Abstract: [Problem] The present invention has as an object to provide an antiviral agent effective as a remedy for COVID-1 9 and other viral infections. [Resolution Means] Provided is an antiviral agent and the like, made of: the compound represented by general formula (1) or (2) below [R1 being —(CH2)n1—Z1—R11 2 r —CH—(—Z1—R11,)(n1 being 0 or 1; Z1 being a single bond, —O—, —NH—, —S—, —SO—, —SO2—,SO—CO—, —CO—O—, or —CH?N—O—; R11 being a hydrogen atom, an alkyl group having 1 to 6 carbons, —NR12 R13, —N3,—NO2,—CN, —CH2—CO—O—R14, or a five- or six-membered heterocyclic group including a nitrogen atom; R12 and R13 each independently being a hydrogen atom or an alkyl group having 1 to 6 carbons; and R14 being a hydrogen atom or an alkyl group having 1 to 6 carbons], a derivative thereof, a salt of these compounds, or a solvate thereof.

Abstract: The present invention provides a compound exhibiting coronavirus 3 CL protease inhibitory activity or a pharmaceutically acceptable salt thereof, and a pharmaceutical composition comprising the same. Furthermore, the present invention provides a crystalline form useful as an active pharmaceutical ingredient, and a pharmaceutical composition comprising the same. A compound represented by Formula: or a pharmaceutically acceptable salt thereof.

Abstract: The present invention provides a compound exhibiting coronavirus 3CL protease inhibitory activity or a pharmaceutically acceptable salt thereof, and a pharmaceutical composition comprising the same. Furthermore, the present invention provides a crystalline form useful as an active pharmaceutical ingredient, and a pharmaceutical composition comprising the same. A compound represented by Formula: , or a pharmaceutically acceptable salt thereof.

Abstract: The present invention provides a compound exhibiting coronavirus 3CL protease inhibitory activity or a pharmaceutically acceptable salt thereof, and a pharmaceutical composition comprising the same. Furthermore, the present invention provides a crystalline form useful as an active pharmaceutical ingredient, and a pharmaceutical composition comprising the same. A compound represented by Formula (I): wherein Y is N or the like; R1 is substituted or unsubstituted aromatic heterocyclyl or the like; R2 is substituted or unsubstituted aromatic carbocyclyl or the like; R3 is substituted or unsubstituted aromatic heterocyclyl or the like; —X— is —NH— or the like; m is 1 or the like; R5a is each independently a hydrogen atom or the like; R5b is each independently a hydrogen atom or the like; n is 1 or the like; R4a is each independently a hydrogen atom or the like; and R4b is each independently a hydrogen atom or the like, or a pharmaceutically acceptable salt thereof.