Reductive ring cleavage of 1,3-disubstituted imidazolium iodides by sodium borohydride

The effect of NaBH4 on some simple, dissimilarly substituted imidazolium iodides with a benzyl substituent on 1 of the N atoms was investigated. In all cases, reductive ring cleavage occurred giving 2 isomers which were sepd. by their HCl salts. NaBH4 cleaves the imidazolium ring predominantly between the C-2 and the N atom bearing the benzyl group.