105591-66-0Relevant articles and documents
Synthesis and Reactions of Some 4-Oxo-4H-1-benzopyran-2-carboxaldehydes
Sami, S. M.,Ibrahim, S. S.,Abdel-Halim, A. M.,Aly, Y. L.
, p. 384 - 389 (2007/10/02)
Some new 4-oxo-4H-1-benzopyran-2-carboxaldehydes (III) have been prepared, and the conversion of the 2-carboxaldehyde group in III into 2-carbonitrile and 2-carboxylic acid groups has been discussed.Unlike the general behaviour of the 4-oxo-4H-1-benzopyrans towards some nucleophiles, where the reaction takes place with opening of the pyronering, the 6-methyl- and 6-chloro-4-oxo-4H-1-benzopyran-2-carboxaldehydes (IIIa and IIIb) have been found to react with different nucleophiles such as hydroxylamine hydrochloride, hydrazine, phenylhydrazine and primary aromatic amines to give the corresponding condensation products (IV, VII, VIII, X, XI) without the opening of pyrone ring.The only exception to this observation is the reaction of IIIa and IIIb with ethylene diamine where the opening of pyronering does not take place to give the expected 5,6-dihydropyrazine derivatives (XIIa and XIIb).The reactions of IIIa and IIIb with active methylene compounds, malonic acid, malonodinitrile, cyanoacetic acid, ethyl cyanoacetate, cyanoacetamide and hippuric acid have also been discussed.
