Description
N-SUBSTITUTED-SULFAMOYLBENZOIC ACID
DERIVATIVES, METHOD FOR PREPARING THEREOF AND
ANTIVIRAL PHARMACEUTICAL COMPOSITION
COMPRISING THE SAME Technical Field
[1] The present invention relates to Λf-substituted-sulfamoylbenzoic acid derivatives useful as an antiviral agent, and more particularly novel N - substituted-sulfamoylbenzoic acid derivatives having an excellent inhibitory effect on replication of Hepatitis C virus (HCV), represented by the following formula I:
[2]
...(D [3] or pharmaceutically acceptable salts thereof in which R i represents hydroxy group or -NR R group; R represents hydrogen atom, C -C straight or branched alkyl group,
2 3 2 1 4 or -(CH 2 ) m -R 4 group where R 4 represents phenyl group or heterocyclic ring, and m represents an integer between 0 and 4; and R represents C -C straight or branched
3 1 4 alkyl group, or -(CH ) -R group where R represents C -C dialkylamino group, het-
2 n 5 5 2 6 erocyclic ring, or heterocyclic ring substituted by C -C straight or branched alkyl
1 4 group, and n represents an integer between 0 and 4, to a method for preparing the compounds, and to an antiviral pharmaceutical composition comprising the same as an active ingredient.
Background Art
[4] Hepatitis C virus (HCV) is the major etiological agent of non-A and non-B viral hepatitis, mainly being post- transfusion and community-acquired. Once infected with HCV, approximately 80% of infected people, given its symptom is manifested, progress to chronic hepatitis, and the rest 20% of infected people progress to acute hepatitis causing hepatic cirrhosis, which is eventually transferred to liver cancer. According to a recently published report, more than 200 million worldwide are
infected with HCV. For instance, more than 4.5 million Americans are infected with the same virus (The number is likely to be 15 million in maximum.) and more than 5 million Europeans are HCV patients.
[5] HCV is a member of the Flaviviridae family. More specifically, HCV has about
9.5kb sized (+)- RNA (single stranded positive-sense RNA) genome inside its envelope. The RNA genome consists of an untranslational region at 5' and 3' ends (UTR) and a long open reading frame (ORF). This ORF is expressed as a polyprotein including 3,010 to 3,040 amino acids by host cell enzymes and divided into 3 structural proteins and 6 nonstructural proteins by host cell enzymes and its own protease. Also, there is a uniformly conserved region in the 5' and 3' end of the genome, respectively. This region is believed to play an important role for protein expression and RNA replication of the virus.
[6] The long ORF is expressed as a polyprotein, and through co-translational or post- translational processing, it is processed into structural proteins, i.e. core antigen protein (core) and surface antigen protein (El, E2), and nonstructural proteins, NS2 (protease), NS3 (serine protease, helicase), NS4A (serine protease cofactor), NS4B (protease cofactor, involved in resistance), NS5A, and NS5B (RNA dependent RNA polymerase, RdRp), each contributing to replication of virus. The structural proteins are divided into core, El, and E2 by signal peptidase of the host cell. Meanwhile, the nonstructural proteins are processed by serine protease (NS3) and cofactor (NS2, NS4A, and NS4B) of the virus. The core antigen protein together with surface antigen protein of the structural protein compose a capsid of the virus, and the nonstructural proteins like NS3 and NS5B play an important role of the RNA replication of the virus (Reference: Bartenschager, R., 1997, Molecular targets in inhibition of hepatitis C virus replication, Antivir. Chem. Chemother. 8: 281-301).
[7] Similar to other Flaviviruses, the 5' and 3' ends of the virus RNA has a uniformly conserved untranslational region (UTR). Generally, this region is known to play a very important role in replication of the virus. The 5' end has 5'-UTR composed of 341 nu¬ cleotides, and this part has the structure of 4 stem and loop (I, II, III, and IV). Actually, this functions as an internal ribosome entry site (IRES) necessary for translation processing to express protein. Particularly, the stem III, which has the biggest and the most stable structure with a conserved sequence, has been reported to play the most essential part for ribosome binding. In addition, a recent study tells that the virus proteins are expressed by initiation of translational processing from AUG that exists in the single RNA of the stem IV (Reference: Stanley, M. Lemon and Masao Honda, 1997, Internal ribosome entry sites within the RNA genomes of hepatitis C virus and other Flaviviruses, seminars in Virology 8:274-288).
[8] Moreover, the 3' end has 3'-UTR composed of 318 nucleotides. This part is known
to play a very important role in the initiation step of binding of NS5B, an essential enzyme of RNA replication. The 3'-UTR, according to the sequence and tertiary structure, is composed of three different parts: -X-tail-5' starting from the 5' end to 98th nucleotide (98nt.), -poly (U)- having UTP consecutively, and the rest of 3'-UTR-. More specifically, X-tail-5' part consists of 98 nucleotides having a very conserved sequence, and has three stem and loop structures, thereby forming a very stable tertiary structure. Probably, this is why X-tail-5' part is considered very essential of NS5B binding. Also, it is reported that -poly (U)- part induces a pyrimidine track, facilitating RNA polymerase effect. Lastly, the rest part of 3'-UTR has the tertiary structure of loop and plays an important role in NS5B binding. However, its structure is known somewhat unstable. Overall, the 3' end region of HCV RNA is known to have an essential structure in NS5B binding when the RNA replication starts (Reference: Yamada et al., 1996, Genetic organization and diversity of the hepatitis C virus genome, Virology 223:255-281).
[9] Among other enzymes of HCV, NS5B is the one that is directly involved in RNA replication and thus it is very important. NS5B is an enzyme consisting of 591 amino acids having the molecular weight of about 68kDa. There are two RNA-binding domains, i.e. RBDl and RBD2, in the NS5B enzyme. RBDl exists between the amino acid numbers 83 and 194, and RBD2 exists between the amino acid numbers 196 and 298. Meanwhile, essential motif amino acids for RNA binding and activity are 'Asp' (amino acid number 220), 'GIy' (amino acid number 283), 'GIy' (amino acid number 317), 'Asp' (amino acid number 318), 'Asp' (amino acid number 319), and 'Lys' (amino acid number 346). Further, provided that there exists a RNA template of the virus itself, this enzyme can lead a polymerization reaction without another primer (Reference: Lohmann, V. et al., 1997, Biochemical properties of hepatitis C virus NS5B RNA dependent RNA polymerase and identification of amino acid sequence motifs essential for enzymatic activity, /. viral. 71:8416-8428).
[10] RNA genome of HCV was isolated in 1989 by molecular cloning (Reference: Choo,
Q-L, et al., 1989, Isolation of a cDNA clone derived from a blood-borne non-A, non-B viral hepatitis genome. Science 244:359-362). Although there have been a number of molecular biological researches on HCV from that point, there were always limitations due to lack of more effective cell culture systems and animal models. Fortunately, the above problem has been somewhat resolved by the introduction of a hepatoma cell line which made it possible to replicate HCV more stably (Reference: Lohmann, V., F. Korner, J-O Koch, U. Herian, L. Theilmann, R. Bartenschlarger, 1999, Replication of subgenomic hepatitis c virus RNAs in a hepatoma cell line. Science 285: 110-113).
[11] So far, no one has actually found vaccine or therapeutics that is very effective for
HCV. Hence, many pharmaceutical companies and institutes around the world are now
trying to develop therapeutics and prevention of hepatitis C. HCV patients are prevalent in the world, and its frequency to be progressed to hepatic cirrhosis and/or liver cancer is much higher than HBV. Also, despite its high frequency to be progressed to chronic hepatitis, the research on infection mechanism of the virus is still under progress. People are infected with HCV through blood transfusion or medication via phleboclysis or tattooing, but most of cases HCV infection takes place through a direct blood contact. However, 40~50% of the HCV patients still do not exactly know how they became infected. In view of this situation, it is a very urgent matter to develop a new vaccine and therapeutics to treat the diseases. In general, HCV exist as diverse genotypes between strains and mutation. Once a person is progressed to chronic hepatitis from HCV, it is not hard to see reinfection or coinfection owing to genetic variants. Because of this, few succeeded to develop an effective vaccine for HCV. Another example of HCV treatments is using alpha interferon (α-interferon). However, this approach proved to be not that good because the effects of alpha interferon on different HCV genotypes were very diverse and when its administration was discontinued, patients relapsed into hepatitis C in most of cases. Hence it will be important to develop an inhibitor that binds only to a particular HCV protein in order to control HCV replication. The best targets of such research are NS3 protease/helicase and NS5B RNA polymerase of HCV. These enzymes are very useful for developing anti-HCV agent since these types of enzyme is not necessary for the host cell but essential for its own replication. In other words, NS5B of HCV (RNA dependent RNA polymerase} is an essential enzyme for HCV, and this makes the enzyme a good target for suppressing the replication of HCV.
[12] Now that HCV is not easily treated by vaccine, a new therapy using α-interferon and Ribavirin was introduced. But this, too, caused side effects and was not effective for treating hepatitis C. For example, about 25% of HCV patients showed no reaction to the interferon therapy, and about 25% reacted to it only for temporarily and relapsed into hepatitis C. The rest 50% of the patients maintained ALT at a normal level after the treatment was completed and their HCV RNA became negative. However, 50% of them relapsed into hepatitis C within 3~6 months. In short, only 25% of the HCV patients showed sustained response for more than 6 months. Meanwhile, the most HCV subtype found in patient world wide is 1 (Ia, Ib) that is not easily treated by interferon, compared to 2 and 3 subtypes. In case of combination therapy with interferon and ribavirin, the treatment effect was doubled. What is known about ribavirin is that when it was used alone, it showed little effect on HCV and rather, caused side effects like erythroclastic anemia. Thus ribavirin was prescribed only when the interferon therapy was no good or relapsed into Hepatitis C again. So far, no one actually developed an antiviral agent for treating hepatitis C by suppressing the
replication of HCV.
[13] The present invention, therefore, is directed to develop a nonnucleoside small molecule having low toxicity and side effect but manifesting excellent antiviral activity against HCV, by studying any possible compound that inhibits the activity of the re¬ combinant HCV RNA polymerase (NS5B, RNA polymerase).
[14] After making so much efforts for developing a compound with excellent antiviral activity against HCV as an attempt to develop a new HCV therapeutics having low toxicity and side effect, the inventors finally succeeded to synthesize novel N - substituted sulfamoylbenzoic acid derivatives represented by the above chemical formula I and proved that these compounds are indeed very effective for inhibiting the replication of HCV.
Disclosure of Invention Technical Problem
[15] It is, therefore, an object of the present invention to provide novel ^-substituted sul¬ famoylbenzoic acid derivatives and pharmaceutically acceptable salts thereof, and method for preparing the compounds.
[16] Another object of the present invention is to provide a pharmaceutical composition comprising the above compound as an effective component, which has little side effect and is economical, for prevention and treatment of hepatitis C. Technical Solution
[17] To achieve the above objects, the present invention provides novel ^-substituted sulfamoylbenzoic acidderivatives, represented by the following formula I:
[18]
...(I)
[19] or pharmaceutically acceptable salts thereof in which R represents hydroxy group or -NR R group; R represents hydrogen atom, C -C straight or branched alkyl group,
2 3 2 1 4 or -(CH 2 ) m -R 4 group where R 4 represents phenyl group or heterocyclic ring, and m represents an integer between 0 and 4; and R represents C -C straight or branched
3 1 4 alkyl group, or -(CH ) -R group where R represents C -C dialkylamino group, het-
2 n 5 5 2 6 erocyclic ring, or heterocyclic ring substituted by C -C straight or branched alkyl
group, and n represents an integer between 0 and 4.
[20] As aforementioned, the above compounds can be used in form of pharmaceutically acceptable salts. As for that salts, an acid addition salts that are prepared by pharma¬ ceutically acceptable free acids are available. The compounds with the chemical formula I can make pharmaceutically acceptable acid addition salts following the con¬ ventional method in the related art. As for free acids, both organic acids and inorganic acids can be used. For instance, inorganic acids include hydrochloric acid, hy- drobromic acid, sulfuric acid, and phosphoric acid. Organic acids include citric acid, acetic acid, lactic acid, tartaric acid, maleic acid, fumaric acid, formic acid, propionic acid, oxalic acid, trifluoroacetic acid, benzoic acid, gluconic acid, methanesulfonic acid, glycolic acid, succinic acid, 4-toluenesulfonic acid, benzenesulfonic acid, glutamic acid or aspartic acid.
[21] In another aspect, the present invention provides a method for preparing N - substituted-sulfamoylbenzoic acid derivatives of the formula I, represented by the following scheme I;
[22] [Scheme (I)]
[23]
( 1 , R1 = -NR2R3 )
[24] in which R represents hydrogen atom, C -C straight or branched alkyl group, or
1 4
(CH 2 ) m -R 4 group where R 4 represents phenyl group or heterocyclic ring, and m represents an integer between 0 and 4; and R represents C -C straight or branched
3 1 4 alkyl group, or -(CH ) -R group where R represents C -C dialkylamino group, het-
2 n 5 5 2 6 erocyclic ring, or heterocyclic ring substituted by C -C straight or branched alkyl group, and n represents an integer between 0 and 4. [25] As shown in the above scheme, the method for preparing N - substituted-sulfamoylbenzoic acid derivatives according to the present invention comprises the steps of: (i) reacting 4-(chlorosulfonyl)benzoic acid of Formula 2 with
4- (4-morpholino) aniline of Formula 3 to form 4-[/V-[4-(4-morpholino)phenyl] sulfamoyl] benzoic acid of Formula 4 (the desired compound of the present invention of formula I, in case R = hydroxy group); and (ii) after activating 4-[N - [4-(4-morpholino)phenyl]sulfamoyl]benzoic acid of Formula 4 prepared in the step (i) with general activating reagents such as pivaloyl chloride, thionyl chloride, or 3,5-dichloro-2-hydroxybenzenesulfonyl chloride, reacting with appropriate amine compounds represented by HNR R of Formula 5 to form N - substituted-sulfamoylbenzoic acid derivatives of Formula 6 (the desired compounds of the present invention of the formula I, in case R = -NR R ).
1 2 3
[26] 4-(chlorosulfonyl)benzoic acid, 4-(4-morpholino)aniline, and amine compounds represented by HNR R of Formula 5 used as starting materials and reactants in the scheme (I), and pivaloyl chloride, thionyl chloride, or
3,5-dichloro-2-hydroxybenzenesulfonyl chloride used as activating reagents in the step (ii) are commercially available.
[27] And appropriate amine compounds represented by HNR R of Formula 5 used in the step (ii) are appropriate reagents to introduce substituents to target compounds and can be suitably selected, depending on substituents to be introduced, by a person possessing ordinary knowledge in the art.
[28] To give more details on the step (i) of the preparation method described above, the reaction is performed in the presence of an organic base such as pyridine, N,N - dimethylaniline, Λ/,./V-diethylaniline, 2,6-lutidine, 2,4,6-collidine, 2,6-di-tert - butyl-4-methylpyridine and the like which is relatively weak base, in an organic solvent such as dichloromethane, chloroform, acetonitrile, Λ/,./V-dimethylformamide, Λ/,./V-dimethylacetamide, dimethylsulfoxide, l-methyl-2-pyrrolidinone, ethyl ether, isopropyl ether, tetrahydrofuran, acetone and the like, at a temperature in the range of 0 ~ 35°C within 5 hours.
[29] To give more details on the step (ii) of the preparation method described above, the reaction is performed in the presence of an organic base such as triethylamine, tribenzylamine, Λ/,./V-diisopropylethylamine, 4-methylmorpholine, 4-ethylmorpholine, 1-methylpiperidine, 1-ethylpiperidine, 1,1,3,3-tetramethylguanidine and the like which is relatively strong base, in an organic solvent such as dichloromethane, chloroform, acetonitrile, Λ/,./V-dimethylformamide, ΛζΛ^-dimethylacetamide, dimethylsulfoxide, l-methyl-2-pyrrolidinone, ethyl ether, isopropyl ether, tetrahydrofuran, acetone and the like, or in a mixed solvent.
[30] The reaction of the step (ii) is completed within 1 hour to 30 hours at a temperature in the range of 0~80°C, depending on reactivity of selected amine compounds represented by HNR R of Formula 5 and kinds of selected solvents.
[31] The present invention also provides the pharmaceutical compositions for treatment
and prevention of hepatitis C, which contains the TV-substituted-sulfamoylbenzoic acid derivatives represented by the chemical formula I and/or its pharmaceutically acceptable salts as an active ingredient.
[32] The compounds of the chemical formula I as the therapeutics for hepatitis C may be administered orally as well as through other routes in clinical uses, and can be used in form of general drugs. If it needs to be prepared, a generally used diluent including filler, builder, binder, humectant, dis -integration agent or surfactant, or excipient can be employed. In the meantime, the solid preparation for oral administration includes tablets, pills, powder, granules or capsules. This solid preparation involves more than one compound of the chemical formula I and more than one excipient, for example, starch, calcium carbonate, sucrose or lactose, or gelatin. As for the liquid preparation for oral administration, suspension, solution, oily medicine or syrup can be used, but it can also employ a simple diluent, namely water, liquid paraffin, or other kinds of excipient, e.g. humectant, sweetening agent, odorant, or preservative. As for liquid preparation for non-oral administration, sterilized water solution, non-aqueous solvent, suspension or oily medicine. Preferably used non-aqueous solvent and suspension is propylene glycol, polyethylene glycol, vegetable oil like olive oil, and injectable esters like ethyl oleate.
[33] The effective dose of the compounds of the chemical formula I is controlled depending on the patient's sex, age and condition. In general, it can be dosed to adults 10 to 1000 mg/day, more preferably 20 to 500 mg/day, or one to three times dividedly per day.
[34] Now, the present invention is explained in detail by the following examples.
However, the examples are provided for illustration of the present invention not for limitation thereof.
Advantageous Effects
[35] The novel TV-substituted-sulfamoylbenzoic acid derivatives according to the present invention represented by the chemical Formula I have excellent inhibitory effect on replication of hepatitis C virus and low cytotoxicity. Best Mode for Carrying Out the Invention
[36] Example 1: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]benzoic acid
[37] 4 g of 4-(4-morpholino)aniline and 5.45 ml of pyridine were added to 100 ml of dichloromethane, stirred to dissolve and cooled to 00C. Then, 4.95g of 4-(chlorosulfonyl)benzoic acid was added and the mixture was stirred at 0~5°C for 2 hours, followed by stirring at 20~30°C for 3 hours more. After the reaction was completed, the reaction mixture was concentrated under reduced pressure and the
residue was crystallized by 80 ml of methanol. Then, 120 ml of water was added, stirred at room temperature for 3 hours, filtered, and washed with mixed solvent of 5 ml of methanol and 25 ml of water, to give a solid product. To purify the solid product, mixed solvent of 30 ml of methanol and 150 ml of water and 6.6 ml of 3N-NaOH solution were added in sequence and stirred for 2 hours. The insoluble solid product was filtered, washed with 30 ml of water for removing impurities and crystallized by adding 6.6 ml of 3N-HC1 slowly. The mixture was stirred at room temperature for 4 hours, filtered and washed with 40 ml of water, to give a crystalline product. The product was dried in vacuo at 40~50°C to give 6.51 g of the desired compound (80% yield).
[38] m.p.: 256~258°C (dec.)
[39] 1H-NMR (DMSOd6), ppm: δ 3.00 (t, 4H), 3.68 (t, 4H), 6.78 (d, 2H), 6.85 (d, 2H),
7.77 (d, 2H), 8.04 (d, 2H), 9.98 (s, IH) Mode for the Invention
[40] Example 2: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]- N1JV '-
(dimethyl)benzamide
[41] 1 g of 4-[Λ^[4-(4-morpholino)phenyl]sulfamoyl]benzoic acid prepared in Example
1 and 0.43 ml of triethylamine were added in sequence to 50 ml of dichloromethane, stirred to dissolve and cooled to 00C. 0.36 ml of pivaloyl chloride was dropped slowly at 0~5°C and the mixture was stirred at 0~5°C for 30 minutes, followed by stirring at 20~25°C for 2 hours more. Then, 0.25 g of dimethylamine hydrochloride and 0.85 ml of triethylamine were added in sequence at 0~5°C and stirred for 1 hour at 0~5°C. After the reaction was completed, the reaction mixture was concentrated under reduced pressure and the residue was crystallized by 30 ml of methanol and 90 ml of water. The mixture was stirred at room temperature for 2 hours, filtered, washed with 20 ml of water, to give a crystalline product. The product was dried in vacuo at 35~45°C to give 0.83 g of the desired compound (77% yield).
[42] m.p.: 200~201°C
[43] 1H-NMR (DMSO-d ), ppm: δ 2.86 (s, 3H), 2.97 3.02 (m, 7H), 3.68 (t, 4H), 6.80 (d,
2H), 6.90 (d, 2H), 7.51 (d, 2H), 7.69 (d, 2H), 9.92 (s, IH)
[44]
[45] Example 3: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]- TV -
[2-(4-morpholino)ethyl]benzamide
[46] 1 g of 4-[TV-[4-(4-morpholino)phenyl]sulfamoyl]benzoic acid prepared in Example
1 and 0.85 ml of triethylamine were added in sequence to 60 ml of dichloromethane, stirred to dissolve and stirred at 20~30°C for 2 hours after adding 0.76 g of 3,5-dichloro-2-hydroxybenzenesulfonyl chloride. Then, 0.44 ml of
4-(2-aminoethyl)morpholine was added to the mixture and stirred at 20~30°C for 3 hours more. After the reaction was completed, the reaction mixture was concentrated under reduced pressure and the residue was crystallized by 20 ml of methanol and 80 ml of water. The mixture was stirred at room temperature for 4 hours, filtered, washed with 30 ml of water, to give a crystalline product. The product was dried in vacuo at 40~50°C to give 1.02 g of the desired compound (78% yield).
[47] m.p.: 208-210 0C
[48] 1H-NMR (DMSOd6), ppm: δ 2.45 (m, 6H), 2.99 (t, 4H), 3.38 (m, 2H), 3.56 (t,
4H), 3.67 (t, 4H), 6.78 (d, 2H), 6.89 (d, 2H), 7.73 (d, 2H), 7.90 (d, 2H), 8.58 (t, IH), 9.92 (s, IH)
[49]
[50] Example 4: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]- TV -
[(2-pyridyl)methyl]benzamide
[51] 1.2 g of 4-[TV-[4-(4-morpholino)phenyl]sulfamoyl]benzoic acid prepared in
Example 1 and 1.0 ml of triethylamine were added in sequence to mixed solvent of 40 ml of chloroform and 40 ml of acetonitrile, stirred to dissolve and stirred at 20~30°C for 2 hours after adding 0.91 g of 3,5-dichloro-2-hydroxybenzenesulfonyl chloride. Then, 0.4 ml of 2-(aminomethyl)pyridine was added to the mixture, heated up slowly and stirred at 50~60°C for 24 hours more. After the reaction was completed, the reaction mixture was concentrated under reduced pressure and the residue was crystallized by 25 ml of methanol and 75 ml of water. The mixture was stirred at room temperature for 5 hours, filtered, washed with 30 ml of water, to give a crystalline product. The product was dried in vacuo at 40~50°C to give 1.28 g of the desired compound (85% yield).
[52] m.p.: 202-203 0C
[53] 1H-NMR (CDCl ), ppm: δ 3.10 (t, 4H), 3.83 (t, 4H), 4.74 (d, 2H), 6.66 (s, IH),
6.74 (d, 2H), 6.93 (d, 2H), 7.23 - 7.34 (m, 2H), 7.68 - 7.76 (m, 4H), 7.89 (d, 2H), 8.55 (m, IH)
[54]
[55] Example 5: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]- TV -
[2-(3-pyridyl)ethyl]benzamide
[56] 1 g of 4-[TV-[4-(4-morpholino)phenyl]sulfamoyl]benzoic acid prepared in Example
1 and 0.85 ml of triethylamine were added in sequence to 60 ml of dichloromethane, stirred to dissolve and stirred at 20~30°C for 2 hours after adding 0.76 g of 3,5-dichloro-2-hydroxybenzenesulfonyl chloride. Then, 0.36 ml of 3-(2-aminoethyl)pyridine was added to the mixture and stirred at 20~30°C for 15 hours more. After the reaction was completed, the reaction mixture was concentrated under reduced pressure and the residue was crystallized by 20 ml of methanol and 50 ml of
water. The mixture was stirred at room temperature for 4 hours, filtered, washed with
20 ml of water, to give a crystalline product. The product was dried in vacuo at
40~50°C to give 1.03 g of the desired compound (80% yield). [57] m.p.: 204-206 0C
[58] 1H-NMR (DMSOd6), ppm: δ 2.83 (t, 2H), 2.99 (t, 4H), 3.47 (q, 2H), 3.68 (t, 4H),
6.78 (d, 2H), 6.89 (d, 2H), 7.29 (m, IH), 7.64 (d, IH), 7.72 (d, 2H), 7.86 (d, 2H), 8.40
(m, 2H), 8.74 (t, IH), 9.92 (s, IH) [59] [60] Example 6: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]- TV -
[2-(4-pyridyl)ethyl]benzamide [61] The desired compound was prepared by following the same procedure with
Example 5, except that 4-(2-aminoethyl)pyridine was substituted for
3-(2-aminoethyl)pyridine. [62] Yield: 76%
[63] m.p.: 222~225°C
[64] 1H-NMR (DMSOd6), ppm: δ 2.86 (t, 2H), 2.99 (t, 4H), 3.49 (q, 2H), 3.68 (t, 4H),
6.78 (d, 2H), 6.89 (d, 2H), 7.25 (d, 2H), 7.72 (d, 2H), 7.86 (d, 2H), 8.45 (d, 2H), 8.75
(t, IH), 9.93 (s, IH) [65] [66] Example 7: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]- TV -
[(5-methylpyrazin-2-yl)methyl]benzamide [67] The desired compound was prepared by following the same procedure with
Example 4, except that 2-(aminomethyl)-5-methylpyrazine was substituted for
2-(aminomethyl)pyridine. [68] Yield: 88%
[69] m.p.: 227~230°C
[70] 1H-NMR (DMSO-d ), ppm: δ 2.46 (s, 3H), 2.99 (t, 4H), 3.67 (t, 4H), 4.54 (d, 2H),
6.78 (d, 2H), 6.89 (d, 2H), 7.74 (d, 2H), 7.96 (d, 2H), 8.47 (m, 2H), 9.31 (t, IH), 9.93
(s, IH) [71] [72] Example 8: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]- N' JV '- bis[(2-pyridyl)methyl]benzamide [73] 1 g of 4-[TV-[4-(4-morpholino)phenyl]sulfamoyl]benzoic acid prepared in Example
1 and 0.43 ml of triethylamine were added in sequence to 60 ml of dichloromethane, stirred to dissolve and cooled to 00C. 0.36 ml of pivaloyl chloride was dropped slowly at 0~5°C and the mixture was stirred at 0~5°C for 30 minutes, followed by stirring at
20~25°C for 2 hours more. After cooling the mixture to 00C again, 0.55 ml of
2,2'-dipicolylamine and 0.43 ml of triethylamine were added in sequence at 0~5°C and
stirred at 0~5°C for 30 minutes, followed by stirring at 20~25°C for 20 hours. After the reaction was completed, the reaction mixture was washed with 60 ml of water 2 times and the separated organic layer was concentrated under reduced pressure. The residue was dissolved in 5 ml of dichloromethane and crystallized by adding 25 ml of isopropyl ether and 25 ml of hexane. The mixture was stirred at room temperature for 3 hours, filtered, washed with 10 ml of hexane, to give a crystalline product. The product was dried in vacuo at 30~35°C to give 0.9 g of the desired compound (60% yield).
[74] m.p.: 84-87 0C
[75] 1H-NMR (CDCl ), ppm: δ 3.08 (t, 4H), 3.82 (t, 4H), 4.57 (s, 2H), 4.84 (s, 2H), 6.71
(d, 2H), 6.83 (s, IH), 6.89 (m, 2H), 7.06 (d, IH), 7.18 (m, 2H), 7.37 (d, IH), 7.64 (m, 6H), 8.52 (m, 2H)
[76]
[77] Example 9: Preparation of 4-[ TV -[4-(4-morpholino)phenyl]sulfamoyl]- TV - benzyl- TV -[2-(dimethylamino)ethyl]benzamide
[78] The desired compound was prepared by following the same procedure with
Example 8, except that TV -benzyl-TV,TV-dimethylethylenediamine was substituted for 2,2'-dipicolylamine.
[79] Yield: 82%
[80] m.p.: 108- 1100C
[81] 1H-NMR (DMSO-d ), ppm: δ 1.79 (s, 4H), 2.15 (m, 3H), 2.43 (br s, IH), 2.97 (br s, 4H), 3.09 (br s, IH), 3.43 (br s, IH), 3.67 (t, 4H), 4.38 (br s, IH), 4.69 (br s, IH), 6.78 (m, 4H), 7.14 (br s, IH), 7.29 (m, 4H), 7.59 (m, 4H), 9.87 (s, IH)
[82]
[83] Experimental example 1 : Test of inhibitory effect on activity of HCV RNA
Polymerase (RNA dependent RNA polymerase. NS5B) in vitro
[84] The following in vitro experiments were conducted to examine the inhibitory effect of the compounds according to the present invention on the activity of HCV RNA dependent RNA Polymerase.
[85]
[86] Construct of recombinant HCV RNA polymerase
[87] HCV RNA polymerase was prepared as follows.
[88] HCV cDNA was obtained from the blood of HCV- Ib type HCV patient and NS5B region (1773bps) was amplified by PCR and cloned into pVLHIS, a baculovirus transfer vector, to prepare a recombinant transfer vector. The prepared transfer vector and the wild-type AcNPV vector were cotransfected into Sf 9 insect cell line to yield a recombinant baculovirus with the histidine-tagged recombinant vector pVLHIS-NS5B. Sufficiently cultured insect cells were infected with the resulting recombinant baculovirus and cultured in Grace s medium containing 10% FBS for 3 to 4 days. The
culture broth was centrifuged to obtain only the infected cells. The cells were washed three times with PBS and resuspended in binding buffer [5OmM Na-phosphate (pH 8.0), 3OmM NaCl, 1OmM imidazole, ImM DTT, 10% glycerol, 1% NP-40], sonicated and the clearized lysate was obtained. Recombinant NS5B was purified by affinity column chromatography using a Ni-NTA His bind resin (Novagen) to produce pure NS5B protein. The (His) -tagged NS5B was bound to Ni-NTA resin and washed with
6 the binding buffer containing 5OmM imidazole. The bound NS5B was eluted with the binding buffer containing imidazole in a step-gradient manner (100~300mM). The NS5B protein fractions were dialyzed against buffer [5OmM Tris-HCl, 5OmM NaCl, ImM DTT, 5mg MgCl , 10% glycerol], followed by at -70°C in a small aliquot.
[89]
[90] Construct of RNA template containing HCV 3' end (3'-UTR)
[91] The RNA template containing HCV 3' end (3'-UTR) was prepared as follows.
[92] The 3'UTR cDNA (220bp) of HCV was obtained from Ib HCV RNA of the blood of a hepatitis C patient by PCR and cloned into pcDNA3 vector. Linearized DNA fragment containing the 3'-UTR was prepared using the restriction enzyme, Eco RI and used as a template for in vitro transcription using T7 RNA ploymerase to prepare RNA fragment containing 3'-UTR.
[93]
[94] Measurement of inhibitory activity of compounds of the present invention on re- combinant HCV RNA polymerase in vitro
[95] In vitro inhibitory activity of the compounds of the present invention against re¬ combinant HCV RNA polymerase was measured as follows.
[96] A streptavidin-coated well plate was prepared suitable for the sample to be examined. 25 μl of 2x assay buffer [5OmM Tris-Cl (pH 7.5), 10OmM NaCl, 1OmM MgCl , 2OmM KCl, ImM EDTA, ImM DTT] and 10 μl of purified HCV RNA polymerase 200 ng and 3'-UTR template RNA were added to each well. Then, 5 μl of the sample to be examined was added to have final concentrations of 10, 1, 0.1 and 0.01 μg/ml. Finally, 10 μl of a reactant solution containing DIG-(digoxigenin)-UTP, biotin-UTP, ATP, CTP, GTP, and UTP as a nucleotide for the ploymerase reaction with the RNA template of HCV 3'-UTR RNA was added to each well. The reaction mixture was incubated at 22°C for 60 minutes. By the action of HCV polymerase, newly generated RNAs including UTP conjugated with biotin and DIG were copied and these new RNAs could bind to streptavidin coated on the well by biotin- conjugated UTP. After completion of the reaction, the plate was washed three times with 200 μl of a washing buffer (pH 7.0, Roche Co.) to remove unreacted substances and impurities. Then, 100 μl of the secondary antibody anti-DIG-POD (peroxidase, Roche Co.) was added to each well and incubated at 370C for 1 hour. Again, the well
plate was washed with the washing buffer. Finally, 100 μl of ABTS (Roche Co.) as a POD substrate was added to each well and reacted for 15 to 30 minutes. The optical density (OD) was measured using an ELISA reader (Bio-Tek instrument Co.) at 405nm. The inhibitory effect on the activity of HCV polymerase was calculated by subtracting the OD of the positive control without the sample. The results are shown in Table 1 below.
[97] Table 1
[98] [99] As can be seen from the above table, it is proved that the compounds according to the present invention show excellent inhibitory effects on activity of HCV RNA polymerase which plays an important role in reproduction of HCV, thereby inhibiting replication of HCV by this property. Also, the compounds according to the present invention can be advantageously used as a therapeutic or prophylactic agent of hepatitis C.
[100] [101] Experimental example 2 : cytotoxicity assay [102] The cytotoxicity of the compounds of Formula I was examined by the MTT assay, one of well-known in vitro toxicology assay methods, using Hep G2 cells. As a result, all the compounds used in the experiment were found to have CC of greater than 100 μg/ml, indicating that they are safe compounds with extremely low cytotoxicity.
Industrial Applicability
[103] As described above, the novel Λf-substituted-sulfamoylbenzoic acid derivatives according to the present invention represented by the chemical Formula I have
excellent inhibitory effect on replication of hepatitis C virus and low cytotoxicity. Therefore, they can be advantageously used as a therapeutic or prophylactic agent of hepatitis C.