Viral inhibitors, the synthesis thereof, and intermediates thereto

A composition of maribavir or a pharmaceutically acceptable salt thereof, and one or more compounds selected from the group consisting of Compound 13 or a salt thereof, Compound 14 or a salt thereof, and Compound 15 or a salt thereof, the composition comprising maribavir or a pharmaceutically acceptable salt thereof and one or more compounds selected from the group consisting of Compound 13 or a salt thereof, Compound 14 or a salt thereof, and Compound 15 or a salt thereof;

• wherein maribavir has the following structure:
• maribavir
• wherein Compound 13, Compound 14, and Compound 15 have the following structures:
• and wherein Compound 13 or a salt thereof is present in an amount of 0.1% w/w or less relative to maribavir, Compound 14 or a salt thereof is present in an amount of 0.1% w/w or less relative to maribavir, and Compound 15 or a salt thereof is present in an amount of 0.1% w/w or less relative to maribavir.