Synthesis and molecular structure of 3-(2-benzyloxy-6-hydroxyphenyl)-5-styrylpyrazoles. Reaction of 2-styrylchromones and hydrazine hydrate

Citation
Dcga. Pinto et al., Synthesis and molecular structure of 3-(2-benzyloxy-6-hydroxyphenyl)-5-styrylpyrazoles. Reaction of 2-styrylchromones and hydrazine hydrate, TETRAHEDRON, 55(33), 1999, pp. 10187-10200
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry & Analysis","Organic Chemistry/Polymer Science
Journal title
TETRAHEDRON
ISSN journal
0040-4020 → ACNP
Volume
55
Issue
33
Year of publication
1999
Pages
10187 - 10200
Database
ISI
SICI code
0040-4020(19990813)55:33<10187:SAMSO3>2.0.ZU;2-J
Abstract
3-(2-Benyloxy-6-hydroxyphenyl)-5-styrylpyrazoles 7a-e were prepared from th e reaction of 2-styrylchromones and hydrazine hydrate. 3-(2-Benzyloxy-6-hyd roxyphenyl)-5-(2-phenylethyl)-pyrazoles pyrazoles 8a,d,e and 3-(2-benzyloxy -beta,6-dihydroxystyryl)-5-aryl-2-pyrazolines 9a-e were also obtained as by -products. The crystal and molecular structure of two 3-(2-benzyloxy-6-hydr oxyphenyl)-5-styrylpyrazoles 7a,b have been determined by X-Ray analysis. A lthough the substitution of an hydrogen by a methyl group on the double bon d of the styryl moiety seems to be a minor perturbation, it produces drasti c changes in the crystal packing where only one conformer is present. The O H group is involved as donor of an intramolecular hydrogen bond and the NH group is responsible for the formation of chains via intermolecular hydroge n bonds. (C) 1999 Elsevier Science Ltd. All rights reserved.