Issue 33 January 2010

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A two-step, three-enzyme process for the synthesis of a key intermediate of atorvastatin, the active ingredient in Lipitor®, has recently been reported by scientists at Codexis in conjunction with Roger Sheldon at University of Delft, Netherlands.

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α-Arylated carbonyl compounds are commonly occurring motifs in biologically interesting molecules. Conventional procedures for their synthesis often result in complications, particularly in scale-up (stoichiometric amounts of reagents; harsh reaction conditions etc).

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T3P® is a commonly used coupling reagent and water scavenger for peptide synthesis but new applications are being found. The reagent offers advantages of low toxicity, broad functional-group tolerance, low epimerisation tendency and easy aqueous work-up in many dehydration reactions.

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Chemists from Taiwan have developed a relatively simple method of reductive coupling of nitriles with acrylamides in the presence of a cobalt catalyst and zinc/zinc iodide, in water .....

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Scientists at Genentech, San Francisco, have recently reported a synthesis of triazoles that relies initially on a carbonylation of aromatic halides with CO and an amidine, the intermediate then being trapped by a hydrazine.

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A recent paper from workers at GSK describes improvements to the synthesis of Denagliptin (12). The final chemical step is Boc deprotection of (11) with p-toluenesulphonic acid (p-TSA) in isopropanol (IPA). Some isolated batches of final product contained impurities 12A (~1%), 12B (~1%), and 12C (~0.3%).

Chemoselective Hydrogenation

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I was intrigued by a report by Kathlyn Parker et al where they describe a selective reduction of a propargylic alcohol in the presence of a vinyl halide ...

Enantioselective Conjugate Reduction

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This process brings together several interesting facets; organocatalytic process, enantioselective, use of a Hantzsch diester for hydrogen source ...

Oxindoles with Chiral Quarternary Carbon via Hetero-Claisen Chemistry

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An area of chemistry I have found interesting for many years now is the use of sigmatropic rearrangements since they can result in high degree of chemo- and stereoselectivity...