One hundred seventy-seven grams (1 mole) of acetoacetanilide is added in small portions by means of a spatula to 185 ml. of concentrated sulfuric acid which has been heated previously to 75° (Note 1) in a 1-l. three-necked flask provided with a mechanical stirrer and a thermometer which extends into the liquid. The temperature of the mixture is maintained at 70–75° by intermittent cooling until nearly all the acetoacetanilide has been added. The last 10–15 g. is added without cooling, and the temperature rises to 95°; the addition requires 20–30 minutes. The heat of reaction maintains the temperature at 95° for about 15 minutes; the reaction mixture is then kept an additional 15 minutes at 95° by external heating. After the solution has cooled to 65°, it is poured into 5 l. of water with vigorous stirring.

After cooling, the product is filtered by suction, washed with four 500-ml. portions of water and two 250-ml. portions of methanol, and air-dried. The yield of 4-methylcarbostyril is 138–144 g. (86–91%). This material, which melts at 219–221°, is suitable for preparing 2-chlorolepidine (p. 194). It may be purified further by recrystallization from 95% ethanol. For recrystallization 39 g. is dissolved in 650 ml. of solvent; the recovery is 33–33.5 g., and the melting point of the product is 222–224°.