ChemInform Abstract: Regioselective Reaction: Synthesis and Biological Activity of Some Mannich Derivatives.

Abstract

The Mannich reaction of 3-(substituted)-4-( I-phenyl- 3-methyl5-chlor0-4-pyrazolidine)amino-5-mercapto-l, 2, 4-triazoles 3 with formaldehyde and appropriate amine results in the regioselective formation of l-aminomethyl-3- (substituted)-4-( l-phenyl-3-methyl5-chlor0-4-pyrazolidine)amino-l, 2, 4-triazole-5-thiones 4. The structures of new compounds have been established by analytical and spectral data. These compounds hav~ been tested for their antifungal and antibacterial activities. 4-Amino-5-mercapto-l, 2, 4-triazoles are the starting materials· for the synthesis of a wide variety of heterocyclic derivatives which are of great importance in medicinal chemistryl. 2. The Mannich bases are associated with potent biological activities such as antibacterial, antifungal, antiviral, antimalarial and CNS depressents 3 • 4 • Similarly the pyrazole nucleus is reported to possess strong bactericidal and fungicidal properties 5 • Keeping in view of these observations and in continuation of our search for biologically active heterocycles,6.7.8 we planned to sythesize the Mannich bases carrying both triazole and pyrazole nucleii, starting from the corresponding 3-(substituted)-4(l-phenyl-3-methyl-5-chloro-4-pyrazolidene )amino, 5mercapto I, 2, 4-triazoles. The Schiff bases 3 on treatment with suitable amines in the presence of formaldehyde underwent Mannich reaction to give the Mannich bases 4 (Scheme I). However, it is interesting to note that the reaction is highly regioselective and furnishes only the N-Mannich base and none of the S-Mannich derivatives, although the Schiff base 3 can exist in thiol-thione tautomeric equilibrium. 3-AlkyI9, aryl 10 or aryloxymethylll substituted-4-amino 5-mercapto-l , 2, 4-triazoles and l-phenyl-3-methyl-5-chloro pyrazo le-4-carboxaldehyde 12 were prepared as per the procedures reported in the literature. Condensation of triazole 1 with aldehyde 2