3‐Methylpiperidine, 4‐methylpiperidine, and 2, 6‐dimethylmorpholine were used to condense separately with sixteen different ketones and paraformaldehyde to yield various Mannich bases. All the hydrochlorides of Mannich bases prepared in this work were tested for their solubilities in water, in 0.1N hydrochloric acid and in 0.1N sodium hydroxide.