N-bromobutanimide → 5-(4-Bromo-3-(pyridin-2-yl)isoxazol-5-yl)-3-p-tolyl-1,2,4-oxadiazole

Participants

Reaction Steps

A solution of 5-(3-(pyridin-2-yl)isoxazol-5-yl)-3-p-tolyl-1,2,4-oxadiazole (655 mg, 2.15 mmol), N-bromosuccinimide (536 mg, 3.01 mmol), and PdOAc2 (97 mg, 0.430 mmol) in acetonitrile (12 mL) was heated to 120° C. via microwave for 30 minutes. The reaction was repeated three additional times on a similar scale, and the contents of each reaction tube were combined and filtered. The solid was collected, triturated with methanol (10 mL), and collected by vacuum filtration to give 5-(4-bromo-3-(pyridin-2-yl)isoxazol-5-yl)-3-p-tolyl-1,2,4-oxadiazole (3.24 g, 87% yield). The compound had an HPLC retention time=3.96 minutes (YMC-Combi 4.6×50 mm S-5 ODS column) eluting with 10-90% aqueous methanol+0.2% phosphoric acid over a 4 minute gradient. MS: (M+H)=385+. 1H NMR (400 MHz, CDCl3) δ ppm 2.46 (s, 3H), 7.35 (d, J=8.03 Hz, 2H), 7.49 (ddd, J=7.65, 4.89, 1.00 Hz, 1H), 7.91 (td, J=7.78, 1.76 Hz, 1H), 8.03 (d, J=7.78 Hz, 1H), 8.12 (d, J=8.28 Hz, 2H), and 8.86 (d, J=4.77 Hz, 1H).

Provenance & Evidence