Prostacyclin derivatives and analogs are useful pharmaceutical compounds possessing activities such as platelet aggregation inhibition, gastric secretion reduction, lesion inhibition, vasodilation, and bronchodilation.
Treprostinil is a synthetic prostacyclin derivative currently marketed as an active pharmaceutical ingredient (API) for its ability to inhibit pulmonary arterial hypertension under the trade name Remodulin®. Treprostinil was first described in U.S. Pat. No. 4,306,075.
Prostacyclin derivatives are traditionally synthesized using a variety of methods that are described in J. Org. Chem. 2004, 69, 1890-1902, Drug of the Future, 2001, 26(4), 364-374, U.S. Pat. Nos. 4,306,075; 6,441,245; 6,528,688; 6,700,025; 6,765,117; 6,809,223 and U.S. patent application publication nos. 2009/0163738, 2011/0319641 A1, as well as Canadian patent application publication no. 2710726 A1. The entire teachings of these documents are incorporated herein by reference in their entireties. Also disclosed in these publications are processes and intermediates useful for the preparation of Treprostinil. However, the methods of these teachings suffer from one or more problems including toxic oxidation reagents, reduced yields, elevated levels of impurities, poor scalability, and numerous chromatography steps to purify intermediates and final products. Thus, there remains a need for safe, scalable, efficient, and economical processes for the preparation of Treprostinil.