8-cyclopentyl-2-methanesulfinyl-6-thiazol-2-ylmethyl-8H-pyrido[2,3-d]pyrimidin-7-one   、                                                                                      
1-Boc-4-(4-氨基苯基)哌嗪                                                                                                                                                                                              以
                                                                                         
二甲基亚砜                                                                                  为溶剂,
                                                                                                                                                                                        以to give 4-[4-(8-cyclopentyl-7-oxo-6-thiazol-2-ylmethyl-7,8-dihydro-pyrido[2,3-d]pyrimidin-2-ylamino)-phenyl]-piperazine-1-carboxylic acid tert-butyl ester as a yellow foam (303 mg, 0.516 mmol, 64%)的产率得到4-[4-(8-cyclopentyl-7-oxo-6-thiazol-2-ylmethyl-7,8-dihydro-pyrido[2,3-d]pyrimidin-2-ylamino)-phenyl]-piperazine-1-carboxylic acid tert-butyl ester