Benzyl Bromide → Ethyl 3-(benzyloxy)-9,9-dimethyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxylate

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Reaction Steps

To a stirred solution of ethyl 3-hydroxy-9,9-dimethyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxylate, (2.68 g, 10 mmol) and benzyl bromide (1.43 mL, 12 mmol) in DMF (40 mL) was added K2CO3 (2.07 g, 20 mmol). After stirring 48 h at ambient temperature, the reaction mixture was diluted with ether (100 mL), then washed with water (3×30 mL) and brine (20 mL). The organic layer was dried (Na2SO4/activated carbon), filtered and concentrated to give a yellow solid. Trituration with hexanes/ether (9:1) afforded the title compound as an off-white solid (2.79 g, 78% yield). 1H NMR (500 MHz, CDCl3) δ ppm: 7.48-7.45 (2H, m), 7.37-7.30 (3H, m), 5.25 (2H, s), 4.33 (2H, q, J=7.3 Hz), 4.05-3.99 (4H, m), 1.62 (6H, s), 1.29 (3H, t, J=7.3 Hz). HRMS (M+H) calcd for C19H23N2O5: 359.1607; found: 359.1611. Anal calcd for C19H22N2O5: C, 63.67; H, 6.18; N, 7.81; found: C, 63.63; H, 6.16; N, 7.78.

Provenance & Evidence