Ethyl 2-Cyano-2-methylpropionate → Ethyl 2-carbamothioyl-2,2-dimethylacetate

Participants

Reaction Steps

A mixture of diphenyldithiophosphonic acid (ALFAAESAR, 1.42 g, 5.67 mmol) and 2-cyano-2-methylpropionic acid ethyl ester (ABCR, 0.412 mL, 2.83 mmol) in isopropanol (30 mL) was heated under reflux for 4 h. Reaction mixture was cooled to room temperature and a precipitate was formed. Reaction flask was placed in the freezer for 1 h. Reaction mixture was filtered and filtrate was concentrated. Residue was taken up in DCM (100 mL) and washed with water (20 mL), 1N NaOH (20 mL), saturated NaHCO3 (20 mL) and dried over sodium sulfate and concentrated. The resulting oil was loaded on a 25 g silica cartridge and eluted with linear gradient 0-50% hexane-ethyl acetate to yield the title compound (110 mg, 0.628 mmol, 22.2% yield). Another impure batch was loaded on a 10 g silica cartridge and eluted with linear gradient 0-50% hexane-ethyl acetate to recover the title compound (120 mg, 0.685 mmol, 24.17% yield). Total yield: (230 mg, 1.313 mmol, 46.32%). 1H NMR (300 MHz, DMSO-d6) δ ppm: 9.70 (br s, 1H), 8.86 (br s, 1H), 4.05 (q, 2H), 1.39 (s, 6H), 1.15 (t, 3H). [ES+MS] m/z 176 (MH+).

Provenance & Evidence