3-Chloro-2,4-pentanedione → 2-Benzylthio-6-chloro-5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine

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Reaction Steps

To a suspension of 153 g (0.74 mol) 3-amino-5-benzylthio-1,2,4-triazole in 250 ml of glacial acetic acid was added 100 g (0.74 mol) of 3-chloro-2,4-pentanedione in a dropwise manner. The reaction mixture was heated at reflux for 18 hours and cooled to room temperature. The reaction mixture was poured over ice and the oil which separated solidified upon stirring. The solid was collected by filtration and recrystallized from methanol to yield 116 g (79%) of the desired product as an off white solid, m.p. 164°-166° C. IR and 1H NMR spectra were in agreement with the assigned structure.

Provenance & Evidence