Chloroacetone → 5-Methyl-3-(2-oxopropyl)-1,3,4-oxadiazol-2(3H)-one

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Reaction Steps

To a solution of 5-methyl-3H-1,3,4-oxadiazol-2-one (5.509 g, 55.0 mmol) in MeOH (40 mL) is added 25 wt % NaOMe solution in methanol (12.7 mL, 58.8 mmol). The mixture is stirred at rt for 15 min and then concentrated in vacuo. The residue is added to a solution of tetrabutylammonium bromide (0.358 g, 1.08 mmol) and chloro-acetone (4.6 ml, 54.9 mmol) in CHCl3 (33 mL), and the mixture is heated to reflux for 5 h under N2. The mixture is cooled to rt and stirred overnight. The resulting slurry is filtered, and the filtrate is concentrated in vacuo. The residue is purified on a pad of silica gel, eluting with 2:1:1/heptane:EtOAc:DCM to afford 5-methyl-3-(2-oxo-propyl)-3H-1,3,4-oxadiazol-2-one (7.32 g, 86%) as a crystalline solid. MS: 157 (M+H); 1H NMR (300 MHz, CDCl3) δ 4.46 (s, 2H), 2.27 (s, 3H), 2.21 (s, 3H).

Provenance & Evidence