Patent ID: 8138344

Claim:
A process for the production of a compound of formula I: wherein R 1 is alkyl, alkenyl, alkynyl, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, benzyl, alkoxybenzyl or chlorobenzyl, R 2 is a compound of formula II or III: wherein R 3 is selected from H, alkyl, alkenyl, alkynyl, aryl, arylalkyl, hydroxyarylalkyl, hydroxyaryl, hydroxyalkyl, dihydroxyalkyl, hydroxyalkoxyalkyl, hydroxyalkylarylalkyl, dihydroxyalkylarylalkyl, alkoxyalkyl, alkylcarbonyloxyalkyl, aminoalkyl, alkylaminoalkyl, alkoxycarbonylaminoalkyl, alkylcarbonylaminoalkyl, arylsulfonamidoalkyl, allyl, dihydroxyalkylallyl, dioxolanylallyl, carbalkoxyalkyl and alkylsilyl; R 4 is H, methyl or together with R 3 forms C 2-6 alkylene; R 5 is R 6 O—CH 2 —, wherein R 6 is selected from H, alkyl, alkenyl, alkynyl, aryl, alkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, hydroxyalkylcarbonyl, aminoalkylcarbonyl, formyl, arylalkyl, hydroxyarylalkyl, hydroxyaryl, hydroxyalkyl, dihydroxyalkyl, hydroxyalkoxyalkyl, hydroxyalkylarylalkyl, dihydroxyalkylarylalkyl, alkoxyalkyl, alkylcarbonyloxyalkyl, aminoalkyl, alkylaminoalkyl, alkoxycarbonylaminoalkyl, alkylcarbonylaminoalkyl, arylsulfonamidoalkyl, allyl, dihydroxyalkylallyl, dioxolanylallyl and carbalkoxyalkyl; Y is selected from O, (H, OH), and (H, OR 9 ), wherein R 9 is selected from C 1-4 alkyl, alkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, hydroxyalkylcarbonyl, aminoalkylcarbonyl, formyl or aryl; and, X is H, the process comprising A) treating a compound of formula IV: wherein R 1 , R 2 and Y are as defined above and wherein R′ is a the residue of an arylthionocarbonate or arylthionocarbamate which arylthionocarbonate or arylthionocarbamate is bound to the C-atom in position 32 of the ring structure via the —O— group, and wherein reactive groups are in unprotected or protected form, with tris(trimethylsilyl)-silan and α,α′-azo-isobutyronitril in organic solvent; B) optionally splitting off protective groups, if present; C) isolating a compound of formula I wherein R 1 , R 2 and Y are as defined above; and D) optionally converting a compound of formula I wherein R 1 is alkyl into a compound of formula I wherein R 1 is as defined above but not alkyl.