(1aR,5S,8S,10R,22aR)-5-(1,1-Dimethylethyl)-1,1a,3,4,5,6,9,10,18,19,20,21,22,22a-tetradecahydro-14-methoxy-3,6-dioxo-8H-7,10-Methanocyclopropa[18,19][1,10,3,6]dioxadiazacyclononadecino[11,12-b]quinoxaline-8-carboxylic Acid Methyl Ester is an antiviral agent and Grazoprevir (M424985) intermediate. Grazoprevir is a second-generation NS3/4A protease inhibitor.