RING TRANSFORMATIONS OF 1-OXA-5,6-DIAZASP IRO[2.4]HEPT-6-EN-4-ONES INTO 4,5-DIHYDRO-4-HYDROXY-1H-PYRAZOLE-4-CARBOXYLIC ACID-DERIVATIVES

Authors
KIRSCHKE K HUBNER P LUTZE G GRUNDEMANN E RAMM M
Citation
K. Kirschke et al., RING TRANSFORMATIONS OF 1-OXA-5,6-DIAZASP IRO[2.4]HEPT-6-EN-4-ONES INTO 4,5-DIHYDRO-4-HYDROXY-1H-PYRAZOLE-4-CARBOXYLIC ACID-DERIVATIVES, Liebigs Annalen der Chemie, (2), 1994, pp. 159-165
Citations number
16
Categorie Soggetti
Chemistry
Journal title
Liebigs Annalen der Chemie → ACNP
ISSN journal
01702041
Issue
2
Year of publication
1994
Pages
159 - 165
Database
ISI
SICI code
0170-2041(1994):2<159:RTO1II>2.0.ZU;2-6
Abstract
Spiro epoxides 3 were synthesized from 1H-pyrazol-5(4H) ones 1 by Knoe venagel condensation with acetone or benzaldehyde and subsequent epoxi dation of 2 with hydrogen per oxide. 3 reacts with nucleophiles under ring transformation to 4,5-dihydro-4-hydroxy-1H-pyrazole-4-carboxylic acid derivatives 5. In three cases the intermediate 6 was isolated. 5b , c undergo by dehydrogenation with chloranil rearrangement to 4,5-dih ydro-4-oxo-1H-pyrazole-5-carboxylic acid derivatives 7b, c.