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

Subhabrata Sen

Chemistry

(SoNS) School of Natural Sciences

Hati S.

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Shiv Nadar University

European Journal of Organic Chemistry

Background: Despite numerous efforts to eradicate the disease, malaria continues to remain one of the most dangerous infectious diseases plaguing the world. In the absence of any effective vaccines and with emerging drug resistance in the parasite against the majority of anti-malarial drugs, the search for new drugs is urgently needed for effective malaria treatment. Methods: The goal of the present study was to examine the compound library, based on indoles generated through diversity-oriented synthesis belonging to four different architecture, i.e., 1-aryltetrahydro/dihydro-β-carbolines and piperidine/pyrrolidine-fused indole derivatives, for their in vitro anti-plasmodial activity. Trifluoroacetic acid catalyzed transformation involving tryptamine and various aldehydes/ketones provided the library. Results: Among all the compounds screened, 1-aryltetrahydro-β-carbolines 2 and 3 displayed significant anti-plasmodial activity against both the artemisinin-sensitive and artemisinin-resistant strain of Plasmodium falciparum. It was observed that these compounds inhibited the overall parasite growth in intra-erythrocytic developmental cycle (IDC) via reactive oxygen species-mediated parasitic death and thus could be potential anti-malarial compounds. Conclusion: Overall the compounds 2 and 3 identified in this study shows promising anti-plasmodial activity that can kill both artemisinin-sensitive and artemisinin-resistant strains of P. falciparum. © 2021, The Author(s).

Fulltext

Malaria Journal

Diversity-oriented synthesis derived indole based spiro and fused small molecules kills artemisinin-resistant Plasmodium falciparum

Antimicrobial drug resistance is one of the most critical problems that plagued the human race in modern times. Discovery of novel antibiotics is important to counter this threat. Accordingly, herein we have reported the discovery of substituted benzimidazole class of molecules with antimicrobial property (specifically against Staphylococcus aureus). They were initially identified through a random screening and a novel catalytic synthetic strategy was utilized to access them. in vitro screening and phenotypic profiling revealed the antimicrobial nature. De novo transcriptome and gene analyses predicted the putative targets. This work provides a solid foundation for developing the benzimidazoles as a target specific antimicrobial preclinical candidate. © 2019 Wiley Periodicals, Inc.

Drug Development Research

Transcriptome analysis predicts mode of action of benzimidazole molecules against Staphylococcus aureus UAMS-1

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.

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

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.

Synthesis (Germany)

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

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

Bioinspired Organocatalytic Aerobic C–H Oxidation of Amines with anortho-Quinone Catalyst

Organic & Biomolecular Chemistry

PhI(OAc)2-mediated one-pot oxidative decarboxylation and aromatization of tetrahydro-β-carbolines: synthesis of norharmane, harmane, eudistomin U and eudistomin I