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Syntheses of 4‐(2‐hydroperoxy‐2,2‐diarylethyl)‐3,5‐dimethylpyrazoles, 4‐(2‐hydroxy‐2,2‐diarylethyl)‐3,5‐dimethylpyrazoles and the related compounds
Author(s) -
Ouyang Jie,
Nishino Hiroshi,
Kurosawa Kazu
Publication year - 1996
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.5570330448
Subject(s) - chemistry , methanol , acetic acid , manganese , medicinal chemistry , organic chemistry
The reactions of 1,1‐disubstituted ethenes with 2,4‐pentanedione in the presence of manganese(III) acetate and atmospheric oxygen yielded 4‐acetyl‐6,6‐diaryl‐3‐methyl‐1,2‐dioxan‐3‐ols. The latter gave 4‐(2‐hydroperoxy‐2,2‐diarylemyl)‐3,5‐dimethylpyrazoles by the reaction with hydrazines in methanol‐acetic acid (1:1 v/v) at 50° in 15‐77% yields, or 4‐(2‐hydroxy‐2,2‐diarylethyl)‐3,5‐dimethylpyrazoles by the reaction with hydrazines in methanol in 2‐78% yields. The acid‐catalyzed reaction of 4‐(2‐hydroperoxy‐2,2‐diarylethyl)‐3,5‐dimethylpyrazoles yielded 4‐(aroylmethyl)‐3,5‐dimethylpyrazoles (15‐55%) and 4‐(2,2‐diarylethenyl)‐3,5‐dimethylpyrazoles (9‐29%).