在
                                                                                                                                                                                 
哌啶                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
N,N-二甲基甲酰胺                                                                                  为溶剂,
                                                                                                                                                                                        生成                                                 (2S,4S)-4-({(2R,4S)-4-Amino-1-[2-(5-methyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-acetyl]-pyrrolidine-2-carbonyl}-amino)-1-[2-(5-methyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-acetyl]-pyrrolidine-2-carboxylic acid methyl ester