Condensation reactions involving the carboxamido group of tetracycline have been reported hy Gottstein, et a/.! These workers describe an xanthydrol condensate of tetracycline as well as numerous derivatives prepared from amines and formaldehyde by the Einhorn reaction. One of these, S-(pyrrolidi~ iomcthyl)-tetr:~-(yc'line, 2 has proved superior to tetracyclinc when administered parenterally.? 4
