476469-28-0Relevant articles and documents
Organocatalysed decarboxylative protonation process from Meldrum's acid: Enantioselective synthesis of isoxazolidinones
Tite, Tony,Sabbah, Mohamad,Levacher, Vincent,Briere, Jean-Francois
supporting information, p. 11569 - 11571 (2013/12/04)
An asymmetric organocatalysed decarboxylative protonation reaction allowed a straightforward synthesis of α-substituted isoxazolidin-5-ones from readily available 5-substituted Meldrum's acids. This process is initiated by an anionic formal (3+2) cycloaddition-fragmentation, generated in-situ from a sulfone-amide precursor which also served as a latent source of proton.
Multi-catalysis cascade reactions based on the methoxycarbonylketene platform: Diversity-oriented synthesis of functionalized non-symmetrical malonates for agrochemicals and pharmaceuticals
Ramachary, Dhevalapally B.,Venkaiah, Chintalapudi,Reddy, Y. Vijayendar,Kishor, Mamillapalli
supporting information; scheme or table, p. 2053 - 2062 (2009/09/05)
In this paper we describe new multi-catalysis cascade (MCC) reactions for the one-pot synthesis of highly functionalized non-symmetrical malonates. These metal-free reactions are either five-step (olefination/hydrogenation/alkylation/ ketenization/esterif
Development of pharmaceutical drugs, drug intermediates and ingredients by using direct organo-click reactions
Ramachary, Dhevalapally B.,Kishor, Mamillapalli,Reddy, Y. Vijayendar
supporting information; experimental part, p. 975 - 993 (2009/04/11)
Here we report on our studies of the use of combinations of amino acids, amines, K2CO3 or Cs2CO3 and CuSO4/Cu for catalysing green cascade reactions. We aimed to prepare the highly reactive and substituted olefin species 7 and 8, under very mild and environmentally friendly conditions, thus giving the hydrogenated products 10 and 12 through the action of Hantzsch ester (4) by self-catalysis through decreasing the HOMO-LUMO energy gaps between olefins 7/8 and Hantzsch ester (4) through biomimetic reductions. Highly useful compounds 10 to 14 were assembled from simple substrates such as aldehydes 1, ketones 2, CH acids 3, Hantzsch ester (4) and alkyl halides 5 by diversity-oriented green synthesis involving cascade olefination/hydrogenation (O/H), olefination/hydrogenation/alkylation (O/H/A) and hydrogenation/olefination/hydrogenation (H/O/H) reaction sequences in one-pot fashion with stereospecific organo- and organo-/metal-carbonate catalysis. Highly functionalized diverse compounds such as 10 to 14 are biologically active products and have found wide applications as pharmaceutical drugs, drug intermediates and drug ingredients. For the first time in organocatalysis, we report the O/H/A/TE reaction to furnish high yields of transesterification products 11 by simply mixing the reactants under proline/K2CO3 catalysis conditions. Additionally, a novel organocatalytic H/O/H reaction sequence for the synthesis of alkyl-substituted aromatics has been developed. Furthermore, for the first time we have developed organocatalysed cascade olefination/hydrogenation/hydrolysis (O/H/H) reactions to furnish highly useful materials such as 2-oxochroman-3-carboxylic acid (14kc) and 2-amino-4H-chromene-3-carbonitrile (14kj) in good yields. Experimentally simple and environmentally friendly organocatalytic two-carbon homologation through cascade O/H/H reactions of aldehydes 1, Meldrum's acid (3c), Hantzsch ester (4) and acetic acid/triethylamine in ethanol has been demonstrated. Additionally, we have developed a green synthesis of the highly substituted 1,2,3-triazole 17 from simple substrates through a two-step combination of olefination/hydrogenation/alkylation and Huisgen cycloaddition reaction sequences under stereospecific organocopper catalysis conditions. In this paper we have found strong support for our hypothesis that, "decreasing the HOMO-LUMO energy gap between olefins 7/8 and Hantzsch ester (4) will drive the biomimetic hydrogenation reaction by self-catalysis". This self-catalysis was further confirmed with many varieties of examples. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
A novel and green protocol for two-carbon homologation: A direct amino acid/K2CO3-catalyzed four-component reaction of aldehydes, active methylenes, Hantzsch esters and alkyl halides
Ramachary, Dhevalapally B.,Kishor,Ramakumar
, p. 651 - 656 (2007/10/03)
A novel and green approach for the two-carbon homologation of aldehydes using amino acid catalysis has been developed and further extended to the generation of pharmaceutically active cyano-esters via four-component reactions in one-pot.
Facile synthesis of α-substituted acrylate esters
Hin, Bunda,Majer, Pavel,Tsukamoto, Takashi
, p. 7365 - 7368 (2007/10/03)
Treatment of 5-monosubstituted Meldrum's acids with dimethylmethyleneimmonium iodide (Eschenmoser's iodide salt) in methanol gives α-substituted acrylate methyl esters in good yields. Easy access to 5-monosubstituted Meldrum's acids allowed us to synthesize a wide variety of α-substituted acrylate methyl esters. The reaction conditions are mild and tolerate many functional groups commonly used in organic synthesis; thus, this new method has potential as an alternative to conventional preparative methods for α-substituted acrylate esters.
