Methyl bromoacetate → 5-Benzyloxy-1-methoxycarbonylmethyl-2-methylsulfanyl-6-oxo-1,6-dihydro-pyrimidine-4-carboxylic acid ethyl ester

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Reaktionsschritte

A solution of intermediate 1, 5-benzyloxy-2-methylsulfanyl-6-oxo-1,6-dihydro-pyrimidine-4-carboxylic acid ethyl ester, (2.00 g, 6.24 mmol) in dry tetrahydrofuran (100 ml) was treated with methyl bromoacetate (1.05 g, 6.86 mmol) followed by powdered calcium hydride (0.59 g, 14.0 mmol) and the resulting mixture was heated under reflux for 18 h. The reaction mixture was then cooled, quenched by the addition of a few drops of acetic acid and concentrated in vacuo. The residue was then diluted with ethyl acetate, washed successively with saturated sodium bicarbonate and brine then dried over anhydrous magnesium sulfate. Evaporation of the solvent followed by chromatography on silica gel (elution toluene/ethyl acetate 95:5) gave 1.10 g (45% yield) of the title ester as a clear oil. 1HNMR 400 MHz (CDCl3) δ (ppm): 1.31 (3H, t, J=7.2 Hz, CH3), 2.60 (3H, s, SCH3), 3.80 (3H, s, OCH3), 4.33 (2H, q, J=7.2 Hz, OCH2), 4.84 (2H, s, NCH2), 5.21 (2H, s, OCH2), 7.3–7.5 (5H, m, aromatics). HRMS (FAB POS) calculated for C18H21N2O6S [M+H+]: 393.112033. found: 393.112070.

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