3-amino-O5,O6-isopropylidene-O8-trityl-D-allo-4,7-anhydro-2,3-dideoxy-oct-2-enonic acid ethyl ester   、                                                                                      
potassium thioacyanate   、                                                                                      
氯甲酸乙酯                                                                                                                                                                                                                                                                                                          生成                                                 6-(
O2,
O3-isopropylidene-
O5-trityl-α-
D-ribofuranosyl)-2-oxo-4-thioxo-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid ethyl ester   、                                                                                             
6-(O2,O3-isopropylidene-O5-trityl-β-D-ribofuranosyl)-2-oxo-4-thioxo-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid ethyl ester