ABT450

Paritaprevir hydrate, a second-generation NS3/4A protease inhibitor, is a component of the all-oral, interferon-free hepatitis C virus combination therapy developed by Enanta Pharmaceuticals and AbbVie. The fixed-dose tablet of paritaprevir, ombitasvir (XXV, NS4A replication complex inhibitor), and ritonavir (cytochrome P450 inhibitor) taken in combination with dasabuvir (X, NS5B polymerase inhibitor) was approved for the treatment of chronic HCV genotype 1 in the USA and EU in 2014, and further approved for treatment of genotype 4 chronic HCV infection without cirrhosis by the US FDA in 2015. After 12 weeks of combination treatment, high sustained virological response rates have been demonstrated in clinical trials.205 Paritaprevir joins other marketed NS3/4A inhibitors, including telaprevir, boceprevir, simeprevir, and vaniprevir (XXXVIII), which inhibit a critical enzymatic complex for HCV replication. It exhibits potent antiviral activity against HCV genotype 1a and 1b strains, with EC50 values of 1.0 and 0.21 nM respectively. As paritaprevir is metabolized by CYP3A4, ritonavir, a CYP3A inhibitor with no direct HCV antiviral properties, is dosed concurrently to boost paritaprevir exposure, raising the mean plasma half-life to ca. 5.5 h and allowing for once-daily dosing. While several development routes for paritaprevir have been published in the patent literature, no process route has been disclosed to date. Perceptibly the most scalable route is described below; no yields for this route have been reported. Notably, the synthesis of a closely related compound that shares the same macrocylic core has been reported by AbbVie on kilogram scale.