Compounds for treatment of cardiac arrhythmia and methods of use

1. A substantially pure compound of structural formula II:

or a pharmaceutically acceptable salt thereof, wherein

R 1 is H or C 1 –C 10 alkyl;

R 2 is H or optionally substituted C 1 –C 10 alkyl, heteroalkyl, cycloalkyl, or heterocycloalkyl;

n=0 to 4;

p=0 or 1;

R 3 and R 4 are, independently, H or C 1 –C 4 alkyl.

2. The compound according to claim 1 wherein

R 1 is ethyl;

R 2 is (S)-2-butyl, (R)-2-butyl, (S)-3-methyl-2-butyl, or (R)-3-methyl-2-butyl;

n=0 or 1, most preferably n=1;

p=0; and, R 3 and R 4 are, independently, H or methyl.

3. The compound according to claim 2 wherein n is 1.

4. The compound according to claim 1 selected from:

5. The compound according to claim 1 selected from

a) (S)-{3-[4-(2-Ethylamino-ethoxy)-3,5-diiodo-benzoyl]-benzofuran-2-yl}-acetic acid sec-butyl ester;

b) {3-[4-(2-Ethylamino-ethoxy)-3,5-diiodo-benzoyl]-benzofuran-2-yl}-acetic acid;

c) (S)-{3-[4-(2-Amino-ethoxy)-3,5-diiodo-benzoyl]-benzofuran-2-yl}-acetic acid sec-butyl ester;

d) {3-[4-(2-Amino-ethoxy)-3,5-diiodo-benzoyl]-benzofuran-2-yl}-acetic acid;

e) (R)-{3-[4-(2-Ethylamino-ethoxy)-3,5-diiodo-benzoyl]-benzofuran-2-yl}-acetic acid sec-butyl ester;

f) (R)-{3-[4-(2-Amino-ethoxy)-3,5-diiodo-benzoyl]benzofuran-2-yl}-acetic acid sec-butyl ester;

g) (S)-{3-[4-(2-Ethylamino-ethoxy)-3,5-diiodo-benzoyl]benzofuran-2-yl}-acetic acid 1,2-dimethyl-propyl ester;

h) (R)-{3-[4-(2-Ethylamino-ethoxy)-3,5-diiodo-benzoyl]-benzofuran-2-yl}-acetic acid 1,2-dimethyl-propyl ester;

i) (S)-{3-[4-(2-Amino-ethoxy)-3,5-diiodo-benzoyl]benzofuran-2-yl}-acetic acid 1,2-dimethyl-propyl ester; and

j) (R)-{3-[4-(2-Amino-ethoxy)-3,5-diiodobenzoyl]benzofuran-2-yl}-acetic acid 1,2-dimethyl-propyl ester.

6. A composition comprising a compound according to claim 1 and a pharmaceutically acceptable carrier, diluent, or excipient.

7. A composition comprising a compound according to claim 2 and a pharmaceutically acceptable carrier, diluent, or excipient.

8. A composition comprising a compound according to claim 3 and a pharmaceutically acceptable carrier, diluent, or excipient.

9. A composition comprising a compound according to claim 4 and a pharmaceutically acceptable carrier, diluent, or excipient.

10. A composition comprising a compound according to claim 5 and a pharmaceutically acceptable carrier, diluent, or excipient.

11. A method of treating cardiac arrhythmias comprising administering to a patient experiencing a cardiac arrhythmia an effective amount of a composition according to claim 6 .

12. A method of treating cardiac arrhythmias comprising administering to a patient experiencing a cardiac arrhythmia an effective amount of a composition according to claim 7 .

13. A method of treating cardiac arrhythmias comprising administering to a patient experiencing a cardiac arrhythmia an effective amount of a composition according to claim 8 .

14. A method of treating cardiac arrhythmias comprising administering to a patient experiencing a cardiac arrhythmia an effective amount of a composition according to claim 9 .

15. A method of treating cardiac arrhythmias comprising administering to a patient experiencing a cardiac arrhythmia an effective amount of a composition according to claim 10 .