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Synthesis of hydroxypyrazoles and 1-methyl-3-isoxazolones via haloform reactions

✍ Scribed by Alex F.C. Flores; Nilo Zanatta; Adriano Rosa; Sergio Brondani; Marcos A.P. Martins

Publisher: Elsevier Science
Year: 2002
Tongue: French
Weight: 136 KB
Volume: 43
Category: Article
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(02)00874-2

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✦ Synopsis

The synthesis of a new series of hydroxypyrazoles (2a-f) and 2-methyl-3-isoxazolones (3a-d) from the cyclocondensation reaction of trichloromethyl-substituted 1,3-dielectrophiles (1a-f) with dry hydrazine and N-methylhydroxylamine is reported. The regiospecific cyclocondensation took place with the elimination of the trichloromethyl group in a haloform type reaction when acetonitrile under basic medium was used. The structure of compounds 2 and 3 were determined mainly by 1 H and 13 C NMR spectroscopy.

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