50871-87-9

Upstream product

• 624-84-0 formic acid hydrazide 
• 622-16-2 1,3-Diphenylcarbodiimide 
• 102-08-9 N,N-diphenylthiourea 
• 103-72-0 phenyl isothiocyanate 
• 62-53-3 aniline 
• 64-18-6 formic acid 
• 56004-08-1 N-amino-N',N''-diphenyl-guanidine 

Relevant academic research and scientific papers

Palladium catalyzed carbonylative annulation of the C(sp2)-H bond of N,1-diaryl-1H-tetrazol-5-amines and N,4-diaryl-4H-triazol-3-amines to quinazolinones

Pd(ii) catalyzed direct C-H carbonylative annulation of N,1-diaryl-1H-tetrazol-5-amines and N,4-diaryl-4H-1,2,4-triazol-3-amines gave the corresponding triazole and tetrazole fused quinazolinones in good yields. This methodology offers a convenient method for the synthesis of these important heterocyclic scaffolds in a highly atom economical process. On the mechanistic aspect weakly nucleophilic triazole and tetrazole moieties function as both directing as well as intramolecular nucleophiles. The catalytically active C-H activated intermediate dimeric Pd complex was isolated and characterized which on exposure to CO gas gave the corresponding tetrazole fused quinazolinone derivative. On the basis of isolation of the intermediate and observed kinetic isotope effects, a mechanism has been proposed for the C-H activated direct carbonylative annulation reaction.

An expedient route to the azoles through oxidative desulfurization using iodine reagent

A novel and expedient regioselective method for the synthesis of 5-aminotetrazoles and 3-amino-1,2,4-triazoles through oxidative desulfurization of corresponding 1,3-disubstituted thioureas has been discovered and optimized for the process conditions. The process is broadly applicable to structurally diverse 1,3-disubstituted thioureas.

Tandem synthesis of [1,2,4]-triazoles mediated by iodine - A regioselective approach

A tandem regioselective one-pot synthesis of 3-amino-[1,2,4]-triazoles has been achieved from 1,3-disubstituted thioureas using molecular iodine. In this one-pot strategy, the intermediate carbodiimide generated in situ from thiourea upon reaction with HCONHNH2 gives diaryl/ alkylhydrazinecarboximidamide or acylureidrazone, which then undergoes an intramolecular cyclodehydration to afford the corresponding 3-amino-[1,2,4]- triazole. The product regioselectivity for unsymmetrical 1,3-disubstituted thioureas correlate well with the pKas of the parent amines attached, in which the amine having higher pKa goes to the ring nitrogen while the other nitrogen remains flanked as an exocyclic nitrogen of the triazole core. This method is milder and environmentally sustainable giving good to excellent yields of the desired products.

O -iodoxybenzoic acid mediated oxidative desulfurization initiated domino reactions for synthesis of azoles

A systematic exploration of thiophilic ability of o-iodoxybenzoic acid (IBX) for oxidative desulfurization to trigger domino reactions leading to new methodologies for synthesis of different azoles is described. A variety of highly substituted oxadiazoles, thiadiazoles, triazoles, and tetrazoles have been successfully synthesized in good to excellent yields, starting from readily accessible thiosemicarbazides, bis-diarylthiourea, 1,3-disubtituted thiourea, and thioamides.

Desulfurization strategy in the construction of azoles possessing additional nitrogen, oxygen or sulfur using a copper(I) catalyst

A tandem and convergent approach to various N-, O-, or S-containing azoles has been developed by exploiting the thiophilic property of copper( I) iodide used in a catalytic quantity. The present protocol gives access to amino-substituted tetrazoles, triazoles, oxadiazoles and thiadiazoles via oxidative desulfurization of their respective precursors followed by inter- or intramolecular attack of suitable nucleophiles. For aminotetrazoles and triazoles an excellent regioselectivity has been achieved through proper tuning of the pKa values of the parent amines attached to unsymmetrical thioureas. The method represents an autocatalytic process in which copper( I) iodide gets converted to copper(II) sulfide which in turn transforms to active copper(II) oxide that effectively carries forward the catalytic cycle. The fate of the copper catalyst has also been studied using scanning electron microscopic (SEM) and energy-dispersive X-ray spectroscopic (EDS) analyses which give an insight into the mechanism for this catalytic process.

A facile one-pot synthetic method for 1,2,4-triazoles and 1,3-disubstituted thioureas

The reaction of arylisothiocyanates with triethylamine and acylhydrazides in the presence of mercuric acetate has been studied. The reaction proceeds through the formation of thiourea, followed by a sequential addition-dehydration with acylhydrazides. The initial detection of thiourea, which mediates the formation of disubstituted 1,2,4-triazoles, is explained by a plausible mechanism.

Synthetic studies toward aryl-(4-aryl-4H-[1,2,4]triazole-3-yl)-amine from 1,3-diarylthiourea as urea mimetics

A thiophile-promoted synthesis of disubstituted 4H-[1,2,4]triazole-3-yl- amines as urea mimetics from the corresponding 1,3-disubstituted thioureas has been studied, and the scope and limitations of this reaction are presented. The reaction proceeds through the formation of a carbodiimide, followed by a sequential addition-dehydration with acyl hydrazides. 1,3-Branched dialkylthioureas result in the formation of the corresponding ureas. The electronic and steric effects of the substitution on the phenyl rings of the 1,3-diarylthioureas play an important role in the formation of the intermediary carbodiimde and the direction of the subsequent ring closure of the N-acyl hydrazide adduct.