Non-symmetrical allenyl azines and their transformations leading to new heterocyclic skeletons

Abstract

The preparation of new non-symmetrical allenyl azines 5 with aliphatic and alicyclic substituents and their reactions are described. When aldazines 5 were refluxed in xylene formation of bicyclic products 7 was observed. Compounds 7 appeared as derivatives of isowithasomnine. Combined intra-intermolecular criss-cross cycloadditions of azines 5 afforded heterocyclic products 8 and 9 containing three fused five-membered rings. Structures of all new compounds were elucidated by 1 H and 13 C NMR, IR and MS measurements and in some cases by X-ray structure analysis.

Structure, synthesis and application of azines: a historical perspective

“…Preparation of new asymmetrical allenyl azines 101 with aliphatic and alicyclic substituents were described by Galeta et al in 2009. 37 The method was adopted by Zwierzak to prepare unsymmetrical azines. In this method, the rst step is protection of one of the nitrogen atoms of the hydrazine molecule by reaction with diethyl phosphite, forming diethyl hydrazidophosphate, 97.…”

The Criss‐Cross Cycloaddition: A Simple Access to Valuable Heterocycles and Polymers

“…On the other hand, separate but almost similar type of chemistry has fruitfully been reported by the same research group. Construction of the non‐symmetrical allenyl azines 215 having aliphatic or alicyclic substituents and their reactions by refluxing in xylene to give bicyclic products 220 has been revealed by the Potáček's research group ‐ the compounds 220 seemed as the derivatives of isowithasomnine Scheme 30 [40j] . Moreover, intra‐intermolecular CCC of azines 215 furnished the heterocycles 217 and 219 , possessing three fused five‐membered rings, has also been described.…”