The Synthesis Of Novel Nitrogenous Heterocyclic Compounds By The1,3-Dipolar Cycloaddition Reaction Of Nitrile Oxides

The paper focus on the synthesi s of a number of novel heterocyclic compounds by the1,3-dipolar cycloaddition reaction of nitrile oxides.We synthe sized seven sy stem s of different dipolarophiles.At the same time,we synthe sized2,6-dichloro-benzaldehyde N-oxide as one of the1,3-dipoles which is relativelv stabile in air.Several Clas ses of heterocycle compounds which have not been reported in the literature were synthesized by the1,3-dipolar cycloaddition of dipolarphiles with exo-cyclic double bonds and2,6-dichlorobenzonitrile oxide.1. The1,3-dipolar cycloaddition of nitrile oxide and (2-aryl--methylidene-2,3-dihydro-1H-pyrrolizin-1-ones,(7E)-7-aryl-6,7-dihydro-indolizin-8(5H)-one)afforded16novel spiroisoxazole derivatives.2.26novel Oxadiazole derivatives were synthesized by the1,3-dipolar cycloaddition of2,6-dichlorobenzonitrile oxide and((2Z)-2-aryl-5,6-dihydroimi dazo[2,1-b)][1,3]thi azol-3(2H)-one,(2Z)-2-aryl-6,7-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidin-3(2H)-one,1’-methyl-4’-aryl-6",7"-dihydro-5"H-dispiro[indole-3,2’-pyrrolidine-3’,2"-[1,3]thiazolo[3,2-a]pyrimidine]-2,3"(1H)-dione)3. Two classe s of isoxazole compounds were synthesized via the1,3-dipolar cycloaddition from(ethyl(2Z)-2-(2-methoxy-2-oxo-ethylidene)-7-methyl-3-oxo-5-aryl-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-c arboxylate and methyl(2Z)-(3-oxo-5-aryl-5a,7,8,9a-tetra-hydro-5H,6H-pyrano[2,3-d][1,3]thiazolo[3,2-a]pyrimidin-2(3H)-ylidene)acetate)to2,6-dichlorobenzonitrile oxide.All the novel heterocycle compounds were charactered thoroughly by MS, IR, elementary analysis, NMR together with X-ray crystallographic analysis.