The cycloaddition chemistry of 3-oxidopyraziniums. Dimerisation of 3-oxido-1-(4-methoxybenzyl)-5,6-dimethylpyrazinium

Abstract

3-Oxidopyraziniums are accessed from 2(1 H )-pyrazinones via N-alkylation and then exposure of the resulting pyrazinium salts to mild base at room temperature. 3-Oxidopyraziniums react with acrylates in a 1,3-dipolar cyclisation producing 3,8-diazabicyclo[3.2.1]octanes. 3-Oxido-1-(4-methoxybenzyl)-5,6-dimethylpyrazinium (C 14 H 16 N 2 O 2 ) dimerises at room temperature, forming a tetracyclic alcohol C 28 H 34 N 4 O 5 , the structure of which was elucidated using spectroscopic and X-ray analyses.