# Patent

## Title
Therapeutic fluoroethylcyano guanidines

## Abstract

Disclosed herein is compound having a formula




as described herein. Therapeutic methods, compositions, and medicaments related thereto are also disclosed.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application Ser. No. 60/911,478 filed Apr. 12, 2007, which is hereby incorporated by reference in its entirety.


DESCRIPTION OF THE INVENTION
There is an ongoing need for compounds that are useful for treating pain.
The compounds disclosed herein are useful to treat chronic pain, allodynia, muscle spasticity, diarrhea, neuropathic pain, and/or visceral pain.
These compounds are generally described by the formula




wherein a dashed line indicates the presence or absence of a bond;
n is 0 or 1;
A is substituted or unsubstituted phenyl;
B is alkyl having 1, 2, 3, or 4 carbon atoms; or
B is H or substituted or unsubstituted phenyl and the dashed line is not a covalent bond.
Unless otherwise indicated, reference to a compound should be construed broadly to include pharmaceutically acceptable salts, and tautomers of the depicted structure. For example, the structures herein are intended to include, but are not limited to, the tautomeric forms shown below.




A “pharmaceutically acceptable salt” is any salt that retains the activity of the parent compound and does not additional unacceptable deleterious or untoward effects on the subject to which it is administered and in the context in which it is administered compared to the parent compound. A pharmaceutically acceptable salt also refers to any salt which may form in vivo as a result of administration of an acid, another salt, or a prodrug which is converted into an acid or salt.
Pharmaceutically acceptable salts of acidic functional groups may be derived from organic or inorganic bases. The salt may comprise a mono or polyvalent ion. Of particular interest are the inorganic ions, lithium, sodium, potassium, calcium, and magnesium. Organic salts may be made with amines, particularly ammonium salts such as mono-, di- and trialkyl amines or ethanol amines. Salts may also be formed with caffeine, tromethamine and similar molecules. Hydrochloric acid or some other pharmaceutically acceptable acid may form a salt with a compound that includes a basic group, such as an amine or a pyridine ring.
Unless stereochemistry is explicitly depicted, a structure is intended to include every possible stereoisomer, both pure or in any possible mixture.
Since a dashed line indicates the presence or absence of a bond, compounds according to the structures below are possible.




Because n is 0 or 1, compounds according to any of the structures below are possible.




A is substituted or unsubstituted phenyl.
Substituted phenyl may have 1, 2, 3, 4, or 5 substituents. The substituents have from 0 to 6 carbon atoms, from 0 to 3 oxygen atoms, from 0 to 2 sulfur atoms, from 0 to 1 nitrogen atoms, from 0 to 3 fluorine atoms, 0 or 1 chlorine atom, 0 or 1 bromine atom, and 0 or 1 iodine atoms. Two substituents may form a ring such that if the dashed line in the general structure is not a covalent bond, phenyl is part of a bicyclic system, or if the dashed line in the general structure is a covalent bond, phenyl is part of a tricyclic ring system.
For example, the core structures shown below are possible, wherein the ring system may have additional substituents subject to the constraints defined herein.




Examples of substituents include, but are not limited to:
Hydrocarbyl having from 1 to 6 carbon atoms including, but not limited to:

    
    
        a. alkyl having from 1 to 6 carbon atoms, including, but not limited to:
        
            linear alkyl, e.g. methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, etc.,
            branched alkyl, e.g. iso-propyl, t-butyl and other branched butyl isomers, branched pentyl isomers, etc.,
            cycloalkyl, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.,
            combinations of linear, branched, and/or cycloalkyl;
        
        
        b. alkenyl having from 1 to 6 carbon atoms, e.g. hydrocarbyl having 1 or more double bonds, including linear, branched, or cycloalkenyl
        c. alkynyl having from 1 to 6 carbon atoms, e.g. hydrocarbyl having 1 or more triple bonds, including linear, branched, or cycloalkenyl;
        d. combinations of alkyl, alkenyl, and/or akynyl
    
    


alkyl-CN having from 1 to 6 carbon atoms; hydroxyalkyl, i.e. alkyl-OH, such as hydroxymethyl, hydroxyethyl, and the like;
ether substituents, including O-alkyl, alkyl-O-alkyl, and the like, having from 1 to 6 carbon atoms;
thioether substituents, including S-alkyl, alkyl-5-alkyl, and the like, having from 1 to 6 carbon atoms;
amine substituents, including NH2, NH-alkyl, N-alkyl1alkyl2 (i.e., alkyl1 and alkyl2 are the same or different, both attached to N), alkyl-NH2, alkyl-NH-alkyl, alkyl-N-alkyl1alkyl2, and the like;
ester substituents, including CO2-alkyl, CO2-phenyl, etc., having from 1 to 6 carbon atoms;
other carbonyl substituents, including aldehydes; ketones, such as acyl (i.e.




), and the like;

phenyl, provided that the ring and any substituents remain with the constraints defined herein;
fluorocarbons or hydrofluorocarbons such as CF3, CH2CF3, etc.; and
CN;
combinations of the above are also possible, subject to the constraints defined;
Alternatively, a substituent may be F, Cl, Br, or I.
Substituents must be sufficiently stable to be stored in a bottle at room temperature under a normal atmosphere for at least 12 hours, or stable enough to be useful for any purpose disclosed herein.
If a substituent is a salt, for example of a carboxylic acid or an amine, the counter-ion of said salt, i.e. the ion that is not covalently bonded to the remainder of the molecule is not counted for the purposes of the number of heavy atoms in a substituent. Thus, for example, the salt —CO2−Na+ is a stable substituent consisting of 3 heavy atoms, i.e. sodium is not counted. In another example, the salt —NH(Me)2+Cl− is a stable substituent consisting of 3 heavy atoms, i.e. chlorine is not counted.
B is alkyl having 1, 2, 3, or 4 carbon atoms; or B is H or substituted or unsubstituted phenyl, wherein the dashed line is not a covalent bond. In other words B can be:
C1-4 alkyl, e.g. methyl, ethyl, propyl isomers, butyl isomers, etc., including linear, branched, and cyclic alkyl (e.g. cyclopropyl, cyclobutyl) or a combination of linear, branched, and/or cyclic alkyl; or
B can be H, so that a compound has the formula below.




Or B can be substituted or unsubstituted phenyl and the dashed line is not a covalent bond. For example, compounds according the structure below are possible, wherein Ra and Rb are independently H, or are substituents as defined herein.




In one embodiment, A is phenyl substituted with 0, 1, 2, 3, or 4 substituents, wherein the substituents are independently alkyl having from 1 to 4 carbon atoms or a halogen.
In another embodiment, the substituents of A are independently methyl, ethyl, F, Cl, or Br.
In another embodiment, A is unsubstituted phenyl.
Another embodiment is a compound having a formula




wherein m is 0 or 1; and
Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.
Another embodiment is a compound having a formula




wherein Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.
Another embodiment is a compound having a formula




wherein m is 0 or 1; and
Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.
Another embodiment is a compound having a formula




wherein Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.
Another embodiment is a compound having a formula




wherein Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.
Another embodiment is a compound having a formula




wherein Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.
Another embodiment is a compound having a formula




wherein Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.
Another embodiment is a compound having a formula




wherein A is substituted or unsubstituted phenyl; and
B is substituted or unsubstituted phenyl.
Hypothetical examples of useful embodiments are depicted below.










For the purposes of this disclosure, “treat,” “treating,” or “treatment” refer to the use of a compound, composition, therapeutically active agent, or drug in the diagnosis, cure, mitigation, treatment, prevention of disease or other undesirable condition.
These compounds may be formulated into solid, liquid, or other types of dosage forms using methods known in the art. Both formulation of dosage forms and determination of a therapeutically effective dose can be readily made by a person of ordinary skill using routine methods.


BIOLOGICAL DATA
Receptor Selection and Amplification Technology (RSAT) Assay
The RSAT assay measures a receptor-mediated loss of contact inhibition that results in selective proliferation of receptor-containing cells in a mixed population of confluent cells. The increase in cell number is assessed with an appropriate transfected marker gene such as □-galactosidase, the activity of which can be easily measured in a 96-well format. Receptors that activate the G protein, Gq, elicit this response. Alpha2 receptors, which normally couple to Gi, activate the RSAT response when coexpressed with a hybrid Gq protein that has a Gi receptor recognition domain, called Gq/i5.
NIH-3T3 cells are plated at a density of 2×106 cells in 15 cm dishes and maintained in Dulbecco's modified Eagle's medium supplemented with 10% calf serum. One day later, cells are cotransfected by calcium phosphate precipitation with mammalian expression plasmids encoding p-SV-□-galactosidase (5-10 μg), receptor (1-2 μg) and G protein (1-2 μg). 40 μg salmon sperm DNA may also be included in the transfection mixture. Fresh media is added on the following day and 1-2 days later, cells are harvested and frozen in 50 assay aliquots. Cells are thawed and 100 μl added to 100 μl aliquots of various concentrations of drugs in triplicate in 96-well dishes. Incubations continue 72-96 hr at 37° C. After washing with phosphate-buffered saline, □-galactosidase enzyme activity is determined by adding 200 μl of the chromogenic substrate (consisting of 3.5 mM o-nitrophenyl-□-D-galactopyranoside and 0.5% nonidet P-40 in phosphate buffered saline), incubating overnight at 30° C. and measuring optical density at 420 nm. The absorbance is a measure of enzyme activity, which depends on cell number and reflects a receptor-mediated cell proliferation. The efficacy or intrinsic activity is calculated as a ratio of the maximal effect of the drug to the maximal effect of a standard full agonist for each receptor subtype. Brimonidine, also called UK14304, the chemical structure of which is shown below, is used as the standard agonist for the alpha2A, alpha2B and alpha2C receptors. The EC50 is the concentration at which the drug effect is half of its maximal effect.




The results of the RSAT assay with several exemplary compounds of the invention are disclosed in Table 1 above together with the chemical formulas of these exemplary compounds. EC50 values are nanomolar. NA stands for “not active” at concentrations less than 10 micromolar. IA stands for “intrinsic activity.”











TABLE 1









Alpha 2A
Alpha 2B
Alpha 2C














EC50
IA
EC50
IA
EC50
IA





















not active

1450
0.82
2640 
0.32


 






not active

783
0.35
not active


 






not active

341
0.87
358
0.58


 






not active

73.9
0.95
914
0.51


 






not active

417
0.47
1780
0.33


 






not active

2570
0.74
not active


 






not active

176
0.92
not active


 






not active

988
0.3
not active


 






not active

282
0.36
not active


 






not active

78.9
0.93
472
0.84


 






not active

167
0.42
376
0.4


 






not active

232
0.31
946
0.36


 






not active

518
0.34
not active


 






not active

94.3
1.06
1480 
0.41


 






not active

296
0.37
not active


 






not active

high
0.35
not active


 






not active

231
0.69
1970 
0.42


 






not active

1040
0.59
not active


 






not active

941
0.85
not active


 






not active

475
0.65
not active


 






not active

642
0.7
not active


 






759
0.35
60.1
1.09
1530 
0.46


 






not active

560
0.5
not active


 






not active

98.6
0.73
not active









Synthetic Methods
General Procedure A for the Synthesis of 1-(2-Fluoroethyl)-3-Aryl Cyanoguanidines




Fluoroethyl amine hydrochloride (5.50 g, 90% purity, 49.75 mmol) was added to a solution of diphenyl cyanocarbonimidate (11.84 g, 49.70 mmol) in CH3CN, followed by addition of diisopropylethyl amine (17.30 mL, 99.32 mmol). After stirring for 14 hours, the reaction mixture was concentrated and the residue was taken up in EtOAc. The organic layer was washed sequentially with H2O (3×75 mL) and aq 2N KOH (3×100 mL), then concentrated to give a viscous oil, which was solidified upon standing at room temperature. Recrystallization from ether gave the desired 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea intermediate. A portion of this intermediate was mixed with an appropriate amine in CH3CN. The resulting reaction mixture was refluxed for 14 hours. After cooling to room temperature, the mixture was diluted with EtOAc and the resulting organic phase was washed with H2O (3×75 mL) and then concentrated. The residue was purified by column chromatography using hex:EtOAc (2:3) as eluant to give a semi-pure product. Recrystallization from EtOAc afforded the final pure cyanoguanidine.




Synthesis of 1-(3-Bromo-benzyl)-3-(2-fluoro-ethyl)-cyanoguanidine
The title compound was generated from the commercially available 3-bromobenzylamine according to the general procedure A described above.
1-(3-Bromo-benzyl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 3-bromo-benzylamine (1.70 g, 9.00 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) in CH3CN according to general procedure A described above. Spectroscopic data: 1H NMR (300 MHz, DMSO-) □ 3.4 (q, J=5.3 Hz, 1H), 3.5 (q, J=5.3 Hz, 1H), 4.30-4.41 (m, 3H), 4.5 (t, J=5.0 Hz, 1H), 7.24-7.34 (m, 3H), 7.41-7.49 (m, 2H), 7.7 (t, J=6.2 Hz, 1H).




Synthesis of 1-(2,3-dihydro-benzofuran-7-ylmethyl)-3-(2-fluoro-ethyl)-cyanoguanidine
The desired starting amine was obtained from the commercially available 2,3-dihydrobenzofuran according to the protocol described in the scheme below. The title compound was thus obtained from this amine according to general procedure A described above.




2,3-Dihydro-benzofuran-7-carbaldehyde: sec-BuLi (20.00 ml, 1.4 M in cyclohexane, 28.00 mmol) was added to a solution of 2,3-dihydro-benzofuran (2.40 mL, 21.30 mmol) and TMEDA (10.00 mL) in THF at −20° C. The resulting mixture was stirred for 1 hour, then DMF (3.00 mL, 38.75 mmol) was added and stirring was continued for another 30 minutes. The reaction mixture was quenched with water and diluted with ether. The resulting solution was washed with brine, dried over MgSO4 and concentrated to afford the desired title aldehydei. i Tasker, Andrew S.; Sorensen, Bryan K.; Jae, Hwan-Soo; Winn, Martin; Geldern, Thomas W. von; et al. J. Med. Chem. 1997, 40, 322-330.
(2,3-Dihydro-benzofuran-7-yl)-methanol: 2,3-Dihydro-benzofuran-7-carbaldehyde (1.50 g, 10.20 mmol) was dissolved in ether, then cooled to 0° C., NaBH4 (400 mg, 10.57 mmol) in MeOH (5.00 mL) was added. The resulting reaction mixture was stirred for 30 min, then saturated ammonium chloride was added. The mixture was extracted with ether, and the combined organic phases were washed with brine, then dried over magnesium sulfate and concentrated to afford the desired alcohol.
C-(2,3-Dihydro-benzofuran-7-yl)-methylamine: (2,3-dihydro-benzofuran-7-yl)-methanol (1.50 g, 10.00 mmol) was dissolved in dichloromethane and cooled to −55° C., then MsCl (1.30 mL, 16.80 mmol) was added, followed by addition of Et3N (3.0 mL, 21.52 mmol). The resulting reaction mixture was stirred at this temperature for 2 hours, then saturated aq ammonium chloride was added. The reaction mixture was extracted with ether. The combined organic phases were washed with brine, then dried over magnesium sulfate and concentrated to give the crude mesylate. The mesylate was then dissolved in DMSO, and treated with NaN3 (1.30 g, 20.00 mmol) at room temperature for 14 hours. The reaction mixture was diluted with water, and extracted with ether. The combined organic phases were washed with water, brine, and then dried over magnesium sulfate and concentrated to afford the desired azide. This azido compound was then dissolved in THF:H2O (3:1), Ph3P (2.70 g, 10.29 mmol) was added, followed by KOH (600 mg, 10.69 mmol). The resulting mixture was stirred for 14 hours. The reaction mixture was then diluted with H2O and slowly acidified with HCl and the aqueous layer was washed with Et2O (3×50 mL). The aqueous layer was then basified with NaOH (pH 14) and extracted with Et2O (3×50 mL). The combined organic extracts were washed with H2O (1×25 mL), brine (1×25 mL), dried over K2CO3 and concentrated to give the desired title amine.
1-(2,3-Dihydro-benzofuran-7-ylmethyl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from (2,3-dihydro-benzofuran-7-yl)-methylamine (1.40 g, 9.40 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-) □ 3.2 (t, J=8.8 Hz, 2H), 3.39-3.54 (m, 2H), 4.3 (d, J=6.7 Hz, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.47-4.60 (m, 3H), 6.8 (t, J=7.6, 7.0 Hz, 1H), 7.0 (d, J=7.6 Hz, 1H), 7.10-7.22 (m, 2H), 7.4 (t, J=5.9, 5.3 Hz, 1H).




Synthesis of 1-(2-chloro-3-methyl-benzyl)-3-(2-fluoro-ethyl)-cyanoguanidine
The desired starting amine was prepared from 2-chloro-m-xylene according to the procedures shown in the scheme below. The title compound was thus obtained from this amine according to general procedure A described above.




1-Bromomethyl-2-chloro-3-methyl-benzeneii: A solution of 2-chloro-m-xylene (5.00 g, 35.60 mmol), NBS (5.70 g, 32.03 mmol), and a catalytic amount of benzoyl peroxide (100 mg) in CCl4 was refluxed for 1 hour. After cooling to room temperature the resulting mixture was filtered and the filtrate was distilled off. Purification by column chromatography using pentane as eluant followed by distillation afforded the title compound. Spectroscopic data: 1H NMR (300 MHz, CD) □ 2.39 (s, 3H), 4.61 (s, 2H), 7.08-7.23 (m, 2H), 7.25-7.30 (m, 1H). ii Zhang, Jin-Tao; Dai, Wei; Harvey, Ronald G. J. Org. Chem. 1998, 63, 8125-8132.
1-Azidomethyl-2-chloro-3-methyl-benzene: A solution of 1-bromomethyl-2-chloro-3-methyl-benzene (3.68 g, 16.80 mmol) and NaN3 (2.70 g, 41.53 mmol) in DMSO was stirred at 55° C. for 14 hours. The reaction mixture was then cooled to room temperature, water was added and the resulting mixture was extracted with Et2O (3×100 mL). The combined organic phases were washed with H2O (2×100 mL) and brine (1×100 mL), then dried over MgSO4 and concentrated to afford the title azido compound. Spectroscopic data: 1H NMR (300 MHz, CDCl)  2.37-2.45 (s, 3H), 4.49 (s, 2H), 7.15-7.27 (m, 3H).
2-Chloro-3-methyl-benzylamine: 1-Azidomethyl-2-chloro-3-methyl-benzene (2.99 g, 16.50 mmol) was dissolved in THF:H2O (3:1), triphenyl phosphine (4.40 g, 16.78 mmol) was added, followed by KOH (923 mg, 16.45 mmol) and the resulting mixture was stirred for 14 hours. The reaction mixture was then diluted with H2O, slowly acidified with HCl and the resulting aqueous layer was washed with Et2O (3×50 mL). The aqueous layer was then basified with NaOH (pH 14), extracted with Et2O (3×100 mL). The combined organic phases were washed with H2O (1×50 mL) and brine (1×50 mL), then dried over K2CO3 and concentrated to give the title amine.
1-(2-Chloro-3-methyl-benzyl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 2-chloro-3-methyl-benzylamine (2.80 g, 18.00 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (2.00 g, 9.65 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 2.4 (s, 3H), 3.38-3.48 (m, 1H), 3.48-3.59 (m, 1H), 4.35-4.47 (m, 3H), 4.6 (t, J=5.0 Hz, 1H), 7.03-7.13 (m, 1H), 7.21-7.35 (m, 3H), 7.6 (t, J=5.9, 5.3 Hz, 1H). 13C NMR (75 MHz, DMSO-d6)  20.5, 42.3 (d, J=21.8 Hz), 43.5, 82.7 (d, J=166.4 Hz), 118.3, 125.8, 127.2 (2C), 130.3, 132.6, 136.6, 160.3.




Synthesis of 1-(2-fluoro-ethyl)-3-indan-2-yl-cyanoguanidine
The title compound was generated from the commercially available indan-2-ylamine according to the general procedure A described above.
1-(2-Fluoro-ethyl)-3-indan-2-yl-cyanoguanidine: The title compound was obtained from indan-2-ylamine (1.20 g, 9.01 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 2.85-2.98 (m, 2H), 3.14-3.27 (m, 2H), 3.40-3.55 (m, 2H), 4.0 (q, J=7.0 Hz, 1H), 4.37-4.50 (m, 1H), 4.6 (t, J=5.0 Hz, 1H), 7.11-7.25 (m, 6H).
General Procedure B for the Synthesis of fluoroethyl Substituted Indan Cyanoguanidines




NaBH3CN (7.0 eq) was added to a solution of an indanone in isopropanol. NH4OAc (30 eq) was then added and the resulting mixture was stirred at room temperature for 4 hours, then refluxed for 22 hours. After cooling to room temperature, the reaction mixture was quenched with 200 mL of 2.5 N aq. NaOH. The layers were then separated and the aqueous layer was extracted with CH2Cl2. The combined organic extracts were washed with H2O (75 mL), dried over K2CO3 and concentrated to give the desired indan amine. The final fluoroethyl cyanoguanidines were thus obtained according to the protocol described in General Procedure A.




Synthesis of 1-(2-fluoro-ethyl)-3-(4-methyl-indan-1-yl)-cyanoguanidine
The title compound was generated from the commercially available 4-methylindanone according to general procedure B described above. The intermediate 4-methylindan-1-ylamine was isolated and characterized.
4-Methyl-indan-1-ylamine: The title amine was generated from 4-methyl-indan-1-one (5.00 g, 34.20 mmol), NaBH3CN (15.00 g, 0.24 mol) and NH4OAc (79.00 g, 1.02 mol) according to the protocols as outlined in general procedure B described above.
1-(2-Fluoro-ethyl)-3-(4-methyl-indan-1-yl)-cyanoguanidine: The title compound was obtained from 4-methyl-indan-1-ylamine (5.00 g, 33.96 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (3.80 g, 18.34 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 11.83-1.96 (m, 1H), 2.2 (s, 3H), 2.38-2.51 (m, 1H), 2.61-2.74 (m, 1H), 2.83-2.95 (m, 1H), 3.40-3.48 (m, 1H), 3.52-3.56 (m, 1H), 4.4 (t, J=5.0 Hz, 1H), 4.6 (t, J=5.0 Hz, 1H), 5.3 (q, J=7.9 Hz, 1H), 7.02-7.15 (m, 3H), 7.19-7.28 (m, 2H). 13C NMR (75 MHz, DMSO-d)  19.1, 28.8, 33.0, 42.2 (d, J=21.8 Hz), 57.4, 82.8 (d, J=166.4 Hz), 118.4, 121.9, 127.3, 128.9, 134.2, 142.4, 143.5, 159.9.




Synthesis of 1-(2-fluoro-ethyl)-3-(6-methyl-indan-1-yl)-cyanoguanidine
The title compound was generated from the commercially available 6-methylindanone according to general procedure B described above. The intermediate 6-methylindan-1-ylamine was isolated and characterized.
6-Methyl-indan-1-ylamine: The title amine was obtained from 6-methyl-indan-1-one (5.00 g, 34.20 mmol), NaBH3CN (15.00 g, 0.24 mol) and NH4OAc (79.00 g, 1.02 mol) according to the protocols as outlined in general procedure B described above.
1-(2-Fluoro-ethyl)-3-(6-methyl-indan-1-yl)-cyanoguanidine: The title compound was obtained 6-methyl-indan-1-ylamine (1.30 g, 8.80 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.82-1.95 (m, 1H), 2.3 (s, 3H), 2.34-2.48 (m, 1H), 2.65-2.78 (m, 1H), 2.81-2.93 (m, 1H), 3.43-3.58 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.6 (t, J=5.0 Hz, 1H), 5.2 (q, J=7.9 Hz, 1H), 6.99-7.07 (m, 2H), 7.09-7.16 (m, 1H), 7.21-7.30 (m, 2H).




Synthesis of 1-(2-fluoro-ethyl)-3-(indan-1-yl)-cyanoguanidine
The title compound was generated from the commercially available indan-1-ylamine according to general procedure A described above.
1-(2-Fluoro-ethyl)-3-indan-1-yl-cyanoguanidine: The title compound was obtained from indan-1-ylamine (1.20 g, 9.01 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.84-1.99 (m, 1H), 2.37-2.51 (m, 1H), 2.71-2.84 (m, 1H), 2.88-2.99 (m, 1H), 3.43-3.59 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.6 (t, J=5.0 Hz, 1H), 5.3 (q, J=8.2, 7.6 Hz, 1H), 7.19-7.32 (m, 6H). 13C NMR (75 MHz, DMSO-d) □ 30.3, 33.6, 42.3 (d, J=20.7 Hz), 57.1, 82.8 (d, J=165.2 Hz), 118.4, 124.5, 125.2, 127.1, 128.3, 143.5, 143.9, 160.0.




Synthesis of (S)-(+)-1-(2-fluoro-ethyl)-3-(indan-1-yl)-cyanoguanidine
The title compound was generated from the commercially available (S)-(+)-indan-1-ylamine according to general procedure A described above.
(S)-(+)-1-(2-Fluoro-ethyl)-3-(indan-1-yl)-cyanoguanidine: The title compound was obtained from (S)-(+)-indan-1-ylamine (1.20 g, 9.01 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.84-1.99 (m, 1H), 2.37-2.52 (m, 1H), 2.71-2.84 (m, 1H), 2.88-2.99 (m, 1H), 3.42-3.58 (m, 2H), 4.4 (t, J=5.3, 4.7 Hz, 1H), 4.6 (t, J=5.0 Hz, 1H), 5.3 (q, J=8.2, 7.6 Hz, 1H), 7.18-7.32 (m, 6H). 13C NMR (75 MHz, DMSO-d6)  30.3, 33.6, 42.3 (d, J=20.7 Hz), 57.2, 82.8 (d, J=166.4 Hz), 118.5, 124.5, 125.2, 127.1, 128.3, 143.5, 143.9, 160.0.
General Procedure C for the Synthesis of Fluoroethyl Substituted Indan Cyanoguanidines




To a solution of 3-(substituted-phenyl)-propionic acid in CH2Cl2 at 0° C. was added oxalyl chloride (1.5 eq) followed by 2-3 drops of DMF (in case of SOCl2, benzene would be used as solvent, and the reaction mixture would be refluxed for 3 hours). The resulting mixture was stirred until no more gas evolution was observed. After concentration of the reaction mixture, the residue was dissolved in CH2Cl2, cooled to 0° C., and AlCl3 (1.0 eq) was added in 3 batches at 3-minute interval. After stirring for 1 hour, the reaction mixture was quenched in ice-water and the layers were separated. The aqueous layer was extracted with Et2O (3×150 mL) and the combined organic extracts were washed with H2O (3×100 mL), saturated NaHCO3 (3×100 mL), brine (1×100 mL), dried over MgSO4 and concentrated. Purification by column chromatography using hexane:EtOAc (4.5:0.5) as eluant gave the desired substituted indanone. The indanone was thus converted to the desired fluoroethyl cyanoguanidines via the protocols described in general procedure B.




Synthesis of 1-(4-bromo-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine
The title compound was generated from the commercially available 3-(2-bromophenyl)propionic acid according to general procedure C described above. The intermediates 4-bromoindan-1-one and 4-bromoindan-1-ylamine were separated and characterized.
4-Bromo-indan-1-oneiii: The title compound was obtained from 3-(2-bromo-phenyl)-propionic acid (10.00 g, 43.70 mmol), SOCl2 (5.00 mL, 68.55 mmol) and AlCl3 (6.40 g, 48.00 mmol) according to the protocols as outlined in general procedure C. iii Faller, P. Bull. Soc. Chim. Fr. 1966, 3618-3625.
4-Bromo-indan-1-ylamine: The title amine was generated from 4-bromo-indan-1-one (5.00 g, 23.70 mmol), NaBH3CN (10.40 g, 165.50 mmol) and NH4OAc (54.80 g, 710.95 mmol) according to the protocols as outlined in general procedure B described above.
1-(4-Bromo-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 4-bromo-indan-1-ylamine (1.90 g, 8.96 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.88-2.01 (m, 1H), 2.40-2.53 (m, 1H), 2.70-2.84 (m, 1H), 2.89-2.99 (m, 1H), 3.41-3.57 (m, 2H), 4.4 (t, J=5.3 Hz, 1H), 4.6 (t, J=5.0 Hz, 1H), 5.4 (q, J=7.6 Hz, 1H), 7.16-7.26 (m, 2H), 7.3 (t, J=5.9, 5.3 Hz, 1H), 7.4 (d, J=8.5 Hz, 1H), 7.5 (d, J=7.6 Hz, 1H). 13C NMR (75 MHz, DMSO-d6)  31.8, 32.4, 42.3 (d, J=20.7 Hz), 57.9, 82.7 (d, J=166.4 Hz), 118.3, 120.0, 124.0, 129.5, 131.1, 143.7, 146.3, 159.8.




Synthesis of 1-(4-chloro-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine
The desired 3-(2-chlorophenyl)propionic acid was obtained from hydrogenation of the commercially available 3-(2-chlorophenyl)acrylic acid. The title compound was thus generated from the 3-(2-chlorophenyl)propionic acid according to general procedure C described above. The intermediates 4-chloroindan-1-one and 4-chloroindan-1-ylamine were separated and characterized.
4-Chloro-indan-1-oneiv: 3-(2-chloro-phenyl)-acrylic acid (10.00 g, 55.00 mmol) in THF was mixed with Rh/Al2O3 (500 mg) and hydrogenated for 14 hours. The reaction mixture was filtered through celite and the filtrate was concentrated to give 3-(2-chloro-phenyl)-propionic acid. 3-(2-chloro-phenyl)-propionic acid (10.0 g, 43.70 mmol) was then reacted with SOCl2 (6.00 mL, 82.26 mmol) and AlCl3 (8.00 g, 60.00 mmol) according to the protocols as outlined in general procedure C to afford the title chloroindanone. iv Berrier, C.; Gesson, J. P.; Jacquesy, J. C.; Renoux, A. Tetrahedron 1984, 40, 4973-4980.
4-Chloro-indan-1-ylaminev: 4-Chloro-indan-1-one (5.00 g, 30.10 mmole), NaBH3CN (13.20 g, 0.21 mol) and NH4OAc (70.00 g, 0.91 mol) in isopropanol were reacted according to the protocols as outlined in general procedure B to give the desired title amine. v Eli Lilly and Co. Indianapolis, Ind. (V.St.A), DE 2812578, 1978, Chem. Abstr. 90, 54730.
1-(4-Chloro-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 4-chloro-indan-1-ylamine (1.50 g, 9.00 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.88-2.02 (m, 1H), 2.40-2.53 (m, 1H), 2.73-2.86 (m, 1H), 2.90-3.04 (m, 1H), 3.41-3.57 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.6 (t, J=5.3 Hz, 1H), 5.4 (q, J=8.2, 7.6 Hz, 1H), 7.2 (t, J=8.2, 7.0 Hz, 1H), 7.25-7.35 (m, 3H), 7.4 (d, J=8.5 Hz, 1H). 13C NMR (75 MHz, DMSO-d6)  29.6, 32.6, 42.3 (d, J=20.7 Hz), 57.6, 82.7 (d, J=166.4 Hz), 118.3, 123.4, 128.1, 129.3, 130.4, 141.6, 146.5, 159.8.




Synthesis of 1-(2-fluoro-ethyl)-3-(4-fluoro-indan-1-yl)-cyanoguanidine
The desired 3-(2-fluorophenyl)propionic acid was obtained from hydrogenation of the commercially available 3-(2-fluorophenyl)acrylic acid. The title compound was thus generated from this acid according to general procedure C described above. The intermediates 4-fluoroindan-1-one and 4-fluoroindan-1-ylamine were separated and characterized.
4-Fluoro-indan-1-onevi: 3-(2-fluoro-phenyl)-acrylic acid (10.00 g, 60.30 mmol) in THF was mixed with Rh/Al2O3 (500 mg) and hydrogenated for 14 hours. The reaction mixture was filtered through celite and the filtrate was concentrated to give 3-(2-fluoro-phenyl)-propionic acid. 3-(2-chloro-phenyl)-propionic acid (10.0 g, 43.70 mmol) was then reacted with SOCl2 (6.60 mL, 90.48 mmol) and AlCl3 (9.00 g, 67.50 mmol) according to the protocols as outlined in general procedure C to afford the title compound. vi Musso, David L.; Cochran, Felicia R.; Kelley, James L.; McLean, Ed W.; Selph, Jeffrey L.; Rigdon, Greg C.; Orr, G. Faye; Davis, Ronda G.; Cooper, Barrett R.; Styles, Virgil L.; Thompson, James B.; Hall, William R. J. Med. Chem. 2003, 46, 399-408.
4-Fluoro-indan-1-ylamine: The title compound was obtained from 4-fluoro-indan-1-one (5.00 g, 33.30 mmol), NaBH3CN (14.70 g, 0.23 mol) and NH4OAc (77.00 g, 1.00 mol) according to the protocols as outlined in general procedure B described above.
1-(2-Fluoro-ethyl)-3-(4-fluoro-indan-1-yl)-cyanoguanidine: The title compound was obtained from 4-fluoro-indan-1-ylamine (1.40 g, 9.30 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.90-2.04 (m, 1H), 2.42-2.55 (m, 1H), 2.71-2.85 (m, 1H), 2.93-3.06 (m, 1H), 3.44-3.59 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.6 (t, J=4.7 Hz, 1H), 5.4 (q, J=8.2 Hz, 1H), 7.03-7.13 (m, 2H), 7.19-7.48 (m, 3H). 13C NMR (75 MHz, DMSO-d6)  26.1, 33.3, 42.3 (d, J=20.7 Hz), 57.2 (d, J=2.3 Hz), 82.7 (d, J=166.4 Hz), 114.7 (d, J=20.7 Hz), 118.3, 120.7 (d, J=2.3 Hz), 129.3 (d, J=6.9 Hz), 129.5 (d, J=5.7 Hz), 147.9 (d, J=5.7 Hz), 159.3 (d, J=244.4 Hz), 159.9.




Synthesis of 1-(2-fluoro-ethyl)-3-(6-fluoro-indan-1-yl)-cyanoguanidine
The desired 3-(4-fluorophenyl)propionic acid was obtained from hydrogenation of the commercially available 3-(4-fluorophenyl)acrylic acid. The title compound was thus generated from this acid according to general procedure C described above. The intermediates 6-fluoroindan-1-one and 6-fluoroindan-1-ylamine were separated and characterized.
6-Fluoro-indan-1-one6: 3-(4-Fluoro-phenyl)-acrylic acid (25.00 g, 151.00 mmol) in THF was mixed with Rh/Al2O3 (1.00 g) and hydrogenated for 14 hours. The reaction mixture was filtered through celite and the filtrate was concentrated to give 3-(4-fluoro-phenyl)-propionic acid. 3-(4-fluoro-phenyl)-propionic acid was then reacted with SOCl2 (16.50 mL, 0.23 mol) and AlCl3 (22.00 g, 0.16 mol) according to the protocols as outlined in general procedure C to afford the title compound.
6-Fluoro-indan-1-ylamine: The title amine was obtained from 6-fluoro-indan-1-one (5.00 g, 33.30 mmol), NaBH3CN (14.70 g, 0.23 mol) and NH4OAc (77.00 g, 1.00 mol) according to the protocols as outlined in general procedure B described above.
1-(2-Fluoro-ethyl)-3-(6-fluoro-indan-1-yl)-cyanoguanidine: The title compound was obtained from 6-fluoro-indan-1-ylamine (1.40 g, 9.30 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.87-2.02 (m, 1H), 2.39-2.54 (m, 1H), 2.68-2.81 (m, 1H), 2.85-2.96 (m, 1H), 3.43-3.58 (m, 2H), 4.4 (t, J=5.3, 4.7 Hz, 1H), 4.6 (t, J=5.0 Hz, 1H), 5.3 (q, J=8.2, 7.3 Hz, 1H), 6.96-7.10 (m, 2H), 7.24-7.39 (m, 3H). 13C NMR (75 MHz, DMSO-d6) □ 29.5, 34.1, 42.3 (d, J=20.7 Hz), 57.1, 82.8 (d, J=166.4 Hz), 111.3 (d, J=21.8 Hz), 115.1 (d, J=21.8 Hz), 118.4, 126.5 (d, J=8.0 Hz), 139.3 (d, J=2.3 Hz), 146.3 (d, J=6.9 Hz), 160.0, 162.1 (d, J=242.1 Hz).




Synthesis of 1-(6-chloro-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine
The desired 3-(4-chlorophenyl)propionic acid was obtained from hydrogenation of the commercially available 3-(4-chlorophenyl)acrylic acid. The title compound was thus generated from this acid according to general procedure C described above. The intermediates 6-chloroindan-1-one and 6-chloroindan-1-ylamine were separated and characterized.
6-Chloro-indan-1-one6: 3-(4-Chloro-phenyl)-acrylic acid (25.00 g, 0.14 mol) in THF was mixed with Rh/Al2O3 (1.00 g) and hydrogenated for 14 hours. The reaction mixture was filtered through celite and the filtrate was concentrated to give 3-(4-chloro-phenyl)-propionic acid. 3-(4-chloro-phenyl)-propionic acid was then reacted with SOCl2 (15.00 mL, 0.21 mol) and AlCl3 (20.20 g, 0.15 mol) according to the protocols as outlined in general procedure C to afford the title compound.
6-Chloro-indan-1-ylamine: The title compound was obtained from 6-Chloro-indan-1-one (5.00 g, 30.00 mmol), NaBH3CN (13.30 g, 0.21 mol) and NH4OAc (70.00 g, 0.91 mol) according to the protocols as outlined in general procedure B.
1-(6-Chloro-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 6-chloro-indan-1-ylamine (1.50 g, 9.01 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.87-2.00 (m, 1H), 2.39-2.52 (m, 1H), 2.69-2.82 (m, 1H), 2.85-2.97 (m, 1H), 3.43-3.59 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.6 (t, J=5.3, 4.7 Hz, 1H), 5.3 (q, J=8.2 Hz, 1H), 7.2 (br s, 1H), 7.25-7.33 (m, 3H), 7.4 (d, J=8.2 Hz, 1H). 13C NMR (75 MHz, DMSO-d6)  29.8, 33.8, 42.3 (d, J=20.7 Hz), 57.0, 82.8 (d, J=166.4 Hz), 118.3, 124.5, 126.9, 128.1, 131.6, 142.5, 146.4, 160.0.




Synthesis of 1-(4-ethyl-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine




The title compound was generated from commercially available 1-bromo2-ethylbenzene according to the scheme above. The intermediates 2-ethylbenzaldehyde, 3-(2-ethyl-phenyl)-acrylic acid, 4-ethyl-1-indanone and 4-ethylindan-1-ylamine were isolated and characterized.
2-Ethyl-benzaldehydevii: A solution of 1-bromo-2-ethyl-benzene (5.00 g, 27.02 mmol), Mg (4.00 g, 0.16 mol) and a catalytic amount of 12 in THF was refluxed for 2 hours. After cooling the reaction mixture to 0° C., DMF (10.00 mL) was added and the mixture was stirred for 30 minutes. It was then quenched with 10% HCl and the resulting solution was extracted with Et2O (3×200 mL). The combined organic extracts were washed with H2O (2×200 mL), brine (1×200 mL), dried over MgSO4 and concentrated to give the title compound. vii Nakamura, Y.; O-kawa, K.; Minami, S.; Ogawa, T.; Tobita, S.; Nishimura, J. J. Org. Chem. 2002, 67, 1247-1252.
3-(2-Ethyl-phenyl)-acrylic acidviii: To a solution of 2-ethyl-benzaldehyde (18.40 g, 0.14 mol) and malonic acid (28.00 g, 0.27 mol) in pyridine was added 10.00 mL of piperidine and the resulting mixture was slowly refluxed for 3 hours. After cooling to room temperature, the reaction mixture was diluted with ice water, acidified to pH<1. The resulting solid was filtered, washed with water and dried under vacuum to give the title compound. viii Cope, A. C.; Liss, T. A.; Smith, D. S. J. Am. Chem. Soc. 1957, 79, 240-243.
4-Ethyl-indan-1-one: 3-(2-Ethyl-phenyl)-acrylic acid (17.00 g, 96.48 mmol) in THF was mixed with Pd/C (1.50 g) and hydrogenated at 50 psi for 6 hours. The resulting mixture was filtered through a pad of celite and the filtrate was concentrated to give 3-(2-ethyl-phenyl)-propionic acid. The acid was reacted with SOCl2 (5.00 mL, 68.55 mmol) and AlCl3 (6.70 g, 50.25 mmol) according to the protocols as outlined in general procedure C to give the title compound.
4-Ethyl-indan-1-ylamine: 4-Ethyl-indan-1-one (5.00 g, 31.21 mmol), NaBH3CN (13.70 g, 0.22 mol) and NH4OAc (72.00 g, 0.93 mol) in isopropanol were reacted according to the protocols as outlined in general procedure B to give the desired amine.
1-(4-Ethyl-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 4-ethyl-indan-1-ylamine (1.50 g, 9.30 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.1 (t, J=7.6 Hz, 3H), 1.82-1.97 (m, 1H), 2.41-2.46 (m, 1H), 2.6 (q, J=7.6 Hz, 2H), 2.65-2.77 (m, 1H), 2.88-2.99 (m, 1H), 3.41-3.57 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.6 (t, J=5.0 Hz, 1H), 5.3 (q, J=8.5, 7.9 Hz, 1H), 7.1 (t, J=7.3 Hz, 2H), 7.2 (t, J=7.6 Hz, 1H), 7.24-7.33 (m, 2H). 13C NMR (75 MHz, DMSO-d6) □ 15.1, 26.2, 28.4, 33.1, 42.2 (d, J=20.7 Hz), 57.3, 82.8 (d, J=166.4 Hz), 118.5, 122.0, 127.3, 127.5, 140.3, 141.6, 143.7, 159.9.




Synthesis of (S)-(+)-1-(2-fluoro-ethyl)-3-(4-methyl-indan-1-yl)-cyanoguanidine




The desired chiral starting amine was generated from the commercially available 4-methylindan-1-one according to the chemistry described in the scheme above. The title compound was thus obtained from this amine according to general procedure A. The intermediates (R)-4-methyl-indan-1-ol and (S)-4-methyl-indan-1-ylamine were separated and characterized.
(R)-4-Methyl-indan-1-ol: To a solution of 4-methyl-indan-1-one (5.00 g, 34.20 mmole) and (S)-2-methyl-CBS-oxazaborolidine (5.00 mL, 1.0 M in THF, 5.00 mmol) in THF at −20° C. was added borane-methylsulfide (12.00 mL, 1.0 M in THF, 12.00 mmol) over 20 minutes. The resulting mixture was then stirred for 50 minutes and cooled to −30° C. Methanol (40.00 mL) was added and the resulting mixture was gradually warmed to room temperature and concentrated to give the crude alcohol.
(S)-4-Methyl-indan-1-ylamine: (R)-4-Methyl-indan-1-ol (34.20 mmol, crude taken from the previous step) was dissolved in toluene and cooled to 0° C., diphenylphosphoryl azide (8.80 mL, 40.83 mmol) was added. The resulting mixture was stirred for a few minutes and DBU (5.20 mL, 34.77 mmol) was added slowly. After stirring for 14 hours, the reaction mixture was diluted with toluene and washed with H2O (3×50 mL), brine (1×50 mL), dried over MgSO4 and concentrated. Purification by column chromatography using hexane:EtOAc (4:1) as eluant gave the desired azido compound. This azido compound was then dissolved in THF:H2O (3:1), Ph3P (7.80 g, 29.74 mmol) was added, followed by KOH (2.00 g, 35.64 mmol). The resulting mixture was stirred for 14 hours. The reaction mixture was then diluted with H2O and slowly acidified with HCl and the aqueous layer was washed with Et2O (3×50 mL). The aqueous layer was then basified with NaOH (pH 14) and extracted with Et2O (3×50 mL). The combined organic extracts were washed with H2O (1×25 mL), brine (1×25 mL), dried over K2CO3 and concentrated to give the desired indan amine.
(S)-(+)-1-(2-Fluoro-ethyl)-3-(4-methyl-indan-1-yl)-cyanoguanidine: The title compound was obtained from (S)-4-methyl-indan-1-ylamine (3.00 g, 20.38 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (2.00 g, 9.66 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.83-1.96 (m, 1H), 2.2 (s, 3H), 2.34-2.49 (m, 1H), 2.61-2.74 (m, 1H), 2.83-2.95 (m, 1H), 3.42-3.58 (m, 2H), 4.4 (t, J=5.3 Hz, 1H), 4.6 (t, J=5.0 Hz, 1H), 5.3 (q, J=7.9 Hz, 1H), 7.01-7.09 (m, 2H), 7.1 (t, J=7.3 Hz, 1H), 7.19-7.28 (m, 2H). 13C NMR (75 MHz, DMSO-d6)  19.1, 28.8, 33.0, 42.2 (d, J=20.7 Hz), 57.4, 82.8 (d, J=166.4 Hz), 118.4, 121.9, 127.3, 128.9, 134.2, 142.4, 143.5, 159.9.
General Procedure D for the Synthesis of Fluoroethyl Substituted (1,2,3,4-Tetrahydronaphthalen-1-yl)cyanoguanidines




To a solution of 3-(2-substituted-phenyl)-propan-1-ol in CH2Cl2 at 0° C. was added Et3N (2.0 eq) and MsCl (1.5 eq). The resulting mixture was stirred for 1 hour, then washed with H2O (3×100 mL), brine (1×150 mL), dried over MgSO4 and concentrated. The residue was dissolved in DMF and KCN (2.0 eq) was added and the resulting mixture was stirred at 75° C. for 14 hours. After cooling to room temperature, the reaction mixture was quenched into water and extracted with Et2O (3×300 mL). The combined organic extracts were washed with H2O (2×200 mL), brine (1×200 mL), dried over MgSO4 and concentrated to give 4-(2-substituted-phenyl)-butyronitrile. This crude butyronitrile was taken up in ethanol and KOH (2 eq) was added. The resulting mixture was refluxed for 14 hours. The reaction mixture was cooled to room temperature, diluted with water and washed with Et2O (2×150 mL). The aqueous layer was acidified with concentrated HCl and the resulting solution was extracted with Et2O (3×300 mL). The combined organic extracts were washed with H2O (2×200 mL), brine (1×200 mL), dried over MgSO4 and concentrated to give 4-(2-substituted-phenyl)-butyric acid. The crude acid was then dissolved in benzene and SOCl2 (1.5 eq) was added and the reaction mixture was refluxed for 4 hours. After cooling to room temperature, the reaction mixture was concentrated and the residue was taken up in CH2Cl2 and cooled to 0° C. AlCl3 (1.1 eq) was added and the resulting mixture was stirred for 14 hours. The reaction mixture was quenched with HCl, washed with H2O (2×200 mL), brine (1×200 mL), dried over MgSO4 and concentrated to give 5-substituted-3,4-dihydro-2H-naphthalen-1-one. This ketone was thus converted into the desired fluoroethyl cyanoguanidine according to general procedure B.




Synthesis of 1-(2-fluoro-ethyl)-3-(5-methyl-1,2,3,4-tetrahydro-naphthalen-1-yl)-cyanoguanidine




The desired starting 3-o-tolylpropan-1-ol was prepared from the commercially available 3-o-tolyl-acrylic acid using the protocol described in the scheme above. The title cyanoguanidine was thus obtained from this alcohol according to general procedure D. The intermediates 3-o-tolylpropan-1-ol, 4-o-tolyl-butyronitrile, 5-methyl-3,4-dihydro-2H-naphthalen-1-one and 5-methyl-1,2,3,4-tetrahydro-naphthalen-1-ylamine were separated and characterized.
3-o-Tolyl-propan-1-olix: 3-o-Tolyl-acrylic acid (10.00 g, 62.00 mmol) in THF was mixed with Rh/Al2O3 (800 mg) and hydrogenated at 50 psi for 6 hours. The resulting mixture was filtered through a pad of celite and the filtrate was concentrated. The residue was dissolved in THF and cooled to 0° C. LAH (62.00 mL, 1.0 M in THF, 62.00 mmol) was added and the reaction mixture was stirred for 14 hours. The resulting mixture was quenched with NaOH and extracted with Et2O (3×250 mL). The combined organic extracts were washed with H2O (3×150 mL), brine (1×150 mL), dried over MgSO4 and concentrated to give the title alcohol. ix Stipanovic, B.; Pines, H. J. Org. Chem. 1969, 34, 2106-2113.
4-o-Tolyl-butyronitrilex: The title compound was obtained from 3-o-tolyl-propan-1-ol (taken from the previous step), Et3N (17.20 mL, 0.12 mol), MsCl (7.60 mL, 98.19 mmol) and KCN (8.00 g, 0.12 mol) according to the protocols as outlined in general procedure D. x Staab, Heinz A.; Nikolic, Susanne; Krieger, Claus Eur. J. Org. Chem. 1999, 6, 1459-1470.
5-Methyl-3,4-dihydro-2H-naphthalen-1-onexi: The title compound was obtained from 4-o-tolyl-butyronitrile (taken from the previous step), KOH (7.00 g, 124.75 mmol), SOCl2 (7.00 mL, 95.96 mmol) and AlCl3 (9.00 g, 67.50 mmol) according to the protocols as outlined in general procedure D. xi Zhang, Xiaoyan; Angeles, Joseph E. De Los; He, Mei-Ying; Dalton, James T.; Shams, Gamal; et al. J. Med. Chem. 1997, 40, 3014-3024.
5-Methyl-1,2,3,4-tetrahydro-naphthalen-1-ylamine: The title amine was obtained from 5-methyl-3,4-dihydro-2H-naphthalen-1-one (7.00 g, 43.80 mmol), NaBH3CN (19.30 g, 0.31 mol) and NH4OAc (101.20 g, 1.31 mol) according to the protocols as outlined in general procedure B.
1-(2-Fluoro-ethyl)-3-(5-methyl-1,2,3,4-tetrahydro-naphthalen-1-yl)-cyanoguanidine: The title compound was obtained from 5-methyl-1,2,3,4-tetrahydro-naphthalen-1-ylamine (1.50 g, 9.30 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.61-2.01 (m, 4H), 2.1 (s, 3H), 2.48-2.62 (m, 2H), 3.41-3.57 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.5 (t, J=5.0 Hz, 1H), 4.90-5.03 (m, 1H), 7.00-7.11 (m, 3H), 7.14-7.23 (m, 2H). 13C NMR (75 MHz, DMSO-d6)  19.9, 20.4, 26.7, 29.9, 42.2 (d, J=20.7 Hz), 50.6, 82.8 (d, J=166.4 Hz), 118.5, 126.1, 126.3, 128.9, 136.4, 136.6, 137.4, 159.6.




Synthesis of 1-(5-chloro-1,2,3,4-tetrahydro-naphthalen-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine




The desired starting 3-(2-chlorophenyl)propan-1-ol was prepared from the commercially available 3-(2-chlorophenyl)-acrylic acid using the protocol described in the scheme above. The title cyanoguanidine was thus obtained from this alcohol according to general procedure D. The intermediates 3-(2-chlorophenyl)propan-1-ol, 4-(2-chlorophenyl)butyronitrile, 5-chloro-3,4-dihydro-2H-naphthalen-1-one and 5-chloro-1,2,3,4-tetrahydro-naphthalen-1-ylamine were separated and characterized.
3-(2-Chloro-phenyl)-propan-1-olxii: 3-(2-Chloro-phenyl)-acrylic acid (10.00 g, 55.00 mmol) in THF was mixed with Rh/Al2O3 (800 mg) and hydrogenated at 50 psi for 6 hours. The resulting mixture was filtered through a pad of celite and the filtrate was concentrated. The residue was dissolved in THF and cooled to 0° C. LAH (55.00 mL, 1.0 M in THF, 55.00 mmol) was added and the reaction mixture was stirred for 14 hours. The resulting mixture was quenched with NaOH and extracted with Et2O (3×250 mL). The combined organic extracts were washed with H2O (3×150 mL), brine (1×150 mL), dried over MgSO4 and concentrated to give the title alcohol. xii Baddar et al. J. Chem. Soc. 1959, 1027-1029.
4-(2-Chloro-phenyl)-butyronitrilexiii: The title compound was obtained from 3-(2-chloro-phenyl)-propan-1-ol (taken from the previous step without further purification), Et3N (15.00 mL, 0.11 mol), MsCl (7.00 mL, 90.44 mmol) and KCN (7.02 g, 0.11 mol) according to the protocols as outlined in procedure D. xiii Bunnett, J. F.; Skorcz, J. A. J. Org. Chem. 1962, 27, 3836-3843.
5-Chloro-3,4-dihydro-2H-naphthalen-1-one14: The title compound was obtained from 4-(2-chloro-phenyl)-butyronitrile (taken from the previous step without further purification), KOH (4.00 g, 71.29 mmol), SOCl2 (4.00 mL, 54.84 mmol) and AlCl3 (5.30 g, 39.75 mmol) according to the protocols as outlined in procedure D.
5-Chloro-1,2,3,4-tetrahydro-naphthalen-1-ylaminexiv: The title compound was obtained from 5-Chloro-3,4-dihydro-2H-naphthalen-1-one (6.00 g, 33.30 mmol), NaBH3CN (15.00 g, 0.24 mol) and NH4OAc (77.00 g, 1.00 mol) according to the protocols as outlined in procedure B. xiv Kuiban et al. J. Gen. Chem. USSR (Engl. Transl.) 1964, 34, 1592; Zh. Obshch. Khim. 1964, 34, 1581.
1-(5-Chloro-1,2,3,4-tetrahydro-naphthalen-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 5-chloro-1,2,3,4-tetrahydro-naphthalen-1-ylamine (1.60 g, 8.80 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.49-2.14 (m, 4H), 2.7 (br s, 2H), 3.44-3.59 (m, 2H), 4.36-4.46 (m, 1H), 4.51-4.61 (m, 1H), 5.0 (br s, 1H), 7.15-7.24 (m, 2H), 7.27-7.38 (m, 3H). 13C NMR (75 MHz, DMSO-d6) □ 20.0, 27.5, 29.5, 42.2 (d, J=20.7 Hz), 50.3, 82.8 (d, J=166.4 Hz), 118.5, 127.5, 127.7, 128.2, 133.9, 135.7, 140.3, 159.6.




Synthesis of 1-(5-ethyl-1,2,3,4-tetrahydro-naphthalen-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine




The desired starting 3-(2-ethylphenyl)propan-1-ol was prepared from the commercially available 1-bromo-2-ethylbenzene using the protocol described in the scheme above. The title cyanoguanidine was thus obtained from this alcohol according to general procedure D. The intermediates 2-ethylbenzaldehyde, 3-(2-ethylphenyl)acrylic acid, 3-(2-ethylphenyl)propan-1-ol, 4-(2-ethylphenyl)butyronitrile, 5-ethyl-3,4-dihydro-2H-naphthalen-1-one and 5-ethyl-1,2,3,4-tetrahydro-naphthalen-1-ylamine were separated and characterized.
2-Ethyl-benzaldehyde8: 1-Bromo-2-ethyl-benzene (5.00 g, 27.00 mmol), Mg (4.00 g, 164.54 mmol) and a catalytic amount of I2 in THF were refluxed for 2 hours. The reaction mixture was cooled to 0° C., DMF (10.00 mL, 129.17 mmol) was added. The resulting reaction mixture was stirred for 30 minutes, then was quenched with 10% HCl. The resulting solution was extracted with Et2O (3×200 mL) and the combined organic extracts were washed with H2O (2×200 mL) and brine (1×200 mL), then dried over MgSO4 and concentrated to give the desired title benzaldehyde.
3-(2-Ethyl-phenyl)-acrylic acid9: 2-Ethyl-benzaldehyde (18.40 g, 0.14 mol) and malonic acid (28.00 g, 0.27 mol) were mixed in pyridine, then 10.00 mL of piperidine was added. The resulting mixture was slowly refluxed for 3 hours. After cooling to room temperature, the reaction mixture was quenched into cold water, acidified to pH<1 and the resulting solid was filtered, washed with water and dried under vacuum to give the desired title acid.
3-(2-Ethyl-phenyl)-propan-1-ol: 3-(2-Ethyl-phenyl)-acrylic acid (17.00 g, 96.60 mmol) in THF was mixed with Pd/C (1.50 g) and hydrogenated at 50 psi for 6 hours. The resulting mixture was filtered through a pad of celite and the filtrate was concentrated. The residue was dissolved in THF and cooled to 0° C. LAH (100.00 mL, 1.0 M in THF, 0.10 mol) was added and the reaction mixture was stirred for 14 hours. The resulting mixture was quenched with NaOH and extracted with Et2O (3×250 mL). The combined organic extracts were washed with H2O (3×150 mL) and brine (1×150 mL), then dried over MgSO4 and concentrated to give the title alcohol.
4-(2-Ethyl-phenyl)-butyronitrile: The title compound was obtained from 3-(2-ethyl-phenyl)-propan-1-ol (taken from the previous step without further purification), Et3N (13.00 mL, 93.27 mmol), MsCl (5.50 mL, 71.06 mmol) and KCN (6.50 g, 99.82 mmol) according to the protocols as outlined in general procedure D.
5-Ethyl-3,4-dihydro-2H-naphthalen-1-onexv: The title compound was obtained from of 3-(2-ethyl-phenyl)-propionitrile (taken from the previous step without further purification), KOH (4.00 g, 71.29 mmol), SOCl2 (4.00 mL, 54.84 mmol) and AlCl3 (5.40 g, 40.50 mmol) according to the protocols as outlined in general procedure D. xv Burnham, J. W. et al. J. Org. Chem. 1974, 39, 1416-1420.
5-Ethyl-1,2,3,4-tetrahydro-naphthalen-1-ylamine: The title compound was obtained from 5-ethyl-3,4-dihydro-2H-naphthalen-1-one (4.50 g, 25.90 mmol), NaBH3CN (11.40 g, 0.18 mol) and NH4OAc (60.00 g, 0.78 mol) according to the protocols as outlined in general procedure B.
1-(5-Ethyl-1,2,3,4-tetrahydro-naphthalen-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 5-ethyl-1,2,3,4-tetrahydro-naphthalen-1-ylamine (1.60 g, 9.20 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) □ 1.2 (t, J=7.3 Hz, 3H), 1.68-1.80 (m, 2H), 1.84-1.95 (m, 2H), 2.5 (q, J=7.6 Hz, 2H), 2.7 (t, J=5.9, 5.3 Hz, 2H), 3.42-3.57 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.5 (t, J=5.0 Hz, 1H), 4.90-5.04 (m, 1H), 7.01-7.13 (m, 3H), 7.15-7.24 (m, 2H). 13C NMR (75 MHz, DMSO-d6) □ 14.9, 20.6, 25.8, 26.0, 30.0, 42.2 (d, J=20.7 Hz), 50.8, 82.8 (d, J=166.4 Hz), 118.5, 126.2, 126.3, 127.2, 135.7, 137.6, 142.3, 159.6.




Synthesis of 1-(2-fluoro-ethyl)-3-(5-fluoro-1,2,3,4-tetrahydro-naphthalen-1-yl)-cyanoguanidine




3-(2-Fluoro-phenyl)-propionitrile: To a solution of 2-(2-fluoro-phenyl)-ethanol (10.00 g, 71.50 mmol) in CH2Cl2 at 0° C. was added Et3N (20.00 mL, 0.14 mol) followed by MsCl (19.00 mL, 0.25 mol). The resulting mixture was stirred for 1 hour, then washed with H2O (3×100 mL) and brine (1×150 mL), dried over MgSO4 and concentrated. The residue was dissolved in DMF and KCN (9.30 g, 0.14 mol) was added. The resulting mixture was stirred at 75° C. for 14 hours. After cooling to room temperature, the reaction mixture was quenched into water and extracted with Et2O (3×300 mL). The combined organic extracts were washed with H2O (2×200 mL), brine (1×200 mL), dried over MgSO4 and concentrated to give the title compound.
3-(2-Fluoro-phenyl)-propan-1-ol: 3-(2-Fluoro-phenyl)-propionitrile (taken from the previous step without further purification) was dissolved in ethanol and KOH (8.00 g, 0.14 mol) was added. The resulting mixture was refluxed for 14 hours. After cooling to room temperature, the reaction mixture was diluted with water and washed with Et2O (2×150 mL). The aqueous layer was acidified with concentrated HCl, then extracted with Et2O (3×300 mL). The combined organic phases were washed with H2O (2×200 mL), and brine (1×200 mL), then dried over MgSO4 and concentrated to give the desired (3-chloro-2-fluoro-phenyl)-acetic acid. The acid was then dissolved in THF and iodoethane (12.00 mL, 0.15 mol) was added. The resulting mixture was refluxed for 2 hours. After cooling to room temperature, the reaction mixture was extracted with Et2O (3×300 mL) and the combined organic extracts were washed with H2O (2×200 mL) and brine (1×200 mL), then dried over MgSO4 and concentrated to give the desired 3-(2-fluoro-phenyl)-propionic acid ethyl ester. This ethyl ester was then dissolved in THF and cooled to 0° C. LAH (72.00 mL, 1.0 M in THF, 72.00 mmol) was added. The resulting reaction mixture was stirred for 14 hours, then quenched with NaOH. The resulting mixture was extracted with Et2O (3×250 mL) and the combined organic extracts were washed with H2O (3×150 mL) and brine (1×150 mL), then dried over MgSO4 and concentrated to give the desired title alcohol.
4-(2-Fluoro-phenyl)-butyronitrile: The title compound was obtained from 3-(2-fluoro-phenyl)-propan-1-ol (taken from the previous step without further purification), Et3N (20.00 mL, 143.63 mmol), MsCl (9.00 mL, 0.12 mol) and KCN (9.30 g, 0.14 mol) according to the protocols as outlined in general procedure D.
5-Fluoro-3,4-dihydro-2H-naphthalen-1-one: The title compound was obtained from 3-(2-Fluoro-phenyl)-butyronitrile (taken from the previous step without further purification), KOH (8.00 g, 0.14 mol), SOCl2 (7.00 mL, 95.97 mmol) and AlCl3 (9.50 g, 71.25 mmol) according to general procedure D.
5-Fluoro-1,2,3,4-tetrahydro-naphthalen-1-ylamine: The title amine was obtained from 5-fluoro-3,4-dihydro-2H-naphthalen-1-one (4.50 g, 27.40 mmol), NaBH3CN (12.00 g, 0.19 mol) and NH4OAc (63.40 g, 0.82 mol) according to the protocols as outlined in general procedure D.
1-(2-Fluoro-ethyl)-3-(5-fluoro-1,2,3,4-tetrahydro-naphthalen-1-yl)-cyanoguanidine: The title compound was obtained from 5-fluoro-1,2,3,4-tetrahydro-naphthalen-1-ylamine (1.50 g, 9.10 mmole) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.00 g, 4.83 mmol) in CH3CN according to the protocols as outlined in general procedure A above. Spectroscopic data: 1H NMR (300 MHz, DMSO-d) δ 1.68-1.82 (m, 2H), 1.85-1.96 (m, 2H), 2.58-2.73 (m, 2H), 3.42-3.57 (m, 2H), 4.4 (t, J=5.0 Hz, 1H), 4.5 (t, J=4.7, 4.1 Hz, 1H), 4.92-5.05 (m, 1H), 7.1 (t, J=9.1, 7.9 Hz, 2H), 7.18-7.34 (m, 3H). 13C NMR (75 MHz, DMSO-d6) δ 19.8, 22.1, 29.8, 42.2 (d, J=20.7 Hz), 50.0, 82.8 (d, J=166.4 Hz), 113.6 (d, J=21.8 Hz), 118.4, 124.2, 125.4 (d, J=18.4 Hz), 127.5 (d, J=9.2 Hz), 140.4 (d, J=4.6 Hz), 160.6 (d, J=242.1 Hz), 159.7.
General Procedure E for the Synthesis of Fluoroethyl Indan Cyanoguanidines




A solution of SOCl2 (1.5 eq) and substituted benzoic acid in benzene was refluxed until no more gas evolution was observed. After cooling to room temperature the reaction mixture was concentrated. The concentrate was taken up in dichloroethane and added to a suspension of AlCl3 (1.0 eq) in dichloroethane at 10-20° C. Ethylene was bubbled for 4 hours, then the resulting mixture was stirred for 14 hours and quenched into 4 N HCl. The resulting layers were separated and the aqueous layer was extracted with Et2O (3×250 mL). The combined organic extracts were washed with H2O (3×100 mL), saturated NaHCO3 (3×100 mL) and brine (1×100 mL), then dried over MgSO4 and concentrated.
For halogen-containing analogs, the following cyclization procedure was followed: The concentrate containing crude halo substituted phenylpropan-1-one was added to a slurry of AlCl3 (10.0 eq) and NaCl (6.0 eq) at 130° C. The resulting mixture was stirred at 180° C. for 2 hours, then cooled to room temperature and slowly quenched with ice, followed by concentrated HCl. The resulting mixture was extracted with CH2Cl2 (3×300 mL) and the combined extracts were concentrated and purified by column chromatography using hexane:EtOAc (4:1) as eluant to give the desired pure indanone.
For alkyl and halogen-containing analogs, the following cyclization procedure was followed: Concentrated sulfuric acid was added to the concentrate containing crude halo and alkyl substituted phenylpropan-1-one and the mixture was stirred at 85° C. for 1 hour. After cooling to room temperature, the reaction mixture was quenched into ice-water. The resulting mixture was extracted with Et2O (3×200 mL) and the combined extracts were washed with H2O (3×200 mL), saturated NaHCO3 (3×200 mL) and brine (1×100 mL), then dried over MgSO4 and concentrated. The pure indanone was obtained after column chromatography using hexane:EtOAc (4:1) as eluant. The desired final cyanoguanidine was thus obtained from this indanone according to the protocols described in general procedure B.




Synthesis of 1-(7-bromo-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine
The title cyanoguanidine was obtained from the commercially available 2-bromobenzoic acid according to general procedure E. The intermediates 7-bromo-1-one and 7-bromoindan-1-ylamine were separated and characterized.
7-Bromo-1-indanone: 9.68 g (31%) of the title amine was obtained from 2-bromo-benzoic acid (30.00 g, 0.15 mol), SOCl2 (16.50 mL, 0.23 mol), AlCl3 (20.00 g, 0.15 mol), an additional AlCl3 (200.00 g, 1.50 mol) and NaCl (52.30 g, 0.89 mol) according to the protocols as outlined in general procedure E. Spectroscopic data: 1H NMR (300 MHz, CDCl3) □ 2.69-2.79 (m, 2H), 3.04-3.14 (m, 2H), 7.35-7.45 (m, 2H), 7.49-7.55 (m, 1H).
7-Bromo-indan-1-ylamine: 4.84 g of The crude amine (used in the next step without further purification) was obtained from 7-bromo-1-indanone (8.00 g, 38.00 mmol), NaBH3CN (16.70 g, 0.27 mol) and NH4OAc (88.00 g, 1.14 mol) according to the protocols as outlined in general procedure B.
1-(7-Bromo-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 7-bromo-indan-1-ylamine (2.42 g, 11.40 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.20 g, 5.79 mmol) according to the protocols as outlined in general procedure A. Spectroscopic data: 1H NMR (300 MHz, DMSO-d6)  1.86-1.99 (m, 1H), 2.33-2.46 (m, 1H), 2.78-2.91 (m, 1H), 3.05-3.19 (m, 1H), 3.39-3.55 (m, 2H), 4.4 (t, 1H, J=5.3 Hz), 4.5 (t, 1H, J=5.0 Hz), 5.24-5.36 (m, 1H), 7.2 (t, 2H, J=7.6 Hz), 7.27-7.36 (m, 2H), 7.4 (d, 1H, J=7.9 Hz). 13C NMR (75 MHz, DMSO-d6)  31.2, 33.3, 42.1 (d, J=20.7 Hz), 58.1, 82.6 (d, J=166.4 Hz), 118.4, 120.5, 124.7, 130.7, 130.9, 141.7, 147.9, 159.3.




Synthesis of 2-(2-fluoro-ethyl)-3-(7-fluoro-indan-1-yl)-cyanoguanidine
The title cyanoguanidine was obtained from the commercially available 2-fluorobenzoic acid according to general procedure E. The intermediates 7-fluoro-1-one and 7-fluoroindan-1-ylamine were separated and characterized.
7-Fluoro-1-indanone: 6.85 g (32%) of the title indanone was obtained from 2-fluoro-benzoic acid (20.00 g, 0.14 mol), SOCl2 (15.60 mL, 0.21 mol), AlCl3 (19.00 g, 0.14 mol), an additional AlCl3 (285.50 g, 2.14 mol) and NaCl (75.10 g, 1.29 mol) according to the protocols as outlined in general procedure E. Spectroscopic data: 1H NMR (300 MHz, CDCl3) □ 2.67-2.80 (m, 2H), 3.2 (t, 2H, J=5.9 Hz), 7.0 (t, 1H, J=8.5 Hz), 7.3 (d, 1H, J=7.6 Hz), 7.6 (m, 1H).
7-Fluoro-indan-1-ylamine: The title compound was obtained from 7-fluoro-1-indanone (5.82 g, 39.00 mmol), NaBH3CN (17.10 g, 0.27 mol) and NH4OAc (90.00 g, 1.17 mol) according to the protocols as outlined in general procedure B. Spectroscopic data: 1H NMR (300 MHz, CDCl3) □ 1.69-2.25 (m, 3H), 2.40-2.54 (m, 1H), 2.77-2.92 (m, 1H), 3.00-3.15 (m, 1H), 4.62 (t, J=7.04, 6.16 Hz, 1H), 6.77-6.90 (m, 1H), 7.00 (t, J=8.21 Hz, 1H), 7.10-7.22 (m, 1H).
1-(2-Fluoro-ethyl)-3-(7-fluoro-indan-1-yl)-cyanoguanidine: The title compound was obtained from A solution of 7-fluoro-indan-1-ylamine (2.43 g, 16.10 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (1.70 g, 8.20 mmol) according to the protocols as outlined in general procedure A. Spectroscopic data: 1H NMR (300 MHz, DMSO-d6)  1.88-2.01 (m, 1H), 2.38-2.51 (m, 1H), 2.75-2.87 (m, 1H), 2.97-3.10 (m, 1H), 3.40-3.55 (m, 2H), 4.4 (t, 1H, J=5.0 Hz), 4.5 (t, 1H, J=5.3 Hz), 5.5 (q, 1H, J=7.6 Hz), 7.0 (t, 1H, J=9.1 Hz), 7.1 (d, 1H, J=7.3 Hz), 7.19-7.34 (m, 2H), 7.4 (d, 1H, J=8.5 Hz). 13C NMR (75 MHz, DMSO-d6)  □ 0.8, 33.9, 42.2 (d, J=21.8 Hz), 54.9, 82.5 (d, J=166.4 Hz), 113.7 (d, J=20.7 Hz), 118.3, 121.4 (d, J=3.4 Hz), 129.0 (d, J=14.9 Hz), 131.0 (d, J=8.0 Hz), 148.0 (d, J=4.6 Hz), 159.3, 160.0 (d, J=246H).




Synthesis of 1-(7-chloro-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine
The title cyanoguanidine was obtained from the commercially available 2-chlorobenzoic acid according to general procedure E. The intermediates 7-chloro-1-one and 7-chloroindan-1-ylamine were separated and characterized.
7-Chloro-1-indanone: 4.13 g (31%) of the title indanone was obtained from 2-chloro-benzoic acid (10.0 g, 64.00 mmol), SOCl2 (7.00 mL, 95.97 mmol), AlCl3 (8.50 g, 63.75 mmol), an additional AlCl3 (85.20 g, 0.64 mol) and NaCl (22.40 g, 0.38 mol) according to the protocols as outlined in general procedure E. Spectroscopic data: 1H NMR (300 MHz, CDCl3) □ 2.65-2.75 (m, 2H), 3.1 (t, 2H, J=6.7, 5.6 Hz), 7.3 (d, 1H, J=7.6 Hz), 7.4 (d, 1H, J=7.6 Hz), 7.5 (t, 1H, J=7.6 Hz).
7-Chloro-indan-1-ylamine: 1.00 g of the crude title amine (used in the next step without further purification) was obtained from 7-chloro-1-indanone (4.13 g, 25.00 mmol), NaBH3CN (11.00 g, 0.17 mol) and NH4OAc (57.4 g, 0.74 mol) according to the protocols as outlined in general procedure B. Spectroscopic data: 1H NMR (300 MHz, CDCl3)  1.7 (br s, 2H), 1.82-1.92 (m, 1H), 2.37-2.51 (m, 1H), 2.79-2.94 (m, 1H), 3.07-3.19 (m, 1H), 4.48-4.59 (m, 1H), 7.07-7.16 (m, 3H).
1-(7-Chloro-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 7-chloro-indan-1-ylamine (1.00 g, 6.00 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (660 mg, 3.19 mmol) according to the protocols as outlined in general procedure A. Spectroscopic data: 1H NMR (300 MHz, DMSO-d6)  1.86-1.98 (m, 1H), 2.35-2.47 (m, 1H), 2.76-2.89 (m, 1H), 3.03-3.16 (m, 1H), 3.39-3.55 (m, 2H), 4.4 (t, 1H, J=5.3 Hz), 4.5 (t, 1H, J=5.0 Hz), 5.34-5.46 (m, 1H), 7.19-7.33 (m, 4H), 7.4 (d, 1H, J=8.5 Hz). 13C NMR (75 MHz, DMSO-d6)  131.0, 33.4, 42.2 (d, J=20.7 Hz), 56.7, 82.5 (d, J=166.4 Hz), 118.4, 124.2, 127.7, 130.7, 131.2, 139.9, 147.7, 159.3.




Synthesis of N-(6,7-difluoro-indan-1-yl)-N′-(2-fluoro-ethyl)-cyanoguanidine
The title cyanoguanidine was obtained from the commercially available 2-3-difluorobenzoic acid according to general procedure E. The intermediates 6,7-difluoro-1-one and 6,7-difluoroindan-1-ylamine were separated and characterized.
Synthesis of 6,7-difluoro-1-indanone: A solution of 2,3-difluoro-benzoic acid (10.30 g, 65.14 mmol), SOCl2 (7.20 mL, 98.71 mmol), AlCl3 (8.70 g, 65.25 mmol), an additional AlCl3 (87.0 g, 0.65 mol) and NaCl (23.00 g, 0.39 mol) was reacted according to the protocols as outlined in general procedure E to give 6.00 g (55%) of the title compound. Spectroscopic data: 1H NMR (300 MHz, CDCl3) □ 2.73-2.80 (m, 2H), 3.09-3.16 (m, 2H), 7.11-7.23 (m, 1H), 7.35-7.46 (m, 1H).
6,7-Difluoro-indan-1-ylamine: A solution of 6,7-difluoro-1-indanone (6.00 g, 35.70 mmol), NaBH3CN (15.70 g, 0.25 mol) and NH4OAc (82.60 g, 1.07 mol) in isopropanol was reacted according to the protocols as outlined in general procedure B to give 3.00 g of the crude title compound, which was used in the next step without further purification. Spectroscopic data: 1H NMR (300 MHz, CDCl3) □ 1.7 (br s, 2H), 1.78-1.90 (m, 1H), 2.44-2.57 (m, 1H), 2.72-2.87 (m, 1H), 2.95-3.09 (m, 1H), 4.7 (t, 1H, J=6.7 Hz), 6.86-7.00 (m, 2H).
1-(6,7-Difluoro-indan-1-yl)-3-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained 6,7-difluoro-indan-1-ylamine (1.50 g, 9.00 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (930 mg, 4.45 mmol) according to the protocols as outlined in general procedure A. Spectroscopic data: 1H NMR (300 MHz, DMSO-d6) □ 1.92-2.05 (m, 1H), 2.41-2.54 (m, 1H), 2.71-2.85 (m, 1H), 2.92-3.05 (m, 1H), 3.40-3.55 (m, 2H), 4.4 (t, 1H, J=5.6 Hz), 4.5 (t, 1H, J=5.0 Hz), 5.5 (q, 1H, J=7.3 Hz), 7.02-7.12 (m, 1H), 7.22-7.35 (m, 2H), 7.5 (d, 1H, J=8.2 Hz). 13C NMR (75 MHz, DMSO-d6)  30.3, 34.6, 42.2 (d, J=20.7 Hz), 55.3, 82.5 (d, J=166.4 Hz), 117.8 (d, J=18.4 Hz), 118.2, 121.2 (dd, J=6.9, 3.4 Hz), 131.6 (d, J=10.3 Hz), 142.5, 147.3 (dd, J=248.2, 11.5 Hz), 149.0 (dd, J=242, 13.8 Hz), 159.4.




Synthesis of 1-(1,2-diphenyl-ethyl)3′-(2-fluoro-ethyl)-cyanoguanidine
The title compound was obtained from the commercially available 1,2-diphenyl-ethylamine according to general procedure A described above.
1-(1,2-Diphenyl-ethyl)3′-(2-fluoro-ethyl)-cyanoguanidine: The title compound was obtained from 1,2-diphenyl-ethylamine (586 mg, 2.97 mmol) and 1-(2-fluoro-ethyl)-2-phenyl-3-cyanoisourea (560 mg, 2.70 mmol) according to the protocols as outlined in general procedure A. Spectroscopic data: 1H NMR (300 MHz, CDCl3) □ ppm 3.11 (d, J=7.04 Hz, 2H) 3.29-3.45 (m, 2H) 4.25 (ddd, J=8.94, 4.40, 4.25 Hz, 1H) 4.34-4.47 (m, 1H) 4.68 (q, J=6.64 Hz, 1H) 4.94 (br s, 1H) 5.86 (d, J=4.40 Hz, 1H) 7.08 (d, J=7.04 Hz, 2H) 7.22 (d, J=6.74 Hz, 2H) 7.26-7.30 (m, 3H) 7.35 (t, J=7.33 Hz, 3H).

## Claims

1. A compound having a formula




wherein a dashed line indicates the presence or absence of a bond;
n is 0 or 1;
A is substituted or unsubstituted phenyl;
B is alkyl having 1, 2, 3, or 4 carbon atoms; or
B is H or substituted or unsubstituted phenyl and the dashed line is not a covalent bond.

2. The compound of claim 1 wherein A is phenyl substituted with 0, 1, 2, 3, or 4 substituents, wherein the substituents are independently alkyl having from 1 to 4 carbon atoms or a halogen.

3. The compound of claim 2 wherein the substituents are independently methyl, ethyl, F, Cl, or Br.

4. The compound of claim 1 wherein A is unsubstituted phenyl.

5. The compound of claim 1 having a formula




wherein m is 0 or 1; and
Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, amine having from 1 to 6 carbon atoms, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.

6. The compound of claim 5 having a formula

7. The compound of claim 1 having a formula

8. The compound of claim 1 having a formula




wherein m is 0 or 1; and
Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, amine having from 1 to 6 carbon atoms, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.

9. The compound of claim 8 having a formula

10. The compound of claim 8 having a formula

11. The compound of claim 1 having a formula




wherein Rg, Rh, Ri, and Rj are independently H, alkyl having from 1 to 6 carbon atoms, halogen, CN, CH2CN, amine having from 1 to 6 carbon atoms, hydroxyalkyl having from 1 to 6 carbon atoms, acyl having from 1 to 6 carbon atoms, O-alkyl having from 1 to 6 carbon atoms, amine substituents having from 0 to 6 carbon atoms, or S-alkyl having from 1 to 6 carbon atoms.

12. The compound of claim 1 having a formula




wherein A is substituted or unsubstituted phenyl; and
B is substituted or unsubstituted phenyl.

13. The compound of claim 1 selected from