1.2.4- Triazolo-bridgehead heterocycles synthesis

Of the condensed heterocycles containing a bridgehead nitrogen atom that have been subjected to the Anil Synthesis, the 2-arylimidazo[l,2-a]-pyridine system exhibits good alkali stability, whereas the 2-aryl-j-triazolo[l,5-a]pyridine system may only be reacted below 45°C.19,78... 

The other three chapters in the present volume all deal with bicyclic heterocycles. Dr. H. K. Pujari of Kurukshetra University in India describes condensed 4-thiazolidinones, and Professor M. A. E. Shaban and A. Z. Nasr of Alexandria University in Egypt survey the synthesis of condensed 1,2,4-triazolo heterocycles. Finally, Professor T. A. Crabb of Portsmouth, England has covered saturated bicyclic 6/5 ring-fused systems with a bridgehead nitrogen and a single additional heteroatom. None of these groups of bicyclic heterocycles has been comprehensively reviewed before. 

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