The pyrazole diester (0.5 g, 1.9 mmol) was refluxed for 10 h in 1 mL of ethanol containing 1.84 g of a 15% potassium hydroxide solution. The cold solution was diluted with water (2 mL) and acidified to pH 3.5 with 2 M HC1. The precipitate was filtered and washed with cold water and diethyl ether. Crystallization from water/ethanol yielded pure 19 (0.32 g, 81%): mp 225 OC; UV 222 (4.0); IR (KBr) 3260, 3100, 2980, 2940, 1710, 1580, 1520, 2.66-2.62 (m, ...