Described herein are compounds of Formula I:




wherein R1-R6 are as described herein, for use in the treatment of a coronavirus infection; a method of inhibiting a coronavirus 3CL protease, by contacting the 3CL protease with a compound of Formula I; as well as methods pharmaceutical composition comprising a compound of Formula I and at least one phospholipid, wherein a weight ratio of the phospholipid(s) to the compound in the composition is in a range of from 10:1 to 1:10. Further described herein is a method of treating a coronavirus infection in a subject in need thereof, by administering to the subject at least one compound that exhibits at least two of: inhibition of an activity of a 3CL protease of the coronavirus; inhibition of inflammation in the subject; and inhibition of autophagy in the subject.