1,3-Dialkyl-3-acyltriazenes: Products and Rates of Decomposition in Acidic and Neutral Solutions

Article abstract of DOI:10.1021/jo00028a047

The products and mechanism of hydrolytic decomposition of a series of 1,,3-dialkyl-3-acyltriazenes were studied in both acidic and neutral buffers.In the acidic region, the products are alkyl alcohols derived from the N(1) alkyl group and amides derived from the intact N(3) portion of the molecule.The solvent deuterium isotope effect (k_H2O/k_D2O)) is less than 1.0.The mechanism is specific acid catalyzed, involving rapid reversible protonation of the 3-acyl group followed by scision of the N(2)-N(3) bond to generate an amide and an alkyl diazonium ion.The (2-hydroxyethyl)diazonium ion gives ethylene glycol and acetaldehyde, while the (2-chloroethyl)diazonium ion yields 2-chloroethanol.In the neutral region, the products are similar to those found in acidic buffers, alkyl alcohols, and amides.At this pH the (2-chloroethyl)diazonium ion produces ethylene glycol and acetaldehyde in addition to 2-chloroethanol.The solvent deuterium isotope effect (k_H2O/k_D2O) is greater than 1.0.The mechanism involves unimolecular heterolylsis of the N(2)-N(3) bond to form an amide anion and an alkyldiazonium ion.The methyldiazonium ion leads to incorporation of deuterium in the methyl group of the products, indicating the existence of an equilibrium between the metastable methyldiazonium ion and diazomethane.