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Synthesis and reactions of 4‐isopropylidene‐1‐aryl‐3‐methyl‐2‐pyrazolin‐5‐ones
Author(s) -
Deruiter Jack,
Carter Deborah Ann,
Arledge Wilmer Scott,
Sullivan Patrick J.
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.5570240128
Subject(s) - chemistry , hydrazine (antidepressant) , steric effects , yield (engineering) , piperidine , tautomer , conjugate , medicinal chemistry , aryl , hydrogen peroxide , organic chemistry , potassium cyanide , cyanide , alkyl , mathematical analysis , materials science , mathematics , chromatography , metallurgy
The reactions of 4‐isopropylidene‐1‐aryl‐3‐methyl‐2‐pyrazolin‐5‐ones 4a‐d were investigated under a variety of conditions. In the presence of thiols or piperidine, 4a‐d failed to yield conjugate addition products, presumably due to the steric bulk provided by the two methyl substituents of the isopropylidene side chain. Reaction of 4a‐d with hydrazine derivatives gave the 1‐aryl‐3‐methyl‐2‐pyrazolin‐5‐ones 3a‐d and isopropyl‐hydrazones. Treatment of 4a with potassium cyanide yielded a stable conjugate addition product which exists as a mixture of tautomers in different solvents. Also, oxidation of 4a with hydrogen peroxide gave a spiroepoxide 22 , while m ‐chloroperbenzoic acid oxidation afforded both the spiroepoxide 22 , and a small quantity of a hydroxyspiroepoxide 23.