| 摘要 |
The invention provides a process for preparing piperazic acid derivatives of the general formula (I), wherein R<1> is C1-20-alkyl and R<2> is hydrogen, C1-6-alkyl, C1-6-haloalkyl, C1-6-alkoxy, allyloxy, 2,2,2-trichloroethoxy, 2-iodoethoxy, optionally substituted phenyl, benzyloxy, 4-methoxybenzyloxy or 2,4-dimethoxybenzyloxy, which process comprises reacting a 2,5-dihalopentanoate of the general formula (II): CH2X-CH2-CH2-CH2X-COOR<1> (II), wherein X is Br or Cl and R<1> is as defined above, in the presence of a base with a hydrazine derivative of the general formula (III): R<2>CONH-NHCOR<2>, wherein R<2> is as defined above. It further provides a process for preparing alkali salts of piperazic acid and derivatives of piperazic acid of the general formula (VI), wherein R<3> is C1-6-alkyl, allyl, 2,2,2-trichloroethyl, 2-iodoethyl, benzyl, 4-methoxybenzyl or 2,4-dimethoxybenzyl. |
