1-(2-Furoyl)-3-Thiosemicarbazide

Abstract

A mixture of 28 g (0.22 mole) of thiosemicarbazide hydrochloride and 150 ml of dry pyridine was boiled for 20–25 minutes in a 300-ml four-necked round-bottomed flask fitted with mercurysealed stirrer, dropping funnel, and reflux condenser protected by a calcium chloride tube. The contents of the flask were stirred and cooled with ice and salt to a temperature of from −7° to −5°, and 26.1 g (0.2 mole) of 2-furoyl chloride (see p. 56), b.p. 89–90°//32 mm, was added dropwise at such a rate that the temperature of the mixture did not rise above −3° (Note 1); 1.5–2 hours was required for the addition of the acid chloride. When the addition was complete, without removal of the bath stirring was continued for four hours (the temperature gradually rose to that of the room); the mixture was then left overnight.