Process for preparing to prepare 3α-7α (β) -di-hydroxy-6α (β) -alkyl-5β-cholanic acids of general formula (I) ** (See formula) ** where the bond represented by a dashed line in position 6 and 7 it indicates that the substituent may be in position α or β, chosen from the class consisting of: i) 3-α, 7-α-dihydroxy-6-α-alkyl-5β-cholanic acid of the formula general (IA) ** (See formula) ** ii) 3-α, 7-α-dihydroxy-6-β-alkyl-5β-cholanic acid of the general formula (IB) ** (See formula) ** iii ) 3-α, 7-β-dihydroxy-6-α-alkyl-5β-collanic acid of the general formula (IC) ** (See formula) ** where R is a linear or branched C1-C5 alkyl, and that It comprises the following steps a) esterify 3α-hydroxy-7-keto-5β-cholanic acid (II) ** (See formula) ** in methanol and in an acidic medium, to obtain 3α-hydroxy-7-keto-5β- methyl (III) colanate, ** (See formula) ** b) silyl 3α-hydroxy-7-keto-5β-methyl (III) colanate with trimethylchlorosilane to obtain the c corresponding 3-α-trimethylsiloxy-7-keto-5β-colanate (IV), ** (See formula) ** c) silylate the methyl 3-α-trimethylsiloxy-7-keto-5β-colanate (IV) obtained in step (b) with trimethylchloro-silane in the presence of a strong base to obtain 3α-, 7α-di-trimethylsiloxy-6-en-5β-methyl colanate (V), ** (See formula) ** d) do reacting the 3α-, 7α-di-trimethylsiloxy-6-en-5β-methyl colanate (V) with the aldehyde R-CHO, in which R has the meanings indicated above, and with a Lewis acid, to obtain 3α- hydroxy-6-alkylidene-7-keto-5β-methyl colanate (VI), ** (See formula) ** e) hydrolyze 3α-hydroxy-6-alkylidene-7-keto-5β-methyl colanate to 3α acid -hydroxy-6-alkylidene-7-keto-5β-cholanic (VII), ** (See formula) ** f) hydrogenate 3α-hydroxy-6-alkylidene-7-keto-5β-cholanic acid in an alkaline medium with Pd / C to 3α-hydroxy-6β-alkyl-7-keto-5β-collanic acid ** (See formula) ** g) optional heat treatment of intermediate (VIII) in an alkaline medium In order to obtain the corresponding 3α-hydroxy-6α-alkyl-7-keto-5β-collanic acid (IX) ** (See formula) ** h) reduce the ketone group in position (7) of intermediate (VIII) or ( IX) to a 7-hydroxyl group, according to one of the following alternative operating conditions: h '') reduce the compound 3α-hydroxy-6α-alkyl-7-keto-5β-cholanic acid (IX) with metal hydride to 3α acid -, 7α-di-hydroxy-6α-alkyl-5β-cholanic (IA), h '' '') reduce the compound 3α-hydroxy-6α-alkyl-7-keto-5β-cholanic (IX) in the presence of sodium and alcohol, to obtain 3α-, 7β-di-hydroxy-6α-alkyl-5β-cholanic acid (IC), h '' '' '') reduce 3α-hydroxy-6β-alkyl-7-keto- 5β-cholanic (VIII) in the presence of a metal hydride to 3α-, 7α-di-hydroxy-6β-alkyl-5β-cholanic acid (IB).
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