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Title: New applications of 5-amino-1,2,3-triazoles in the synthesis of functionalised heterocycles
Author: Dwyer, P. Owen
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1992
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The ability of 5-amino-1-arylmethyl-1H-1,2,3-triazole derivatives to undergo novel diazotative deaminative cyclisation reactions to afford 1,2,3-triazolo[5,1-a] isoindolenines was also studied. The mechanism of this novel type of deaminative cyclisation reaction was investigated and the results obtained suggest the involvement of previously undescribed 1,2,3-triazolyl cation species. Attempts to induce the acid-catalysed triazole scission of 1,2,3-triazolo[5,1-a]isoindolenine derivatives led to the formation of intractable materials presumably derived from the polymerisation of the isoindolenine cleavage products. It was found that the diazotisation of 5-amino-1-arylmethyl-1H-1,2,3-triazole derivatives with arylmethyl groups activated by powerful electron-donating substituents, such as a methoxyl, resulted in cyclisation to afford derivatives of the novel 1,2,3-triazolo[5,1-c]benzo-,2,4-triazepine ring system. It was also found that such 1,2,3-triazolo[5,1-c]benzo-1,2,4-triazepine derivatives showed a tendency to undergo base-catalysed tautomerism leading to loss of the aromaticity due to the benzene ring. In addition, the acid-catalysed triazole scission of triazolobenzo-1,2,4-triazepine derivatives was studied and shown to be disfavoured. The scope of the diazotative deaminative cyclisation reactions of various 5-amino-1-aryl-1H-1,2,3-triazole derivatives was investigated and shown to provide practical methods for the synthesis of bridgehead-fused 1,2,3-triazolobenzoisoquinoline and 1,2,3-triazolophenanthridine derivatives. The acid-catalysed triazole scission of 1,2,3-triazolophenanthridine derivatives was demonstrated to provide a viable route to usefully functionalised phenanthridine derivatives. In contrast 1,2,3-triazolobenzoisoquinoline derivatives proved to be stable to acid-catalysed triazole scission.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available