N-(Morpholinomethq. 1)-tetracycline (VI) has been prepared in a high yield by the interaction of tetracycline (I), morpholine and formaldehyde in t-butyl alcohol. Treatment of VI with an aqueous solution of sodium bisulfite and also lowpressure hydrogenolpsis of VI with Raney nickel catalyst have regenerated tetracycline. Other substantial evidence that the rnorpholinomethyl radical is attached to the nitrogen atom of the carboxamido grouping ...