“…Ko143 was synthesized according to the procedure developed by Nakagawa et al (9,10). L-Tryptophan was converted into cis-1-isobutyl-7-methoxy-3-methoxycarbonyl-1, 2,3,4-tetrahydro-b-carboline, known as compound A, which was then condensed with Z-Glu(OBu t )-OH (11) in the presence of dicyclohexylcarbodiimide to form the corresponding amide.…”