Ethanol → 2-Chloro-6-methyl-5-nitronicotinonitrile

A suspension of the compound prepared in Example 442 (5.00 g) and phosphorus pentachloride (6.97 g) in phosphorus oxychloride (25 mL) was stirred and heated in an oil bath set to 110° C. for 30 minutes. The resulting solution was cooled to ambient temperature and concentrated. The residual liquid was cooled in an ice bath, whereupon a solid formed. This solid was carefully treated with 50% aqueous ethanol (10 mL), and then the mixture was stirred and heated in the 110° C. oil bath for 5 minutes. This redissolved the solid, and then the flask was again placed in the ice bath. The solid reappeared on cooling, and it was collected by filtration, washed with water, and air-dried. The solid was then recrystallized by stirring it with methanol (20 mL), and heating to boiling until all solid dissolved. On cooling to ambient temperature crystallization began, and the mixture was stored in the refrigerator overnight. The crystals were collected by filtration, washed with cold methanol, and dried under vacuum to provide the title compound (2.09 g) with the following physical data.