AlCl3-Mediated CHF2 Transfer and Cyclocondensation of Difluoromethoxy Functionalized o-Phenylenediamines to Access N-Substituted Benzimidazoles

Vinayagam, Vinothkumar; Karre, Satish Kumar; Kasu, Sreenivasa Reddy; Srinath, Ravuri; Bathula, Hema Sundar Naveen Babu; Sadhukhan, Subir Kumar

doi:10.1021/acs.orglett.2c02231

Cited by 4 publications

(3 citation statements)

References 54 publications

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“…Interestingly, a transition metal‐free, frustrated Lewis pair‐catalyzed (AlCl 3 in CH 2 Cl 2 ) novel synthetic approach was devised by Vinayagam et al [166] . in 2022 to access pharmaceutically vital N ‐substituted benzimidazoles 185 following a sustainable, environment‐friendly organic transformation (Scheme 141).…”

Section: Synthesis Of Benzimidazole Benzoxazole and Benzothiazole Der...mentioning

confidence: 99%

“…Interestingly, a transition metal-free, frustrated Lewis paircatalyzed (AlCl 3 in CH 2 Cl 2 ) novel synthetic approach was devised by Vinayagam et al [166] in 2022 to access pharmaceutically vital N-substituted benzimidazoles 185 following a sustainable, environment-friendly organic transformation (Scheme 141). This frustrated Lewis pair-catalyzed synthetic method was observed to accommodate intramolecular migration of the CHF 2 group from an oxygen atom to the neighboring nitrogen atom, followed by cyclocondensation at room temperature.…”

Section: The Protocols To Access Benzimidazoles and Their Derivatives...mentioning

confidence: 99%

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Recent Advancements in Strategies for the Synthesis of Imidazoles, Thiazoles, Oxazoles, and Benzimidazoles

Kant,

Patel,

Banerjee

et al. 2023

ChemistrySelect

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Nitrogen‐containing heterocycles such as imidazoles, thiazoles, and oxazoles play a significant role in the fields of biological and pharmaceutical chemistry. These compounds were widely used for agrochemical, pesticide, medicinal, and industrial applications. Due to the wide spectrum of structural diversity as well as the biological and pharmaceutical activity of N‐heterocycles, a plethora of reports on their synthesis have appeared in the last few decades. However, developments in various bond‐forming strategies such as C−C, C−N, C−O, C−S, and N−N, as well as C−H activation, have been used as a powerful synthetic tool to derive copious N‐heterocycles. The most prominent and fascinating reports on the synthesis of imidazole, thiazole, oxazoles, and benzimidazole moieties by C−C and C−N coupling reactions, multi‐component and cycloaddition reactions, C−H activation, etc. are discussed in this study. These studies demonstrated the enormous potential of such methods for accelerating modern chemical synthesis and establishing molecular beauty through bonding. The various aspects of the methodologies, like optimized conditions, substrate scope, and mechanistic investigations, are discussed in detail.

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Section: Synthesis Of Benzimidazole Benzoxazole and Benzothiazole Der...mentioning

confidence: 99%

Section: The Protocols To Access Benzimidazoles and Their Derivatives...mentioning

confidence: 99%

Recent Advancements in Strategies for the Synthesis of Imidazoles, Thiazoles, Oxazoles, and Benzimidazoles

Kant,

Patel,

Banerjee

et al. 2023

ChemistrySelect

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“…Another valuable utility of HFIP is the critical role it has exhibited in the synthesis of designer acids, implying that the acidity of Brønsted acids and Lewis acids can be modified by combining these with HFIP. Based on our research interests in Lewis acid catalysis and literature reports, we envisaged that the combination of appropriate Lewis acids or Brønsted acids with HFIP could deprotect the N -Cbz group. − …”

Section: Introductionmentioning

confidence: 99%

Mild Method for Deprotection of the N-Benzyloxycarbonyl (N-Cbz) Group by the Combination of AlCl₃ and HFIP

Vinayagam,

Sadhukhan,

Botla

et al. 2024

J. Org. Chem.

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Herein, we report our findings on the novel ability of aluminum chloride (AlCl 3 ) in fluorinated solvent 1,1,1,3,3,3hexafluoroisopropanol [HFIP] to selectively deprotect the N-benzyloxycarbonyl group (N-Cbz). The salient features of this method are good functional group tolerance including other reducible groups, cost-effectiveness, easy-to-handle, safe protocol, amenable to scale-up, high yields, and ambient temperature reactions. The methodology would serve as an excellent alternative to the use of pyrophoric hydrogen gas and metal catalyst reagents that pose severe safety and environmental concerns. The most notable feature of this methodology is the orthogonal deprotection of the N-Cbz group in the presence of O-and N-Bn protecting groups, hence, expanding the scope for designing synthetic routes to target compounds requiring multiple functional group transformations.

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One‐Pot Synthesis of C‐Substituted bis‐Benzimidazoles and Benzobisimidazoles via Reductive Cyclization of o‐Nitroaniline Derivatives and Aldehydes using Sodium Metabisulfite in a Microwave Reactor

Cherukumalli,

Prasad,

Khanna

et al. 2024

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Herein, we report a simple and an economical method to synthesize C‐substituted bis‐benzimidazole and C‐substituted benzobisimidazole derivatives in moderate to excellent yields using sodium metabisulfite, under microwave irradiation conditions. The most attractive feature of the methodology is the three‐step yet one‐pot condensation of nitroarenes with various benzaldehyde derivatives to synthesize useful benzimidazoles, and an easy product isolation method by simple solvent trituration techniques. The methodology can be fine‐tuned to synthesize selectively the mono C‐substituted benzimidazoles, leaving a nitroaniline functionality intact for preparing a variety of unsymmetrical C‐substituted bis‐benzimidazoles.

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AlCl₃-Mediated CHF₂ Transfer and Cyclocondensation of Difluoromethoxy Functionalized o-Phenylenediamines to Access N-Substituted Benzimidazoles

Cited by 4 publications

References 54 publications

Recent Advancements in Strategies for the Synthesis of Imidazoles, Thiazoles, Oxazoles, and Benzimidazoles

Recent Advancements in Strategies for the Synthesis of Imidazoles, Thiazoles, Oxazoles, and Benzimidazoles

Mild Method for Deprotection of the N-Benzyloxycarbonyl (N-Cbz) Group by the Combination of AlCl₃ and HFIP

One‐Pot Synthesis of C‐Substituted bis‐Benzimidazoles and Benzobisimidazoles via Reductive Cyclization of o‐Nitroaniline Derivatives and Aldehydes using Sodium Metabisulfite in a Microwave Reactor

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AlCl3-Mediated CHF2 Transfer and Cyclocondensation of Difluoromethoxy Functionalized o-Phenylenediamines to Access N-Substituted Benzimidazoles

Cited by 4 publications

References 54 publications

Recent Advancements in Strategies for the Synthesis of Imidazoles, Thiazoles, Oxazoles, and Benzimidazoles

Recent Advancements in Strategies for the Synthesis of Imidazoles, Thiazoles, Oxazoles, and Benzimidazoles

Mild Method for Deprotection of the N-Benzyloxycarbonyl (N-Cbz) Group by the Combination of AlCl3 and HFIP

One‐Pot Synthesis of C‐Substituted bis‐Benzimidazoles and Benzobisimidazoles via Reductive Cyclization of o‐Nitroaniline Derivatives and Aldehydes using Sodium Metabisulfite in a Microwave Reactor

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AlCl₃-Mediated CHF₂ Transfer and Cyclocondensation of Difluoromethoxy Functionalized o-Phenylenediamines to Access N-Substituted Benzimidazoles

Mild Method for Deprotection of the N-Benzyloxycarbonyl (N-Cbz) Group by the Combination of AlCl₃ and HFIP