Synthesis and Development of a Nonaflate Ester in the Large-Scale Preparation of 3-Deoxymorphine

A series of novel activated esters of morphine were synthesized as alternatives to the triflate ester and submitted to hydrogenolysis conditions. Of these, only the novel nonaflate ester could be transformed with full conversion into the useful intermediate, 3-deoxymorphine, which was isolated in good yield and high purity without chromatography. This conversion proceeded significantly faster than for the triflate ester and with synthesis of the intermediate nonaflate at much reduced cost, an important factor for the large-scale preparation of 3-deoxymorphine in drug development projects.