Patent / 1985
Hovione Inter Ltd.
.alpha.-Deoxytetracyclines I (R = H, OH) were prepd. stereoselectively by reducing methylenetetracyclines II (R = H, OH; R1 = Br, Cl) and III on an aminopropylsilsesquioxane-supported Rh catalyst in the presence of a triarylphosphine. Thus, III (R = OH) was hydrogenated on RhCl3[N[(CH2)3SiO3/2]3]10 in the presence of PPh3 to give 87.4% doxycycline 99.6% pure.