We have demonstrated a facile synthesis of diversely substituted quinazolines and 3,4-dihydroquinazolines through the o-iodoxybenzoic acid (IBX) mediated tandem reaction of readily available o-aminobenzylamine and aldehydes. The yield of the reactions generally ranged from 70\% to 95\%. This mild protocol provides an efficient strategy toward the synthesis of these classes of heterocycles. © Georg Thieme Verlag Stuttgart.

Subhabrata Sen

Chemistry

(SoNS) School of Natural Sciences

Hati S.

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Shiv Nadar University

Synthesis (Germany)

Catalytic cerium chloride was found to activate 2-iodoxybenzoic acid (IBX) for the oxidative dehydrogenation of tetrahydroisoquinolines, tetrahydro-β-carbolines, and thiazolidines to their dehydrogenated and aromatic forms at room temperature in moderate to excellent yields. The robustness of the protocol was demonstrated by scaling up the reactions to multigram quantities. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

European Journal of Organic Chemistry

Cerium Chloride Catalyzed, 2-Iodoxybenzoic Acid Mediated Oxidative Dehydrogenation of Multiple Heterocycles at Room Temperature

Nitrogen heteroarenes form an important class of compounds which can be found in natural products, synthetic drugs, building blocks etc. Among the diverse strategies that were developed for the synthesis of nitrogen heterocycles, oxidative dehydrogenation is extremely effective. This review discusses various oxidative dehydrogenation strategies of C-C and C-N bonds to generate nitrogen heteroarenes from their corresponding heterocyclic substrates. The strategies are categorized under stoichiometric and catalytic usage of reagents that facilitate such transformations. The application of these strategies in the synthesis of nitrogen heteroarene natural products and synthetic drug intermediates are also discussed. We hope this review will arouse sufficient interest among the scientific community to further advance the application of oxidative dehydrogenation in the synthesis of nitrogen heteroarenes. © 2017 Hati et al.; Licensee Beilstein-Institut.

Fulltext

Beilstein Journal of Organic Chemistry

Oxidative dehydrogenation of C-C and C-N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

An exceptional oxone mediated tandem transformation of 2-aminobenzylamines to 2-substituted benzimidazoles is reported. It occurs at room temperature with aromatic, heteroaromatic, and aliphatic aldehydes. In this reaction initial condensation of 2-aminobenzylamine with appropriate aldehydes afforded a tetrahydroquinazoline intermediate which underwent oxone-mediated ring distortion to afford the desired compounds in moderate to excellent yields. © 2016 American Chemical Society.

Organic Letters

Accessing Benzimidazoles via a Ring Distortion Strategy: An Oxone Mediated Tandem Reaction of 2-Aminobenzylamines

Herein, we report a facile synthesis of 3,4-dihydro-β-carbolines and aromatic β-carbolines from tetrahydro-β-carbolines, mediated by N-bromosuccinimide in toluene at 0°C to room temperature (rt), in good to moderate yields. © 2016 Elsevier Ltd. All rights reserved.

Tetrahedron Letters

N-Bromo-succinimide promoted synthesis of β-carbolines and 3,4-dihydro-β-carbolines from tetrahydro-β-carbolines

Chemical Communications

The cascade synthesis of quinazolinones and quinazolines using an α-MnO2 catalyst and tert-butyl hydroperoxide (TBHP) as an oxidant

RSC Adv.

Copper-catalyzed intermolecular cyclization of nitriles and 2-aminobenzylamine for 3,4-dihydroquinazolines and quinazolines synthesis via cascade coupling and aerobic oxidation

Tetrahedron

Copper-catalyzed domino reaction between 1-(2-halophenyl)methanamines and amidines or imidates for the synthesis of 2-substituted quinazolines

Chemistry - An Asian Journal

Synthesis of Quinazolines and Tetrahydroquinazolines: Copper-Catalyzed Tandem Reactions of 2-Bromobenzyl Bromides with Aldehydes and Aqueous Ammonia or Amines

Synthesis of Quinazolines and Dihydroquinazolines: o-Iodoxybenzoic Acid Mediated Tandem Reaction of o-Aminobenzylamine with Aldehydes