Yield:140-98-7 93%

Reaction Conditions:

with zinc(II) chloride for 4 h;Heating / reflux;

Steps:

C

Reference Example C; Butyl maleurate; A mixture of 140 g of N-carbamylmaleimide (1 mole), 1.36 g of zinc chloride (0.01 moles) and 150 g of n-butanol (2 moles) was heated to reflux. After 4 hours, the mixture was poured into 400 mL of water and cooled to room temperature. The butyl maleurate was filtered, washed wilh water and dried to afford 200 g (93% yield). M.P.: 97°-9°C; 1H NMR (CDCl3): δ 10.6 (brs, 1 H), 8.2 (brs, 1 H), 6.3 (AB, 2 H), 5.9 (br s, 1 H), 4.2 (t, 2 H), 1.6 (m, 2 H), 1.4 (m, 2 H), 0.9 (t, 3 H); HPLC (20 to 40% CH3CN/H2O over 20 minutes, C8): Rt= 9.4 minutes.

References:

EP925283,2003,B1 Location in patent:Page/Page column 9