Failure Synthesis of 1,5-disubstituted endo-heterobicyclic 1,2,3-Triazolo-1,4-Oxazines

Abstract

Negative results were obtained on the synthesis of the endo-polyheterocyclic bridged 1,2,3-triazolo-1,4-oxazine isomers. As in case of the non-catalyzed reaction, only the exo-heteropolycyclic fused isomers were obtained. No effect on the reaction orientation was observed when Cu(I) was used as catalyst or in equal molar ratio. The bridged isomer was neither obtained via another synthetic route. We reversed the reactions order to obtain the corresponding bromohydroxy triazole but the cycloetherification step leads to the formation of the polymeric product.