Ethyl 2-chloroacetoacetate → HCID 14500732, compound

Participants

Reaction Steps

A stirred slurry of 10.5 g (0.079 mole) of 4-(2-propanyl)-3-thiosemicarbazide in 100 mL of tetrahydrofuran under nitrogen atmosphere was treated with 13 g (0.079 mole) of ethyl 2-chloroacetoacetate. After 30 minutes the reaction mixture became suddenly exothermic, turning green-yellow and amorphous sulfur separated. The reaction mixture was stirred at ambient temperature for 2 hr, diluted with water, made acidic with 3N hydrochloric acid and filtered to remove the insoluble sulfur. The filtrate was adjusted to pH 8 with sodium carbonate and extracted with 3×50 mL of methylene chloride. The extracts were combined, washed with water, dried over magnesium sulfate and the filtrate concentrated in vacuo. The oily residue in acetone was treated with ethereal hydrogen chloride and diluted with an equal volume of isopropyl ether to five the crude product. Recrystallization from acetone gave 6.6 g of large beige crystals, mp 158°-159° C., as the hydrochloride salt.

Provenance & Evidence