(1,1-Dimethylethyl)urea → Ethyl 2-[(1,1-dimethylethyl)amino]-5-(3-chlorophenyl)-4-oxazolecarboxylate
Reaktionsgleichung
Cl[CH:2]([C:10]1[CH:15]=[CH:14][CH:13]=[C:12]([Cl:16])[CH:11]=1)[C:3](=O)[C:4]([O:6][CH2:7][CH3:8])=[O:5].[C:17]([NH:21][C:22]([NH2:24])=[O:23])([CH3:20])([CH3:19])[CH3:18]>>[CH3:18][C:17]([NH:21][C:22]1[O:23][C:2]([C:10]2[CH:15]=[CH:14][CH:13]=[C:12]([Cl:16])[CH:11]=2)=[C:3]([C:4]([O:6][CH2:7][CH3:8])=[O:5])[N:24]=1)([CH3:20])[CH3:19]Komponenten
3
Versuchsvorschrift
A reaction vessel was charged with 6.5 g (25 mmol) of ethyl 3-chloro-3-(m-chlorophenyl)pyruvate and 2.9 g (25 mmol) of tert-butyl urea. The reaction mixture was heated at 105°-115° C. for 2 hours. The mixture was cooled to ambient temperature and 1.71 g of tert-butyl urea starting material was removed by crystallization in hexane-ethyl acetate solution. The remaining 10.16 g of a brown oil was subjected to Kugelrohr distillation (70°-80° C. @ 0.3 mm Hg) to yield 5.08 g of a gold viscous oil. This oil was chromatographed on silica gel using a Waters Prep 500 system and 10% ethyl acetate-in-hexane eluent to yield product identified in Table 1.