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A convenient synthesis of 3‐aryl‐4 H ‐ Benzopyrano[3,4‐ d ]isoxazol‐4‐ones
Author(s) -
Litinas Konstantinos E.,
Nicolaides Demetrios N.,
Varella Evangelia A.
Publication year - 1990
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570270354
Subject(s) - chemistry , nitrile , regioselectivity , aryl , cycloaddition , pyridine , 1,3 dipolar cycloaddition , cleavage (geology) , medicinal chemistry , stereochemistry , organic chemistry , catalysis , alkyl , geotechnical engineering , fracture (geology) , engineering
Regioselective 1,3‐dipolar cycloaddition of nitrile oxides 5a‐c to ethyl o ‐hydroxycinnamate (3) gave the corresponding ethyl trans ‐3‐aryl‐4,5‐dihydro‐5‐(2‐hydroxyphenyl)‐4‐isoxazolecarboxylates 6a‐c . Their structure was confirmed by reductive cleavage to 1 and compounds 9a‐c . Compounds 6a‐c afforded upon heating in the presence of pyridine the 3‐aryl‐4 H ‐[1]benzopyrano[3,4‐ d ]isoxazol‐4‐ones 11a‐c . Compound 10c was also isolated from 6c and transformed thermally into 11c .