6-methylnicotinamide derivatives as antiviral agents

6-methylnicotinamide derivatives of formula 1 or their pharmaceutically acceptable salts:

• wherein,
• R1 is hydroxy group;
• straight or branched C1˜C5 alkyl group;
• C3˜C6 cycloalkyl group which is unsubstituted or substituted with hydroxy group, C2˜C6 dialkylamino group;
• saturated or unsaturated 5 or 6 membered heterocyclic compounds containing 1 to 2 heteroatoms selected from N, O and S which may be unsubstituted or substituted with C1˜C3 alkyl group;
• or
• m is an integer of 0 or 1,
• R2 is H or C1˜C4 alkyl group;
• or R1 and R2 are joined to form a 5- and 6-membered heterocyclic ring containing 1 to 2 heteroatoms selected from N, O and S,
• n is an integer from 0 to 4,
• R3 is 5-indazole or 6-indazole.