1: 1-benzyl-5-hydroxy-hydantoin With thionyl chloride in toluene T=90°C; 4 h; 2: ethanol T=80 - 82°C; 5 h;

1: phenyl-methylurea; formyl formic acid; glyoxylic acid monohydrate With acetic acid in water T=100°C; 2 h; 2: orthoformic acid triethyl ester With sulfuric acid in ethanol T=80°C; 1 h; 3: in hexane; ethyl acetate T=3 - 25°C; 11 h;