| abstract |
(57) Abstract: A substituted phosphinic acid compound represented by the formula I or a salt or ester thereof: Wherein R 1 is a monovalent aromatic or aromatic ring-substituted aliphatic group attached to the indicated carbon atom via a carbon atom, R 2 is a substituted or unsubstituted hydrocarbyl group, R x is hydrogen or a substituted or unsubstituted hydrocarbyl group, R y is hydrogen, R y a or NH- protecting group, R y a is a substituted or unsubstituted hydrocarbyl group. |