Synthesis of Cysteine and Homoglutathione Conjugates of Crop Protection Agents Containing Electrophilic Centers

摘要

It has been well documented that pesticides containing electrophilic centers can be metabolized in legumes via conjugation with the tripeptides glutathione and homo-glutathione (gamma-(R)-glu-(R)-cys-beta-ala). In some instances, cysteine conjugates also appear as a result of peptide cleavage. Soybean metabolism studies on the aulfon-amide herbicide DE-565 (1) have led to the isolation of several polar metabolites. In view of the many reports of homo glutathione conjugation in such species and as a part of our continued interest in the synthesis/identification of pesticide metabolites, we initiated studies directed at a practical synthesis of such conjugates. Reported herein is a general method for the preparation of homoglutathione and cysteine conjugates of electro-philes and specifically the synthesis of the homoglutathione and cysteine conjugates of DE-565 (1).