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

3-Oxidopyraziniums are accessed from 2(1H)-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.1-(4-methoxybenzyl)-5,6-dimethyl-3-oxidopyrazinium (C14H16N2O2) dimerises at room temperature, forming a tetracyclic alcohol C28H34N4O5, the structure of which was elucidated using spectroscopic and X-ray analyses.