Patent ID: 8445708

Claim:
A process for preparing compounds of the general formula (I) in which R 1 and R 2 are each independently hydroxyl, alkoxy, aryloxy, arylalkyloxy or alkoxyalkoxy, the latter four groups each being unsubstituted or substituted; R 3 is a heterocarbon group containing at least one heteroatom selected from O and N with at least one carbon-heteroatom multiple bond at the C-1 position, said group being bonded via the C-1 atom and being selected from COOR 6 , in which R 6 is hydrogen, alkyl, aryl, arylalkyl or trialkylsilyl, wherein the alkyl and the aryl may each be unsubstituted or substituted; nitrile; C(O)R 7 , in which R 7 is selected from hydrogen, halogen, O − , OM, in which M is an alkali metal or an equivalent of an alkaline earth metal, OCOR 12 , in which R 12 is unsubstituted or substituted branched lower alkyl having from 1 to 5 carbon atoms, or pivaloyl, OCOCF 3 , OSO 2 CH 3 or OSO 2 CF 3 ; or R 3 comprises a protecting or activating group customary for carboxylic acids, or is C(O)NR 4 R 5 , in which R 4 and R 5 are independently hydrogen, alkyl, aryl, arylalkyl, or trialkylsilyl, wherein the alkyl and the aryl may each be unsubstituted or substituted, or R 4 and R 5 together with the nitrogen form a five- to six-membered heterocyclic ring system which may optionally have from 1 to 3 additional heteroatoms; or salts thereof, wherein a compound of the general formula (II) in which R 3 is in each case independently as defined above under the formula (I); is reacted in an addition reaction with a compound of the formula (III) in which Y is halogen, metal, metal halide, metal alkoxide or metal carboxylate, R 1 and R 2 are each as defined above under the formula (I), to obtain a compound of the formula (IV) in which R 1 , R 2 and R 3 are each as defined above under the formula (I); the dotted line represents a single or double bond; R 5 is O or NR 8 in which R 8 is hydrogen or unsubstituted or substituted alkyl if the dotted line represents a double bond, or R 5 is OH or NR 8 R 9 in which R 8 and R 9 are each independently hydrogen, alkyl or aryl or alkylaryl, each being unsubstituted or substituted if the dotted line represents a single bond; and the compound of the formula (IV) is subjected to at least one reduction reaction to obtain the desired product of the formula (I), wherein substituted means substituted by one or more of the following groups selected from halogen, hydroxyl, cyano, C 1 -C 6 -alkoxy, nitro, amino, C 1 -C 6 -alkylamino, di-C 1 -C 6 -alkylamino, carboxyl, C 1 -C 6 -alkoxycarbonyl, aminocarbonyl, halomethyl, dihalomethyl, trihalomethyl, haloethyl, dihaloethyl, trihaloethyl, tetrahaloethyl, and pentahaloelhyl.