Indole Derivatives

1 . A compound of formula (I), or a pharmaceutically acceptable salt thereof:

wherein R 1 is halogen, or alkyl,

R 2 is hydrogen, or halogen, and

Ar is one of the following groups:

in which R 3 and R 4 are independently hydrogen, halogen, alkyl, cycloalkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, hydroxy, phenyl, halophenyl, cyanophenyl, pyridyl, halopyridyl, thienyl or halothienyl, or R 3 and R 4 together with carbon atoms to which they are attached form a fused benzene, furan or dihydrofuran ring.

2 . The compound according to claim 1 , wherein R 1 is halogen,

R 2 is hydrogen, and R 3 and R 4 are independently hydrogen, halogen, alkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, phenyl, halophenyl, cyanophenyl, pyridyl or halopyridyl, or R 3 and R 4 together with carbon atoms to which they are attached form a fused benzene, furan or dihydrofuran ring.

3 . The compound according to claim 2 , wherein R 3 and R 4 are independently hydrogen, halogen, alkyl, haloalkyl, alkoxy, haloalkoxy, or R 3 and R 4 together with carbon atoms to which they are attached form a fused furan or dihydrofuran ring.

4 . The compound according to claim 2 , wherein Ar is

5 . The compound according to claim 4 , wherein R 3 is halogen, alkyl, haloalkyl, alkoxy, or haloalkoxy.

6 . The compound according to claim 5 , wherein R 1 is chlorine.

7 . The compound according to claim 6 , wherein R 3 is halogen, haloalkyl or haloalkoxy.

8 . The compound according to claim 4 , wherein R 1 is fluorine and R 3 is alkyl, alkoxy, haloalkyl or haloalkoxy.

9 . The compound according to claim 2 , wherein Ar is

10 . The compound according to claim 9 , wherein R 1 is halogen, and R 3 is halogen or alkyl.

11 . The compound according to claim 2 , wherein Ar is

in which represents a single bond or a double bond.

12 . The compound according to claim 1 , wherein the compound is selected from a group consisting of:

4-chloro-3-(4-ethylphenylmethyl)-1-(β-D-glucopyranosyl)indole;

4-chloro-3-(4-ethoxyphenylmethyl)-1-(β-D-glucopyranosyl)indole;

3-(5-bromothiophen-2-yl-methyl)-4-chloro-1-(β-D-glucopyranosyl)indole;

3-(4-ethylphenylmethyl)-4-fluoro-1-(β-D-glucopyranosyl)indole; and

a pharmaceutically acceptable salt thereof.

13 . The compound according to claim 1 , wherein the compound is selected from a group consisting of:

4-chloro-3-(4-chlorophenylmethyl)-1-(β-D-glucopyranosyl)indole;

3-(4-ethoxyphenylmethyl)-4-fluoro-1-(β-D-glucopyranosyl)indole;

3-(4-bromophenylmethyl)-4-chloro-1-(β-D-glucopyranosyl)indole;

3-(benzo[b]furan-5-yl-methyl)-4-chloro-1-(β-D-glucopyranosyl)indole;

4-chloro-3-(4-(difluoromethyl)phenylmethyl)-1-(β-D-glucopyranosyl)indole;

4-chloro-3-(4-(difluoromethoxy)phenylmethyl)-1-(β-D-glucopyranosyl)indole;

4-chloro-3-(4-iodophenylmethyl)-1-(β-D-glucopyranosyl)indole;

4-chloro-3-(4-(trifluoromethoxy)phenylmethyl)-1-(β-D-glucopyranosyl)indole; and

a pharmaceutically acceptable salt thereof.

14 . A pharmaceutical composition comprising the compound as set forth in claim 1 and a pharmaceutically acceptable carrier or diluent.

15 . The pharmaceutical composition according to claim 14 , which further comprises another antidiabetic agent.

16 . A compound as set forth in claim 1 for use as an active therapeutic substance.

17 . Use of a compound as set forth in claim 1 in the manufacture of a medicament for use in the treatment of disorders selected from diabetes mellitus, diabetic retinopathy, diabetic neuropathy, diabetic nephropathy, delayed wound healing, insulin resistance, hyperglycemia, hyperinsulinemia, elevated blood levels of fatty acids, elevated blood levels of glycerol, hyperlipidemia, obesity, hypertriglyceridemia, Syndrome X, diabetic complications, atherosclerosis, and hypertension.

18 . A method for treatment or delaying the progression or onset of diabetes mellitus, diabetic retinopathy, diabetic neuropathy, diabetic nephropathy, delayed wound healing, insulin resistance, hyperglycemia, hyperinsulinemia, elevated blood levels of fatty acids, elevated blood levels of glycerol, hyperlipidemia, obesity, hypertriglyceridemia, Syndrome X, diabetic complications, atherosclerosis, or hypertension, which comprises administering to a mammalian species in need of treatment a therapeutically effective amount of the compound as set forth in claim 1 .

19 . A method for treatment of type 1 or type 2 diabetes mellitus, which comprises administering to a mammalian species in need of treatment a therapeutically effective amount of the compound as set forth in claim 1 alone, or in combination with another antidiabetic agent, an agent for treating diabetic complications, an anti-obesity agent, an antihypertensive agent, an antiplatelet agent, an anti-atherosclerotic agent and/or a hypolipidemic agent.

20 . A process for preparing a compound of formula:

wherein the symbols are the same as defined in claim 1 , or a pharmaceutically acceptable salt thereof, which comprises deprotecting a compound of formula (II)

wherein R 5 is a protecting group for hydroxyl group and the other symbols are the same as defined above, followed by converting the resulting compound into a pharmaceutically acceptable salt thereof, if desired.

21 . A compound of formula (II)

wherein R 5 is a protecting group for a hydroxy group and the other symbols are the same as defined in claim 1 , or a salt thereof.