A practical synthesis of a tripeptide containing a ketomethylene isostere, suitably protected for introduction in Fmoc SPPS, has been carried out for the first time in Fmoc chemistry by using a modified Dakin-West reaction. In recent years, the use of peptides bearing modified isostere amide bond has been more and more widespread in the study of biological systems as enzymes and receptors.1 Amo...

A series of previously unavailable derivatives of 2-alkyl- and 2-benzylderivatives of oxazolo[3,2-a]pyridines III were obtained via tandem ring opening and ring closure from stable mesoionic 3-acyloxazolo[3,2-a]pyridinium-2-olates I. The key intermediates of this tandem transformation are N-(b-oxoethyl)pyridones-2 II obtained by Dakin-West acylation of (pyridone-2-yl-1)acetic acid. An example o...

A series of previously unavailable derivatives of 2-alkyland 2-benzylderivatives of oxazolo[3,2-a]pyridines III were obtained via tandem ring opening and ring closure from stable mesoionic 3-acyloxazolo[3,2-a]pyridinium-2-olates I. The key intermediates of this tandem transformation are N-(b-oxoethyl)pyridones-2 II obtained by Dakin-West acylation of (pyridone-2-yl-1)acetic acid. An example of ...

In a previous communication I we reported on the action of weak and of stronger alkali on dextro-alanyl-dextro-alanine anhydride. I t was observed that the anhydride was partially racemized if it was allowed to remain in an aqueous solution containing one equivalent of sodium hydroxide for 24 hours. When the concentration of the alkali was increased tenfold, the anhydride was rapidly converted ...