Synthesis of selenium-containing para-phenylenediamines: novel antidegradants for natural rubber

Abstract

The synthesis of novel N,N′-substituted para-phenylenediamines bearing side-chains containing one or two monoselenide linkages is described. Reductive alkylation of para-phenylenediamines with oxoselenides using sodium cyanoborohydride in methanol gives good to high yields of these compounds. Compounds containing one selenide linkage react with 3 mol equivalents of ozone, and those containing two selenide linkages react with 4 mol equivalents of ozone, compared to only 2 mol equivalents of ozone in the case of N-isopropyl-N′-phenyl-p-phenylenediamine. Synthetic routes to the oxoselenides required as precursors are described.