Sodium Hydroxide → N-(2-Chloro-6-Methylphenyl)-N'-(1,4,5,6-Tetrahydropyrimidin-2-yl)urea Monohydrochloride Hemihydrate

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Reaction Steps

A mixture of 8.14 g (0.060 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 0.5 hours at room temperature and then 15 g Na2SO4 was added. After stirring for 0.5 hours, a solution of 6.70 g (0.040 mol) of 2-chloro-6-methylphenyl 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 25 ml of 10% HCl and 25 ml of H2O with warming. After filtration through diatomaceous earth chilling in ice gave the crystalline hydrochloride which was recrystallized from cold H2O after treatment with charcoal affording 7.15 g (59%). This material was dried in vacuo (20° C., 5 mm Hg) to constant weight to give 7.11 g (59%) of pure N-(2-chloro-6-methylphenyl)-N'-(1,4,5,6-tetrahydropyrimidin-2-yl)urea monohydrochloride hemihydrate, m.p. (190) 215°-220° C. melts, then forms a new solid; m.p. 243°-245° C.; IR(CHCl3) 3224, 1713, 1677, 1641, 1543 cm-1 ; UV max. (MeOH) 236 (ε16,200) and 217 nm infl (ε21,500).

Provenance & Evidence