The synthesis of several new Mannich bases was accomplished by the condensation of secondary amines and formaldehyde with the following compounds: (1) 2-pyrrolidone, (2) 2,4-thiazolidinedione, (3) hydantoin, (4) 5,5-dimethyl-hydantoin, (5) uracil, (6) ethylnitramine, and (7) n-butylnitramine.