A stable reagent for the preparation of N-o-nitrophenylthio-amino-acids

Abstract

N-o-Nitrophenylthio-amino-acids were prepared in high yield by treatment of amino-acids with o-nitrophenyl-sulphenyl thiocyanate, a very stable compound, in the presence of silver nitrate. This reagent reacted selectively with lysine to give N^α-mono-o-nitrophenylthio- and N^αN^ε-bis-o-nitrophenylthio-lysine with virtually none of the N^ε-monosubstituted isomer. o-Nitrophenylsulphenyl p-nitrophenolate was used for the preparation of N-o-nitrophenylthio-amino-acids and for the direct preparation of N-o-nitrophenylthio-L-phenylalanine p-nitrophenyl ester in moderate yield.