Recent Developments Towards Synthesis of (Het)arylbenzimidazoles

Synthesis ◽  
2021 ◽  
Author(s):  
Vakhid A. Mamedov ◽  
Nataliya A. Zhukova
Keyword(s):  
Oxidative Cyclization ◽  
Environmentally Benign ◽  
Benzimidazole Derivatives ◽  
Primary Alcohols ◽  
Molecular Scaffolds ◽  
Carbon Fragment ◽  
The Us ◽  
Methods Of Synthesis ◽  
Recent Developments ◽  
Ring Distortion

AbstractBenzimidazole is an important heterocycle that is widely researched and utilized by the pharmaceutical industry and is one of the five most commonly used five-membered aromatic heterocyclic compounds approved by the US Food and Drug Administration. In view of their wide-ranging bioactivities, systems containing benzimidazole as one of the moieties occupy a special place among other benzimidazole derivatives. Since 2010, many improved synthetic strategies have been developed for the construction of hetaryl- and arylbenzimidazole molecular scaffolds under environmentally benign conditions. This review emphasizes the recent trends and modifications frequently used in the synthesis of derivatives of benzimidazole such as the Phillips–Ladenburg and Weidenhagen reactions, as well as entirely new methods of synthesis, involving oxidative cyclization, cross-coupling, ring distortion strategy, and rearrangements carried out under environmentally benign conditions.1 Introduction2 From 1,2-Diaminobenzenes with Various One-Carbon Unit Suppliers2.1 Phillips–Ladenburg Reaction2.1.1 With (Het)arenecarboxylic Acids2.2.2 With (Het)arenecarboxylic Acid Derivatives2.2 Weidenhagen Reaction2.2.1 With (Het)arenecarbaldehydes or (Het)aryl Methyl Ketones2.2.2 With Primary Alcohols2.2.3 With Primary Alkylamines2.2.4 With 2-Methylazaarenes2.2.5 With Other One-Carbon Fragment Suppliers3 From 2-Haloacetanilides and Amines4 From Amidines5 From Tetrahydroquinazolines6 Mamedov Rearrangement7 Conclusions and Outlook

scholarly journals Recent advances in the electrochemical construction of heterocycles

2014 ◽  
Vol 10 ◽  
pp. 2858-2873 ◽  
Author(s):  
Robert Francke
Keyword(s):  
Heterocyclic Compounds ◽  
Elevated Temperatures ◽  
Ring Formation ◽  
Environmentally Benign ◽  
Heterocyclic Chemistry ◽  
Ambient Conditions ◽  
Recent Developments ◽  
Strong Acids ◽  
Selection Of ◽  
Made In

Due to the fact that the major portion of pharmaceuticals and agrochemicals contains heterocyclic units and since the overall number of commercially used heterocyclic compounds is steadily growing, heterocyclic chemistry remains in the focus of the synthetic community. Enormous efforts have been made in the last decades in order to render the production of such compounds more selective and efficient. However, most of the conventional methods for the construction of heterocyclic cores still involve the use of strong acids or bases, the operation at elevated temperatures and/or the use of expensive catalysts and reagents. In this regard, electrosynthesis can provide a milder and more environmentally benign alternative. In fact, numerous examples for the electrochemical construction of heterocycles have been reported in recent years. These cases demonstrate that ring formation can be achieved efficiently under ambient conditions without the use of additional reagents. In order to account for the recent developments in this field, a selection of representative reactions is presented and discussed in this review.

Electrochemical Oxidative Cyclization of Alkenes, Boronic Acids, and Dichalcogenides to Access Chalcogenated Boronic Esters and 1,3-Diols

2021 ◽  
Author(s):  
Changfeng Huang ◽  
Jijing Hu ◽  
Guangxian Chen ◽  
Minjian Wu ◽  
Hua Cao ◽  
...  
Keyword(s):  
Boronic Acids ◽  
Oxidative Cyclization ◽  
Environmentally Benign ◽  
Allylic Alcohols ◽  
Efficient Manner ◽  
Metal Free ◽  
Boronic Esters

A sustainable, environmentally benign electrochemical oxidative three-component cyclization of allylic alcohols, boronic acids, and dichalcogenides under metal-free and oxidant-free conditions has been developed, which provides an efficient manner for the...

The Use of Bitumen Linear Viscoelastic Properties to Assess Rutting Sensitivity

2014 ◽  
Vol 567 ◽  
pp. 755-762
Author(s):  
Salah E. Zoorob ◽  
Ibrahim B. Kamaruddin ◽  
Napiah Madzlan
Keyword(s):  
Energy Equation ◽  
Empirical Relationship ◽  
Stored Energy ◽  
Theoretical Derivation ◽  
The Us ◽  
Modified Binders ◽  
Recent Developments ◽  
Linear Viscoelastic ◽  
Modified Binder ◽  
Performance Grading

The use of viscosity temperature relationships to predict creep performance of road bitumens have been shown to be inadequate in particular with respect to the analysis of polymer modified binders. In this paper we explore the origins of the US Strategic Highway Research Programmebinder performance grading system and detail two examples of more recent developments towards improved creep characterisation.Starting from first principles, an equation to analyse the ratio of dissipated to stored energy during sinusoidal loading of viscoelastic bitumen was derived. The energy equation was contrasted with an empirical relationship proposed by Anderson D.A., and with a second more theoretical derivation proposed by Shenoy A.Using frequency sweep data from a conventional 40/50 pen grade bitumen and a proprietary SBS modified binder, the applicability of the energy equation was subsequently compared to the two aforementioned post-SHRP creep relations. Recommendations are made regarding the suitability of the proposed relations in ranking bitumen creep performance.

scholarly journals Should Women Consult Health Agencies in Matters of Birth Control and Contraception?

2020 ◽  
Vol 1 (2) ◽  
pp. 28-37
Author(s):  
Kraetschmer K
Keyword(s):  
Birth Control ◽  
Economic Perspective ◽  
Safety And Efficacy ◽  
Contraceptive Devices ◽  
Scholarly Publications ◽  
Health Agencies ◽  
The Us ◽  
Other Information ◽  
Recent Developments ◽  
Harmful Effects

Background and Aim: On the background of recent developments revealing the harmful effects of contraceptive devices which are recommended by health agencies the paper aims at analyzing publications and other information material emanating from these agencies. This analysis – guided by the bioethical principle of informed consent — focuses on flawed science, ambiguous language, and misleading data. Method and Material: The method consists of collecting and analyzing information provided by health agencies for consumers inquiring about the safety and efficacy of contraceptive products. The material comprises documents, charts, leaflets and other publications emanating from the most authoritative and most frequently consulted health agencies, in particular those active in the US and European countries. Results and Implications: As a result of the investigation women must be advised to consult only a selected number of health agencies, especially those which take into account findings of pharmacovigilance, pharmaceutical vigilance, and scholarly publications focusing on the safety of contraception. The implications from an economic perspective are the discontinuation of funding through taxpayer money for those health agencies which continue to disseminate flawed science and demonstrate incompetence in questions about the safety of contraception.

Russia: facing west or east

2017 ◽  
Author(s):  
Jude Woodward
Keyword(s):  
Foreign Policy ◽  
East Asia ◽  
21St Century ◽  
Us Foreign Policy ◽  
The West ◽  
Uncertain Outcome ◽  
Policy Goals ◽  
The Us ◽  
Recent Developments ◽  
Post War

This chapter reviews US-China-Russia relations in the post-war period, and considers how recent developments affect prospects for the US ‘pivot’. It explains why those driving US foreign policy towards China see the confrontation with Russia in Ukraine as a dangerous and diversionary adventure, leading to Sino-Russian convergence, distracting US attention from East Asia and undermining confidence among the US’s Asian allies of its commitment to the region. It is argued that if the US is to maintain primacy in the 21st century, it must subordinate other foreign policy goals to the paramount objective of containing China’s rise. The US’s failure to do this, instead pitting itself against both Putin in the West and China in the East, means it has driven Russia and China together, quite possibly sacrificing its vital need to contain China for a lesser goal of uncertain outcome in Ukraine.

scholarly journals Recent advances in synthetic biosafety

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2118 ◽  
Author(s):  
Anna J. Simon ◽  
Andrew D. Ellington
Keyword(s):  
Biomedical Applications ◽  
Environmental Pollutants ◽  
Industrial Applications ◽  
Environmentally Benign ◽  
Industrial Chemicals ◽  
Recent Advances ◽  
Modern Development ◽  
Benign Synthesis ◽  
Recent Developments ◽  
Synthetic Organisms

Synthetically engineered organisms hold promise for a broad range of medical, environmental, and industrial applications. Organisms can potentially be designed, for example, for the inexpensive and environmentally benign synthesis of pharmaceuticals and industrial chemicals, for the cleanup of environmental pollutants, and potentially even for biomedical applications such as the targeting of specific diseases or tissues. However, the use of synthetically engineered organisms comes with several reasonable safety concerns, one of which is that the organisms or their genes could escape their intended habitats and cause environmental disruption. Here we review key recent developments in this emerging field of synthetic biocontainment and discuss further developments that might be necessary for the widespread use of synthetic organisms. Specifically, we discuss the history and modern development of three strategies for the containment of synthetic microbes: addiction to an exogenously supplied ligand; self-killing outside of a designated environment; and self-destroying encoded DNA circuitry outside of a designated environment.

Combination Drug Therapy: A Strategy for Aggressive Lipid Modification

2005 ◽  
Vol 40 (11) ◽  
pp. 954-962
Author(s):  
James M. Backes ◽  
Patricia A. Howard
Keyword(s):  
Cardiovascular Disease ◽  
Drug Therapy ◽  
Clinical Outcome ◽  
Combination Drug Therapy ◽  
Lipid Modification ◽  
Combination Drug ◽  
Cardiovascular Pharmacotherapy ◽  
The Us ◽  
Prevention And Treatment ◽  
Recent Developments

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the US, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on prevention and treatment — if they keep current with developments in drug therapy.

The Evolving Role of Angiotensin Receptor Blockers in Heart Failure

2002 ◽  
Vol 37 (5) ◽  
pp. 474-482
Author(s):  
Patricia A. Howard
Keyword(s):  
Heart Failure ◽  
Cardiovascular Disease ◽  
Angiotensin Receptor Blockers ◽  
Angiotensin Receptor ◽  
Cardiovascular Pharmacotherapy ◽  
The Us ◽  
Prevention And Treatment ◽  
Recent Developments ◽  
Receptor Blockers

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the US, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on the prevention and treatment of cardiovascular disease—if they keep current with developments in drug therapy.

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