Synthesis and structure of polycyclic O-containing systems based on diarylmethylidenepiperidones (cyclanones)

Abstract

In this work, the interaction of diarylmethylidene piperidones with acetylacetone and acetoacetic ester has been studied. It has been shown that the transition to piperidone in the basis of dienone does not allow the selective synthesis of products. It has been found that the direction of the reaction with 1,3-C,C-dinucleophilic reagents is influenced by the nature of peripheral ylidene substituents, which allows targeted synthesis of O-heterocyclization products (hexahydropyranopyridines) by introducing an NO2 group into the arylmethylidene fragment. Previously unknown substituted deca(octa)hydro(xanthenes)cyclopentachromenes have been synthesized. It has been established that the interaction of diarylmethylidenecyclanones with cyclohexa(penta)ne under conditions of mild basic catalysis (piperidine) proceeds nonselectively, the size of the cycle in the base of the initial substrate plays an important role, and the reaction products are always a mixture of substances (two or more). Based on the experimental data obtained, a scheme has been proposed for the formation of hydroxanthene and hydrocyclopentachromene fragments of the resulting products. It has been found that, while maintaining the general direction of the reaction, the determining role in the structure of the products is played by the size of the cycle (С5,С6) in the basis of the initial substrates. Six-membered fused fragments promote enolization and intramolecular O-heterocyclization of 1,5-diketone with the formation of polycyclic systems. The composition and structure of the synthesized compounds have been confirmed by elemental analysis, IR and one-dimensional, two-dimensional NMR spectroscopy.