Synthesis of 1-methyl-, 4-nitro-, 4-amino- and 4-iodo-1,2-dihydro-3H-pyrazol-3-ones

Citation
Yc. Fiamegos et al., Synthesis of 1-methyl-, 4-nitro-, 4-amino- and 4-iodo-1,2-dihydro-3H-pyrazol-3-ones, J HETERO CH, 38(5), 2001, pp. 1065-1069
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
JOURNAL OF HETEROCYCLIC CHEMISTRY
ISSN journal
0022-152X → ACNP
Volume
38
Issue
5
Year of publication
2001
Pages
1065 - 1069
Database
ISI
SICI code
0022-152X(200109/10)38:5<1065:SO144A>2.0.ZU;2-I
Abstract
4-Aminopyrazole-3-ones 4b, e, f were prepared from pyrazole-3-ones 1b-d in a four-step reaction sequence. Reaction of the latter with methyl p-toluene sulfonate gave 1-methylpyrazol-3-ones 2b-d. Compounds 2b-d were treated wit h aqueous nitric acid to give 4-nitropyrazol-3-ones 3b-d. Reduction of comp ounds 3b-d by catalytic hydrogenation with Pd-C afforded the 4-amino compou nds 4b, e, C Using similar reaction conditions, nitropyrazole-3-ones deriva tives 2c, d were reduced into aminopyrazole-3-ones 5e, f. 4-lodopyrazole-3- ones 7a, 7c and 8 were prepared from the corresponding pyrazol-3-ones 2a, 2 c and 6 and iodine monochloride or sodium azide and iodine monochloride.