Thermal dealkylation of 2,4-bis(alkylamino)-6-chloro-s-triazines. Effect of ring size on formation of alicyclic olefins. Part 3

Abstract

The thermal dealkylation of 2,4-bis-(N-1-methylcycloalkylamino)-6-chloro-s-triazines and 2,4-bis-(N-cycloalkyl-methylamino)-6-chloro-s-triazines containing five-, six-, and seven-membered rings gave mixtures of olefinic products in which endocyclic isomers predominated. In the case of 1-methylcycloalkyl derivatives this was attributed to the influence of thermodynamic and statistical as well as entropy effects. Steric effects were considered to be similar, since the transition states for both isomers could have planar arrangements, anticipating a boat conformation for the cyclohexyl derivative under the reaction conditions. The predominance of endocyclic isomers in the case of cycloalkylmethyl substrates as well as the presence of cycloalkylmethyl chloride in the products could not be explained by an E_i mechanism. Possible mechanisms for this dealkylation are discussed.