# Patent

## Title
Treatment of inflammatory bowel disease

## Abstract

Disclosed herein is a method comprising administering a compound to a mammal suffering from an inflammatory bowel disease for the treatment of said disease, said compound having a structure according to Formula I




wherein X, Y, B, R2, R3, R4, R5, R6 and n have the meanings found herein.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of pending U.S. patent application Ser. No. 10/772,720, filed Feb. 4, 2004; which is a continuation-in-part of pending U.S. patent application Ser. No. 10/365,369, filed Feb. 11, 2003.


DESCRIPTION OF RELATED ART
Prostaglandins can be described as derivatives of prostanoic acid which have the following structural formula:




Various types of prostaglandins are known, depending on the structure and substituents carried on the alicyclic ring of the prostanoic acid skeleton. Further classification is based on the number of unsaturated bonds in the side chain indicated by numerical subscripts after the generic type of prostaglandin [e.g. prostaglandin E1 (PGE1), prostaglandin E2 (PGE2)], and on the configuration of the substituents on the alicyclic ring indicated by α or β [e.g. prostaglandin F2α (PGF2β)].
Prostaglandins are useful for the long-term medical management of glaucoma (see, for example, Bito, L. Z. Biological Protection with Prostaglandins, Cohen, M. M., ed., Boca Raton, Fla., CRC Press Inc., 1985, pp. 231-252; and Bito, L. Z., Applied Pharmacology in the Medical Treatment of Glaucomas Drance, S. M. and Neufeld, A. H. eds., New York, Grune & Stratton, 1984, pp. 477-505. Such prostaglandins include PGF2α, PGF1α, PGE2, and certain lipid-soluble esters, such as C1 to C2 alkyl esters, e.g. 1-isopropyl ester, of such compounds.
Certain 15,15-dimethyl prostaglandins with antihypertensive, gastric acid secretion inhibition, and smooth muscle stimulant properties, are known to have improved metabolic stability. These are described in documents such as the following:

    Pernet et al in U.S. Pat. No. 4,117,014 (filed 23 Dec. 1976);
    Pernet, Andre G. et al., Prostaglandin analogs modified at the 10 and 11 positions, Tetrahedron Letters, (41), 1979, pp. 3933-3936;
    Plantema, Otto G. et al., Synthesis of (.+−.)-10,10-dimethylprostaglandin E1 methyl ester and its 15-epimer, Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-organic Chemistry (1972-1999), (3), 1978, pp. 304-308;
    Plantema, O. G. et al., Synthesis of 10,10-dimethylprostaglandin E1, Tetrahedron Letters, (51), 1975, 4039;
    Hamon, A., et al., Synthesis of (+−)- and 15-EPI(+−)-10,10-Dimthylprostaglandin E1, Tetrahedron Letters, Elsevier Science Publishers, Amsterdam, NL, no. 3, January 1976, pp. 211-214; and
    Patent Abstracts of Japan, Vol. 0082, no. 18 (C-503), Jun. 10, 1988 & JP 63 002972 A (Nippon lyakuhin Kogyo KK), 7 Jan. 1988;

the disclosure of these documents are hereby expressly incorporated by reference.



Inflammatory bowel disease (IBD) is a group of disease characterized by inflammation in the large or small intestines and is manifest in symptoms such as diarrhea, pain, and weight loss. Nonsteroidal anti-inflammatory drugs have been shown to be associated with the risk of developing IBD, and recently Kabashima and colleagues have disclosed that “EP4 works to keep mucosal integrity, to suppress the innate immunity, and to downregulate the proliferation and activation of CD4+ T cells. These findings have not only elucidated the mechanisms of IBD by NSAIDs, but also indicated the therapeutic potential of EP4-selective agonists in prevention and treatment of IBD.” (Kabashima, et. al., The Journal of Clinical Investigation, April 2002, Vol. 9, 883-893).
SUMMARY OF THE INVENTION
Disclosed herein is a method comprising administering a compound to a mammal suffering from an inflammatory bowel disease for the treatment of said disease, said compound having a structure according to Formula I




wherein the dashed line indicates the presence or absence of a bond, the hatched wedge indicates the α (down) configuration, and the solid triangle indicates the β (up) configuration;

B is a single, double, or triple covalent bond;

n is 0-6;

X is CH2, S or O;

Y is any pharmaceutically acceptable salt of CO2H, or CO2R, CONR2, CONHCH2CH2OH, CON(CH2CH2OH)2, CH2OR, P(O)(OR)2, CONRSO2R, SONR2, or





R is H, C1-6 alkyl or C2-6 alkenyl;

R2 and R3 are C1-6 linear alkyl which may be the same or different, and may be bonded to each other such that they form a ring incorporating the carbon to which they are commonly attached;

R4 is hydrogen, R, C(═O)R, or any group that is easily removed under physiological conditions such that R4 is effectively hydrogen;

R5 is hydrogen or R;

R6 is

    
    
        i) hydrogen;
        ii) a linear or branched hydrocarbon containing between 1 and 8 carbon atoms, which may contain one or more double or triple bonds, or oxygen or halogen derivatives of said hydrocarbon, wherein 1-3 carbon or hydrogen atoms may be substituted by O or a halogen; or
        iii) aryloxy, heteroaryloxy, C3-8 cycloalkyloxy, C3-8 cycloalkyl, C6-10 aryl or C3-10 heteroaryl, wherein one or more carbons is substituted with N, O, or S; and which may contain one or more substituents selected from the group consisting of halogen, trihalomethyl, cyano, nitro, amino, hydroxy, C6-10 aryl, C3-10 heteroaryl, aryloxy, heteroaryloxy, C1-6 alkyl, OR, SR, and SO2R.
    
    


Compositions and medicaments related thereto are also disclosed.



BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIGS. 1-9 illustrate possible ways to prepare compounds of the invention.



DETAILED DESCRIPTION OF THE INVENTION
Treatment of inflammatory bowel disease may be accomplished by the administration of the compounds described herein to the suffering mammal. Inflammatory bowel disease describes a variety of diseases characterized by inflammation of the bowels including, but not limited to, ulcerative colitis and Crohn's disease. Treatment may be accomplished by oral administration, by suppository, or parenteral administration, or some other suitable method.
The compounds used in the treatment described herein have a structure according to Formula I




A preferred group of the compounds of the present invention includes compounds that do not have the following structural formula II:




wherein A is CO2H, CO2Me, or CO2Et;

D is a single, double, or triple covalent bond;

E is a linear, branched, or cycloalkyl chain of 3 to 7 carbons, trifluoromethylbutyl, hydroxylalkyl, or CH2R7 wherein R7 is phenyl, cyclopentyl, phenoxy, chlorophenoxy, propoxy, or —CH2SCH2CH3;

J is hydrogen, R, C(═O)R, or any group that is easily removed under physiological conditions such that R4 is effectively hydrogen; and

G is H or CH3.

As used herein, the symbols “Me” and “Et” refer to the moieties commonly referred to as “methyl” and “ethyl” by those of ordinary skill in the art.
In other compounds related to Formula I and Formula II, A is CO2R8, wherein R8 is any linear, branched, or cyclic alkyl group having from 3 to 6 carbons.
Another preferred group includes compounds having formula III:




Another preferred group includes compounds having formula IV:





Another preferred group includes compounds having formula V:





wherein at least one of R2 and R3 is not methyl.

In the above formulae, the substituents and symbols are as hereinabove defined.
In the above formulae:
Preferably Y is any pharmaceutically acceptable salt of CO2H or CO2R. More preferably Y is CO2H or CO2Me.
Preferably n is 2.
Preferably, R6 is C6-10 aryl or C3-10 heteroaryl, which may contain one or more substituents selected from the group consisting of halogen, trihalomethyl, cyano, nitro, amino, hydroxy, C1-6 alkyl, OR, SR, and SO2R. More preferably R6 is phenyl, napthyl, benzofuranyl, or benzothienyl, which may contain one or more substituents selected from the group consisting of halogen, trihalomethyl, cyano, nitro, amino, hydroxy, C1-6 alkyl, OR, SR, and SO2R. Most preferred is 3-chlorobenzothien-2-yl.
Another preferred group includes compounds having formula XIII:




wherein B represents a single or double bond;

and R6 is napthyl, benzofuranyl, or benzothienyl, which may contain one or more substituents selected from the group consisting of halogen, trihalomethyl, cyano, nitro, amino, hydroxy, C1-6 alkyl, OR, SR, and SO2R.

Compounds useful for the methods described herein may be prepared by methods known to those skilled in the art. The synthesis of several of these compounds is illustrated in Schemes 2-7. These Schemes that are included herein are merely illustrative and are not intended to limit the scope of the invention in any way. Although there are several ways the reduction of compounds of Formula VI to Formula VII could be incorporated into the synthesis of these compounds, one convenient way to this is shown in Scheme 2. In this Scheme, compound 2 is a compound of Formula VI and compound 3 is a compound of formula VII. However, those skilled in the art will recognize that there are many ways in which the reduction could be used to prepare compounds of this invention.









TABLE 1






Low Rf
High Rf


Structure
diastereomer
diastereomer











21
22


 






23
24


 






34
35


 






36
37


 






38
39


 






40
41


 












42


 






43


 






44


 






45


 













46
47


 






48
49


 






50
51


 






52
53


 






54
55


 






56
57


 






58
59


 






60
61


 






62
63


 






64
65


 






66
67


 






68
69


 






70
71


 






72
73


 






74
75









The compounds named below, and illustrated in Table 1, are especially preferred representatives of the compounds of the present invention:

    (3-{(1R,4S,5S)-5-(3-chloro-benzo[b]thiophen-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentylsulfanyl}-propylsulfanyl)-acetic acid methyl ester (21, 22);
    (3-{(1R,4S,5S)-5-(3-chloro-benzo[b]thiophen-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentylsulfanyl}-propylsulfanyl)-acetic acid (23, 24);
    (Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-ynoic acid methyl ester (34, 35);
    (Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-ynoic acid (36,37);
    (Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-enoic acid methyl ester (38,39);
    (Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-enoic acid (40,41);
    7-[(1R,4S,5R)-4-Hydroxy-5-((E)-(S)-3-hydroxy-oct-1-enyl)-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-ynoic acid methyl ester (42)
    7-[(1R,4S,5R)-4-Hydroxy-5-((E)-(S)-3-hydroxy-oct-1-enyl)-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-ynoic acid (43)
    (Z)-7-[(1R,4S,5R)-4-Hydroxy-5-((E)-(S)-3-hydroxy-oct-1-enyl)-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid (44)
    (Z)-7-[(1R,4S,5R)-4-Hydroxy-5-((E)-(S)-3-hydroxy-oct-1-enyl)-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid methyl ester (45)
    (Z)-7-[(1R,4S,5R)-4-Hydroxy-5-((E)-3-hydroxy-4-phenyl-but-1-enyl)-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid (46, 47)
    (Z)-7-[(1R,4S,5R)-4-Hydroxy-5-((E)-3-hydroxy-4-phenyl-but-1-enyl)-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid methyl ester (48, 49)
    (Z)-7-[(1R,4S,5R)-4-Hydroxy-5-((E)-3-hydroxy-5-phenyl-pent-1-enyl)-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid methyl ester (50,51)
    (Z)-7-[(1R,4S,5R)-4-Hydroxy-5-((E)-3-hydroxy-5-phenyl-pent-1-enyl)-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid (52,53)
    (Z)-7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid (54,55)
    7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-heptanoic acid (56,57)
    (Z)-7-[(1R,4S,5R)-5-(4-Benzo[b]thiophen-2-yl-3-hydroxy-butyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid (58,59)
    (Z)-7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid ethylamide (60,61)
    (Z)-7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid diethylamide (62,63)
    (Z)-7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid (2-hydroxy-ethyl)amide (64,65)
    S,4R,5R)-4-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-3-hydroxy-2,2-dimethyl-5-[(Z)-6-(1-H-tetrazol-5-yl)-hex-2-enyl]-cyclopentanone (66,67)
    (Z)-7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid amide (68,69)
    (Z)-7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid methyl ester (70,71)
    7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-ynoic acid methyl ester (72,73)
    7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-ynoic acid (74,75)


Pharmaceutical compositions may be prepared by combining a therapeutically effective amount of at least one compound according to the present invention, or a pharmaceutically acceptable acid addition salt thereof, as an active ingredient, with conventional ophthalmically acceptable pharmaceutical excipients, and by preparation of unit dosage forms suitable for topical ocular use. The therapeutically efficient amount typically is between about 0.0001 and about 5% (w/v), preferably about 0.001 to about 1.0% (w/v) in liquid formulations.
For ophthalmic application, preferably solutions are prepared using a physiological saline solution as a major vehicle. The pH of such ophthalmic solutions should preferably be maintained between 6.5 and 7.2 with an appropriate buffer system. The formulations may also contain conventional, pharmaceutically acceptable preservatives, stabilizers and surfactants.
Preferred preservatives that may be used in the pharmaceutical compositions of the present invention include, but are not limited to, benzalkonium chloride, chlorobutanol, thimerosal, phenylmercuric acetate and phenylmercuric nitrate. A preferred surfactant is, for example, Tween 80. Likewise, various preferred vehicles may be used in the ophthalmic preparations of the present invention. These vehicles include, but are not limited to, polyvinyl alcohol, povidone, hydroxypropyl methyl cellulose, poloxamers, carboxymethyl cellulose, hydroxyethyl cellulose and purified water.
Tonicity adjustors may be added as needed or convenient. They include, but are not limited to, salts, particularly sodium chloride, potassium chloride, mannitol and glycerin, or any other suitable ophthalmically acceptable tonicity adjustor.
Various buffers and means for adjusting pH may be used so long as the resulting preparation is ophthalmically acceptable. Accordingly, buffers include acetate buffers, citrate buffers, phosphate buffers and borate buffers. Acids or bases may be used to adjust the pH of these formulations as needed.
In a similar vein, an ophthalmically acceptable antioxidant for use in the present invention includes, but is not limited to, sodium metabisulfite, sodium thiosulfate, acetylcysteine, butylated hydroxyanisole and butylated hydroxytoluene.
Other excipient components which may be included in the ophthalmic preparations are chelating agents. The preferred chelating agent is edentate disodium, although other chelating agents may also be used in place or in conjunction with it.
The ingredients are usually used in the following amounts:













Ingredient
Amount (% w/v)








active ingredient
about 0.001-5



preservative
0-0.10



vehicle
0-40



tonicity adjustor
1-10



buffer
0.01-10



pH adjustor
q.s. pH




4.5-7.5



antioxidant
as needed



surfactant
as needed



purified water
as needed to make 100%









The actual dose of the active compounds of the present invention depends on the specific compound, and on the condition to be treated; the selection of the appropriate dose is well within the knowledge of the skilled artisan.
The ophthalmic formulations of the present invention are conveniently packaged in forms suitable for metered application, such as in containers equipped with a dropper, to facilitate the application to the eye. Containers suitable for dropwise application are usually made of suitable inert, non-toxic plastic material, and generally contain between about 0.5 and about 15 ml solution.
SYNTHETIC EXAMPLES
The methods of preparing compounds of this invention are further illustrated by the following non-limiting Examples, which are summarized in the reaction schemes of FIGS. 1-7 wherein the compounds are identified by the same designator in both the Examples and the Figures.
2-Alkyl-cyclopentane-1,3-dione (1a). A mixture of 1,3-cyclopentanedione (89.4 mmol, Aldrich), I—R2 (96.4 mmol, Aldrich), and KOH (5.097 g, 90.8 mmol) in H2O (25 mL)/dioxane (75 mL) is heated at reflux. After 5 h, a solution of KOH (2 g) and I—R2 (2 mmol) in H2O (5 μL)/dioxane (15 mL) is added and after another 3 h at reflux the solution is allowed to stir at room temperature overnight. In the morning, the reaction is continued by addition of a solution of KOH (2 g) and I—R2 (2.4 mmol) in H2O (5 mL)/dioxane (15 mL) and heating at reflux. After 4 h, the mixture is allowed to cool to room temperature and is extracted with ether (1×100 mL, 3×75 mL). The combined ether extracts are evaporated, the residue is combined with HCl (50 mL 10%), and the resulting mixture is placed in a 120° C. oil bath until boiling is observed (ca. 15 min.). The mixture is then allowed to cool to room temperature, is neutralized by addition of NaHCO3 solution (150 mL, saturated) and the resulting mixture is then extracted with CH2Cl2 (4×75 mL). The combined CH2Cl2 solution is dried (MgSO4), filtered and evaporated to leave a brown oil which is used directly in the next step.
2-Alkyl-2-methyl-cyclopentane-1,3-dione (2a). A mixture of 2-methyl-1,3-cyclopentanedione (10.025 g, 89.4 mmol, Aldrich), I—R2 (96.4 mmol, Aldrich), and KOH (5.097 g, 90.8 mmol) in H2O (25 mL)/dioxane (75 mL) is heated at reflux. After 5 h, a solution of KOH (2 g) and I—R2 (2 mmol) in H2O (5 mL)/dioxane (15 mL) is added and after another 3 h at reflux the solution is allowed to stir at room temperature overnight. In the morning, the reaction is continued by addition of a solution of KOH (2 g) and I—R2 (2.4 mmol) in H2O (5 mL)/dioxane (15 mL) and heating at reflux. After 4 h, the mixture is allowed to cool to room temperature and is extracted with ether (1×100 mL, 3×75 mL). The combined ether extracts are evaporated, the residue is combined with HCl (50 mL 10%), and the resulting mixture is placed in a 120° C. oil bath until boiling is observed (ca. 15 min.). The mixture is then allowed to cool to room temperature, is neutralized by addition of NaHCO3 solution (150 mL, saturated) and the resulting mixture is then extracted with CH2Cl2 (4×75 mL). The combined CH2Cl2 solution is dried (MgSO4), filtered and evaporated to leave a brown oil which is used directly in the next step.
2,2-Dialkyl-methyl-cyclopentane-1,3-dione (2b). A mixture of 2-alkyl-1,3-cyclopentanedione 1a (89.4 mmol, Aldrich), I—R3 (96.4 mmol, Aldrich), and KOH (5.097 g, 90.8 mmol) in H2O (25 mL)/dioxane (75 mL) is heated at reflux. After 5 h, a solution of KOH (2 g) and I—R3 (2 mmol) in H2O (5 mL)/dioxane (15 mL) is added and after another 3 h at reflux the solution is allowed to stir at room temperature overnight. In the morning, the reaction is continued by addition of a solution of KOH (2 g) and I—R3 (2.4 mmol) in H2O (5 mL)/dioxane (15 μL) and heating at reflux. After 4 h, the mixture is allowed to cool to room temperature and is extracted with ether (1×100 mL, 3×75 mL). The combined ether extracts are evaporated, the residue is combined with HCl (50 mL 10%), and the resulting mixture is placed in a 120° C. oil bath until boiling is observed (ca. 15 min.). The mixture is then allowed to cool to room temperature, is neutralized by addition of NaHCO3 solution (150 mL, saturated) and the resulting mixture is then extracted with CH2Cl2 (4×75 mL). The combined CH2Cl2 solution is dried (MgSO4), filtered and evaporated to leave a brown oil which is used directly in the next step.
Spiro[2.4]heptane-4,7-dione (2c). A mixture of 2-alkyl-1,3-cyclopentanedione 1a (89.4 mmol, Aldrich), 1,2-dibromoethane (120 mmol, Aldrich), and KOH (5.097 g, 90.8 mmol) in H2O (25 mL)/dioxane (75 mL) is heated at reflux for 24 hours. The mixture is allowed to cool, and the crude product is extracted with ether (1×100 mL, 3×75 mL). The combined ether extracts are evaporated, the residue is combined with HCl (50 mL 10%), and the resulting mixture is placed in a 120° C. oil bath until boiling is observed (ca. 15 min.). The mixture is then allowed to cool to room temperature, is neutralized by addition of NaHCO3 solution (150 mL, saturated) and the resulting mixture is then extracted with CH2Cl2 (4×75 mL). The combined CH2Cl2 solution is dried (MgSO4), filtered and evaporated to leave a brown oil which is used directly in the next step.
2,2-Dimethyl-cyclopentane-1,3-dione (2). The published procedure was followed. (Agosta, W. C.; Smith, A. B. J. Org. Chem. 1970, 35, 3856) A mixture of 2-methyl-1,3-cyclopentanedione (10.025 g, 89.4 mmol, Aldrich), methyl iodide (6.0 mL, 96.4 mmol, Aldrich), and KOH (5.097 g, 90.8 mmol) in H2O (25 mL)/dioxane (75 mL) was heated at reflux. After 5 h, a solution of KOH (2 g) and MeI (2.4 mL) in H2O (5 mL)/dioxane (15 mL) was added and after another 3 h at reflux the solution was allowed to stir at room temperature overnight. In the morning, the reaction was continued by addition of a solution of KOH (2 g) and MeI (2.4 mL) in H2O (5 mL)/dioxane (15 mL) and heating at reflux. After 4 h, the mixture was allowed to cool to room temperature and was extracted with ether (1×100 mL, 3×75 mL). The combined ether extracts were evaporated, the residue combined with HCl (50 mL 10%), and the resulting mixture was placed in a 120° C. oil bath until boiling was observed (ca. 15 min.). The mixture was then allowed to cool to room temperature, was neutralized by addition of NaHCO3 solution (150 mL, saturated) and the resulting mixture then extracted with CH2Cl2 (4×75 mL). The combined CH2Cl2 solution was dried (MgSO4), filtered and evaporated to leave a brown oil (10.474 g, 83 mmol, 93%) which was used directly in the next step. (S)-3-Hydroxy-2,2-dimethyl-cyclopentanone (3). The published procedure was followed. (Brooks, D. W.; Hormoz, M.; Grothaus, P. G. J. Org. Chem. 1987, 52, 3223) A 35° C. (internal temperature) solution of D-glucose (106.73 g, 592 mmol, Aldrich) in H2O (690 mL) in a 4 L Erlenmeyer was treated with baker's yeast (71.065 g, Fleischmann's). The mixture was allowed to ferment for 2 h, then 2,2-dimethyl-cyclopentane-1,3-dione (2) (7.316 g, 58 mmol) was added.
The mixture was stirred for 48 h and then filtered through celite, washing with about 1 L CH2Cl2. The filtration was difficult due to the thick consistency of the yeast and it helped to continually add CH2Cl2 to the mixture and scrape the top of the celite layer with a spatula. The filtrate was transferred to a separatory funnel, and 100 mL brine was added and the layers were separated. Brine (400 mL) was added to the aqueous layer and the resulting solution extracted further with CH2Cl2 (3×500 mL). The combined CH2Cl2 solution was dried (MgSO4), filtered and evaporated to leave a yellow oil. Flash chromatography (11×5 cm, 20% EtOAc/hexs→25%→30%→40%→50%) gave alcohol 3 (2.435 g, 19 mmol, 33%).
The enantiomeric excess of 3 was assayed by 1H NMR of the corresponding Mosher's ester which was prepared by treatment of alcohol 3 (11 mg, 0.09 mmol) in dichloroethane (0.3 mL, Aldrich) with pyridine (27 μL, 0.33 mmol, Aldrich) and (R)-α-methoxy-α-trifluoromethyphenylacetic acid chloride (58 μL, 0.31 mmol, Fluka). The mixture was stirred overnight and then partitioned between water (10 mL) and ether (10 mL). The ether layer was washed with 1 M HCl (10 mL) and saturated NaHCO3 solution and then was dried (MgSO4), filtered and evaporated. 1H NMR analysis was done on the crude ester.
(S)-3-(tert)-Butyl-dimethyl-silanyloxy-2,2-dimethyl-cyclopentanone (4). A solution of alcohol 3 (520 mg, 4.1 mmol) and 2,6-lutidine (0.56 mL, 4.8 mmol, Aldrich) in CH2Cl2 (8.0 mL, Aldrich) was treated with TBSOTf (1.0 mL, 4.3 mmol, Aldrich). After 5.5 h, saturated NaHCO3 solution (20 mL) was added and the mixture extracted with CH2Cl2 (20 mL). The CH2Cl2 solution was washed with 20 mL each of 1 M HCl, saturated NaHCO3 solution, and brine and then was dried (MgSO4), filtered and evaporated. Flash chromatography (5×5 cm, 10% Et2O/pentane) gave TBS ether 4 (698 mg, 2.9 mmol, 70%).
(S)-3-(tert)-Butyl-dimethyl-silanyloxy-2,2-dimethyl-5-phenylselanyl-cyclopentanone (5). A solution of TBS ether 4 (1.496 g, 6.2 mmol) in THF (2 mL, Aldrich) was added dropwise to a −78° C. solution of LDA (4.9 mL, 7.3 mmol, 1.5 M/cyclohexane, Aldrich) in THF (22 mL, Aldrich), rinsing with 2 mL THF. After 15 min., a solution of PhSeCl (1.424 g, 7.4 mmol, Aldrich) in THF (2 mL) was quickly added by cannula, rinsing with 2 mL THF. The solution was stirred for 10 min. and then partitioned between 50 mL 0.5 M HCl and 75 mL ether. The ether layer was washed with 30 mL each of water, saturated NaHCO3 solution, and brine and then was dried (MgSO4), filtered and evaporated. Flash chromatography (2% EtOAc/hexs→4%) gave phenylselenide 5 (1.641 g, 4.1 mmol, 67%) along with 476 mg of mixed fractions containing a lower Rf impurity.
(S)-4-(tert)-Butyl-dimethyl-silanyloxy-5,5-dimethyl-cyclopent-2-enone (6). A solution of selenide 5 (1.641 g, 4.1 mmol) and pyridine (0.62 mL, 7.7 mmol, Aldrich) in CH2Cl2 (13 mL, Aldrich) was treated with H2O (1 mL) and 30% H2O2 (1.1 mL, Aldrich). The mixture was stirred for 30 min. and then was partitioned between 25 mL CH2Cl2 and 25 mL saturated NaHCO3 solution. The aqueous layer was extracted with 25 mL CH2Cl2 and the combined CH2Cl2 solution washed with 1 M HCl (2×25 mL) and brine (50 mL). The solution was then dried (MgSO4), filtered and evaporated to leave an orange oil. Flash chromatography (6×4 cm, 10% ether/pentane) gave enone 6 (572 mg, 2.4 mmol, 59%).
(3-Mercapto-propylsulfanyl)-acetic acid methyl ester (8). An ice-cold solution of 1,3-dithiane (2.0 mL, 19.9 mmol) in THF (40 mL) was treated with NaH (819 mg, 20.5 mmol). After 30 min., methyl bromoacetate (1.9 mL, 20.0 mmol) was added and the mixture stirred for 3.5 h at room temperature. The reaction was quenched by addition of MeOH and then 50 mL 1 M HCl. The mixture was extracted with ether (2×50 mL) and the combined ether solution washed with saturated sodium bicarbonate solution (50 mL) and brine (50 mL) and then was dried (MgSO4), filtered and evaporated. Purification by flash chromatography on silica gel (10-15% ethyl acetate/hexanes) gave 971 mg (5.38 mmol, 27%) of the thiol.
{3-[(S)-3-(tert)-Butyl-dimethyl-silanyloxy)-4,4-dimethyl-5-oxo-cyclopent-1-enylsulfanyl]-propylsulfanyl}-acetic acid methyl ester (10). A solution of enone 6 (156 mg, 0.65 mmol) in MeOH (4.3 mL) was treated with 30% H2O2 (0.21 mL) and 1 M NaOH (32 μL). After 4 h, 20 mL saturated ammonium chloride solution was added and the mixture was extracted with dichloromethane (3×10 mL). The combined dichloromethane solution was dried (Na2SO4), filtered and evaporated in vacuo.
A solution of thiol 8 (110 mg, 0.61 mmol) in dichloromethane (3 mL) was added to the crude epoxide (9) by cannula, rinsing with 1.2 mL. Basic alumina (628 mg) was added and the mixture stirred for 16 h. The solvent was evaporated and purification of the residue by flash chromatography on silica gel (15% ethyl acetate/hexanes) gave 129 mg (0.31 mmol, 48%) of the coupled enone (10).
(3-Chloro-benzo[b]thiophen-2-yl)-methanol (12). To an ice cold solution of 10.0 g (47.0 mmol) of 3-chloro-benzo[b]thiophene-2-carboxylic acid (11) in 200 mL of THF was added 47 mL of LiAlH4 (47 mmol, 1 M/THF). After 3 h, the reaction was quenched by addition of MeOH (ca. 40 mL). The volatiles were evaporated and the residue was treated with 50 mL 1 M HCl. After stirring for 10 min., the mixture was extracted with CH2Cl2 (3×150 mL). The combined CH2Cl2 solution was dried (MgSO4), filtered and evaporated. Purification by flash chromatography on silica gel (10-20% ethyl acetate/hexane) gave 4.32 g (21.6 mmol, 46%) of the alcohol (12).
3-Chloro-benzo[b]thiophene-2-carbaldehyde (13). A solution of alcohol 12 (4.32 g, 21.6 mmol) in 40 mL of CH2Cl2 was treated with 4A molecular sieves, NMO (3.81 g, 32.5 mmol), and TPAP (381 mg, 1.08 mmol). The reaction was stirred for 10 min. and then was evaporated to dryness. Purification by flash chromatography on silica gel (2% ethyl acetate/hexane) gave 3.52 g (18.3 mmol, 84%) of the aldehyde (13).
(E)-3-(3-Chloro-benzo[b]thiophen-2-yl)-acrylic acid methyl ester (14). A solution of 3.52 g (18.3 mmol) of 13 in 50 mL toluene was treated with methyl(triphenylphosphoranylidene)acetate (7.48 g, 21.9 mmol). After 4 h, saturated NaHCO3 solution (50 mL) was added and the mixture extracted with ethyl acetate (2×75 mL). The combined ethyl acetate solution was washed with brine (50 mL), dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (5% ethyl acetate/hexane) provided 3.60 g (14.6 mmol, 80%) of the enoate (14).
3-(3-Chloro-benzo[b]thiophen-2-yl)-propionic acid methyl ester (15). A solution of 3.60 g (14.6 mmol) of 14 in 50 mL THF was treated with Wilkinson's catalyst (3.35 g, 3.62 mmol). The mixture was stirred under 1 atm H2 for 18 h and then was filtered through celite. The solvent was evaporated and the residue purified by flash chromatography on silica gel (0-2% ethyl acetate/hexane) to give 3.63 g (14.3 mmol, 99%) of the saturated ester (15).
3-(3-Chloro-benzo[b]thiophen-2-yl)-propan-1-ol (16). An ice cold solution of 3.63 g (14.3 mmol) of 15 in 60 mL of ether was treated with LiBH4 (621 mg, 28.5 mmol) and methanol (2 mL). After 30 min., 30 mL of 0.5 M NaOH solution was added. The mixture was extracted with ethyl acetate (2×25 mL) and the combined ethyl acetate solution washed with brine (50 mL), dried (MgSO4), filtered and evaporated. The residue was purified by flash chromatography on silica gel (5-20% ethyl acetate/hexane) to give 2.57 g (11.3 mmol, 79%) of the alcohol (16).
3-(3-Chloro-benzo[b]thiophen-2-yl)-propionaldehyde (17). A −78° C. solution of oxalyl chloride (1.73 g, 13.6 mmol) in dichloromethane (20 mL) was treated with DMSO (20 mL). After 5 min., a solution of alcohol 16 (2.57 g, 11.3 mmol) in dichloromethane (20 mL) was added. After another 15 min., triethylamine (7.1 mL, 50.6 mmol) was added. The reaction was stirred at −78° C. for 5 min., and then allowed to warm to room temperature. After 30 min., 100 mL water was added and the mixture extracted with dichloromethane (3×60 mL). The combined dichloromethane solution was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (10% ethyl acetate/hexane) gave 2.11 g (9.4 mmol, 83%) of the aldehyde (17).
5-(3-Chloro-benzo[b]thiophen-2-yl)-pent-1-yn-3-ol (18). A solution of aldehyde 17 (2.11 g, 9.4 mmol) in 15 mL THF was added to a solution of ethynylmagnesium bromide (28.2 mL, 14.1 mmol, 0.5 M THF) at 0° C. After 1.5 h, saturated NH4Cl solution (75 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined ethyl acetate solution was washed with brine (50 mL) and then was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography (5-20% ethyl acetate/hexane) gave 2.20 g (8.78 mmol, 93%) of the alcohol (18).
tert-Butyl-{1-[2-(3-chloro-benzo[b]thiophen-2-yl)-ethyl]-prop-2-ynyloxy}-dimethyl-silane (19). A solution of alcohol 18 (2.20 g, 8.78 mmol) in dichloromethane (15 mL) was treated with DMAP (215 mg, 1.8 mmol), TBSCl (1.59 g, 10.5 mmol), and triethylamine (1.8 mL, 13.2 mmol). The reaction was stirred for 24 h and then saturated sodium bicarbonate solution (50 mL) was added. The mixture was extracted with dichloromethane (2×50 mL) and the combined dichloromethane solution dried (Na2SO4), filtered and evaporated. Purification by flash chromatography (4% ethyl acetate/hexane) gave 3.06 g (6.4 mmol, 73%) of the protected alcohol (19).
(3-{(1R,4S,5S)-4-(tert-Butyl-dimethyl-silanyloxy)-5-[(E)-3-(tert-butyl-dimethyl-silanyloxy)-5-(3-chloro-benzo[b]thiophen-2-yl)-pent-1-enyl]-3,3-dimethyl-2-oxo-cyclopentylsulfanyl}-propylsulfanyl)-acetic acid methyl ester (20). A solution of alkyne 19 (105 mg, 0.28 mmol) in THF (1.2 mL) was treated with bis(cyclopentadienyl)zirconium chloride hydride (91 mg, 0.35 mmol). The reaction was stirred for 30 min., then was cooled to −78° C. and treated with methyllithium (0.46 mL, 0.64 mmol, 1.4 M in ether). After 10 min., a precooled (−78° C.) solution of lithium 2-thienylcyanocuprate (1.3 mL, 0.33 mmol, 0.25 M in THF) was added by cannula. The reaction was stirred for 45 min. and then enone 10 (61 mg, 0.15 mmol) in 0.2 mL THF was added by cannula, rinsing with 0.2 nL THF. After 1 h, The reaction was quenched by addition of 20 mL 1:1 saturated ammonium chloride solution/concentrated ammonium hydroxide. The mixture was stirred for 45 min. and then was extracted with ethyl acetate (3×20 mL). The combined ethyl acetate solution was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (10% ethyl acetate/hexanes) gave 51 mg (0.064 mmol, 43%) of the coupled product (20).
(3-{(1R,4S,5S)-5-(3-chloro-benzo[b]thiophen-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentylsulfanyl}-propylsulfanyl)-acetic acid methyl ester (21, 22). A solution of 20 (51 mg, 0.064 mmol) in CH3CN (1.6 mL) was treated with HF-pyridine (0.26 mL). The reaction was stirred for 24 h and then was quenched by addition of 15 mL saturated sodium bicarbonate solution. The mixture was extracted with dichloromethane (3×10 mL) and the combined dichloromethane solution was dried (Na2SO4), filtered and evaporated. Purification by preparative thin layer chromatography on silica gel (40% ethyl acetate/hexanes) gave 12 mg (0.023 mmol, 71%) of each diastereomer.
(3-{(1R,4S,5S)-5-(3-chloro-benzo[b]thiophen-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentylsulfanyl}-propylsulfanyl)-acetic acid (23, 24). Rabbit liver esterase (9 mg) was added to a solution of the lower Rf ester 21 (11 mg, 0.021 mmol) in pH 7.2 phosphate buffer (0.5 mL)/CH3CN (0.1 mL). The mixture was stirred overnight and then 10 mL 0.5 M HCl was added along with a few mL's of brine. The mixture was extracted with ethyl acetate (3×10 mL) and the combined ethyl acetate solution dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (3-5% MeOH/CH2Cl2) gave 4 mg (0.0078 mmol, 37%) of the acid (23). 300 MHz 1H NMR (CDCl3, ppm) δ 7.73 (2H, d, J=8.4 Hz) 7.4-7.3 (2H, m) 5.9-5.8 (1H, m) 5.8-5.7 (1H, m) 4.4-4.3 (1H, m) 3.63 (1H, d, J=9.7 Hz) 3.21 (2H, s) 3.1-2.4 (11H, overlapping m) 2.1-1.7 (4H, overlapping m) 1.12 (3H, s) 1.03 (3H, s).
The higher Rf ester was hydrolyzed similarly except a solution of rabbit liver esterase (10 mg) in 0.5 mL of pH 7.2 phosphate buffer was added to a solution of the ester (10 mg, 0.019 mmol) in CH3CN (0.2 mL). The reaction was stirred for 22 h and then worked up and purified as above. This gave 7 mg (0.013 mmol, 71%) of the acid (24). 300 MHz 1H NMR (CDCl3, ppm) δ 7.73 (2H, d, J=8.8 Hz) 7.44-7.31 (2H, m) 5.9-5.8 (1H, m) 5.8-5.7 (1H, m) 4.4-4.3 (1H, m) 3.64 (1H, d, J=9.7 Hz) 3.3-2.3 (13H, overlapping m) 2.1-1.7 (4H, overlapping m) 1.12 (3H, s) 1.03 (3H, s).
tert-Butyl-hex-5-ynyloxy-dimethyl-silane (26).
7-(tert-Butyl-dimethyl-silanyloxy)-hept-2-yn-1-ol (27).
Acetic acid 7-(tert-butyl-dimethyl-silanyloxy)-hept-2-ynyl ester (28). A solution of 7-(tert-Butyl-dimethyl-silanyloxy)-hept-2-yn-1-ol 27 (4.507 g, 21 mmol) in pyridine (20 mL) was treated with acetic anhydride (3.0 mL, 31.8 mmol). After 18 h, the solvent was evaporated and the residue co-evaporated with toluene. The residue was used directly in the next step.
7-Acetoxy-hept-5-ynoic acid (29). A solution of crude 28 in acetone (100 mL) was treated with Jones Reagent (18.0 mL, 41.4 mmol, 2.3 M). The mixture became warm and so was cooled with an ice bath. After 1 h at room temperature, 10 mL isopropyl alcohol was added and the mixture stirred further for 15 min. The mixture still had a brown color so another 10 mL isopropyl alcohol was added. After another 15 min., the color had not changed so the mixture was filtered through celite and the filtrate evaporated in vacuo. The residue was partitioned between 100 mL ether and 100 mL saturated ammonium chloride solution. The aqueous layer was extracted with 100 mL ether and the combined ether solution washed with brine and then was dried (MgSO4), filtered and evaporated to leave a yellow oil (6.333 g) that was used directly in the next step.
7-Hydroxy-hept-5-ynoic acid methyl ester (30). The crude acid 29 (6.333 g) was treated with a 1% solution of acetyl chloride in methanol (60 mL). After 16 h, sodium bicarbonate (1.966 g, 23.4 mmol) was added. The mixture was dried (MgSO4), filtered through celite and evaporated in vacuo. Purification by flash chromatography on silica gel (30-40% ethyl acetate/hexanes) gave 7-Hydroxy-hept-5-ynoic acid methyl ester 30 (3.022 g, 19.3 mmol, 92% from 7-(tert-Butyl-dimethyl-silanyloxy)-hept-2-yn-1-ol 27).
7-Iodo-hept-5-ynoic acid methyl ester (31). A solution of 30 (1.347 g, 8.6 mmol) in 5 mL dichloromethane was added to a mixture of triphenylphosphine (2.725 g, 10.4 mmol), imidazole (726 mg, 10.7 mmol), and iodine (2.602 g, 10.3 mmol) in 34 mL dichloromethane, rinsing with 5 mL dichloromethane. After 40 min., the dichloromethane was evaporated in vacuo to a few mL's and the resulting mixture filtered through basic alumina, washing with 10% ethyl acetate/hexanes. Purification by flash chromatography on silica gel (10% ethyl acetate/hexanes) gave 1.878 g (7.1 mmol, 83%) of the propargyl iodide.
tert-Butyl-{(E)-1-[2-(3-chloro-benzo[b]thiophen-2-yl)-ethyl]-3-iodo-allyloxy}-dimethyl-silane (32). A solution of alkyne 19 (5.547 g, 15.2 mmol) in dichloromethane (50 mL) was treated with Cp2ZrHCl (5.794 g, 22.5 mmol). The reaction was stirred for 45 min. and then N-iodosuccinimide (4.966 g, 22.1 mmol) was added. After 15 min., saturated sodium bicarbonate solution (200 mL) was added and the mixture was extracted with dichloromethane (2×100 mL). The combined dichloromethane solution was dried (MgSO4), filtered and evaporated. Purification by flash chromatography on silica gel (0-5% ethyl acetate/hexanes) gave 6.608 g (13.1 mmol, 86%) of the vinyl iodide (32).
7-{(1R,4S,5R)-4-(tert-Butyl-dimethyl-silanyloxy)-5-[(E)-3-(tert-butyl-dimethyl-silanyloxy)-5-(3-chloro-benzo[b]thiophen-2-yl)-pent-1-enyl]-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-ynoic acid methyl ester (33). A −78° C. solution of iodide 32 (675 mg, 1.34 mmol) in THF (2.0 mL) was treated with tert-butyllithium (1.73 mL, 2.94 mL, 1.7 M/pentane). The dark red mixture was stirred for 25 min. and then dimethylzinc (0.80 mL, 1.6 mmol, 2 M/toluene) was added. The solution was stirred at 0° C. for 15 min. and then recooled to −78° C. At this time, a solution of enone 6 (208 mg, 0.87 mmol) in THF (1.0 mL) was added over 2 h by syringe pump, rinsing with 0.5 mL THF. After 30 min., HMPA (1.34 mL, distilled from CaH2) was added followed by a solution of propargyl iodide 31 (1.286 g, 4.83 mmol) in THF (1.0 mL). The solution was stirred in a −40° C. bath overnight and then 20 mL saturated ammonium chloride solution and 10 mL water were added. The mixture was extracted with dichloromethane (20 mL) and ethyl acetate (2×20 mL). The combined organic extracts were dried (MgSO4), filtered and evaporated. Purification by flash chromatography on silica gel (5-10% ethyl acetate/hexanes) gave 198 mg (0.27 mmol, 31%) of 33.
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-ynoic acid methyl ester (34,35). A solution of 33 (198 mg, 0.27 mmol) in CH3CN (6.5 mL) was treated with HF-pyridine (1.2 mL). The solution was stirred for 3 h and saturated sodium bicarbonate solution (120 mL) was added. The mixture was extracted with dichloromethane (3×50 mL) and the combined dichloromethane solution dried (Na2SO4), filtered and evaporated. Purification by flash chromatography (50% ethyl acetate/hexane) followed by preparative TLC (55% ethyl acetate/hexane) gave 55 mg (0.11 mmol, 41%) of the less polar diastereomer (34) and 51 mg (0.10 mmol, 37%) of the more polar diastereomer (35).
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-ynoic acid (low Rf diastereomer, 36). A solution of 34 (9 mg, 0.017 mmol) and rabbit liver esterase (1 mg) in pH 7.2 phosphate buffer (2 mL)/CH3CN (0.1 mL) was stirred for 17 h. The mixture was then coevaporated with CH3CN to remove water and the residue purified by flash chromatography on silica gel (3-7% MeOH/CH2Cl2) to give 8 mg (0.016 mmol, 93%) of the acid (36).
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-ynoic acid (high Rf diastereomer, 37). A solution of 35 (12 mg, 0.023 mmol) and rabbit liver esterase (1 mg) in pH 7.2 phosphate buffer (2 mL)/CH3CN (0.1 mL) was stirred for 17 h. TLC showed the presence of starting material, so another 2 mg of the esterase was added. After stirring for another 24 h, the reaction was complete. Work up and purification as above for 36 gave 8 mg (0.016 mmol, 69%) of the acid (37).
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-enoic acid methyl ester (low Rf diastereomer, 38). Ethanol (95%, 2.5 mL) was added to NiCl2 (50 mg, 0.39 mmol) and NaBH4 (7 mg, 0.19 mmol). The resulting black mixture was stirred for 5 min. and then ethylenediamine (41 μL, 0.61 mmol) was added. After 15 min., a solution of alkyne 34 (40 mg, 0.077 mmol) in 0.5 mL 95% ethanol was added, rinsing with 0.5 mL ethanol. The flask was purged with H2 and allowed to stir under 1 atm H2 for 22 h. The mixture was then filtered through celite and purified by flash chromatography on silica gel (55% ethyl acetate/hexanes) to give 17 mg (0.032 mmol, 43%) of the alkene (38).
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-enoic acid methyl ester (high Rf diastereomer 39). The same procedure as for 36 was followed to give 17 mg (0.032 mmol, 41%) of 39.
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-enoic acid (low Rf diastereomer, 40). The same procedure as above for 36 was used to give 9 mg (0.018 mmol, 85%) of acid 40. 300 MHz 1H NMR (CDCl3, ppm) δ 7.73 (2H, d, J=8.4 Hz) 7.45-7.30 (2H, m) 5.8-5.6 (2H, m) 5.4-5.3 (2H, m) 4.3-4.1 (1H, m) 3.57 (1H, d, J=9.7 Hz) 3.1-2.9 (2H, m) 2.5-1.9 (10H, m) 1.7-1.6 (2H, m) 1.09 (3H, s) 0.89 (3H, s).
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-enoic acid (high Rf diastereomer, 41). The same procedure as above for the 36 was used to give 9 mg (0.018 mmol, 85%) of acid 41. 300 MHz 1H NMR (CDCl3, ppm) □ 7.73 (2H, d, J=8.8 Hz) 7.45-7.30 (2H, m) 5.8-5.6 (2H, m) 5.45-5.30 (2H, m) 4.3-4.2 (1H, m) 3.61 (H, d, J=9.7 Hz) 3.1-3.0 (2H, m) 2.5-1.9 (10H, m) 1.7-1.6 (2H, m) 1.10 (3H, s) 0.90 (3H, s).
2-Benzo[b]thiophen-2-yl-ethanol (9-2, FIG. 9). n-BuLi (100 mL, 160 mmol, 1.6M/hexanes) was added to a −78° C. mixture of thianaphthene (17.31 g, 129 mmol) in THF (70 mL)/ether (30 mL). The mixture was stirred at −78° C. for 2 h and then a solution of ethylene oxide (42.86 g, 1,071 mmol) in THF (70 mL)/ether (30 mL) was added by cannula over 15 min. The resulting mixture was stirred for 2 h at −78° C. and then at room temperature for 15 h. At this time, the mixture was evaporated, 200 mL H2O was added, and the resulting mixture was extracted with ethyl acetate (3×150 mL). The combined organic solution was washed with brine and then was dried (Na2SO4), filtered, and evaporated. Purificaion by flash chromatography on silica gel (20% ethyl acetate/hexanes) gave 8-2 (13.61 g, 78 mmol, 60%).
Benzo[b]thiophen-2-yl-acetaldehyde (9-3). A 0° C. mixture of 9-2 (8.019 g, 44.9 mmol) in 100 mL dichloromethane was treated with Dess-Martin reagent (20 g, 47.2 mmol). The mixture was stirred at 0° C. for 10 min. and at room temperature for 40 min. Saturated NaHCO3 solution (200 mL) and 0.1 M NaHSO3 solution were added and the resulting mixture was extracted with ethyl acetate (3×300 mL). The combined organic solution was dried (Na2SO4), filtered and evaporated to give 9-3 (8.77 g). The aldehyde was taken on crude for the next reaction.
1-Benzo[b]thiophen-2-yl-but-3-yn-2-ol (9-4). A solution of crude 9-3 (8.77 g) in THF (100 mL) was added to a solution of ethynylmagnesium bromide (450 mL, 225 mmol, 0.5 M/THF) at 0° C. by cannula. The mixture was stirred for 1 h at 0° C. and for 1 h at room temperature. The reaction was then queched by addition of 200 mL saturated NH4Cl solution. The layers were separated and the aqueous layer was extracted with ethyl acetate (3×200 mL). The combined organic solution was washed with brine and then was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (10%→20% ethyl acetate/hexanes) gave 8-4 (7.67 g, 37.9 mmol, 84% from 9-2).
(1-Benzo[b]thiophen-2-ylmethyl-prop-2-ynyloxy)-tert-butyl-dimethyl-silane (9-5). DMAP (2.306 g, 18.9 mmol), TBSCl (11.502 g, 76.3 mmol) and triethylamine (5.25 mL, 37.7 mmol) were added to a solution of 9-4 (7.67 g, 37.9 mmol) in dichloromethane (120 mL). After 17 h, 150 mL of saturated NH4Cl solution was added and the layers were separated. The aqueous layer was extracted with dichloromethane (3×100 mL) and the combined organic solution was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (4% ethyl acetate/hexanes) gave 9-5 (8.38 g, 26.5 mmol, 70%).
((E)-1-Benzo[b]thiophen-2-ylmethyl-3-iodo-allyloxy)-tert-butyl-dimethyl-silane (9-6). Cp2ZrHCl (1.719 g, 6.67 mmol) was added to a solution of 9-5 (1.372 g, 4.34 mmol) in dichloromethane (30 mL). The reaction was stirred for 30 min. at room temperature and N-iodosuccinimide (1.997 g, 8.88 mmol) was added. After 1 h, the reaction was poured into 100 mL of saturated NaHCO3 solution. The resulting mixture was extracted with dichloromethane (3×75 mL) and the combined organic extracts were dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (2% ethyl acetate/hexanes) gave 9-6 (1.7484 g, 91%).
(Z)-7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid (2-hydroxy-ethyl)-amide (65)—General procedure for synthesis of secondary and tertiary amides. A solution of acid 55 (7 mg, 0.015 mmol) in DMF (0.5 mL) was treated with N-hydroxysuccinimide (6.9 mg, 0.056 mmol). The mixture was stirred for 5 minutes and 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDCI, 20.7 mg, 0.11 mmol) was added. After stirring for 7 h, 2-aminoethanol (5 □L, 0.083 mmol) was added and the mixture stirred further for 16 h. Ethyl acetate (50 mL) was added and the mixture was washed with water (3×50 mL) and brine (50 mL). The organic layer was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (5% methanol/dichloromethane) followed by preparative thin layer chromatography (10% methanol/dichloromethane) gave amide 65 (5 mg, 0.010 mmol, 65%). Amides 60-63 were prepared in a similar manner.
(Z)-7-[(1R,4S,5R)-5-((E)-4-Benzo[b]thiophen-2-yl-3-hydroxy-but-1-enyl)-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl]-hept-5-enoic acid amide (69). A solution of acid 55 (9 mg, 0.02 mmol) in dichloromethane (0.2 mL) was treated with triethylamine (15 □L, 0.11 mmol). The solution was cooled to 0° C. and after 10 minutes, ethyl chloroformate (7 □L, 0.073 mmol) was added. The solution was stirred further for 1 h at 0° C. and then concentrated aqueous ammonium hydroxide solution was added (10 □L, 0.26 mmol). The reaction was allowed to stir at room temperature overnight and then was quenched by addition of 0.5 M HCl (7 mL). The mixture was extracted with ethyl acetate (3×30 mL) and the combined ethyl acetate solution was washed with saturated NaHCO3 solution (20 mL) and brine (20 mL) and then was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (2%-6% methanol/dichloromethane) gave the title amide (2.6 mg, 28%).
The methods of screening the compounds of this invention for the desired biological activity are illustrated in the following non-limiting examples. Results for example compounds of this invention are included in Table 2. These results are presented purely for illustrative purposes and are not intended to limit the scope of the invention in any way.
Radioligand Binding
Cells Stably Expressing EP1, EP2, EP3, EP4 and FP Receptors
HEK-293 cells stably expressing the human or feline FP receptor, or EP1, EP2, EP3, or EP4 receptors were washed with TME buffer, scraped from the bottom of the flasks, and homogenized for 30 sec using a Brinkman PT 10/35 polytron. TME buffer was added to achieve a final 40 ml volume in the centrifuge tubes (the composition of TME is 100 mM TRIS base, 20 mM MgCl2, 2M EDTA; 10 N HCl is added to achieve a pH of 7.4).
The cell homogenate was centrifuged at 19000 r.p.m. for 20 min at 4° C. using a Beckman Ti-60 rotor. The resultant pellet was resuspended in TME buffer to give a final 1 mg/ml protein concentration, as determined by Biorad assay. Radioligand binding competition assays vs. [3H-]17-phenyl PGF2α (5 nM) were performed in a 100 μl volume for 60 min. Binding reactions were started by adding plasma membrane fraction. The reaction was terminated by the addition of 4 ml ice-cold TRIS-HCl buffer and rapid filtration through glass fiber GF/B filters using a Brandel cell harvester. The filters were washed 3 times with ice-cold buffer and oven dried for one hour. Non-specific binding was determined with 10 uM unlabeled 17-phenyl PGF2α.
[3H-] PGE2 (5 nM; specific activity 180 Ci mmol) was used as the radioligand for EP receptors. Binding studies employing EP1, EP2, EP3, EP4 were performed in duplicate in at least three separate experiments. A 200 μl assay volume was used. Incubations were for 60 min at 25° C. and were terminated by the addition of 4 ml of ice-cold 50 mM TRIS-HCl, followed by rapid filtration through Whatman GF/B filters and three additional 4 ml washes in a cell harvester (Brandel). Non-specific binding determined with 10−5M of unlabeled PGE2.
Methods for FLIPRTM Studies
(a) Cell Culture
HEK-293 (EBNA) cells, stably expressing one type or subtype of recombinant human prostaglandin receptors (prostaglandin receptors expressed: hDP/Gqs5; hEP1; hEP2/Gqs5; hEP3A/Gqi5; hEP4/Gqs5; hFP; hIP; hTP), were cultured in 100 mm culture dishes in high-glucose DMEM medium containing 10% fetal bovine serum, 2 mM 1-glutamine, 250 μg/ml geneticin (G418) and 200 μg/ml hygromycin B as selection markers, and 100 units/ml penicillin G, 100 μg/ml streptomycin and 0.25 μg/ml amphotericin B.
(b) Calcium Signal Studies on the FLIPRTM
Cells were seeded at a density of 5×104 cells per well in Biocoat® Poly-D-lysine-coated black-wall, clear-bottom 96-well plates (Becton-Dickinson) and allowed to attach overnight in an incubator at 37° C. Cells were then washed two times with HBSS-HEPES buffer (Hanks Balanced Salt Solution without bicarbonate and phenol red, 20 mM HEPES, pH 7.4) using a Denley Cellwash plate washer (Labsystems). After 45 minutes of dye-loading in the dark, using the calcium-sensitive dye Fluo-4 AM at a final concentration of 2 μM, plates were washed four times with HBSS-HEPES buffer to remove excess dye leaving 100 μl in each well. Plates were re-equilibrated to 37° C. for a few minutes.
Cells were excited with an Argon laser at 488 nm, and emission was measured through a 510-570 nm bandwidth emission filter (FLIPRTM, Molecular Devices, Sunnyvale, Calif.). Drug solution was added in a 50 □l volume to each well to give the desired final concentration. The peak increase in fluorescence intensity was recorded for each well. On each plate, four wells each served as negative (HBSS-HEPES buffer) and positive controls (standard agonists: BW245C (hDP); PGE2 (hEP1; hEP2/Gqs5; hEP3A/Gqi5; hEP4/Gqs5); PGF2□ (hFP); carbacyclin (hIP); U-46619 (hTP), depending on receptor). The peak fluorescence change in each drug-containing well was then expressed relative to the controls.
Compounds were tested in a high-throughput (HTS) or concentration-response (CoRe) format. In the HTS format, forty-four compounds per plate were examined in duplicates at a concentration of 10−5 M. To generate concentration-response curves, four compounds per plate were tested in duplicates in a concentration range between 10−5 and 10−11 M. The duplicate values were averaged. In either, HTS or CoRe format each compound was tested on at least 3 separate plates using cells from different passages to give an n≧3.















TABLE 2





Com-



hEP3D






pound
hFP
hEP1
hEP2
hEP3A
hEP4
hDP
hIP
hTP







21
NA
NA
>10K
NA
  98
NA
NA
NA


22


NA
NA
 300



NA
NA
NA
NA
  30
NA
NA
NA


23


NA
>10K
  44



NA
NA
NA
NA
  0.1
NA
NA
>10K


24


NA
>>10K
  26



NA
NA
NA
NA
  0.1
NA
NA
NA


34


NA

>10K



NA


NA
>10K

NA
NA


35
NA


NA
 2455

NA
NA


36


NA

 200



NA


NA
  66

>10K
NA


37


NA

 100



NA


NA
  32

>10K
NA


38


NA

 2700



NA


NA
 269

NA
NA


39


NA

 2300



NA


NA
 141

NA
NA


40


NA

 200



NA


NA
  0.3

NA
>10K


41
NA

>10K
NA
  20

NA
>10K


42


NA
 >104
 >104



NA
NA
NA
 559
NA
NA
NA
NA


43


NA
1700
 400



NA
 >104
NA
 11
  63

3981
 18


44


1500
 300
  5.5



NA
 782
 944
  4.6
  0.2
>10K
 284
 18


45


NA
 >104
 400

NA
631



NA
NA
NA
 531
  51
NA
NA
NA


46


>10K
>10K
  4



NA
 290

 589
  0.4
NA
NA


47
NA
 963
NA
>10K
  76

NA


48


NA

  45


49


NA

 1400


50


NA
6607
 2400



NA
 638

>10K
 3162

NA
>10K


51
NA

NA
NA
 700

NA


52


NA

  72



NA
 27

 60
  18

NA


53




  59



NA
1020
NA
1862
  6.4

NA


54


NA
4700
  20



NA
 308
NA

  0.3
NA
NA


55


NA
>10K
 310



NA
 758
NA

  38
NA
NA


60
NA
NA
NA
NA
>10K
NA
NA
NA


61
NA
NA
NA
NA
NA
NA
NA
NA


62
NA
NA
NA
NA
 832
NA
NA
NA


63
NA
>10K
NA
NA
 478
NA
NA
NA


64
NA
NA
NA
NA
 4154
NA
NA
NA


65
NA
NA
NA
NA
NA
NA
NA
NA


68
NA
NA
NA
NA
 678
NA
NA
>10K


69
NA
NA
NA
NA
 5000
NA
NA
>10K


70
NA
NA
NA
>10K
 219
NA
NA


71
NA
NA
NA
NA
10000
NA
NA


72
NA
NA
NA
NA
>10K
NA
NA
NA


73
NA
NA
NA
NA
NA
NA
NA
NA


74
NA
2376
NA

 256
NA
NA


75
NA
2050
NA

>10K
NA
NA
>10K





The top numbers are the radioligand binding IC50 values(nM)


The bottom numbers are the functional EC50 data (nM)






While not intending to limit the scope of the invention in any way, the results presented in Table 2 suggest that the compounds described herein are selective EP4 agonists, and will thus be useful for the treatment of inflammatory bowel disease.
The compounds disclosed herein are also useful in combination with other drugs useful for the treatment of glaucoma or other conditions. For the treatment of glaucoma, combination treatment with the following classes of drugs are contemplated:
β-Blockers (or β-adrenergic antagonists) including carteolol, levobunolol, metiparanolol, timolol hemihydrate, timolol maleate, β1-selective antagonists such as betaxolol, and the like, or pharmaceutically acceptable salts or prodrugs thereof;
Adrenergic Agonists including
non-selective adrenergic agonists such as epinephrine borate, epinephrine hydrochloride, and dipivefrin, and the like, or pharmaceutically acceptable salts or prodrugs thereof; and
α2-selective adrenergic agonists such as apraclonidine, brimonidine, and the like, or pharmaceutically acceptable salts or prodrugs thereof;
Carbonic Anhydrase Inhibitors including acetazolamide, dichlorphenamide, methazolamide, brinzolamide, dorzolamide, and the like, or pharmaceutically acceptable salts or prodrugs thereof;
Cholinergic Agonists including
direct acting cholinergic agonists such as carbachol, pilocarpine hydrochloride, pilocarbine nitrate, pilocarpine, and the like, or pharmaceutically acceptable salts or prodrugs thereof; chlolinesterase inhibitors such as demecarium, echothiophate, physostigmine, and the like, or pharmaceutically acceptable salts or prodrugs thereof;

Glutamate Antagonists and other neuroprotective agents such as Ca2+ channel blockers such as memantine, amantadine, rimantadine, nitroglycerin, dextrophan, detromethorphan, CGS-19755, dihydropyridines, verapamil, emopamil, benzothiazepines, bepridil, diphenylbutylpiperidines, diphenylpiperazines, HOE 166 and related drugs, fluspirilene, eliprodil, ifenprodil, CP-101,606, tibalosine, 2309BT, and 840S, flunarizine, nicardipine, nifedimpine, nimodipine, barnidipine, verapamil, lidoflazine, prenylamine lactate, amiloride, and the like, or pharmaceutically acceptable salts or prodrugs thereof;

Prostamides such as bimatoprost, or pharmaceutically acceptable salts or prodrugs thereof; and

Prostaglandins including travoprost, UFO-21, chloprostenol, fluprostenol, 13,14-dihydro-chloprostenol, isopropyl unoprostone, latanoprost and the like.

Cannabinoids including CB1 agonists such as WIN-55212-2 and CP-55940 and the like, or pharmaceutically acceptable salts or prodrugs thereof.

For treatment of diseases affecting the eye including glaucoma, these compounds can be administered topically, periocularly, intraocularly, or by any other effective means known in the art.

The foregoing description details specific methods and compositions that can be employed to practice the present invention, and represents the best mode contemplated. However, it is apparent for one of ordinary skill in the art that further compounds with the desired pharmacological properties can be prepared in an analogous manner, and that the disclosed compounds can also be obtained from different starting compounds via different chemical reactions. Similarly, different pharmaceutical compositions may be prepared and used with substantially the same result. Thus, however detailed the foregoing may appear in text, it should not be construed as limiting the overall scope hereof; rather, the ambit of the present invention is to be governed only by the lawful construction of the appended claims.

## Claims

1. A method comprising administering a compound to a mammal suffering from an inflammatory bowel disease for the treatment of said disease, said compound having a structure according to



wherein the hatched wedges indicate the α (down) configuration, and the solid triangle indicates the β (up) configuration;
B is a single, double, or triple covalent bond;
Y is any pharmaceutically acceptable salt of CO2H, or CO2R,
R is methyl.

2. A method comprising administering a compound to a mammal suffering from inflammatory bowel disease for the treatment of said disease, said compound having a structure according to Formula IV



wherein Y is CO2R, wherein R is Me or any pharmaceutically acceptable salt of CO2H; and
R6 is 3 chlorobenzothien-2-yl or phenyl.

3. The method of claim 2 wherein B is a double bond.

4. The method of claim 2 wherein R6 is 3-chlorobenzothien-2-yl.

5. The method of claim 4 wherein B is a double or triple bond.

6. The method of either claim 1 or claim 2 wherein said compound is selected from the group consisting of
(3-{(1R,4S,5S)-5-(3-chloro-benzo[b]thiophen-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentylsulfanyl}-propylsulfanyl)-acetic acid methyl ester;
(3-{(1R,4S,5S)-5-(3-chloro-benzo[b]thiophen-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentylsulfanyl}-propylsulfanyl)-acetic acid;
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-ynoic acid methyl ester;
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-ynoic acid;
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-enoic acid methyl ester;
(Z)-7-{(1R,4S,5R)-5-[(E)-5-(3-chloro-benzo[b]thiophene-2-yl)-3-hydroxy-pent-1-enyl]-4-hydroxy-3,3-dimethyl-2-oxo-cyclopentyl}-hept-5-enoic acid.