Synthesis and Characterization of α,β-Unsaturated Hydroximoyl Chlorides and Hydroximates

Abstract

New α,β-unsaturated hydroximoyl chlorides (PhC(Cl)=CHC(Cl)=NOCH3) and hydroximates (PhC(OCH3)=CHC(OCH3)=NOCH3) were prepared. The ZZ-isomer of PhC(Cl)=CHC(Cl)=NOCH3 was prepared in four steps from ethyl benzoylacetate. Ultraviolet irradiation of the ZZ-isomer gives a mixture of all four possible isomers. Sodium methoxide was reacted with these isomers to determine the configuration about the carbon–carbon double bond for each. The Z-isomers reacted with sodium methoxide to give the corresponding alkyne by elimination whereas the E-isomers gave the substitution product. The configuration about the carbon–nitrogen double bond was determined from the 1H NMR chemical shift of the NOCH3 group.