirred at room temperature for 10 min and then 24.0 g (5-bromo-2-chloro-phenyl)-(4-fluoro-phenyl)-methanone are added so with cooling in a water bath that the solution temperature remained below 35° C. The reaction mixture is stirred for 14 h at room temperature and then diluted with 1000 mL water. The resultant mixture is extracted with ethyl acetate and the combined extracts are washed with water and brine. After drying over magnesium sulfate the solvent is removed and the residue is recrystallized from ethanol.
Yield: 22.5 g (77% of theory)
Mass spectrum (ESI+): m/z=382/384/386 (Br+Cl) [M+H]+
Variant B:
To a solution of 19.00 g (5-bromo-2-chloro-phenyl)-(4-fluoro-phenyl)-methanone in 60 mL of tetrahydrofuran and 5.87 g of (S)-3-hydroxytetrahydrofuran is added 9.60 g of potassium tert-butoxide in 90 mL of tetrahydrofuran at 0 to 5° C. The solution is stirred at 10° C. for 0.5 hour. The reaction is quenched with 60 mL of water and 40 mL of methyl tert-butyl ether at 0 to 25° C. The product is washed with 80 mL of brine (3 weight-%). The solvent is removed upon evaporation and crystallized in 135 mL of 2:1 isopropylacetate/water.
Yield: 20.1 g (87% of theory)
Mass spectrum (ESI+): m/z=382/384 (Cl) [M+H]+
Example V




(2-Chloro-5-iodo-phenyl)-{4-[(S)-(tetrahydrofuran-3-yl)oxy]-phenyl}-methanone
To a solution of 60.56 g (2-chloro-5-iodo-phenyl)-(4-fluoro-phenyl)-methanone in 170 mL of tetrahydrofuran and 16.46 g of (S)-3-hydroxytetrahydrofuran is added 26 g of potassium tert-butoxide in 250 mL of tetrahydrofuran at 0 to 5° C. The solution is stirred at 10° C. for 0.5 hour. The reaction is quenched with 170 mL of water and 170 mL of methyl tert-butyl ether at 0 to 25° C. The product is washed with 170 mL of brine (3 weight-%). The solvent is removed upon evaporation and crystallized in 220 mL of iso-propylacetate.
Yield: 65.1 g (90% of theory)
Mass spectrum (ESI+): m/z=428/430 (Cl) [M+H]+
Example VI




4-bromo-2-bromomethyl-1-chloro-benzene
4.0 g N-bromosuccinimide are slowly added to a solution of 5.0 g of 4-bromo-1-chloro-2-hydroxymethyl-benzene and 5.9 g triphenylphosphine in 50 mL of tetrahydrofuran chilled to 5° C. After 1 h stirring at ambient temperature the precipitate is filtered off, and the solvent is eliminated in vacuo. The residue is purified by chromatography on silica gel (cyclohexane/ethyl acetate 50:1).
Yield: 4.9 g (76% of theory)
Mass spectrum (EI): m/z=282/284/286 (Br+Cl) [M]+
Example VII




4-bromo-1-chloro-2-(4-methoxy-benzyl)-benzene
A solution of 86.2 g (5-bromo-2-chloro-phenyl)-(4-methoxy-phenyl)-methanone and 101.5 mL triethylsilane in 75 mL dichloromethane and 150 mL acetonitrile is cooled to 10° C. 50.8 mL of boron trifluoride etherate are added so that the temperature does not exceed 20° C. The solution is stirred for 14 h at ambient temperature, before another 9 mL triethylsilane and 4.4 mL boron trifluoride etherate are added. The solution is stirred for a further 3 h at 45 to 50° C. and then cooled to ambient temperature. A solution of 28 g potassium hydroxide in 70 mL of water is added, and the resultant mixture is stirred for 2 h. Then the organic phase is separated, and the aqueous phase is extracted three times with diisopropylether. The combined organic phases are washed twice with 2 M potassium hydroxide solution and once with brine and then dried over sodium sulfate. After the solvent is removed, the residue is washed with ethanol and dried at 60° C.
Yield: 50.0 g (61% of theory)
Mass spectrum (ESI+): m/z=310/312/314 (Br+Cl) [M+H]+
The following compounds may be obtained analogously to Example VII:
(1) 4-bromo-1-chloro-2-(4-cyclopentyloxy-benzyl)-benzene




(2) (S)4-bromo-1-chloro-2-(4-tetrahydrofuran-3-yloxy-benzyl)-benzene




(3) (R)4-bromo-1-chloro-2-(4-tetrahydrofuran-3-yloxy-benzyl)-benzene




(4) 4-bromo-1-chloro-2-(4-tetrahydropyran-4-yloxy-benzyl)-benzene




(5) 4-bromo-1-chloro-2-(4-cyclohexyloxy-benzyl)-benzene




(6) 4-bromo-1-chloro-2-(4-cyclobutyloxy-benzyl)-benzene




Example VIII




4-(5-bromo-2-chloro-benzyl)-phenol
A solution of 14.8 g 4-bromo-1-chloro-2-(4-methoxy-benzyl)-benzene in 150 ml dichloromethane is cooled in the ice bath. Then 50 ml of a 1 M solution of boron tribromide in dichloromethane are added, and the solution is stirred for 2 h at ambient temperature. The solution is then cooled in the ice bath again, and saturated potassium carbonate solution is added dropwise. At ambient temperature the mixture is adjusted with aqueous 1 M hydrochloric acid to a pH of about 1, the organic phase is separated off and the aqueous phase is extracted another three times with ethyl acetate. The combined organic phases are dried over sodium sulphate, and the solvent is removed completely.
Yield: 13.9 g (98% of theory)
Mass spectrum (ESI−): m/z=295/297/299 (Br+Cl) [M−H]−
Example IX




4-Bromo-1-chloro-2-(4-cyclopentyloxy-benzyl)-benzene
To a mixture of 40.0 g 4-(5-bromo-2-chloro-benzyl)-phenol and 71.0 g cesium carbonate in 300 mL ethanol are added 23 mL iodocyclopentane. The mixture is stirred at 60° C. over night and then cooled to ambient temperature. The ethanol is evaporated, and water is added to the residue. The resulting mixture is extracted with ethyl acetate, the combined extracts are dried over sodium sulfate, and the solvent is removed. The residue is filtered through silica gel (cyclohexane/ethyl acetate 100:1→10:1).
Yield: 34.4 g (70% of theory)
Mass spectrum (ESI+): m/z=364/366/368 (Br+Cl) [M]+
The following compounds may be obtained analogously to Example IX:
(1) (S)-4-bromo-1-chloro-2-(4-tetrahydrofuran-3-yloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=366/368/370 (Br+Cl) [M+H]+
(2) (R)-4-bromo-1-chloro-2-(4-tetrahydrofuran-3-yloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=366/368/370 (Br+Cl) [M]+
(3) 4-bromo-1-chloro-2-(4-tetrahydropyran-4-yloxy-benzyl)-benzene




(4) 4-bromo-1-chloro-2-(4-cyclohexyloxy-benzyl)-benzene




(5) 4-bromo-1-chloro-2-(4-cyclobutyloxy-benzyl)-benzene




Example X




(S)4-bromo-1-chloro-2-(4-tetrahydrofuran-3-yloxy-benzyl)-benzene
Variant A:
To a suspension of 250 g (5-bromo-2-chloro-phenyl)-{4-[(S)-(tetrahydro-furan-3-yl)oxy]-phenyl}-methanone in 1.33 L of acetonitrile and 314 mL of triethylsilane is added 93 mL of boron trifluoride diethyl etherate at 20° C. The solution is stirred at 20° C. for 16 hours. The mixture is filtered and the filtrate is quenched with 1.5 L of 1.5 M sodium hydroxide solution at 0 to 20° C. The solvent is removed upon evaporation and the residue is diluted with 1.3 L of methyl tert-butyl ether. The product is washed with 1.2 L of 0.1 M NaOH followed by 1 L of water. The solvent is removed upon evaporation and most of the triethylsilanol is removed upon the distillation of toluene.
Yield: 218 g (90% of theory)
Mass spectrum (ESI+): m/z=368/370 (Cl) [M+H]+
Variant B:
To a suspension of 50.00 g (5-bromo-2-chloro-phenyl)-{4-[(S)-(tetrahydro-furan-3-yl)oxy]-phenyl}-methanone in 260 mL of acetonitrile and 34.68 g of dimethylethylsilane is added 20.45 g of boron trifluoride diethyl etherate at 20° C. The solution is stirred at 20° C. for 16 hours. The mixture is filtered and the filtrate is quenched with 290 mL of 1.5 M sodium hydroxide solution at 0 to 20° C. The solvent is removed upon evaporation and the residue is diluted with 260 mL of methyl tert-butyl ether. The product is washed with 240 mL of 0.1 M NaOH followed by 200 mL of water. The solvent is removed upon evaporation and most of the dimethylethylsilanol is removed upon the distillation of heptane.
Yield: 45.76 g (95% of theory)
Mass spectrum (ESI+): m/z=368/370 (Cl) [M+H]+
Variant C:
To a suspension of 1.91 g (5-bromo-2-chloro-phenyl)-{4-[(S)-(tetrahydro-furan-3-yl)oxy]-phenyl}-methanone and 0.38 g of sodium borohydride in 10 mL of methylene chloride (or fluorobenzene alternatively) is added 5.92 g of trifluoroacetic acid at 0° C. The solution is stirred at 20° C. for 16 hours and quenched with 20 mL of water and 20 mL of MTBE at 0 to 20° C. The product is washed with 20 mL of water. The solvent is removed upon evaporation.
Yield: 1.6 to 1.75 g (87 to 95% of theory)
Variant D:
To a suspension of 1.91 g (5-bromo-2-chloro-phenyl)-{4-[(S)-(tetrahydro-furan-3-yl)oxy]-phenyl}-methanone and 0.8 g of sodium borohydride in 10 mL of isopropyl acetate is added 11.4 g of trifluoroacetic acid at 0° C. The solution is stirred at 20° C. for 16 hours and quenched with 20 mL of water and 20 mL of MTBE at 0 to 20° C. The product is washed with 20 mL of water. The solvent is removed upon evaporation.
Yield: 1.6 ̃1.75 g (87 ̃95% of theory)
Variant E:
To a solution of 0.19 g (5-bromo-2-chloro-phenyl){4-[(S)-(tetrahydro-furan-3-yl)oxy]-phenyl}-methanone in 5 mL of tetrahydrofuran is added 0.04 g of sodium borohydride at 20° C. The solution is stirred at 20° C. for 16 hours and the solvent is exchanged to 5 mL of methylene chloride. To the slurry is added 0.35 mL of 1 M boron trichloride methylene chloride solution, 0.02 mL of water and 0.24 mL of trifluoroacetic acid at 0° C., respectively. The mixture is stirred at ambient temperature for 4 hours and quenched with 10 mL of water and 10 mL of MTBE at 0 to 20° C. The product is washed with 10 mL of water. The solvent is removed upon evaporation.
Yield: 0.18 g (97% of theory)
Example XI




(S)-4-iodo-1-chloro-2-(4-tetrahydrofuran-3-yloxy-benzyl)-benzene
Variant A:
To a suspension of 63.12 g (2-chloro-5-iodo-phenyl)-{4-[(S)-(tetrahydro-furan-3-yl)oxy]-phenyl}-methanone in 300 mL of acetonitrile and 40.14 g of dimethylethylsilane is added 23.66 g of boron trifluoride diethyl etherate at 10° C. The solution is stirred at 20° C. for 16 hours. The reaction is quenched with 350 mL of 1.5 M sodium hydroxide solution at 0 to 20° C. The product is diluted in 200 mL of ethyl acetate. The product is washed with 200 mL of water. The solvent is removed upon evaporation and crystallized in 1:2 acetonitrile/water.
Yield: 54.9 g (90% of theory)
Mass spectrum (ESI+): m/z=414/416 (Cl)[M+H]+
Variant B:
To a solution of 0.22 g (2-chloro-5-iodo-phenyl)-{4-[(S)-(tetrahydro-furan-3-yl)oxy]-phenyl}-methanone in 5 mL of tetrahydrofuran is added 0.04 g of sodium borohydride at 20° C. The solution is stirred at 20° C. for 16 hours and the solvent is exchanged to 5 mL of methylene chloride. To the slurry is added 0.35 mL of 1 M boron trichloride methylene chloride solution, 0.02 mL of water and 0.24 mL of trifluoroacetic acid at 0° C., respectively. The mixture is stirred at 20° C. for 4 hours and quenched with 10 mL of water and 10 mL of MTBE at 0 to 20° C. The product is washed with 10 mL of water. The solvent is removed upon evaporation and crystallized in 1:2 acetonitrile/water.
Yield: 0.18 g (86% of theory)
Mass spectrum (ESI+): m/z=414/416 (Cl)[M+H]+
Example XII




2,3,4,6-tetrakis-O-(trimethylsilyl)-D-glucopyranone
A solution of 20 g D-glucono-1,5-lactone and 98.5 ml N-methylmorpholine in 200 ml of tetrahydrofuran is cooled to −5° C. Then 85 ml trimethylsilylchloride are added dropwise so that the temperature does not exceed 5° C. The solution is then stirred for 1 h at ambient temperature, 5 h at 35° C. and again for 14 h at ambient temperature. After the addition of 300 ml of toluene the solution is cooled in an ice bath, and 500 ml of water are added so that the temperature does not exceed 10° C. The organic phase is then separated and washed with aqueous sodium dihydrogen phosphate solution, water, and brine. The solvent is removed in vacuo, the residue is taken up in 250 ml of toluene, and the solvent is again removed completely.
Yield: 52.5 g (approx. 90% pure)
Mass spectrum (ESI+): m/z=467 [M+H]+
Example XIII




1-Chloro-4-(1-methoxy-D-glucopyranos-1-yl)-2-(4-(R)-tetrahydrofuran-3-yloxy-benzyl)-benzene
A solution of 5.40 g (R)-4-bromo-1-chloro-2-(4-tetrahydrofuran-3-yloxy-benzyl)-benzene in 85 mL dry diethylether is cooled to −78° C. under argon. 18.5 mL of a 1.7 M solution of tert-butyllithium in pentane are slowly added dropwise to the cooled solution, and then the solution is stirred for 45 min at −78° C. Then a −78° C. cold solution of 7.50 g (ca. 90% pure) of 2,3,4,6-tetrakis-O-(trimethylsilyl)-D-glucopyranone in 35 mL diethylether is added through a transfer needle. The resulting solution is stirred for 2 h at −78° C., and then a solution of 2.5 ml methanesulfonic acid in 65 mL of methanol is added. The cooling bath is removed, and the solution is stirred for 16 h at ambient temperature. The solution is then neutralized with solid sodium hydrogencarbonate, most of the solvent is removed, and aqueous sodium hydrogen carbonate solution is added to the residue. The resulting mixture is extracted with ethyl acetate, the combined extracts are dried over sodium sulfate, and the solvent is removed to furnish the crude product that is submitted to reduction without further purification.
Yield: 6.95 g (crude product)
Mass spectrum (ESI+): m/z=503/505 (Cl) [M+Na]+
The following compounds may be obtained analogously to Example XIII:
(1) 1-Chloro-4-(1-methoxy-D-glucopyranos-1-yl)-2-(4-(S)-tetrahydrofuran-3-yloxy-benzyl)-benzene




(2) 1-Chloro-4-(1-methoxy-D-glucopyranos-1-yl)-2-(4-cyclopentyloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=501/503 (Cl) [M+Na]+
Example XIV




1-Chloro-4-(2,3,4,6-tetra-O-acteyl-D-glucopyranos-1-yl)-2-(4-(R)-tetrahydrofuran-3-yloxy-benzyl)-benzene
A solution of 6.95 g 1-chloro-4-(1-methoxy-D-glucopyranos-1-yl)-2-(4-(R)-tetrahydro-furanyloxy-benzyl)-benzene and 4.7 mL triethylsilane in 40 ml dichloromethane and 80 ml acetonitrile is cooled to −10° C. Then 1.25 mL boron trifluoride etherate are added dropwise so that the solution temperature remained below 0° C. The solution is stirred for 3 h in an ice bath. Aqueous sodium hydrogen carbonate solution is added, and the resulting mixture is extracted with ethyl acetate. The organic phase is dried over sodium sulfate, the solvent is removed, and the residue is taken up in 80 mL dichloromethane. Then 8.5 mL of pyridine, 7.8 mL of acetic anhydride and 100 mg of 4-dimethylaminopyridine are added. The solution is stirred for 1 h at ambient temperature and then diluted with water. The mixture is extracted with dichloromethane, the organic phase is washed with 1 M hydrochloric acid and dried over sodium sulfate. After the solvent is removed the residue is recrystallized from ethanol to furnish the product as white crystals.
Yield: 2.20 g (25% of theory)
Mass spectrum (ESI+): m/z=619/621 (Cl) [M+H]+
The following compounds may be obtained analogously to Example XIV:
(1) 1-Chloro-4-(2,3,4,6-tetra-O-acteyl-D-glucopyranos-1-yl)-2-(4-(S)-tetrahydrofuran-3-yloxy-benzyl)-benzene




(2) 1-Chloro-4-(2,3,4,6-tetra-O-acteyl-D-glucopyranos-1-yl)-2-(4-cyclopentyloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=640/642 (Cl) [M+Na]+
Example XV




1-Chloro-4-(2,3,4,6-tetra-O-benzyl-D-glucopyranos-1-yl)-2-(4-(S)-tetrahydrofuran-3-yloxy-benzyl)-benzene
A solution of 0.37 g 1-chloro-4-(1-methoxy-2,3,4,6-tetra-O-benzyl-D-glucopyranos-1-yl)-2-(4-(S)-tetrahydrofuran-3-yloxy-benzyl)-benzene and 0.21 mL triethylsilane in 2.5 ml dichloromethane and 7.5 ml acetonitrile is cooled to −20° C. Then 0.13 mL boron trifluoride etherate are added dropwise over 1 min. The resulting mixture is allowed to warm to −10° C. over 1 h. Aqueous sodium hydrogen carbonate solution is added, and the resulting mixture is extracted with ethyl acetate. The organic phase is washed with brine, dried over sodium sulfate, and concentrated under vacuum. The resulting residue was purified by column chromatography to give a mixture of alpha and beta isomers (alpha:beta ratio approximately 1:3) as a thick oil in quantitative yield.
Yield: 0.36 g (100% of theory)
Mass spectrum (ESI+): m/z=833/835 (Cl) [M+Na]+
Example XVI




1-Chloro-4-(2,3,4,6-tetra-O-allyl-D-glucopyranos-1-yl)-2-(4-(S)-tetrahydrofuran-3-yloxy-benzyl)-benzene
A solution of 0.37 g 1-chloro-4-(l-methoxy-2,3,4,6-tetra-O-allyl-D-glucopyranos-1-yl)-2-(4-(S)-tetrahydrofuranyloxy-benzyl)-benzene and 0.28 mL triethylsilane in 2.5 ml dichloromethane and 7.5 ml acetonitrile is cooled to −20° C. Then 0.16 mL boron trifluoride etherate are added dropwise over 1 min. The resulting mixture is allowed to warm to −10° C. over 1 h. Aqueous sodium hydrogen carbonate solution is added, and the resulting mixture is extracted with ethyl acetate. The organic phase is washed with brine, dried over sodium sulfate, and concentrated under vacuum. The resulting residue was purified by column chromatography to give a mixture of alpha and beta isomers (alpha:beta ratio approximately 1:9) as a thick oil.
Yield: 0.30 g (85% of theory)
Mass spectrum (ESI+): m/z=633/635 (Cl) [M+Na]+
Example XVII




1-Chloro-4-(β-D-glucopyranos-1-yl)-2-(4-(R)-tetrahydrofuran-3-yloxy-benzyl)-benzene
To a solution of 2.20 1-chloro-4-(2,3,4,6-tetra-O-acetyl-D-glucopyranos-1-yl)-2-(4-(R)-tetrahydrofuran-3-yloxy-benzyl)-benzene in 30 mL of methanol is added 4 mL of 4 M aqueous potassium hydroxide solution. The solution is stirred at ambient temperature for 1 h and then neutralized with 4 M hydrochloric acid. The methanol is evaporated, and the residue is diluted with brine and extracted with ethyl acetate. The combined organic extracts are dried over sodium sulfate, and the solvent is removed. The residue is chromatographed on silica gel (dichloromethane/methanol 1:0→4:1).
Yield: 1.45 g (90% of theory)
Mass spectrum (ESI+): m/z=451/453 (Cl) [M+H]+
The following compounds may be obtained analogously to Example XVII:
(1) 1-Chloro-4-(β-D-glucopyranos-1-yl)-2-(4-(S)-tetrahydrofuran-3-yloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=451/453 (Cl) [M+H]+
(2)1-Chloro-4-(β-D-glucopyranos-1-yl)-2-(4-cyclopentyloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=466/468 (Cl) [M+NH4]+
(3) 1-Chloro-4-(β-D-glucopyranos-1-yl)-2-(4-tetrahydropyran-4-yloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=487/489 (Cl) [M+Na]+
(4) 1-Chloro-4-(β-D-glucopyranos-1-yl)-2-(4-cyclohexyloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=480/482 (Cl) [M+NH4]+
(5) 1-Chloro-4-(β-D-glucopyranos-1-yl)-2-(4-cyclobutyloxy-benzyl)-benzene




Mass spectrum (ESI+): m/z=452/454 (Cl) [M+NH4]+
Example XVIII




1-Chloro-4-(β-D-glucopyranos-1-yl)-2-(4-(S)-tetrahydrofuran-3-yloxy-benzyl)-benzene
Variant A:
Step i)
To a solution of 5.5 mL 2.0 M BuMgCl in THF in 30 mL of tetrahydrofuran is added 12 mL of 2.5 M BuLi in hexane at −15 to −5° C. and stirred at −10° C. for 20 minutes. 10.00 g of (S)-3-[4-(5-bromo-2-chloro-benzyl)-phenoxy]-tetrahydrofuran in 10 mL of THF is added at −23 to −20° C. and stirred at −22° C. for 20 min. 20.32 g of 2,3,4,6-tetrakis-O-(trimethylsilyl)-D-glucopyranone in 7 mL of THF is added at −20 to −18° C. The reaction is then stirred at −20° C. for 1 hour and warmed to −12° C. in another hour. 60 mL of 25 weight-% aqueous NH4Cl solution is added to quench the reaction. 40 mL of MTBE is added and the organic layer is separated. The aqueous layer is extracted with 30 mL of EtOAc. The combined organic phases are dried over MgSO4 and concentrated.
Step ii)
The residue of step i) is dissolved in 100 mL of MeOH and 0.52 g of MeSO3H and stirred at 43° C. for 4 hours. The reaction is then cooled to 5° C. and quenched with 20 mL of 10 weight-% NaHCO3 aqueous solution. MeOH is distilled under reduced pressure and 25 mL of water and 25 mL of EtOAc are added. The organic layer is separated, and the aqueous phase is extracted with 20 mL of EtOAc. The combined organic phases are dried and concentrated to dryness.
Step iii)
The residue of step ii) was dissolved in 63 mL of MeCN and 43 mL of CH2Cl2 and cooled to −20° C. 7.59 g of triethylsilane is added, followed by addition of 6.95 g of boron trifluoride etherate. The reaction is warmed up gradually from −20 to 10° C. over 2 h. 40 g of 10 weight-% NaHCO3 is added to quench the reaction. The organic solvents are removed under reduced pressure. 50 mL of isopropyl acetate and 12 mL of water are charged and the mixture is stirred at ambient temperature for overnight. The product is filtered and dried.
Yield: 13.5 g (55% of theory)
Mass spectrum (ESI+): m/z=451/453 (Cl) [M+H]+
Variant B:
Instead of BuMgCl in step i) of variant A i-PrMgCl is used. The steps ii) and iii) are as in variant A.
Variant C:
Instead of BuMgCl in step i) of variant A i-PrMgCl/LiCl is used. The steps ii) and iii) are as in variant A.
Variant D:
Step i)
To a solution of 2.90 g (S)-3-[4-(5-bromo-2-chloro-benzyl)-phenoxy]-tetrahydrofuran in 4 mL of THF at 0 to 20° C. (or alternatively at 20° C.), is slowly charged 8.4 mL of 1.0 M i-PrMgCl/LiCl in THF. The reaction is stirred at 20° C. for 16 hours and cooled to −23° C. 4.3 g of 2,3,4,6-tetrakis-O-(trimethylsilyl)-D-glucopyranone in 2 mL of THF is added dropwise. The reaction is then stirred at −20° C. for 2 h. Aqueous NH4Cl solution (25 weight-%, 12 mL) is added to quench the reaction. MTBE (8 mL) is added and the organic layer is separated. The aqueous layer is extracted with EtOAc (30 mL). The combined organic phases are dried over MgSO4 and concentrated.
Step ii)
The residue of step i) is dissolved in MeOH (20 mL) and MeSO3H (260 mg, 2.8 mmol) and stirred at 43° C. for 3 h. The reaction is then cooled to 5° C. and quenched with 10 weight-% NaHCO3 aqueous solution (12 mL). MeOH is distilled under reduced pressure and water (4 mL) and EtOAc (30 mL) are added. The organic layer is separated, and the aqueous phase is extracted with EtOAc (20 ml). The combined organic phases are dried and concentrated to dryness.
Step iii)
The residue of step ii) is dissolved in MeCN (17 mL) and CH2Cl2 (11 mL) and cooled to −20° C. Triethylsilane (2.08 g, 17.9 mmol) is added, followed by addition of boron trifluoride etherate (1.9 g, 13.4 mmol). The reaction is warmed up gradually from −20 to 10° C. over 2 h. 10% NaHCO3 (25 mL) is added to quench the reaction. Organic solvents are removed under reduced pressure. Isopropyl acetate (15 mL) and water (5 ml) are charged and the mixture is stirred at ambient temperature for overnight. The product is filtered and dried.
Yield: 0.91 g (27% of theory)
Mass spectrum (ESI+): m/z=451/453 (Cl) [M+H]+
Variant E:
Step i)
To a solution of 2.90 g (S)-3-[4-(5-iodo-2-chloro-benzyl)-phenoxy]-tetrahydrofuran in 4 mL of THF at −23° C., is slowly charged 8.4 mL of 1.0 M i-PrMgCl/LiCl in THF. The reaction is stirred at −22° C. for 20 minutes. 4.3 g of 2,3,4,6-tetrakis-O-(trimethylsilyl)-D-glucopyranone in 2 mL of THF is added dropwise. The reaction is then stirred at −20° C. for 2 h. Aqueous NH4Cl solution (25 weight-%, 12 mL) is added to quench the reaction. MTBE (8 mL) is added and the organic layer is separated. The aqueous layer is extracted with EtOAc (30 mL). The combined organic phases are dried over MgSO4 and concentrated.
Step ii)
The residue of step i) is dissolved in MeOH (20 mL) and MeSO3H (260 mg, 2.8 mmol) and stirred at 43° C. for 3 h. The reaction is then cooled to 5° C. and quenched with 10 weight-% NaHCO3 aqueous solution (12 mL). MeOH is distilled under reduced pressure and water (4 mL) and EtOAc (30 mL) are added. The organic layer is separated, and the aqueous phase is extracted with EtOAc (20 ml). The combined organic phases are dried and concentrated to dryness.
Step iii)
The residue of step ii) is dissolved in MeCN (17 mL) and CH2Cl2 (11 mL) and cooled to −20° C. Triethylsilane (2.08 g, 17.9 mmol) is added, followed by addition of boron trifluoride etherate (1.9 g, 13.4 mmol). The reaction is warmed up gradually from −20 to 10° C. over 2 h. 25 ml aqueous 10 weight-% NaHCO3 are added to quench the reaction. Organic solvents are removed under reduced pressure. Isopropyl acetate (15 mL) and water (5 ml) are charged and the mixture is stirred at ambient temperature for overnight. The product is filtered and dried.
Yield: 2.2 g (65% of theory)
Mass spectrum (ESI+): m/z=451/453 (Cl) [M+H]+

## Claims

1. Process for preparing the compounds of general formula III,



wherein
R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and
R2 independently of one another denote hydrogen, (C1-18-alkyl)carbonyl, (C1-18-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl, aryl-C1-3-alkyl, allyl,
RaRbRcSi, CRaRbORc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SiRaRb, CRaRb or CRaORb—CRaORb; and
R′ denotes hydrogen, C1-6-alkyl, (C1-4-alkyl)carbonyl, (C1-4-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl;
Ra, Rb, Rc independently of one another denote C1-4-alkyl, aryl or aryl-C1-3-alkyl, while the alkyl groups may be mono- or polysubstituted by halogen;
L1 independently of one another are selected from among fluorine, chlorine, bromine, C1-3-alkyl, C1-4-alkoxy and nitro;
while by the aryl groups mentioned in the definition of the above groups are meant phenyl or naphthyl groups, which may be mono- or polysubstituted with L1;
said method comprised of the step of adding an organometallic compound of the formula VI




wherein R1 is defined as hereinbefore and M denotes Li or MgHal, wherein Hal denotes Cl, Br or I;
or a derivative thereof obtained by transmetallation;
which compound of the formula VI may be obtained by halogen-metal exchange or by the insertion of a metal in the carbon-halogen bond of a halogen-benzylbenzene compound of general formula V




wherein R1 is defined as hereinbefore and X denotes Br or I;
and optionally subsequent transmetallation, to a gluconolactone of general formula IV




wherein R2 is as hereinbefore defined,
and reacting the adduct obtained with water or an alcohol R′—OH, where R′ denotes C1-6-alkyl, in the presence of an acid and optionally the product obtained in the reaction with water wherein R′ denotes H is converted in a subsequent reaction with an acylating agent into the product of formula III wherein R′ denotes (C1-4-alkyl)carbonyl, (C1-4-alkyl)oxycarbonyl, arylcarbonyl, or aryl-(C1-3-alkyl)-carbonyl, wherein the term aryl is defined as hereinbefore.

2. Process for preparing a compound of general formula II,



wherein
R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and
R2 independently of one another denote hydrogen, (C1-18-alkyl)carbonyl, (C1-18-alkyl)oxycarbonyl, arylcarbonyl, aryl-(C1-3-alkyl)-carbonyl, aryl-C1-3-alkyl, allyl, RaRbRcSi, CRaRbORc, wherein two adjacent groups R2 may be linked with each other to form a bridging group SiRaRb, CRaRb or CRaORb—CRaORb;
RaRb, Rc independently of one another denote C1-4-alkyl, aryl or aryl-C1-3-alkyl, while the alkyl groups may be mono- or polysubstituted by halogen;
wherein an aglycon of the formula V




wherein
R1 denotes cyclobutyl, cyclopentyl, cyclohexyl, R-tetrahydrofuran-3-yl, S-tetrahydrofuran-3-yl or tetrahydropyran-4-yl; and
X denotes a bromine atom or a iodine atom;
is obtained by a method comprised of the steps of reacting a benzoyl chloride derivative of the formula XII




wherein X is defined as above; or a derivative thereof such as a benzoyl anhydride, an ester or a benzonitrile;
with a halobenzene of the formula XXVII




wherein Z5 denotes a fluorine, chlorine or iodine atom;
in the presence of a catalyst to obtain an intermediate compound of the formula XXVI




wherein X and Z5 are defined as hereinbefore; and
reacting the intermediate compound of the formula XXVI with R1—OH, wherein R1 is defined as hereinbefore, or an anion thereof, in the presence of a base to yield a benzophenone derivative of the formula VII




wherein X and R1 are defined as hereinbefore; and
the benzophenone derivative of the formula VII is reacted with a reducing agent in the presence of a Lewis acid to furnish the compound of the formula V as defined above,
and said compound of general formula V is transformed into an organometallic compound of the formula VI




wherein R1 is defined as hereinbefore and M denotes Li or MgHal, wherein Hal denotes Cl, Br or I;
by an halogen-metal exchange or by the insertion of a metal in the carbon-halogen bond of the compound of general formula V, and optionally subsequent transmetallation; and
said organometallic compound of the formula VI is reacted with a gluconolactone of general formula IV




wherein R2 is as hereinbefore defined, in accordance with the process according to claim 1 to obtain an intermediate of the formula III,




wherein R2, R′ and R1 are defined as in claim 1, and
reacting said intermediate of the formula III with a reducing agent to obtain the compound of the formula II.

3. Process according to claim 2 wherein in formula lithe substituent R2 denotes hydrogen, and in the formulae IV the substituent R2 denotes a protecting group as defined in claim 1, and in the formula III the substituent R2 has the same meaning as in formula IV or denotes hydrogen.

4. Process according to claim 1, in which R1 denotes R-tetrahydrofuran-3-yl or S-tetrahydrofuran-3-yl.

5. Process according to claim 2, in which R1 denotes R-tetrahydrofuran-3-yl or S-tetrahydrofuran-3-yl.

6. Process according to claim 3, in which R1 denotes R-tetrahydrofuran-3-yl or S-tetrahydrofuran-3-yl.

7. Process according to claim 2, wherein in formula lithe substituent R2 denotes hydrogen, and in the formulae IV the substituent R2 denotes trimethylsilyl, and in the formula III the substituent R2 has the same meaning as in formula IV or denotes hydrogen.

8. Process according to claim 2, wherein the group X denotes iodine.

9. Process according to claim 2, wherein the group R′ denotes hydrogen, methyl or ethyl.

10. Process according to claim 2, wherein the group Z5 denotes fluorine.

11. Process according to claim 2, wherein the compound of the formula V is transformed into the organometallic compound of the formula VI by a halogen-metal exchange with C3-4-alkylmagnesium chloride or bromide without or in the presence of lithium chloride whereby the halogen-metal exchange is carried out between −80° C. and 10° C.

12. Process according to claim 2, wherein the compound of the formula V is transformed into the organometallic compound of the formula VI by a halogen-metal exchange with isopropylmagnesium chloride in the presence of lithium chloride whereby the halogen-metal exchange is carried out between −80° C. and 10° C.

13. Process according to claim 2, wherein the intermediate of the formula III is reacted with a silane as a reducing agent in the presence of or without a Lewis acid to obtain the compound of the formula II.

14. Process according to claim 2, wherein the intermediate of the formula III is reacted with triethylsilane as a reducing agent in the presence of a Lewis acid to obtain the compound of the formula II.