- 著者
-
小川 和男
寺田 忠史
本那 隆次
- 出版者
- 公益社団法人日本薬学会
- 雑誌
- Chemical & pharmaceutical bulletin (ISSN:00092363)
- 巻号頁・発行日
- vol.32, no.3, pp.930-939, 1984-03-25
As a part of our search for new potent analgesic agents, novel fused pyrazole derivatives were synthesized. The reaction of 2-substituted-5-hydroxypyrazole (I) with ethyl 2-substituted (for example COCH_3 or CO_2C_2H_5) acylacetates (II) gave mainly pyrazolo [1,2-a] pyrazole-1,5 (1H, 5H)-diones (III). On the other hand, similar reaction of I with diethyl benzoylmalonate gave mainly pyrazolo [5,1-b] [1,3] oxazin-5 (5H)-one (V) but did not give III at all. Thermal and photochemical isomerization of III gave V. Methanolysis of IIIa in the presence of LiOH occurred with retention of the 4-ethoxycarbonyl-5-pyrazolone ring and similar products (VIa and VIf) were obtained by methanolysis of Va and Vf, respectively. Analgesic activities of the present new compounds were all inferior to that of aminopyrine.