Ethyl 3-benzyloxy-9-methyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxylate → Ethyl 3-hydroxy-9-methyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxylate

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Reaction Steps

Hydrogenolysis of intermediate 14, ethyl 3-benzyloxy-9-methyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxylate, (0.610 g, 1.77 mmol) in a mixture of ethyl acetate (75 ml) and ethanol (75 ml) at 25° C. over 10% palladium on activated carbon (0.20 g) under 1 atm of hydrogen for 2 h gave 0.430 g (95% yield) of the title ester as white crystals; mp 119–121° C. (ethyl acetate-hexane). 1HNMR 400 MHz (CDCl3) δ ppm: 1.46 (3H, t, J=7.1 Hz, CH3), 1.67 (3H, d, J=6.6 Hz, CH3), 3.90 (2H, m, CH2), 4.13–4.32 (2H 4.51 (2H, m, OCH2), 4.70 (1H, q, J=6.6 Hz, CH), 10.7 (1H, broad, OH). Anal. Calcd for C11H14N2O5: C, 51.96; H, 5.55; N, 11.01. Found: C, 51.60; H, 5.61; N, 10.70.

Provenance & Evidence