New method for producing 'libraries' of important carbohydrate molecules

New method for producing 'libraries' of important carbohydrate molecules

Complex organic molecules speed development of new drugs

Complex organic molecules speed development of new drugs

Scripps Research Team Wins Global Race To Achieve Landmark Synthesis Of Perplexing Natural Product

Scripps Research Team Wins Global Race To Achieve Landmark Synthesis Of Perplexing Natural Product

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Tamiflu starting from D-ribose an efficient inexpensive method....

We know the recent hue and cry about the stock piling of Tamiflu (Oseltamivir) and there by the deficiency of the drug. The commercially (see the below scheme; source : wikipedia) used method i.e., Karpf / Trussardi synthesis make use of  Shikimic acid. Many researchers have tried alternative raw materials for the synthesis of the drug and are successful also (see other schemes).

Now Anqi Chen and Christina  Chai of Shionogi & Co., Ltd have come up with a new process for making the drug that does not use shikimic acid. They found that D-ribose, a naturally-occurring sugar produced by fermentation in large scales, potentially provides an inexpensive and abundant source of starting material for making the drug. D-ribose costs only about one-sixth as much as shikimic acid. In lab studies, the scientists demonstrated the potential use of D-ribose as an alternative source for the synthesis of Tamiflu.

As per the claim by the authors, the concise alternative route  (12 steps) does not utilize protecting groups and features the introduction of 3-pentylidene ketal as the latent 3-pentyl ether, the use of a highly efficient RCM reaction to form the Tamiflu skeleton, and selective functional group manipulations (see Scheme 2, source : Organic Letters)

Ref : http://pubs.acs.org/doi/abs/10.1021/ol9024716

Improved recipe for catalysts

Improved recipe for catalysts

Olefination of arenes via palladium-catalysed Mizoroki-Heck reaction...

Olefination of arenes is challenging because there are a number of positions on the aromatic ring to which the olefin can attach and there by leading to different isomers. One way is to follow the Heck reaction. The main criteria required for this reaction is that, the target carbon of the ring to be halogenated. And as synthetic chemists we know how tricky to get the halogenated compounds and that is why this reaction has limited applications. Its interesting to note that researchers from Scripps Research Institute have come with a novel procedure, where in there is no compulsion of halogenated compound.

As per the claim by the authors, the procedure is operationally simple, economical. The presence of a carboxyl group adjacent to the target C-H on the ring results in a phenomenon called the complex-induced proximity effect, which pulls the catalyst towards the relevant bond. In cases where the two ortho positions are equivalent, this approach alone can result in good yields of the desired product. When the substituents are different, the selectivity has been achieved by the use of amino acid-derived ligands between sterically and electronically similar ortho positions - which is really interesting...

http://www.rsc.org/chemistryworld/News/2009/November/27110902.asp

Cambrex wins the CPhI Innovation Award for its Continuous-Flow Microwave-Assisted Organic Synthesis technology

Cambrex wins the CPhI Innovation Award for its Continuous-Flow Microwave-Assisted Organic Synthesis technology