Patent ID: 7915224

Claim:
In a method for producing a LHRH antagonist, which comprises converting a tripeptide represented by the formula [I]: Ac-D-2Nal-D-4ClPhe-D-3Pal-OH [I] or a salt thereof to said LHRH antagonist, the improvement being said tripeptide represented by the formula [I] or a salt thereof is prepared by the method comprising: hydrolyzing a compound represented by the formula [VII] or a salt thereof in the presence of a solvent to yield the tripeptide represented by the formula [I] or a salt thereof, wherein, said compound represented by the formula [VII] is: Ac-D-2Nal-D-4ClPhe-D-3Pal-OR 2 [VII] wherein R 2 represents methyl, ethyl or benzyl.