Amides amidinium salt synthesis

Without additional reagents Synthesis of carboxylic acid amides from ketene aminals via amidinium salts... 

Another formal synthesis of (5 ,9. -(—)-indolizidine 223AB (1780), by Charette and colleagues, employed a valine-derived auxiliary as an amide-containing appendage in the pyridine (—)-1788 in order to control absolute stereochemistry (Scheme 225). An unusual cyclization mediated by trifluor-omethanesulfonic anhydride followed by addition ofpropylmagnesium chloride afforded the (fo)-bicyclic amidine (—)-1789. Diastereoselective hydrogenation over palladium on carbon produced the saturated indolizidine (—)-1790, which was alkylated with iodomethane to give the amidinium salt... 

L-Alanyl glycine nitrile (96) can be prepared from the protected dipeptide (94) via the amide (95) (Scheme 146). Nitrile (96) affords the amidinium bis(tosylate) (97), a key precursor in the synthesis of poly(dipeptamidinium) salts, of interest in view of their constitutional relation to polynucleotides. 

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