Organocatalytic Asymmetric Synthesis of 3,3-Disubstituted 3,4-Dihydro-2-quinolones
作者:Soumendranath Mukhopadhyay、Utpal Nath、Subhas Chandra Pan
DOI:10.1002/adsc.201700655
日期:2017.11.23
The first organocatalyticasymmetric reaction employing 3,4-dihydro-2-quinolone has been developed leading to the synthesis of biologically important 3,3-disubstituted-dihydro-2-quinolones. Cinchona alkaloid derived bifunctional amino-thiourea catalysts were found to be the best catalysts. The products were obtained in high enantio- and good diastereoselectivities and also few synthetic transformations
The metalcarbonyls Fe(CO)5˙ Ru3(CO)12, and Rh6(CO)16 are catalysts for the deoxygenation of ortho-nitrostyrenes under carbonmonoxide pressure to give indole derivatives; the crystal structure of a non-catalytically active rhodium complex obtained during the synthesis of (5e) is reported.
Organocatalytic Asymmetric Mannich Reaction of Dihydro-3-carboalkoxy-2-quinolones with Preformed<i>N</i>-Boc Imines
作者:Soumendranath Mukhopadhyay、Subhas Chandra Pan
DOI:10.1002/ejoc.201900156
日期:2019.4.24
An organocatalytic enantioselective Mannichreaction between dihydro‐3‐carboalkoxy‐2‐quinolones and preformed N‐Boc imines has been developed. Quinine derived thiourea catalyst was found to be effective to provide the desired products in good yields and with good enantioselectivities.
A series of substituted aryl malonamates have been prepared. These compounds are analogues of aryl phenaceturates where the amido side chain has been replaced by a retro-amide. Like the phenaceturates, these compounds are substrates of typical class A and class C beta-lactamases, particularly of the latter, and of soluble DD-peptidases. The effect of substituents alpha to the ester carbonyl group on turnover by these enzymes is similar to that in the phenaceturates. On the other hand, N-alkylation of the side chain amide of malonamates, but not of phenaceturates, retains the susceptibility of the compounds to hydrolysis by beta-lactamases. This reactivity is not enhanced, however, by bridging the amide nitrogen and C alpha atoms. A phosphonate analogue of the malonamates was found to be an irreversible inhibitor of the beta-lactamases. These results, therefore, provide further evidence for the covalent access of compounds bearing retroamide side chains to the active sites of beta-lactam-recognizing enzymes. (C) 2009 Elsevier Ltd. All rights reserved.