Importance of repulsion of lone electron pairs in the enhanced reactivity of 1,8-naphthyridine and the large α-effect of hydrazine in the aminolyses of p-toluenesulfonyl chloride

Article abstract of DOI:10.1139/v86-196

The rates of aminolyses of p-toluenesulfonyl chloride with primary and tertiary amines have been determined both in acetonitrile and in ethanol.The Broensted plots of log k_rel again pK_a' values fo amines (except hydrazine and 1,8-naphthyridine in acetonitrile) gave a good correlation when the aminolyses were carried out in acetonitrile.In ethanol, however, although Broensted plots with all tertiary amines show a good correlation, less basic hydrazine shows a higher reactivity than n-butylamine.The abnormal rate enhancement found with hydrazine is undoubtedly due to the α-effect, while with 1,8-naphthyridine in acetonitrile is considered to be due to the repulsion of two lone electron pairs on the two nitrogen atoms in 1,8-naphthyridine.