m-Chloroperbenzoic acid → 5-Bromo-2-methylpyridin-1-ium-1-olate

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-bromo-2-methylpyridine (1.0 eq.) in chloroform (0.38 M) was added 77% meta-chloroperbenzoic acid (mCPBA) (4.0 eq.) and heated at 60° C. for 20 hours. After cooling to room temperature, Ca(OH)2 (5.3 eq.) was added, and the resulting precipitate was stirred for 30 minutes. The precipitate was filtered and washed with 3:1 CHCl3/methanol. The filtrate was concentrated en vacuo to give a solid, which was stirred in 30% ethyl acetate in hexane and filtered to give the desired N-oxide. The filtrate was concentrated en vacuo, and the residue was purified by a COMBIFLASH® system (ISCO) using 0-100% ethyl acetate in hexane to give more of the desired N-oxide. The two batches were combined and carried onto the next step.

Provenance & Evidence