2-Azidobenzaldehyde derivatives

A four-component reaction involving tandem indium chloride-catalyzed cyclocondensation of ammonium acetate 124, glyoxal derivatives 125,2-azidobenzaldehyde derivatives 126, and propargylamines 127 followed by intramolecular azide-alkyne 1,3-dipolar cycloaddition reactions afforded highly functionalized benzo-imidazo-triazolodiazepines 128 (130L4492). 

Benzaldehyde and derivs 2 B35 azidobenzaldehyde 2 B35 azobenzaldehyde 1 A646 azoxybenzaldehyde and derivs 1 A666 3-benzaldehyde-3-diazoniumcliloride 2 B3S dinitrobenzaldehyde 2 B35... 

Triazanaphthalene has not been prepared but several observations suggest that it would behave as an unstable diazonium compound. The neutral species of the 3-oxide was stable at pH 7.1, although it decomposed readily in acid solution. The neutral species was considered to be anhydrous because the spectrum at pH 7.1 resembled that of 4-methyl-l,2,3-triazanaphthalene 3-oxide, in which hydration would be minimized by the blocking effect of the methyl group.Decomposition in acid most probably involves addition of water across C-4 and N-3 because o-azidobenzaldehyde was formed. The 4-methyl derivative underwent similar decomposition. 

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