Tizoxanide Phosphate and Alkane Sulfonate and Pharmaceutical Applications Thereof

Abstract

The invention relates to tizoxanide phosphate or alkane sulfonate compounds represented by Formula I, and pharmaceutically acceptable salts thereof, isomers thereof, hydrates thereof or solvates thereof, and pharmaceutical applications of the compounds.

##STR00001##

Claims

1. A compound of Formula I, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof, ##STR00023## wherein: X═P or S, when X═P, “” represents a single bond, R.sub.1 and R.sub.2 each are independently hydroxyl or C.sub.1-6alkoxy, said C.sub.1-6alkoxy is optionally substituted by 1-2 substituents independently selected from the group consisting of: aryl, amino, hydroxyl, cyano, nitro, C.sub.1-4alkyl and halogen, said aryl is optionally substituted by 1-2 substituents independently selected from the group consisting of: aryl, amino, hydroxyl,cyano, nitro, C.sub.1-4alkyl and halogen; or when X═S, “” represents a double bond, R.sub.1 is O, R.sub.2 is C.sub.1-6alkyl or aryl, said C.sub.1-6alkyl or aryl is optionally substituted by 1-2 substituents independently selected from the group consisting of: amino, hydroxyl, cyano, nitro, C.sub.1-4alkyl, halogen and tert-butoxycarbonylamino.

2. The compound, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 1, wherein, when X═P, “” represents a single bond, R.sub.1 and R.sub.2 each are independently hydroxyl or C.sub.1-4alkoxy, said C.sub.1-4alkoxy is optionally substituted by 1-2 substituents independently selected from the group consisting of: phenyl, amino, hydroxyl, cyano, nitro, C.sub.1-4alkyl and halogen, said phenyl is optionally substituted by 1-2 substituents independently selected from the group consisting of: amino, hydroxyl, cyano, nitro, C.sub.1-4alkyl and halogen; or when X═S, “” represents a double bond, R.sub.1 is O, R.sub.2 is C.sub.1-4alkyl or phenyl, said C.sub.1-4alkyl or phenyl is optionally substituted by 1-2 substituents independently selected from the group consisting of: amino, hydroxyl, cyano, nitro, C.sub.1-4alkyl, halogen and tert-butoxycarbonylamino.

3. The compound, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 1, wherein, when X═P, “” represents a single bond, R.sub.1 and R.sub.2 each are independently selected from the group consisting of hydroxyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, benzyloxy, phenylethoxy, 1-phenylpropoxy, 1-phenylbutoxy, fluoromethoxy, difluoromethoxy, trifluoromethoxy, chloromethoxy, dichloromethoxy, trichloromethyl, aminomethoxy, aminoethoxy, hydroxylmethoxy, hydroxylethoxy, nitromethoxy and nitroethoxy; or when X═S, “” represents a double bond, R.sub.1 is O, and R.sub.2 is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, p-methylphenyl, m-methylphenyl, o-methylphenyl, aminomethyl, aminoethyl, hydroxylmethyl, hydroxylmethyl, nitromethyl, nitroethyl, tert-butoxycarbonylaminomethyl and tert-butoxycarbonylaminoethyl.

4. The compound, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 1, wherein, when X═P, “” represents a single bond, R.sub.1 and R.sub.2 each are independently selected from the group consisting of hydroxyl, methoxy, ethoxy and benzyloxy; or when X═S, “” represents a double bond, R.sub.1 is O, and R.sub.2 is selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, p-methylphenyl and aminoethyl.

5. The compound, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 1, wherein, when X═P, said salt is an addition salt formed by the compound of Formula I and a base; or when X═S, said salt is an addition salt formed by the compound of Formula I and an acid.

6. The compound, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 1, selected from the group consisting of: Compound 1: dibenzyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate; Compound 2: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl dihydrogen phosphate; Compound 3: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl hydrogen phosphate monosodium salt; Compound 4: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate disodium salt; Compound 5: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate calcium salt; Compound 6: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl methanesulfonate; Compound 7: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl ethanesulfonate; Compound 8: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl 1-propanesulfonate; Compound 9: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl 1-butanesulfonate; Compound 10: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl p-toluenesulfonate; Compound 11: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl N-BOC-taurate; Compound 12: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl taurate hydrochloride; Compound 13: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl taurate Compound 14: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl hydrogen phosphate monopotassium salt; Compound 15: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate dipotassium salt; Compound 16: 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl hydrogen phosphate meglumine salt; Compound 17: dimethyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate; and Compound 18: diethyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate.

7. A pharmaceutical composition, comprising the compound of Formula I, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 1, and a pharmaceutically acceptable carrier or excipient.

8. A method for preparing the compound of Formula I according to claim 1, wherein, when X═P, the method comprises the following steps: in an aprotic solvent, in the presence of carbon tetrachloride and an organic base, and with dimethylaminopyridine (DMAP) as catalyst, tizoxanide is reacted with phosphite of Formula II to obtain the compound of Formula I, and optionally, the compound of Formula I is reacted with a base to form an addition salt; or ##STR00024## when X═S, the method comprises the following steps: tizoxanide is dissolved or suspended in an aprotic solvent, and with an organic base or an inorganic base as an acid receptor, is reacted with R.sub.2-substituted sulfonyl chloride of Formula III, to obtain the compound of Formula I, and optionally, the compound of Formula I is reacted with an acid to form an addition salt, ##STR00025## wherein said R.sub.1 and R.sub.2, as well as “” have the same meanings as defined in claim 1.

9. (canceled)

10. A method for treating and/or preventing a disease in a mammal in need thereof, or a method for inhibiting biofilm formation caused by a bacterium in a mammal in need thereof, comprising administering to the mammal in need thereof a therapeutically and/or prophylactically effective amount of the compound of Formula I or a pharmaceutically acceptable salt, hydrate or solvate thereof according to claim 1, or a pharmaceutical composition comprising the compound of Formula I or a pharmaceutically acceptable salt, hydrate or solvate thereof according to claim 1, wherein the disease includes an infection by a parasite, Hepatitis B (HBV), Hepatitis C (HCV), influenza, a viral infectious disease caused by Rotavirus or Norovirus, or an infection caused by a bacterium.

11. (canceled)

12. The method according to claim 10, wherein the parasite is selected from the group consisting of Giardia, Amoeba, Cryptosporidium, Cyclospora, Trichomonad, Encephalitozoon intestinalis, Isospora belli, Blastocystis hominis, Balantidium colt, Ascaris lumbricoides, Enterocytozoon bieneusi, Tapeworm, Diplacanthus nanus, Giardia lamblia, Leishmania, and Fasciola hepatica.

13. The compound of Formula I, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 1, wherein said halogen is F, Cl, Br or I.

14. The compound of Formula I, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 4, wherein, when X═P, “” represents a single bond, R.sub.1 and R.sub.2 each are independently selected from the group consisting of hydroxyl, methoxy and ethoxy; or when X═S, “” represents a double bond, R.sub.1 is O, and R.sub.2 is selected from the group consisting of methyl, ethyl, n-propyl, n-butyl and aminoethyl.

15. The compound of Formula I, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 4, wherein, when X═P, “” represents a single bond, R.sub.1 and R.sub.2 are the same substituent, selected from the group consisting of hydroxyl, methoxy and ethoxy; or when X═S, “” represents a double bond, R.sub.1 is O, and R.sub.2 is selected from the group consisting of methyl, ethyl, n-propyl, n-butyl and aminoethyl.

16. The compound, or a pharmaceutically acceptable salt, an isomer, a hydrate or a solvate thereof according to claim 5, wherein, when X═P, said salt is monosodium salt, disodium salt, calcium salt, monopotassium salt, dipotassium salt, or meglumine salt; or when X═S, said salt is hydrochlorate, sulphate, acetate, or nitrate.

17. The pharmaceutical composition according to claim 7, wherein said pharmaceutical composition is in the form of a solid preparation, an injection, an external preparation, a spray, a liquid preparation, or a compound preparation.

18. The method according to claim 10, wherein said parasite is protozoan, or helminth.

19. The method according to claim 10, wherein said viral infectious disease caused by Rotavirus or Norovirus is a viral enterogastritis caused by a Rotavirus or a Norovirus.

20. The method according to claim 10, wherein said infection caused by a bacterium is an infection caused by Clostridium difficile, Tubercle bacillus or Helicobacter pylori.

21. The method according to claim 20, wherein said Tubercle bacillus is drug-resistant Tubercle bacillus.

22. The method according to claim 12, wherein said Tapeworm is Taenia saginata or Hymenolepis nana.

Description

DESCRIPTION OF THE DRAWINGS

[0064] FIG. 1: The blood concentration-time curves of tizoxanide (TIZ) in blood after oral administration of nitazoxanide (NTZ), Compound 1, 2, 6, 7, 8, and 9 in mice, respectively;

[0065] FIG. 2: the blood concentration-time curves of tizoxanide (TIZ) in blood after oral administration of nitazoxanide (NTZ), Compound 3, 4, 5, 12, 14, 17 and 18 in mice, respectively.

SPECIFIC MODES FOR CARRYING OUT THE INVENTION

[0066] The embodiments of the invention are described in detail by combining the following examples. However, a person skilled in the art will understand that the following examples are only provided for the purpose of describing the invention, and shall not he regarded as defining the scope of the invention. When the particular conditions are not indicated in Examples, the invention is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or apparatuses, the manufacturers of which are not indicated, are the conventional products that are commercially available.

EXAMPLE 1

Preparation of dibenzyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate (Compound 1)

[0067] ##STR00005##

[0068] To a solution of tizoxanide (3.12 g, 12 mmol) in acetonitrile (150 mL), under the protection of N.sub.2, at 0° C., carbon tetrachloride (9.61 g, 62.4 mmol), diisopropylethylamine (3.4 g, 26.4 mmol), 4-(N,N-dimethylamino)pyridine (180 mg, 1.32 mmol), and dibenzyl phosphite (90%) (6.0 g, 20.6 mmol) are added sequentially, stirred at the same temperature for 3 h. The reaction solution was poured into 450 mL ice water, and washed with 150 mL dichloromethane for three times. The organic phases were combined, and washed with 2 mol/L hydrochloric acid, saturated NaHCO.sub.3 aqueous solution, and saturated saline solution sequentially, then dried with anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure, and the residue was solidified in ether, to obtain the title compound as white powder, with a yield of 79.3%, melting point (mp): 122-123° C., .sup.1H-NMR(DMSO-d6, 400 MHz), δppm, 13.64(1H, brs), 8.66(1H,s), 7.75(1H,d,J=7.6 Hz), 7.64(1H,td,J=8.0 Hz, 2.0 Hz), 7.38-7.43(2H,m), 7.28-7.34(10H,m), 5.12(4H, m).ESI-MS(+Q), 526(MH.sup.+), 548(MNa.sup.+).

EXAMPLE 2

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl dihydrogen phosphate (Compound 2)

[0069] ##STR00006##

[0070] At 0° C., under the protection of N.sub.2, to a suspension of Compound 1 (5.0 g, 9.52 mmoL) in anhydrous acetonitrile (90 mL), bromotrimethylsilane (3.70 mL, 28.33 mmoL) was added, reacted at 0° C. for 3 h, then anhydrous ethanol (2.7 mL, 47 mmoL) was added, and then stirred for 4 h. The resultant mixture was subjected to suction filtration, washed with ethyl acetate, and air-dried to obtain a product as yellow solid powder, 2.63 g, with a yield of 80%; mp: 224-226° C., .sup.1H-NMR (DMSO-d6, 400 MHZ) δ: 8.69(1H,s), 7.67(1H, m), 7.62(1H,m), 7.42(1H,m), 7.32(1H,m). ESI-MS(−Q): 344 [M−H].sup.+; 264 [TIZ−H].sup.+.

EXAMPLE 3

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl hydrogen phosphate monosodium salt (Compound 3)

[0071] ##STR00007##

[0072] Compound 2 (354.23 mg, 1 mmol) prepared in Example 2 was suspended in methanol 20 mL, and 2 mol/L NaOH aqueous solution (0.5 mL, 1 mmol) was added, stirred at room temperature for 20 min, the sample was dissolved completely. The resultant solution was concentrated up to dryness under reduced pressure, and dried in vacuum at 50° C. to obtain the title compound 367 mg, with a yield of 100%, mp: 260-263° C., IR(KBr)cm-1:3448, 1664, 1576, 1478, 1354, 1318, 1279, 1229, 923.

EXAMPLE 4

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate disodium salt (Compound 4)

[0073] ##STR00008##

[0074] Compound 2 (354.23 mg, 1 mmol) prepared in Example 2 was suspended in methanol 20 mL, and 2 mol/L NaOH aqueous solution (1 mL, 2 mmol) was added, stirred at room temperature for 20 min, the sample was dissolved completely. The resultant solution was concentrated up to dryness under reduced pressure, and dried in vacuum at 50° C. to obtain the title compound 398 mg, with a yield of :100%, mp: 192-194° C., IR(KBr)cm-1:3424, 1656, 1477, 1356, 1309, 1215, 1096, 982, 907.

EXAMPLE 5

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate calcium salt (Compound 5)

[0075] ##STR00009##

[0076] Compound 2 (354.23 mg, 1 mmol) prepared in Example 2 was suspended in methanol 20 mL, and 2 mol/L calcium acetate aqueous solution (0.5 mL, 1 mmol) was added. The resultant mixture was stirred at room temperature for 20 min, then concentrated, and then dried at 50° C. in vacuum, to obtain the title compound 313 mg, with a yield of 80%, mp: 238-241° C., IR(KBr)cm-1:3558, 3268, 1662, 1601, 1524, 1468,1365,1316, 1.220, 1170,1106,996,912,738.

EXAMPLE 6

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl methanesulfonate (Compound 6)

[0077] ##STR00010##

[0078] To a solution of tizoxanide (0.50 g, 1.89 mmol) in anhydrous N,N-dimethylformamide (20 mL), triethylamine (0.38 g, 3.78 mmol) was added. The temperature was reduced to 0° C., and methanesulfonyl chloride (0.24 g, 2.07 mmol) was added. The temperature was gradually increased to room temperature, at which the reaction was carried out under stirring. When TLC detection showed that raw materials disappeared, the reaction solution was added into water, and extracted with ethyl acetate. The ethyl acetate phase was washed with water and saturated saline solution sequentially, and dried with anhydrous sodium sulphonate and concentrated, and then was purified by silica gel column chromatography, to obtain the product 0.51 g, with a yield of 86.58%, mp: 188-190° C., .sup.1H-NMR (DMSO-d6, 400 Hz) δ ppm:13.68(1H, s), 8.71(1H,s), 7.83(1H, dd, J=1.82, 8.02 Hz), 7.77-7.72 (1H,m), 7.58-7.54 (2H,m), 3.37(1H,s) .ESI-MS (+Q), m/z:344.1[M+H].sup.+, 366.0[M+Na].sup.+.

EXAMPLE 7

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl ethanesulfonate (Compound 7)

[0079] ##STR00011##

[0080] Except that ethanesulfonyl chloride was used in place of methanesulfonyl chloride to react with tizoxanide, the method of Example 6 was carried out to obtain the title compound, with a yield of 85.93%, mp: 178-180° C., .sup.1H-NMR(DMSO-d6, 400 Hz) δppm: 13.69(s,1H), 8.71(s,1H), 7.82 (dd, J=1.68, 7.56 Hz, 1H), 7.76-7.71(m, 1H), 7.57-7.51(m, 2H), 3.55(q, J=8.0 Hz, 2H), 1.32(t, J=8.0 Hz, 3H). ESI-MS m/z: 358.2[M+H].sup.+, 380.3[M+Na].sup.+.

EXAMPLE 8

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl 1-propanesulfonate (Compound 8)

[0081] ##STR00012##

[0082] Except that 1-propanesulfonyl chloride was used in place of methanesulfonyl chloride to react with tizoxanide, the method of Example 6 was carried out to obtain the title compound, with a yield of 88.57%, mp: 144-146° C., 1H-NMR (DMSO-d6,400 Hz)δppm: 13.68(s,1H), 8.72(s,1H), 7.83-7.71(m,2H), 7.57-7.51(m,2H), 3.52(t,J=8.0 Hz,2H), 1.82-1.76(m,2H), 0.96(t,J=6.0 Hz,3H). ESI-MS(+Q)m/z: 372.0[M+H].sup.+, 394.2[M+N].sup.+.

EXAMPLE 9

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl 1-butanesulfonate (Compound 9)

[0083] ##STR00013##

[0084] Except that 1-butanesulfonyl chloride was used in place of methanesulfonyl chloride to react with tizoxanide, the method of Example 6 was carried out to obtain the title compound, with a yield of 92.03%, mp: 142-144° C., 1H-NMR(CDCl3,400 Hz) δ ppm: 10.81(s,1H), 8.25(s,1H), 8.01(dd,J=1.82, 7.70 Hz, 1H), 7.72-7.55(m,1H), 7.53-7.50(m,2H), 3.47(t,J=8.0,2H), 2.04-2.00(m,2H), 1.57-1.51(m,2H), 0.97(t,J=8.0,3H). ESI-MS m/z: 386 [M+H].sup.+, 408 [M+Na].sup.+.

EXAMPLE 10

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl p-toluenesulfonate (Compound 9)

[0085] ##STR00014##

[0086] Except that p-toluenesulfonyl chloride was used in place of methanesulfonyl chloride to react with tizoxanide, the method of Example 6 was carried out to obtain the title compound, with a yield of 84.81%, mp: 236-238° C., 1H-NMR(DMSO-d6, 400 Hz)δppm:13.37(s, 1H), 8.71(s, 1H), 7.71-7.67(m, 2H), 7.53-7.50(m, 3H), 7.33-7.28(m, 3H), 2.29(s, 3H). ESI-MS m/z:420 [M+H].sup.+, 442 [M+Na].sup.+.

EXAMPLE 11

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl N-Boc-taurate (Compound 11)

[0087] ##STR00015##

[0088] (1) Preparation of N-Boc-tauryl chloride solution: in a dried three-necked flask equipped with a thermometer and a drying pipe, freshly prepared N-Boc-taurine tetrabutylammonium (3.74 g, 8 mmol) was added, and dissolved with dichloromethane (28 mL), and then DMF 0.016 mL was added. The temperature of the resultant solution was reduced to 0° C., triphosgene (0.95 g, 3.2 mmol) was added, and the resultant mixed was gradually warmed to room temperature and reacted for 0.5 h.

[0089] (2) To a suspension of tizoxanide (1.59 g, 6 mmol) in 20 mL DMF, triethylamine (1.41 g, 14 mmol) was added, and the temperature was reduced to 0° C. The N-Boc-tauryl chloride solution prepared in the step (1) was added, and the resultant mixture was warmed to room temperature and reacted for 7 h. The reaction solution was poured into ice water, and the organic phase was separated. The water phase was washed with dichloromethane twice. The washings were combined with the organic phase, washed with dilute hydrochloric acid, washed with water, and washed with saturated NaCl solution, and dried with Na.sub.2SO.sub.4, and then concentrated, then Flash column chromatography (eluent is a mixture of ethyl acetate and petroleum ether at a volume ratio of 1:1) was carried out to obtain the target product, 1.6 g, with a yield of 56%. mp: 164-166° C., 1H-NMR(DMSO-d6,400 Hz) δppm: 13.70(s,1H), 8.71(s,1H), 7.84(m,1H), 7.73(m,1H), 7.56(m,2H), 7.08(t, J=5.6 Hz), 3.64(m,2H),3.41(m,2H), 1.36(s,9H), ESI-MS m/z:473 [M+H]+.

EXAMPLE 12

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl taurate hydrochloride (Compound 12)

[0090] ##STR00016##

[0091] A solution of 1 mol/L HCl in ethyl acetate (10 mL, said solution of HCl in ethyl acetate refers to a solution formed by dissolving HCl gas in ethyl acetate) was cooled to 0° C., and 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl N-Boc-taurate (Compound 11, 472 mg, 1 mmol) prepared in Example 11 was added. The resultant mixture was gradually warmed to room temperature and reacted for 4 h. The reaction solution was filtered under suction to obtain a solid. The solid was first dissolved in methanol, and then was recrystallized by adding isopropanol to obtain the product 380 mg, with a yield of 93%, mp: 168-470° C., .sup.1H-NMR (DMSO-d6, 400 Hz) δ ppm: 13.73(s,1H), 8.72(s,1H), 8.35(brs,3H), 7.87(d,J=7.6 Hz,1H), 7.75-7.79(m,1H), 7.58-7.65(m,2H), 3.96-4.00(m,2H), 3.32(m,2H). ESI-MS m/z:373 [M+H].sup.+.

EXAMPLE 13

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl taurate (Compound 13)

[0092] ##STR00017##

[0093] The 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl taurate hydrochloride (Compound 12) prepared in Example 12 was dissolved in ethyl acetate, and equimolar NaOH aqueous solution was added, stirred sufficiently. The resultant mixture was washed with water, and the organic phase was dried with Na.sub.2SO.sub.4. After concentration, the title compound was obtained.

EXAMPLE 14

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl hydrogen phosphate monopotassium (Compound 14)

[0094] ##STR00018##

[0095] Compound 2 (354.23 mg, 1 mmol) prepared in Example 2 was suspended in methanol 20 mL, and 2 mol/L KOH aqueous solution (0.5 mL, 1 mmol) was added, stirred at room temperature for 20 min., the sample was dissolved completely. The resultant solution was concentrated up to dryness under reduced pressure, and dried in vacuum at 50° C. to obtain the title compound 383 mg, with a yield of 100%, mp: 252-264° C., IR(KBr)cm-1:3423, 3333, 1671, 1528, 1465,1358, 1313, 921.

EXAMPLE 15

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate dipotassium salt (Compound 15)

[0096] ##STR00019##

[0097] Compound 2 (354.23 mg, 1 mmol) prepared in Example 2 was suspended in methanol 20 mL, and 2 mol/L KOH aqueous solution (1 mL, 2 mmol) was added. stirred at room temperature for 20 min, the sample was dissolved completely. The resultant solution was concentrated up to dryness under reduced pressure, and dried in vacuum at 50° C. to obtain the title compound 422 mg, with a yield of 100%. mp: 192-194° C., IR(KBr)cm-1:3424, 1656, 1477, 1356, 1309, 1215, 1096, 982, 907.

EXAMPLE 16

Preparation of 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl hydrogen phosphate meglumine salt (Compound 16)

[0098] ##STR00020##

[0099] Compound 2 (354.23 mg, 1 mmol) prepared in Example 2 was suspended in methanol 20 mL, and a solution of meglumine (195.22 mg, 1 mmol) in methanol 10 ml, stirred at room temperature for 20 min, the resultant mixture was concentrated, and dried at 50° C. in vacuum to obtain the title compound 550 mg, as amorphous solid, with a yield of 100%.

EXAMPLE 17

Preparation of dimethyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate (Compound 17)

[0100] ##STR00021##

[0101] To a solution of tizoxanide (3.12 g, 12 mmol) in acetonitrile (150 mL), under the protection of N.sub.2, at 0° C., carbon tetrachloride (9.61 g, 62.4 mmol), diisopropylethylamine (3.4 g, 26.4 mmol), 4-(N,N-dimethylamino)pyridine (180 mg, 1.32 mmol), and dimethyl phosphite (90%) (2.52 g, 20.6 mmol) were added sequentially, stirred at the same temperature for 3 h, then the reaction solution was poured into 450 mL ice water, and washed with 150 mL dichloromethane for three times. The organic phases were combined, and then washed sequentially with 2 mol/L hydrochloric acid, saturated NaHCO.sub.3 aqueous solution, and saturated saline solution, then dried with anhydrous sodium sulfate, the solvent was removed by distillation under reduced pressure, and the residue was solidified in ether to obtain the title compound 3.2 g, as white powder, with a yield of 72%, mp: 165-167° C., .sup.1H NMR (400 MHz, CDCl3) δ 11.78-11.52 (m, 1H), 8.33 (s, 1H), 8.00 (d, J=8.1 Hz, 1H), 7.61 (td, J=8.1, 1.8 Hz, 1H), 7.45-7.35 (m, 2H), 3.96 (s, 3H), 3.93 (s, 3H). ESI-MS m/z:374 [M+H].sup.+, 396[M+Na].sup.+.

EXAMPLE 18

Preparation of diethyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate (Compound 18)

[0102] ##STR00022##

[0103] To a solution of tizoxanide (3.12 g, 12 mmol) in acetonitrile (150 mL), under the protection of N.sub.2, at 0° C., carbon tetrachloride (9.61 g, 62.4 mmol), diisopropylethylamine (3.4 g, 26.4 mmol), 4-(N,N-dimethylamino)pyridine (180 mg, 1.32 mmol), and diethyl phosphite (98%) (2.90 g, 20.6 mmol) were added sequentially, followed by stirring at the same temperature for 3 h. The reaction solution was poured into 450 mL ice water, and washed with 150 mL dichloromethane for three times. The organic phases were combined, washed sequentially with 2 mol/L hydrochloric acid, saturated NaHCO.sub.3 aqueous solution, and saturated saline solution, and dried with anhydrous sodium sulfate, the solvent was removed by distillation under reduced pressure, and the residue was solidified in ether to obtain the title compound 3.6 g, as white powder, with a yield of 75%, mp: 138-138° C., .sup.1H NMR (400 MHz, CDCl3) δ 11.83-11.68 (m, 1H), 8.37 (s, 1H), 8.03 (d, J=7.6 Hz, 1H), 7.60 (t, J=7.6 Hz, 1H), 7.46-7.34 (m, 2H), 4.31 (dd, J=15.0, 7.2 Hz, 4H), 1.38 (t, J=7.2 Hz, 6H). ESI-MS m/z:402 [M+H].sup.+, 424[M+Na].sup.+.

EXAMPLE 19

Pharmacokinetic Evaluation and Result of Oral Administration of Drug in Mice

[0104] Sample preparation: 32.57 μmol of a test compound was dissolved in 100 μL dimethyl sulfoxide (DMSO), with the addition of 10 mL 0.5% Carboxyl Methyl Cellulose Sodium (CMC-Na) solution, to prepare a sample at 3.257 μmol/mL.

[0105] The test compounds refer to the compounds prepared in Examples of the invention and the positive control compound nitazoxanide. The experiment was carried out in two batches, wherein the first hatch of test compounds were Compound 1, 2, 6, 7, 8, 9 and the positive control compound nitazoxanide; and the second batch of test compounds were Compound 3, 4, 5, 12, 14, 17, 18 and positive control compound nitazoxanide.

[0106] Experimental method: ICR mice (SPS grade, male, 25±2 mg), purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd., were grouped randomly depending on body weight, 3 mice for each group. Nitazoxanide and a test compound were intragastrically administered separately to each mouse at a dose of 10 mL/kg (i.e., 32.57 μmol/kg of corresponding drug to each mouse), wherein nitazoxanide was used as positive control, and 0.1 ml blood was taken from veins of Fundus Oculi at 0.08, 0.25, 0.5, 1, 2, 4, 6, 8 and 12 h after administration, placed in a Heparin Sodium-containing centrifuge tube, and centrifuged for 20 min (at a relative centrifugal force (RCF) of 3000 g). The plasma was taken and stored in a −20° C. refrigerator for further detection.

[0107] During the detection, 50 μL plasma was taken, with the addition of an internal standard solution (5000 ng/mL glipizide aqueous solution, 10 μL), and the addition of acetonitrile (200 μL), and then mixed well. The mixture was vortexed for 3 min, and centrifuged for 10 min (at a relative centrifugal force (RCF) of 8500 g). The supernatant (50 μL) was well mixed with water (50 μL), and 10 μL was drawn for LC/MS/MS analysis, so as to detect the blood concentration of tizoxanide. The results are shown in Table 1, Table 2, Table 3, Table 4, FIG. 1, and FIG. 2.

TABLE-US-00001 TABLE 1 Blood concentrations (Mean ± SD, n = 3) of tizoxanide (TIZ) after oral administration of the compound nitazoxanide (NTZ) and Compound 1, 2, 6, 7, 8, 9 in mice, respectively Blood concentration (ng/mL) time nitazoxanide (h) (NTZ) Compound 1 Compound 2 Compound 6 Compound 7 Compound 8 Compound 9 0.08 127.23 ± 22.46  329.85 ± 37.88  480.66 ± 149.04 48.59 ± 43.66 619.23 ± 131.29 19.43 ± 7.97 9.64 ± 4.60 0.25 329.39 ± 111.17 148.92 ± 24.08  195.50 ± 19.09  67.85 ± 6.50  360.27 ± 108.54 118.19 ± 21.09 83.17 ± 24.73 0.5 94.65 ± 24.48 92.03 ± 11.37 60.77 ± 24.24 103.21 ± 32.66  149.92 ± 2.98  279.55 ± 91.07 256.43 ± 108.32 1 19.69 ± 5.62  48.61 ± 8.32  22.30 ± 0.75  62.11 ± 37.77 81.50 ± 0.62   425.24 ± 185.79 350.02 ± 81.51  2 13.91 ± 3.60  13.39 ± 2.27  17.66 ± 17.49 36.89 ± 9.46  13.63 ± 4.06   458.74 ± 105.51 495.02 ± 93.24  4 8.22 ± 5.08 4.18 ± 1.51 6.83 ± 6.01 23.95 ± 15.44 4.39 ± 1.92 276.56 ± 30.93 261.54 ± 101.72 6 3.46 ± 1.66 6.14 ± 4.10 2.30 ± 1.98 8.79 ± 4.53 0.38* 121.68 ± 24.75 67.19 ± 39.27 8 0.61 ± 0.12 2.90 ± 1.04 ND 15.14 ± 16.34 ND 115.25 ± 97.00 190.64 ± 159.27 12 4.90 ± 6.45 0.51 ± 0.04 0.24* 0.20* 160.27 ± 108.54  30.30 ± 19.55 31.88 ± 26.74 Note: ND: lower than limit of quantitation; *a group of measured values, no SD value

TABLE-US-00002 TABLE 2 Blood concentrations (Mean ± SD, n = 3) of tizoxanide (TIZ) after oral administration of the compound nitazoxanide (NTZ) and Compound 3, 5, 12, 14, 17, 18 in mice, respectively blood concentration (ng/mL) time nitazoxanide (h) (NTZ) Compound 3 Compound 5 Compound 12 Compound 14 Compound 17 Compound 18 0.08 86.46 ± 40.97 297.33 ± 35.74  243.54 ± 150.44 822.63 ± 66.11 194.90 ± 28.73  673.15 ± 144.19 114.79 ± 40.96 0.25 66.67 ± 39.16 45.68 ± 12.91 62.78 ± 18.56 1108.79 ± 231.35 45.812 ± 12.07  775.87 ± 184.95 333.65 ± 48.75 0.5 12.28 ± 5.86  35.49 ± 14.89 30.27 ± 17.02 1035.27 ± 208.56 24.38 ± 3.82 523.92 ± 81.61 335.98 ± 88.56 1 11.90 ± 1.00  19.83 ± 8.06  13.28 ± 4.02   900.50 ± 315.32 29.36 ± 3.83 367.09 ± 61.76 359.85 ± 67.39 2 4.65 ± 2.62 18.75 ± 4.75  10.14 ± 5.43  800.59 ± 54.04  8.64 ± 4.27 127.95 ± 12.91  395.59 ± 183.65 4 7.57 ± 2.32 9.04 ± 5.39 7.50 ± 2.43  422.98 ± 178.48  4.71 ± 2.33 40.80 ± 2.68 163.62 ± 82.72 6 4.43 ± 2.15 1.63 * 2.66 ± 1.09 141.20 ± 4.14   6.65 ± 5.84  21.21 ± 23.33  78.99 ± 37.79 8 1.54 ± 0.55 2.16 ± 1.30 1.49 ± 0.28 50.31 ± 8.74  2.06 ± 1.00  4.99 ± 61.83  78.66 ± 36.77 12 NB 25.06 ± 1.72 1.05  12.71 ± 13.04

TABLE-US-00003 TABLE 3 Pharmacokinetic parameters (Mean ± SD, n = 3) calculated as tizoxanide (TIZ), after oral administration of nitazoxanide (NTZ) and Compound 1, 2, 6, 7, 8, 9 in mice Parameter values nitazoxanide Parameters Unit (NTZ) Compound 1 Compound 2 Compound 6 Compound 7 Compound 8 Compound 9 T.sub.max h 0.25 ± 0.08 ± 0.08 ± 0.50 ± 0.80 ± 1.67 ± 2.00 ± 0.00 0.00 0.00 0.00 0.00 0.58 0.00 C.sub.max ng/mL 329.4 ±  329.8 ±  480.7 ±  103.2 ±  619.2 ±  474.8 ±  495.0 ±  111.2 37.9 149.0 32.7 131.3 128.1 93.2 Ke 1/h 0.41 ± 0.37 ± 0.72 ± 0.37 ± 0.62 ± 0.32 ± 0.33 ± 0.23 0.11 0.26 0.20 0.01 0.05 0.19 t.sub.1/2 h 2.02 ± 1.95 ± 1.09 ± 2.22 ± 1.22 ± 2.23 ± 2.54 ± 0.92 0.59 0.51 1.23 0.02 0.36 1.18 AUC.sub.0-t h*ng/mL 185.8 ±  193.9 ±  183.1 ±  245.3 ±  330.2 ±  2158.4 ±  2413.0 ±  18.3 14.7 6.5 84.1 39.0 759.6 631.9 AUC.sub.0-∞ h*ng/mL 198.5 ±  195.3 ±  187.7 ±  305.1 ±  345.1 ±  2313.5 ±  2559.1 ±  28.5 15.1 2.5 168.0 33.0 640.4 701.9 MRT.sub.0-t h 1.46 ± 1.52 ± 0.90 ± 2.53 ± 0.73 ± 3.29 ± 4.05 ± 0.81 0.17 0.08 0.24 0.03 0.57 0.68 MRT.sub.0-∞ h 2.15 ± 1.62 ± 1.08 ± 3.91 ± 0.87 ± 3.90 ± 4.73 ± 1.66 0.15 0.18 2.16 0.20 0.48 1.10 F.sub.(    .sub. ) % 100 104.35 ±  98.54 ±  132.04 ±  174.24 ±  1161.56 ±   1298.60 ±   7.93 3.49 45.27 21.01 408.79 340.06

TABLE-US-00004 TABLE 4 Pharmacokinetic parameters (Mean ± SD, n = 3) calculated as tizoxanide (TIZ), after oral administration of nitazoxanide (NTZ) and Compound 3, 5, 12, 14, 17, 18 in mice Parameter values nitazoxanide Parameters Unit (NTZ) Compound 3 Compound 5 Compound 12 Compound 14 Compound 17 Compound 18 T.sub.max h 0.14 ± 0.08 ± 0.08 ± 0.33 ± 0.08 ± 0.25 ± 1.67 ± 0.10 0.00 0.00 0.14 0.00 0.00 0.58 C.sub.max ng/mL 101.1 ± 297.3 ± 243.5 ± 1214.5 ± 194.9 ± 775.9 ± 460.5 ± 36.7 35.7 150.4 53.3 28.7 185.0 74.8 Ke 1/h 0.34 ± 0.52 ± 0.44 ± 0.36 ± 0.51 ± 0.50 ± 0.37 ± 0.07 0.22 0.07 0.00 0.27 0.08 0.24 t.sub.1/2 h 2.07 ± 1.49 ± 1.60 ± 1.92 ± 1.60 ± 1.41 ± 2.47 ± 0.39 0.52 0.27 0.01 0.66 0.23 1.46 AUC.sub.0-t h*ng/mL 69.2 ± 122.6 ± 99.1 ± 3929.6 ± 97.0 ± 1079.5 ± 1820.3 ± 3.7 17.1 37.5 478.4 17.2 70.6 392.3 AUC.sub.0-∞ h*ng/mL 76.0 ± 127.6 ± 102.8 ± 3998.8 ± 101.8 ± 1176.6 ± 1883.3 ± 7.9 19.3 37.1 481.9 17.9 220.7 382.2 MRT.sub.0-t h 2.10 ± 1.37 ± 1.42 ± 2.60 ± 1.53 ± 1.61 ± 3.34 ± 0.42 0.33 0.26 0.15 0.64 0.24 0.42 MRT.sub.0-∞ h 2.79 ± 1.66 ± 1.78 ± 2.81 ± 1.90 ± 2.21 ± 3.81 ± 0.58 0.44 0.38 0.16 0.74 1.07 0.61 F.sub.(    .sub. ) % — 148.3 ± 114.8 ± 3956.7 ± 112.4 ± 1284.5 ± 2014.6 ± 20.7 43.5 476.8 19.9 84.0 434.1

[0108] The pharmacokinetic screening results after oral administration in mice show (see Table 1, Table 2, Table 3, Table 4, FIG. 1, and FIG. 2):

[0109] (1) Like nitazoxanide (NTZ), Compound 1, 2, 6, 7, 8, 9 and Compound 3, 4, 5, 12, 14, 17, 18 could be converted to the active form tizoxanide in vivo after oral administration in mice, and the conversion was relatively complete.

[0110] (2) After oral administration in mice, nitazoxanide-substituted phosphate compound—dibenzyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate (Compound 1) had a shorter time to peak (Tmax) of tizoxanide in blood than that of the positive control agent nitazoxanide, had a Cmax similar to that of nitazoxanide, had an Area Under concentration-time Curve (AUC) slightly higher than that of nitazoxanide, and had a bioavailability (F) (calculated as tizoxanide) 1.04-fold higher than that of nitazoxanide. As to the other two nitazoxanide-substituted phosphate compounds—dimethyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate (Compound 17) and diethyl 2-(5-nitrothiazol-2-yl-carbamoyl)phenyl phosphate (Compound 18), after oral administration in mice, they had a longer Tmax of tizoxanide in blood than that of the positive control agent nitazoxanide, had a Cmax and AUC obviously higher than that of nitazoxanide, and had a bioavailability (F) (calculated as tizoxanide) that was 12.8-fold and 20.1-fold of that of nitazoxanide.

[0111] (3) After oral administration, nitazoxanide dihydrogen phosphate (2-(5-nitrothiazol-2-yl-carbamoyl)phenyl dihydrogen phosphate, Compound 2), and salts thereof—including monosodium salt (Compound 3), disodium salt (Compound 4), calcium salt (Compound 5), and monopotassium (Compound 14), had a shorter time to peak (Tmax) of tizoxanide in blood than that of the positive agent nitazoxanide, had a higher Cmax than nitazoxanide, and had a bioavailability (F) (calculated as tizoxanide) similar to that of nitazoxanide.

[0112] (4) After oral administration in mice, tizoxanide alkane sulfonate compounds, including methanesulfonate (Compound 6), ethanesulfonate (Compound 7), tizoxanide propanesulfonate (Compound 8), tizoxanide butanesulfonate (Compound 9) and taurate hydrochloride (Compound 12), had a delayed time to peak (Tmax) of tizoxanide in blood compared to the positive agent nitazoxanide, had a significantly increased Cmax value compared to the positive compound nitazoxanide (except for Compound 6), and had a Mean Retention Time (MRT.sub.0-∞) of tizoxanide an vivo and an Area Under concentration-time Curve (AUC) much higher than that of nitazoxanide, and had a bioavailability (F) (calculated as tizoxanide) that was 1.32-fold, 1.74-fold, 11.6-fold, 13.0-fold and 39.6-fold of that of nitazoxanide, and were superior to nitazoxanide in some aspects.

EXAMPLE 20

Pharmacokinetic Evaluation of Oral Administration and Intravenous Injection of Nitazoxanide and Compound 3 in Rats

[0113] 9 SD rats (SPF grade, male, 200±10 g), provided by Laboratory Animal Center of the Academy of Military Medical Sciences, were grouped randomly, 3 mice for each group.

[0114] (1) Intravenous injection group of Compound 3: a dose of 5 mg/kg (equivalent to a dose of 13.67 μmol/kg tizoxanide); administration volume: 0.2 mL/200 g rat (preparation of a test solution: 15.00 mg Compound 3 prepared in Example 3 was weighed accurately and dissolved by adding 100 μL DMSO, and then sterile water was added to prepare a clear solution at 5 mg/mL), after intravenous injection of Compound 3 to the tail of rat, blood was taken at 0.03, 0.08, 0.25, 0.5, 1, 2, 4, 6, 8, 12, and 24 h after administration. The plasma was separated and stored in a −20° C. refrigerator for further detection.

[0115] (2) Oral administration group of Compound 3, a dose of 15 mg/kg (equivalent to a dose of 41 μmol/kg tizoxanide); administration volume: 2 mL/200 g rat (to the solution of Compound 3 (5 mg/mL) prepared above, sterile water was added to prepare a clear solution at 1.5 mg/mL); after oral administration of Compound 3 (a dose of 15 mg/kg) in rats, blood was taken at 0.08, 0.25, 0.5, 1, 2, 4, 6, 8, 12 and 24 h after administration. The plasma was separated and stored in a −20° C. refrigerator for further detection.

[0116] (3) Oral administration group of nitazoxanide: a dose of 12.5 mg/kg (equivalent to a dose of 41 μmol/kg tizoxanide); administration volume: 2 mL/200 g rat (preparation of a test solution: 10.96 mg nitazoxanide was weighed accurately and dissolved by adding 600 μL DMSO, and 8.768 mL sterile water was added to prepare a clear solution at 1.25 mg/mL); after oral administration of nitazoxanide at 12.5 mg/kg in rats, blood was taken before administration and at 0.08, 0.25, 0.5, 1, 2, 4, 6, 8, 12 and 24 h after administration. The plasma was separated and stored in a −20° C. refrigerator for further detection.

[0117] Treatment of plasma sample: 100 μL plasma was taken, 300 μL acetonitrile solution containing internal standard (500 nmol/L a solution of tolbutamide in acetonitrile) was added, and then mixed well. The mixture was vortexed for 1 min, and centrifuged at 4° C. for 10 min (at a relative centrifugal force (RCF) of 14000 g). The supernatant was taken, and 20 μL was drawn for LC/MS/MS analysis, so as to detect the blood concentration of tizoxanide and the prototype drug. The results are shown in Table 5 and Table 6.

TABLE-US-00005 TABLE 5 Blood concentration after oral administration or intravenous injection of Compound 3 and oral administration of nitazoxanide Oral administration Intravenous injection of Oral administration of of nitazoxanide Compound 3 (5 mg/kg) Compound 3 (15 mg/kg) (15 mg/kg) plasma plasma plasma plasma plasma concentration concentration concentration concentration concentration of Compound 3 of tizoxanide of Compound of tizoxanide of tizoxanide Time (ng/mL) (ng/mL) 3 (ng/mL) (ng/mL) (ng/mL) (h) Mean ± SD Mean ± SD Mean ± SD Mean ± SD Mean ± SD 0.03 26739.2 ± 6592.9 23315.3 ± 12019.0 55.3 ± 2.1 3053.5 ± 1860.6 677.3 ± 541.5 0.08 13255.6 ± 1386.3 18111.1 ± 8851.7   99.1 ± 22.1 2714.4 ± 1452.6 956.9 ± 408.1 0.25  3970.6 ± 1879.8 9856.5 ± 807.3  71.1 ± 7.3 1603.5 ± 891.8  989.0 ± 234.6 0.5  1730.3 ± 1249.3 5186.9 ± 763.4  33.0 ± 3.2 451.3 ± 52.4  743.7 ± 156.4 1  345.0 ± 316.5 1720.7 ± 899.3  24.4 ± 1.6 502.7 ± 513.2 235.4 ± 151.2 2 113.0 ± 83.4 343.8 ± 117.7 — 225.2 ± 257.2 60.1 ± 68.0 4 13.9 ± 1.9 31.2 ± 27.1 — 43.7 ± 22.6 37.9 ± 47.6 6 — 11.6 ± 10.4 — 153.7 ± 234.5 33.0 ± 28.0 12 — — 12.8 ± 5.9  21.1 ± 16.9

TABLE-US-00006 TABLE 6 Pharmacokinetic parameters (Mean ± SD, n = 3) after oral administration or intravenous injection of Compound 3 and oral administration of nitazoxanide in rats plasma concentration of tizoxanide plasma concentration of Compound 3 intravenous oral oral intraveneus oral injection of administration administration injection of administration Compound 3 of Compound 3 of nitazoxanide Compound 3 of Compound 3 Parameters Unit (5 mg/kg) (15 mg/kg) (12.5 mg/kg) (5 mg/kg) (15 mg/kg) C.sub.max μg/mL 23.32 ± 12.02 3.05 ± 1.86 0.989 ± 0.23  26.74 ± 6.59  0.10 ± 0.02 T.sub.max h — 0.22 ± 0.24 0.42 ± 0.14 — 0.25 ± 0.00 t.sub.1/2z h 0.50 ± 0.04 2.03 ± 0.37 3.16 ± 0.82 0.48 ± 0.28 1.67 ± 1.67 AUC.sub.(0-t) μg/L*h 9199.0 ± 715.7  3378.7 ± 746.2  1967.1 ± 982.2  4916.5 ± 785.6  118.6 ± 50   AUC.sub.(0-∞) μg/L*h 9204.1 ± 712.7  3433.1 ± 718.9  1996.9 ± 974.1  4921.5 ± 785.9  153.8 ± 76.3  MRT.sub.(0-t) h 0.47 ± 0.18 1.87 ± 0.65 2.01 ± 1.18 0.26 ± 0.15 1.22 ± 0.83 CL.sub.z/F L/h/kg 0.55 ± 0.04 4.50 ± 0.94 7.34 ± 3.46 1.03 ± 0.17 112.79 ± 47.03  V.sub.z/F L/kg 0.39 ± 0.05 13.53 ± 5.20  32.67 ± 16.81 0.69 ± 0.38 197.89 ± 118.02 F % — 12.2 7.2 — 2.4

[0118] The pharmacokinetic evaluation results after oral administration or intravenous injection of Compound 3 and oral administration of nitazoxanide in rats show (see Table 5, Table 6):

[0119] (1) Compound 3 has a solubility much better than nitazoxanide, with a solubility >1.0 mg/mL, can be prepared into a solution, and be administered orally or by intravenous or intramuscular injection, while nitazoxanide can only be administered orally in the form of suspension.

[0120] (2) Compound 3 can be quickly converted to its active form tizoxanide, no matter by oral administration or intravenous injection, and the concentration of prototype drug is smaller than that of tizoxanide.

[0121] (3) After oral administration of a solution of Compound 3 (1.5 mg/kg, equivalent to a dose of 41 μmol/kg tizoxanide) and a suspension of nitazoxanide (12.5 mg/kg, equivalent to a dose of 41 μmol/kg tizoxanide), the Compound 3 had a peak plasma concentration of 3.05±1.86 μg/mL for the active product tizoxanide, and an Area Under concentration-time Curve (AUC) of 3433.1±718.9 μg/L*h. Nitazoxanide had a peak plasma concentration of 0.989±0.23 μg/mL for the active product tizoxanide, and an Area Under concentration-time Curve (AUC) of 1996.9±974.1 μg/L*h. Compound 3 had a Cmax and a AUC value that were 3.1-fold and 1.7-fold of that of nitazoxanide, respectively. It can be determined by calculation that as compared to intravenous injection, Compound 3 had a bioavailability of 12.2% by oral administration in rats, while nitazoxanide had a bioavailability of 7.2%.

[0122] (4) After intravenous injection of a solution of Compound 3 (5 mg/kg), the Cmax value was 23.32 μg/ml, for tizoxanide in blood, and the Area Under concentration-time Curve [AUC(0-∞)] was 9204.1 μg/L*h, as calculated as tizoxanide. While after oral administration of nitazoxanide (12.5 mg/kg) in a 3-fold molar dose, the Cmax value for tizoxanide in blood was 0.989 μg/mL, and the Area Under concentration-time Curve [AUC(.sub.0-∞)] was 1996.9 μg/L*h. With the comparison of intravenous injection of Compound 3 with oral administration of nitazoxanide, the former was significantly superior with respect to the two parameters, i.e., Cmax and Area Under concentration-time Curve AUC (0-∞) as calculated as tizoxanide.

[0123] Conclusion: after oral administration of the tizoxanide alkane sulfonate compounds (such as Compound 6, 7, 8, 9 and 12) and the nitazoxanide-substituted phosphate compounds (such as Compound 17, 18) synthesized in the invention, the Cmax of tizoxanide in blood was significantly increased, and the bioavailability (F) calculated as tizoxanide was much higher than that of nitazoxanide. The tizoxanide dihydrogen phosphate compounds (such as Compound 2) and salts thereof (such as Compound 3, 4, 5, 14) synthesized in the invention, were similar to nitazoxanide in terms of bioavailability (F), but were much better than nitazoxanide in terms of solubility, and therefore can not only be administered orally, but also be injected intravenously. It is found by test that tizoxanide dihydrogen phosphate monosodium salt (Compound 3) administered intravenously was much better than nitazoxanide administered orally, with respect to the parameters such as blood concentration and bioavailability.