alpha.-6-Deoxytetracyclines were sepd. from their mixts. with by-products or decompn. products by adding 5,2-(HO3S)(HO)C6H3CO2H to the soln., crystg. and sepg. the .alpha.-6-deoxytetracycline salt and treating it with Et3N to obtain the free base, or by adding (PhCH2NHCH2)2 or (PhCH2N:CH)2 and Ca(OH)2 to the soln. to form an insol. complex with the desired tetracycline, sepg. the complex, and decompg. it with a strong inorg. acid.