Chloromethyl chlorosulfate

N1-isomer 21 and the N6-regioisomer 20, resulting in modest isolated yields of intermediate 21. The preparation of chlorophosphate 19 was also challenging, with poor yields observed in both steps. ° Additionally, the commercial availability of chloromethyl chlorosulfate (CMCS) was limited at the time these processes were being conducted, and this issue needed to be addressed for the IcMig-term viabiUty of this approach. The final solvolysis proved to be chemically facile, consistently generating BMS-663068 in excellent yield and purity. 

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