Patent / 1972
Recovery of .alpha.-6-deoxytetracyclines from reaction mixtures
alpha.-6-Deoxytetracyclines were recovered from the reaction mixts. by treating the mixt. with aq. acid at 60-90.degree. for 15-90 min. This treatment destroyed the byproducts but did not interfere with the subsequent selective pptn. of the deoxytetracyclines. Terra-silica was added to crude 11a-chloro-6-deoxy-6-demethyl-6-methylene-5-hydroxytetracycline (I) in 70% aq. DMF and the resulting cake was washed with 50% aq. DMF. Concd. HCl was added, and the mixt. heated at 68-72.degree. for 30 min. After cooling 5-sulfosalicylic acid was added and the mixt. was stirred for 2 hr at 15.degree. to give the cryst. sulfosalicylate of I.