
%0 Journal Article
%A Chiefari, J 
%A Galanopoulos, S 
%A Janowski, WK 
%A Kerr, DIB 
%A Prager, RH 
%T The Synthesis of Phosphonobaclofen, an Antagonist of Baclofen
%J Australian Journal of Chemistry
%D 1987/09/01
%V 40
%N 9
%P 1511-1518
%K 
%R https://doi.org/10.1071/CH9871511
%U https://www.publish.csiro.au/paper/CH9871511 
%X Phosphonobaclofen, 3-amino-2-(4-chlorophenyl) propylphosphonic acid, has been synthesized in five steps from ethyl 3-(4-chloropheny1)but-2-enoate, and is a specific antagonist of baclofen . Two alternative synthetic pathways, involving conjugate addition of phosphite to 2-(4-chlorophenyl) propenenitrile and of cyanide to 2-(4-chlorophenyl) ethenylphosphonate ester, failed. Cyanide ion did add efficiently to ethyl 3-(4-chloropheny1)-2-diethoxyphosphinylprop-2- enoate, and hydrogenation followed by hydrolysis of the product gave (2S,3S)- and (2R,3R)-4-amino-3-(4-chloropheny1)-2-phosphonobutanoic acid, which is also undergoing pharmacological evaluation. 
