Triethylamine → Ethyl 3-(benzyloxy)-9-(2-(methylthio)ethyl)-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxylate

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Reaction Steps

To a solution of intermediate 20, ethyl 5-(benzyloxy)-2-(1-(2-hydroxyethoxy)-3-(methylthio)propyl)-6-oxo-1,6-dihydropyrimidine-4-carboxylate, (527 mg, 1.25 mmol) and Et3N (505 mg, 5 mmol) dissolved in 10 mL of CH2Cl2 was added a solution of CH3SO2Cl (288 mg, 2.5 mmol) dissolved in 2 mL of CH2Cl2. This was stirred for 20 hrs then concentrated. The crude product was purified by chromatography on silica gel, using 10:1 CH2Cl2:ether as eluent, to give the title compound 265 mg (52% yield). (500 MHz, CDCl3) δ ppm: 7.31–7.55 (5H, m) 5.30 (2H, s) 4.75 (1H, dd, J=3.66 Hz) 4.32–4.40 (2H, q, J=7.17 Hz) 4.13–4.30 (2H, m) 3.75–3.97 (2H, m) 2.20–2.84 (4H, m) 2.06 (3H, s) 1.32 (3H, t, J=7.17 Hz); LC/MS m/z 405 (M+H).

Provenance & Evidence