Heptyl-5-cyanocytosine

3-n-HEPTYL-6-CYANOCYTOSINE (2(l)-Pyrimidone, 3-n-heptyl-4(3)-iiruno-5-cyano] 

Submitted by Barbara B. Kehm and Calvert W. Whitehead.1 Checked by M. S. Newman and K. G. Ihrman. 

3-n-Ileptylureidomethylenemalononitrile. In a 250-ml. round-bottomed flask fitted with a heating mantle and a reflux condenser are placed 28.5 g. (0.18 mole) of N-w-heptylurea, 11.9 g. (0.18 mole) 

3-n-Heptyl-5-cyanocytosine. In a 250-ml. Erlenmeyer flask are placed 33.8 g. (0.145 mole) of 3-H-heptylureidomethylenemalononitrile and 70 ml. of methanol then 8.5 g. (0.16 mole) of sodium methoxide (Note 6) is added carefully in small portions (Note 7). The resulting solution is allowed to stand at room temperature for 3 days in the stoppered flask. The contents of the flask are dissolved in 300 ml. of cold water in an 800-ml. beaker, and the solution is stirred as 11 ml. of glacial acetic acid is added. The precipitated solid is collected by suction filtration on a Buchner funnel and washed with three 40-ml. portions of distilled water. The undried product is dissolved in 600 ml. of hot ethyl alcohol then the solution is filtered into a 1-1. flask by gravity through a fluted filter paper, concentrated on the steam bath to 200 ml., and cooled in the refrigerator for 4 hours. The 3-w-heptyl-5-cyanocytosine crystallizes in white needles, melts at 192-197° (Note 8), and amounts to 29.7-31.1 g. (88-92%) (Note 9). 

Recrystallization of 20 g. of this product from 230 ml. of hot ethyl alcohol affords 17.8 g. of fine colorless needles, m.p. 199.5-202.5°. 

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The melting point of 3- -heptyl-5-cyanocytosine is given in the literature4 as 200°. 

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