Nippon Kayaku Kabushiki Kaisha

Kazuaki Sano

Hiroaki Ohno

Ryoichi Hasegawa

Yoshinori Saito

Hiroaki Nishiyama

Shin'ichi Umeda

A process for purifying 7-dimenthylamino-6-demethyl-6-deoxytetracycline represented by the following formula, ##STR1## which comprises dissolving 7-dimethylamino-6-demethyl-6-deoxytetracycline or its hydrochloride having a lower purity in a mixed solvent of an alcohol and water by using hydrochloric acid and then adjusting the pH of the solution to 3.5 to 4.5 to recrystallize the hydrochloride having a higher purity.

Process for purifying 7-dimethylamino-6-demethyl-6-deoxytetracycline

A process for producing 7-dimethylamino-6-demethyl-6-deoxytetracycline (minocycline) which comprises treating the reaction liquid containing minocycline and formaldehyde with hydroxylamine or urea, the reaction liquid being obtained after reductive methylation of 7-amino-6-demethyl-6-deoxytetracycline by using aldehyde, then subjecting the reaction liquid to an adsorption treatment with a nonionic adsorption resin (adsorbent), and subsequently eluting the intended product adsorbed to the adsorbent.

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Hoya, Japan

Kazuaki Sano