(2S,4S,5R,6R)-4-Acetoxy-6-((1R,2R)-1-acetoxy-2,3-dihydroxy-propyl)-2-p-tolylsulfanyl-5-(2,2,2-trifluoro-acetylamino)-tetrahydro-pyran-2-carboxylic acid methyl ester   、                                                                                      
氯乙酰氯                                                                                                                                                              在
                                                                                                                                                                                 
吡啶                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                    反应 3.0h,
                                                                                                                以90%的产率得到methyl 4,7-di-O-acetyl-8,9-di-O-chloroacetyl-3,5-dideoxy-2-(4-methylphenylthio)-5-trifluoroacetamido-D-glycero-α-D-galacto-2-nonulopyranosidonate