Abstract Urea, thiourea and some N′-alkyl (di) substituted ureas and thioureas were found to react as the amine component in Mannich-type condensation reactions with p-toluene-or phenylmethane-sulfinic acid and aldehydes. Mono-or di-alkylation products are formed in good yields depending on the N′-and N′-substituents in the substrate, while N, N, N′- trimethylurea or-thiourea failed to react. N′-Hydroxy-N′-phenylthiourea is alkylated on ...