An efficient and highly versatile method for the synthesis of diverse regiospecific 1-arylbenzotriazoles being important medicinal scaffolds, by the copper (1) catalysed intramolecular N-arylation of diazoaminobenzenes of 2-haloaryldiazonium salts in PEG-water has been developed. A very simple reaction protocol, large number of substrate affordability and excellent yields are the main features of this methodology. © 2010 The Royal Society of Chemistry.

CHHANDA MUKHOPADHYAY

Chemistry

P K TAPASWI

R J BUTCHER

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Organic and Biomolecular Chemistry

A highly efficient and simple protocol for the N-arylation of some hindered aza-heterocycles in water has been developed with readily available basic copper carbonate as the catalyst using bis(3,5-dimethyl-1H-pyrazol-1-yl)methane as ligand. This mild catalytic system possesses excellent tolerance for a large variety of functional groups. A total of 11 previously unknown coupling products have been synthesized by this methodology. © 2012 Taylor &amp; Francis Group, LLC.

Synthetic Communications

Highly efficient and simple catalytic system for the N-arylation of some hindered aza-heterocycles in water

Potassium hydrogen sulfate in the presence of dibenzo-18-crown-6 (DB18C6) turns out to be a very efficient and effective catalyst for the facile synthesis of a wide variety of tri- and tetrasubstituted imidazoles in an aqueous medium at moderate temperature. The idea behind this is that the potassium ion, being trapped in the crown core, frees the hydrogen sulfate anion, which, because of its acidic nature, succeeds in the ready synthesis of the imidazoles. © 2012 Copyright Taylor and Francis Group, LLC.

Fulltext

Green Chemistry Letters and Reviews

A facile and efficient synthesis of tri- and tetrasubstituted imidazoles with potassium hydrogen sulfate and DB18C6 in an aqueous medium

Pd(0) catalyzed carbonylative annulation reaction of 1-(2-iodophenyl)-3-aryltriaz-1-enes in the presence of DABCO and 1 atm of carbon monoxide in toluene at 80 °C gave the corresponding 3-arylbenzo-1,2,3-triazin-4(3H)-ones with high selectivity and in excellent yields. Substrate scope of this reaction is demonstrated with 24 examples with various halo, alkyl, and alkoxy substituents on either of the aromatic rings. Bromo substituted triazenes were less reactive as starting materials toward the carbonylative annulation reaction and yielded 3-arylbenzo-1,2,3-triazin-4(3H)-ones in good to moderate yields in the presence of only xantphos as an additive. In the absence of CO (under N2 atmosphere), the reaction did not proceed, and only starting material was recovered. However, in the presence of catalytic amount of CO or in the presence of Ph3P in catalytic amounts as additives, the reactions proceeded to yield the corresponding 1-aryl-(1H)-benzo-1,2,3-triazoles selectively in good yields. On the basis of control experiments, a plausible reaction mechanism for the selective formation of 3-arylbenzo-1,2,3-triazin-4(3H)-ones in the presence of CO and1-aryl-(1H)-benzo-1,2,3-triazoles in the absence of CO through a common intermediate was proposed. © 2017 American Chemical Society.

Journal of Organic Chemistry

Selective Synthesis of 3-Arylbenzo-1,2,3-triazin-4(3H)-ones and 1-Aryl-(1H)-benzo-1,2,3-triazoles from 1,3-Diaryltriazenes through Pd(0) Catalyzed Annulation Reactions

Only 15 mol% of l-proline in ethanol proved to be a very efficient catalyst for the one-pot synthesis of a wide variety of highly substituted pyridines at room temperature. The methodology is mild, efficient, high yielding, and the products can be directly recrystallized from hot ethanol. © 2010 Elsevier Ltd. All rights reserved.

Tetrahedron Letters

l-Proline-catalyzed one-pot expeditious synthesis of highly substituted pyridines at room temperature

The Journal of Organic Chemistry

Copper(I)-Catalyzed Synthesis of Substituted 2-Mercapto Benzimidazoles

Organic Letters

Assembly of Isoquinolines via CuI-Catalyzed Coupling of β-Keto Esters and 2-Halobenzylamines

A One-Pot Coupling/Hydrolysis/Condensation Process to Pyrrolo[1,2-a]quinoxaline

Synthesis of Indolines via a Domino Cu-Catalyzed Amidation/Cyclization Reaction

A ligand-free copper (1) catalysed intramolecular N-arylation of diazoaminobenzenes in PEG-water: An expeditious protocol towards regiospecific 1-aryl benzotriazoles

Journal	Organic and Biomolecular Chemistry
Publisher	ROYAL SOC CHEMISTRY
ISSN	1477-0520
Open Access	No