Abstract:
The invention is directed to the use of a compound of formula I as defined herein, a pharmaceutically acceptable salt thereof; or a pharmaceutical composition containing a compound of formula I, in treating a mammal, including a human, for a psychiatric disorder or condition selected from the group consisting of depression, mood disorders, anxiety, schizophrenia, bipolar disorder (also referred to as manic-depressive disorder), addiction, cognitive impairment, Parkinson&#39;s and Alzheimer&#39;s diseases.

Description:
This U.S. patent application claims the benefit of U.S. Provisional Application No. 61/758,538 filed Jan. 30, 2013 and U.S. Non-Provisional Application Ser. No. 14/167,362 filed on Jan. 29, 2014. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention is directed to compounds of the formula I as described herein, to a pharmaceutical composition comprising such compounds and to methods of treating disorders or conditions that may be treated by administration of such compounds to a mammal in need, including humans. In particular, the compounds of the current invention are potentially useful for treating, e.g., depression, mood disorders, anxiety, schizophrenia, bipolar disorder (also referred to as manic-depressive disorder), addiction, obsessive-compulsive disorder, cognitive impairment, Parkinson&#39;s and Alzheimer&#39;s diseases. 
     Depression is a disease that afflicts a large segment of the U.S. population, estimated to be more than 20 million patients (Kessler, R. C., et al,  Archives of General Psychiatry,  2005, 62 (6):617-27). Symptoms of depression include alteration in mood (e.g., sadness, apathy), negative self-concept (e.g., self-reproach), vegetative changes (e.g., insomnia, anorexia, loss of libido), and changes in activity level (e.g., agitation, listlessness); it may be uni-polar or bi-polar (i.e., manic-depression). Traditionally, treatment of depressed individuals has included the use of psychotherapy, natural and/or synthetic pharmacological agents, or a combination of the two. Natural agents have included substances such as St. John&#39;s Wort. 
     Since the 1950&#39;s, pharmacological substances have played a dominant role in the treatment and recovery of patients. Following the recognition of the role of the neurotransmitters (NT) such as serotonin (5-hydroxytryptamine, 5-HT) in the Central Nervous System (CNS), more effective drugs have been designed and marketed to regulate this mood disorder. The drugs that are currently available—and most often prescribed—for the treatment of depression include serotonin selective reuptake inhibitors (SSRI&#39;s, e.g., fluoxetine, sertraline), serotonin-norepinephrine reuptake inhibitors (SNRI&#39;s, e.g., venlafaxine, duloxetine), tricyclic antidepressants (TCA&#39;s, e.g., desipramine, nortriptyline, amitriptyline) and other NTs in the CNS. While many of these therapeutic agents provide benefit to the patients who take them as prescribed, it may take several weeks or longer to achieve significant clinical relief from their most serious symptoms, e.g., a major concern for physicians dealing with depressed patients is the increased risk of suicide. Furthermore, it is estimated that approximately 30% or more of diagnosed patients do not achieve adequate clinical relief even after treatment with three or more different antidepressant medications. Coupled with potential side effects (e.g., gastrointestinal disturbances, sexual dysfunction and reduced libido) as well as development of potentially life-threatening serotonin syndrome, physicians and their patients are eagerly awaiting discovery of safer and more broadly efficacious treatments. 
     There continues to be great interest in identifying novel mechanisms of action for the treatment of depression and related mood disorders. Recently, interest has been drawn to the use of selective opioid agonists and antagonists, specifically those that interact with the kappa (κ) subtype, as a means of achieving faster onset of action with potentially better toleration (Carlezon, W. A., et al,  Pharmacology  &amp;  Therapeutics,  2009), (Zhang, H., et al,  European Journal of Pharmacology,  2007, 570:89-96), (Todtenkopf, M. S., et al,  Psychopharmacology  ( Berl. ) 2004, Jan. 16), (Ibegbu, A. O., et al,  British Journal of Pharmacology and Toxicology,  2011, 2(2):84-91) and (Gharagozlou, P., et al,  BioMed Central Pharmacology  ( Open Access ), 2006, January 25). Mague, et al ( Journal of Pharmacology and Experimental Therapeutics,  2003, 305:323-330) have published results of activity in a rat forced—swim test that demonstrate the potential for antidepressant activity of kappa opioid receptor (KOR) antagonists. 
     A review of the role of opioid receptors in the development of mood disorders is also available (Lutz, P. -E. and Kieffer, B. L.,  Trends in Neurosciences,  2013, 36(3):195-206). A. T. Knoll and W. A. Carlezon ( Brain Research,  2010, 1314:56-73) have also reported the results of their studies of the roles of dynorphin and KOR with respect to the role of stress in depression. 
     M. Bartolato, et al ( Biological Psychiatry,  2005, 57:1550-1558) have claimed positive results from studies of KOR agonists in a rat model of schizophrenia—disruption of prepulse inhibition—which suggest a possible therapeutic benefit for compounds having this activity. S. Yoshikawa, et al ( European Journal of Pharmacology,  2009, 606:102-108) have also described their findings with the KOR agonist TRK-820 in rat models of schizophrenia and suggest a therapeutic potential for this compound in the treatment of psychotic behavior. 
     Kappa receptors have also been implicated in addictive behavior and antagonists have shown potential utility in a mouse model of nicotine addiction and withdrawal (Jackson, K. J., et al,  Psychopharmacology, DOI  10.1007/s00213-010-1803-1). 
     B. Hahn, et al, ( Neuropharmacology,  2000, 39:2848-2855) have studied modulation of nicotine-induced behavior with Kappa agonists in rats. J. L Kissler, et al ( Biological Psychiatry,  2013) have studied the potential utility of KOR substances in alcohol self-administration, whereas the value of KOR selective compounds for the treatment of opioid and stimulant addiction was reviewed by S. D. Glick, et al ( Brain Research,  1995, 681:147-152) and E. R. Butelman, et al ( Trends in Neurosciences,  2012, 35(10):587-596). 
     Kappa opioid receptors, interacting with the dynorphin system in the CNS, also appear to play a significant role in other psychiatric disorders, including anxiety (e.g., see Tejeda, H. A., et al,  Cellular and Molecular Life Science,  2011, 69:857-896; Peters, M. F., et al,  European Journal of Pharmacology,  2011, 661:27-34) and therefore KOR agonists or antagonists may offer a therapeutic value in treating anxiety disorders. 
     KOR antagonists have been disclosed, e.g., in U.S. Pat. No. 6,534,514 (Portoghese, P. S., et al, Issued Mar. 18, 2003), U.S. Pat. No. 6,559,159 (Carroll, F. I., et al, Issued May 6, 2003) and U.S. Pat. No. 7,709,522 (Buezo, N. D., et al, Issued May 4, 2010). Similarly, kappa agonists have been disclosed in U.S. Pat. No. 5,804,595 (Portoghese, P. S., et al, Issued Sep. 8, 1998) and U.S. Pat. No. 6,191,126 (Gamache, D. A.; Issued Feb. 20, 2001). The syntheses and receptor selectivities of novel chemotypes which exhibit potent antagonist or agonist activity at the KOR have also been described by K. J. Frankowski, et al ( ACS Chemical Neuroscience,  2012, 3:221-236), C. H. Mitch, et al ( Journal of Medicinal Chemistry,  2011, 54:8000-8012), T. E. Prisinzano, ( Journal of Medicinal Chemistry,  2013, 56:3435-3443) and C. M. Kormos, et al, ( Journal of Medicinal Chemistry,  2013, 56:4551-4567). T. A. Brugel, et al ( Bioorganic and Medicinal Chemistry Letters,  2010, 20:5405-5410 and 20:5847-5852) have also disclosed a novel series of azabicyclo[3.2.1]octan-3-yloxy-benzamides with potent and selective K antagonist activity. 
     It has recently been reported that the biotech company Alkermes has initiated a Phase 2 study of ALKS 5461, a combination of buprenorphine (a mixed kappa opioid receptor antagonist/ mu opioid receptor agonist which has demonstrated antidepressant properties in human studies) and ALKS 33 (i.e., samidorphan), a selective mu opioid receptor antagonist that does not affect the delta- or kappa- opioid receptors) in clinical trials of patients suffering from major depressive disorder (http://en.wikipedia.org/w/index.php?title=Samidorphan&amp;oldid =555540304). 
     Recently, there has also been increased awareness of the potential for compounds which function as sigma-1 receptor ligands. Such ligands have been shown to modulate NMDA and dopamine neurotransmission in animal studies, suggesting utility for treatment of psychiatric diseases including depression (Debonnel G, de Monitgny C,  Life Sciences  (1996) 58(9):721-734), schizophrenia and OCD (e.g., see Ishikawa M, Hashimoto K, J.  Receptor, Ligand and Channel Res.  (2010) 3:25-36; Cobbs E J, Entrena J M, Nieto F R, Cendan C M and del Pozo E,  Current Neuropharmacology  (2008) 6:344-366); Hayashi T, Su TP,  CNS Drugs  (2004) 18(5):269-284). Clinical improvement of cognitive symptoms in schizophrenic patients has been observed through concomitant use of sigma-1 receptor agonists like fluvoxamine and donepezil (Niitsu T, Hashimoto K,  Curr. Pharm. Des.,  (2012) 18(7):857-883). Others have suggested a role in the treatment of Alzheimer&#39;s Disease through regulation of neurite outgrowth (Kimura Y, Fujita Y, Yamashita T,  Receptors  &amp;  Clinical Investigation  (2014) 1:8-12). 
     The present invention relates to the use of novel cycloalkyl-diamines and to their pharmaceutical compositions in the treatment of psychiatric disorders from the group consisting of depression, mood disorders, anxiety, schizophrenia, bipolar disorder (also referred to as manic-depressive disorder), addiction, cognitive impairment, Parkinson&#39;s and Alzheimer&#39;s diseases in mammals, including humans. Many of the compounds disclosed in this application exhibit affinity for the kappa opioid receptor and, in some cases, demonstrate significant activity as sigma-1 ligands. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a method for the treatment of psychiatric disorders in mammals, including humans, by administering a compound of the formula I, or a pharmaceutically effective salt(s) thereof, in an amount which is effective at inhibiting the growth of the cancer cells and carcinomas in said mammal, wherein: 
     
       
                 
         
             
             
         
      
     
     X and Y are independently selected from the group consisting of H, F, CI, Br, I, CN, OH, CF 3 , C 2 F 5 , C 1 -C 6 -alkyl, C 3 -C 7 -cycloalkyl, C 1 -C 3 -alkoxy, aryl, heteroaryl, —(—C=O)—R5, —NH—(C=O)—R5, —NR5—(C=O)—R6, —(C=O)—NHR5 and —(C=O)—NR5R6; 
     R1 is hydrogen; 
     R2 is hydrogen or C 1 -C 6 -alkyl; 
     R3 is hydrogen or C 1 -C 6 -alkyl; 
     R4 is selected from the group consisting of C 1 -C 6 -alkyl, C 3 -C 7 -cycloalkyl, (CH 2 ) n , —R7, or 
     NR3R4 is a 5- to 12-membered cyclic or bicyclic ring system containing up to two additional heteroatoms in the ring, selected from N, O and S; 
     R5 is selected from C 1 -C 6 -alkyl and aryl; 
     R6 is selected from C 1 -C 6 -alkyl and aryl, or 
     NR5R6 is a 5- to 12-membered cyclic or bicyclic ring system containing up to two additional heteroatoms in the ring, selected from N, O and S; 
     R7 is independently selected from the group consisting of H, C 1 -C 6 -alkyl, C 3 -C 7 -cycloalkyl, (C 1 -C 6 -alkyloxy)—, (C 1 -C 6 -alkyloxy)—(C 1 -C 6 -alkyl)—, NR8R9—, NR8R9—(C 1 -C 6 -alkyl), aryl, heterocyclyl and heteroaryl; 
     R8 and R9 are independently selected from hydrogen, C 1 -C 6 -alkyl and aryl, or taken together with the N atom to which they are attached form a 3- to 8-membered ring containing up to two additional heteroatoms, selected from N, O and S; and 
     n is an integer between 0 and 6. 
     Preferred Embodiments of the Present Invention Include the Compounds of Formula I in which:
     (A) R2 is methyl, R1 and R3 are hydrogen, Y is hydrogen;   X is halogen;   n is an integer between 0 to and 6; and   R7 is aryl or heteroaryl.   (B) R2 is methyl, R1 and R3 are hydrogen; Y is hydrogen;   X is halogen;   n is an integer between 0 to and 6; and   R7 is heterocyclyl.   (C) R2 is methyl; R1 and R3 are hydrogen; Y is hydrogen;   X is halogen;   n is an integer between 0 to and 6; and   R7 is NR8R9.
 
Preferred compounds of formula I in accordance with the present invention include:
   trans-1-(2-chlorophenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -cyclopropyl-N 1 -methylcyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -cyclopropyl-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -cyclopentyl-N 1 -methylcyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -cyclopentyl-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -(3-methoxypropyl)-N 1 -methylcyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -(3-methoxypropyl)-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 1 -methyl-N 2 -(tetrahydrofuran-2-ylmethyl)cyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 1 -methyl-N 2 -(tetrahydrofuran-2-ylmethyl)cyclohexane-1,2-diamine;   cis-1-(2-chloropheny)-N 2 -(3-(dimethylamino)propyl)-N 1 -methylcyclohexane-1,2-diamine;   trans-N 2 -benzyl-1-(2-chlorophenyl)-N 1 -methylcyclohexane-1,2-diamine;   cis-N 2 -benzyl-1-(2-chlorophenyl)-N 1 -methylcyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 1 -methyl-N 2 -(pyridin-4-ylmethyl)cyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 1 -methyl-N 2 -(pyridin-3-ylmethyl)cyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -(1-(R)-phenyl)-ethyl)-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -(1-(S)-phenyl)-ethyl)-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -(3-(1-imidazolyl)-propyl)-N 1 -methylcyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -(3-(1-imidazolyl)-propyl)-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -(1-ethyl-pyrrolidin-2-ylmethyl)-N 1 -methylcyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -(1-ethyl-pyrrolidin-2-ylmethyl)-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -(3-(pyrrolidin-1-yl)propyl)-N 1 -methylcyclohexane-1,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -(3-(pyrrolidin-1-yl)propyl)-N 1 -methylcyclohexane-1,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -(3-phenylpropyl)-N 1 -methylcyclohexane-1 ,2-d iamine;   cis-1-(2-chlorophenyl)-N 2 -(3-phenylpropyl)-N 1 -methylcyclohexane-1 ,2-d iamine;   trans-1-(2-chlorophenyl)-N 2 -(3-(morpholin-1-yl)propyl)-N 1 -methylcyclohexane-1 ,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -(3-(morpholin-1-yl)propyl)-N 1 -methylcyclohexane-1 ,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -(3-(4-methylpiperazin-1-yl)propyl)-N 1 -methylcyclohexane-1 ,2-diamine;   cis-1-(2-chlorophenyl)-N 2 -(3-(4-methylpiperazin-1-yl)propyl)-N 1 -methylcyclohexane-1 ,2-diamine;   trans-1-(2-chlorophenyl)-N 2 -cyclohexyl-N 1 -methylcyclohexane-1 ,2-diamine; and   cis-1-(2-chlorophenyl)-N 2 -cyclohexyl-N 1 -methylcyclohexane-1 ,2-diamine.   

     Other compounds of the invention include the following:
     1-(2-chloro-4-methoxyphenyl)-N 2 -[3-(4,5-dimethyl-1H-imidazol-2-yl)propyl]-N 1 -methyl-cyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 1 -methyl-N 2 -[-3-(1H-1,2,4-triazol-5-yl)propyl]-cyclohexane-1,2-diamine;   1-(2-methylphenyl)-N 1 -methyl-N 2 -[3-(3-methyl-1H-1,2,4-triazol-5-yl)propyl]-cyclohexane-1,2-diamine;   1-(2,4-dichlorophenyl)-N 1 -methyl-N 2 -[3-(1H-tetrazol-5-yl)propyl]-cyclohexane-1,2-diamine;   1-(3,4-fluorophenyl)-N 1 -methyl-N 2 -[2-(1-methyl-1H-tetrazol-5-yl)ethyl]cyclohexane-1,2-diamine;   1-(4-chlorophenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2,4-dichlorophenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(3,4-difluorophenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(4-isopropylphenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2-methoxyphenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -[3-(1H-imidazol-2-yl)propyl]N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -[2-(1H-imidazol-2-yl)ethyl]N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 1 -methyl-N 2 -[3-(1,3-thiazol-2-yl)propyl]cyclohexane-1,2-diamine;   1-(3,5-dimethyl-2-chlorophenyl)-N 1 -methyl-N 2 -[3-(1,3-thiazol-2-yl)propyl]-cyclohexane-1,2-diamine;   1-(3,5-dimethyl-phenyl)-N 1 -methyl-N 2 -[3-(4,5-dimethyl-1,3-thiazol-2-yl)propyl]-cyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -[3-(1,3-benzothiazol-2-yl)propyl]N 1 -methylcyclohexane-1,2-diamine;   1-(2,3-dichlorophenyl)-N 2 -[3-(1,3-benzimidazol-2-yl)propyl]-N 1 -methylcyclohexane-1,2-diamine;   1-(3,4-dichlorophenyl)-N 2 -(2-(3,4-difluorophenyl)ethyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -(3-(3,4-difluorophenyl)propyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -(3-(4-fluorophenyl)propyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -(3-(3,4-dichlorophenyl)propyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -(3-(3,4-dimethoxyphenyl)propyl)-N 1 -methylcyclohexane-1,2-diamine;   1-(2-chlorophenyl)-N 2 -[(4,5-dimethyl-1H-imidazol-2-yl)methyl]-N 1 -ethylcyclohexane-1,2-diamine; and 1-(2-chlorophenyl)-N 1 -ethyl-N 2 -[(1-methyl-1H-imidazol-2-yl)methyl]cyclohexane-1,2-diamine.   

    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The compounds of formula I may be prepared as described in the following reaction schemes and discussions. Unless otherwise indicated, X, Y, R1, R2, R3, R4, R5, R6, R7 and structural formulae II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV and XV in the reaction schemes and discussion that follow are defined as above. 
     
       
                 
         
             
             
         
      
     
     According to Scheme 1, a ketone of the general formula II, wherein X, Y, R 1  and R 2  are as previously defined, may be converted directly into the corresponding compound of the formula I, via an intermediate of the general formula IV, by reacting it with one or more equivalents of an primary amine of the general formula III in the presence of a reducing reagent. Reducing reagents that may be used include sodium cyanoborohydride, sodium triacetoxyborohydride, sodium borohydride, lithium aluminum hydride, hydrogen plus a metal catalyst, zinc plus hydrochloric acid, and formic acid. This reaction is typically conducted in a reaction inert solvent at a temperature from about 0° C. to about 150° C., but may be conducted in the absence of solvent. Suitable reaction inert solvents include lower alcohols (e.g., methanol, ethanol, isopropanol), 1,2-dichloroethane, acetic acid and tetrahydrofuran (THF)). Preferably the reaction is conducted with an excess of the corresponding amine III, in the absence of additional solvent, at a temperature of about 110° C., and using the reducing agent sodium cyanoborohydride. 
     Alternatively, the reaction of a compound of formula II with an amine compound of the formula III may be carried out in the presence of a dehydrating agent (e.g., titanium tetrachloride) or by using an apparatus designed to azeotropically remove the water generated, to produce an imine of the formula IV. This imine may then be converted to the title product of formula I by reduction of the C=N bond with a reducing agent as described above, preferably with sodium cyanoborohydride in the presence or absence of a suitable, reaction inert solvent as described in the preceding paragraph at a temperature of about 0° C. to about 150° C. and preferably at about 110° C. Other suitable dehydrating agents/solvent systems include titanium tetrachloride in dichloromethane, titanium isopropoxide in dichloromethane and activated molecular sieves in toluene or in dichloromethane. 
     
       
                 
         
             
             
         
      
     
     When a secondary amine of the general formula V (i.e., HNR3R4) is used, an alternative method involves the formation of an enamine of general formula VI, which can be reduced to the title product of formula I through the use of a selective reducing agent or selective reduction conditions known to one familiar with the art of organic synthesis. Using this procedure, as shown in Scheme 2 above, the intermediate enamine VI may be isolated and purified if it is stable, or it may be used directly in the reduction step to generate the diamine of general formula I. Selective reducing agents and reagents to facilitate the conversion of intermediate VI to the compounds of formula I include: formic acid, hydrogen gas and a metal catalyst (e.g., Pd on carbon, Pt on carbon). 
     In another method (Scheme 3) for the preparation of the compounds of the present invention, an intermediate oxime (VII) can be prepared through reaction of the starting ketone I and hydroxylamine. Synthesis of such oximes is well precedented in the chemical literature (e.g., see LaMattina J L, et al,  Synthesis  (1980) 329-330), and it is also known that intermediate oximes like VII are capable of forming two different isomers, denoted as Z- and E-oximes. These isomers 
                                
may or may not react differently in their subsequent conversion to intermediates of general formulae VIII (i.e., I, R3, R4 =H), and one of the oxime isomers may be less reactive or resistant to reduction to intermediate VIII. The reduction to VIII can be achieved using one of a variety of reagents and procedures, including Zn—AcOH, Na and C 2 H 5 OH, BH 3 , and NaBH 3 CN—TiCl 3.  
 
     In the next step, compound VIII can be converted to a compound of general formula X by subjecting it to a reductive amination with an aldehyde of general formula IX (for examples, see Jerry March, “Advanced Organic Chemistry: Reactions, Mechanisms and Structure”, 4 th  Ed., John Wiley &amp; Sons, New York, N.Y. (1992) pp 898-900) followed by alkylation of the nitrogen atom of the intermediate of general formula X with a reagent of general formula R9-L, where L is a leaving group (e.g., Cl, Br, mesylate) and R9 is C 1 -C 3  alkyl. Procedures for these reactions are readily available in the chemical literature and familiar to chemists with skill in the art of organic synthesis. 
     The starting ketone for the above processes, compound II, may be obtained from commercial sources or may be synthesized as described in the chemical literature (Scheme 4). Such compounds may exist as racemic mixtures or as the individual (+)- and (−)- isomers. 
     In general, 1-bromo-cyclopentane is converted to a Grignard reagent (XI) by reaction with magnesium metal in an inert solvent, typically in ethers like diethyl ether or tetrahydrofuran (THF). The Grignard reagent so formed is then reacted with an appropriately substituted arylnitrile (XII), in an inert solvent such as hexane, and stirred at room temperature until the reaction is determined to have been completed. The product, the arylketone (XIII), dissolved in a suitable solvent (e.g., chloroform) is then treated with one equivalent of bromine (Br 2 ), and the resulting α-bromo-ketone (XIV) is isolated by filtration. Compound XIV is then added to a primary amine of general formula R2—NH 2  in an inert solvent (e.g., toluene) and the mixture is heated to reflux. The 
                                
solvents are subsequently removed under vacuum to obtain the crude α-hydroxy-imine (XV). This intermediate is then heated, typically in a high-boiling, inert solvent (e.g., decalin) wherein the compound undergoes a thermal rearrangement to produce the α-amino-ketone (II).
 
     Specifically, the compound II in which X is 2-chloro, Y is H, R1 is hydrogen and R2 is methyl is commonly referred to as ketamine. Ketamine is a Central Nervous System active drug that may interact with NMDA (i.e., N-Methyl-D-Aspartate) receptors in the brain and has been associated with a variety of behavioral disorders in human and animal studies. The synthesis and utility of ketamine and related analogs as NMDA receptor modulators and disease treatments are described by T. G. Gant and S. Sarshar in U.S. patent application 2008/109958 (Apr. 25, 2008). 
     The compounds of the present invention may have optical centers and therefore may occur in different enantiomeric configurations. Formula I, as depicted above, includes all enantiomers, diastereomers, and other stereoisomers of the compounds depicted in structural formula I, as well as racemic and other mixtures thereof. Individual isomers can be obtained by known methods, such as optical resolution, optically selective reaction, or chromatographic separation in the preparation of the final product or its intermediate. 
     Where cis- and trans- isomers are possible (i.e., at positions “a” and “b” in structure formula I), for an embodiment of the inventive compounds of formula I, both cis- and trans-isomers (i.e., diastereomers) are within the scope of this invention. 
     The present invention also includes isotopically labeled compounds, which are identical to those recited in formula I, 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 present invention include isotopes of hydrogen, carbon, nitrogen, oxygen, sulfur, phosphorus, fluorine, and chlorine, such as  2 H,  3 H,  11 C,  13 C,  13 N,  15 N,  18 O,  35 S,  31 P,  33 P,  18 F and  37 Cl, respectively. 
     Compounds of the present invention, prodrugs thereof, and pharmaceutically acceptable salts of said compounds, or of said prodrugs which contain the aforementioned isotopes and/or other isotopes of other atoms are within the scope of this invention. Certain isotopically labeled compounds of the present invention, for example, those into which radioactive isotopes such as  3 H and  14 C are incorporated, are useful in drug and/or substrate tissue distribution assays. Tritiated, i.e.,  3 H, and carbon—14, i.e.,  14 C, isotopes are particularly preferred for their ease of preparation and detectability. Further, substitution with heavier isotopes such as deuterium, i.e.,  2 H, can afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements and, hence, may be preferred in some circumstances. Isotopically labeled compounds of formula I of this invention and prodrugs thereof can generally be prepared by carrying out the procedures disclosed in the Schemes and/or in the Examples and Preparations below, by substituting a readily available isotopically labeled reagent for a non-isotopically labeled reagent. 
     The term “alkyl” refers to straight or branched chains of carbon atoms. Exemplary alkyl groups are C 3 -C 10  alkyl groups which include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl and the like, including all regioisomeric forms thereof, and straight and branched chain forms thereof. The term “alkyl” is also used to denote straight or branched chains of carbon atoms having one or more carbon-carbon double bonds, such as vinyl, allyl, butenyl and the like, as well as straight and branched chains of carbon atoms having one or more carbon-carbon triple bonds, such as ethynyl, propargyl, butynyl, and the like. 
     The term “aryl” denotes a cyclic, aromatic hydrocarbon. Examples include phenyl, naphthyl, anthracenyl, phenanthracenyl. Such aryl groups may further be substituted at available positions with H, F, Cl, Br, I, CN, OH, alkoxy, NO 2 , NH 2 , NH-alkyl or N-dialkyl. 
     The terms “alkoxy” and “aryloxy” denote “O-alkyl” and “O-aryl”, respectively. The term “cycloalkyl” denotes a cyclic group of carbon atoms, where the ring formed by the carbon atoms may be saturated or may comprise one or more carbon double bonds in the ring. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like as well as cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl, and the like. As used herein, the term “cycloalkyl” is also intended to denote a cyclic group comprising at least two fused rings, such as adamantyl, decahydronaphthalinyl, norbornanyl, where the cyclic group may also have one or more carbon-carbon double bonds in one or more rings, such as in bicyclo(4.3.0)nona-3,6(1)-dienyl, dicyclopentadienyl, 1,2,3,4-tetrahydro-naphthalinyl (i.e., tetralinyl), indenyl, and the like. 
     The term “halogen” represents chloro, fluoro, bromo and iodo. 
     The term “heteroaryl” denotes a monocyclic or bicyclic aromatic group wherein one or more carbon atoms are replaced with heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur. If the heteroaryl group contains more than one heteroatom, the heteroatoms may be the same or different. Preferred heteroaryl groups are five- to fourteen-member rings that contain from one to three heteroatoms independently selected from oxygen, nitrogen, and sulfur. Examples of preferred heteroaryl groups include, but are not limited to, benzo[b]thienyl, chromenyl, furyl, imidazolyl, indazolyl, indolizinyl, indolyl, isobenzofuranyl, isoindolyl, isoquinolinyl, isothiazolyl, isoxazolyl, napthylidinyl, oxadiazolyl, oxazinyl, oxazolyl, phthalazinyl, pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridinyl, triazolyl and tetrazolyl, said heteroaryl groups may be further substituted as described above in the definition of aryl. 
     A “unit dosage form” as used herein is any form that contains a unit dose of the compound of formula I. A unit dosage form may be, for example, in the form of a tablet or a capsule. The unit dosage form may also be in liquid form, such as a solution or suspension. 
     The compositions of the present invention may be formulated in a conventional manner using one or more pharmaceutically acceptable carriers. Thus, the active compounds of the present invention may be formulated for oral, buckle, intranasal, parenteral (e.g., intravenous, intramuscular or subcutaneous) or rectal administration or in a form suitable for administration by inhalation or insufflations. 
     For oral administration, the pharmaceutical compositions may take the form of, for example, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g., pre-gelatinized maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose), fillers (e.g., lactose, microcrystalline cellulose or calcium phosphate); lubricants (e.g., magnesium stearate, talc, or silica); disintegrants (e.g., potato starch or sodium starch glycolate); or wetting agents (e.g., sodium lauryl sulfate). The tablets may be coated by methods well known in the art. Liquid preparations for oral administration may take the form of, for example, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, methyl cellulose or hydrogenated edible fats); emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters or ethyl alcohol); and preservatives (e.g., methyl or propyl p-hydroxybenzoates or sorbic acid). 
     For buccal administration, the composition may take the form of tablets or lozenges formulated in conventional manner. 
     The active compounds of the invention may be formulated for parenteral administration by injection, including using conventional catheterization techniques or infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulating agents such as suspending, stabilizing and/or dispensing agents. Alternatively, the active ingredient may be in powder form for reconstitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use. 
     The active compounds of the invention may also be formulated in rectal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides. 
     For intranasal administration by inhalation, the active compounds of the invention are conveniently delivered in the form of a solution or suspension from a pump spray container that is squeezed or pumped by the patient or as an aerosol spray presentation from a pressurized container or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichloro-fluoromethane, dichlorotetrachloroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol, the dosage unit may be determined by providing a valve to deliver a metered amount. The pressurized container or nebulizer may contain a solution or suspension of the active compound. Capsules and cartridges (made, for example, from gelatin) for use in an inhaler or insulator may be formulated containing a powder mix of a compound of the invention and a suitable powder base such as lactose or starch. 
     A proposed dose of the active compounds of the invention for oral, parenteral or buccal administration to the average adult human for the treatment of the conditions referred to above is from about 0.1 mg/kg to about 100 mg/kg of the active ingredient per unit dose which could be administered, for example, one to four times per day. Toxicity concerns at the higher level may restrict intravenous (i.v.) dosages to a lower level, such as up to 10 mg/kg. A dose of about 0.1 mg/kg to about 100 mg/kg may be employed for oral (p.o.) administration. Typically, a dosage from about 0.1 mg/kg to about 10 mg/kg may be employed for intramuscular (i.m.) injection. Preferred dosages are in the 1.0 mg/kg to about 100 mg/kg range, and more preferably in the 5 mg/kg to about 50 mg/kg range for i.v. or p.o. administration. The duration of the treatment is usually once per day for a period of one days to three weeks, or until the condition is essentially brought under control. 
     Aerosol formulations for treatment of the conditions referred to above in the average human are preferably arranged such that each metered dose or “puff” of aerosol contains 0.1 micrograms to 100 micrograms of the active compound of the invention. The overall daily dose with an aerosol will be within the range of 0.1 mg/kg to about 100 mg/kg, and preferably in the range of 1.0 mg/kg to about 25 mg/kg. Administration may be several times daily, for example 2, 3, 4 or 8 times, giving for example 1, 2 or 3 doses each time. 
     As an example, the mammal in need of treatment or prevention may be a human. As another example, the mammal in need of treatment or prevention may be a mammal other than a human. 
     A compound of formula I which is basic in nature is capable of forming a wide variety of different salts with various inorganic and organic acids. The acid additions salts are readily prepared by treating the base compounds with a substantially equivalent amount of the chosen mineral or organic acid in an aqueous solvent medium or in a suitable organic solvent such as methanol or ethanol. Upon careful evaporation of the solvent, the desired solid salt is obtained. 
     The acids which are used to prepare the pharmaceutically acceptable acid salts of the active compound used in formulating the pharmaceutical composition of this invention that are basic in nature are those which form non-toxic acid addition salts, e.g., salts containing pharmacologically acceptable anions. Non-limiting examples of the salts include the acetate, benzoate, beta-hydroxybutyrate, bisulfate, bisulfite, bromide, butyne-1,4-dioate, caproate, chloride, chlorobenzoate, citrate, dihydrogen phosphate, dinitrobenzoate, fumarate, glycollate, heptanoate, hexyne-1,6-dioate, hydroxybenzoate, iodide, lactate, maleate, malonate, mandelate, metaphosphate, methanesulfonate, methoxybenzoate, monohydrogen phosphate, naphthalene- 1-sulfonate, naphthalene-2-sulfonate, oxalate, phenyl butyrate, phenyl propionate, phosphate, phthalate, phenylacetate, propanesulfonate, propiolate, propionate, pyrophosphate, pyrosulfate, sebacate, suberate, succinate, sulfate, sulfite, sulfonate, tartrate, xylenesulfonate, acid phosphate, acid citrate, bitartrate, succinate, gluconate, saccharate, nitrate, methanesulfonate, and pamoate {i.e., 1,1′-methylene-bis-(2-hydroxy-3-naphthoate)] salts. 
     Also included within the scope of this invention are solvates and hydrates of compounds of formula I and their pharmaceutically acceptable salts. The present invention includes within its scope all possible stoichiometric and non-stoichiometric forms. 
     In the examples that follow, the abbreviations used in this document are intended to have the following, general meaning:
     bm: broad multiplet (NMR)   bs: broad singlet (NMR)   d: doublet (NMR)   dd: doublet of doublets (NMR)   d.e.: diatomaceous earth, filtering agent   calcd.: calculated value   J: coupling constant (NMR)   LC: high pressure liquid chromatography (HPLC)   m: multiplet (NMR)   min: minute(s)   m/z: mass to charge ratio (mass spectroscopy)   obsd: observed value   Rf: retention factor (chromatography)   RT: retention time (chromatography)   rt: room temperature (typically 25° C.)   s: singlet (NMR)   t: triplet (NMR),   T: temperature   tlc: thin layer chromatography   TFA: trifluoroacetic acid   THF: tetrahydrofuran   

     Solvents were purchased and used without purification. Yields were calculated for material judged to be homogeneous by thin layer chromatography and NMR. Thin layer chromatography was performed on Kieselgel plates eluting with the indicated solvents, visualized by using a 254 nm UV lamp, and stained with either an aqueous KMnO 4  solution or an ethanolic solution of 12-molybdophosphoric acid. 
     Nuclear Magnetic Resonance (NMR) spectra were acquired on a 400 MHz NMR Spectrometer. Chemical shifts for proton  1 H—NMR spectra are reported in parts per million (ppm) relative to the singlet of CDCl 3  at 7.24 ppm. 
     Preparative conditions for Chromatographic Purification and Analysis. 
     Instrument: LaChrom HPLC system (Merck-Hitachi) for UV-directed purification and Waters HPLC/MS for mass directed purification, both equipped with RP C 18  column (Phenomenex Gemini NX 5 μ 150 mm x 30 mm). 
     Eluent I:
     A: Acetonitrile-H 2 O=5:95, 10 mM NH 4 HCO 3  buffer, pH 8.0   B: Acetonitrile-H 2 O=80:20 10 mM NH 4 HCO 3  buffer, pH 8.0   

     Eluent II:
     A: Acetonitrile-H 2 O=5:95, 20 mM HCOONH 4 /NH 4 OH buffer, pH 7.4   B: Acetonitrile-H 2 O=80:20, 20 mM HCOONH 4 /NH 4 OH buffer, pH 7.4   

     Eluent III:
     A: Acetonitrile-H 2 O=5:95, 20 mM CH 3 COONH 4 /CH 3 COOH buffer, pH 6   B: Acetonitrile-H 2 O=80:20, 20 mM CH 3 COONH 4 /CH 3 COOH buffer, pH 6   

     Eluent IV:
     A: H 2 O with 0.1% TFA, pH 2.2   B: Acetonitrile with 0.1% TFA, pH 2.2   

     Gradient Program: adjusted according to the compound properties 
     Column Temp.: room temperature (25° C.) 
     Flow Rate: up to 40 ml/min 
     Detection and triggering: UV detector (220 nm) 
     Conditions for LC-MS analysis: 
     Column: Zorbax RRHD Eclipse XDB (Agilent) C 18 , 1.9 micron, 50 mm x 2.1 mm. 
     Eluent I:
     A: Acetonitrile-H 2 O=5:95, 20 mM HCOONH 4 /NH 4 OH buffer, pH 7.4   B: Acetonitrile-H 2 O=80:20, 20 mM HCOONH 4 /NH 4 OH buffer, pH 7.4   

     Eluent I:
     A: H 2 with 0.1% TFA, pH 2.2   B: Acetonitrile with 0.1% TFA, pH 2.2   

     Gradient Program: adjusted according to the compound properties; typically, start: 0% B to 100% B in 1 minute, 0.8 minute isocratic B. 
     Column Temp.: 40° C. 
     Flow Rate: 0.6 mL/min 
     Sample Conc.: ca. 1 mg/mL 
     Sample Solvent: Acetonitrile 
     Injection: 0.5 μL 
     Detection wavelength: 220 nm
     MS Conditions:   

     Measured Mass Range: 100-750 Daltons 
     Scan Time: 0.2 s 
     Ion mode: ES± 
     Cone Voltage: 20 V 
     Capillary Voltage: 3 V 
     Source temp.: 140° C. 
     Desolvation temp.: 450° C. 
     Desolvation Gas: 450L/h 
     Cone Gas: 60 L/h 
     EXAMPLE 1   
     (GENERAL PROCEDURE A) 
     Trans-1-(2-chlorophenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine (1 a ) and 
     Cis-1-(2-chlorophenyl)-N 2 -(2-(dimethylamino)ethyl)-N 1 -methylcyclohexane-1,2-diamine ( b ). 
     A mixture of 2-(2-chlorophenyl)-2-(methylamino)cyclohexanone hydrochloride (ketamine HCl) (423 mg, 1.54 mmol) and N 1 ,N 1 -dimethylethane-1,2-diamine (1.6 mL, 19.2 mmol) was heated at 110° C. for 20 h. The mixture was cooled to room temperature and sodium cyano-borohydride (490 mg, 7.8 mmol) was added. The mixture was then heated at 110° C. overnight. The cooled reaction mixture was quenched with saturated NaHCO 3 , extracted with CH 2 Cl 2  (75 mL), dried (Na 2 SO 4 ) and concentrated to dryness to give 500 mg of crude product (M/Z 310 [M + +H]). This material was further purified by column chromatography, as described in Method A above. 
     a.) The product fractions, (RT=0.50) were combined, the solvents were removed and the trans- isomer was isolated as a trifluoroacetate salt, 0.149 g. 
     MS: calcd. for C 17 H 28 CIN 2 : 309.9; obsd.: 309.2 (m+1). 
       1 H—nmr (DMSO—d 6 , 400 MHz, T=30° C.) δ 1.4-1.7 (m, 3H), 1.75-2.0 (m, 3H), 2.10-2.35 (m +s, 5H), 2.40-2.50 (m+s, 6H), 2.75-2.85 (m, 2H), 2.92 (m, 1H), 3.15 (m, 1H), 7.40-7.50 (m, 2H), 7.55-7.65 (m, 2H), 8.5 (bs, 1H). 
     b.) The more polar fractions (RT=0.64) were separately combined and, after removal of the solvents, the cis- isomer was isolated as a solid, 0.078 g. 
     MS: calcd. for C 17 H 28 CIN 3 : 309.9; obsd.: 309.19 (m+1). 
     The following compounds were also prepared using the general procedure A, as described above for the title compounds of Examples 1: 
     EXAMPLE 2   
     Trans- 1-(2-chlorophenyl) -N 2 -cyclopropylmethyl-N 1 -methylcyclohexane- 1,2-diamine (2 a ), and 
     Cis- 1-(2-chlorophenyl)-N 2 -cyclopropylmethyl-N 1 -methylcyclohexane- 1,2-diamine (2 b ). 
     The title compounds of Example 2 were prepared according to general procedure A using cyclopropylmethanamine and ketamine. 
     a.) LC (RT=0.55)/Mass spectrum (m/z) calcd. for C 17 H 25 CIN 2 : 292.8; obsd.: 293 (M+1, 100%), 295 (M+1, 37Cl, 30%), 262 (28%). 
       1 H—nmr (DMSO—d 6 , 400 MHz, T=30° C.) δ 0.1 (m, 2H), 0.2 (m, 2H), 0.5 (m, 2H), 0.85 (m, 1H), 1.50 (m, 2H), 1.65 (d, 1H), 1.85-2.10 (m, 2H), 2.05 (s, 3H), 2.15 (m, 2H), 2.30-2.55 (m, 2H), 2.70 (dd, 1H), 4.45 (s, 1H), 7.40-7.65 (m, 4H). 
     b.) LC (RT=0.72)/MS: calcd. for C 17 H 25 CIN 2 : 292.8; obsd.: 293 (M+1). 
       1 H—nmr (DMSO—d6, 400 MHz, T=30° C.) δ 0.30 (m, 2H), 0.55 (dd, 2H), 1.0 (m, 1H), 1.2 (m, 1H), 1.40-1.85 (m, 5H), 2.05 (m+s, 4H), 2.80 (m, 3H), 4.20 (m, 1H), 6.5 (bs, 2H), 7.35-7.50 (m, 2H), 7.52 (dd, 1H), 7.64 (d, 1H). 
     EXAMPLE 3   
     Trans-1-(2-chlorophenyl)-N 2 -cyclopentyl-N 1 -methylcyclohexane-1,2-diamine (3 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -cyclopentyl-N 1 -methylcyclohexane-1,2-diamine (3 b ). 
     The title compounds of Example 3 were prepared according to general procedure A using cyclopentylamine and ketamine. 
     a.) LC (RT=0.58)/MS: calcd. for C 18 H 27 CIN 2 : 306.9; obsd.: 306.19 (m+1). 
     b.) LC (RT=0.96)/MS: calcd. for C 18 H 27 CIN 2 : 306.9; obsd.: 306.19 (m+1). 
     EXAMPLE 4   
     Trans-1-(2-chlorophenyl)-N 2 -(3-methoxypropyl)-N 1 -methylcyclohexane-1,2-diamine (4 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -(3-methoxypropyl)-N 1 -methylcyclohexane-1,2-diamine (4 b ). 
     The title compounds of Example 4 were prepared according to general procedure A using 3-methoxypropylamine and ketamine. 
     a.) LC (RT=0.59)/MS: calcd. for C 17 H 27 CIN 2 O: 310.9; obsd.: 310.18 (m+1). 
     b.) LC (RT=0.67)/MS: calcd. for C 17 H 27 CIN 2 O: 310.9; obsd.: 310.18 (m+1). 
     EXAMPLE 5   
     Trans-1-(2-chlorophenyl)-N 1 -methyl-N 2 -(tetrahydrofuran-2-ylmethyl)cyclohexane-1,2-diamine (5 a ), and 
     Cis-1-(2-chlorophenyl)-N 1 -methyl-N 2 -(tetrahydrofuran-2-ylmethyl)cyclohexane-1,2-diamine (5 b ). 
     The title compounds of Example 5 were prepared according to general procedure A using 2-aminomethyl-2,3,4,5-tetrahydrofuran and ketamine. 
     a.) LC (RT=0.63)/MS: calcd. for C 18 H 27 CIN 2 O: 322.9; obsd.: 322.18 (m+1). 
     b.) LC (RT=0.70)/MS: calcd. for C 18 H 27 CIN 2 O: 322.9; obsd.: 322.18 (m+1). 
     EXAMPLE 6   
     Cis-1-(2-chloropheny)-N 2 -(3-(dimethylamino)propyl) N 1 -methyl-cyclohexane-1,2-diamine (6). 
     The title compound of Example 6 was prepared according to general procedure A using 3-(N,N-dimethylamino)-propylamine and ketamine. 
     LC (RT=0.66)/MS: calcd. for C 18 H 30 CIN 36 : 323.9; obsd.: 323.21 (m+1). 
     EXAMPLE 7   
     Trans-N 2 -benzyl-1-(2-chlorophenyl)-N 1 -methylcyclohexane-1,2-diamine (7 a ) and 
     Cis-N 2 -benzyl-1-(2-chlorophenyl)-N 1 -methylcyclohexane-1,2-diamine (7 b ). 
     The title compounds of Example 7 were prepared according to general procedure A using benzylamine and ketamine. 
     a.) LC (RT=0.66)/MS: calcd. for C 20 H 25 CIN 2 : 328.9; obsd.: 328.17 (m+1). 
     b.) LC (RT=1.01)/MS: calcd. for C 20 H 25 CIN 2 : 328.9; obsd.: 328.17 (m+1). 
     EXAMPLE 8   
     Cis-1-(2-chlorophenyl)-N 1 -methyl-N 2 -(pyridin-4-ylmethyl)cyclohexane-1,2-diamine (8). 
     The title compound of Example 8 was prepared according to general procedure A using 4-(aminomethyl)-pyridine and ketamine. 
     LC (RT=0.70)/MS: calcd. for C 19 H 24 CIN 3 : 329.9; obsd.: 329.17 (m+1). 
     EXAMPLE 9   
     Trans-1-(2-chlorophenyl)-N 1 -methyl-N 2 -(pyridin-3-ylmethyl)cyclohexane-1,2-diamine (9). 
     The title compound of Example 9 was prepared according to general procedure A using 3-(aminomethyl)-pyridine and ketamine. 
     LC (RT=0.56)/MS: calcd. for C 19 H 23 CIN 3 : 329.9; obsd.: 329.17 (m+1). 
     EXAMPLE 10   
     Cis-1-(2-chlorophenyl)-N 2 -(1-(R)-phenyl)-ethyl)-N 1 -methylcyclohexane-1,2-diamine (10). 
     The title compound of Example 10 was prepared according to general procedure A using (R)-α-methyl-benzylamine and ketamine. 
     LC (RT=1.05)/MS: calcd. for C 21 H 27 CIN 2 : 342.9; obsd.: 342.19 (m+1). 
     EXAMPLE 11   
     Trans-1-(2-chlorophenyl)-N 2 -(1-(S)-phenyl)-ethyl)-N 1 -methylcyclohexane-1,2-diamine (11). 
     The title compound of Example 11 was prepared according to general procedure A using (S)-α-methyl-benzylamine and ketamine. 
     LC (RT=0.81)/MS: calcd. for C 21 H 27 CIN 2 : 342.9; obsd.: 342.19 (m+1). 
     EXAMPLE 12   
     Trans-1-(2-chlorophenyl)-N 2 -(3-(1-imidazolyl)-propyl)-N 1 -methylcyclohexane-1,2-diamine (12 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -(3-(1-imidazolyl)-propyl)-N 1 -methylcyclohexane-1,2-diamine (12 b ). 
     The title compounds of Example 12 were prepared according to general procedure A using 3-(1-imidazolyl)-propylamine and ketamine. 
     a.) LC (RT=0.70)/MS: calcd. for C 19 H 27 CIN 4 : 346.9; obsd.: 346.19 (m+1). 
       1 H—nmr (DMSO—d6, 400 MHz, T=30° C.) δ 1.35-1.55 (m, 2H), 1.60-1.75 (m, 1H), 1.80-2.00 (m, 4H), 2.05-2.35 (m+s, 6H), 2.45-2.70 (m, 2H), 3.95-4.25 (m, 3H), 7.40-7.50 (m, 3H), 7.55 (m, 1H), 7.60 (m, 1H), 7.70 (s, 1H), 8.95 (s, 1H). 
     b.) LC (RT=0.54)/MS: calcd. for C 19 H 27 CIN 4 : 346.9; obsd.: 346.19 (m+1). 
       1 H—nmr (DMSO—d6, 400 MHz, T=30° C.) δ 1.25 (bs, 1H), 1.40 (bs, 1H), 1.50-1.80 (m, 4H), 1.90 (m, 1H), 2.00-2.25 (m+s, 5H), 2.55 (m, 1H), 2.70-2.95 (m, 2H), 3.90 (bs, 1H), 4.20-4.35 (m, 2H), 6.50 (bs, 2H), 7.40-7.45 (m, 2H), 7.52 (m, 1H), 7.65 (m, 1H), 7.70 (m, 1H), 7.75 (m, 1H), 9.10 (s, 1H). 
     EXAMPLE 13   
     Trans-1-(2-chlorophenyl)-N 2 -(1-ethyl-pyrrolidin-2-ylmethyl)-N 1 -methylcyclohexane-1,2-diamine (13 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -(1-ethyl-pyrrolidin-2-ylmethyl)-N 1 -methylcyclohexane-1,2-diamine (13 b ). 
     The title compounds of Example 13 were prepared according to general procedure A using N-ethyl-2-(aminomethyl)-pyrrolidine and ketamine. 
     a.) LC (RT=0.55)/MS: calcd. for C 20 H 32 CIN 3 : 349.9; obsd.: 349.23 (m+1). 
     b.) LC (RT=0.70)/MS: calcd. for C 20 H 32 CIN 3 : 349.9; obsd.: 349.23 (m+1). 
     EXAMPLE 14   
     Trans-1-(2-chlorophenyl)-N 2 -(3-(pyrrolidin-1-Apropyl)-N 1 -methylcyclohexane-1,2-diamine (14 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -(3-(pyrrolidin-1-34)propyl)-N 1 -methylcyclohexane-1,2-diamine (14 b ). 
     The title compounds of Example 14 were prepared according to general procedure A using N-(3-aminopropyl)-pyrrolidine and ketamine. 
     a.) LC (RT=0.50)/MS: calcd. for C 20 H 32 CIN 3 : 349.9; obsd.: 349.23 (m+1). 
     b.) LC (RT=0.68)/MS: calcd. for C 20 H 32 CIN 3 : 349.9; obsd.: 349.23 (m+1). 
     EXAMPLE 15   
     Trans-1-(2-chlorophenyl)-N 2 -(3-phenylpropyl)-N 1 -methylcyclohexane-1,2-diamine (15 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -(3-phenylpropyl)-N 1 -methylcyclohexane-1,2-diamine (15 b ). 
     The title compounds of Example 15 were prepared according to general procedure A using 3-aminopropylbenzene and ketamine. 
     a.) LC (RT=0.71)/MS: calcd. for C 22 H 29 CIN 2 : 356.9; obsd.: 356.19 (m+1). 
     b.) LC (RT=0.77)/MS: calcd. for C 22 H 29 CIN 2 : 356.9; obsd.: 356.19 (m+1). 
     EXAMPLE 16   
     Trans-1-(2-chlorophenyl)-N 2 -(3-(morpholin-1-Apropyl)-N 1 -methylcyclohexane-1,2-diamine (16 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -(3-(morpholin-1-Apropyl)-N 1 -methylcyclohexane-1,2-diamine (16 b ). 
     The title compounds of Example 16 were prepared according to general procedure A using N-(3-aminopropyl)-morpholine and ketamine. 
     a.) LC (RT=0.49)/MS: calcd. for C 20 H 32 CIN 3 O: 365.9; obsd.: 365.22 (m+1). 
     b.) LC (RT=0.86)/MS: calcd. for C 20 H 32 CIN 3 O: 365.9; obsd.: 365.22 (m+1). 
     EXAMPLE 17   
     Trans-1-(2-chlorophenyl)-N 2 -(3-(4-methylpiperazin-1-Apropyl)-N 1 -methylcyclohexane-1,2-diamine  (17 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -(3-(4-methylpiperazin-1-Apropyl)-N 1 -methylcyclohexane-1,2-diamine (17 b ). 
     The title compounds of Example 17 were prepared according to general procedure A using N 1 -methyl-N 2 -(3-aminopropyl)-piperazine and ketamine. 
     a.) LC (RT=0.48)/MS: calcd. for C 21 H 35 CIN 4 : 378.9; obsd.: 378.26 (m+1). 
     b.) LC (RT=0.69)/MS: calcd. for C 21 H 35 CIN 4 : 378.9; obsd.: 378.26 (m+1). 
     EXAMPLE 18 
     Trans-1-(2-chlorophenyl)-N 2 -cyclohexyl- N 1 -methylcyclohexane-1,2-diamine (18 a ), and 
     Cis-1-(2-chlorophenyl)-N 2 -cyclohexyl- N 1 -methylcyclohexane-1,2-diamine (18 b ). 
     The title compounds of Example 18 were prepared according to general procedure A using cyclohexylamine and ketamine. 
     a.) LC (RT=1.55)/MS: calcd. for C 19 H 29 CIN 2 : 320.9; obsd.: 320.19 (m+1). 
     b.) LC (RT=1.05)/MS: calcd. for C 19 H 29 CIN 2 : 320.9; obsd.: 320.19 (m+1). 
     EXAMPLE 19   
     GENERAL PROCEDURE B 
     Cis-(1R,2R)-1-(2-chlorophenyl)-N 2 -(3-phenylpropyl)-N 1 -methylcyclohexane-1,2-diamine (19 a ), and 
     Cis-(1S,2S)-1-(2-chlorophenyl)-N 2 -(3-phenylpropyl)-N 1 -methylcyclohexane-1,2-diamine (19 b ). 
     The title compound of Example 15 b  (110 mg) was purified using high pressure liquid chromatography (HPLC) under the following conditions: 
     Instrument: JASCO-SFC (SuperCritical Fluid Chromatography) Semi-Prep HPLC (JASCO Inc., Easton, Md. USA). 
     Stationary Phase: Diacel Chiralpak AS-H, 10 mm column. 
     Mobile Phase: Ethanol/CO 2 . Isocratic 5%EtOH/95%CO 2 . 
     Detection: UV detection at 220, 254 nM. 
     Column Temp.: 25 ° C. 
     Flow Rate: 2.5 mL/min 
     Fraction 1 (19 a ): 35 mg. RT=7.187 min, ee&gt;99%, purity&gt;98%. 
     Fraction 2 (19 b ): 30 mg. RT=8.347 min, ee&gt;99%, purity&gt;95%. Mass Spectrum: (ESI + scan)  357.2 (M 35Cl +H) + , 359 (M 37Cl +H) + . 
     EXAMPLE 20   
     Cis-(1R,2R)-1-(2-chlorophenyl)-N 2 -(3-(morpholin-1-yl)propyl)-N 1 -methylcyclohexane-1,2-diamine (20 a ), and 
     Cis-(1S,2S)-1-(2-chlorophenyl)-N 2 -(3-(morpholin-1-yl)propyl)-N 1 -methylcyclohexane-1,2-diamine (20 b ). 
     The title compound of Example 16 b  (60 mg) was purified using high pressure liquid chromatography (HPLC) under the conditions described in Example 19 above. 
     Fraction 1 (20 a ): 17 mg. RT=10.192 min, ee&gt;99%, purity&gt;99%. Mass Spec (ESI+, Acquisition Time=2.546 min): m/z=366.23 (100%, (M+H) + ), 368 (33%, (M+H) +  for Cl 37 ) 
     Fraction 2 (20 b ): 18 mg. RT=12.783 min, ee&gt;99%, purity &gt;99%. Mass Spec (ESI+, Acquisition Time=2.548 min): m/z =366.23 (100%, (M+H) + ), 368 (33%, (M+H) +  for Cl 37 ). 
     DETERMINATION OF PHARMACOLOGICAL ACTIVITY 
     The compounds from the above Examples were tested for activity vs. kappa opioid receptors (KOR) and for Sigma-1 activity. Ki determinations were generously provided by the National Institute of Mental Health&#39;s Psychoactive Drug Screening Program (PDSP), Contract # HHSN-271-2013-00017-C (NIMH PDSP). The NIMH PDSP is Directed by Bryan L. Roth MD, PhD at the University of North Carolina at Chapel Hill and Project Officer Jamie Driscoll at NIMH, Bethesda Md. U.S.A. Procedures employed by the PDSP are described in the NIMH PDSP Assay Protocol Book, Version II. 
     
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                   
               
               
                 Data 
               
             
          
           
               
                   
                   
                 KOR 
                 Sigma-1 
               
               
                   
                 Example 
                 Ki (nM) 
                 KI (nM) 
               
               
                   
                   
               
             
          
           
               
                   
                 12b 
                 &gt;1000 nM 
                 231 
               
               
                   
                 15a 
                   526 nM 
                 2260 
               
               
                   
                 15b 
                   139 nM 
                 177 
               
               
                   
                 16b 
                   798 nM 
                 17 
               
               
                   
                 17a 
                 &gt;1000 nM 
                 19 
               
               
                   
                 17b 
                 &gt;1000 nM 
                 72 
               
               
                   
                 18b 
                   608 nM 
                 n.d. 
               
               
                   
                   
               
               
                   
                 n.d. - not determined