Abstract: Objective The reactions of quaternary ammoniumsalts of N-heterocycles were investigated. Methods The rearrangement reactions of N-heterocycles might be performed if the N-ylide intermediates can be generated. In compounds containing a β-hydrogen atom, Hofmann elimination may compete and in many cases provides the major product. We tried N-cyanomethyl-N-methylpiperidine bromide and N-cyanomethyl-N-methyltropinone bromide which were treated with sodium hydride. Results The quaternary ammonium salt N-cyanomethyl-N-methylpiperidine bromide furnished the rearrangement reactions products 2-piperidinyl-2-cyanoyl-propionaldehyde and N-cyanomethyl-atropine bromide gave Hofmann elimination product 2-piperidinyl-2-cyanoyl-propionaldehyde. Conclusion Thus we have explored the reaction quaternary ammoniumsalts of N-heterocycles with sodium hydride. Some of them performed Hofmann elimination reactions and some of them underwent rearrangement reactions. N-methylpiperidine and tropinone derivatives were tested. N-methylpiperidine derivative react with sodium borohydride to performed rearrangement reactions. Tropinone derivatives performed Hofmann elimination reaction and cyclize to produce 7.

Key words: quaternary ammoniumsalts, piperidine, rearrangement reactions