Macrocyclic indoles as hepatitis C virus inhibitors

1. A compound having the formula (I) or an N-oxide, stereoisomer, tautomer, racemate or salt, thereof, wherein

R 1 is a bivalent chain which is

wherein the carbon atom carrying the R 5a and R 5b substituents is attached to the remainder of the molecule via the nitrogen atom of the amide group, and the carbon atom of the acetamide moiety is attached to the remainder of the molecule via the nitrogen of the indole ring of the compound of formula (I);

each of a, and b, is, independently, an integer selected from 0, 1, 2, 3, 4, or 5, with the proviso that the macrocycle formed by the bivalent chain R 1 , the —C(═O)—NH— moiety to which R 1 is attached and the nitrogen and carbon atoms N1, C6, C7, and C7′ of the indole ring, has from 14 to 17 member atoms;

each parallel dashed line (represented by ) represents an optional double bond;

R 2 is hydrogen or C 1-6 alkyl;

R 3 is C 3-7 cycloalkyl;

R 4 is

R 5a and R 5b are each independently selected from hydrogen; C 1-6 alkyl; or haloC 1-6 alkyl;

n is 0, 1, or 2;

R 6 is selected from hydrogen, halo, C 1-6 alkyl, or C 3-7 cycloalkyl;

R 8 is hydrogen, phenyl, or thiazolyl, wherein each phenyl is optionally substituted with one, two, or three substituents, wherein each thiazolyl is optionally substituted with one or two substituents; wherein the substituents on both phenyl and thiazolyl are each independently selected from halo; cyano; nitro; C 1-6 alkyl; —OR 12 ; —C(═O)OR 12 ; —C(═O)R 13 ; —C(═O)NR 9a R 9b ; —NR 9a R 9b ; —NR 9a C(═O)R 13 ; —NR 9a C(═O)—CH 2 —NR 9a R 9b ; —SR 10 ; —SO 2 R 11 ; —SO 2 NR 9a R 9b ; phenyl optionally substituted with one, two or three substituents each independently selected from halo, trifluoromethyl, cyano, C 1-6 alkyl, C 1-6 alkoxy, and —C(═O)NR 9a R 9b ; and Het optionally substituted with one or two substituents each independently selected from oxo, C 1-6 alkylsulfonyl, and C 1-6 alkyl;

R 9a and R 9b are each independently selected from hydrogen, C 1-6 alkyl, or arylC 1-6 alkyl; or R 9a and R 9b , together with the nitrogen to which they are attached, form a saturated, partially unsaturated, or completely unsaturated 5-8 membered monocycle, wherein said monocycle optionally contains one additional heteroatom selected from the group consisting of oxygen, sulfur and nitrogen, and wherein the remaining monocycle members are carbon atoms;

wherein said monocycle is optionally substituted on any carbon atom with one or two substituents each independently selected from halo, C 1-6 alkyl, hydroxy, or oxo, wherein aryl is phenyl or naphthyl;

R 10 is C 1-6 alkyl or C 3-7 cycloalkyl;

R 11 is C 1-6 alkyl or C 3-7 cycloalkyl;

R 12 is hydrogen, C 1-6 alkyl, or benzyl;

R 13 is C 1-6 alkyl;

Het is pyrrolidinyl, piperidinyl, morpholinyl, or piperazinyl.

2. A compound according to claim 1 , having the structural formula

wherein the parallel dashed line, a, b, R 3 , R 6 , n, and R 8 , have the same meaning as that defined in claim 1 .

3. A compound according to claim 1 , wherein each of a, and b, is, independently, 0, 1, 2, or 3, with the proviso that the macrocycle formed by the bivalent chain R 1 , the —C(═O)—NH— moiety to which R 1 is attached and the nitrogen and carbon atoms N1, C6, C7, and C7′ of the indole ring, has from 14 to 16 member atoms.

4. A compound according to claim 1 , wherein R 2 is hydrogen or C 1-4 alkyl.

5. A pharmaceutical composition comprising an anti-virally effective amount of a compound as claimed in claim 1 and a pharmaceutically acceptable carrier.

6. The compound of claim 1 which is 17-cyclohexyl-18-[4-[2-(4-methanesulfonylpiperazin-1-yl)-5-aminobenzyloxy]phenyl]-1,4,11-triazatricyclo[11.5.2.0 16,19 ]icosa-7,13(20),14,16(19),17-pentaene-3,12-dione.

7. The compound of claim 6 having the formula