Patent ID: 6797834
Filing Date: 2004-09-28
Classification: C07J

Abstract:
A process for the preparation of a &Dgr;4,9-steroid of formula (II) where R17 is: (1) &boxH;O; (2) &agr;-R17-1:&bgr;-R17-2 where one of R17-1 and R17-2 is: (a) â€”OH, (b) â€”Oâ€”Si(R17-2a)3 where R17-2a are the same or different and are C1-C6 alkyl or phenyl, (c) â€”Oâ€”COâ€”R17-2b where R17-2b is: (i) C1-C6 alkyl, (ii) phenyl, (d) â€”Oâ€”R17-2b where R17-2b is as defined above, and the other of R17-1 and R17-2 is â€”H; which comprises (1) contacting a &Dgr;5(10),9(11)-steroid of formula (I) where R17 is as defined above, with a phosphorous containing acid selected from the group consisting of phosphoric acid, polyphosphoric acid, metapahosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, tetrametaphosphoric acid, hypophosphoric acid, orthophosphoric acid or an acid containing phosphorus which is generated in situ.