ChemInform Abstract: Reactivity of Conjugated Azoalkenes Towards α-Amino Acid Ethyl Esters

The synthesis of Z- and E-arylhydrazones by 1,4-conjugate addition of glycine, L-alanine and L-tyrosine ethyl esters to phenylazostilbene 1, p-nitrophenylazostilbene 2 and p-nitrophenylazocyclohexene 3 is described. Optically active N-functionalized 2-aminocyclohexanones 22–26 are obtained by TiCl3 catalysed hydrolysis of the corresponding hydrazones. However, they have been shown to be unstable, as they undergo easy oxidation by air. X-Ray analysis of the phenylhydrazone 8a in the Z configuration is also reported.