Chiral 1,2-amino alcohols and 1,2-diols are common structural motifs found in a vast array of natural and biologically active molecules.1 Recently, significant efforts have been applied toward the development of direct catalytic asymmetric approaches to the construction of these units based on the addition of unmodified R-hydroxyketones to imines or aldehydes in Mannich-type and aldol reactions...

In the presence of a Brønsted acid catalyst, both aldehydes and N-Boc-aminals were converted to enecarbamates and N-Boc-iminium salts as activated nucleophiles and electrophiles, respectively, giving unprecedented Mannich adducts. The asymmetric variant of the present Mannich reaction has also been demonstrated with a chiral phosphoric acid catalyst.

Propargylamines are important intermediates for the synthesis of polyfunctional amino derivatives and natural products and biologically active compounds. The classic method of synthesizing chiral propargylamines involves the asymmetric alkynylation of imines. Here, we report a significant advance in the catalytic asymmetric Mannich-type synthesis of propargylamines through catalytic asymmetric ...

The Mannich reaction of 7-aryl-5,6-dihydropyrido[2,3-d]pyrimidines 3, easily accessible by condensation of 6-amino-1,3-dimethyluracil (1) with Mannich bases 2a – c, gives rise to a mixture of 7-aryl-6-(N,N-dimethylaminomethyl)pyrido[2,3-d]pyrimidines 6 and 7 as well as 1,2-bis(7-arylpyrido[2,3-d]pyrimidin-6-yl)ethane 13 the ratio of which depends on the reaction conditions and the amine used. 6...

3 Acknowledgements 5 Abbreviations 6 Part 1: Stereoselective Synthesis of Pyrrolidinones via Nitro-Mannich Reaction

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 ...

We report the development of direct catalytic, enantioselective, anti-selective Mannich-type reactions between unmodified ketones and alpha-imino esters under mild conditions. The reactions were performed using 5-10 mol % of (R)-3-pyrrolidinecarboxylic or (R)-beta-proline as catalyst in an environmentally benign solvent, 2-PrOH, at room temperature. The anti-Mannich products were obtained in go...

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...