Diethyl Oxalate → HCID 135848644, compound

Participants

Reaction Conditions

Reaction Steps

Diethyl oxalate (2.77 g, 19.0 mmol) and ethyl benzyloxyacetate (3.69 g, 19.0 mmol) in dry tetrahydrofuran (30 ml) were treated at 22° C. with sodium hydride (0.83 g of a 60% dispersion in mineral oil, 20.9 mmol) followed by ethanol (10 μl) and the resulting mixture was stirred at 22° C. for 18 h. The tetrahydrofuran was evaporated under reduced pressure to give an orange syrup. A mixture of intermediate 3, 2-(2-(methylthio)ethoxy)acetamidine hydrochloride salt, (3.50 g, 19.0 mmol) in a solution of sodium ethoxide (9.5 mmol, prepared from 0.22 g of sodium in ethanol 25 ml) was then added all at once to the above adduct and the resulting mixture heated at 60° C. for 3 h. Acetic acid (2 ml) was added and the ethanol was evaporated under reduced pressure. The residue was diluted with ethyl acetate washed successively with saturated sodium bicarbonate and brine, then dried over anhydrous magnesium sulfate and concentrated under reduced pressure. Chromatography on silica gel (elution with a gradient of ethyl acetate 20–30% in toluene) gave 0.728 g (10% yield) of the title ester as a clear oil. 1HNMR 400 MHz (CDCl3) δ (ppm): 1.33 (3H, t, J=7.1 Hz, CH3), 2.18 (3H, s, SCH3), 2.78 (2H, t, J=6.0 Hz, CH2), 3.78 (2H, t, J=6.0 Hz, CH2), 4.36 (2H, q, J=7.1 Hz, OCH2), 4.54 (2H, s, OCH2), 5.35 (2H, s, OCH2), 7.37 (3H, m, aromatics), 7.48 (2H, m, aromatics). HRMS (ESI+) calculated for C18H23N2O5S [M+H+]: 379.1328. found: 379.1314.

Provenance & Evidence