NEW MATERIAL: A compound of formula I [R is H, a C1-4 alkyl or CF3; R1 and R2 are each H, a C1-4 alkyl, CF3, phenyl or the like; A is a (substituted) methylene, (substituted) trimethylene, or the like; B is formula II (Z is H, a C1-4 alkyl, trialkylamino, phenyl or the like)], formula III [M is formula N-O-R3 (R3 is H, a C1-4 alkyl, alkylphenyl or the like), or the like].

EXAMPLE: 4-(2-oxo-3-phosphonopropyl)-2-piperazine carboxylic acid.

USE: Medical treatment agents for epilepsy, apoplexy, cardiac arrest, anxiety, pain or the like.

PROCESS: A piperazine derivative of formula IV (Y is a C1-4 alkyl), for example, is reacted with haloenol phosphonate derivative of formula V (E is a C1-4 alkyl or CF3), and then is deprotected and hydrolized optionally, to obtain the compound of formula I or formula III.