| abstract |
A process for producing α or α,α'-substituted derivatives of bis(aminomethyl) phosphinic acid of formula (I) and their acid or basic salts, where R?1, R2 and R3¿ are as defined in the description, in which a bis(aminomethyl) phosphinic acid ester is converted into the corresponding bisimine which, after reaction with a base, is alkylated by R?2 and R3¿ in the α or α,α' position and, after subsequent acid treatment, is converted into a compound of formula (I). |