Dehydrooligopeptides. V. Synthesis of N-carboxy .ALPHA.-dehydroamino acid anhydrides and their transformation to .ALPHA.-dehydroamino acid and dehydrooligopeptide derivatives.
The synthesis of N-carboxy α-dehydroamino acid anhydrides (ΔNCA) from benzyloxycarbonyl-α-dehydroamino acids and the subsequent conversion of these products into new α-dehydroamino acid and dehydrooligopeptide derivatives are described. It was found that the new ΔNCA derivatives were very useful synthons for dehydropeptides. The racemization behavior and configurational determination of all the new dehydrooligopeptides thus obtained are discussed.
The reaction of N,N-dimethyl- or N,N-pentamethylene-formamide chlorides with n-butyl, cyclohexyl, and 2,4-xylyl isocyanides results in the formation of 1:2-adducts which are readily converted by water to N,N'-disubstituted α-(dialkylamino)malonamides. In the case of N,N-dimethylamide chlorides of acetic, propionic, and benzoic acids, the products are the corresponding N-substituted α-ketoamides resulting
An efficient and chemoselective C(sp(2))-N bond cleavage of aromatic imidazo[1,2-a]pyridine molecules is developed. A broad scope of amide compounds such as alpha-ketoamides and N-(pyridin-2-yl)arylamides are afforded as the final products in up to quantitative yields. Diverse C-N bond cleavages are controlled by the oxidative species used in this transformation, with various amide products afforded in a chemoselective fashion. A preliminary study indicated that some alpha-ketoamides exhibit anti-Tobacco Mosaic Virus activity for potential use in plant protection.