Studies On The Synthesis Of New Spiroheterocycles Through 1,3-Dipolar Cycloaddition Reaction

This paper focuses on the synthesis of novel series of spiroheterocyclic compounds via 1,3-dipolar cycloaddition reactions.Spiroheterocyclic compounds were a kind of special spirocyclic compounds with nitrogen, sulfur, oxygen, etc. Because of particular structure, it has good stereoselectivity and highly pronounced biological properties. Attracted more and more scientists' attention, it is widely used in the field of medicine, pesticide, dyestuff, material and so on. The 1,3-dipolar cycloaddition is considered to be one of the most powerful tool for the construction of spirocyclic compound especially five-membered heterocyclic compounds.In this paper, about forty novel spiroheterocyclic compounds were synthesized by 1,3-dipolar cycloaddition reactions of azomethine ylide which generated in situ from sarcosine and isatin and self-synthesized dipolarphiles with exo-cyclic double bond. It can be described into two portions as followed:The compound 3-aryl-5-arylmethylenespiro[indole-3',2-[1,3]thiazolane]-2'(1H),4--dione was synthesized by the addition of mercaptoacetic acid and the imine compound synthesized by the condensation of isatin and aromatic amine. A series of 27 novel spiroheterocyclic compounds were synthesized by 1,3-dipolar cycloaddition reactions of self-synthesized dipolarphiles with exocyclic double bond and azomethine ylide derived from isatin and sarcosine by a decarboxylative route. And improve the experimental conditions, improve the yield. Structures of novel compounds were determined by IR,1H NMR and elemental analysis. The regio and stereochemistry of these 1,3-dipolar cycloaddition reactions was established by X-ray single crystal analyses.The compound 3-phenyl-2-thioxothiazolidin-4-one was synthesized by the addition of phenyl isothiocyanate and mercaptoacetic acid. Then these thioxothiazolidin reacted with appropriate aryl aldehydes to give the compound 5-arylmethylene-3-phenyl-2-thioxothiazolidin-4-one with two exocyclic double bond. A series of 16 novel new dispiropyrrolidine spiroheterocyclic compounds were synthesized by 1,3-dipolar cycloaddition reactions of self-synthesized dipolarphiles with exocyclic double bond and azomethine ylide derived from isatin and sarcosine. The compounds were determined by IR,1HNMR and elemental analysis. The regio and stereochemistry of these 1,3-dipolar cycloaddition reactions was established by X-ray single crystal analyses.