Electroreduction of (1<Emphasis Type="Italic">S,2S</Emphasis>)-2-amino-1-(4-nitrophenyl)-propane-1,3-diol derivatives. Behaviour of electrogenerated species and applications to organic synthesis

Hydroxylamines electrogenerated from (1S,2S)-2-amino-1-(4-nitrophenyl)-propane-1,3-diol derivatives (derivatives of p-nitrophenylserinol) are unstable in methanol–acetate buffer and practically stable in acetonitrile–aqueous acetate buffer. This latter medium was used to carry out subsequent reactions in situ involving the triacetylated p-hydroxylaminophenylserinol and various reagents. An azoxy compound was the major product isolated after reaction with maleic or phthalic anhydrides. In contrast, a benzoxazine dione was normally obtained with phthaloyl dichloride and a N-sulphonylated hydroxylamine was produced with p-toluenesulphonyl chloride.     

Electrosynthesis of nitroso compounds from (<Emphasis Type="Italic">1</Emphasis><Emphasis Type="Bold">S</Emphasis>, <Emphasis Type="Italic">2</Emphasis><Emphasis Type="Bold">S</Emphasis>)-2-amino-l-(4-nitrophenyl)-propane-1,3-diol derivatives

Nitroso compounds were electrogenerated from (1S, 2S)-2-amino-1-(4-nitrophenyl)-propane-1,3-diol derivatives (derivatives of p-nitrophenylserinol) in a “redox” flow cell equipped with two consecutive porous electrodes of opposite polarities. In spite. of the relative instability in methanol-acetate buffer of the hydroxylamine intermediates produced at the first porous electrode (cathode), the nitroso derivatives were prepared in good yields at the second one (anode). A coupling reaction between some nitroso derivatives and p-toluenesulphinic acid led to N-sulphonylphenylhydroxylamines.