Competitive reactivity of the aryl isothiocyanate dipolarophile at N=C versus C=S with nucleophilic 1,3-dipoles:: a combined experimental and theoretical study.: The reactions of substituted 1,2,3-triazolium-1-aminide 1,3-dipoles with aryl isothiocyanates:: new tricyclic thiazolo[4,5-d][1,2,3]triazoles

Substituted 1,2,3-triazolium-1-aminide 1,3-dipoles react with aryl isothiocyanates at both the N=C and C=S sites to give mixtures of substituted imidazolo[4,5-d][1,2,3]triazoles and new thiazolo[4,5-d][1,2,3]-triazoles including tricyclic derivatives with the C-3a and C-6a bridgeheads linked via (CH2)(4) and phenanthro groups, The product distribution is controlled by the para-substituent of the aryl isothiocyanate, Theoretical calculations, 3-21G* and 6-31G*, suggest that linear triple bonded canonical forms of the aryl isothiocyanate system play a key role in the ambident reactivity of these systems.