Reactions of group IV organometallic compounds. Part XIV. Anomalous cyclization products from the reaction of heptamethyldisilazane with phenyl isocyanate at elevated temperatures

Abstract

The reaction between heptamethyldisilazane and excess of phenyl isocyanate at 150° gave two abnormal products, 4-methylimino-1,3,5-triphenylhexahydro-1,3,5-triazine-2,6-dione (III)(56%) and 1,3,5-triphenyl-2,4,6-tri-(phenylimino)hexahydro-1,3,5-triazine (IV)(43%). Formation of (III) was ascribed to a cycloaddition of methylphenylcarbodi-imide with two molecules of phenyl isocyanate; that of (IV) could be explained by the catalysed trimerization of the intermediate diphenylcarbodi-imide derived through a decarboxylation reaction.