Prior art

US Patent 12527771, titled "Viral inhibitors, the synthesis thereof, and intermediates thereto," references several U.S. patents as prior art. These references provide context for the invention, particularly concerning the synthesis and polymorphic forms of maribavir.

The identified prior art references and their potential anticipatory scope are detailed below. It is important to note that without the specific claims of US12527771, the assessment of anticipation under 35 U.S.C. § 102 is based on the general description of the invention in US12527771 and the summary provided for the cited prior art.

Most Relevant Prior Art for US12527771

1. U.S. Pat. No. 6,617,315

   • Full Citation: US 6,617,315 B1, "Ribofuranosylbenzimidazoles"
   • Publication/Filing Date: Granted September 9, 2003 (Application filed: December 14, 2001).
   • Brief Description: This patent discloses an alternative synthetic route for 2-(alkylamino)-1H-benzimidazoles, including steps for using 1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluenesulfonate as a desulfurizing agent, coupling 2-(alkylamino)-1H-benzimidazoles with 1,2,3,5-tri-O-acetyl-ribofuranose, and subsequent deprotection. It specifically details the synthesis of the acetyl-protected intermediate of maribavir in Scheme 3, Examples 24 and 25. The present patent (US12527771) explicitly states that the '315 patent does not exemplify the deacetylation of 5,6-dichloro-2-(isopropylamino)-1-(2,3,5-tri-O-acetyl-betal-L-ribofuranosyl)-1H-benzimidazole to afford maribavir.
   • Potential Anticipation: This patent potentially anticipates claims in US12527771 related to earlier steps in the synthesis of maribavir, particularly the formation of the benzimidazole core and its coupling with protected ribofuranose, as well as the acetyl-protected intermediate compound. Any claims in US12527771 covering these specific intermediate compounds or the methods of their preparation, as disclosed in US 6,617,315, could be anticipated. However, it does not anticipate the final deacetylation step to yield maribavir itself.

2. U.S. Pat. No. 6,482,939

   • Full Citation: US 6,482,939 B1, "Crystal forms of a benzimidazole riboside"
   • Publication/Filing Date: Granted November 19, 2002 (Application filed: November 15, 2001).
   • Brief Description: This patent discloses a particular polymorphic form of maribavir, specifically Form VI. US12527771 refers to this patent when discussing methods of preparing maribavir in Form VI, free of other crystal forms, solvates, or hydrates, and also for solid oral formulations comprising maribavir polymorphic Form VI with particular particle size distributions.
   • Potential Anticipation: This patent potentially anticipates claims in US12527771 directed to maribavir in its Form VI polymorphic form, pharmaceutical compositions comprising maribavir Form VI, and methods for preparing maribavir in Form VI, especially if such claims describe the physical form itself or compositions containing it without significant novel process steps or impurity profiles not found in the '939 patent. Claims related to specific particle size distributions of Form VI, if not specifically taught or rendered obvious by US 6,482,939, might not be anticipated.

3. U.S. Pat. No. 8,546,344

   • Full Citation: US 8,546,344 B2, "Processes for preparing crystalline maribavir"
   • Publication/Filing Date: Granted October 1, 2013 (Application filed: January 30, 2013).
   • Brief Description: This patent is cited in US12527771 as describing "other polymorphic forms" of maribavir, alongside US 6,482,939 and US 11,130,777, in the context of providing compositions comprising maribavir substantially free of these other polymorphic forms.
   • Potential Anticipation: This patent potentially anticipates claims in US12527771 that broadly cover other polymorphic forms of maribavir, their compositions, or general processes for their preparation. The significance for US12527771 lies in differentiating its "substantially free of other polymorphic forms" claims from what is taught in US 8,546,344.

4. U.S. Pat. No. 11,130,777

   • Full Citation: US 11,130,777 B2, "CRYSTALLINE MARIBAVIR FORM A"
   • Publication/Filing Date: Granted September 28, 2021 (Application filed: May 11, 2021).
   • Brief Description: Similar to US 8,546,344, this patent is cited in US12527771 as describing "other polymorphic forms" of maribavir, indicating it relates to different crystalline forms of the compound.
   • Potential Anticipation: This patent potentially anticipates claims in US12527771 that cover specific polymorphic forms of maribavir (e.g., Form A as indicated by the title of '777 patent), compositions containing them, or methods of their manufacture. US12527771 differentiates itself by aiming for compositions substantially free of the forms described in this patent.