US 12527771

US patent 12527771, titled "Viral inhibitors, the synthesis thereof, and intermediates thereto," was assigned to Takeda Pharmaceutical Co Ltd. The inventors listed are Jeffrey Scott DEPUE, Suresh Kumar Tipparaju, Helge Alfred REISCH, Datong Tang, and Kishore Ramachandran. The patent has a filing date of July 7, 2025, and was issued on January 20, 2026.

Abstract:
The patent describes methods for preparing maribavir, or its pharmaceutically acceptable salts. These methods include novel synthesis and purification techniques for maribavir intermediates, as well as new methods for purifying maribavir itself. The disclosure also covers compositions of maribavir, or its pharmaceutically acceptable salts, which contain reduced or low levels of impurities, and methods for treating viral infections using maribavir.

Independent Claims Overview:

• Independent Claim 1: This claim outlines a method for preparing a compound of Formula 2 (an intermediate for maribavir). It involves combining a compound of Formula 5 and a compound of Formula 6 in a specific amount of solvent (between 1.0 L/kg and 10.0 L/kg of Compound 5). The mixture is then heated to a temperature (T7) between approximately 90° C. and 110° C. and maintained at this temperature for 12 to 20 hours. Formulas 5, 6, and 2 are defined with specific R1 (optionally substituted C1-6 aliphatic, carbocyclyl, heterocyclyl, phenyl, or heteroaryl) and R2 (halogen) groups.
• Independent Claim 8: This claim details a method for preparing a compound of Formula 3 (another maribavir intermediate). It involves combining the compound of Formula 2 (as defined in claim 1) and a compound of Formula 8 in a solvent amount between 1.0 L/kg and 10.0 L/kg of Compound 2. The reaction mixture is heated to a temperature (T1) between approximately 90° C. and 110° C. and held for 12 to 20 hours to yield the compound of Formula 3. R1 and R2 are defined as in Claim 1, PG1 is a suitable oxygen protecting group, and X represents a salt of compound 3a.
• Independent Claim 12: This claim describes a method for preparing maribavir itself, or a pharmaceutically acceptable salt thereof. It involves combining the compound of Formula 3 (as defined in Claim 8) and a compound of Formula 4 in a solvent amount between 5.0 L/kg and 10.0 L/kg of Compound 3. The mixture is heated to a temperature (T4) between approximately 50° C. and 70° C. and maintained for 1 to 5 hours to produce maribavir. R1 and R2 are defined as in Claim 1, and PG1 is a suitable oxygen protecting group.

CAFC 2026 Dockets:
As of April 26, 2026, no dockets specifically related to US12527771 have been found in the CAFC 2026 dockets. However, there are two related cases filed in the New Jersey District Court: 2:26-cv-04939 and 2:26-cv-04121. The patent also notes that the "First worldwide family litigation filed" is linked via Darts-ip.