2-Ethoxybenzoxazole as a bioisosteric replacement of an ethyl benzoate group in a human rhinovirus (HRV) capsid binder.

A series of pyridazinylpiperidinyl capsid-binding compounds with novel bicyclic substituents were synthesized and screened against human rhinovirus (HRV). Several 2-alkoxy- and 2-alkylthio-benzoxazole and benzothiazole derivatives showed excellent anti-HRV activity. When tested against a panel of 16 representative HRV types the 2-ethoxybenzoxazole derivative 13 was found to have superior HRV activity (median EC(50) 3.

An orally bioavailable oxime ether capsid binder with potent activity against human rhinovirus.

A series of capsid-binding compounds was screened against human rhinovirus (HRV) using a CPE based assay. The ethyl oxime ether 14 was found to have outstanding anti-HRV activity (median IC(50) 4.75 ng/mL), and unlike the equivalent ethyl ester compound 3 (Pirodavir), it has good oral bioavailability, making it a promising development candidate.