(3S,6S)-6-cyclopentyl-3-isobutylpiperazin-2-one 、
5-(4-氟苯基)异噁唑-3-甲醛 、
(3S,6S)-3,6-diisobutyl-4-((5-phenylisoxazol-3-yl)methyl)piperazin-2-one 以to furnish 208 (55 mg, 61% yield) as white solid的产率得到(3S,6S)-6-cyclopentyl-4-((5-(4-fluorophenyl)isoxazol-3-yl)methyl)-3-isobutylpiperazin-2-one