A compound of the general formula I: or an enantiomer, diastereomer, racemate, or pharmaceutically acceptable salt thereof, wherein R 1 each independently is selected from H, -OH, -COR 4, -COOR 4, -OCOOR 4, - OCON(R 4) 2, -(C 1 -C 16)alkylene-COOR 4, -CN, -NO 2, -SH, -SR 4, -(C 1 -C 16)alkyl, -O-(C 1 -C 16)alkyl, -N(R 4) 2, -CON(R 4) 2, -SO 2 R 4, -SO 2 NHR 4, -S(=O)R 4, or a nitric oxide donor group of the formula -X 1 -X 2 -X 3, wherein X 1 is absent or selected from -O-, -S- or -NH-; X 2 is absent or is (C 1 -C 20)alkylene optionally substituted by one or more -ONO 2 groups; and X 3 is -NO or -ONO 2, provided that at least one R 1 group is a nitric oxide donor group; R 2 each independently is selected from (C 1 -C 16)alkyl, (C 2 -C 16)alkenyl, or (C 2 -C 16)alkynyl; R 3 is selected from (C 1 -C 10)alkyl, (C 3 -C 10)cycloalkyl, (C 6 -C 14)aryl, or 4-12-membered heterocyclyl, each of which may optionally be substituted with -OH, -COR 5, -COOR 5, -(C 1 -C 8)alkylene-COOR 5, -CN, -NO 2, -(C 1 -C 8)alkyl, -O-(C 1 -C 8)alkyl, - N(R 5) 2, -CON(R 5) 2, -SO 2 R 5, -SO 2 NHR 5, or -S(=O)R 5; R 4 each independently is selected from H, (C 1 -C 8)alkyl, (C 3 -C 10)cycloalkyl, (C 6 -C 14)aryl, or 4-12-membered heterocyclyl, each of which other than H may optionally be substituted with -OH, -COR 5, -COOR 5, -OCOOR 5, -OCON(R 5) 2, -(C 1 -C 8)alkylene-COOR 5, -CN, -NO 2, -SH, -SR 5, -(C 1 -C 8)alkyl, -O-(C 1 -C 8)alkyl, -N(R 5) 2, -CON(R 5) 2, - SO 2 R 5, -SO 2 NHR 5, or -S(=O)R 5; R 5 each independently is selected from H, (C 1 -C 8)alkyl, (C 3 -C 10)cycloalkyl, (C 6 -C 14)aryl, or 4-12-membered heterocyclyl; and n is an integer of 1 to 3. or an enantiomer, diastereomer, racemate, or pharmaceutically acceptable salt thereof, wherein R 1 each independently is selected from H, -OH, -COR 4, -COOR 4, -OCOOR 4, - OCON(R 4) 2, -(C 1 -C 16)alkylene-COOR 4, -CN, -NO 2, -SH, -SR 4, -(C 1 -C 16)alkyl, -O-(C 1 -C 16)alkyl, -N(R 4) 2, -CON(R 4) 2, -SO 2 R 4, -SO 2 NHR 4, -S(=O)R 4, or a nitric oxide donor group of the formula -X 1 -X 2 -X 3, wherein X 1 is absent or selected from -O-, -S- or -NH-; X 2 is absent or is (C 1 -C 20)alkylene optionally substituted by one or more -ONO 2 groups; and X 3 is -NO or -ONO 2, provided that at least one R 1 group is a nitric oxide donor group; R 2 each independently is selected from (C 1 -C 16)alkyl, (C 2 -C 16)alkenyl, or (C 2 -C 16)alkynyl; R 3 is selected from (C 1 -C 10)alkyl, (C 3 -C 10)cycloalkyl, (C 6 -C 14)aryl, or 4-12-membered heterocyclyl, each of which may optionally be substituted with -OH, -COR 5, -COOR 5, -(C 1 -C 8)alkylene-COOR 5, -CN, -NO 2, -(C 1 -C 8)alkyl, -O-(C 1 -C 8)alkyl, - N(R 5) 2, -CON(R 5) 2, -SO 2 R 5, -SO 2 NHR 5, or -S(=O)R 5; R 4 each independently is selected from H, (C 1 -C 8)alkyl, (C 3 -C 10)cycloalkyl, (C 6 -C 14)aryl, or 4-12-membered heterocyclyl, each of which other than H may optionally be substituted with -OH, -COR 5, -COOR 5, -OCOOR 5, -OCON(R 5) 2, -(C 1 -C 8)alkylene-COOR 5, -CN, -NO 2, -SH, -SR 5, -(C 1 -C 8)alkyl, -O-(C 1 -C 8)alkyl, -N(R 5) 2, -CON(R 5) 2, - SO 2 R 5, -SO 2 NHR 5, or -S(=O)R 5; R 5 each independently is selected from H, (C 1 -C 8)alkyl, (C 3 -C 10)cycloalkyl, (C 6 -C 14)aryl, or 4-12-membered heterocyclyl; and n is an integer of 1 to 3.