ISSN:
1434-193X
Keywords:
Azides
;
Betaines
;
Carbenes
;
Nitrogen heterocycles
;
Nucleophilic aromatic substitution
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Nitrogen-rich mesoions have been synthesized by the reaction of the 5-chloro-1,3-diaryltetrazolium salt 1 with various nitrogen nucleophiles. The reactions with aqueous ammonia and hydroxylamine gave tripolar mesoionic amide 2 and mesoionic hydroxylamide 4, respectively. N-Substituted and N,N-disubstituted hydrazines yielded the corresponding hydrazides 5, whereas N,N-diphenylhydrazine gave the rearranged product 6. The reaction with sodium azide gave 5-azidotetrazolium salt 8. The azido group of 8 was reduced to give aminotetrazolium salt 9, deprotonation of which yielded the corresponding conjugate base 3. Hard nucleophiles attacked the tetrazolium carbon atom of 8 to give substitution products, whereas soft nucleophiles added the terminal nitrogen atom of the azido group to give addition products. Azidotetrazolium salt 8 reacted further with sodium azide to give a high yield of the tetrazol derivative 11, together with a small amount of triazene 17. The intermediacy of mesoionic carbene 19 is postulated.
Type of Medium:
Electronic Resource
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