Alkyl halides, from imidoyl halide

Imidoyl halides react with NH- and NHa-containing compounds to give amidinium salts, which were sometimes isolated,but the hree amidine bases were usually prepared from them. Since amid-ines are converted by water-free acids to the corresponding amidinium salts, amidinium salts with nearly every desired anion are accessible by this procedure. The alkylation of A/A(, -trisubstituted amidines, as well as those of symmetrically IV.lV -disubstituted, IV-monosubstituted and A(-unsubstituted amidines are unambigous reactions. By this method a lot of amidinium salts, e.g. (145), (146) and (147) (equation 87), have been prepared. The alkylation of A -monosubstituted and N,Ar-unsymmetrrcally substituted amidines can give rise to product mixtures of amidinium salts. 

The NMR spectra of imidoyl halides are not too well investigated. We have utilized NMR spectroscopy to elucidate the structure of arylsulfonyl-chloroformamidines ( ), but no data with regard to the chemical shift of alkyl groups attached to the carbon or nitrogen atom of the —C(X)=N— system is available. Of course, differentiation of the imidoyl halide structure in a-hydrogen containing compounds from the corresponding tautomeric enamine structures is easily accomplished by NMR spectroscopy, provided that the system contains olefinic protons. 

Among other reactions, the bis-metallated species (151) derived from nitroalkanes condense with dialkyl carbonates to give comp>ounds (152), in 60—80% yield, which can serve as precursors of both a-amino-acids and a-hydroxyamino-esters as well as a-keto-esters. Oxazolin-5-ones (153) can be alkylated at the 4-position by alkyl halides in hot DMF containing HMPA and ethyldi-isopropylamine. Yields are good (60—90%) for allylic, benzylic, and propargylic halides but otherwise poor (e.g. 32% with EtI) under these conditions acid hydrolysis of the products affords substituted a-amino-acids. Mesoionic l,3-oxazol-5-ones (154), obtained from imidoyl chlorides and acyl-tetracarbonylferrates, react with alcohols to give N-acyl-a-amino-acid esters. ... 

---