N-叔丁氧羰基-L-亮氨醇   、                                                                                      
N-(8-chloro-5-methyl-5H-chromeno[3,4-c]pyridin-2-yl)acetamide                                                                                                                                                                                                                                                                                                          以to afford tert-butyl((2S)-1-((2-acetamido-5-methyl-5H-chromeno[3,4-c]pyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate (290 mg, 0.617 mmol, 33% yield) as a yellow oil的产率得到tert-butyl ((2S)-1-((2-acetamido-5-methyl-5H-chromeno[3,4-c]pyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate