Ammonia → 6-Benzyloxy-2,5-dioxo-1,2,3,5-tetrahydro-imidazo[1,2-a]pyrimidine-7-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

A solution of intermediate 3, 5-benzyloxy-2-methanesulfonyl-1-methoxycarbonylmethyl-6-oxo-1,6-dihydro-pyrimidine-4-carboxylic acid ethyl ester, (1.10 g, 2.59 mmol) in acetonitrile (20 ml) was treated with a freshly prepared solution of ammonia in acetonitrile (20 ml) and the resulting mixture stirred at 22° C. for 2 h. The reaction was monitored by LC/MS and rapid formation of the amino intermediate followed by cyclization was observed. The solvent was then evaporated in vacuo and the residue was diluted with ethyl acetate, washed successively with saturated sodium bicarbonate and brine then dried over anhydrous magnesium sulfate. Evaporation of the solvent followed by recrystallization of the solid residue from ethyl acetate/hexane gave 0.770 g (82% yield) of the title ester as white crystals; mp 196° C. 1HNMR 400 MHz (CDCl3) δ (ppm): 1.33 (3H, t, J=7.2 Hz, CH3), 4.39 (2H, q, J=7.2 Hz, OCH2), 4.57 (2H, s, CH2), 5.24 (2H, s, OCH2), 7.3–7.55 (5H, m, aromatics), 9.6 (1H, broad, NH). Anal. Calcd for C16H15N3O5: C, 58.35; H, 4.59; N, 12.76. Found: C, 57.99; H, 4.27, N, 12.62.

Provenance & Evidence