Mono-Mannich bases, 1-aryl-3-phenethylamino-1-propanone hydrochlorides, 1a, 2a, 3a, 4a, 5a, 6a, 7a, 8a, 9a, and semi-cyclic mono-Mannich bases, 3-aroyl-4-aryl-1-phenethyl-4-piperidinols, 1b, 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b, were synthesized by a non-classical Mannich reaction. The aryl part was: C(6)H(5 )for 1a, 1b; ...