Synthesis and anti-norovirus activity of pyranobenzopyrone compounds

During the last decade, noroviruses have gained media attention as the cause of large scale outbreaks of gastroenteritis on cruise ships, dormitories, nursing homes, etc. Although noroviruses do not multiply in food or water, they can cause large outbreaks because approximately 10-100 virions are sufficient to cause illness in a healthy adult. Recently, it was shown that the activity of acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1) enzyme may be important in norovirus infection. In search of anti-noroviral agents based on the inhibition of ACAT1, we synthesized and evaluated the inhibitory activities of a class of pyranobenzopyrone molecules containing amino, pyridine, substituted quinolines, or 7,8-benzoquinoline nucleus. Three of the sixteen evaluated compounds possess ED(50) values in the low micrometer range. 2-Quinolylmethyl derivative 3A and 4-quinolylmethyl derivative 4A showed ED(50) values of 3.4 and 2.4 μM and TD(50) values of >200 and 96.4 μM, respectively. The identified active compounds are suitable for further modification for the development of anti-norovirus agents.