519032-08-7

518047-98-8

762-42-5

519032-08-7

The general procedure for the synthesis of methyl 2-(2-(benzyloxycarbonylamino)propan-2-yl)-5-hydroxy-6-oxo-1,6-dihydropyrimidine-4-carboxylate from benzyl [2-amino-2-(oximido)-1,1-dimethylethyl]carbamate and dimethyl ethynedicarboxylate was as follows: benzyl 2-amino-2-(hydroxyimino)-1,1-dimethylethyl carbamate ( 2.0 g, 8.0 mmol) was dissolved in 30 mL of methanol and dimethyl acetylenedicarboxylate (DMAD, 1.1 mL, 9.0 mmol) was added slowly. The reaction mixture was stirred at room temperature for 2 h. Subsequently, a white oil was obtained by concentration under reduced pressure. This oily substance was mixed with 80 mL of xylene and stirred at 90 °C for 2 hours, then warmed up to 120 °C for 2 hours and finally refluxed under nitrogen protection for 12 hours. After completion of the reaction, the mixture was concentrated to give the crude product. The crude product was purified by recrystallization with 2 mL of methanol and 10 mL of tert-butyl methyl ether to afford the target compound 5 as a yellow solid (1.7 g, 58% yield). Its 1H-NMR (DMSO-d6) data were as follows: δ 7.35 (m, 5H), 5.00 (s, 2H), 3.83 (s, 3H), 1.48 (s, 6H); ESI-MS m/z 360 (M-), 384 (M + Na+).