The decarboxylative Mannich reaction (DMR) of b-ketoacids with imines has emerged as a very important tool for the synthesis of natural products and biologically active compounds. The elegant work of Robinson on the total synthesis of ( )-tropinone represents the first practical example of utilizing the DMR as a key step in organic synthesis. Herbert and co-workers and Mangla and Bhakuni then d...

Four series of N-Mannich bases of 3,4-dihydropyrimidine-2(1H)-thiones 7a-g, 8a-g, 9a-g and 10a-g (DHPMs) have been prepared by Mannich reaction with seven different heterocyclic secondary amino compounds 6a-g and formaldehyde 5. In this reaction, four different derivatives of 3,4-dihydropyrimidine-2(1H)-thiones 4a-d have been used as hydrogen active compound. These precursors have been derived ...

The direct three component modified Mannich reaction via condensation of aldehydes, 2-naphthol or 2,7-naphthalendiol and piperidine to generate Betti bases has been carried out over L-proline (20 mol%) with high efficiency under solvent free conditions at 70 OC. Also, the reaction of aromatic aldehyde and 4-hydroxycoumarin in the presence of L-proline (20 mol%) in the ethanol under reflux condi...

In the present study, a series of Mannich bases was synthesized by condensing 4,6-diacetylresorcinol with formaldehyde and some selected secondary amines following the Mannich reaction conditions. Findings revealed that Mannich reaction did not take place at the acetyl function but occurred on the aromatic ring position between the two hydroxyl groups. It was also observed that in one case inst...

A novel series of Mannich bases containing isoniazid were prepared. First, reaction of 2-propoxybenzaldehyde with isoniazid gave the corresponding hydrazone (2a). Subsequently, product 2a after the Mannich reaction of aminomethylation with formaldehyde and secondary amines gave 2b–k. The inhibitory potencies of the synthesized compounds were assayed in vitro against a panel of microorganisms an...

In an effort to develop anticancer agents, a series of Mannich bases were prepared by Mannich reaction. When one biologically active molecule is linked to another, the resultant molecule generally has increased potency. Hence two pharmacophores, i.e. quinazoline ring and amine moiety are fused to obtain highly potent, more specific and less toxic agent. In the present study, synthesis of novel ...

Here we describe our studies on solvent-dependent enantiodivergent Mannich-type reactions utilizing conformationally flexible guanidine/bisthiourea organocatalyst (S,S)-1. Our mechanistic investigations revealed that the stereo-determining steps in both the (R)- and (S)-selective Mannich-type reactions are governed by the cooperative effect of guanidine and thiourea in the inherently monomeric ...