Acetic Anhydride → 1-[6-(4-Fluorophenyl)imidazo[2,1-b][1,3]oxazol-5-yl]ethanone

Participants

Reaction Conditions

Reaction Steps

To a mixture of 6-(4-fluorophenyl)-imidazo[2,1-b]oxazole (2675 g, 13.23 mol) and acetic anhydride (6.35 l) is added 160 ml of concentrated sulfuric acid. The reaction mixture is heated at 135° C. for 1.5 hours, then cooled to 80° C. with an ice bath. The reaction mixture is slowly quenched with 12.5 l of water. The solids are stirred overnight, filtered and air-dried. The solids are again suspended in water (15 l), stirred overnight, filtered, and washed with water (4 l) and then with toluene (4 l). The solid is dried under vacuum at 60° C., to give 2771 g (86%) of a dark brown solid; M.p.=173° C.; 300 MHz 1H NMR (DMSO-d6) δ 8.25-8.19 (m, 2H), 7.75-7.68 (m, 2H), 7.35-7.25 (m, 2H), 2.15 (s, 3H). LCMS: 245 [M+H].

Provenance & Evidence