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Synthesis and comparative study of reactivities of δ‐lactone, estor group and oxazinone ring in coumarin derivatives towards carbon or nitrogen nucleophiles
Author(s) -
ElKafrawy,
; Soliman,
) Baker,
Abdallah S.R. Mohamed,
ElKady
Publication year - 1990
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19900080512
Subject(s) - chemistry , nucleophile , acetamide , ring (chemistry) , anthranilic acid , coumarin , reagent , medicinal chemistry , lactone , organic chemistry , bicyclic molecule , catalysis
Condensation of methyl 7‐methylcoumarin‐4‐acetate ( 2 ) with primary amines and with anthranilic acid gave 7‐methyl‐2‐oxo‐ N ‐aryl‐2 H ‐[1]‐benzopyran‐4‐acetamide ( 4a—d ) and (7), respectively. Compound 7 underwent cyclization to give 2‐(7‐methyl‐2‐oxo‐2 H ‐[1]‐benzopyran‐4‐yl)‐methyl‐4 H ‐3,1‐benzoxazin‐4‐one ( 3 ). The reaction of 3 with aromatic amines gave the corresponding quinazolone derivatives 5 which tautomerises to the thermodynamically more stable isomer 6 , whereas its reaction with Grignard reagents and aromatic aldehydes gave 8a, 8b , and 9a, 9b , respectively.