O-Cresol → 1,3-Dimethyl-5-(methoxycarbonyl-methylene)-hydantoin

Reaction equation

[CH3:1][NH:2][C:3]([NH:5][CH3:6])=[O:4].C/[C:8](/[C:14]([O-:16])=O)=[C:9](\C)/[C:10]([O-:12])=[O:11].[C:17]1(C)C(O)=CC=CC=1>ClC1C=CC=CC=1Cl>[CH3:1][N:2]1[C:8](=[CH:9][C:10]([O:12][CH3:17])=[O:11])[C:14](=[O:16])[N:5]([CH3:6])[C:3]1=[O:4]

Participants

Procedure

44 g of N,N'-dimethylurea were dissolved in 150 g of o-dichlorobenzene and reacted with 72 g of dimethylmaleate for 2 hours at 180°-185° C after the addition of 25 g of cresol. The solvent was removed from this reaction mixture and the residue was fractionated under vacuum, 85 g (= 85% of the theory) of the desired product distilling over at 0.07 Torr and 128° C. A purified product melting at 49.5° C could be obtained by dissolving the crude product in chloroform and reprecipitating it with ether. The structure of the purified product was confirmed by IR and NMR spectra and by elementary analysis.