DETAILED DESCRIPTION OF THE INVENTION

[0092] In general, the invention features compounds of Formula I: 5

[0093] wherein

[0094] ---[b] is a single or double bond;

[0095] Each X, Y, and Z is independently selected from H, —OH, —O-alkyl, and —O-substituted alkyl;

[0096] R₁ is selected from H, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, and aryl;

[0097] R₂ is selected from H, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, and aryl;

[0098] R₃ is selected from H, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, and -A-E-R₈;

[0099] A is selected from alkyl and substituted alkyl;

[0100] E is selected from —N(R₁₀)C(O)—, —C(O)N(R₁₀)—, —N(R₁₀)C(S)—, —C(S)N(R₁₀)—, —S(O)N(R₁₀)—, —N(R₁₀) S(O)—, —S(O)₂N(R₁₀)—, and —N(R₁₀)S(O)₂—;

[0101] Each R₄, R₅, R₆, and R₇ is independently selected from H, halogen, aryl, —CN, —NO₂, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, —OR₉, —NH₂, —C(O)NH₂, —C(S)NH₂, and —S(O)_naryl, provided that one of R₄, R₅, R₆, and R₇ is —S(O)_naryl, and that at least one of R₄, R₅, R₆, and R₇ is H;

[0102] n is 0, 1, or 2;

[0103] Each R₈, R₉, and R₁₀ is independently selected from H, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, and aryl;

[0104] Aryl is phenyl, naphthyl, hetereoaromatic, substituted phenyl, substituted naphthyl, or substituted heteroaromatic;

[0105] Heteroaromatic is a 5-, 6-, 9-, or 10-member heteroaromatic mono- or bicyclic ring system containing 1-3 hetero atoms selected from N, O, and S;

[0106] Substituted phenyl is phenyl having 1-3 substituents independently selected from halogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, —OR₁₁, —SR₁₁, —CN, —NO₂, —N₃, —N(R₁₁)₂, —C(O)N(R₁₁)₂, —C(S)N(R₁₁)₂, tetrazole, triazole, amidine, guanidine, thioguanidine, cyanoguanidine, phenyl, naphthyl, and heteroaromatic, provided that any of the phenyl, naphthyl, or heteroaromatic is optionally substituted with up to 3 substituents independently selected from halogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, —OR₁₂, —SR₁₂, —CN, —NO₂, —N₃, —N(R₁₁)₂, —C(O)N(R₁₁)₂, and —C(S)N(R₁₁)₂;

[0107] Substituted naphthyl is naphthyl having 1-6 substituents independently selected from halogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, —OR₁₁, —SR₁₁, —CN, —NO₂, —N₃, —N(R₁₁)₂, —C(O)N(R₁₁)₂, —C(S)N(R₁₁)₂, tetrazole, triazole, amidine, guanidine, thioguanidine, cyanoguanidine, phenyl, naphthyl, and heteroaromatic, provided that any of the phenyl, naphthyl, or heteroaromatic is optionally substituted with up to 3 substituents independently selected from halogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, —OR₁₂, —SR₁₂, —CN, —NO₂, —N₃, —N(R₁₁)₂, —C(O)N(R₁₁)₂, and —C(S)N(R₁₁)₂;

[0108] Substituted heteroaromatic is the heteroaromatic ring having 1-3 substituents independently selected from halogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, —OR₁₁, —SR₁₁, —CN, —NO₂, —N₃, —N(R₁₁)₂, —C(O)N(R₁₁)₂, —C(S)N(R₁₁)₂, tetrazole, triazole, amidine, guanidine, thioguanidine, cyanoguanidine, phenyl, naphthyl, and heteroaromatic, provided that any of the phenyl, naphthyl, or heteroaromatic is optionally substituted with 1-3 substituents independently selected from halogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, —OR₁₂, —SR₁₂, —CN, —NO₂, —N₃, —N(R₁₁)₂, —C(O)N(R₁₁)₂, and —C(S)N(R₁₁)₂;

[0109] Alkyl is both straight- and branched-chain moieties having from 1-9 carbon atoms;

[0110] Substituted alkyl is the alkyl moiety having at least one substituent having 0-(2n+1) substituents independently selected from —F, —Cl, —Br, and —I, where n is the maximum number of carbon atoms in the moiety and further having 0-1 substituent selected from —CF₃, —OR₁₁, —SR₁₁, —N(R₁₁) 2, —C(O)R₁₁, —C(O)N(R₁₁) 2, —CN, —NR₁₁C(O)R₁₁, —S(O)₂N(R₁₁)₂, —NR₁₁S(O)₂R₁₁, —NO₂, phenyl, naphthyl, or heteroaromatic, provided that any of the phenyl, naphthyl, or heteroaromatic is optionally substituted with up to 3 substituents independently selected from halogen, alkyl, —CF₃, —OR₁₂, —SR₁₂, CN, NO₂, —N₃, —N(R₁₁)₂, —C(O)N(R₁₁)₂, and —C(S)N(R₁₁)₂;

[0111] Cycloalkyl is a cyclic alkyl moiety having from 3-8 carbon atoms;

[0112] Substituted cycloalkyl is the cycloalkyl moiety having at least one substituent having up to 4 substituents independently selected from —F, —Cl, —Br, and —I, and further having up to 1 substituent selected from —CF₃, —CN, —NO₂, —OR₁₁, —SR₁₁, —N(R₁₁)₂, —C(O)R₁₁, —C(O)N(R₁₁)₂, —NR₁₁C(O)R₁₁, —S(O)₂N(R₁₁)₂, —NR₁₁S(O)₂R₁₁, phenyl, naphthyl, and heteroaromatic, provided that any of the phenyl, naphthyl, or heteroaromatic is optionally substituted with 1-3 substituents independently selected from halogen, alkyl, —CF₃, —OR₁₂, —SR₁₂, CN, NO₂, —N₃, —N(R₁₁)₂, —C(O)N(R₁₁)₂, and —C(S)N(R₁₁)₂;

[0113] Heterocycloalkyl is a cyclic ring moiety having from 4-7 atoms with 1-2 atoms within the ring selected from N, O, and S;

[0114] Each R₁₁ is independently selected from H, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, phenyl, naphthyl, and heteroaromatic, provided that any of the alkyl, cycloalkyl, phenyl, naphthyl, or heteroaromatic is optionally substituted with up to 3 substituents independently selected from halogen, alkyl, —CF₃, —OR₁₂, —SR₁₂, —CN, —NO₂, —N₃, —N(R₁₂)₂, —C(O)N(R₁₂)₂, and —C(S)N(R₁₂)₂;

[0115] Each R₁₂ is independently selected from H, alkyl, and cycloalkyl, provided that any of the alkyl or cycloalkyl is optionally substituted with up to 2 substituents independently selected from halogen, —CF₃, —NO₂, —NH₂, —N₃, —CN, —OH, —O-lower alkyl, and —O-lower substituted alkyl;

[0116] Lower alkyl is both straight- and branched-chain moieties having from 1-4 carbon atoms;

[0117] Lower substituted alkyl is the lower alkyl moiety having at least one substituent optionally having up to (2n+1) substituents independently selected from —F, —Cl, —Br, and —I, where n is the maximum number of carbon atoms in the moiety and optionally further having up to 1 substituent independently selected from —CF₃, —NO₂, —NH₂, —CN, —OH, —O-lower alkyl, wherein the lower alkyl of —O-lower alkyl is optionally substituted with 1 substituent selected from —CF₃, —NO₂, —NH₂, —CN, —OH;

[0118] and pharmaceutically acceptable salts thereof.

[0119] The compounds of Formulas I, Ia and Ib are used to treat anxiety, depression, or other CNS diseases. The arylsulphonyl carbazoles (I, Ia and Ib) are administered orally, sublingually, transdermally or parenterally to provide a dosage of about 0.1 to about 50 mg/kg/day. It is preferred that the dosage range be from about 0.1 to about 10 mg/kg/day. The arylsulphonyl carbazoles (I) can be administered in divided doses either two, three or four times daily. For parenteral administration, a saline solution, dextrose solution, or water may be used as a suitable carrier. Formulations for parenteral administration may be in the form of aqueous or non-aqueous isotonic sterile injection solutions or suspensions. These solutions and suspensions may be prepared from sterile powders or granules having one or more of the carriers or diluents mentioned for use in the formulations for oral administration. The compounds may be dissolved in water, polyethylene glycol, propylene glycol, ethanol, corn oil, cottonseed oil, peanut oil, sesame oil, benzyl alcohol, sodium chloride, and/or various buffers. Other adjuvants and modes of administration are well and widely known in the pharmaceutical art. It is preferred that the arylsulphonyl carbazoles (I, Ia and Ib) be administered orally.

[0120] The exact dosage and frequency of administration depends on the particular arylsulfonyl carbazole(s) used, the particular disease being treated, the severity of the disease being treated, the age, weight, general physical condition of the particular patient, other medication the individual may be taking as is well known to those skilled in the art and can be more accurately determined by measuring the blood level or concentration of the arylsulphonyl carbazole (I, Ia and Ib) in the patient's blood and/or the patient's response to the particular condition being treated.

[0121] The arylsulphonyl carbazole (I, Ia and Ib) compounds of the present invention may be incorporated into pharmaceutical compositions for treating different CNS diseases, such as anxiety or depression. The pharmaceutical compositions may include one or more arylsulphonyl carbazole (I, Ia and Ib) compounds. The compositions also may contain well known carriers and excipients in addition to a therapeutically effective amount of compounds of Formulas I, Ia and Ib. The term “carrier” material or “excipient” herein means any substance, not itself a therapeutic agent, used as a carrier and/or diluent and/or adjuvant, or vehicle for delivery of a therapeutic agent to a subject or added to a pharmaceutical composition to improve its handling or storage properties or to permit or facilitate formation of a dose unit of the composition into a discrete article such as a capsule or tablet suitable for oral administration. Excipients can include, by way of illustration and not limitation, diluents, disintegrants, binding agents, adhesives, wetting agents, polymers, lubricants, glidants, substances added to mask or counteract a disagreeable taste or odor, flavors, dyes, fragrances, and substances added to improve appearance of the composition. Acceptable excipients include lactose, sucrose, starch powder, cellulose esters of alkanoic acids, cellulose alkyl esters, talc, stearic acid, magnesium stearate, magnesium oxide, sodium and calcium salts of phosphoric and sulfuric acids, gelatin, acacia gum, sodium alginate, polyvinyl-pyrrolidone, and/or polyvinyl alcohol, and then tableted or encapsulated for convenient administration. Such capsules or tablets may contain a controlled-release formulation as may be provided in a dispersion of active compound in hydroxypropyl-methyl cellulose, or other methods known to those skilled in the art. For oral administration, the pharmaceutical composition may be in the form of, for example, a tablet, capsule, suspension or liquid. If desired, other active ingredients may be included in the composition.

[0122] In addition to the oral dosing, noted above, the compositions of the present invention may be administered by any suitable route, in the form of a pharmaceutical composition adapted to such a route, and in a dose effective for the treatment intended. The compositions may, for example, be administered parenterally, e.g., intravascularly, intraperitoneally, subcutaneously, or intramuscularly. For parenteral administration, saline solution, dextrose solution, or water may be used as a suitable carrier. Formulations for parenteral administration may be in the form of aqueous or non-aqueous isotonic sterile injection solutions or suspensions. These solutions and suspensions may be prepared from sterile powders or granules having one or more of the carriers or diluents mentioned for use in the formulations for oral administration. The compounds may be dissolved in water, polyethylene glycol, propylene glycol, ethanol, corn oil, cottonseed oil, peanut oil, sesame oil, benzyl alcohol, sodium chloride, and/or various buffers. Other adjuvants and modes of administration are well and widely known in the pharmaceutical art.

DEFINITIONS

[0123] Alkyl is both straight- and branched-chain moieties having from 1-9 carbon atoms. For example, C_1-9 alkyl includes methyl, ethyl, propyl, isopropyl, butyl, iso-butyl, sec-butyl, pentyl, 3-pentyl, hexyl, and isomeric forms thereof.

[0124] Examples of heteroaromatic groups include, but are not limited to, thienyl, benzothienyl, pyridyl, thiazolyl, quinolyl, pyrazinyl, pyrimidyl, imidazolyl, furanyl, benzofuranyl, benzothiazolyl, isothiazolyl, benzisothiazolyl, benzisoxazolyl, benzimidazolyl, indolyl, benzoxazolyl, pyrazolyl, triazolyl, tetrazolyl, isoxazolyl, oxazolyl, pyrrolyl, isoquinolinyl, cinnolinyl, indazolyl, indolizinyl, phthalazinyl, pydridazinyl, triazinyl, isoindolyl, purinyl, oxadiazolyl, benzothiophenyl, benzothiazolyl, quinazolinyl, quinoxalinyl, naphthridinyl, and furopyridinyl.

[0125] Examples of heterocycloalkyl groups include, but are not limited to, tetrahydrofurano, tetrahydropyrano, morpholino, pyrrolidino, piperidino, piperazine, and 6

[0126] where m is 0, 1, or 2.

[0127] All temperatures are in degrees Centigrade.

[0128] HPLC refers to high pressure liquid chromatography.

[0129] DMSO refers to dimethylsulfoxide.

[0130] DMF refers to dimethylformamide.

[0131] Saline refers to an aqueous saturated sodium chloride solution.

[0132] Chromatography (column and flash chromatography) refers to purification/separation of compounds expressed as (support, eluent). It is understood that the appropriate fractions are pooled and concentrated to give the desired compound(s).

[0133] Generally, the following numbering system is used with the compounds of the present invention: 7

[0134] IR refers to infrared spectroscopy.

[0135] NMR refers to nuclear (proton) magnetic resonance spectroscopy, chemical shifts are reported in ppm (6) downfield from tetramethylsilane.

[0136] HRMS refers to high resolution mass spectrometry. FAB refers to fast atom bombardment.

[0137] Pharmaceutically acceptable refers to those properties and/or substances which are acceptable to the patient from a pharmacological/toxicological point of view and to the manufacturing pharmaceutical chemist from a physical/chemical point of view regarding composition, formulation, stability, patient acceptance and bioavailability.

[0138] When solvent pairs are used, the ratios of solvents used are volume/volume (v/v).

[0139] When the solubility of a solid in a solvent is used the ratio of the solid to the solvent is weight/volume (wt/v).

[0140] Compounds of the present invention may be in the form of pharmaceutically acceptable salts. The term “pharmaceutically acceptable salts” refers to salts prepared from pharmaceutically acceptable non-toxic bases including inorganic bases and organic bases, and salts prepared from inorganic acids, and organic acids. Salts derived from inorganic bases include aluminum, ammonium, calcium, ferric, ferrous, lithium, magnesium, potassium, sodium, zinc, and the like. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, such as arginine, betaine, caffeine, choline, N,N-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylamino-ethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, and the like. Salts derived from inorganic acids include salts of hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, phosphorous acid and the like. Salts derived from pharmaceutically acceptable organic non-toxic acids include salts of C_1-6 alkyl carboxylic acids, di-carboxylic acids, and tri-carboxylic acids such as acetic acid, propionic acid, fumaric acid, succinic acid, tartaric acid, maleic acid, adipic acid, and citric acid, and aryl and alkyl sulfonic acids such as toluene sulfonic acids and the like.

[0141] By the term “effective amount” of a compound as provided herein is meant a nontoxic but sufficient amount of the compound(s) to provide the desired effect. As pointed out below, the exact amount required will vary from subject to subject, depending on the species, age, and general condition of the subject, the severity of the disease that is being treated, the particular compound(s) used, the mode of administration, and the like. Thus, it is not possible to specify an exact “effective amount.” However, an appropriate effective amount may be determined by one of ordinary skill in the art using only routine experimentation.

Preparation of Arylsulphonyl Substituted Carbazoles

[0142] Compounds of Formulas I, Ia and Ib of the present invention may be prepared using the following reaction schemes:

[0143] Arylsulphonylphenylhydrazines can be prepared by the reactions outlined in Scheme 1. 8

[0144] The appropriately substituted thiols (1) are either known to those skilled in the art or can be readily prepared from known starting materials by means well known to those skilled in the art. Thiol (1) can be coupled with the appropriately substituted nitrobenzene, e.g., 4-chloro-1-nitrobenzene (2), by known means to produce the thioether (3). Only one arylsulphonyl group, e.g., R₅ in Formula I, and one R group, e.g., one of R₄, R₆, and R₇, are shown. For simplicity, the other R groups are not shown. Typically if R₄, R₆, and R₇ are substituents other than —H, those moieties should be part of the substituted nitrobenzene (2) so that they become incorporated into the unsubstituted arylsulfone (10) when it is formed. In general, adding phenyl substitutents (other than —H) to the unsubstituted arylsulfone (10) once it is formed is difficult. The substitution pattern at the C-5, C-6, C-7, and C-8 positions of the carbazoles of Formulas I, Ia and Ib can be produced by varying the substitution pattern on the substituted nitrobenzene.

[0145] Oxidizing the thioether (3) with oxone followed by hydrogenation with rhodium on carbon (5%), all of which is known to those skilled in the art, produce the amine (5). The amine (5) can be diazotized by (sodium) nitrite and (hydrochloric) acid followed by reduction with tin chloride to give the corresponding hydrazine (6).

[0146] Scheme 2 illustrates a schematic synthesis for preparing compound (9). Reaction of 4-aminocyclohexanol (7) with N-carbethoxyphthalimide produces the phthalimide compound (8), which when oxidized with an oxidant such as pyridinium chlorochromate (PCC) provides ketone (9). 9

[0147] Compounds of formula I can be prepared by the reactions outlined in Scheme 3 (where R₁═R₂═R₃═R₄═R₆═R₇═H) Fisher indole synthesis using hydrazine (6) and cyclohexanone (9) generates indole (10). The phthalimide group can be removed by reaction with hydrazine to produce the free amine (11). For convenience of resolution on a chiral column, the amino group can be protected to form the Boc protected compound (12), which, in turn, can be subjected to HPLC. After separation, individually treating the two enantiomers (13) and (14) with acid, such as hydrochloric acid, provides the hydrochloride salt of amines (15) and (16), respectively. 10

[0148] Compounds of Formulas I, Ia and Ib can also be prepared by the reactions outlined in Scheme 4. The R₃ group such as an alkyl can be introduced on the indole nitrogen by treating compound (10) with sodium hydride and electrophiles to produce compound (17). After deprotection with hydrazine, resolving the free amine (18) on a chiral column generates the two enantiomers (19) and (20), which can also be protected with a protecting group such as Boc. The R₁ group can be introduced by reacting 21 (or 22) with a base such as sodium hydride and quenched with an electrophile. After removing the protecting group (Boc) under acidic conditions, such as with hydrochloric acid, reductive amination with an aldehyde in the presence of a reducing agent such as sodium cyanoborohydride (see for example Lane, C. F., “Sodium Cyanoborohydride—A Highly Selective Reducing Agent for Organic Functional Groups”, Synthesis, 1975, 135) provides the tertiary amines 27 and 28, respectively. 11 12

[0149] Compounds of Formula Ia where ---[b] is a single bond which can be prepared by the reactions outlined in Scheme 5. The resolved amino compounds 19 (or 20) can be treated with a reducing reagent such as sodium cyanoborohydride in an acid media such as trifluoroacetic acid or acetic acid to lead to the formation of the indoline compounds 29 (or 30). 13

[0150] The invention also includes isotopically-labeled compounds, which are identical to those recited in Formulas I, Ia and Ib but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Examples of isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine, iodine, and chlorine, such as ³H, ¹¹C, ¹⁴C, ¹³N, ¹⁵O, ¹⁸F, ^99m Tc, ¹²³I, and ¹²⁵I. Compounds of the present invention and pharmaceutically acceptable salts and prodrugs of said compounds that contain the aforementioned isotopes and/or other isotopes of other atoms are within the scope of the invention. Isotopically-labeled compounds of the present invention are useful in drug and/or substrate tissue distribution and target occupancy assays. For example, isotopically labeled compounds are particularly useful in SPECT (single photon emission computed tomography) and in PET (positron emission tomography).

[0151] Single-photon emission computed tomography (SPECT), acquires information on the concentration of isotopically labeled compounds introduced to a mammal's body. SPECT dates from the early 1960's, when the idea of emission traverse section tomography was introduced by D. E. Kuhl and R. Q. Edwards prior to either PET, x-ray CT, or MRI. In general, SPECT requires isotopes that decay by electron capture and/or gamma emission. Example of viable SPECT isotopes include, but are not limited to, 123-iodine (¹²³I) and 99m-technetium (^99mTc). Subjects are injected with a radioactively labeled agent, typically at tracer doses. The nuclear decay resulting in the emission of a single gamma ray which passes through the tissue and is measured externally with a SPECT camera. The uptake of radioactivity reconstructed by computers as a tomogram shows tissue distribution in cross-sectional images.

[0152] Positron emission tomography (PET) is a technique for measuring the concentrations of positron-emitting isotopes within the tissues. Like SPECT, these measurements are, typically, made using PET cameras outside of the living subjects. PET can be broken down into several steps including, but not limited to, synthesizing a compound to include a positron-emitting isotope; administering the isotopically labeled compound to a mammal; and imaging the distribution of the positron activity as a function of time by emission tomography. PET is described, for example, by Alavi et al. in Positron Emission Tomography. published by Alan R. Liss, Inc. in 1985.

[0153] Positron-emitting isotopes used in PET include, but are not limited to, Carbon-11, Nitrogen-13, Oxygen-15, and Fluorine-18. In general, positron-emitting isotopes should have short half-lives to help minimize the long term radiation exposure that a patient receives from high dosages required during PET imaging.

[0154] In certain instances, PET imaging can be used to measure the binding kinetics of compounds of this invention with 5-HT₆ serotonin receptors. For example, administering an isotopically labeled compound of the invention that penetrates into the body and binds to a 5-HT₆ serotonin receptor creates a baseline PET signal which can be monitored while administering a second, different, non-isotopically labeled compound. The baseline PET signal will decrease as the non-isotopically labeled compound competes for the binding to the 5-HT₆ serotonin receptor.

[0155] In general, compounds of formula I that are useful in performing PET or SPECT are those which penetrate the blood-brain barrier, exhibit high selectivity and modest affinity to 5-HT₆ serotonin receptors, and are eventually metabolized. Compounds that are non-selective or those that exhibit excessive or small affinity for 5-HT₆ serotonin receptors are, generally, not useful in studying brain receptor binding kinetics with respect to 5-HT₆ serotonin receptors. Compounds that are not metabolized may harm the patient.

[0156] In other embodiments, nuclear magnetic resonance spectroscopy (MRS) imaging can be used to detect the overall concentration of a compound or fragment thereof containing nuclei with a specific spin. In general, the isotopes useful in NMR imaging include, but are not limited to, hydrogen-1, carbon-13, phosphorus-31, and fluorine-19.

[0157] Further, substitution with heavier isotopes such as deuterium, i.e., ²H, can afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements and, hence, maybe preferred in some circumstances. Isotopically labeled compounds of Formula I of this invention can generally be prepared by carrying out the synthetic procedures described above by substituting an isotopically labeled reagent for a non-isotopically labeled reagent.

EXAMPLES

[0158] Without further elaboration, it is believed that one skilled in the art can, using the preceding description, practice the present invention to its fullest extent. The following detailed examples describe how to prepare the various compounds and/or perform the various processes of the invention and are to be construed as merely illustrative, and not limitations of the preceding disclosure in any way whatsoever. Those skilled in the art will promptly recognize appropriate variations from the procedures both as to reactants and as to reaction conditions and techniques.

[0159] Preparation 1: 2-(4-Oxocyclohexyl)-1H-isoindole-1,3(2H)-dione: 14

[0160] Step 1: A solution of 4-aminocyclohexanol hydrochloride (2.52 g, 16.6 mmol) in water (20.0 mL) was treated with N-carbethoxyphthalimide (3.82 g, 17.4 mmol) and Na₂CO₃ (3.77 g, 35.6 mmol). The reaction was stirred at room temperature for 15.6 hours. The reaction was cooled to 0° C. and quenched with 10% HCl, filtered, and washed with water to give a white solid. The solid was dissolved in ethyl acetate washed with water, brine, dried over MgSO₄ and concentrated in vacuo to give 3.10 g (76%) of 2-(4-hydroxycyclohexyl)-1H-isoindole-1,3(2H)-dione as a colorless solid: mp 176.9-177.0° C.; ¹H NMR (400 MHz, Acetone-d₆) δ 7.82 4.09, 3.74, 3.62, 2.28, 2.04, 1.76, 1.39; ¹³C NMR (100 MHz, acetone-d₆) δ 168.7, 135.1, 133.0, 123.6, 69.5, 50.8, 35.7, 28.3; IR (mull) 3389, 3318, 2953, 2930, 2876, 2861, 1767, 1703, 1463, 1393, 1377, 1088, 1075, 1061, 720 cm⁻¹; HRMS (FAB) calcd for C₁₄H₁₆NO₃: 246.1130, found 246.1128; Anal. Calcd for C₁₄H₁₅NO₃: C, 68.56; H, 6.16; N, 5.71. Found: C, 68.39; H, 6.21; N, 5.70.

[0161] Step 2: A solution of 2-(4-hydroxycyclohexyl)-1H-isoindole-1,3(2H)-dione (3.10 g, 12.6 mmol) in CH₂Cl₂ (25.0 mL) was added to a slurry of PCC (4.10 g, 19.0 mmol) in CH₂Cl₂ (15.0 mL) and stirred at room temperature for 3.5 hours. The reaction was diluted with Et₂O (60.0 mL), decanted and the residue swirled with Et₂O (2×40.0 mL). The combined ether layers were filtered through florisil and concentrated in vacuo to dryness, and the residue was recrystallized from ethyl acetate/hexane to give 2.01 g (65%) of 2-(4-oxocyclohexyl)-1H-isoindole-1,3(2H)-dione as colorless needles: mp 140.3-142.1° C.; ¹H NMR (400 MHz, CDCl₃) δ 7.84, 7.74, 4.64, 2.72, 2.54, 2.09; ¹³C NMR (100 MHz, CDCl₃) δ 208.9, 168.1, 134.1, 131.9, 123.3, 48.4, 39.9, 28.6; IR (mull) 3062, 3031, 2958, 2949, 2919, 2885, 1775, 1762, 1721, 1708, 1611, 1465, 1436, 1419, 1393, 1379, 719 cm⁻¹; HRMS (FAB) calcd for C₁₄H₁₄NO₃: 244.0974, found 244.0976; Anal. Calcd for C₁₄H₁₄NO₃: C, 69.12; H, 5.39; N, 5.76. Found: C, 68.87; H, 5.47; N, 5.73.

Example 1

[0162] 6-(Phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-amine hydrochloride (racemic): 15

[0163] Step 1: A solution of 2-(4-oxocyclohexyl)-1H-isoindole-1,3[2H]-dione (3.99 g, 16.4 mmol) and 1-[4-(phenylsulfonyl)phenyl]hydrazine (3.69 g, 14.9 mmol) in formic acid (45.0 mL) was heated to reflux for 15.4 hours then cooled to room temperature, diluted with ethyl acetate, filtered and concentrated in vacuo to give 2.678 g (39%) of (rac)-2-[6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-yl]-1H-isoindole-1,3[2H]-dione as colorless solid. The filtrate was concentrated in vacuo and subjected to column chromatography (EtOAc/hexane, 1:1 and 1% triethylamine) to give an additional 0.57 g (8%) of the title compound: mp>275° C.; ¹H NMR (400 MHz, DMSO-d₆) δ 11.50, 8.00, 7.90, 7.55, 7.47, 4.49, 3.31, 2.95, 2.68, 2.12; ¹³C NMR (100 MHz, DMSO-d₆) δ 167.8, 142.8, 138.3, 136.9, 134.4, 132.7, 131.4, 130.4, 129.3, 126.7, 126.4, 122.9, 119.3, 117.8, 111.5, 108.3, 47.3, 26.0, 24.1, 22.3; IR (drift) 2482, 1989, 1710, 1392, 1374, 1342, 1305, 1154, 1109, 1092, 760, 739, 716, 684, 629 cm⁻¹; HRMS (FAB) calcd for C₂₆H₂₀N₂O₄S+H 457.1222, found 457.1239; Anal. Calcd for C₂₆H₂₀N₂O₄S: C, 68.40; H, 4.42; N, 6.14; S, 7.02. Found: C, 68.38; H, 4.47; N, 6.13.

[0164] Step 2: To a solution of (rac)-2-[6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-yl]-1H-isoindole-1,3[2H]-dione (3.23 g, 7.1 mmol) in methanol (70.0 mL) was added hydrazine hydrate (6.6 mL, 136 mmol). After stirring at room temperature for 2.3 hours the reaction was concentrated in vacuo to dryness. The residue was stirred with CH₂Cl₂ for 0.7 hours. The undissolved solid was removed by filtration, and the filtrate was washed with water, brine, and concentrated in vacuo to give 1.59 g (69%) of colorless solid. The colorless solid (0.26 g, 0.80 mmol) was treated with a 4.0 N HCl in dioxane (10.0 mL) and stirred at room temperature for 6.5 hours. After the reaction mixture was concentrated in vacuo, methanol was added, and the solution was concentrated in vacuo and recrystallized from CH₃OH/ethyl acetate to give 0.063 g (22%) of 6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-amine hydrochloride (racemic) as a light yellow solid: mp 205-211° C.; ¹H NMR (400 MHz, DMSO-d₆) δ 11.60, 8.40, 8.03, 7.93, 7.57, 7.47, 3.53, 3.13, 2.86, 2.79, 2.20, 1.97; ¹³C NMR (100 MHz, DMSO-d₆) δ 142.8, 138.2, 136.6, 132.8, 130.5, 129.4, 126.7, 126.2, 119.4, 117.7, 111.6, 106.4, 46.5, 26.3, 25.2, 20.3; IR (drift) 3445, 3404, 3228, 3146, 2947, 2932, 2906, 2842, 1298, 1153, 1143, 1130, 1093, 732, 688 cm⁻¹; HRMS (FAB) calcd for C₁₈H₁₈N₂O₂S+H: 327.1167, found 327.1166; Anal. Calcd for C₁₈H₁₈N₂O₂S.HCl.1.2H₂O: C, 56.23; H, 5.61; N, 7.29. Found: C, 56.32; H, 5.71; N, 7.39.

Example 2

[0165] (3S)-6-(Phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-amine hydrochloride and (3R)-6-(Phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-amine hydrochloride: 16

[0166] Step 1: Di-tert-butyl dicarbonate (1.09 g, 4.98 mmol) was added to a solution of (rac)-6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-amine (1.29 mg, 3.96 mmol) in CH₂Cl₂ (30.0 mL). The reaction was stirred at room temperature for 2.2 hours then washed with water, saturated NaHCO₃, brine, dried over MgSO₄ and concentrated in vacuo to a brown oil. The oil was subjected to column chromatography (50% ethyl acetate/hexane) to give 1.39 g (82%) of (rac) tert-butyl 6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-ylcarbamate as a colorless solid. The racemic mixture was separated into the two enantiomers on HPLC by using a chiral column: 0.46×25 cm chiralpak AD, eluted with 20% isopropanol/hexane at 0.5 mL/min, detector set at 280 nM.

[0167] Fraction 1 (the first-eluting fraction, 0.62 g, 37%): mp 133.8-137.8° C. ¹H NMR (400 MHz, CDCl₃) δ 8.39, 8.06, 7.93, 7.62, 7.46, 7.32, 4.72, 4.05, 3.06, 2.80, 2.58, 2.09, 1.92, 1.47; ¹³C NMR (100 MHz, CDCl₃) δ 155.5, 143.0, 138.4, 135.8, 132.5, 131.6, 129.1, 127.4, 127.2, 120.5, 118.8, 111.2, 109.3, 79.5, 46.3, 28.5, 28.47, 27.9, 20.9; IR (drift) 3275, 1678, 1510, 1478, 1368, 1337, 1314, 1291, 1263, 1157, 1133, 1091, 727, 687, 640 cm⁻¹; Anal. Calcd for C₂₃H₂₆N₂O₄S: C, 64.77; H, 6.14; N, 6.57. Found: C, 64.53; H, 6.24; N, 6.57.

[0168] Fraction 2 (0.55 g, 33%): mp 135.7-139.4° C.; ¹H NMR (400 MHz, CDCl₃) δ 8.39, 8.06, 7.92, 7.62, 7.45, 7.32, 4.72, 4.05, 3.06, 2.80, 2.56, 2.09, 1.92, 1.47; ¹³C NMR (100 MHz, CDCl₃) δ 155.5, 143.0, 138.4, 135.8, 132.5, 131.6, 129.1, 127.4, 127.2, 120.5, 118.8, 111.1, 109.3, 79.5, 46.3, 28.5, 28.4, 27.9, 20.9; IR (drift) 3275, 1678, 1510, 1478, 1368, 1314, 1291, 1263, 1245, 1156, 1133, 1091, 727, 687, 640 cm⁻¹; Anal. Calcd for C₂₃H₂₆N₂O₄S: C, 64.77; H, 6.14; N, 6.57. Found: C, 64.56; H, 6.23; N, 6.55.

[0169] The stereochemistry of Fractions 1 and 2 were not identified.

[0170] Step 2: Fraction 1 from Step 1 above (0.59 g, 1.38 mmol) was dissolved in 4.0 N HCl in dioxane (5.0 mL) and stirred at room temperature for 15.6 hours. After the reaction mixture was concentrated in vacuo, methanol was added and the solution was concentrated in vacuo and recrystallized from CH₃OH/ethyl acetate to give 0.39 g (78%) of one isomer of Example 2 as a colorless solid: mp 216-218° C.; ¹H NMR (400 MHz, DMSO-d₆) δ 11.60, 8.37, 8.03, 7.92, 7.57, 7.47, 3.57, 3.13, 2.86, 2.78, 2.20, 1.96; ¹³C NMR (100 MHz, DMSO-d₆) δ 142.8, 138.2, 136.6, 132.8, 130.5, 129.4, 126.7, 126.2, 119.4, 117.7, 111.6, 106.4, 46.5, 26.3, 25.2, 20.3; IR (drift) 3334, 3218, 3158, 3054, 3002, 2924, 2903, 2850, 1476, 1299, 1151, 1131, 1092, 731, 613 cm⁻¹; HRMS (FAB) calcd for C₁₈H₁₈N₂O₂S+H: 327.1167, found 327.1167; Anal. Calcd for C₁₈H₁₈N₂O₂S.HCl.0.5EtOAc.0.75H₂O: C, 57.14; H, 5.87; N, 6.66. Found: C, 57.19; H, 6.00; N, 6.73.

[0171] Following the general procedure of Step 2, starting with Fraction 2 from Step 1 above, making non-critical variations, the other isomer of Example 2 was obtained as a colorless solid (79%): mp 224-227° C.; ¹H NMR (400 MHz, DMSO-d₆) δ 11.60, 8.37, 8.04, 7.92, 7.57, 7.47, 3.57, 3.13, 2.86, 2.79, 2.20, 1.96; ¹³C NMR (100 MHz, DMSO-d₆) δ 142.8, 138.2, 136.6, 132.8, 130.5, 129.4, 126.7, 126.2, 119.4, 117.7, 111.6, 106.4, 46.5, 26.3, 25.2, 20.3; IR (drift) 3218, 3156, 3053, 3003, 2924, 2907, 2853, 1477, 1299, 1152, 1131, 1093, 731, 688, 613 cm⁻¹; HRMS (FAB) calcd for C₁₈H₁₈N₂O₂S+H: 327.1167, found 327.1175; Anal. Calcd for C₁₈H₁₈N₂O₂S.HCl.0.35 EtOAc.0.35H₂O.0.40CH₃OH: C, 57.61; H, 5.88; N, 6.79. Found: C, 57.59; H, 6.06; N, 6.78.

Example 3(a)

[0172] (3R)-9-Methyl-6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-amine: 17

Example 3(b)

[0173] (3S)-9-Methyl-6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-amine: 18

[0174] Step 1: A solution of (rac)-2-[6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-yl]-1H-isoindole-1,3[2H]-dione (2.93 g, 6.4 mmol) in DMF (10.0 mL) was added to a 0° C. suspension of 60% sodium hydride (0.51 g, 12.7 mmol) in DMF (3.0 mL) and stirred for 0.4 hours. Methyl iodide (1.50 g, 10.6 mmol) was added, and the reaction was stirred at room temperature for 3.67 hours. The reaction was quenched with water and extracted with CH₂Cl₂. The CH₂Cl₂ extracts were washed with water, brine, and the dried over MgSO₄ and concentrated in vacuo to give 1.74 g (58%) of (rac)-2-[9-methyl-6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-yl]-1H-isoindole-1,3[2H]-dione as a colorless solid: ¹H NMR (400 MHz, DMSO-d₆) δ 8.06, 7.97-7.88, 7.66-7.55, 4.49, 3.70, 3.38-3.33, 3.05-3.01, 2.88-2.86, 2.75-2.70, 2.21; ¹³C NMR (100 MHz, DMSO-d₆) δ 168.1, 143.2, 139.1, 138.5, 134.6, 132.9, 131.8, 130.9, 129.5, 127.0, 126.0, 123.1, 119.4, 118.2, 110.3, 108.4, 47.4, 26.2, 24.3, 21.5; IR (drift) 1710 (s), 1391, 1373, 1303, 1151, 1113, 1089, 814, 743, 719, 692, 644, 638, 618, 611 cm⁻¹; HRMS (FAB) calcd for C₂₇H₂₂N₂O₄S+H: 471.1378, found: 471.1383; Anal. Calcd for C₂₇H₂₂N₂O₄S: C, 68.92; H, 4.71; N, 5.95. Found: C, 68.50; H, 4.82; N, 5.88.

[0175] Step 2: To a solution of (rac) 2-[9-methyl-6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-yl]-1H-isoindole-1,3[2H]-dione (1.70 g, 3.6 mmol) in methanol (100 mL) was added hydrazine hydrate (1.6 mL, 33 mmol). After stirring at room temperature for 4.75 hours, the reaction was concentrated in vacuo. The residue was dissolved in CH₂Cl₂ and concentrated in vacuo to give 0.77 g (63%) of (rac) 9-methyl-6-(phenylsulfonyl)-2,3,4,9-tertrahydro-1H-carbazol-3-amine as a yellow oil, which was separated into enantiomers on HPLC by using a chiral column: 0.46×25 cm chiralpack AD, eluted with 0.05% diethylamine/ethanol at 0.5 mL/min, dector set at 280 nM.

[0176] Example 3(a): Fraction 1: (First-eluting fraction, 86 mg, 7%); mp 189.3-193.2° C.; [α]_D=+29° (C 1.04, DMSO) ¹H NMR (400 MHz, DMSO-d₆) δ 8.04, 7.94-7.92, 7.63-7.54, 3.64, 3.39-3.06, 2.91-2.79, 2.66-2.60, 2.14, 1.88; ¹³C NMR (100 MHz, DMSO-d₆) δ 142.7, 138.6, 138.1, 132.8, 130.5, 129.4, 126.7, 125.7, 119.2, 117.7, 110.1, 107.1, 46.5, 29.3, 27.9, 26.8, 19.4; IR (drift) 3225, 3217, 3156, 3054, 2998, 2931, 1611, 1482, 1377, 1312, 1304, 1151, 1091, 729, 624 cm⁻¹; HRMS (FAB) calcd for C₁₉H₂₀N₂O₂S+H: 341.1324, found: 341.1323; Anal. Calcd for C₁₉H₂₀N₂O₂S.2H₂O: C, 60.62; H, 6.43; N, 7.44. Found: C, 60.36; H, 5.95; N, 7.51.

[0177] Example 3(b): Fraction 2: (114 mg, 9%); [α]_D=−30° (C 1.02, DMSO) ¹H NMR (400 MHz, DMSO-d₆) δ 8.04, 7.94-7.92, 7.63-7.54, 3.64, 3.39-3.06, 2.91-2.79, 2.66-2.60, 2.14, 1.88; ¹³C NMR (100 MHz, DMSO-d₆) δ 142.7, 138.6, 138.1, 132.8, 130.5, 129.4, 126.7, 125.7, 119.2, 117.8, 110.1, 106.9, 46.5, 29.3, 27.6, 26.5, 19.4; IR (drift) 3055, 3015, 2999, 2931, 2849, 1613, 1481, 1377, 1304, 1150, 1092, 730, 690, 624, 609 cm⁻¹; HRMS (FAB) calcd for C₁₉H₂₀N₂O₂S+H: 341.1324, found: 341.1335; Anal. Calcd for C₁₉H₂₀N₂O₂S.2H₂O: C, 60.62; H, 6.43; N, 7.44. Found: C, 60.06; H, 5.94; N, 7.51.

[0178] The identification of Example 3(b) was based on the x-ray crystallography of its (S)-mandelic acid derivative:

[0179] (2′S)-2′-hydroxy-N-[(3S)-9-methyl-6-(phenylsulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-3-yl]-2-phenylethanamide: 19

[0180] To a solution of (3S)-9-methyl-6-(phenylsulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-3-amine (0.500 g, 1.47 mmol), (S)-Mandelic acid (0.224 g, 1.47 mmol), 1-hydorxytriazole (0.199 g, 1.47 mmol) and triethylamine (0.21 mL, 0.147 mmol) in dichloromethane (15.0 mL) was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.282 g, 1.47 mmol) at 0° C. The resulted mixture was stirred at room temperature for over night. Water (20.0 mL) and dichloromethane (15.0 mL) were added and separated. The aqueous layer was extracted with dichloromethane (2×20.0 mL). The combined organic solutions was dried (MgSO₄) and filtered. The filtrated was concentrated in vacuo to dryness and the residue was subjected to column chromatography (EtOAc) to give 0.544 g (78%) of colorless solid as the title compound: mp 138-140° C. (EtOAc/hex); [α]_D=+78° (c 0.78, CHCl₃); ¹H NMR (400 MHz, CDCl₃) δ 8.02 (d, J=1.7 Hz, 1H), 7.93-7.90 (m, 2H), 7.68-7.66 (dd, J=8.6, 1.7 Hz, 1H), 7.48-7.31 (m, 10H), 7.25 (d, J=8.6 Hz, 1H), 6.49 (d, J=8.0 Hz, 1H), 5.05 (s, 1H), 4.28 (br, 1H), 3.57 (s, 3H), 3.02 (dd, J=15.3, 5.1 Hz, 1H), 2.72 (t, J=6.1 Hz, 2H), 2.52 (dd, J=15.3, 7.6 Hz, 1H), 2.08 (m, 1H), 1.94 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 171.9, 143.1, 139.5, 139.2, 137.2, 132.5, 131.2, 129.1, 128.8, 128.6, 127.2, 126.7, 126.6, 120.1, 118.8, 109.2, 108.2, 74.2, 45.2, 29.5, 28.0, 27.4, 19.9; IR (diffuse reflectance) 3406, 3396, 3268, 1663, 1644, 1638, 1619, 1525, 1522, 1449, 1304, 1288, 1151, 1088, 1061 cm⁻¹; HRMS (FAB) calcd for C₂₇H₂₆N₂O₄S+H 475.1691, found 475.1703; Anal. Calcd for C₂₇H₂₆N₂O₄S.0.25H₂O: C, 67.69; H, 5.57; N, 5.85. Found: C, 67.70; H, 5.64; N, 5.82.

Example 4

[0181] (3R)-N,9-Dimethyl-6-(phenylsulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-3-amine hydrochloride: 20

[0182] Step 1: Following the general procedure of EXAMPLE 2(a) (step 1) and making non-critical variations, tert-butyl (3R)-9-methyl-6-(phenylsulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-3-ylcarbamate was prepared as a brown solid (74%): mp 155-160° C.; [α]_D=−340 (c 1.01, chloroform); ¹H NMR (400 MHz, CDCl₃) δ 8.11, 7.95-7.92, 7.68, 7.50-7.42, 7.30, 4.65, 4.08, 3.63, 3.09, 2.82-2.79, 2.64, 2.13, 2.02-1.96, 1.46; ¹³C NMR (100 MHz, CDCl₃) δ 155.4, 143.2, 139.2, 137.3, 132.4, 131.3, 129.0, 127.2, 126.8, 120.2, 118.9, 109.2, 108.5, 79.5, 46.0, 29.5, 28.5, 28.4, 28.0, 19.8; IR (diffuse reflectance) 1701, 1519, 1482, 1367, 1300, 1289, 1181, 1173, 1163, 1151, 731, 687, 626, 613, 607 cm⁻¹; HRMS (FAB) calcd for C₂₄H₂₈N₂O₄S+H 441.1848, found 441.1873; Anal. Calcd for C₂₄H₂₈N₂O₄S: C, 65.43; H, 6.41; N, 6.36. Found: C, 65.35; H, 6.38; N, 6.38.

[0183] Step 2: A solution of tert-butyl (3R)-9-methyl-6-(phenylsulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-3-ylcarbamate (1.74 g, 3.95 mmol) in DMF (13.0 mL) was added to a 0° C. suspension of 60% sodium hydride (0.38 g, 9.62 mmol) in DMF (3.0 mL) and stirred at room temperature for 1.1 hours. Methyl iodide (0.30 mL, 4.81 mmol) was added, and the reaction was stirred at room temperature for 2.0 hours. The reaction was cooled to 0° C., quenched with water and filtered. The filtrate was concentrated in vacuo, combined with the previously filtered solid and partitioned between ethyl acetate and water. The organic layer was washed with brine, dried over MgSO₄ and concentrated in vacuo to dryness, the residue was recrystallized from EtOAc/hexane to give 1.36 g (76%) of tert-butyl methyl[(3R)-9-methyl-6-(phenylsulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-3-yl]carbamate as a colorless solid: mp 181.4-183.2° C.; [α]_D =+1030 (c 1.02, DMSO); ¹H NMR (400 MHz, DMSO-d₆) δ 8.06, 7.93-7.91, 7.62-7.53, 4.22, 3.64, 2.96-2.92, 2.84-2.79, 1.99-1.94, 1.42; ¹³C NMR (100 MHz, DMSO-d₆) δ 155.6, 142.8, 138.7, 138.0, 132.7, 130.5, 129.3, 126.7, 125.9, 119.1, 118.0, 110.0, 108.6, 78.5, 29.3, 28.5, 28.0, 26.4, 23.5, 21.2; IR (diffuse reflectance) 1684, 1481, 1448, 1398, 1378, 1364, 1357, 1304, 1184, 1149 (s), 1103, 732, 690, 622, 612 cm⁻¹; HRMS (FAB) calcd for C₂₅H₃₀N₂O₄S+H 455.2004, found 455.2027; Anal. Calcd for C₂₅H₃₀N₂O₄S: C, 66.05; H, 6.65; N, 6.16. Found: C, 65.99; H, 6.66; N, 6.19.

[0184] Step 3: Following the general procedure of EXAMPLE 2 (step 2) and making non-critical variations, (3R)-N,9-dimethyl-6-(phenylsulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-3-amine hydrochloride was prepared as a colorless solid (47%): mp>275° C.; ¹H NMR (400 MHz, DMSO-d₆) δ 9.25, 8.11, 7.91, 7.62-7.57, 3.65, 3.42, 3.28, 2.93, 2.81, 2.66, 2.35, 1.99; ¹³C NMR (100 MHz, DMSO-d₆) δ 142.7, 138.7, 138.0, 132.8, 130.6, 129.4, 126.7, 125.6, 119.4, 117.9, 110.2, 106.2, 54.0, 29.8, 29.4, 24.8, 23.1, 19.4; IR (diffuse reflectance) 2959, 2938, 2931, 2792, 2768, 2748, 2708, 2459, 1478, 1306, 1300, 1151, 1099, 732, 624 cm⁻¹; HRMS (FAB) calcd for C₂₀H₂₂N₂O₂S+H 355.1480, found 355.1485; Anal. Calcd for C₂₀H₂₂N₂O₂S: C, 61.45; H, 5.93; N, 7.17. Found: C, 61.16; H, 5.93; N, 7.12.

Example 5

[0185] (3R)-9-Methyl-6-(phenylsulfonyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazol-3-amine: 21

[0186] Step 1: A freshly prepared solution of sodium cyanoborohydride (0.91 g, 14.48 mmol) in CH₃OH (3.0 mL) was added dropwise to a 0° C. solution of (3R)-9-methyl-6-(phenylsulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-3-amine (1.02 g, 2.99 mmol) in TFA (7.5 mL), then stirred at room temperature for 3 hours. The reaction was diluted with H₂O (40 mL) cooled to 0° C. and made basic by the addition of 50% NaOH. The reaction mixture was extracted with EtOAc, washed with brine, dried over MgSO₄ and concentrated in vacuo to give a colorless foam which was recrystallized from CH₃OH/EtOAc to give 0.19 g (19%) of (3R)-9-methyl-6-(phenylsulfonyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazol-3-amine as a colorless as a mixture of cis and trans isomers: mp 217.0-219.3° C.; MS m/z 343.2 (M⁺+H).

5-HT₆ Receport Binding Assay

[0187] Growth of Cells and Membrane Preparation

[0188] Hela cells containing the cloned human 5-HT₆ receptor were acquired from Dr. David R. Sibley's laboratory in National Institute of Health (see Sibley, D. R., J. Neurochemistry, 66, 47-56, 1996). Cells were grown in high glucose Dulbecco's modified Eagle's medium, supplemented with L-glutamine, 0.5% sodium pyruvate, 0.3% penicillin-streptomycin, 0.025% G-418 and 5% Gibco fetal bovine serum and then were harvested, when confluent, in cold phosphate buffered saline.

[0189] Harvested intact cells were washed once in cold phosphate-buffered saline. The cells were pelleted and resuspended in 100 ml of cold 50 mM Tris, 5 mM EDTA and 5 mM EGTA, pH 7.4. Homogenization was with a Vir Tishear generator, 4 cycles for 30 seconds each at setting 50. The homogenized cells were centrifuged at 700 RPM (1000×g) for 10 minutes and the supernatant was removed. The pellet was resuspended in 100 ml of the above buffer and rehomogenized for 2 cycles. The rehomogenized cells were then centrifuged at 700 RPM (1000×g) for 10 minutes and the supernatant was removed. The combined supernatant (200 ml) was centrifuged at 23,000 RPM (80,000×g) for 1 hour in a Beckman Rotor (42.1 Ti). The membrane pellet was resuspended in 50-8- ml of assay buffer containing HEPES 20 mM, MgCl2 10 mM, NaCl 150 mM, EDTA 1 mM, pH 7.4 and stored frozen in aliqouts at −70° C.

[0190] 5-HT₆ Receptor Binding Assay

[0191] The radioligand binding assay used [³H]-lysergic acid diethylamide (LSD). The assay was carried out in Wallac 96-well sample plates by the addition of 11 μl of the test sample at the appropriate dilution (the assay employed 11 serial concentrations of samples run in duplicate), 11 μl of radioligand, and 178 μl of a washed mixture of WGA-coated SPA beads and membranes in binding buffer. The plates were shaken for about 5 minutes and then incubated at room temperature for 1 hour. The plates were then loaded into counting cassettes and counted in a Wallac MicroBeta Trilux scintillation counter.

[0192] Binding Constant (Ki) Determination

[0193] Eleven serial dilutions of test compounds were distributed to assay plates using the PE/Cetus Pro/Pette pipetter. These dilutions were, followed by radioligand and the bead-membrane mixture prepared as described above. The specifically bound cpm obtained were fit to a one-site binding model using GraphPad Prism ver. 3.0. Estimated IC₅₀ values were converted to Ki values using the Cheng-Prusoff equation (Cheng, Y. C. et al., Biochem. Pharmacol., 22, 3099-108, 1973). The Examples have Ki values from about 2.9 nM to about 58 nM.