Behaviour of 2,3-Dihydro-1H-Benzo[D]Imidazole-2-Thione towards Amines under Mannich-Type Condition †

2,3-Dihydro-1H-benzo[d]imidazole-2-thione (1) was subjected to a Mannich reaction with either dimethylamine, urotropine, morpholine, thiomorpholine, (±) 3,3,5 trimethylhexahydroazepine, piperazine or p-bromoaniline and formalin in different molar ratios to afford the Mannich bases. The reactivity of the Mannich base 5a towards indole was also investigated. In addition the condensation of hydroxymethyl derivative 10 with morpholine, benzimidazole, p-bromoaniline, tryptamine and aminiothiazole was achieved.