WO2012109573A1 - Substituted thiazoles for use as antiviral agents - Google Patents

Abstract

Described herein are substituted thiazoles. Also described herein are preparations of substituted thiazoles, and the use of substituted thiazoles as antiviral agents.

Description

SUBSTITUTED THIAZOLES FOR USE AS ANTIVIRAL AGENTS

CROSS-REFERENCES TO RELATED APPLICATIONS

The application claims priority under 35 U.S.C. § 119(e) to U.S. Patent Application Serial No. 61/441,786, entitled "Antiviral Thiazoles," filed on February 11, 2011. The entirety of the disclosure of that application is incorporated herein by reference.

TECHNICAL FIELD

The invention described herein pertains substituted thiazoles, their preparation and their use a antiviral agents.

BACKGROUND AND SUMMARY

Flavivirus is a genus of the positive-sense single- stranded RNA family

Flaviviridae, which includes many clinically important species such as dengue, Japanese encephalitis and West Nile viruses. More than 50 million cases of dengue viral infections are reported per year in more than 80 countries in which the mosquito Aedes aegypti is endemic.¹ Of these cases, approximately 500,000 patients suffer the more severe and often lethal illnesses known as dengue hemorrhagic fever and dengue shock syndrome. (1. Munoz-Jordan, J. L.; Sanchez-Burgos, G. G; Laurent-Rolle, M..; Garcia-Sastre, A. Inhibition of Interferon Signaling by Dengue Virus. Proc. Natl. Acad. Sci. USA 2003, 100, 14333-14338.) These diseases remain a significant problem in Africa, Europe, the Middle East, and west and central Asia, where the infection is endemic, as well as in North America. Although there are a few licensed vaccines against some flavi viruses such as yellow fever and Japanese encephalitis, there are no vaccines for other types such as dengue viruses, nor effective therapy for treatment of the clinical cases. (2. Sampath, A.; Padmanabhan, R. Molecular Targets for Flavivirus Drug Discovery. Antiviral Res. 2009, Si, 6-15 and references sited within.)

There are many flaviviral proteins that could be considered as targets for drug discovery such as helicase, (3. Borowski, P.; Lang, M.; Haag, A.; Schmitz, H.; Choe, J.; Chen, H-M.; Hosmane, R. S. Characterization of Imidazo[4,5-JJPyridazine Nucleosides as

Modulators of Unwinding Reaction Mediated by West Nile Virus Nucleoside

Triphosphatase/Helicase: Evidence for Activity on the Level of Substrate and/or Enzyme. Antimicrob. Agents Chemther. 2002, 46, 1231-1239; 4. Zhang, N.; H.-Ming Chen; Koch, V.; Schmitz, H.; Minczuk, M.; Stepien, P.; Fattom, A. I.; Naso, R. B.; Kalicharran, K.; Borowski, P.; Hosmane, R. S. Potent Inhibition of NTPase/Helicase of the West Nile Virus by Ring- Expanded ("Fat") Nucleoside Analogues. J. Med. Chem. 2003, 46, 4776-4789.) methyl transferase,(5. Luzhkov, V. B.; Selisko, B.; Nordqvist, A.; Peyrane, F.; Decroly, E.; Alvarez, K.; Karlen, A.; Canard, B.; Qvist, J. A. Virtual Screening and Bioassay Study of Novel Inhibitors for Dengue Virus mRNA cap (nucleoside-2'0)-methyltransferase. Bioorg. Med. Chem. 2007, 15, 7795-7802; 6. Fabrega, C; Hausmann, S.; Shen, V.; Shuman, S.; Lima, C. D. Structure and Mechanism of mRNA Cap (Guanine-N7) Methyltransferase. Mol. Cell, 2004, 13, 77-89.) and serine protease. (7. Mueller, N. H.; Pattabiraman, N.; Ansarah-Sobrinho, C;

Viswanathan, P.; Pierson, T. C; Padmanabhan, R. Identification and Biochemical

Characterization of Small-Molecule Inhibitors of West Nile Virus Serine Protease by a High- Throughput Screen. Antimicrob. Agents Chemther. 2008, 52, 3385-3393; 8. Mueller, N. H.; Yon, C; Ganesh, V. K.; Padmanabhan, R. Characterization of the West Nile Virus Protease Substrate Specificity and Inhibitors. Int. J. Biochem. Cell Biol. 2007, 39, 606-614.) In addition, the viral RNA is also reported to be a target for some antimicrobial agents. (9. Puig-Basagoiti, F.; Tilgner, M.; Forshey, B. M.; Philpott, S. M.; Espina, N. G.; Wentworth, D. E.; Goebel, S. J.; Masters, P. S.; Falgout, B.; Ren, P.; Ferguson, D. M.; Shi, P. Triaryl Pyrazoline Compound Inhibits Flavivirus RNA Replication. Antimicrob. Agents Chemther. 2006, 50, 1320-1329.) The flaviviral E-protein plays a crucial role at the first step in viral infection, since it contains a receptor-binding site and also plays a role in fusion. It undergoes substantial conformational and translational changes through the virus replication cycle, thereby causing the native homodimer to change into a fusogenic homotrimer.( Perera, R. k.; Kuhn, R. J. Structural Proteomics of Dengue Virus, Curr. Opin. Microbio. 2008, 11, 369-377.) The dengue virus type 2 E protein has been crystallized in the presence and the absence of «-octyl- ?-D-glucoside (β-OG) (11. Modis, Y.; Ogata, S.; Clements, D.; Harrison, S.C. A Ligand-Binding Pocket in the Dengue Virus Envelope Glycoprotein. Proc. Natl. Acad. Sci. USA 2003, 100, 6986-6991.) It has been discovered herein that the preparation of antiviral agents that could occupy the β- OG pocket will lead to new anti-flavi viral agents. Without being bound by theory, it is believed herein that because the ?-OG-containing crystal structure reveals conformational changes relative to the unoccupied protein, the β-OG pocket is a valuable target for designing new anti- flaviviral agents.

It has been discovered that the compounds described herein have antiviral activity.

In one embodiment of the invention a compound of the formula

or a pharmaceutically acceptable salt thereof is described, wherein

R is CHO, carboxylic acid or derivative thereof, optionally substituted alkyl, or optionally substituted heteroaryl;

Z is CHO, a ketone, or a carboxylic acid, or a derivative of any of the foregoing; where Z is not C02Me; and

Ar is optionally substituted aryl or optionally substituted heteroaryl; and where the compound is not

where X is adamantylmethoxy or 3,4-dichlorobenzylamino.

In another embodiment, a com ound of the formula

or a pharmaceutically acceptable salt thereof, is described wherein

R is CHO, carboxylic acid or derivative thereof, optionally substituted alkyl, or optionally substituted heteroaryl;

Z is CHO or a derivative thereof, a ketone or derivative thereof, or a derivative of a carboxylic acid, or a derivative of any of the foregoing; where Z is not C02Me; and where

Z is not an ester or 3,4-dichlorobenzylamide when R is methyl; and

Ar is optionally substituted aryl or optionally substituted heteroaryl.

In another embodiment, the compound of any one of the preceding embodiments having the formula

where each of R 1 , R2 and R 3 are independently selected from hydrogen, halo, hydroxy, amino, thio, carboxylate or a derivative thereof, sulfinyl or a derivative thereof, sulfonyl or a derivative thereof, or alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heteroalkyl, heteroalkenyl, cycloheteroalkyl, cycloheteroalkenyl, aryl, heteroaryl, arylalkyl, or heteroarylalkyl, each of which is optionally substituted, wherein at least one of R 1 , R2 and R 3 is a sterically demanding or sterically hindered group, such as a branched alkyl, aryl, heteroaryl, arylalkyl, arylalkyl, or heteroarylalkyl acyl group, each of which is optionally substituted; and R⁴ is an ester bioisostere.

In another embodiment, the compound of any one of the preceding embodiments having the formula

or a pharmaceutically acceptable salt thereof is described, wherein

A = O, S, NH, CH₂;

B = hydrogen or OH, or methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, or propargyl, each of which is optionally substituted;

C = methyl, CHX₂, or CH₂X; where X = halo;

D = O, S, or aminoguanidinyl;

E = hydrogen, halo, or CH₂(CH₂)„CH₃, where n = 0-3;

F = hydrogen or halo; and

G = hydrogen or halo.

It is to be understood that A-B does not include 0-0 or O-S.

In another embodiment, the compound of any one of the preceding embodiments wherein the compound is capable of inhibiting viral replication is described.

In another embodiment, a pharmaceutical composition for treating a patient having a virus, the composition comprising one or more compounds of any one of the preceding embodiments is described.

In another embodiment, a method for treating a patient having a virus, the method comprising the step of administering to the patient a therapeutically effective amount of one or more compounds or compositions of any one of the preceding embodiments is described.

DETAILED DESCRIPTION

Several illustrative embodiments of the invention are described by the following enumerated clauses:

1. A compound of the formula

or a pharmaceutically acceptable salt thereof, wherein

R is CHO, carboxylic acid or derivative thereof, optionally substituted alkyl, or optionally substituted heteroaryl;

Z is CHO, a ketone, or a carboxylic acid, or a derivative of any of the foregoing where Z is not C02Me; and

Ar is optionally substituted aryl or optionally substituted heteroaryl; and where the compound is not

where X is adamantylmethoxy or 3,4-dichlorobenzylamino.

2. The compound of clause 1 wherein Ar is substituted phenyl.

3. The compound of clause 1 or 2 wherein Ar is phenyl substituted with one or more substituents, each independently selected from halo, hydroxy, amino, thio, carboxylate and derivatives thereof, sulfinyl and derivatives thereof, sulfonyl and derivatives thereof, phosphinyl and derivatives thereof, and phosphonyl and derivatives thereof, and alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heteroalkyl, heteroalkenyl, cycloheteroalkyl, cycloheteroalkenyl, aryl, heteroaryl, arylalkyl, and heteroarylalkyl, each of which is optionally substituted; where 2 of said substituents are optionally taken together to form heterocycle.

3a. The compound of any one of the preceding clauses wherein R is CHO, carboxylic acid or derivative thereof, substituted alkyl, or optionally substituted heteroaryl;

4. The compound of any one of clauses 1 to 3 wherein R is alkyl.

5. The compound of any one of clauses 1 to 4 wherein R is branched alkyl. 5a. The compound of any one of the preceding clauses wherein R is substituted alkyl.

5b. The compound of any one of the preceding clauses wherein R

hydroxyalkyl.

6. The compound of any one of clauses 1 to 5 wherein R is haloalkyl.

6a. The compound of any one of the preceding clauses wherein R is bromoalkyl or dibromoalkyl.

6b. The compound of any one of the preceding clauses wherein R is bromomethyl or dibromomethyl.

7. The compound of any one of clauses 1 to 6 wherein R is dibromomethyl. 8. The compound of any one of clauses 1 to 6 wherein R is dichloromethyl.

9. The compound of any one of clauses 1 to 5 wherein R is alkoxyalkyl.

10. The compound of any one of clauses 1 to 5 wherein R is alkylsulfonylalkyl.

10a. The compound of any one of clauses 1 to 5 wherein R is not alkylsulfonylalkyl.

11. The compound of any one of clauses 1 to 3 wherein R is optionally substituted heteroaryl.

12. The compound of any one of clauses 1 to 3 or 11 wherein R is unsubstituted heteroaryl.

13. The compound of any one of clauses 1 to 3, 11, or 12 wherein R is furyl.

14. The compound of any one of clauses 1 to 3 wherein R is CHO.

15. The compound of any one of clauses 1 to 3 wherein R is as ester.

16. The compound of any one of clauses 1 to 3 wherein R is cyano. 17. The compound of any one of clauses 1 to 16 wherein Z is an amide.

18. The compound of any one of clauses 1 to 16 wherein Z is a branched alkyl ester.

19. The compound of any one of clauses 1 to 16 wherein Z is a thioester. 20. The compound of any one of clauses 1 to 16 wherein Z is COCH3.

21. The compound of any one of clauses 1 to 16 wherein Z is COCHCH-Zl, where τλ is amino.

22. The compound of any one of clauses 1 to 17 wherein Z is a hydroxyalkylamide or polyhydroxyalkylamide.

23. The compound of any one of clauses 1 to 17 wherein Z is an amide of an amino saccharide.

24. The compound of any one of clauses 1 to 16 wherein Z is optionally substituted oxadiazole.

24a. The compound of any one of clauses 1 to 24 wherein Ar is 4-substituted. 24b. The compound of any one of clauses 1 to 24 wherein Ar is 4-substituted phenyl.

25. The compound of any one of clauses 1 to 24 wherein Ar is 4-chlorophenyl.

26. The compound of any one of clauses 1 to 3 wherein the compound is of the formula

or a pharmaceutically acceptable salt thereof, wherein

A = O, S, NH, CH₂;

B = hydrogen or OH, or methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, propargyl, each of which is optionally substituted;

C = methyl, CHX₂, or CH₂X; where X = halo;

D = O, S, or aminoguanidinyl;

E = hydrogen, halo, or CH₂(CH₂)„CH , where n = 0-3; F = hydrogen or halo; and

G = hydrogen or halo, wherein A-B does not include 0-0 or O-S.

26a. The compound of any one of the preceding clauses wherein C is CH₂X.

26b. The compound of any one of the preceding clauses wherein wherein X is bromo

26c. The compound of any one of the preceding clauses wherein wherein X is fluoro, chloro, or iodo.

27. The compound of clause 26 to wherein B is hydroxy or polyhydroxy substituted, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, or propargyl.

28. The compound of clause 26 or 27 wherein F and G are hydrogen.

29. The compound of any one of clauses 1 to 28 wherein the compound is capable of inhibiting viral replication.

30. The compound of any one of clauses 1 to 29 wherein the compound is capable of binding with the viral envelope protein.

31. The compound of any one of clauses 1 to 30 wherein the compound is capable of binding with the viral envelope protein and preventing the virus from continuing its life cycle.

32. A pharmaceutical composition for treating a patient having a virus, the composition comprising one or more compounds of any one of the preceding clauses.

33. The composition of clause 32 further comprising one or more carriers, diluents, or excipients, or a combination thereof.

34. A method for treating a patient having a virus, the method comprising the step of administering to the patient a therapeutically effective amount of one or more compounds or compositions of any one of the preceding clauses.

35. The method of clause 34 wherein the composition further comprises one or more carriers, diluents, or excipients, or a combination thereof.

36. The method of clause 34 or 35 wherein the virus is a flavivirus.

37. The method of any one of clauses 34 to 36 wherein the virus is a Dengue fever virus.

38. The method of any one of clauses 34 to 36 wherein the virus is a yellow fever virus.

39. The compound of any one of clauses 31 to 34 wherein the virus is a flavivirus. 40. The compound of any one of clauses 31 to 34 wherein the virus is a yellow fever virus.

41. The compound of any one of clauses 31 to 34 wherein the virus is a Dengue fever virus.

It is to be understood that as used herein, the term "treating" includes, but is not limited to, alleviating and/or preventing viral infections, including their signs and symptoms, and primary and secondary complications.

In each of the foregoing and following embodiments, it is to be understood that the formulae include and represent not only all pharmaceutically acceptable salts of the compounds, but also include any and all hydrates and/or solvates of the compound formulae. It is appreciated that certain functional groups, such as the hydroxy, amino, and like groups form complexes and/or coordination compounds with water and/or various solvents, in the various physical forms of the compounds. Accordingly, the above formulae are to be understood to include and represent those various hydrates and/or solvates. In each of the foregoing and following embodiments, it is also to be understood that the formulae include and represent each possible isomer, such as stereoisomers and geometric isomers, both individually and in any and all possible mixtures. In each of the foregoing and following embodiments, it is also to be understood that the formulae include and represent any and all crystalline forms, partially crystalline forms, and non crystalline and/or amorphous forms of the compounds.

The compounds described herein may contain one or more chiral centers, or may otherwise be capable of existing as multiple stereoisomers. It is to be understood that in one embodiment, the invention described herein is not limited to any particular sterochemical requirement, and that the compounds, and compositions, methods, uses, and medicaments that include them may be optically pure, or may be any of a variety of stereoisomeric mixtures, including racemic and other mixtures of enantiomers, other mixtures of diastereomers, and the like. It is also to be understood that such mixtures of stereoisomers may include a single stereochemical configuration at one or more chiral centers, while including mixtures of stereochemical configuration at one or more other chiral centers.

Similarly, the compounds described herein may be include geometric centers, such as cis, trans, E, and Z double bonds. It is to be understood that in another embodiment, the invention described herein is not limited to any particular geometric isomer requirement, and that the compounds, and compositions, methods, uses, and medicaments that include them may be pure, or may be any of a variety of geometric isomer mixtures. It is also to be understood that such mixtures of geometric isomers may include a single configuration at one or more double bonds, while including mixtures of geometry at one or more other double bonds.

As used herein, the term "alkyl" includes a chain of carbon atoms, which is optionally branched. As used herein, the term "alkenyl" and "alkynyl" includes a chain of carbon atoms, which is optionally branched, and includes at least one double bond or triple bond, respectively. It is to be understood that alkynyl may also include one or more double bonds. It is to be further understood that in certain embodiments, alkyl is advantageously of limited length, including Ci-C₂₄, CrC₁₂, Ci-Cg, Ci-Ce, and CrC₄. It is to be further understood that in certain embodiments alkenyl and/or alkynyl may each be advantageously of limited length, including C₂-C₂₄, C₂-C₁₂, C₂-Cg, C₂-C₆, and C₂-C₄. It is appreciated herein that shorter alkyl, alkenyl, and/or alkynyl groups may add less lipophilicity to the compound and accordingly will have different pharmacokinetic behavior. Illustrative alkyl groups are, but not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, 2- pentyl, 3-pentyl, neopentyl, hexyl, heptyl, octyl and the like.

As used herein, the term "cycloalkyl" includes a chain of carbon atoms, which is optionally branched, where at least a portion of the chain in cyclic. It is to be understood that cycloalkylalkyl is a subset of cycloalkyl. It is to be understood that cycloalkyl may be polycyclic. Illustrative cycloalkyl include, but are not limited to, cyclopropyl, cyclopentyl, cyclohexyl, 2-methylcyclopropyl, cyclopentyleth-2-yl, adamantyl, and the like. As used herein, the term "cycloalkenyl" includes a chain of carbon atoms, which is optionally branched, and includes at least one double bond, where at least a portion of the chain in cyclic. It is to be understood that the one or more double bonds may be in the cyclic portion of cycloalkenyl and/or the non-cyclic portion of cycloalkenyl. It is to be understood that cycloalkenylalkyl and cycloalkylalkenyl are each subsets of cycloalkenyl. It is to be understood that cycloalkyl may be polycyclic. Illustrative cycloalkenyl include, but are not limited to, cyclopentenyl, cyclohexylethen-2-yl, cycloheptenylpropenyl, and the like. It is to be further understood that chain forming cycloalkyl and/or cycloalkenyl is advantageously of limited length, including C₃-C₂₄, C₃-C₁₂, C₃-C8, C₃-C₆, and C5-C₆. It is appreciated herein that shorter alkyl and/or alkenyl chains forming cycloalkyl and/or cycloalkenyl, respectively, may add less lipophilicity to the compound and accordingly will have different pharmacokinetic behavior.

As used herein, the term "heteroalkyl" includes a chain of atoms that includes both carbon and at least one heteroatom, and is optionally branched. Illustrative heteroatoms include nitrogen, oxygen, and sulfur. In certain variations, illustrative heteroatoms also include phosphorus, and selenium. As used herein, the term "cycloheteroalkyl" including heterocyclyl and heterocycle, includes a chain of atoms that includes both carbon and at least one heteroatom, such as heteroalkyl, and is optionally branched, where at least a portion of the chain is cyclic. Illustrative heteroatoms include nitrogen, oxygen, and sulfur. In certain variations, illustrative heteroatoms also include phosphorus, and selenium. Illustrative cycloheteroalkyl include, but are not limited to, tetrahydrofuryl, pyrrolidinyl,

tetrahydropyranyl, piperidinyl, morpholinyl, piperazinyl, homopiperazinyl, quinuclidinyl, and the like.

As used herein, the term "aryl" includes monocyclic and polycyclic aromatic carbocyclic groups, each of which may be optionally substituted. Illustrative aromatic carbocyclic groups described herein include, but are not limited to, phenyl, naphthyl, and the like. As used herein, the term "heteroaryl" includes aromatic heterocyclic groups, each of which may be optionally substituted. Illustrative aromatic heterocyclic groups include, but are not limited to, pyridinyl, pyrimidinyl, pyrazinyl, triazinyl, tetrazinyl, quinolinyl, quinazolinyl, quinoxalinyl, thienyl, pyrazolyl, imidazolyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl, triazolyl, benzimidazolyl, benzoxazolyl, benzthiazolyl,

benzisoxazolyl, benzisothiazolyl, and the like.

As used herein, the term "amino" includes the group NH₂, alkylamino, and dialkylamino, where the two alkyl groups in dialkylamino may be the same or different, i.e. alkylalkylamino. Illustratively, amino includes methylamino, ethylamino, dimethylamino, methylethylamino, and the like. In addition, it is to be understood that when amino modifies or is modified by another term, such as aminoalkyl, or acylamino, the above variations of the term amino are included therein. Illustratively, aminoalkyl includes H₂N-alkyl, methylaminoalkyl, ethylaminoalkyl, dimethylaminoalkyl, methylethylaminoalkyl, and the like. Illustratively, acylamino includes acylmethylamino, acylethylamino, and the like.

As used herein, the term "amino and derivatives thereof includes amino as described herein, and alkylamino, alkenylamino, alkynylamino, heteroalkylamino,

heteroalkenylamino, heteroalkynylamino, cycloalkylamino, cycloalkenylamino,

cycloheteroalkylamino, cycloheteroalkenylamino, arylamino, arylalkylamino,

arylalkenylamino, arylalkynylamino, heteroarylamino, heteroarylalkylamino,

heteroarylalkenylamino, heteroarylalkynylamino, acylamino, and the like, each of which is optionally substituted. The term "amino derivative" also includes urea, carbamate, and the like. As used herein, the term "hydroxy and derivatives thereof includes OH, and alkyloxy, alkenyloxy, alkynyloxy, heteroalkyloxy, heteroalkenyloxy, heteroalkynyloxy, cycloalkyloxy, cycloalkenyloxy, cycloheteroalkyloxy, cycloheteroalkenyloxy, aryloxy, arylalkyloxy, arylalkenyloxy, arylalkynyloxy, heteroaryloxy, heteroarylalkyloxy,

heteroarylalkenyloxy, heteroarylalkynyloxy, acyloxy, and the like, each of which is optionally substituted. The term "hydroxy derivative" also includes carbamate, and the like.

As used herein, the term "thio and derivatives thereof includes SH, and alkylthio, alkenylthio, alkynylthio, heteroalkylthio, heteroalkenylthio, heteroalkynylthio, cycloalkylthio, cycloalkenylthio, cycloheteroalkylthio, cycloheteroalkenylthio, arylthio, arylalkylthio, arylalkenylthio, arylalkynylthio, heteroarylthio, heteroarylalkylthio,

heteroarylalkenylthio, heteroarylalkynylthio, acylthio, and the like, each of which is optionally substituted. The term "thio derivative" also includes thiocarbamate, and the like.

As used herein, the term "acyl" includes formyl, and alkylcarbonyl, alkenylcarbonyl, alkynylcarbonyl, heteroalkylcarbonyl, heteroalkenylcarbonyl,

heteroalkynylcarbonyl, cycloalkylcarbonyl, cycloalkenylcarbonyl, cycloheteroalkylcarbonyl, cycloheteroalkenylcarbonyl, arylcarbonyl, arylalkylcarbonyl, arylalkenylcarbonyl,

arylalkynylcarbonyl, heteroarylcarbonyl, heteroarylalkylcarbonyl, heteroarylalkenylcarbonyl, heteroarylalkynylcarbonyl, acylcarbonyl, and the like, each of which is optionally substituted.

As used herein, the term "carbonyl and derivatives thereof includes the group C(O), C(S), C(NH) and substituted amino derivatives thereof.

As used herein, the term "carboxylate and derivatives thereof includes the group C0₂H and salts thereof, and esters and amides thereof, and CN.

Additional illustrative derivatives of carboxylic acids Z are disclosed in (13. a) Saunders, J.; Cassidy, M.; Freedman, S. B.; Harley, E. A.; Iversen, L. L.; Kneen, C; MacLeod, A. M.; Merchant, K. J.; Snow, R. J.; Baker, R. Novel Quinuclidine-based Ligands for the Muscarinic Cholinergic Receptor. /. Med. Chem. 1990, 33, 1128-1138; b) Orlek, B. S.;

Blaney, F. E.; Brown, F.; Clark, M. S. G.; Hadley, M. S.; Hatcher, J.; Riley, Graham J.;

Rosenberg, H. E.; Wadsworth, H. J.; Wyman, P. Comparison of Azabicyclic Esters and Oxadiazoles as Ligands for the Muscarinic Receptor. /. Med. Chem. 1991, 34, 2726-2735; c) Sakamoto, T.; Cullen, M. D.; Hartman, T. L.; Watson, K. M.; Buckheit, R. W.; Pannecouque, C; De Clercq, E.; Cushman, M. Synthesis and Anti-HIV Activity of New Metabolically Stable Alkenyldiarylmethane Non-Nucleoside Reverse Transcriptase Inhibitors Incorporating N- Methoxy Imidoyl Halide and 1,2,4-Oxadiazole Systems. /. Med. Chem. 2007, 3314-3321.), the disclosures of which are incorporated herein by reference.

As used herein, the term "sulfinyl or a derivative thereof includes S0₂H and salts thereof, and esters and amides thereof.

As used herein, the term "sulfonyl or a derivative thereof includes SO₃H and salts thereof, and esters and amides thereof.

As used herein, the term "phosphinyl or a derivative thereof includes P(R)0₂H and salts thereof, and esters and amides thereof, where R is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heteroalkyl, heteroalkenyl, cycloheteroalkyl, cycloheteroalkenyl, aryl, heteroaryl, arylalkyl, or heteroarylalkyl, each of which is optionally substituted.

As used herein, the term "phosphonyl or a derivative thereof includes P0₃H₂ and salts thereof, and esters and amides thereof.

As used herein, the term "hydroxylamino and derivatives thereof includes NHOH, and alkyloxylNH alkenyloxylNH alkynyloxylNH heteroalkyloxylNH

heteroalkenyloxylNH heteroalkynyloxylNH cycloalkyloxylNH cycloalkenyloxylNH

cycloheteroalkyloxylNH cycloheteroalkenyloxylNH aryloxylNH arylalkyloxylNH

arylalkenyloxylNH arylalkynyloxylNH heteroaryloxylNH heteroarylalkyloxylNH

heteroarylalkenyloxylNH heteroarylalkynyloxylNH acyloxy, and the like, each of which is optionally substituted.

As used herein, the term "hydrazino and derivatives thereof includes alkylNHNH, alkenylNHNH, alkynylNHNH, heteroalkylNHNH, heteroalkenylNHNH, heteroalkynylNHNH, cycloalkylNHNH, cycloalkenylNHNH, cycloheteroalkylNHNH, cycloheteroalkenylNHNH, arylNHNH, arylalkylNHNH, arylalkenylNHNH,

arylalkynylNHNH, heteroarylNHNH, heteroarylalkylNHNH, heteroarylalkenylNHNH, heteroarylalkynylNHNH, acylNHNH, and the like, each of which is optionally substituted.

The term "optionally substituted" as used herein includes the replacement of hydrogen atoms with other functional groups on the radical that is optionally substituted. Such other functional groups illustratively include, but are not limited to, amino, hydroxyl, halo, thiol, alkyl, haloalkyl, heteroalkyl, aryl, arylalkyl, arylheteroalkyl, heteroaryl, heteroarylalkyl, heteroarylheteroalkyl, nitro, sulfonic acids and derivatives thereof, carboxylic acids and derivatives thereof, and the like. Illustratively, any of amino, hydroxyl, thiol, alkyl, haloalkyl, heteroalkyl, aryl, arylalkyl, arylheteroalkyl, heteroaryl, heteroarylalkyl, heteroarylheteroalkyl, and/or sulfonic acid is optionally substituted.

As used herein, the terms "optionally substituted aryl" and "optionally substituted heteroaryl" include the replacement of hydrogen atoms with other functional groups on the aryl or heteroaryl that is optionally substituted. Such other functional groups illustratively include, but are not limited to, amino, hydroxy, halo, thio, alkyl, haloalkyl, heteroalkyl, aryl, arylalkyl, arylheteroalkyl, heteroaryl, heteroarylalkyl, heteroarylheteroalkyl, nitro, sulfonic acids and derivatives thereof, carboxylic acids and derivatives thereof, and the like. Illustratively, any of amino, hydroxy, thio, alkyl, haloalkyl, heteroalkyl, aryl, arylalkyl, arylheteroalkyl, heteroaryl, heteroarylalkyl, heteroarylheteroalkyl, and/or sulfonic acid is optionally substituted.

Illustrative substituents include, but are not limited to, a radical -(CH₂)_xZ , where x is an integer from 0-6 and Z is selected from halogen, hydroxy, alkanoyloxy, including C -C alkanoyloxy, optionally substituted aroyloxy, alkyl, including C -C alkyl, alkoxy, including C -C alkoxy, cycloalkyl, including C₃-C₈ cycloalkyl, cycloalkoxy, including C₃-C₈ cycloalkoxy, alkenyl, including C₂-C₆ alkenyl, alkynyl, including C₂-C₆ alkynyl, haloalkyl, including CrC₆ haloalkyl, haloalkoxy, including CrC₆ haloalkoxy, halocycloalkyl, including C₃-C₈ halocycloalkyl, halocycloalkoxy, including C₃-C₈ halocycloalkoxy, amino, Ci- Ce alkylamino, (C -C alkyl)(Ci-C₆ alkyl)amino, alkylcarbonylamino, N-(Ci-C₆

alkyl)alkylcarbonylamino, aminoalkyl, CrC₆ alkylaminoalkyl, (CrC₆ alkyl)(Ci-C₆

alkyl)aminoalkyl, alkylcarbonylaminoalkyl, N-(CrC₆ alkyl)alkylcarbonylaminoalkyl, cyano, and nitro; or Z^x is selected from -C0₂R⁴ and -CONR⁵R⁶, where R⁴, R⁵, and R⁶ are each independently selected in each occurrence from hydrogen, C -C alkyl, aryl-Ci-C₆ alkyl, and heteroaryl-Ci-C6 alkyl.

The term "therapeutically effective amount" as used herein, refers to that amount of active compound or pharmaceutical agent that elicits the biological or medicinal response in a tissue system, animal or human that is being sought by a researcher, veterinarian, medical doctor or other clinician, which includes alleviation of the symptoms of the disease or disorder being treated. In one aspect, the therapeutically effective amount is that which may treat or alleviate the disease or symptoms of the disease at a reasonable benefit/risk ratio applicable to any medical treatment. However, it is to be understood that the total daily usage of the compounds and compositions described herein may be decided by the attending physician within the scope of sound medical judgment. The specific therapeutically-effective dose level for any particular patient will depend upon a variety of factors, including the disorder being treated and the severity of the disorder; activity of the specific compound employed; the specific composition employed; the age, body weight, general health, gender and diet of the patient: the time of administration, route of administration, and rate of excretion of the specific compound employed; the duration of the treatment; drugs used in combination or coincidentally with the specific compound employed; and like factors well known to the researcher, veterinarian, medical doctor or other clinician of ordinary skill.

As used herein, the term "composition" generally refers to any product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combinations of the specified ingredients in the specified amounts. It is to be understood that the compositions described herein may be prepared from isolated compounds described herein or from salts, solutions, hydrates, solvates, and other forms of the compounds described herein. It is also to be understood that the compositions may be prepared from various amorphous, non-amorphous, partially crystalline, crystalline, and/or other morphological forms of the compounds described herein. It is also to be understood that the compositions may be prepared from various hydrates and/or solvates of the compounds described herein. Accordingly, such pharmaceutical compositions that recite compounds described herein are to be understood to include each of, or any combination of, the various morphological forms and/or solvate or hydrate forms of the compounds described herein. Illustratively, compositions may include one or more carriers, diluents, and/or excipients. The compounds described herein, or compositions containing them, may be formulated in a therapeutically effective amount in any conventional dosage forms appropriate for the methods described herein. The compounds described herein, or compositions containing them, including such formulations, may be administered by a wide variety of conventional routes for the methods described herein, and in a wide variety of dosage formats, utilizing known procedures (see generally, Remington: The Science and Practice of Pharmacy, (21^st ed., 2005)).

The term "administering" as used herein includes all means of introducing the compounds and compositions described herein to the patient, including, but are not limited to, oral (po), parenteral, intravenous (iv), intramuscular (im), subcutaneous (sc), transdermal, inhalation, and the like. The compounds and compositions described herein may be administered in unit dosage forms and/or formulations containing conventional nontoxic pharmaceutically-acceptable carriers, adjuvants, and vehicles.

In making the pharmaceutical compositions of the compounds described herein, a therapeutically effective amount of one or more compounds in any of the various forms described herein may be mixed with one or more excipients, diluted by one or more excipients, or enclosed within such a carrier which can be in the form of a capsule, sachet, paper, or other container. Excipients may serve as a diluent, and can be solid, semi-solid, or liquid materials, which act as a vehicle, carrier or medium for the active ingredient. Thus, the formulation compositions can be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosols (as a solid or in a liquid medium), ointments, soft and hard gelatin capsules, suppositories, sterile injectable solutions, and sterile packaged powders. The compositions may contain anywhere from about 0.1% to about 99.9% active ingredients, depending upon the selected dose and dosage form.

Some examples of suitable excipients include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water, syrup, and methyl cellulose. The formulations can additionally include: lubricating agents such as talc, magnesium stearate, and mineral oil; wetting agents; emulsifying and suspending agents;

preserving agents such as methyl- and propylhydroxybenzoates; sweetening agents; and flavoring agents. The compositions can be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the patient by employing procedures known in the art. It is appreciated that the carriers, diluents, and excipients used to prepare the compositions described herein are advantageously GRAS (generally regarded as safe) compounds.

Examples of emulsifying agents are naturally occurring gums (e.g., gum acacia or gum tragacanth) and naturally occurring phosphatides (e.g., soybean lecithin and sorbitan monooleate derivatives). Examples of antioxidants are butylated hydroxy anisole (BHA), ascorbic acid and derivatives thereof, tocopherol and derivatives thereof, butylated hydroxy anisole, and cysteine. Examples of preservatives are parabens, such as methyl or propyl p- hydroxybenzoate, and benzalkonium chloride. Examples of humectants are glycerin, propylene glycol, sorbitol, and urea. Examples of penetration enhancers are propylene glycol, DMSO, triethanolamine, N,N-dimethylacetamide, Ν,Ν-dimethylformamide, 2-pyrrolidone and derivatives thereof, tetrahydrofurfuryl alcohol, and AZONE. Examples of chelating agents are sodium EDTA, citric acid, and phosphoric acid. Examples of gel forming agents are

CARBOPOL, cellulose derivatives, bentonite, alginates, gelatin and polyvinylpyrrolidone. Examples of ointment bases are beeswax, paraffin, cetyl palmitate, vegetable oils, sorbitan esters of fatty acids (Span), polyethylene glycols, and condensation products between sorbitan esters of fatty acids and ethylene oxide (e.g., polyoxyethylene sorbitan monooleate (TWEEN)). Also described herein is the synthesis of several phenylthiazole structural analogues. Also described herein are the effects of C4 and/or C5 substitution (references to positions C4 and C5 refer to the 4- and 5- position of the thiazole ring, unless otherwise indicated,) on the antiviral activity.

Described herein are compounds in which the dibromomethyl and methyl ester moieties are replaced by a variety of substituents. Without being bound by theory, it is believet herein that the methyl ester moiety may be metabolically labile to non-specific esterases in blood plasma and the corresponding free acid analogue has already been established in many cases to be a substantially less active compound. Also described herein are compounds in which the methyl ester at C5 has been replaced by bioisosteres, including but not limited to amides, thioesters, ketones and more sterically bulky or demanding esters, which without being bound by theory are believed herein to be more metabolically stable.

It has been discovered that certain free acid analogs of the compounds described herein, where Z is CO2H, are substantially less active. It has also been discovered herein that the methyl ester analogs of the compounds described herein, where Z is CC^Me, are unstable in vivo. Without being bound by theory, it is believed herein that the methyl ester analogs may be substrates for non-specific esterases in blood plasma. Such metabolic lability may result in low bioavailability, drug half-lives that are too short, or other undesirably pharmacokinetic property.

The compounds described herein where Z is CHO or a derivative thereof, a ketone, or a derivative thereof, or a derivative of a carboxylic acid, but where Z is not CC^Me exhibit improved pharmacokinetics compared to the methyl esters.

Described herein are compounds where Z is a methyl ketone or methyl and ethyl thioester analogues (structures 20, 16, and 15). Both ketone 20 (EC₅₀ 1.3 μΜ) and ethyl thioester 15 (EC₅₀ 1.6 μΜ) derivatives display approximately double the antiviral potency compared with analogous methyl esters. The methyl thioester 16 (EC₅₀ 1.4 μΜ, GI₅o 368.7 μΜ) displays high antiviral potency and low cytotoxicity in uninfected cells compared with analogous methyl esters, resulting in a high therapeutic index (TI) for 16 of 263. It has been described that the metabolic stability of a methyl thioester in the rat plasma can, in some cases, be higher than that of the corresponding ester.(17. Cullen, M. D.; Deng, B.; Hartman, T. L.; Watson, K. M.; Buckheit, R. W.; Pannecouque, Jr. C; De Clercq, E.; Cushman, M. Synthesis and Biological Evaluation of Alkenyldiarylmethane HIV-1 Non-Nucleoside Reverse

Transcriptase Inhibitors That Possess Increased Hydrolytic Stability. /. Med. Chem. 2007, 50, 4854-4867.) Compound 16 was subjected to hydrolytic stability analysis utilizing lyophilized rat plasma. The half-life of compound 16 was found to be 24.7 hours, which is many fold higher compared with analogous methyl esters. Compound 16 provided good metabolic stability, antiviral potency, low cytotoxicity, and a good TI.

It has also been discovered herein that amide, ketone, and thioester derivatives exhibit better antiviral activity and high metabolic stability compared with analogous methyl esters.

It is also observed that compounds with N- and O-hydrophobic substitutions may decrease the antiviral activity. Without being bound by theory, it is believed that this portion of the compounds lies in a hydrophilic region within the binding pocket or faces the solvent-accessible surface. Described herein are compounds which include hydrophilic moieties on the alkyl side chain. Among the ester isosteres that showed significant antiviral activity, the amide group modified to include hydroxy- and sugar- groups. Amides with a variable number of hydroxy groups were synthesized (Scheme 3). Compound 23, which contains two hydroxyl groups, revealed an EC₅₀ of 1.1 μΜ, which is many fold better than analogous methyl esters. Removal of the terminal hydroxymethyl group afforded compound 22, which displayed a higher EC₅₀ value. Compounds 24 and 25 revealed lower biological activity than 23.

It has been discovered herein that the higher activity of compound 23 may be explained from molecular modeling. The modeling was performed using the published structure of the dengue virus envelope protein, which it is believed to be valid is this case because the sequence alignment of the dengue virus protein vs. the yellow fever virus protein reveals that they have 45% identity and 61% similarity.(18. a) Burke, D. S.; Monath, T. (2001). Flavi viruses. Philadelphia Lippincott Williams and Wilkins. b) Bressanelli, S.; Stiasny, K.; Allison, S. L.; Stura, E. A.; Duquerroy, S.; Lescar, J.; Heinz, F. X.; Rey, F. A. Structure of a Flavivirus Envelope Glycoprotein in Its Low-/?H-Induced Membrane Fusion Conformation. EMBO J. 2004, 23, 728-738.) Among flaviviruses, the envelope proteins are predicted to be very similar in their overall fold and domain arrangement, including the hinge region, which is highly conserved.

Although the structural details of the binding of the compounds described herein to its receptor are not known with certainty, molecular modeling and docking studies suggested the possibility for two distinct docking poses having a very small calculated energy difference. One docking pose of is substantially parallel to a docked structure of β-OG in the dengue viral 2 E protein β-OG binding pocket. The other pose is substantially anti-parallel to the docked structure of β-OG.

In another embodiment, compounds are described herein that are capable of interacting with predetermined residues of viruses. Illustratively, compounds are described herein that are capable of interacting with one or more residues of Dengue viral 2 E protein, including but not limited to Ser274, Gln271, and Gln200. Such interaction may be determined and assessed using a variety of computational methods, including molecular modeling and molecular docking, as well as empirical methods, including X-ray crystallography. In a modeling study, the terminal hydroxy group of the dihydroxypropyl moiety of 23 is calculated to have a binding pose that is close to that of the sugar moiety of β-OG. It is calculated to form two hydrogen bonds with Ser274 and Gln271, which contribute to the binding energy of 23 and consequently its inhibitory activity. The distance to Ser274 is calculated to be about 2.6 A and the distance to Gln271 is calculated to be about 2.8 A

Also described herein are modifications of the group attached to thiazole-C4 position. A series of thiazole-C4-modified derivatives were designed and prepared with varying steric and the electronic properties. Described herein are compounds where the C4- modifications include alkyl and aryl substituents (compounds 28-31).

Compounds wherein more polar moieties are attached at C-4 of the thiazole (Chart 1) generally showed higher EC₅₀ values, with the exception of compound 33 (Table 1, compounds 32-36, 40-45).

Adding a hydrogen bond acceptor moiety at the thiazole-C4 position is described herein. From docking studies , two glutamine residues in the envelope protein appear to be possible targets for hydrogen bonding interactions with a group attached to the C4-thiazole position. In the case of amide analogue 24, the binding pose that is parallel to the β-OG molecule indicated the possibility of hydrogen bond formation between the

dibromomethyl moiety and both Gln200 residue (3.3 A and 3.9 A. The same observation was found. Replacement of the dibromomethyl moiety by a sulfinyl (S0₂) moiety, in which the two oxygen atoms are available to make two distinct hydrogen bonds with the glutamine residues, is described. When this proposed compound was docked in the β-OG site, the oxygens of the S0₂ moiety were not near the glutamine residues. In contrast, adding one CH₂ unit between the sulfinyl moiety and thiazole ring (compound 39) was calculated to place the two oxygen atoms closer to the target residues. It was surprisingly found that compound 39 appears to stimulate viral replication instead of inhibiting it (Table 1). Compounds containing other haloalkyl groups at the C4-thiazole position are described herein. The dichloromethyl analogue 37 had weak antiviral activity. The

monobromo derivative 38 showed an improved EC₅₀ value of 1.6 μΜ compared with analogous methyl esters. The cytotoxicity of compound 38 was in an acceptable range (GI₅₀ > 40 μΜ).

The following abbreviations are used herein: BHK, baby hamster kidney cells; β-OG, «-octyl- ?-D-glucoside; EMCV, encephalomyocarditis virus; E-protein, Envelop-protein; FBS, fetal bovine serum; Luc, luciferase; MEM, minimal essential medium; NBS, N- bromosuccinimide; NCS, N-chlorosuccinimide; PCR, polymerase chain reaction; SARs, structure-activity relationships; TI, therapeutic index; YFV, yellow fever virus; IRES, internal ribosome entry site.

Acid chloride 4 served as a key intermediate for the replacement of the metabolically labile ester with more stable bioisosteres. As shown in Scheme 1, two pathways were used to synthesize it. Hydrolysis of ester 1 gave a low yield of the corresponding free acid because, under the reaction conditions, the carboxylate salt formed in situ underwent SN2 reaction with the adjacent alkyl bromide, forming a cyclic lactone by-product. Bromination of the acid chloride 3, utilizing NBS and UV light as a free radical initiator, gave the dibromo acid chloride derivative 4 in a good yield with no detectable mono or tribromo by-products. The 1H NMR spectrum of compound 4 revealed three signals, one singlet and two doublets, at δ 7.30, 7.49 and 8.01 ppm, corresponding to the methine and 1,4-disubstituted phenyl moieties, respectively.

Synthesis of the amide derivatives 5-12 was accomplished by reacting acid chloride 4, with primary or secondary amines in dichloromethane, or with ammonia solution at room temperature for 5-10 min (Scheme 1). The esters were prepared by dissolving acid chloride 4 in the corresponding alcohols (Scheme 1). Similarly, treatment of acid chloride 4 with alkanethiols or their sodium salts afforded the corresponding thioesters as depicted in Scheme 1.

In order to synthesize derivative 20, containing dibromomethyl and methylketo functionalities, the methyl ketone 19 was prepared by utilizing thioamide 18 and the appropriate diketo derivative 17 (Scheme 2). It was discovered that efficient dibromination of the C4 methyl group without detectable bromination of the methyl of the C5 acetyl group required careful control of the amount of NBS used (two equivalents), the solvent (CC1₄), and free radical initiation (UV irradiation). Using other chemical-free radical initiators afforded mixtures of different brominated compounds. The site of bromination was assigned to be the C5-methyl , and not the acetyl methyl, based on spectral data. For instance, the C5-methyl carbon signal of 19 at 18.34 ppm was not present in the 13 C NMR spectrum of the product 20, which revealed only two signals corresponding to dibromomethyl and acylmethyl groups at 32.00 and 31.28 ppm in the aliphatic region. In addition, the mass spectrum showed a base peak at m/z 395, which is believed to correspond to the acylium cation (M⁺ - CH₃).

Amide derivatives with hydroxyalkyl or carbohydrate moieties were prepared by treatment of acid chloride 4 with the appropriate amines in DMF (Scheme 3). To synthesize the thiazole-C4 derivatives, chlorination of the commercially available dicarbonyl compounds 26a-c was performed using sulfuryl chloride to afford the corresponding a-chloro derivatives 27a-d in high yields (Scheme 4). The 1H NMR spectra of these compounds exhibited singlets at approximately δ 5 ppm believed to be due to the methine proton. Treatment of the a-chloro derivatives with 4-chlorobenzothioamide (18) in ethanol afforded, in each case, the

corresponding 2-(p-chlorophenyl)thiazole derivatives 28-31 (Scheme 4).

Two approaches to prepare phenylthiazoles with hydrogen bond acceptor moieties at position 4, two approaches are described herein. The first included treatment of the ether 33 with one equivalent of NBS under free radical conditions to afford the corresponding aldehyde 34 as reported by Markees (Scheme 5). (15. Markees, D. J.; Reaction of Benzyl Methyl Ethers with Bromine and N-Bromosuccinimide. /. Org. Chem. 1958, 23, 1490-1492.) To prepare methyl esters 40, 43, and 45 (Chart 1), a modified version of the Markees procedure was used, as previously reported.(16. Mayhoub, A. S.; Talukdar, A.; Cushman, M. Oxidation of Benzyl Methyl Ethers with NBS Selectively Affords Either Aromatic Aldehydes or Aromatic Methyl Esters. /. Org. Chem. 2010, 75, 3507-3510.)

Aldehyde derivative 35 was treated with acetyl chloride and a catalytic amount of A1C1₃ to afford the dichloromethyl derivative 37, which could not be obtained by treatment of 2 with NCS (Scheme 6). The nitrile derivative 36 was obtained from the reaction of the corresponding aldehyde 35 and ammonia solution. Oxidation of the imine intermediate in situ by elemental iodine provided the required nitrile in quantitative yield (Scheme 6). The sulfone derivative 39 was obtained from the corresponding monobromo derivative 38 (Scheme 7).

The thiazole derivatives are evaluated in a yellow fever virus luciferase cellular assay. Without being bound by theory, it is believed herein that modification of R⁴ at thiazole- C5 may contribute to both the increase in metabolic stability and potency compared to analogous methyl esters. Described herein is the replacement of the ester group by groups that could be more metabolically stable such as, but not limited to, amides, thioesters, or ketones. Described herein are amides (Scheme 2), the unsubstituted amide 6 and the methyl amide derivative 8 revealed better EC₅₀ values compared with analogous methyl esters (Table 1). Increasing the alkyl chain length, from methyl to ethyl, retained the potency, but the toxicity was increased (Table 1, compound 11). On the other hand, increasing the side chain polarity by replacement of the ethyl group in compound 11 by a methoxy group improved the antiviral activity (compound 5). Tertiary amides, such as 7 and 9, showed 5-10-fold lower activity. Replacement of the methyl group of 8 with an allyl group (compound 10) did not improve the potency. Further increasing the unsaturation led to an increase in the toxicity (compound 12).

Without being bound by theory, it is believed that comparison of the EC₅₀ values for the secondary amide 8 (EC₅₀ 1.8 μΜ) vs. the corresponding tertiary amide 7 (EC₅₀ 20 μΜ), as well as the secondary amide 11 (EC₅₀ 2.7 μΜ) vs. the corresponding tertiary amide 9 (EC₅₀ 13.7 μΜ), suggests that removing the hydrogen bond-donating ability of the amide and/or increasing its hydrophobicity and steric bulk decreases the antiviral activity. The ethyl ester 13 (EC₅₀ 8.7 μΜ) and the isopropyl ester 14 (EC₅₀ 19.9 μΜ) were synthesized and compared with the methyl ester 1 (EC₅₀ 2.8 μΜ). Without being bound by theory, it is believed that the results obtained with esters 1, 13, and 14 are consistent with a correlation of decreased antiviral activity with an increase in hydrophobicity. It is believed that these observations are consistent with a hydrophobic ally and sterically unfavorable region of the envelope protein surrounding the C-5 substituent of the ligand.

The following examples further illustrate specific embodiments of the invention; however, the following illustrative examples should not be interpreted in any way to limit the invention. METHODS AND EXAMPLES

All biologically tested compounds had purity > 95% as established by HPLC.

1 H NMR spectra were run at 300 MHz and 13 C spectra were determined at 75.46 MHz in deuterated chloroform (CDCI₃), dimethyl sulfoxide (DMSO- g), methanol (CD₃OD) or acetone (CD₃COCD₃). Chemical shifts are given in parts per million (ppm) on the delta (δ) scale.

Chemical shifts were calibrated relative to those of the solvents. Mass spectra were recorded at 70 eV. All reactions were conducted under argon or nitrogen atmosphere, unless otherwise specified. Compound 2,¹³ 3,¹⁹ 27a,²⁰ 27b,²¹ 22, 32, 35, and 40-45¹⁷ were prepared according to the reported procedures. (19. Csavassy, G.; Gyorfi, Z. A. Thiazole Compounds. I. Synthesis and Reactions of 2-Aryl-5-(diazoacetyl)-4-methylthiazoles. Justus Liebigs Ann. Chem.

1974, 8, 1195-1205.; 20. De Kimpe, N.; De Cock, W.; Schamp, N. A Convenient Synthesis of l-Chloro-2-alkanones. Synthesis 1987, 2, 188-190.; 21. Sreedhar, B.; Reddy, P. S.; Madhavi, M. Rapid and Catalyst-Free a-halogenation of Ketones Using N-Halosuccinimides in DMSO. Synth. Commun. 2007, 37, 4149-4156.)

4-(Dibromomethyl)-5-chlorocarbonyl-2-(4-chlorophenyl)thiazole (4). Method A: 5-Chlorocarbonyl-(4-chlorophenyl)-4-methylthiazole (3) (3.538 g, 13 mmol) and NBS (20.7 g, 78 mmol) were added to CC1₄ (75 mL). The reaction mixture was heated at reflux for 48 h and irradiated with UV light (produced from a sun-lamp) ten times (5 min every 30 min). The yellowish- white precipitate was purified by silica gel chromatography (ethyl acetate -hexanes 1: 1) to provide the compound as a white solid (3.55 g, 63.7%). Method B: NaOH (80 mg, 2 mmol) was added to a solution of methyl ester 1 (423 mg, 1 mmol) in methanol (20 mL) and water (5 mL). The reaction mixture was heated at reflux for 6 h and then allowed to cool to room temperature. The reaction mixture was filtered and the pH of the liquid phase was adjusted to 2 with hydrochloride acid. The solid was filtered and dried and purified by silica gel chromatography (hexanes-ethyl acetate- glacial acetic acid 50:49: 1) to provide the carboxylic acid. The free acid (411 mg, 1 mmol) was heated at reflux with thionyl chloride (7 mL) for 2 h. The solvent was evaporated under pressure. The pale yellow residue was collected and recrystallized from chloroform to yield a white solid product (231.7 mg, 53%): mp 131-132°C. 1H NMR (CDC1₃) δ 8.01 (d, J = 8.7 Hz, 2 H), 7.49 (d, J = 8.7 Hz, 2 H), 7.30 (s, 1 H); ¹³C NMR (CDCI₃) δ 167.43, 155.31, 136.57, 131.21, 128.83, 127.67, 122.44; CIMS m/z (rel intensity) 432/430/428 (MH⁺, 40/45/41), 352/350/348 (M⁺ - Br, 26/100/38); HRMS (CI), m/z 347.8652 (M - HBr)⁺, calcd for CnHsBrClaNOS 347.8647.

Preparation of Amide Derivatives 5 and 7-12. The acid chloride 4 (430 mg, 1 mmol) was suspended in dry CH₂CI₂ (5 mL) under argon, amine (2 mmol) was added and the mixture was stirred at room temperature for 2-10 min. Aqueous HC1 (0.5 M, 15 mL) was added, and the solution was extracted with ethyl acetate (30 mL). The crude residue obtained after evaporation of solvent was purified by silica gel flash chromatography using hexane-ethyl acetate (1: 1) to afford the product.

4-(Dibromomethyl)-2-(4-chlorophenyl)-N-methoxythiazole-5-carboxamide (5).

Off-white solid (7.1 mg, 11%): 85°C. IR (film) 3584, 3047, 2960, 1715, 1593 cm^"1; 1H NMR (CDCI₃) δ 7.98 (d, J = 7.5 Hz, 2 H), 7.69 (s, 1 H), 7.45 (d, J = 8.7 Hz, 2 H), 3.94 (s, 3 H); ¹³C NMR (CDCI₃) δ 170.09, 161.35, 158.90, 137.85, 130.60, 129.36, 128.27, 52.93, 31.01; MS m/z (rel intensity) 443/441/439 (MH⁺, 51/100/31), 394 (36); HRMS (ESI) m/z 438.8514 MH⁺, calcd for C₁₂HioBr₂ClN₂0₂S 438.8513; HPLC purity 98.36%.

4-(Dibromomethyl)-2-(4-chlorophenyl)-N,N-dimethylthiazole-5-carboxamide (7). White solid (51.1 mg, 83%): mp 63-64°C. 1H NMR (CDC1₃) δ 7.93 (d, J = 8.4 Hz, 2 H), 7.43 (d, J = 8.4 Hz, 2 H), 6.87 (s, 1 H), 3.11 (s, 6 H); ¹³C NMR (CDC1₃) δ 166.50, 161.42, 153.57, 137.42, 130.60, 129.28. 128.06, 123.76, 39.72, 31.14, 31.27; MS m/z (rel intensity) 441/439/437 (MH⁺, 11.2/15.4/ 9.6), 394 (100); HRMS (ESI), m/z 436.8728 M⁺, calcd for Ci₃H₁₂Br₂ClN₂OS 436.8720; HPLC purity 95.24%.

4- (Dibromomethyl) -2- (4-chlorophenyl) -N-methylthiazole- 5 -carboxamide ( 8 ) . Colorless solid (9.5 mg, 20%): mp 165- 167°C. 1H NMR (CDC1₃) δ 7.93 (d, J = 8.4 Hz, 2 H), 7.73 (s, 1 H), 7.43 (d, J = 8.4 Hz, 2 H), 5.98 (brs, 1 H), 3.02 (s, 3 H); ¹³C NMR (CDC1₃) δ 166.56, 160.35, 156.80, 137.65, 130.46, 129.34, 128.18, 123.35, 31.85, 29.59; CIMS m/z (rel intensity) 426/424/422 (MH⁺, 15/71/22); HRMS (ESI), m/z 422.8568 MH⁺, calcd for

C₁₂Hi₀Br₂ClN₂OS 422.8564; HPLC purity 95.13%.

4-(Dibromomethyl)-2-(4-chlorophenyl)-N,N-diethylthiazole-5-carboxamide (9).

Colorless solid (37.2 mg, 86%): mp 63°C. 1H NMR (CDC1₃) δ 7.92 (d, J = 8.4 Hz, 2 H), 7.72 (s, 1 H), 7.44 (d, J = 8.4 Hz, 2 H), 5.94 (brs, 1 H), 3.47 (q, J = 1.2 Hz, 2 H), 1.26 (t, J = 7.2 Hz, 3 H); ¹³C NMR (CDC1₃) δ 166.47, 159.63, 156.67, 137.62, 130.46, 129.33, 128.15, 123.71, 44.21, 41.02, 31.93, 13.55; MS m/z (rel intensity) 491/489/487 (MNa⁺, 8.1/3.3/6.0), 394 (100); HRMS (ESI), m/z 486.8860 MNa⁺, calcd for C₁₅Hi₅Br₂ClN₂OSNa 486.8852; HPLC purity 99.42%.

N-Allyl-4-(dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carboxamide (10).

Colorless solid (8 mg, 18%): mp 135-137°C. 1H NMR (CDC1₃) δ 7.95 (d, J = 8.4 Hz, 2 H) ,

7.73 (s, 1 H), 7.45 (d, J = 8.4 Hz, 2 H), 5.95 (m, 2 H), 5.32 (brs, 1 H), 5.26 (m, 1 H), 4.07 (d, J = 1.2 Hz, 2 H); ¹³C NMR (CDC1₃) δ 166.63, 159.55, 157.03, 137.70, 132.89, 130.45, 129.36,

128.20, 123.21, 117.66, 42.67, 31.79; MS m/z (rel intensity) 452/450/448 (M⁺, 70/100/26);

HRMS (ESI), m/z 447.8652 M⁺, calcd for C₁₄HnBr₂ClN₂OS 447.8647; HPLC purity 98.17%.

4-(Dibromomethyl)-2-(4-chlorophenyl)-N-ethylthiazole-5-carboxamide (11).

Colorless solid (24 mg, 48%): mp 140-141°C. 1H NMR (CDC1₃) δ 7.94 (d, J = 8.4 Hz, 2 H), 7.43 (d, J = 8.4 Hz, 2 H), 6.84 (s, 1 H), 3.48 (q, J = 7.2 Hz, 4 H), 1.24 (t, J = 7.2 Hz, 6 H); ¹³C

NMR (CDC1₃) δ 166.72, 160.65, 153.39, 137.18, 130.66, 129.27, 128.06, 124.45, 43.20, 31.18,

15.81 ; APCIMS m/z (rel intensity) 441/439/437 (MH⁺, 42/100/48); HRMS (CI) m/z 436.8723

MH⁺, calcd for C₁₃H₁₂Br₂ClN₂OS 436.8720; HPLC purity 98.27%. 4-(Dibromomethyl)-2-(4-chlorophenyl)-N-(prop-2-ynyl)thiazole-5-carboxamide (12). White solid (9.6 mg, 20%): mp 177- 178°C. 1H NMR (CDC1₃) δ 7.94 (d, J = 8.7 Hz, 2 H), 7.70 (s, 1 H), 7.46 (d, J = 8.7 Hz, 2 H), 6.01 (brs, 1 H), 4.23 (s, 2 H), 2.3 (s, 1 H); ¹³C NMR (CDC1₃) δ 167.03, 159.38, 157.52, 137.83, 130.37, 129.39, 128.23, 122.37, 72.68, 31.60, 30.00, 29.59; MS m/z (rel intensity) 453/451/499/477 (MH⁺, 92/100/47/41.1); HRMS (ESI), m/z

446.8567 MH⁺, calcd for C₁₄H₁₀Br₂ClN₂OS 446.8569; HPLC purity 100%.

4-(Dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carboxamide (6). Excess saturated ammonium hydroxide solution (30 mL) was added gradually to acid chloride 4 (85 mg, 2 mmol) with continuous stirring at 40-45°C. The suspension was heated at 90°C for 30 min, and the solid was filtered, washed with water several times and purified by crystallization from EtOH to afford the product as a white solid (78.3 mg, 84%): mp 219-220°C. 1H NMR (DMSO) δ 8.00 (d, J = 8.4 Hz, 2 H), 7.80 (s, 1 H), 7.64 (d, J = 8.4 Hz, 2 H); ¹³C NMR

(DMSO) δ 166.35, 158.20, 157.11, 137.24, 131.44, 130.63, 129.21, 125.00, 33.61 ; CIMS m/z (rel intensity) 412/410/408 (MH⁺, 13/100/38); HRMS (ESI) m/z 430.8238 MNa⁺, calcd for CnHvB^ClNaOSNa 430.8227; HPLC purity 95.51%.

Alkyl 4-(Dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carboxylates 13 and 14. The acid chloride 4 (30 mg, 0.07 mmol) was heated under reflux with the alcohol (2 mL) for 6 h. The reaction mixture was allowed to cool, the solvent was evaporated under reduced pressure, and the solid residue was purified by silica gel flash chromatography using hexane- ethyl acetate (9: 1) to afford the products. The physical properties and spectral data are listed below.

Ethyl 4-(Dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carboxylate (13). White solid (20 mg, 81%): mp 185-187°C. 1H NMR (CDC1₃) δ 7.98 (d, J = 8.4 Hz, 2 H), 7.69 (s, 1 H), 7.45 (d, J = 8.4 Hz, 2 H), 4.40 (q, J = 7.2 Hz, 2 H), 1.38 (t, J = 7.2 Hz, 3 H); ¹³C NMR (CDCI₃) δ 169.88, 160.44, 158.68, 137.77, 130.63, 129.33, 128.23, 120.01, 62.29, 31.15, 14.11 ; CIMS m/z (rel intensity) 441/439/437 (MH⁺, 20/67/55), 393 (100); HRMS (EI), m/z 437.8562 MH⁺, calcd for C₁₃HiiBr₂ClN0₂S 437.8560; HPLC purity 96.98%.

Isopropyl 4-(Dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carboxylate (14). White solid (15.3 mg, 49%): mp 176-178°C. 1H NMR (CDC1₃) δ 7.99 (d, J = 8.4 Hz, 2 H), 7.70 (s, 1 H), 7.45 (d, J = 8.4 Hz, 2 H), 5.25 (m, J = 1.2 Hz, 1 H), 1.39 (d, J = 7.2 Hz, 6 H); ¹³C NMR (CDCI₃) δ 169.02, 159.98, 158.47, 139.64, 137.74, 130.69, 129.33, 128.22, 70.43, 46.87, 31.21, 21.75; CIMS m/z (rel intensity) 456/454/452 (MH⁺, 10/47/23), 393 (100); HRMS (EI), m/z 450.8647 M⁺, calcd for C₁₄H₁₂Br₂ClN0₂S 450.8644; HPLC purity 100%.

S-Ethyl 4-(Dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carbothioate (15). The acid chloride 4 (38 mg, 0.09 mmol) was heated under reflux with ethanethiol (0.1 mL, 1.9 mmol) under solvent-free conditions for 4 h. The reaction mixture was allowed to cool. The solvent was taken off under reduced pressure and the solid residue was purified by silica gel flash chromatography using hexane-ethyl acetate (7:3) to afford the product together with a disulfide by-product, which was removed by another silica gel flash chromatography column using hexane-ethyl acetate (97.5:2.5) to yield a white solid (5.5 mg, 10%): mp 90-91°C. 1H NMR (CDC1₃) δ 8.00 (d, J = 8.7 Hz, 2 H), 7.56 (s, 1 H), 7.46 (d, J = 8.7 Hz, 2 H), 3.13 (q, J = 7.5 Hz, 2 H), 1.38 (t, J = 7.5 Hz, 3 H); ¹³C NMR (CDC1₃) δ 181.01, 156.11, 149.58, 144.87,

138.00, 130.89, 129.39, 128.36; APCIMS m/z (rel intensity) 458/456/454 (MH⁺, 7/29/24), 393 (100); HRMS (ESI), m/z 453.8337 MH⁺, calcd for Ci₃HnBr₂ClNOS₂ 453.8332; HPLC purity 99.04%.

S-Methyl 4-(Dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carbothioate (16). The acid chloride 4 (50 mg, 0.12 mmol) was stirred with sodium methanthiol (12 mg, 1.7 mmol) in dry dichlorome thane (10 mL) for 30 min. The solvent was taken off under reduced pressure and the solid residue was partitioned between EtOAc (10 mL) and water (10 mL). The organic layer was separated, dried and evaporated. The yellow precipitate was further purified by crystallization from MeOH to afford the product as pale yellow needles (36 mg, 91%): mp 180-182°C. 1H NMR (CDC1₃) δ 7.99 (d, J = 8.1 Hz, 2 H), 7.56 (s, 1 H), 7.45 (d, J = 8.1 Hz, 2 H), 2.55 (s, 1 H); ¹³C NMR (CDC1₃) δ 183.20, 169.11, 156.20, 138.11, 130.46, 129.45, 128.44, 127.34, 31.59, 12.97; APCIMS m/z (rel intensity) 444/442/440 (MH⁺, 19/41/33), 395 (MH⁺ - CH₃, 100); HRMS (ESI), m/z 439.8185 MH⁺, calcd for Ci₂H₉Br₂ClNOS₂ 439.8175; HPLC purity 100%.

l-(2-(4-Chlorophenyl)-4-methylthiazol-5-yl)ethanone (19). 4-

Chlorothiobenzamide (18, 1.71 g, 10 mmol) and 3-chloropentane-2,4-dione (1.604 g, 12 mmol) were added to absolute ethanol (50 mL). The reaction mixture was heated at reflux for 24 h. After removal of solvent under reduced pressure, the residue was crystallized from ethanol- methanol-ethyl acetate (10:85:5) to provide the compound as a white needles (1.852 g, 73%): mp 114- 115°C. 1H NMR (CDC1₃) δ 7.91 (d, J = 8.7 Hz, 2 H), 7.44 (d, J = 8.7 Hz, 2 H), 2.77 (s, 3 H), 2.57 (s, 3 H); ¹³C NMR (CDC1₃) δ 190.33, 167.86, 159.44, 137.16, 131.17, 129.24, 127.97, 30.67, 18.34; EIMS m/z (rel intensity) 253/251 (MH⁺, 26/70), 236 (M⁺ - CH₃, 100); HRMS (EI), m/z 251.0172 M⁺, calcd for C₁₂H₁₀C1NOS 251.0173; HPLC purity 98.98%. l-(4-(Dibromomethyl)-2-(4-chlorophenyl)thiazol-5-yl)ethanone (20). Compound 19 (251 mg, 1 mmol) and NBS (358 mg, 2 mmol) were added to CC1₄ (5 mL). The reaction mixture was irradiated for 5 min frequently (15 min intervals) by an ultraviolet sunlamp (GE, 215 W) and heated at reflux for 12 h. After removal of solvent under reduced pressure, the residual NBS was removed by adding saturated aq NaOH (3 mL), and the mixture was filtered and washed with distilled water. The collected brown solid was purified by silica gel chromatography using ethyl acetate-hexanes (1 : 1) to provide the compound as a white solid (204 mg, 50%): mp 193- 195°C. 1H NMR (CDC1₃) δ 8.00 (d, J = 8.7 Hz, 2 H), 7.67 (s, 1 H), 7.47 (d, J = 8.7 Hz, 2 H), 2.59 (s, 3 H); ¹³C NMR (CDC1₃) δ 189.56, 168.67, 160.61, 158.02, 138.03, 130.40, 129.41, 128.34, 32.00, 31.28; CIMS m/z (rel intensity) 412/410/408 (MH⁺, 30/78/32); HRMS (ESI), m/z 406.8378 MH⁺, calcd for Ci₂H₈Br₂ClNOS 406.8382; HPLC purity 95.13%.

(£)- 1 - (4- (Dibromomethyl) -2- (4-chlorophenyl)thiazol- 5 -yl)- 3 - (dimethylamino)prop-2-en-l-one (21). A mixture of thiazole derivative 20 (1 mmol) and DMF- DMA (0.357 mL, 3 mmol) was taken in dry toluene (20 mL) and the mixture was heated at reflux for 24 h and then left to cool at room temperature. The solvent was evaporated under reduced pressure. The reddish-yellow precipitated product was washed with petroleum ether (60/80°C) and dried. Recrystallization from benzene afforded the compound as an orange solid (303 mg, 66%): mp 148- 149°C. 1H NMR (CDC1₃) δ 7.96 (d, J = 8.3 Hz, 2 H), 7.93, (s, 1 H), 7.76 (d, J = 12 Hz, 2 H), 7.40 (d, J = 8.3 Hz, 2 H), 5.34 (d, J = 12 Hz, 2 H), 3.17 (s, 3 H), 2.93 (s, 3 H); ¹³C NMR (CDC1₃) δ 178.70, 166.27, 154.92, 137.04, 131.26, 131.07, 130.40, 129.16, 128.09, 127.63, 94.83, 45.39, 37.52, 33.65; ESIMS m/z (rel intensity) 467/465/563 (MH⁺, 65/100/42); HRMS (ESI), m/z 462.8880 MH⁺, calcd for C₁₅Hi₄Br₂ClN₂OS 462.8877; HPLC purity 100%.

Preparation of Hydroxyalkyl and Carbohydrate Amide Derivatives. General

Procedure. Primary amine (1 mmol) was added to acid chloride 4 (41 mg, 1 mmol) in dry dichloromethane (2 mL). The reaction mixture was stirred at room temperature for 0.5-1 h. The solvent was evaporated under reduced pressure. The solid residue was purified by

crystallization from methanol. The physical and spectral data of the obtained compounds are listed below.

4- (Dibromomethyl) -2- (4-chlorophenyl) -N- (2-hydroxyethyl) thiazole- 5 - carboxamide (22). White solid (11 mg, 27%): mp 132- 133°C. 1H NMR (CDC1₃) δ 7.93 (d, J = 8.4 Hz, 2 H), 7.72 (s, 1 H), 7.45 (d, J = 8.4 Hz, 2 H), 6.45 (brs, 1 H), 3.87 (t, J = 7 Hz, 2 H), 3.64 (t, J = 7 Hz, 2 H), 2.2 (brs, 1 H); ^1JC NMR (CDC1₃) δ 166.89, 165.66, 157.10, 137.77, 130.48, 129.42, 128.26, 123.27, 61.51, 42.58, 31.88; CIMS m/z (rel intensity) 457/455/453 (MH⁺, 65/79/17); HRMS (ESI), m/z 451.8594 M⁺, calcd for Ci₃HnBr₂ClN₂OS 451.8596; HPLC purity 96.21%.

(_lS')-4-(Dibromomethyl)-2-(4-chlorophenyl)-N-(2,3-dihydroxypropyl)thiazole-5- carboxamide (23). White solid (13 mg, 12%): 144-146°C. 1H NMR (CD₃OD) δ 8.03 (d, J = 8.7 Hz, 2 H), 7.80 (s, 1 H), 7.53 (d, J = 7.8 Hz, 2 H), 3.54 (m, J = 4.9 Hz, 1 H), 3.29 (dd, J = 1.5 and 4.9 Hz, 2 H), 3.21 (dd, J = 1.5 and 4.9 Hz, 2 H); ¹³C NMR (CD₃OD) δ 166.28, 159.07, 158.18, 143.36, 138.65, 132.21, 130.59, 129.39, 71.70, 65.23, 44.28, 32.71 ; ESIMS m/z (rel intensity) 485/483/481 (MH⁺, 17 /46/41); HPLC purity 99.56%.

4-(Dibromomethyl)-2-(4-chlorophenyl)-N-(ribityl)thiazole-5-carboxamide (24). White solid (11.9 mg, 86%): 217-219°C. 1H NMR (CD₃OD) δ 8.03 (d, J = 7.5 Hz, 2 H), 7.77 (s, 1 H), 7.52 (d, J = 7.8 Hz, 2 H), 2.98 (s, 3 H), 2.85 (s, 3 H), 2.80 (s, 1 H); ¹³C NMR

(CD₃OD) δ 170.96, 164.87, 159.65, 138.83, 132.26, 130.59, 129.47, 123.25, 74.10, 74.04, 69.97, 64.58, 36.98, 31.90; ESIMS m/z (rel intensity) 548/546/544/542 (MH⁺, 17/81/31/53); HRMS (ESI), m/z 542.8996 MH⁺, calcd for Ci₆H₁₈Br₂ClN₂0₅S 542.8986; HPLC purity 98.98%.

4-(Dibromomethyl)-2-(4-chlorophenyl)-N-(D-glucosyl)thiazole-5-carboxamide (25). White solid (10 mg, 18%): 190- 191°C. 1H NMR (CD₃OD) δ 8.24 (d, J = 7.8 Hz, 2 H), 7.82 (s, 1 H), 7.75 (d, J = 7.8 Hz, 2 H), 5.24 (s, J = 3.4 Hz, 1 H), 4.04 (dd, J = 3.5 and 10 Hz, 1 H), 3.89-3.70 (m, 5 H); ¹³C NMR (CD₃OD) δ 169.07, 163.20, 154.42, 143.82, 136.25, 132.24, 130.56, 129.35, 91.10, 73.34, 72.19, 62.69, 62.19, 56.76. 31.93; ESIMS m/z (rel intensity) 597/595/593 (MNa⁺, 87/100/55); HRMS (ESI), m/z 592.8757 MNa⁺, calcd for

Ci₇H₁₇Br₂ClN₂0₆SNa 592.8755; HPLC purity 98.59%.

Ethyl 2-Chloro-3-(furan-2-yl)-3-oxopropanoate (27c). Sulfuryl chloride (3.3 mmol) was added drop-wise to a stirred solution of diketo compounds 26c (3 mmol) in dry methylene chloride (10 mL). The mixture was vigorously stirred for 1 h. The solvent was

20

evaporated. The product was collected as a colorless to faint- yellow oil, and purified by column chromatography, using 6:4 hexane-ethyl acetate. Yellow oil (621 mg, 96%). 1H NMR (CDC1₃) δ 8.22 (s, 1 H), 7.47 (s, 1 H), 6.82 (s, 1 H), 5.20 (s, 1 H), 4.85 (q, J = 7.2 Hz, 2 H), 1.26 (t, J = 7.2 Hz, 3 H); ¹³C NMR (CDC1₃) δ 182.80, 164.86, 149.09, 144.38, 109.02, 63.25, 59.75, 13.97; ESIMS m/z (rel intensity) 218/216 (MH⁺, 23/100); HRMS (ESI), m/z 216.0184 MH⁺, calcd for C₉H₉C10₄ 216.0189; HPLC purity 96.81%. Preparation of Alkyl 2-(4-Chlorophenyl)-4-alkylthiazole-5-carboxylates (28- 31). General Procedure. 4-Chloro-thiobenzamide (171 mg, 1 mmol) and a-chlorodiketo derivatives 27a-d (1.2 mmol) were added to absolute ethanol (15 mL). The reaction mixture was heated to reflux for 24 h. After removal of solvent under reduced pressure, the residue was purified by silica gel chromatography (hexanes-ethyl acetate 7:3) to provide the compounds. The physical and spectral data of products are listed below.

Methyl 2-(4-Chlorophenyl)-4-ethylthiazole-5-carboxylate (28). White solid (277.6 mg, 98%): mp 86-87°C. 1H NMR (CDC1₃) δ 7.93 (d, J = 8.4 Hz, 2 H), 7.20 (d, J = 8.4 Hz, 2 H), 3.96 (q, J = 7.5 Hz, 2 H), 3.89 (s, 3 H), 1.36 (t, J = 7.5 Hz, 3 H); ¹³C NMR (CDC1₃) δ 172.21, 166.97, 160.32, 136.90, 131.44, 129.17, 127.94, 120.00, 52.10, 24.31, 13.52; ESIMS m/z (rel intensity) 284/282 (MH⁺, 35/100); HRMS (ESI), m/z 282.0360 MH⁺, calcd for Ci₃H₁₃ClN0₂S 282.0350; HPLC purity 97.80%.

Methyl 2-(4-Chlorophenyl)-4-isopropylthiazole-5-carboxylate (29). White solid (186 mg, 63%): mp 70-71°C. 1H NMR (CDC1₃) δ 7.92 (d, J = 8.4 Hz, 2 H), 7.39 (d, J = 8.4 Hz, 2 H), 3.98 (m, 1 H), 3.88 (s, 1 H), 1.345 (d, J = 6.9 Hz, 6 H); ¹³C NMR (CDC1₃) δ 171.00,

168.55, 162.20, 138.09, 133.67, 129.09, 127.95, 120.10, 52.04, 29.10, 21.99; ESIMS m/z (rel intensity) 298/296 (MH⁺, 34/100); HRMS (ESI), m/z 296.0509 MH⁺, calcd for C₁₄H₁₅C1N0₂S 296.0506; HPLC purity 97.78%.

Methyl 4-ieri-Butyl-2-(4-chlorophenyl)thiazole-5-carboxylate (30). White solid (270 mg, 87%): 105- 106°C. 1H NMR (CDC1₃) δ 7.91 (d, J = 8.4 Hz, 2 H), 7.41 (d, J = 8.4 Hz, 2 H), 3.87 (s, 3 H), 1.53 (s, 9 H); ¹³C NMR (CDC1₃) δ 171.62, 165.84, 162.00, 136.61, 131.63, 129.10, 127.82, 121.34, 52.27, 36.61, 29.36; ESIMS m/z (rel intensity) 312/310 (MH⁺, 27/100); HRMS (ESI), m/z 310.0672 MH⁺, calcd for C₁₅Hi₇ClN0₂S 310.0663; HPLC purity 95.63%.

Ethyl 2-(4-Chlorophenyl)-4-(furan-2-yl)thiazole-5-carboxylate (31). 4-Chloro- thiobenzamide (256.5 mg, 1.5 mmol) and a-chlorodiketo derivative 27c (4.33 mg, 2 mmol) were added to absolute ethanol (15 mL). The reaction mixture was heated at reflux for 24 h. After removal of solvent under reduced pressure, the residue was purified by silica gel chromatography (hexanes-ethyl acetate 7:3, then 9: 1) to provide the compound as a white solid (481 mg, 96%): mp 82-83°C. 1H NMR (CDC1₃) δ 8.59 (s, 1 H), 7.98 (d, J = 8.4 Hz, 2 H), 7.83 (d, J = 8.4 Hz, 2 H), 7.44 (s, 1 H), 7.23 (s, 1 H), 2.47 (q, J = 7.2 Hz, 2 H), 1.40 (t, J = 7.2 Hz, 3 H); ESIMS m/z (rel intensity) 336/334 (MH⁺, 19/100); HRMS (ESI), m/z 334.0309 MH⁺, calcd for C₁₆Hi₃ClN0₃S 334.0229; HPLC purity 95.33%.

2-(4-Chlorophenyl)-4-(methoxymethyl)-N-methylthiazole-5-carboxamide (33). NaOH (4.00 g, 100 mmol) was added to a solution of methyl carboxylate 32 (6.237 g, 21 mmol) in ethanol (40 mL) and water (5 mL). The reaction mixture was heated under reflux for 5 h, and then allowed to cool to room temperature. The reaction mixture was filtered and the pH value of the liquid phase was adjusted to 2 with hydrochloride acid. The solid was filtered and dried to provide an off-white solid (4.980 g, 84%). The crude obtained solid material (4.88 g, 17.2 mmol) was heated under reflux with thionyl chloride (25 mL) for 6 h. The solvent was evaporated under reduced pressure. The brown residue was collected and purified by silica gel flash chromatography, using hexane-ethyl acetate (7:3), to yield the corresponding acid chloride as a white solid (2.507 g, 96%). Methylamine hydrochloride (88 mg, 1.3 mmol) and potassium carbonate (27 mg, 0.5 mmol) were dissolved in water (10 mL) and then the corresponding acid chloride (380 mg, 1.26 mmol) was added after 5 min. The reaction mixture was stirred at room temperature for 1 h. The white flocculant solid was collected by filtration and washed with HC1 (0.1 M, 5 mL) and then water (3 x 10 mL). The white solid was further purified by crystallization from EtOAc to yield a white solid (339.4 mg, 91%): mp 113-114°C. 1H NMR (CDC1₃) δ 8.07 (brs, 1 H), 7.86 (d, J = 8.7 Hz, 2 H), 7.41 (d, J = 8.7 Hz, 2 H), 4.78 (s, 2 H), 3.46 (s, 3 H), 2.99 (d, J = 4.8 Hz, 3 H); ¹³C NMR (CDC1₃) δ 166.05, 161.56, 151.46, 136.78, 135.11, 131.33, 129.25, 127.80, 69.32, 58.04, 26.90; ESIMS m/z (rel intensity) 298/297 (MH⁺, 38/100); HRMS (ESI), m/z 297.0464 MH⁺, calcd for C₁₃Hi₄ClN₂0₂S 297.0459; HPLC purity 95.00%.

2-(4-Chlorophenyl)-4-formyl-N-methylthiazole-5-carboxamide (34). Methyl ether 33 (300 mg, 1 mmol) and NBS (178 mg, 1 mmol) were added to CC1₄ (15 mL). The reaction mixture was heated at reflux for 1 h and was illuminated four times by a 60-watt bulb for 5 min with time intervals of 15 min. The solvent was removed under reduced pressure. The residue was partitioned between EtOAc (10 mL) and NaOH (0.1 M NaOH, 5 mL). The organic layer was separated, dried over anhydrous MgS0₄, and removed under reduced pressure. The semisolid residue was purified by silica gel flash chromatography using hexane-ethyl acetate (3: 1) to afford the product as a white solid (56%): 231-232°C. 1H NMR (CDC1₃) δ 10.15 (s, 1 H), 9.78 (brs, 1 H), 7.93 (d, J = 8.4 Hz, 2 H), 7.46 (d, J = 8.4 Hz, 2 H), 3.04 (d, J = 4.8 Hz, 3 H); ¹³C NMR (CDC1₃) δ 188.92, 168.13, 159.29, 147.60, 145.36, 137.68, 130.49, 129.53, 127.96, 29.65; MS m/z (rel intensity) 283/281 (MH⁺, 51/100); HRMS (ESI), m/z 281.0157 MH⁺, calcd for C₁₂Hi₀ClN₂O₂S 281.0146; HPLC purity 95.13%.

Methyl 2-(4-Chlorophenyl)-4-cyanothiazole-5-carboxylate (36). Method A: (22. Suzuki, H.; Nakaya, C. A Convenient One-Step Method of Converting Electron-Rich Aromatic Aldehydes into Nitriles. Synthesis 1992, 641-642.) To a stirred solution of A1C1₃ (40 mg. 0.3 mmol) in THF (3 mL) was added NaN₃ (61 mg, 0.94 mmol) followed by aldehyde 35 (44 mg, 0.15 mmol). The mixture was heated to gentle reflux. After 12 h the reaction mixture was diluted with 10% HC1 (3 mL) and THF was removed under reduced pressure. The organic layer was extracted with ethyl acetate (3 x 5 mL), dried and evaporated. The residue was purified by column chromatography on silica gel using a mixture of hexane-ethyl acetate (4: 1) to obtain the product (9 mg, 21%). Method B(23. Jiun-Jie, S.; Jim-Min, F., Direct Conversion of Aldehydes to Amides, Tetrazoles, and Triazines in Aqueous Media by One-Pot Tandem Reactions. J. Org. Chem. 2003, 68, 1158-1160.): A solution of aldehyde 35 (20 mg, 0.07 mmol) and iodine (12.7 mg, 0.1 mmol) in ammonia solution (3 mL of 28% solution) and THF (0.5 mL) was stirred at room temperature for 1 h (until the solution became colorless). Then the reaction mixture was charged with aqueous Na₂S₂0₃ (5% solution), followed by extraction with ethyl acetate (2 x 5 mL) to give the crude nitrile 36, which was purified by column chromatography on silica gel using a mixture of hexane-ethyl acetate (7:3) to yield a white solid (18.5 mg, 99%): mp 142- 143°C. 1H NMR (CDC1₃) δ 7.92 (d, J = 8.7 Hz, 2 H), 7.48 (d, J = 8.7 Hz, 2 H), 4.02 (s, 3 H); ¹³C NMR (CDC1₃) δ 171.24, 159.01, 138.63, 133.28, 129.65, 129.27, 128.23, 112.49, 53.43; CIMS m/z (rel intensity) 280/278 (M⁺, 30/100); HRMS (CI), m/z 278.9992 MH⁺, calcd for C₁₂H₉C1N₂0₂S 278.9989; HPLC purity 100%.

Methyl 4-(Dichloromethyl)-2-(4-chlorophenyl)thiazole-5-carboxylate (37). ( 24. Wolfson, A.; Shokin, O.; Tavor, D. Acid Catalyzes the Synthesis of Aromatic Gem-Dihalides from Their Corresponding Aromatic Aldehydes. J. Mol. Cat. A: Chem. 2005, 226, 69-76.) The aldehyde derivative 35 (25 mg, 0.09 mmol), acetyl chloride (13

0.178 mmol) and anhydrous aluminum chloride (3.8 mg, 0.028 mmol) were added to dichlorobenzene (3 mL). The reaction mixture was heated at reflux for 24 h. The solvent was taken off under reduced pressure and the orange oily residue was purified by silica gel flash chromatography using hexane-ethyl acetate (7:3) to yield 37 as an off-white solid (29 mg, 99%): mp 133°C. 1H NMR (CDCI₃) δ 8.27 (s, 3 H), 7.98 (d, J = 8.7 Hz, 2 H), 7.46 (d, J = 8.7 Hz, 2 H), 3.95 (s, 3 H); ¹³C NMR (CDCI₃) δ 168.07, 160.64, 155.78, 137.79, 130.66, 129.33, 128.30, 124.30, 75.49, 52.96; ESIMS m/z (rel intensity) 304/302/300 (MH⁺- HC1, 25/62.8/100); HRMS (ESI), m/z 299.9650 (M⁺ - HC1), calcd for C₁₂H₇C1₂N0₂S 299.9647; HPLC purity 99.78%.

Methyl 4-(Bromomethyl)-2-(4-chlorophenyl)thiazole-5-carboxylate (38).

Methyl ester 2 (1.045 g, 3.9 mmol), NBS (767 mg, 4.3 mmol) and benzoylperoxide (10 mg) were added to CC1₄ (25 mL). The reaction mixture was heated at reflux for 24 h. After removal of solvent under reduced pressure, the residual NBS was removed by adding saturated aq NaOH (20 mL), filtering and washing with distilled water. The collected yellowish- white precipitate was purified by silica gel chromatography (ethyl acetate-hexanes 1:4) to provide the compound as a white solid (676 mg, 50%): mp 151-152°C.¹H NMR (CDC1₃) δ 7.92 (d, J = 8.7 Hz, 2 H), 7.43 (d, J = 8.7 Hz, 2 H), 4.97 (s, 2 H), 3.93 (s, 3 H); ¹³C NMR (CDC1₃) δ 169.45, 161.37, 158.71, 137.55, 130.86, 129.36, 128.12, 124.05, 52.68, 24.80; ESIMS m/z (rel intensity) 349/347/345 (MH⁺, 11/38/29); HRMS (ESI), m/z 344.9229 M⁺, calcd for

C₁₂H₉BrClN0₂S 344.9226; HPLC purity 100%.

Methyl 2-(4-Chlorophenyl)-4-[(methylsulfonyl)methyl]thiazole-5-carboxylate (39). Compound 38 (46 mg, 0.133 mmol) and sodium methylsulfinate (24 mg, 0.26 mmol) were added to absolute ethanol (3 mL). The reaction mixture was heated at reflux for 12 h. After removal of solvent under reduced pressure, the off-white solid was partitioned between EtOAc (5 mL) and water (10 mL). The organic layer was separated, dried over MgS0₄ and evaporated under reduced pressure. The collected solid material was purified by crystallization from MeOH-EtOAc to provide the product as a white solid (38.1 mg, 83%): mp 178-179°C. 1H NMR (CDC1₃) δ 7.89 (d, J = 8.4 Hz, 2 H), 7.44 (d, J = 8.4 Hz, 2 H), 5.01 (s, 2 H), 3.93 (s, 3 H), 3.09 (s, 3 H); ¹³C NMR (CDC1₃) δ 169.80, 161.41, 150.42, 137.83, 130.62, 129.48, 128.06, 126.68, 55.24, 52.88, 41.33; CIMS m/z (rel intensity) 347/345 (M⁺, 4/19), 268/266 (M⁺ - CH₃S0₂, 39/100); HRMS (CI), m/z 344.9902 M⁺, calcd for Ci₃H₁₂ClN0₄S 344.9896; HPLC purity 96.02%.

BIOASSAY METHODS

BHK cells. BHK-15 cells obtained from the American Type Culture Collection (ATCC, Rockville, MD) were maintained in MEM (Invitrogen, Carlsbad, CA) containing 10% FBS. Cells were grown in incubators at 37 °C in the presence of 5% C0₂.

YFV-IRES-Luc. A fire-fly luciferase reporter gene was inserted into pYF23, a derivative of pACNR which is the full-length cDNA clone of YFV 17D, to construct YFV- IRES-Luc, a luciferase-reporting full-length virus. To facilitate this construction, an Nsil restriction site was introduced at the beginning of the 3'NTR immediately following the UGA termination codon of NS5 in pYF23 using standard overlapping PCR mutagenesis. To construct YFV-IRES-Luc, an IRES-FF.Luc (EMCV IRES-fire fly luciferase) cassette was amplified by PCR from YFRP-IRES-Luc, a YFV replicon, and inserted into the Nsil restriction site. (25. Jones, C.T.; Patkar, C. G.; Kuhn, R. J. Construction and Application of Yellow Fever Virus Replicons. Virology 2005, 331, 247-259.) Generation of YFV-IRES-Luc Virus. In vitro transcribed YFV-IRES-Luc RNA was transfected into BHK-15 cells using Lipofectamine (Invitrogen, Carlsbad,CA). At 4 days post-transfection, the resulting YFV-IRES-Luc virus was harvested and the titer of the virus determined by a standard plaque assay. The infectivity of the virus could be assayed directly as a measure of the luciferase amounts produced in infected cells over a period of time.

Inhibition of YFV-IRES-Luc Virus Growth. BHK cells were plated in a 96-well plate and grown at 37°C. At confluency, cells were infected with YF-IRES-Luc virus at a multiplicity of infection (MOI) of 0.1. A low MOI was utilized to ensure that fewer cells were infected so that the spread of released virus could be monitored. Cells were then overlaid with culture media containing serial dilutions of compounds at concentrations below the GI₅₀ values. Controls included uninfected cells, infected cells, and DMSO-treated infected cells. Cells were incubated at 37 °C, 5% C0₂ for -36 h, lysed using 50 of cell culture lysis buffer (Promega Inc., Madison, WI), and 10 of cell extracts placed into a 96-well opaque plate. Luciferase activity was determined from the luminescence generated with fire-fly luciferase substrate (Promega Inc., Madison, WI). Luminescense was measured in a 96-well-plate luminometer, LMax II (Molecular Devices, Sunnyvale, CA). A reduction in luciferase activity indicates inhibition of YFV-IRES-Luc virus growth. The luciferase luminescence as a function of compound concentration was analyzed by non-linear regression analysis using

GraphPadPrizm to estimate the IC₅₀ of each compound. The IC₅₀ was defined as the concentration of the compound to cause 50% reduction of luciferase activity in infected cells as compared to the DMSO-treated cells.

Cell Viability Assay. BHK cells were plated in a 96-well plate and grown at 37°C. At confluency, cells were overlaid with culture media containing serial dilutions of compounds (compound stocks were generated by dissolving compounds in DMSO). Untreated and DMSO-treated cells served as positive controls. Cells were then incubated at 37°C, 5% C0₂ for -36 h. At -36 h post-treatment, media on cells was replaced with fresh media to remove the compounds. Then 10 μΐ_^ of XTT-substrate from the Quick Cell Proliferation Kit (Biovision Inc., CA) was added to each well. Cells were incubated at 37 °C for a further 2 h. Plates were then removed and OD450 measured using a 96-well plate reader (Molecular Devices, Sunnyvale, CA). The OD450 value for cells treated with a compound was compared to that obtained from cells treated with 1% DMSO and the GI₅₀ for each compound was calculated. MOLECULAR MODELING

Molecule Construction and Energy Optimization. Compounds 1, 23-25, and 39 were built with Sybyl 7.1 software and minimized to 0.01 kcal/mol by the Powell method, using Gasteiger-Hiickel charges and the Tripos force field. To save calculation time, solvents were not taken into account, and instead the dielectric constant was set to a value of 4 to mimic the aqueous environment. The minimized molecules underwent 10 rounds of simulated annealing to search for the optimized conformation. During the simulation process, the starting conformation in each round was heated to 700 K within 1000 fs and then cooled to 200 K in the same period. Conformations were recorded at each temperature level (700 K and 200 K). The conformers located at the starting point at the each round of simulation were selected for the further energy refinement using the same parameter set as the ones in molecular construction. The minimized conformer with the lowest energy was selected as the optimized conformation of the molecule which was docked into the β-OG binding pocket of the yellow fever virus E-protein (PDB ID: 10KE).

Docking Simulation. The energy-optimized compounds were docked into the β-

OG binding domain in the E-protein of the dengue virus after removal of the w-octyl-β-Ο- glucoside (β-OG). The parameters were set as the default values for GOLD. The maximum distance between hydrogen bond donors and acceptors for hydrogen bonding was set to 3.5 A. After docking, the first pose conformation of compounds 1, 23-25, and 39 were merged into the ligand-free protein. The new ligand-protein complex was subsequently subjected to energy minimization using the Amber force field with Amber charges. During the energy

minimization, the structure of the compounds of interest and only chain A of the viral E protein were allowed to move. Chain B was kept frozen. The energy minimization was performed using the Powell method with a 0.05 kcal/(mol A) energy gradient convergence criterion and a distance dependent dielectric function.

In Vitro Hydrolytic Stability Assay Utilizing Rat Plasma. Compounds 1 and 16 were tested for their hydrolytic stability in solutions of reconstituted rat plasma. Compounds 1 and 16 (15-5 μιηοΐ) and 7 μιηοΐ of 4-bromopyrazole as an internal standard were dissolved in DMSO (1.0 mL). This solution was filtered through a 0.45 μΜ filter (Millex-HN). Lyophilized rat plasma (1.0 mL) (LOT# 048K7420, Sigma Chemical Co., St. Louis, Mo) was reconstituted with water of HPLC (1.0 mL). The plasma solution was incubated at 37 °C for 15 min and was then diluted with 0.01 M saline (0.250 mL) to afford an 80% plasma solution. The plasma solution was incubated again at 37 °C for an additional 5 min. An aliquot of the compounds 1 and 16 in DMSO (100 μί) were added to the rat plasma (0.75 mL) and the mixture was incubated at 37 °C throughout the course of the experiment. Aliquots (10 μί) of the compound- plasma mixture were collected at various time intervals and diluted with methanol (90 μί) to precipitate any proteins present. The aliquots were mixed and centrifuged at 10,000 rpm for 5- 10 min to pellet the precipitated proteins. After centrifugation, the supernatants (20 μί) of the aliquots were analyzed by HPLC to determine the residual amount of tested compounds present in the sample. The aliquot supernatants were analyzed using a Waters binary HPLC system (Model 1525, 10 μΐ_^ injection loop) and a Waters dual wavelength absorbance UV detector (Model 2487) set for 254 nM. Data were collected and processed using the Breeze software (version 3.3) on a Dell Optiplex GX280 personal computer. The mobile phase consisted of 85: 15 (v/v) methanol/water and the Sunrise^® HPLC column (4.6 mm x 150 mm) was packed with C18 Silica from Waters. The column was maintained at room temperature during the analyses. The half-life of 1 and 16 were calculated from regression curves fitted to plots of the compound concentration versus time.

Scheme 1^a

aReagents and conditions: (a, a') NBS, UV irradiation, heat to reflux for 24 h, CCI₄, 87% for a and 63% for a'; (b, b') i, 80% methanol, NaOH, heat to reflux for 2 h, ii, SOCI₂, heat to reflux for 2 h, 95% for b and 53% for b'. (c) CH₂CI₂, alkylamine, 23 °C, 2-1 0 min, 10-86%, or NH₃ solution, 40 °C, 30 min, 84%; (d) absolute ethanol or 2- propanol, Et₃N, heat to reflux for 6 h, 49-81 %; (e) ethanethiol heat to reflux for 4 h, or MeONa/CH₂CI₂, 23 °C, 0.5 h, 73-91 %. Scheme 2^a

20 21 aReagents and conditions: (a) absolute ethanol, heat to reflux for 24 h, 73%; (b) NBS, UV irradiation, heat to reflux for 12 h, CCI₄, 50%; (c) DMF-DMA, dry toluene, heat to reflux to 24 h, 66%.

Scheme 3^a

22, R= C₂H₄OH

OH

aReagents and conditions: (a) DMF, 23 °C, 0.5-1 h, 12-86%.

Scheme 4^ε

27d, 28 R¹ = CH₂CH₃, R² = CH₃

26a, 27a, 29 R¹ = CH(CH₃)₂, R² = CH₃

1 = ² = CH₃

aReagents and conditions: (a) CH₂CI₂, S0₂CI₂, 23 °C, 2 h, 90-96%; (b) absolute ethanol, heat to reflux for 24 h, 63-96%.

Scheme 5^!

32 33 34 ^aReagents and conditions: (a) i, 80% methanol, NaOH, heat to reflux for 2 h, 83%, ii, SOCI₂, heat to reflux for 2 h, 96%, iii, MeNH₂.HCI, K₂C0₃, CH₂CI₂, 23 oC, 1 h, 91 %; (b) NBS (1 equiv), UV irradiation, heat to reflux for 2 h, CCI₄, 63%. Scheme 6^a

^aReagents and conditions: (a) anhydrous AICI₃, THF, NaN₃, heat to gentle reflux for 24 h, 28%; (b) l₂, NH₃ solution, THF, 23 °C, 1 h, 99%; (c) AcCI (2 equiv.), anhydrous AICI₃, dichlorobenzene, heat to reflux for 24 h, 21 %.

Scheme 7^a

^aReagents and conditions: (a) NBS (1 .1 equiv), Bz₂0₂, CCI , heat to gentle reflux for 24 h, 50%; (b) MeS0₂Na, absolute ethanol, heat to reflux for 12 h, 83%. Chart 1. Polar Dibromomethyl Replacement.

Table 1. Antiviral Activities and Cytotoxicities of Compounds vs. Yellow Fever Virus.

Comp. % GL^ EC₅₀ ^C

Inhibition^a (uM) (uM)

5 93.6 81.4 ± 39.1 1.7 ± 0.6

6 99.8 99.7 ± 37.0 1.7 ± 0.5

7 93.2 162.9 ± 23.3 20.0 ± 2.5

8 99.7 74.6 ± 5.1 1.8 ± 0.7

9 99.8 63.5 ± 14.9 13.7 ± 0.6

10 99.9 40.8 ± 0.9 1.6 ± 0.4

11 99.9 33.3 ± 5.4 2.7 ± 0.8

12 99.7 23.9 ± 3.9 1.7 ± 0.2

13 98.1 94.6 ± 28.9 8.7 ± 2.9

14 84.4 372.3 ± 22.3 19.9 ± 2.5

15 99.7 81.4 ± 39.1 1.6 ± 0.1

16 99.6 368.7± 7.5 1.4 ± 0.1

20 99.9 83.5 ± 10.9 1.3 ± 0.5

21 99.8 38.2 ± 9.8 11.4 ± 6.4

22 99.8 40.8 ± 0.9 2.9 ± 0.5

23 99.9 158.0 ± 20.4 1.1 ± 0.1

24 53.2 NA NA

25 43.4 NA NA

28 -56.7 NA NA

29 14.7 49.6 ± 3.6 58.7 ± 17.0 30 20.9 NA NA

31 50.3 465 ± 40 311.0 ± 25.0

158.3 ±

32 38.1 387.9 ± 25.0

157.6

33 99.7 50.8 ± 4.2 2.9 ± 0.5

34 37.5 NA NA

35 99.9 36.4± 2.1 42.8 ± 17.4

36 7.8 NA NA

37 99.9 34.1 ± 1.4 52.8 ± 18.1

38 99.9 74.6 ± 5.1 1.6 ± 0.5

39 -74.7 NA NA

40 30.1 NA NA

41 11.3 NA NA

42 5.5 NA NA

43 74.0 99.7 ± 37.0 51.0 ± 18.0

44 99.6 162.9 ± 23.3 26.5 ± 1.8

45 1.5 NA NA

Note: Measured as a reduction in luciferase activity of BHK cells infected with YF-IRES-Luc at 50 μΜ in comparison to the control; ^bThe GI₅₀ is the concentration of the compound causing a 50% growth inhibition of uninfected BHK cells. ^cThe EC₅₀ is the concentration of the compound resulting in a 50% inhibition in virus production. ^dNA indicates that the value was not determined.

Claims

WHAT IS CLAIMED IS:

1. A compound of the formula

or a pharmaceutically acceptable salt thereof, wherein

R is CHO, carboxylic acid or derivative thereof, optionally substituted alkyl, or optionally substituted heteroaryl;

Z is CHO or a derivative thereof, a ketone or derivative thereof, or a derivative of a carboxylic acid; where Z is not CC^Me; and where Z is not an ester or 3,4- dichlorobenzylamide when R is methyl; and

Ar is optionally substituted aryl or optionally substituted heteroaryl.

2. The compound of claim 1 wherein Ar is substituted phenyl.

3. The compound of claim 1 wherein Ar is phenyl substituted with one or more substituents, each independently selected from halo, hydroxy, amino, thio, carboxylate and derivatives thereof, sulfinyl and derivatives thereof, sulfonyl and derivatives thereof, phosphinyl and derivatives thereof, and phosphonyl and derivatives thereof, and alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heteroalkyl, heteroalkenyl, cycloheteroalkyl,

cycloheteroalkenyl, aryl, heteroaryl, arylalkyl, and heteroarylalkyl, each of which is optionally substituted; where 2 of said substituents are optionally taken together to form heterocycle.

4. The compound of any one of claims 1 to 3 wherein R is alkyl.

5. The compound of any one of claims 1 to 3 wherein R is branched alkyl.

6. The compound of any one of claims 1 to 3 wherein R is substituted alkyl.

7. The compound of any one of claims 1 to 3 wherein R is haloalkyl.

8. The compound of any one of claims 1 to 3 wherein R is dibromomethyl.

9. The compound of any one of claims 1 to 3 wherein R is dichloromethyl.

10. The compound of any one of claims 1 to 3 wherein R is alkoxyalkyl.

11. The compound of any one of claims 1 to 3 wherein R is alkylsulfonylalkyl.

12. The compound of any one of claims 1 to 3 wherein R is optionally

The compound of any one of claims 1 to 3 wherein R is unsubstituted

14. The compound of any one of claims 1 to 3 wherein R is furyl.

15. The compound of any one of claims 1 to 3 wherein R is CHO.

16. The compound of any one of claims 1 to 3 wherein R is as ester.

17. The compound of any one of claims 1 to 3 wherein R is cyano.

18. The compound of any one of claims 1 to 3 wherein Z is an amide.

19. The compound of any one of claims 1 to 3 wherein Z is a branched alkyl ester.

20. The compound of any one of claims 1 to 3 wherein Z is a thioester.

21. The compound of any one of claims 1 to 3 wherein Z is COCH₃.

22. The compound of any one of claims 1 to 3 wherein Z is COCHCH-Z¹ where \ is amino.

23. The compound of any one of claims 1 to 3 wherein Z is a hydroxyalkylamide or polyhydroxyalkylamide.

24. The compound of any one of claims 1 to 3 wherein Z is an amide of an amino saccharide.

25. The compound of any one of claims 1 to 3 wherein Z is optionally substituted oxadiazole.

26. The compound of any one of claims 1 to 3 wherein Ar is 4-chlorophenyl.

27. The compound of claim 1 wherein the compound is of the formula

or a pharmaceutically acceptable salt thereof, wherein

A = O, S, NH, CH₂;

B = hydrogen or OH, or methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, or propargyl, each of which is optionally substituted;

C = methyl, CHX₂, or CH₂X; where X = halo; D = O, S, or aminoguanidinyl;

E = hydrogen, halo, or CH₂(CH₂),jCH3, where n = 0-3;

F = hydrogen or halo; and

G = hydrogen or halo;

28. The compound of claim 26 to wherein B is hydroxy or polyhydroxy substituted, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, or propargyl.

29. The compound of claim 26 wherein F and G are hydrogen.

30. The compound of any one of claims 1 to 3 or 26 to 28 wherein the compound is capable of inhibiting viral replication.

31. The compound of any one of claims 1 to 3 or 26 to 28 wherein the compound is capable of binding with a viral envelope protein.

32. The compound of any one of claims 1 to 3 or 26 to 28 wherein the compound is capable of binding with the viral envelope protein and preventing the virus from continuing its life cycle.

33. A pharmaceutical composition for treating a patient having a virus, the composition comprising one or more compounds of any one of claims 1 to 3 or 26 to 28.

34. The composition of claim 32 further comprising one or more carriers, diluents, or excipients, or a combination thereof.

35. A method for treating a patient having a virus, the method comprising the step of administering to the patient a composistion comprising a therapeutically effective amount of one or more compounds of claims claims 1 to 3 or 26 to 28.

36. The method of claim 34 wherein the composition further comprises one or more carriers, diluents, or excipients, or a combination thereof.

37. The method of claim 35 wherein the virus is a flavivirus.

38. The method of claim 35 wherein the virus is a Dengue fever virus.

39. The method of claim 35 wherein the virus is a yellow fever virus.

40. The compounde of claim 35 wherein the virus is a flavivirus.

41. The compound of claim 35 wherein the virus is a yellow fever virus.

42. The compound of claim 35 wherein the virus is a Dengue fever virus.