Water → 1190391-97-9

Participants

Reaction Steps

A solution of the product from step A (4.92 g, 17.82 mmol) was dissolved in methanol (20 mL) and added dropwise to a mixture of of 5 N NaOH (4.25 mL, 21.25 mmol), water (16 mL) and methanol (30 mL). 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 conc. HCl. The mixture was saturated with solid NaCl and extracted with EtOAc (×3); combined EtOAc layers washed with sat. NaCl, dried over Na2SO4 and treated with activated charcoal overnight. The filtered mixture was evaporated. The residue was triturated with EtOAc, and the solid filtered to give 1.94 g of the desired product. The mother liquors were evaporated and purified by MPLC using a gradient rising from 100% Hexanes to 100% EtOAc in Hexanes to give a further 0.82 g of the title product (2.76 g in total, 62%) as an off white solid. 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