Synthesis of 5-Oxo-5H-[1]benzopyrano[4,3-b]pyridine Derivatives

Abstract

5 -O x o -5 H -[ 1 ] b e n z o p y r a n o I 4 , 3 -b ] p y r i d i n ~l were synthesized by the reaction of 4-0x0-4H-I-benzopyran-3-carbonitriles ( 1 1 with malonamide in the presence of sodium methoxide.Compounds ( 1 1were also converted into carboxylic acids and tetrazole derivatives.The structures of , & and their derivatives were confirmed by IR and NMR spectra and by X-ray crystallographic analysis.The discovery that disodium cromoglycate possesses prophylactic properties for bronchial asthma, prompted many laboratories to search for similar antiallergic compounds including chromones, xanthones.quinolones and many related ring