Diethyl Oxalate → HCID 135980894, compound

Participants

Reaction Conditions

Reaction Steps

A solution of diethyl oxalate (27.2 g, 0.186 mol) and methyl methoxyacetate (19.38 g, 0.186 mol) in dry tetrahydrofuran (250 ml) was treated at 22° C. with sodium hydride (8.15 g of a 60% dispersion in mineral oil, 0.203 mol) and the resulting mixture was stirred at 22° C. for 18 h. The tetrahydrofuran was then evaporated under reduced pressure and the residual orange syrup was dissolved in a solution of sodium ethoxide (0.189 mol, prepared from 4.35 g of sodium) in ethanol (300 ml). Then powdered 2-methyl-2-thiopseudourea sulfate (25.9 g, 0.093 mol) was added and the resulting mixture was stirred at 22° C. for 1 h and then heated at 60° C. for 2 h. Acetic acid (5 ml) was then added to the gel like reaction mixture and the ethanol was evaporated under reduced pressure. The residual paste was partitioned between water and dichloromethane and the aqueous phase was extracted five times with dichloromethane. The combined organic phases were washed with brine and dried over anhydrous magnesium sulfate. Evaporation of the solvent gave a semi-solid residue which was triturated with ethyl acetate (100 ml). The light yellow solid formed was collected (10.02 g) and chromatographed on silica gel. Elution with a mixture of dichloromethane and ethanol (98:2) gave 6.02 g (13% yield) of the title ester as white needles; mp 171–173° C. (ethyl acetate). 1HNMR 400 MHz (CDCl3) δ (ppm): 1.42 (3H, t, J=7.1 Hz, CH3), 2.62 (3H, s, SCH3), 3.99 (3H, s, OCH3), 4.43 (2H, q, J=7.1 Hz, CH2), 11.8 (1H, broad s, NH). Anal. Calcd for C9H12N2O4S: C 44.25; H, 4.95; N, 11.47. Found: C 44.22; H, 5.04; N, 11.46.

Provenance & Evidence