(3S,6S)-3-isobutyl-6-thiophen-3-yl-piperazin-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 afford 442 (53 mg, 61% yield) as a colorless solid的产率得到(3S,6S)-4-((5-(4-fluorophenyl)isoxazol-3-yl)methyl)-3-isobutyl-6-(thiophen-3-yl)piperazin-2-one