502770-17-4Relevant academic research and scientific papers
Direct catalytic asymmetric synthesis of highly functionalized tetronic acids/tetrahydro-isobenzofuran-1,5-diones via combination of cascade three-component reductive alkylations and Michael-aldol reactions
Ramachary, Dhevalapally B.,Kishor, Mamillapalli
supporting information; experimental part, p. 2859 - 2867 (2010/08/21)
A practical and sustainable chemical process for the synthesis of highly substituted tetrahydro-isobenzofuran-1,5-diones was achieved for the first time through asymmetric cascade Michael-aldol reaction of 4-hydroxy-3-alkyl-5H-furan- 2-ones with alkyl vinyl ketones in the presence of a catalytic amount of l-proline or 9-amino-9-deoxyepiquinine/TCA. In this article, we discovered for the first time the asymmetric synthesis of privileged bicyclic lactones through kinetic resolution and show the synthetic application to pharmaceuticals and natural products synthesis.
3-(Nitrobenzylidene)-2,4(3H,5H)-furandiones in the Hantzsch pyridine synthesis, part 1.: A new approach to furo[3,4-b]pyridines
Goerlitzer,Bartke
, p. 672 - 678 (2007/10/03)
The nitrobenzylidenefurandiones 7 react with acetoacetic ester (8) and ammonium acetate or 3-aminocrotonic esters (9a, b) and 2-aminopent-2-en-4-on (9c), respectively heating in acetic acid to yield the tetrahydrofuro[3,4-b] pyridines 10. The dehydrogenation of 10 using nitric acid or activated manganese dioxide leads to the dihydrofuro[3,4-b]pyridines 12. When the reaction is carried out with the tetronic acid derivatives 7 and the enaminocarbonyl compounds 9 at 30°C in tert-butanol the hexahydro-7a-hydroxyfuro[3,4-b]pyridines 11 are obtained. Treating the N,O-acetales 11 with acetic anhydride in pyridine affords the annulated lactones 10.
