Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

Abstract

The conversion of tetrazolo[1,5-a]quinoxalines to 1,2,3-triazoloquinoxalines and triazoloimidazoquinoxalines under typical conditions of a CuAAC reaction has been investigated. Derivatives of the novel compound class of triazoloimidazoquinoxalines (TIQ) and rhenium(I) triazoloquinoxaline complexes as well as a new TIQ rhenium complex were synthesized. As a result, a small 1,2,3-triazoloquinoxaline library was obtained and the method could be expanded towards 4-substituted tetrazoloquinoxalines. The compatibility of various aliphatic and aromatic alkynes towards the reaction was investigated and the denitrogenative annulation towards imidazoloquinoxalines could be observed as a competing reaction depending on the alkyne concentration and the substitutions at the quinoxaline.

SnAr Reactions of 2,4-Diazidopyrido[3,2-d]pyrimidine and Azide-Tetrazole Equilibrium Studies of the Obtained 5-Substituted Tetrazolo[1,5-a]pyrido[2,3-e]pyrimidines

“…A complex mixture of unidentified products was obtained in the reaction of diazide 2 with phenol, most probably due to further substitution reactions of the phenyloxy moiety as a leaving group. Given that the compounds 2-5 persist in equilibrium between tetrazolo[1,5-a]pyrimidines and 2-azidopyrimidines, it should be possible to functionalize them as hetarylazides [12,34] and tetrazoles [35]. Indeed, a series of 1,2,3-triazole-substituted pyrido [3,2-d] Substitution of diazide 2 with simple alcohols proceeded in the presence of a base (K 2 CO 3 ) in dry MeCN, yielding products 5a and 5b (Scheme 4), although the products were obtained in low yields, mainly due to partial hydrolysis in the basic reaction medium as a side reaction.…”

“…A complex mixture of unidentified products was obtained in the reaction of diazide 2 with phenol, most probably due to further substitution reactions of the phenyloxy moiety as a leaving group. Given that the compounds 2-5 persist in equilibrium between tetrazolo[1,5-a]pyrimidines and 2-azidopyrimidines, it should be possible to functionalize them as hetarylazides [12,34] and tetrazoles [35]. Indeed, a series of 1,2,3-triazole-substituted pyrido [3,2-d] Given that the compounds 2-5 persist in equilibrium between tetrazolo[1,5-a]pyrimidines and 2-azidopyrimidines, it should be possible to functionalize them as hetarylazides [12,34] and tetrazoles [35].…”

“…Given that the compounds 2-5 persist in equilibrium between tetrazolo[1,5-a]pyrimidines and 2-azidopyrimidines, it should be possible to functionalize them as hetarylazides [12,34] and tetrazoles [35]. Indeed, a series of 1,2,3-triazole-substituted pyrido [3,2-d] Given that the compounds 2-5 persist in equilibrium between tetrazolo[1,5-a]pyrimidines and 2-azidopyrimidines, it should be possible to functionalize them as hetarylazides [12,34] and tetrazoles [35]. Indeed, a series of 1,2,3-triazole-substituted pyrido [3,2-d] Synthesis of 2,4-bistriazole from diazide 2 was not successful due to the formation of multiple side products.…”

Convenient synthesis of 2-chloro-3-substituted quinoxalines by visible-light-induced radical cascade cyclization of ortho-diisocyanoarenes with sulfinic acids

“…The low yield, requirement of high temperature and high cost, however, severely hurt both of these strategies. 8–10 Therefore, it is extremely desired and demanding to explore novel, efficient, low-cost and practical methodologies for making 2-chloro-3-substituted quinoxalines ( 3 ).…”

Synthesis of Substituted Triazole-Pyrazole Hybrids using Triazenopyrazoles Precursors

“…[1,2] We were interested in feasible strategies to synthesize nitrogen-rich heterocyclic scaffolds that can extend the currently available libraries with new drug-like molecules. Our past work on pyrazoles [3][4][5][6] and triazoles [7][8][9][10][11] motivated us to search for suitable and versatile strategies to explore access to triazole-pyrazole hybrids. Triazole-pyrazole hybrids, particularly non-fused heterocycles of this class, have not been investigated systematically.…”