Green Chemistry Blog

“All-water” chemistry for synthesis of N-arylmethyl-2-substituted benzimidazoles

06 Nov 2012

Scientists from India have developed a tandem N-alkylation-reduction-condensation route to synthesize N-arylmethyl-2-substituted benzimidazoles.

1,2-Disubstituted benzimidazoles exhibit a broad range of biological activities, which make them a very popular synthetic target. The regio-specific synthesis of these compounds is the main synthetic challenge, with the desired regioselectivity of the final compounds determined at the aryl-amination stage. However, this traditionally requires a transition metal catalyst, expensive ligands and an appropriate base.

In this work, Asit Chakraborti and colleagues from the National Institute of Pharmaceutical Education and Research, Punjab, India, present a one-pot strategy to produce N-arylmethyl-2-substituted benzimidazoles in water. The procedure does not require a transition metal catalyst or base, with water directing the regioselectivity of the reaction through hydrogen bond mediated ‘electrophile-nucleophile dual activation’.

Read the full article for free until the 4th December 2012!

“All-water” chemistry of tandem N-alkylation–reduction–condensation for synthesis of N-arylmethyl-2-substituted benzimidazoles, Damodara N. Kommi, Dinesh Kumar, Rohit Bansal, Rajesh Chebolu and Asit K. Chakraborti, Green Chem., 2012, DOI: 10.1039/C2GC36377A

You may also be interested in this article as well – free to access for two weeks:

Catalytic procedures for multicomponent synthesis of imidazoles: selectivity control during the competitive formation of tri- and tetrasubstituted imidazoles, Dinesh Kumar, Damodara N. Kommi, Narendra Bollineni, Alpesh R. Patel and Asit K. Chakraborti, Green Chem., 2012, 14, 2038-2049

Stay up-to-date with the latest news and content in Green Chemistry by registering for our free table of contents alerts.

Comments Off on “All-water” chemistry for synthesis of N-arylmethyl-2-substituted benzimidazoles

Selective oxidation of alcohols and aldehydes over supported metal nanoparticles

31 Oct 2012

By Mary Badcock, Deputy Editor.

Oxidation represents one of the most important reactions in organic synthesis and looks to have a significant role on the development and synthesis of value-added chemicals from biomass. Efforts to make oxidation reactions more sustainable have led to the development of heterogeneous catalysts and the use of molecular oxygen an alternative to traditional, toxic chemical oxidants.

In this Critical Review, Robert Davis and colleagues from the University of Virginia, USA, evaluate the literature surrounding the use of supported metal nanoparticle catalysts for the selective oxidation of alcohols and aldehydes. Davis compares the performances of the catalysts studied in this review by categorising reaction rates based on the turnover frequency as a common, consistent denominator. The authors also look at factors that can affect the evaluation of reaction kinetics, such as catalyst deactivation, and give suggestions regarding how to obtain the best data.

Read this article for free until the 29th November 2012!

Selective oxidation of alcohols and aldehydes over supported metal nanoparticles, Sara E. Davis, Matthew S. Ide and Robert J. Davis, Green Chem., 2012, DOI: 10.1039/C2GC36441G

You may also be interested in these related articles – free to access until the 15th November 2012:

On the mechanism of selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over supported Pt and Au catalysts, Sara E. Davis, Bhushan N. Zope and Robert J. Davis, Green Chem., 2012, 14, 143-147

Inhibition of gold and platinum catalysts by reactive intermediates produced in the selective oxidation of alcohols in liquid water, Bhushan N. Zope and Robert J. Davis, Green Chem., 2011, 13, 3484-3491

Stay up-to-date with the latest news and content in Green Chemistry by registering for our free table of contents alerts.

Comments Off on Selective oxidation of alcohols and aldehydes over supported metal nanoparticles

Green Solvents for Synthesis 2012

27 Oct 2012

By Mary Badcock, Deputy Editor.

Sarah Ruthven, Editor of Green Chemistry, attended the 2012 Green Solvents for Synthesis Conference, held from the 8th-10th October 2012 in Boppard, Germany. The theme of this year’s installment of the biennial conference series was Advanced Concepts for Solution Phase Chemistry and Processes.

Professor Walter Leitner, Chair of the Green Chemistry Editorial Board, was Chairman of the organising committee, which also included Advisory Board members Professor Kenneth Seddon and Professor Peter Wasserscheid.

The focus of the conference was centre around energy-efficient processes, selectivity control for waste prevention, alternative and efficient use of raw materials, activation and capture of CO₂and integrated reaction and separation processes. The 3-day programme included 12 Keynote lectures delivered by internationally renowned experts and a poster session, where three of the top posters were awarded with prizes by the organising committee. One of these prizes was sponsored by Green Chemistry, and the recipient of was Mr Victor López-López for his poster on “Energy-efficient CO2-capture with solutions based on ionic liquids” (pictured second from the left). He was awarded with a certificate and a copy of Sustainable Solutions for Modern Economies.

Many congratulations to Victor on receiving this prize.

Comments Off on Green Solvents for Synthesis 2012

Issue 11 of Green Chemistry now online

25 Oct 2012

By Mary Badcock, Deputy Editor.

The latest issue of Green Chemistry is now available to read online!

Green Chemistry, issue 11, 2012, front cover The front cover of issue 11 of Green Chemistry features work my Pedro Lozano and colleagues from the University of Murcia, Spain, who report a clean bio-catalytic route to flavour esters. The team used switchable ionic liquid/solid phases as the reaction/separation media to achieve this, whereby a fully homogeneous liquid phase could be achieved at 50 °C and a solid-phase system could be created at room temperature. This allows the enzyme to function in the ionic liquid at temperatures compatible for enzyme catalysis, in this case giving almost 100% yields of flavour esters at 50 °C. By cooling and subsequent centrifugation, the liquid, almost pure, reaction product could be easily separated off leaving the biocatalyst/ionic liquid system in place which can then be reused for multiple cycles.

A clean enzymatic process for producing flavour esters by direct esterification in switchable ionic liquid/solid phases, Pedro Lozano, Juana M. Bernal and Alicia Navarro, Green Chem., 2012, 14, 3026-3033

The inside front cover of the issue features work by Joshua Taygerly, Emily Peterson and colleagues from Amgen Inc. and Northeastern University, USA, who have developed a guide which aims to help synthetic chemists find suitable and more environmentally friendly alternatives to a DCM-solvent system for chromatographic purification of compounds. The authors selected several ‘drug-like’ molecules which reflected the types of molecules regularly prepared and purified, tested several alternative solvent systems to DCM. From the results, they assembled a figure which allows the scientist to find the potentially equivalent, alternative system(s). The primary use of this guide is to provide chemists with a quickly identifiable starting point for selecting alternative solvent systems to DCM.

A convenient guide to help select replacement solvents for dichloromethane in chromatography, Joshua P. Taygerly, Larry M. Miller, Alicia Yee and Emily A. Peterson, Green Chem., 2012, 14, 3020-3025

These articles are free to access for 6 weeks!

You can also read Pedro Lozano’s recent interview with Green Chemistry here.

Stay up-to-date with the latest news and content in Green Chemistry by registering for our free table of contents alerts.

Comments Off on Issue 11 of Green Chemistry now online

Meet our Authors: Ken-ichi Shimizu

19 Oct 2012

By Mary Badcock, Deputy Editor.

Ken-ichi Shimizu is an Associate Professor of Catalysis Research Center at Hokkaido University, Japan. His research projects focus on heterogeneous catalysis for green organic reactions and automotive emission control. Ken-ichi kindly spared Green Chemistry a few moments to talk about his work…

Who or what initially inspired you to become a chemist?

In my childhood and youth I would see my father working as an eel farmer in front of my house. Farming is a kind of empirical science for improvement of the yield and quality of the products, and a working hypothesis is refined by the accumulation of empirical facts. Until I reached undergraduate level, chemistry was not a very attractive subject for me because I could not find the concept of hypothesis in the textbook. During my master and doctoral works at Nagoya University, I discovered experimental chemistry in the field of heterogeneous catalysis. Discussions with my supervisors and students as well as the accumulation of empirical facts lead to correction or revision of the hypothesis of reaction mechanism. This experience made me a chemist.

What was the motivation behind the research described in your recent Green Chemistry article? (Green Chem., 2012, 14, 984-991)

Click here to read the full interview…

Comments Off on Meet our Authors: Ken-ichi Shimizu

Professor Joan Brennecke elected to the National Academy of Engineering

16 Oct 2012

By Mary Badcock, Deputy Editor.

Green Chemistry Advisory Board member Joan Brennecke, the Keating-Crawford Professor of Chemical and Biomolecular Engineering at the University of Notre Dame, USA, has been elected a member of the National Academy of Engineering. This honour has been awarded “for innovation in the use of ionic liquids and supercritical fluids for environmentally benign chemical processing.”

Election to the National Academy of Engineering is one of the highest professional distinctions that can be awarded to an engineer. An Academy membership honours those who have made outstanding contributions to engineering research, practice or education.

Green Chemistry would like to extend our warmest congratulations to Professor Brennecke on this achievement.

Comments Off on Professor Joan Brennecke elected to the National Academy of Engineering

From Waste to Wealth Using Green Chemistry

11 Oct 2012

By Mary Badcock, Deputy Editor.

On Thursday the 27th September, Professor James Clark from the University of York, UK, gave a public lecture at The Chemistry Centre in London on “From Waste to Wealth using Green Chemistry“.

The world today faces the fundamental issues of increasing waste but decreasing resources as it tries to cope with the ever increasing consumption of a growing population. Many of the raw resources and elements needed for the manufacture of important products used everyday are now running out. For example, in our search for ‘carbon-free’ products we have then created additional problems by significantly depleting the world’s resource of other elements, such as germanium. We generate so much waste, but what do we do with it? How can we deal with our waste more efficiently?

The only way these problems can be met and dealt with is through a fundamentally different approach to the way we consume resources. Professor Clark’s lecture shows how by considering our waste as an opportunity rather than a problem, we can fully move towards a truly sustainable resource consumption model and give our children some hope for the future.

The event, sponsored by GlaxoSmithKline, was strongly attended by an audience of 100 people from a broad range of different backgrounds. The event generated lots of questions and some lively debates which continued long after the lecture had ended.

Missed the lecture? You can watch Professor Clark’s lecture in full on The Reaction website!

Professor Clark is the founding Editor of Green Chemistry and is also one of the Editors of the RSC Green Chemistry Book Series – find out more here.

You may also be interested in a few of Professor Clark’s recent Green Chemistry articles – free to access until the 9th November 2012:

Preparation and characterisation of bioplastics made from cottonseed protein, H.-B. Yue, Y.-D. Cui, P. S. Shuttleworth and James H. Clark, Green Chem., 2012, 14, 2009-2016

Thermosetting resin based on epoxidised linseed oil and bio-derived crosslinker, Nontipa Supanchaiyamat, Peter S. Shuttleworth, Andrew J. Hunt, James H. Clark and Avtar S. Matharu, Green Chem., 2012, 14, 1759-1765

A quantitative comparison between conventional and bio-derived solvents from citrus waste in esterification and amidation kinetic studies, James H. Clark, Duncan J. Macquarrie and James Sherwood, Green Chem., 2012, 14, 90-93

Switchable adhesives for carpet tiles: a major breakthrough in sustainable flooring, Peter S. Shuttleworth, James H. Clark, Robert Mantle and Nigel Stansfield, Green Chem., 2010, 12, 798-803

Comments Off on From Waste to Wealth Using Green Chemistry

Biocatalysis: an article collection

08 Oct 2012

By Mary Badcock, Deputy Editor.

A collection of high impact articles focusing on biocatalysis, from the RSC’s Catalysis Science & Technology, Green Chemistry, RSC Advances, Organic & Biomolecular Chemistry (OBC) and ChemComm

Beers, wines and cheeses are enjoyed around the world today and have been for millennia. In fact the practices of brewing and cheese-making pre-date recorded history so it is difficult to accurately determine when we first started using naturally occurring enzymes and microorganisms to create valuable (and in this case, tastier!) products.

Biocatalysts are of course used in far more diverse applications than the creation of food-stuffs, including in many organic syntheses and in the generation of fine chemicals. Due to their natural design, they can offer superior selectivity for particular products and have a far lower environmental impact than many traditional catalysts. Our knowledge and understanding of biocatalysts has increased dramatically in the last few decades, which has allowed us to develop biologically modified and biomimetic catalysts for a range of applications.

To keep you up to date with the latest advances in this rapidly expanding field we have collected together these high impact articles and made them free to access until the 31^st October!

Click here for the full list of free articles

Comments Off on Biocatalysis: an article collection

Low melting mixtures in organic synthesis – an alternative to ionic liquids?

05 Oct 2012

By Mary Badcock, Deputy Editor.

One of the major topics within the green and sustainable chemistry field is replacing hazardous and/or harmful solvents with more environmentally friendly alternatives. One group of solvents that have been investigated for this purpose over recent years are ionic liquids. However, it is now felt that not all ionic liquids can be classified as ‘green’ and that their environmental impact is strongly dependent on the cation and anion used to make them. Natural compounds can be used to produce deep eutectic solvents, sugar melts or ionic liquids, generating a reaction media which combines the advantages of non-toxic and biodegradable starting materiuals with the physicochemical properties of ionic liquids.

In this Critical Review, Burkhard König and Carolin Ruß from the University of Regensburg, Germany look at the impact these low melting mixtures have had on organic synthesis and their various applications. The authors show that experimental and theoretical determinaton of the molecular structure of these solvents is needed in order to understand how this shapes their physcial properties. Given the huge number of naturally occuring anions and cations, there remains an enormous range combinations to investigate with the potential to produce low-environmental impact solvents with tailor-made properties.

Read the full article for free until the 5th November 2012!

Low melting mixtures in organic synthesis – an alternative to ionic liquids? Carolin Ruß and Burkhard König, Green Chem., 2012, DOI: 10.1039/C2GC36005E

Comments Off on Low melting mixtures in organic synthesis – an alternative to ionic liquids?

Green Chemistry Blog

“All-water” chemistry for synthesis of N-arylmethyl-2-substituted benzimidazoles

Top ten most accessed articles in September

Selective oxidation of alcohols and aldehydes over supported metal nanoparticles

Green Solvents for Synthesis 2012

Issue 11 of Green Chemistry now online

Meet our Authors: Ken-ichi Shimizu

Professor Joan Brennecke elected to the National Academy of Engineering

From Waste to Wealth Using Green Chemistry

Biocatalysis: an article collection

Low melting mixtures in organic synthesis – an alternative to ionic liquids?

Links

Categories

Archives

Meta