CYP3A4-Mediated Bioactivation of the β-Amyloid Precursor Protein-Cleaving Enzyme 1 Inhibitor JNJ-54861911 Results in Redox-Neutral Addition of Glutathione via Catalysis by Glutathione S-Transferase α1, Identified as the Major Target Protein in Human Hepatocytes.

The β-amyloid precursor protein-cleaving enzyme 1 (BACE1) inhibitor JNJ-54861911, a candidate for the treatment of Alzheimer's disease, was withdrawn from clinical trials due to drug-induced liver injury (DILI). This paper describes our investigation of the metabolism of JNJ-54861911 to understand the potential contribution to the observed DILI. In human hepatocytes, JNJ-54861911 is metabolized by CYP450 3A4 to a reactive intermediate (RI), which undergoes glutathione (GSH) addition at C6 of the 2-amino-4-methyl-1,3-thiazin-4-yl moiety via glutathione S-transferase α1 (GSTA1) catalysis.

Ring-Closing Metathesis on Commercial Scale: Synthesis of HCV Protease Inhibitor Simeprevir.

The key macrocyclization step in the synthesis of simeprevir, a hepatitis C virus (HCV) antiviral drug, was studied. N-Boc substitution on the diene precursor changes the site of insertion of the metathesis catalyst and, consequently, the kinetic model of the ring closing metathesis (RCM), enabling a further increase in the macrocyclization efficiency under simulated high dilution (SHD) conditions. NMR of the inserted species of both first and second generation RCM catalysts are reported and discussed.

Origin of the E/Z Selectivity in the Synthesis of Tetrasubstituted Olefins by Wittig Reaction of α-Fluorophosphonium Ylides: An Explanation for the Low Stereoselectivity Observed in Reactions of α-Alkoxy Aldehydes.

A series of tetrasubstituted fluoroalkenes were synthesized in good yield and high E/Z selectivity (up to 96/4) by Wittig reaction between α-heterosubstituted ketones and α-fluorophosphonium ylides. A detailed study of factors that control stereoselectivity in these reactions shows that stereoselectivity is the result of stabilizing CH···F and N···C═O interactions in the addition TS leading to the E isomer. This analysis provides a rationale for the observed decrease in selectivity for reactions of stabilized ylides with α-alkoxy aldehydes.

Practical synthesis of (2'R)-2'-deoxy-2'-C-methyluridine by highly diastereoselective homogeneous hydrogenation.

Diastereoselective hydrogenation of 2'-deoxy-2'-exo-methyleneuridine was carried out under homogeneous conditions using a low loading of a chiral Rh catalyst. This, coupled with improvements in the synthesis of the substrate, allowed the smooth pilot plant preparation of the title compound on >10 kg scale.