𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Ringtransformationen von 1-Oxa-5,6-diazaspiro[2.4]hept-6-en-4-onen zu 4,5-Dihydro-4-hydroxy-1H-pyrazol-4-carbonsäure-Derivaten

✍ Scribed by Kirschke, Klaus ;Hübner, Petra ;Lutze, Gerhard ;Gründemann, Egon ;Ramm, Matthias

Publisher
John Wiley and Sons
Year
1994
Tongue
English
Weight
657 KB
Volume
1994
Category
Article
ISSN
0947-3440

No coin nor oath required. For personal study only.

✦ Synopsis

Ring Transformations of 1‐Oxa‐5,6‐diazaspiro[2.4]hept‐6‐en‐4‐ones into 4,5‐Dihydro‐4‐hydroxy‐1__H__‐pyrazole‐4‐carboxylic Acid Derivatives

Spiro epoxides 3 were synthesized from 1__H__‐pyrazol‐5(4__H__)‐ones 1 by Knoevenagel condensation with acetone or benzaldehyde and subsequent epoxidation of 2 with hydrogen peroxide. 3 reacts with nucleophiles under ring transformation to 4,5‐dihydro‐4‐hydroxy‐1__H__‐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‐dihydro‐4‐oxo‐1__H__‐pyrazole‐5‐carboxylic acid derivatives 7b, c. magnified image

📜 SIMILAR VOLUMES

Bildung von 5,6-Dihydro-1,3(4H)-thiazin-
Bildung von 5,6-Dihydro-1,3(4H)-thiazin-4-carbonsäure-estern aus 4-Allyl-1,3-thiazol-5(4H)-onen
✍ Christjohannes Jenny; Heinz Heimgartner 📂 Article 📅 1989 🏛 John Wiley and Sons 🌐 German ⚖ 538 KB

## Formation of Methyl 5,6-Dihydro-1,3(4H)-thiazine-4-carboxylates from 4-Allyl-1,3-thiazol-5(4H)-ones The reaction of N -[ 1 -(N+V-dimethylthiocarbamoyI)-l -methyl-3-butenyl]benzamid (1) with HC1 or TsOH in MeCN or toluene yields a mixture of 4-allyl-4-methyl-2-phenyl-1,3-thiazol-5(4H)-one (5a) a