Nitrogen-15 studies of the mechanisms of acetolyses of hexamethylenetetramine and 3,7-diacetyl-1,3,5,7-tetraazabicyclo[3.3.1]nonane (DAPT)

¹⁵N₄]-Hexamethylenetetramine (Hexamine), and ¹⁵N₄]-3,7-diacetyl-1,3,5,7-tetraazabicyclo3.3.1]nonane(DAPT) have been prepared starting from ¹⁵NH₃. Synthetic acetolysis reactions were performed using mixtures of pure ¹⁵N₄]- and ¹⁴N₄]-compounds and the destination of the nitrogen isotopes in the products was determined mass spectrometrically. The results show that relatively little isotopic mixing occurs in the acetolysis of hexamine to DAPT though the formation of some products with isotopic composition ¹⁴N₃¹⁵N₁] and ¹⁴N₁¹⁵N₃] indicates limited ring cleavage. However the more severe conditions used in the formation of 1,3,5-triacetyl-1,3,5-triazacyclohexane (TRAT) give rise to considerable isotopic scrambling. The acetolysis of DAPT to give 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane occurs by selective cleavage of the methylene bridge.