Asymmetrical nitrogen-40;1 Geminal systems-261 N-chlorohydrazines3

The factors determining the kinetic and thermodynamic stabilities of N-chlorohydrazines are discussed. Acyclic N-chlorohydrazines exist only as trialkyldiazenium chlorides 3a,b. Chlorination of 2-acyl-1, 1-dimethylhydrazines 6a,b gave 1,4-diacyl-2,3-dimethylhexahydro-1,2,4,5-tetrazines 7a,b via hydrazyl radical intermediates, and chlorination of a 1-phenylpyrazolidin-5-one 8 gave phenylazoisovaleric esters 9a,b. Stable N-chlorohydrazines were obtained from bicyclic hydrazines; viz. the 2-chloro-1,2-diazabicyclo 2.2.2]octan-3-one 12 and 7-chloro-1,7-diazabicyclo2.2.1]heptane 16. The restricted inversion of N(7) in 16 and its 1-methyl quaternary salt 21 were observed in the ¹³C-NMR spectra. The acyclic N-chloro-hydrazinium salt 25 was isolated.