Premium
1,3‐Dipolar cycloaddition synthesis of 3‐bromo‐5‐substituted isoxazoles, useful intermediates for the preparation of pharmacologically active compounds
Author(s) -
Chiarino D.,
Napoletano M.,
Sala A.
Publication year - 1987
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.5570240109
Subject(s) - chemistry , cycloaddition , regioselectivity , yield (engineering) , reactivity (psychology) , 1,3 dipolar cycloaddition , oxide , combinatorial chemistry , organic chemistry , medicinal chemistry , catalysis , medicine , materials science , alternative medicine , pathology , metallurgy
Bromonitrile oxide 2 , generated from easily available dibromoformaldoxime 1 , reacts with monosubstituted acetylenic derivatives 4 to give 3‐bromo‐5‐substituted isoxazoles 5 in high yield. The experimental conditions necessary to overcome difficulties such as the low reactivity of acetylenic dipolarophiles and the high tendency to dimerization of bromonitrile oxide 2 , are discussed; the regioselectivity of this 1,3‐dipolar cycloaddition is also studied. The obtained improvements in the synthesis of some pharmacologically active compounds are reported.