Diphenyl carbonate → Phenyl (5-acetyl-4-methyl-1,3-thiazol-2-yl)carbamate

Participants

Reaction Steps

In a round-bottom flask, NaH 60% dispersion in mineral oil (3.07 g, 77 mmol) was washed 2× with hexane and suspended in DMF. Then 2-amino-5-acetyl-4-methyl-thiazole (10.0 g, 64 mmol) was added and stirred while cooling in an ice bath. Stirring continued until the NaH was consumed. Diphenyl carbonate (34 g, 160 mmol) was added while cooling and after the addition was complete the reaction mixture was stirred for an additional 30 minutes at room temperature. The DMF was removed on a rotary evaporator (high vacuum, 40° C.) to yield a brown residue. This residue was dissolved in 1 L of CHCl3 and washed successively with 2 L of 0.5N HCl, 2×1 L of water, and finally by 1 L of brine. The aqueous portions were back extracted twice with 300 ml of CHCl3. The combined organic fractions were dried over anhydrous sodium sulfate, filtered and concentrated on a rotary evaporator to give a white solid. This was chromatographed on silica (15%-70% EtOAc/hexane) to give 15 g of the desired carbamate as a white solid. Mp 180-182° C. 1H NMR (300 MHz, CDCl3) δ 11.42 (bs, 1H), 7.47-7.40 (m, 2H), 7.33-7.27 (m, 1H), 7.22-7.18 (m, 2H), 2.72 (s, 3H), 2.50 (s, 3H). ESI MS: (M+H)+=277.1. Anal. Calcd for C13H12N2O3S: C, 56.51; H, 4.39; N, 10.14; S, 11.60. Found: C, 56.42; H, 4.31; N, 10.11; S, 11.74.

Provenance & Evidence