Study On The Reaction Of Allenic Acid Esters And β-(2- Haloaryl)-Heterrocyclic Ketene Aminals

Allenes, which are endowed with features by the presence of the cumulated diene structural unit, show unique reactivity in organic synthesis. Different kinds of substituent group including aryl, alkyl, allyl, cyano, acetyl ethoxycarbonyl and methoxycarbonyl is successfully introduced into both ends of the allenes, which provides unlimited opportunities for diversity of methodology of organic synthesis.β-(2-Haloaryl)-heterocyclic ketene aminals are good synthons in the form of C-C bond and C-N bond because of its high reactivity.β-(2-Haloaryl)-heterocyclic ketene aminals are powerful and versatile intermediates for the synthesis of a wide variety of new heterocycles and fused heterocycles.This thesis focus on building new frame work of [1, 8]naphthyridine,twenty five new imidazo(pyrido)[1,2-a]pyridines and twenty three imidazo(pyrido)[3,2,1-ij]- [1,8]naphthyridines compounds were synthesized via the reaction of allenic acid esters and heterocyclic ketene aminals.In the first chapter, allenes and polarized heterocyclic ketene aminals as very useful synthons in organic synthesis were reviewed in brief. In the second chapter, imidazo(pyrido)[1,2-a]pyridines and imidazo(pyrido)[3,2,1-ij][1,8]naphthyridines derivatives unreported in the literatures have been synthesised withβ-(2-haloaryl)- heterocyclic ketene aminals and allenic esters reactions in the presence of DABCO and K₂CO₃ as catalyst. The reaction conditions including solvent, catalyst and molar ratio were also investigated. These reactions were very mild, convenient and effective.In this reaction, nine different active sites were involved; three new bonds and two new rings were constructed with all reactants which efficiently utilized via a sequence of Knoevenagel condensation, aza-ene reaction, cyclization and intramolecular nucleophilic substitution reactions. It fully reflects the"atom economy" in this reaction.The structures of all the target compounds were confirmed by IR, 1H NMR, 13C NMR, and HRMS, and the plausible mechanism was also presented. The unambiguous molecular structure of 4a and 6g were determined by X-ray diffraction analysis.