e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Tetrahedron Letters
The preparation of N-substituted aminomethylidenebisphosphonates and their tetraalkyl esters via reaction of isonitriles with trialkyl phosphites and hydrogen chloride …
The reaction of isonitriles with trialkyl phosphites in the presence of hydrogen chloride gives tetraalkyl N-substituted aminomethylidenebisphosphonates via N-methylideneaminium (isonitrilium) salts. Hydrolysis or dealkylation of these tetraalkyl esters gives N-substituted aminomethylidenebisphosphonic acids in high yields.