Synthesen von α‐Aminophosphonsäuren aus N‐Ethoxyiminium‐Salzen, II

Syntheses of α‐Aminophosphonic Acids from N‐Ethoxyiminium Salts, II Nitrones 2 obtained from aldehydes 1 are used for the synthesis of N‐ethoxyiminium salts 3. These react with several esters of hydrogen phosphite 4 to give the N‐methyl α‐amino phosphonic esters 5 to 13. The N‐benzyl α‐amino phosphonic esters 24 and 25 can be obtained by the same procedure. Hydrogenolysis and ester hydrolysis afford the α‐amino phosphonic acids 14 as well as 26 and 27, respectively.