| Abstract
| - The reaction of 1-azido-3-chloropropane with variousGrignard reagents and subsequent treatmentwith anhydrous isopropylamine results in the formation of thecorresponding azimine. If the initialmagnesium−triazene complex is first hydrolyzed with Dowex resin andthen concentrated, theresultant linear triazene begins self-catalyzed cyclization to form thesix-membered-ring triazenesas the major product, with HCl as the byproduct. Addition of anamine, at reduced temperature,allows for the neutralization of the byproduct, HCl, which wouldotherwise react with the lineartriazene and the cyclic six-membered-ring triazene to form hydrolysisproducts. We have assignedthe trivial name of triazinines to this new class of cyclic triazenes.The hydrolytic decompositionof these compounds in mixed acetonitrile−aqueous bufferspredominantly forms 3-(alkylamino)-1-propanol and lesser amounts of the rearranged alcohol1-(alkylamino)-2-propanol and N-alkyl-2-propenamine. The rate of hydrolysis of 1-alkyltriazinines isapproximately equal to that of theanalogous 1,3,3-trialkyltriazenes, about three times slower than thatof the analogous 1-alkyltriazolines, and varies in the order ethyl > butyl > 3,3-diethoxypropyl >benzyl. As was true for othertriazenes, the mechanism of the decomposition was found to be specificacid-catalyzed (A1), involvingrapid reversible protonation followed by rate-limiting formation of a3-(alkylamino)propyldiazoniumion. The slopes of the log kobs versus pHplots were near −1.0. The solvent deuterium isotopeeffect,kH2O/kD2O,was in all cases <1.0 and ranges from 0.82 for 1-benzyltriazinine to0.89 for1-ethyltriazinine. The activation parameters of the proteolyticdecomposition of a series, 1-ethyltriazinine, 1-ethyltriazoline, 1,3,3-triethyltriazene, and1-ethyl-3-methyltriazene, had similar valuesfor ΔH⧧ (+9 → 12 kcal/mol) andΔS⧧ (+7 → 15 eu),respectively.
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