Synthesis Optimization Of Obeticholic Acid And The Detection Of Residual Palladium

CDCA is the most potential endogenous bile acid with an EC₅₀ of 9.9?M.Obeticholic acid was found to be the most potential steroidal agonists with an EC₅₀ of 99 nM.Obeticholic acid as a new generation synthetic bile acid activator of FXR,was firstly reported by the researchers in University of Perugia,and the compound patent was authorized to Intercept Pharmaceuticals,Inc.The clinical research of this drug for the treatment of PBC has been successfully accomplished,and it was approved by the US Food and Drug Administration?FDA?in May 27,2016.The drug was also approved by the European Medicines Agency?EMA?in December 12,2017,with the trade name of Ocaliva.Several key steps of obeticholic acid synthetic route were optimized:?1?The enolization reaction conditions of C₇ carbonyl were systematically studied,and two methods to synthesize the key intermediate IV were successfully obtained.Compared with the reported methods,our method has several advantages such as mild reaction conditions,high product yield,easy operation and high potential of industrial transformation.?2?Two aldol condensation reagents:boron trifluoride acetonitrile and boron trifluoride etherate,were compared,and boron trifluoride acetonitrile was found to give good catalytic performance.?3?Other conditions,such as reaction temperature,reaction time,loading sequence of materials,ratio of materials and quenching temperature of reaction were systematically studied in the process of synthesizing key intermediate V,and the optimal reaction conditions were obtained.?4?The configuration transformation condition of 6?-ethyl of 3?-hydroxy-6?-ethyl-7-keto-5-cholan-24-oic acid was studied,and the optimal operation conditions were confirmed.Our synthesis route gave a better overall yield of 52.8%with a purity of 99.2%,The structure of the final product was characterized by ¹H-NMR?¹³C-NMR and HRMS spectra.Currently,countries around the world have strict rules of palladium residues in drugs.the European Medicines Agency?EMA?has made a clear regulation that the residues of palladium in medicine should be less than 1 ppm.It is inevitable to use palladium as hydrogenation catalyst in the synthesis process of obeticholic acid,which may cause excess metal palladium residues in products.So,in this part,a fluorescent probe was designed and synthesized to detect palladium ion residues in obeticholic acid.This probe exhibited excellent readout for Pd²⁺,and it was utilized to measured palladium ion in the real sample of obeticholic acid.Considering our Confidentiality Agreement with the cooperative company,only a part of the evaluation result of this probe for detecting Pd²⁺could be included in this part.And we found that this probe also exhibited good responds toward Ag⁺ion,thus,the detecting performance of this probe toward Ag⁺ion was studied.