反应详情

A mixture of intermediate 26, ethyl 3-(benzyloxy)-9,9-dimethyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxylate, (2.93 g, 8.2 mmol) and LiOH.H2O (0.84 g, 20 mmol) in 4:1 ethanol/tetrahydrofuran (50 mL) was stirred for 2 h at ambient temperature then concentrated under vacuum. The resulting yellow residue was treated with 1N HCl (25 mL) providing a precipitate that was filtered and dried under vacuum to yield the title compound as a white powder (2.68 g, 99% yield). 1H NMR (500 MHz, CDCl3) δ ppm: 7.54–7.48 (2H, m), 7.37–7.27 (3H, m), 5.44 (2H, s), 4.05–3.93 (4H, m), 1.60 (6H, s).). HRMS (M+H) calcd for C17H19N2O5: 331.1294; found: 331.1308. Anal calcd for C17H18N2O5: C, 61.81; H, 5.49; N, 8.48; found: C, 61.84; H, 5.36; N, 8.25.

1. concentrationthen concentrated under vacuum
2. additionThe resulting yellow residue was treated with 1N HCl (25 mL)
3. customproviding a precipitate that
4. filtrationwas filtered
5. customdried under vacuum