Hot articles – Page 18 – Organic & Biomolecular Chemistry Blog

Archive for the ‘Hot articles’ Category

Issue 5 just published – gold-mediated modification of oligosaccharides and easy access to cinnamonitriles on the covers

13 Jan 2012

On the outside front cover a communication from Chi-Ming Che and Man-Kin Wong et al. is highlighted, showing their method for gold-mediated bifunctional modification of oligosaccharides via a three-component coupling reaction.

Gold-mediated bifunctional modification of oligosaccharides via a three-component coupling reaction
Karen Ka-Yan Kung, Gai-Li Li, Lan Zou, Hiu-Chi Chong, Yun-Chung Leung, Ka-Hing Wong, Vanessa Kar-Yan Lo, Chi-Ming Che and Man-Kin Wong
DOI: 10.1039/C1OB06429K

On the inside front cover is an article from Brindaban C. Ranu et al. on copper catalysed cyanation of styrenyl bromides to give functionalized cinnamonitriles with preserved stereochemistry.

Hydroxyapatite-supported Cu(I)-catalysed cyanation of styrenyl bromides with K4[Fe(CN)6]: an easy access to cinnamonitriles
Debasree Saha, Laksmikanta Adak, M. Mukherjee and Brindaban C. Ranu
DOI: 10.1039/C1OB06467C

View the rest of the issue including a review on squaraine dyes in photodynamic therapy

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Hot article on intramolecular Prins cyclization of benzyl ethers to give novel dioxabicycles and oxatricycles

12 Jan 2012

B. V. Subba Reddy et al. report the stereoselective synthesis of cis– and trans-fused bicyclic and tricyclic tetrahydropyran scaffolds. Their method involves DDQ oxidation to activate the benzylic C-H of various benzyl ethers and subsequent intramolecular Prins cyclization to give the dioxa-bicycles and oxatricycles.

Read the details for free for the next 4 weeks…..

Oxidative Prins and Prins/Friedel–Crafts cyclizations for the stereoselective synthesis of dioxabicycles and hexahydro-1H-benzo[f]isochromenes via the benzylic C–H activation
B. V. Subba Reddy, Prashant Borkar, J. S. Yadav, P. Purushotham Reddy, A. C. Kunwar, B. Sridhar and René Grée
DOI: 10.1039/C1OB06489D

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HOT: Aquafoldamers as synthetic water channels

11 Jan 2012

In this OBC Hot Paper Huaqiang Zeng and coworkers at the National University of Singapore have studied a series of water-binding aquafoldamers, illustrating their potential use for recognizing larger water clusters of diverse topologies and as synthetic water channels.

Read for free…
This article is part of our forthcoming themed issue on Foldamer Chemistry – visit this page to see the collection of articles grow.

Reference:
Synthesis, structural investigation and computational modelling of water-binding aquafoldamers
Huaiqing Zhao, Wei Qiang Ong, Xiao Fang, Feng Zhou, Meng Ni Hii, Sam Fong Yau Li, Haibin Su and Huaqiang Zeng
Org. Biomol. Chem., 2012, Advance Article
DOI: 10.1039/C1OB06609A

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Hot article on the synthesis of heparin oligosaccharides and the inhibition of eosinophil-derived neurotoxin binding

11 Jan 2012

In this hot article Shang-Cheng Hung et al have devised a synthetic route to heparin oligosaccharides from cheap D-glucosamine and diacetone α-D-glucose starting materials. Heparin is a widely used anticoagulant, but homogeneous heparin oligosaccharides are difficult to obtain naturally and synthetic access is required. This article describes routes to tri-, penta- and heptasaccharides which are able to inhibit eosinophil-derived neurotoxin, a protein with ribonuclease activity that is released as part of the immune response to allergic inflammation e.g. in asthma.

Hot article on the 3-way DNA junction as a scaffold for chromophore assemblies

04 Jan 2012

The naturally occurring 3-way junction formed at the branch point of three DNA or RNA strands is a useful structure for organising functional molecules. In this hot paper Markus Probst et al. have used the three-way junction to assemble non-nucleosidic alkynylpyrene and perylenediimide chromophores at the branch point area. The spectroscopic properties of the chromophores can be modified depending on the composition of the DNA junction, ranging from monomer or excimer fluorescence to complete quenching, demonstrating the potential of such assemblies for use in diagnostic, electronic, optical and mechanical applications

Squaraine dyes for photodynamic therapy: reviewing the latest developments

21 Dec 2011

Following our latest OBC Hot Article by Prof. Bradley D. Smith (available here), Squaraines are in the spotlight again in this review article by Danaboyina Ramaiah et al..

The Perspective highlights the recent developments of squaraines as PDT sensitizers, including:

Design principles
Squaraines as singlet oxygen generators
Squaraines as two-photon absorbing agents
Carrier systems for squaraine dyes
In vitro and in vivo studies of squaraine-PDT action

Timely and HOT, why not read this Perspective now – it will be FREE to access for the next 4 weeks

Squaraine dyes in PDT: from basic design to in vivo demonstration
Rekha R. Avirah, Dhanya T. Jayaram, Nagappanpillai Adarsh and Danaboyina Ramaiah
Org. Biomol. Chem., 2012, Advance Article
DOI: 10.1039/C1OB06588B, Perspective

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Deep-red fluorescent, water-soluble, with rapid renal clearance…?

20 Dec 2011

Prof. Bradley D. Smith and coworkers at University of Notre Dame and Molecular Targeting Technologies, Inc. have modified squaraine rotaxanes with four large stopper groups that provide the much needed long-term, chemical stability in physiological solution. Combined with high quantum yields, excellent excitation/emission wavelength for in vivo analysis, good water-solubility, some of these new dyes undergo rapid renal clearance and very low tissue uptake in living mice, making them excellent fluorescent tracers.

As noted by the authors, the dendritic and polyionic structures of these dyes will also interest and inform the community of scientists who are trying to develop compounds that do not interact with biological surfaces.

A simple and novel approach – Read all the details here – This Hot Article will be free to access for the next 4 weeks

Water-soluble, deep-red fluorescent squaraine rotaxanes
Erin L. Cole, Easwaran Arunkumar, Shuzhang Xiao, Bryan A. Smith and Bradley D. Smith
Org. Biomol. Chem., 2012, Advance Article
DOI: 10.1039/C2OB06783H, Communication

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HOT: urea synthesis from titanium imido complexes using carbon dioxide as a reagent

19 Dec 2011

CO₂ is an attractive alternative feedstock to oil for the fine chemicals industry, due to its abundance and the fact that it is a waste product in many other industrial processes. But carbon dioxide’s inertness makes it difficult to realistically use as a C-1 reagent. In this hot paper Jim Anderson and Rafael Bou Moreno from UCL report advances towards the green dream by synthesising ureas from the reaction of CO₂ with 12- and 14-electron titanium imido complexes.

Download the paper for all the details – it’s free to access for 4 weeks:

Synthesis of ureas from titanium imido complexes using CO₂ as a C-1 reagent at ambient temperature and pressure
James C. Anderson and Rafael Bou Moreno
DOI: 10.1039/C1OB06576A

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HOT: Thiophosphonoacetate-modified oligoribonucleotides with RNA therapeutics in sight

16 Dec 2011

The groups of Marvin Caruthers (University of Colorado at Boulder, USA) and Michael Gait (Medical Research Council Centre, Cambridge, UK) describe a new chemical synthesis and biological properties of 2’-O-methyl oligoribonucleotides (ORNs) containing internucleotide linkages modified with phosphonoacetate (PACE) and thiophosphonoacetate (thioPACE) groups.

ThioPACE modifications were found to greatly improve the efficiency of cell uptake and the potency of a 2′-O-Me-ORN miRNA122 inhibitor, showing that this class of modifications has great potential for applications in RNA therapeutics research.

As with all our HOT Articles, this OBC article is FREE for you to access, for a period of 4 weeks.

Synthesis and biological activity of phosphonoacetate- and thiophosphonoacetate-modified 2′-O-methyl oligoribonucleotides
Richard N. Threlfall, Adrian G. Torres, Angelika Krivenko, Michael J. Gait and Marvin H. Caruthers
Org. Biomol. Chem., 2012, Advance Article
DOI: 10.1039/C1OB06614E

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Hot emerging area: Transition metal-catalysed (4 + 3) cycloaddition reactions involving allyl cations

14 Dec 2011

Israel Fernández and José Luis Mascareñas review novel intramolecular (4 +3)-cycloaddition reactions of allenedienes in this Emerging Area article, focussing on recent examples where the allene acts as an allylic-cation surrogate. These methodologies overcome problems with previous strategies involving unstable allyl cation precursors or the need for stoichiometric activators and conformationally restricted dienes.

Areas covered include:

(4 + 3)-Cycloaddition reactions mediated by platinum(II) and gold(I) complexes
Aromaticity in the (4 + 3)-cycloaddition
Concerted vs. stepwise reaction mechanisms

As with all our hot research, this article will be free to access for 4 weeks – so take a look today:

Transition metal-catalysed (4 + 3) cycloaddition reactions involving allyl cations
Israel Fernández and José Luis Mascareñas
DOI: 10.1039/C1OB06604H

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