4-Chlorobenzonitrile → Ethyl 5-(4-chlorophenyl)-1,2,4-thiadiazole-3-carboxylate

Participants

Reaction Steps

A sample of p-chlorobenzonitrile was distilled and then crystallized twice from methylcyclohexane to remove impurities that interfered in the following reaction. A solution of 8.76 g (0.050 mol) of ethyl 2-oxo-1,3,4-oxathiazole-5-carboxylate and 68.8 g (0.50 mol, 10 equiv.) of purified p-chlorobenzonitrile was held at 190° C for 72 hours. The solution, which contained the product in 69% yield, was concentrated under vacuum to 150° C (about 2 torr). The residue was crystallized from heptane (charcoal) to give 8.25 g (61%) of gold crystals, mp 98°-99.5° C. A small sample was crystallized twice from heptane (charcoal) to give a white solid, mp 98°-99.5° C.

Provenance & Evidence