Sodium Hydroxide → N-(1,4,5,6-tetrahydropyrimidin-2-yl)-N'-(2-trifluoromethylphenyl)urea monohydrochloride hydrate

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Reaction Steps

A mixture of 9.90 g (0.073 mol) of 2-amino-1,4,5,6-tetrahydropyrimidine hydrochloride, 6.0 g (0.075 mol) of 50% NaOH and 75 ml of THF was stirred for 0.75 hours at room temperature and then 10 g. Na2SO4 was added. After stirring for 0.5 hours, a solution of 9.36 g. (0.050 mol) of methyl-2-trifluoromethylphenyl isocyanate in 50 ml of THF was added over a period of 0.5 hours. After stirring for 1 hour, the reaction mixture was filtered, the filtrate evaporated in vacuo and the residue dissolved in 50 ml of 10% HCl and 100 ml of H2O with warming. After filtration through a pad of diatomaceous earth, chilling in ice gave the crystalline hydrychloride which was recrystallized from hot H2O affording 10.09 g (63%). This material was dried to constant weight in vacuo (20° C., 5 mm Hg) to give pure N-(1,4,5,6-tetrahydropyrimidin- 2-yl)-N'-(2-trifluoromethylphenyl)urea monohydrochloride hydrate; m.p. (120) 182.5°-184.5° C. IR(CHCl3) 3240 (br), 1717, 1642, 1594 cm-1. UV max. (MeOH) 281 infl (ε6,900), 256 nm (ε29,000) and 215 nm (ε14,900).

Provenance & Evidence