Water → 1190391-97-9

Participants

Reaction Steps

A solution of ethyl 2-bromo-5,6-dihydro-4H-cyclopenta[d][1,3]thiazole-4-carboxylate (4.92 g, 17.8 mmol) from step A was dissolved in 20 mL of methanol and added dropwise to a mixture of 4.25 mL (21.3 mmol) of a 5.0 N aqueous sodium hydroxide solution, 16 mL of water and 30 mL of methanol. After addition was complete the mixture was stirred for 2 h. The methanol was removed by evaporation and the pH of the remaining aqueous was adjusted to ˜2.5 with con. HCl. The mixture was saturated with solid sodium chloride and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over sodium sulfate and treated with activated charcoal overnight. The mixture was filtered and evaporated in vacuo. The residue was triturated with ethyl acetate and the solid filtered to afford the title compound (1.94 g). The mother liquor was evaporated and purified by MPLC using a gradient rising from 100% Hexanes to 100% ethyl acetate in Hexanes to afford an additional 0.82 g of the title compound as an off white solid (2.76 g in total, 62.0%). 1H NMR (500 MHz CDCl3) δ: 4.04 (m, 1H), 3.02-3.08 (m, 1H), 2.88-2.94 (m, 1H), 2.78-2.83 (m, 2H).

Provenance & Evidence