Russian Chemical Bulletin, International Edition, Vol. 52, No. 1, pp. 192—197
Цитата:
Synthesis of monosubstituted ureas 2a—g (general procedure). An aqueous solution of the corresponding amino acid (dipeptide or amino alcohol) (0.05 mol) was heated to boiling and then KOCN (4.5 g, 0.052 mol) was added in five portions to the gently refluxing solution. After the addition of a total amount of KOCN, the reaction mixture was refluxed for 20 min (in the case of dipeptide, for 30 min), cooled to 20 °C, and treated
with an equimolar amount (4.5 mL) of concentrated HCl to pH 1. Then the reaction mixture was kept at 20 °C for 7 h and crystals of compounds 2a—e that precipitated were filtered off. In the case of 2f,g, the reaction mixture was concentrated to dryness in vacuo, MeOH (20 mL) was added, and a precipitate of KCl was filtered off. The filtrate was concentrated in vacuo, the oily residue was triturated with a 1 : 2 MeOH—Et2O mixture(15 mL), and products 2f,g that formed were filtered off.
Ureidoethanoic acid (2a). The yield was 95%, m.p. 173—175 °C (cf. lit. data17: m.p. 165 °C).

2 rombach
Спасибо за методу - аккурат сейчас выпадают хорошо сформованные кристаллы гидантоиновой к-ты.
С меня пиво.