Hydrochloric Acid → HCID 14500682, compound

Participants

Reaction Steps

A stirred slurry of 4-(2-methylphenyl)-3-thiosemicarbazide, 15.3 g (0.08 mole), in 100 mL of absolute ethanol was treated under nitrogen atmosphere with ethyl 2-chloroacetoacetate, 13.61 g (0.08 mole). After stirring for 1 hr the slurry had turned from white to yellow with most of the material going into solution. The reaction mixture was treated with 50 mL of 2N ethanolic hydrogen chloride and stirred for 18 hr., after which the reaction mixture was heated at reflux for 2 hours. A clear orange solution was decanted from some residual material. The hot solution was filtered through a sintered glass filter and the filtrate concentrated in vacuo to give a yellow solid residue. This residue was dissolved in 500 mL of acetone and 50 mL methanol. After filtering, the volume of the filtrate was concentrated to 125 mL under nitrogen atmosphere. The product was allowed to crystallize at ~7-10° C. for ~72 hr. Some sulfur crystals separated and were removed by filtration. The filtrate was again concentrated in vacuo to a solid. The solid was dissolved in hot acetone and upon cooling at ~7-10° C., long needle-like crystals formed and redissolved on warming to room temperature. The solution was treated with water and overnight gave pale, yellow needle-like crystals which, after drying, weighed 15 g, mp 156°-160° C. After 3 recrystallizations from benzene/ligroin a fine white crystalline solid was obtained (8.6 g, mp 160°-161° C.).

Provenance & Evidence