S. Seema, Surender Kumar, J. K. Makrandi
Jun 1, 2005
Citations
0
Influential Citations
0
Citations
Journal
ChemInform
Abstract
Synthesis of 3-cyano and 3-cyano-4-methylcoumarins have been achieved by the reaction of 2-hydroxybenzaldehydes/2- hydroxyacetophenones with malanonitrile in biphase medium using phase transfer catalysis. IPC: Int.Cl. 7 C 07 D 311/00 3-Cyanocoumarins are considered to be important compounds as they are required for the synthesis of methine dyes, 1 3-carboxycoumarins 2,3 which are used for the synthesis of cephalosporins, 4 modified penicillins, 5 oxygen-bridged tetrahydropyridones 6 etc. The amide obtained from 3-cyanocoumarins 2,3 exhibit specific inhibitors of α-chymotripsin 7 and human leukocyte elastase. 8 But 3-cyanocoumarins have been obtained by reaction of substituted salicyaldehyde with malanonitrile 9 or ethyl cyanoacetate 10 in pyridine or pyridine-pipridine medium in low yields. In a recent report 11 reaction of salicyaldehyde with malanonitrile in aqueous medium has been found to yield 3-carboxycoumarins as ultimate products. In an attempt to prepare 3-cyano-4-methyl coumarins, required for our work, the reaction of 2- hydroxyacetophenones with malanonitrile under reported conditions 11 was found to be incomplete even after a long time due to heterogenous nature of the reaction, as substituted 2-hydroxyacetophenones exhibit extremely poor solubility in the aqueous medium or separate as sodium salt in the reaction mixture.