Methyl iodide → Malononitrile

Reaction equation

CI.[NH2:3][C:4]1[CH:9]=[C:8](N)[NH:7][C:6](=[S:11])[N:5]=1>[OH-].[Na+]>[NH2:5][C:6]([NH2:7])=[S:11].[C:8](#[N:7])[CH2:9][C:4]#[N:3]

Participants

Procedure

Methyl iodide (169.0 g., 1.19 mole) is added in one portion to a stirred solution of 4,6-diaminopyrimidine-2(1H)thione (146 g., 1.02 mole) in 1.0 liter 1N sodium hydroxide. The thione starting material is obtained by reaction of thiourea and malononitrile according to Kikugawa, et al., Chem. Pharm. Bull., 25(7), 1811-1821 (1977). In about five minutes following the addition a precipitate forms. After stirring overnight, the reaction mixture is filtered and air-dried affording 135.1 g. (81%) of 4,6-diamino-2-(methylthio)pyrmidine; m.p. 185°-186° (recrystallized from acetonitrile).