Tetrahedron

Synthesis of Coumarin Derivatives from 4-Oxo-4H-1-benzopyran-3-carboxaldehyde via 3-(Arylaminomethylene) chroman-2, 4-dione

C Bandyopadhyay, KR Sur, R Patra, A Sen

Index: Bandyopadhyay, Chandrakanta; Ranabir Sur, Kumar; Patra, Ranjan; Sen, Arunabha Tetrahedron, 2000 , vol. 56, # 22 p. 3583 - 3587

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Citation Number: 39

Abstract

The attack of the primary amino group at the 2-position of aldehyde 1 11 with concomitant opening of the pyran ring and recyclisation gives the intermediate 4 which needs oxidation to form 5 (Scheme 1). This oxidation may be accomplished by clay itself or by Schiff-base 3. Oxidation of 4-t-butylphenol by K-10 montmorillonite doped with Fe(III) ion, 12 that of secondary as well as benzylic alcohols by clayfen 13. and 14. and aromatisation of 1,4-dihydropyridine by ...