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Nitrile oxides cycloadditions to cinnamaldehyde. Facile dehydrogenation of 4‐formyl‐4,5‐dihydroisoxazoles
Author(s) -
De Sarlo Francesco,
Guarna Antonio,
Brandi Alberto
Publication year - 1983
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.5570200613
Subject(s) - chemistry , nitrile , cinnamaldehyde , dehydrogenation , cycloaddition , double bond , medicinal chemistry , oxide , structural isomer , organic chemistry , catalysis
Nitrile oxides (1) react with cinnamaldehyde (2) at the ethylenic double bond to give 4‐formyl‐4,5‐dihydro‐isoxazoles (3) as the predominant regioisomers ( 1 H nmr). These primary cycloadducts easily dehydrogenate to the corresponding isoxazoles (4). In the presence of an excess of nitrile oxide (1), either the aldehydes (3) and (4) undergo further cycloaddition at the CO bond yielding the bis‐cycloadducts (5) and (6), respectively.