A Parr bottle is charged with 5% rhodium-on-carbon (2.88 gms., 50% wet material; 0.70 mM of rhodium), tri-(4-chlorophenyl)phosphine (0.76 gms., 2.1 mM) in 13 cc. methanol. The mixture is shaken for a half-hour at 62°C., under nitrogen atmosphere, at the end of which time a solution of 3.39 gms., 7.0 mM, of 6-deoxy-6-demethyl-6-methylene-5-hydroxytetracycline hydrochloride in 37 cc. of methanol, containing 7.0 mM of p-toluenesulfonic acid, is added. The bottle is then filled with hydrogen at 50 p.s.i. and shaken overnight at 75°C. for 18 hours. High pressure liquid chromatography of the reaction mixture indicates the presence of 80% α-6-deoxy-5-hydroxytetracycline and 1.5% 6β-epimer. α-6-deoxy-5-hydroxytetracycline may be isolated in 78% yield as the 5-sulfosalicyclic acid salt.
