N-LINKED SULFONAMIDES OF HETEROCYCLIC THIOESTERS

Abstract: This invention relates to neurotrophic low molecular weight, small molecule N-linked sulfonamides of heterocyclic thioesters having an affinity for FKBP-type immunophilins, and their use as inhibitors of the enzyme activity associated with immunophilin proteins, particularly peptidyl-prolyl isomerase, or rotamase, enzyme activity.

Description: N-LINKED SULFONAMIDES OF HETEROCYCLIC THIOESTERS This is a continuation-in-part application of U.S. Patent Application Serial No. 08/775,584 filed December 31, 1996. BACKGROUND OF THE INVENTION 1. Field of Invention This invention relates to neurotrophic low molecular weight, small molecule N-lin ed sulfonamides of heterocyclic thioesters having an affinity for FKBP-type immunophilins and their use as inhibitors of the enzyme activity associated with immunophilin proteins, particularly peptidyl-prolyl isomerase, or rotamase, enzyme activity. 2. Description of Related Art The term immunophilin refers to a number of proteins that serve as receptors for the principal immunosuppressant drugs, Cyclosporin A (CsA) , FK506, and rapamycin. Known classes of immunophilins are cyclophilins and FK506 binding proteins, or FKBPs . Cyclosporin A binds to cyclophilin A while FK506 and rapamycin bind to FKBP12. These immunophilin-drug complexes interface with various intracellular signal transduction systems, especially the immune and nervous systems. Immunophilins are known to have peptidyl-prolyl isomerase (PPIase) , -or rotamase, enzyme activity. It has been determined that rotamase enzyme activity plays a role in the catalyzation of the interconversion of the els and trans isomers of peptide and protein substrates for the immunophilin proteins. Immunophilins were originally discovered and studied in the immune tissue. It was initially postulated by those skilled in the art that inhibition of the immunophilins' rotamase activity leads to inhibition of T-cell proliferation, thereby causing the immunosuppressive activity exhibited by immunosuppressant drugs, such as cyclosporin A, FK506 and rapamycin. Further study has shown that the inhibition of rotamase activity, in and of itself, does not result in immunosuppressive activity. Schreiber et al . , Sci ence, 1990, vol. 250, pp. 556- 559. Instead, immunosuppression appears to stem from the formulation of a complex of immunosuppressant drugs and immunophilins. It has been shown that the immunophilin-drug complexes interact with ternary protein targets as their mode of action. Schreiber et al., Cell, 1991, vol. 66, pp. 807-815. In the case of FKBP-FK506 and cyclophilin-CsA, the immunophilin-drug complexes bind to the enzyme calcineurin and inhibit the T-cell receptor signalling which leads to T-cell proliferation. Similarly, the immunophilin-drug complex of FKBP-rapamycin interacts with the RAFTl/FRAP protein and inhibits the IL-2 receptor signalling. Immunophilins have been found to be present at high concentrations in the central nervous system. Immunophilins are enriched 10-50 times more in the central nervous system than in the immune system. Within neural tissues, immunophilins appear to influence nitric oxide synthesis, neurotransmitter release and neuronal process extension. It has been found that picomolar concentrations of an immunosuppressant such as FK506 and rapamycin stimulate neurite outgrowth in PC12 cells and sensory neurons, namely dorsal root ganglion cells (DRGs). Lyons et al . , Proc . of Na tl . Acad . Sci . , 1994, vol. 91, pp. 3191-3195. In whole animal experiments, FK506 has been shown to stimulate nerve regeneration following facial nerve injury. Surprisingly, it has been found that certain compounds with a high affinity for FKBPs are potent rotamase inhibitors and exhibit excellent neurotrophic effects. Furthermore, these rotamase inhibitors are devoid of immunosuppressive activity. These findings suggest the use of rotamase inhibitors in treating various peripheral neuropathies and enhancing neuronal regrowth in the central nervous system (CNS) . Studies have demonstrated that neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS) may occur due to the loss of, or decreased availability of, a neurotrophic substance specific for a particular population of neurons affected in the disorder. Several neurotrophic factors affecting specific neuronal populations in the central nervous system have been identified. For example, it has been hypothesized that Alzheimer's disease results from a decrease or loss of nerve growth factor (NGF) . It has thus been proposed to treat Senile Dementia Alzheimer's Type (SDAT) patients with exogenous nerve growth factor or other neurotrophic proteins, such as brain derived growth factor, glial derived growth factor, ciliary neurotrophic factor and neurotropin-3, to increase the survival of degenerating neuronal populations . Clinical application of these proteins in various neurological disease states is hampered by difficulties in the delivery and bioavailability of large proteins to nervous system targets. By contrast, immunosuppressant drugs with neurotrophic activity are relatively small and display excellent bioavailability and specificity. However, when administered chronically, immunosuppressant drugs exhibit a number of potentially serious side effects including nephrotoxicity, such as impairment of glomerular filtration and irreversible interstitial fibrosis (Kopp et al . , J. Am. Soc . Nephrol . , 1991, 1:162); neurological deficits, such as involuntary tremors, or non-specific cerebral angina, such as non- localized headaches (De Groen et al., N. Engl . J. Med. , 1987, 317:861); and vascular hypertension with complications resulting therefrom (Kahan et al . , N. Engl . J. Med. , 1989, 321:1725). In order to prevent the side effects associated with use of the immunosuppressant compounds, the present invention provides non-immunosuppressive compounds containing small molecule FKBP rotamase inhibitors for enhancing neurite outgrowth, and promoting neuronal growth and regeneration in various neuropathological situations where neuronal repair can be facilitated, including: peripheral nerve damage caused by physical injury or disease state such as diabetes; physical damage to the central nervous system (spinal cord and brain); brain damage associated with stroke; and neurological disorders relating to neurodegeneration, such as Parkinson's disease, SDAT (Alzheimer's disease), and amyotrophic lateral sclerosis. SUMMARY OF THE INVENTION The present invention relates to neurotrophic low molecular weight, small molecule compounds having an affinity for FKBP-type immunophilins. Once bound to these proteins, the neurotrophic compounds are potent inhibitors of the enzyme activity associated with immunophilin proteins, particularly peptidyl-prolyl isomerase, or rotamase, enzyme activity. A key feature of the compounds of the present invention is that they do not exert any significant immunosuppressive activity in addition to their neurotrophic activity. Another significant feature is the novel addition of a thioester linkage showing unexpected increase in bioavailability and potency. Specifically, the present invention relates to a compound of formula I: or a pharmaceutically acceptable salt, ester, or solvate thereof, wherein: A and B are taken together, with the nitrogen and carbon atoms to which they are respectively attached, to form a 5-7 membered saturated or unsaturated heterocyclic ring containing any combination of CH 2 , 0, S, SO, S0 2 , NH or NR 2 ; X is either 0 or S; Y is a direct bond to Z, a Cj . -Cg straight or branched chain alkyl, or a C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R, is selected from the group consisting of hydrogen, (C 1 -C 6 ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; Z is a direct bond, or a ^- straight or branched chain alkyl, or a C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are- optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R 2 is selected from the group consisting of hydrogen, (Cπ-Cg) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR,_ and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; C and D are independently: hydrogen, Ar, -Cg straight or branched chain alkyl, or C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more position (s) with C 3 -C 8 cycloalkyl, C 5 -C 7 cycloalkenyl, hydroxyl, carbonyl oxygen, or Ar, wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl groups are optionally substituted with Cj-Cg alkyl, C 2 -C 6 alkenyl, hydroxy, amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, - alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R, is selected from the group consisting of hydrogen, -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (Ci-C bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR : and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; wherein Ar is an aryl or heteroaryl moiety which is substituted or unsubstituted; and R : is selected from the group consisting of Ar, C 3 -C e cycloalkyl, C^Cg straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, or C- C 6 straight or branched chain alkyl or C 2 -C 6 straight or branched chain alkenyl which is substituted in one or more positions with Ar, amino, halo, haloalkyl, hydroxy, trifluoromethyl, Ci-Cg straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, carbonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, substituted alkyl or alkenyl wherein any of the carbon atoms of the alkyl or alkenyl are optionally replaced with S, SO, S0 2 , 0, or NR 2 wherein R 2 is selected from the group consisting of hydrogen, (Ci-C -straight or branched chain alkyl, (C 3 -C 3 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR-, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group or C 3 -C 8 cycloalkyl . In preferred embodiments, Ar is a cyclic or fused cyclic ring and includes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to five position (s) with halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, C j -Cg straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, Cη-C 6 alkoxy, C 2 -C 6 alkenyloxy, phenoxy, benzyloxy, amino, thiocarbonyl, ester, thioester, cyano, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-8 members; wherein the heterocyclic ring contains 1-4 heteroatom(s) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a corresponding N-oxide. Particularly preferred Ar groups include phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, furyl, thiophenyl, i idazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl. A preferred embodiment of this invention is a compound of formula II: or a pharmaceutically acceptable salt, ester, or solvate thereof, wherein: E, F, G and H are independently CH,, 0, S, SO, S0 2 , NH or NR, wherein at least two of E, F, G, and H are CH, ; X is either 0 or S; Y is a direct bond to Z, a Ci-Cg straight or branched chain alkyl, or a C,-C straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R, is selected from the group consisting of hydrogen, -straight or branched chain alkyl, (C 3 -C 3 ) -straight or branched chain alkenyl or alkynyl, and (C^C,) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; Z is a direct bond, or a C : -C 6 straight or branched chain alkyl, or a C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR,, S, SO, or S0, wherein R 2 is selected from the group consisting of hydrogen, (C : -Cg) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of R X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; C and D are independently: hydrogen, Ar, C^ straight or branched chain alkyl, or C-C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more position (s) with C 3 -C 9 cycloalkyl, C 5 -C 7 cycloalkenyl, hydroxyl, carbonyl oxygen, or Ar, wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl groups are optionally substituted with C 1 -C 6 alkyl, C,-C 6 alkenyl, hydroxy, amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or SO,, wherein R, is selected from the group consisting of hydrogen, (C^Cg) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR α and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; wherein Ar is an aryl or heteroaryl moiety which is substituted or unsubstituted; and R-, is selected from the group consisting of Ar, C 3 -C 8 cycloalkyl, Ci-Cg straight or branched chain alkyl, C,-C 6 straight or branched chain alkenyl, or C-_- C 6 straight or branched chain alkyl or C 2 -C 6 straight or branched chain alkenyl which is substituted in one or more positions with Ar, amino, halo, haloalkyl, hydroxy, trifluoromethyl, C-,-C 6 straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, carbonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, substituted alkyl or alkenyl wherein any of the carbon atoms of the alkyl or alkenyl are optionally replaced with S, SO, SO,, 0, or NR, wherein R 2 is selected from the group consisting of hydrogen, (C α -C 6 ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C J. -C,) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group or C 3 -C 8 cycloalkyl. In preferred embodiments, Ar is a cyclic or fused cyclic ring and includes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to five position (s) with halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, C x -C 6 straight or branched chain alkyl, C,-C 6 straight or branched chain alkenyl, C 1 -C 6 alkoxy, C,-C 6 alkenyloxy, phenoxy, benzyloxy, amino, thiocarbonyl, ester, thioester, cyano, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-8 members; wherein the heterocyclic ring contains 1-4 heteroatom(s) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a corresponding N-oxide. Particularly preferred Ar groups include phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, furyl, thiophenyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl. Another preferred embodiment is a compound of formula III or a pharmaceutically acceptable salt, ester, or solvate thereof, wherein: E, F, and G are independently CH 2 , 0, S, SO, S0 2 , NH or NR 2 wherein at least 2 of E, F, and G are CH,; X is either 0 or S;' Y is a direct bond to Z, a C^Cg straight cr branched chain alkyl, or a C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR,, S, SO, or SO,, wherein R 2 is selected from the group consisting of hydrogen, (Cη-C 6 ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 3. -C bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; Z is a direct bond, or a C : -C 6 straight or branched chain alkyl, or a C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or SO,, wherein R 2 is selected from the group consisting of hydrogen, (Ci-Cg) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; C and D are independently: hydrogen, Ar, Ci-Cg straight or branched chain alkyl, or C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more position (s) with C 3 -C 8 cycloalkyl, C 5 -C 7 cycloalkenyl, hydroxyl, carbonyl oxygen, or Ar, wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl groups are optionally substituted with alkyl, C 2 -C b alkenyl, hydroxy, amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR, S, SO, or SO,, wherein R, is selected from the group consisting of hydrogen, (C : -C b ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (Cι-C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR-, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; wherein Ar is an aryl or heteroaryl moiety which is substituted or unsubstituted; and Rj_ is selected from the group consisting of Ar, C 3 -C 8 cycloalkyl, C^Cg straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, or C l - C 6 straight or branched chain alkyl or C 2 -C 6 straight or branched chain alkenyl which is substituted in one or more positions with Ar, amino, halo, haloalkyl, hydroxy, trifluoromethyl, straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, carbonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, substituted alkyl or alkenyl wherein any of the carbon atoms of the alkyl or alkenyl are optionally replaced with S, SO, SO,, 0, or NR, wherein R, is selected from the group consisting of hydrogen, (C 1 -C 6 ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group or C 3 -C 8 cycloalkyl . In preferred embodiments, Ar is a cyclic or fused cyclic ring and includes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to five position (s) with halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, C x -Cg straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, Cx-C 8 alkoxy, C 2 -C 3 alkenyloxy, phenoxy, benzyloxy, amino, thiocarbonyl, ester, thioester, cyano, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-8 members; wherein the heterocyclic ring contains 1-4 heteroatom(s) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a corresponding N-oxide. Particularly preferred Ar groups include phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, furyl, thiophenyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl. A further particularly preferred embodiment of this invention is a compound of formula IV: or a pharmaceutically acceptable salt, ester, or solvate thereof, wherein: n is 1, 2 or 3 forming a 5-7 member heterocyclic ring; X is either 0 or S; Y is a direct bond to Z, a C x -C 6 straight or branched chain alkyl, or a C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR,, S, SO, or SO,, wherein R, is selected from the group consisting of hydrogen, [ C x -C 3 ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C^C,,) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR : and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; Z is a direct bond, or a C : -C, straight or branched chain alkyl, or a C,-C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R, is selected from the group consisting of hydrogen, -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR : and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; C and D are independently: hydrogen, Ar, C^Cg straight or branched chain alkyl, or C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more position (s) with C 2 -C 8 cycloalkyl, C 5 -C^ cycloalkenyl, hydroxyl, carbonyl oxygen, or Ar, wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl groups are optionally substituted with C^Cg alkyl, C 2 -C 6 alkenyl, hydroxy, amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R 2 is selected from the group consisting of hydrogen, {C -C 6 ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; wherein Ar is an aryl or heteroaryl moiety which is substituted or unsubstituted; and R x is selected from the group consisting of Ar, C 3 -C 8 cycloalkyl, Ci-Cg straight or branched chain alkyl, C,-C 6 straight or branched chain alkenyl, or C l - C 6 straight or branched chain alkyl or C,-C 3 straight or branched chain alkenyl which is substituted in one or more positions with Ar, amino, halo, haloalkyl, hydroxy, trifluoromethyl, straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, carbonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, substituted alkyl or alkenyl wherein any of the carbon atoms of the alkyl or alkenyl are optionally replaced with S, SO, S0 2 , 0, or NR, wherein R 2 is selected from the group consisting of hydrogen, (Cx-Cg) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group or C 3 -C 8 cycloalkyl. In preferred embodiments, Ar is a cyclic or fused cyclic ring and includes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to five position (s) with halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, Cι-C 6 straight or branched chain alkyl, C,-C 6 straight or branched chain alkenyl, Ci-Cg alkoxy, C 2 -C 6 alkenyloxy, phenoxy, benzyloxy, amino, thiocarbonyl, ester, thioester, cyano, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-8 members; wherein the heterocyclic ring contains 1-4 heteroatom(s) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a corresponding N-oxide. Particularly preferred Ar groups include phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, furyl, thiophenyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl. Particularly preferred compounds of the present invention are selected from the group consisting of: 3- ( 4-Methoxyphenyl ) propyl ( 2 S ) - 1 - (phenylsulfonyl) -2-pyrrolidinecarbothioate (4) ; 3- ( 4-Methoxyphenyl) propyl ( 2 S ) - 1 - (benzylsulf onyl) -2-pyrrolidinecarbothioate (5); 3- (4-Methoxyphenyl)propyl ( 2S ) -1- [ ( 4- methylphenyl) sulfonyl] -2-pyrrolidinecarbothioate (6) ; (2, 2-methylphenyl) ethyl (2S) -1- [ (4-ethylphenyi) sulfonyl] -2-pyrrolidinecarbothioate (21) ; 3-Phenylpropyl ( 2S ) -1- (phenylsulfonyl ) -2- pyrrolidinecarbothioate (22) ; 3-Phenylpropyl (2S) -1- (benzylsulf onyl) -2- pyrrolidinecarbothioate (23) ; 3- (1-Naphthyl) propyl (2S) -1- (benzylsulfonyl) -2- pyrrolidinecarbothioate (24) ; 3-Phenylpropyl J2S) -1- [ ( 4-ethylphenyl) sulfonyl] - 2-pyrrolidinecarbothioate (25) ; 3- (4-Methoxyphenyl)propyl 1 - [ ( 4 - methylphenyl ) sulfonyl] -2-piperidinecarbothioate (26) ; 3- (4-Methoxyphenyl) propyl 1- (benzylsulfonyl) -2- piperidinecarbothioate (27) ; 3- (4-Methoxyphenyl) propyl 1- (phenylsulfonyl) -2- piperidinecarbothioate (28); 3- [4- (Tri luoromethyl) phenyl] propyl 1- [ (4- methylphenyl) sulfonyl] -2-piperidinecarbothioate (29) ; and a pharmaceutically acceptable salt, ester, or solvate, hydrate, or a mixture thereof (numbers in parentheses indicate compound numbers; See also Table I and Examples) . The present invention further relates to a method of effecting a neuronal activity in an animal, comprising: administering to the animal a neurotrophically effective amount of the compound of formula I, II, III or IV. The present invention further relates to the use of any of the compounds of Formula I, II, III, IV or in Table I below in the preparation of a medicament for the treatment of a disease such as peripheral neuropathy caused by physical injury or disease state, physical damage to the brain, physical damage to the spinal cord, stroke , associated with brain damage, Alzheimer's Disease, Parkinson's Disease, and amyotrophic lateral sclerosis. The present invention also contemplates processes for manufacturing the novel compounds, particularly the processes delineated in Schemes A, B, C, and D. DETAILED DESCRIPTION OF THE INVENTION Definitions "Alkyl" means a branched or unbranched saturated hydrocarbon chain comprising a designated number of carbon atoms. For example, C 1 -C 6 straight or branched alkyl hydrocarbon chain contains 1 to 6 carbon atoms, and includes but is not limited to substituents such as methyl, ethyl, propyl, iso-propyl, butyl, ISO- butyl, tert-butyl, n-pentyl, n-hexyl, and the like, unless otherwise indicated. "Alkenyl" means a branched or unbranched unsaturated hydrocarbon chain comprising a designated number of carbon atoms. For example, C,-C 3 straight or branched alkenyl hydrocarbon chain contains 2 to 6 carbon atoms having at least one double bond, and includes but is not limited to substituents such as ethenyl, propenyl, iso-propenyl, butenyl, iso-butenyl, tert-butenyl, n-pentenyl, n-hexenyl, and the like, unless otherwise indicated. "Alkoxy" means -the group -OR wherein R is alkyl as herein defined. Preferably, R is a branched or unbranched saturated hydrocarbon chain containing 1 to 6 carbon atoms . "Ar" means an aryl or heteroaryl moiety which is substituted or unsubstituted, especially a cyclic or fused cyclic ring and includes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to five position (s) with halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, C,-C 6 straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, Ci-Cg alkoxy, C 2 -C 6 alkenyl xy, phenoxy, benzyloxy, amino, thiocarbonyl, ester, thioester, cyano, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-8 members; wherein the heterocyclic ring contains 1-4 heteroatom (s) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a corresponding N-oxide . Particularly preferred aryl or heteroaryl moieties include but are not limited to phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, furyl, thiophenyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl . "Halo" means at least one fluoro, chloro, bro o, or iodo moiety, unless otherwise indicated. "Phenyl" includes all possible isomeric phenyl radicals, optionally monosubstituted or multi-substituted with substituents selected from the group consisting of amino, halo, haloalkyl, hydroxy, trifluoromethyl, C x -C 6 straight or branched chain alkyl, C,-C 6 straight or branched chain alkenyl, carbonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, NR 2 wherein R 2 is selected from the group consisting of hydrogen, (C x - C 6 ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C x -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR x and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group. The term "pharmaceutically acceptable salt, ester, or solvate" refers to salt, ester, or solvates of the subject compounds which possess the desired pharmacological activity and which are neither biologically nor otherwise undesirable. The salt, ester, or solvates can be formed with inorganic acids such as acetate, adipate, alginate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, citrate, camphorate, campho r sul f ona t e , cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptanoate, gluconate, glycerophosphate, hemisulfate, heptanoate, hexanoate, hydrochloride hydrobromide, hydroiodide, 2- hydroxyethanesulfonate, lactate, maleate, methanesulfonate, naphthylate, 2-naphthalenesulfonate, nicotinate, oxalate, sulfate, thiocyanate, tosylate and undecanoate. Base salt, ester, or solvates include ammonium salts, alkali metal salts such as sodium and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salt with organic bases such as dicyclohexylamine salts, N-methyl-D- glucamine, and salts with amino acids such as arginine, lysine, and so forth. Also, the basic nitrogen-containing groups can be quarternized with such agents as lower alkyl halides, such as methyl, ethyl, propyl, and butyl chloride, bromides and iodides; dialkyl sulfates like dimethyl, diethyl, dibutyl and diamyl sulfates, long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides, aralkyl halides like benzyl and phenethyl bromides and others. Water or oil-soluble or dispersible products are thereby obtained. The compounds of this invention may possess at least one asymmetric center and thus can be produced as mixtures of stereoisomers or as individual enantiomers or diastereomers . The individual stereoisomers may be obtained by using an optically active starting material, by resolving a racemic or non-racemic mixture of an intermediate at some appropriate stage of the synthesis, or by resolution of the compound of formula (I) . It is understood that the individual stereoisomers as well as mixtures (racemic and non-racemic) of stereoisomers are encom- passed by the scope of the present invention. The S- stereoisomer at atom 1 of formula I is most preferred due to its greater activity. "Isomers" are different compounds that have the same molecular formula and includes cyclic isomers such as (iso) indole and other isomeric forms of cyclic moieties . "Stereoisomers" are isomers that differ only in the way the atoms are arranged in space. "Enantiomers" are a pair of stereoisomers that are non-superimposable mirror images of each other. "Diastereoisomers" are stereoisomers which are not mirror images of each other. "Racemic mixture" means a mixture containing equal parts of individual enantiomers. "Non-racemic mixture" is a mixture containing unequal parts of individual enantiomers or stereoisomers. The term "preventing neurodegeneration" as used herein includes ' the ability to prevent neurodegeneration in patients newly diagnosed as having a neurodegenerative disease, or at risk of developing a new degenerative disease and for preventing further neurodegeneration in patients who are already suffering from or have symptoms of a neurodegenerative disease. The term "treatment" as used herein covers any treatment of a disease and/or condition in an animal, particularly a human, and includes: (i) preventing a disease and/or condition from occurring in a subject which may be predisposed to the disease and/or condition but has not yet been diag- nosed as having it; (ii) inhibiting the disease and/or condition, i.e., arresting its development; or (iii) relieving the disease and/or condition, i.e., causing regression of the disease and/or condi- tion. The system used in naming the compounds of the present invention is shown below, using a compound of formula IV as an example. A compound of the present invention, especially Formula IV, wherein n is 1, X is 0, Y is (CH,),, Z is CH, C is p-Methoxyphenyl, D is H and R x is Phenyl, is named 3 - ( 4 -Me thoxyphenyl ) propyl (2S)-1- (phenylsulfonyl) -2-pyrrolidinecarbothioate . Compounds of the Invention The neurotrophic low molecular weight, small molecule FKBP inhibitor compounds of this invention have an affinity for FKBP-type immunophilins, such as FKBP12. When the neurotrophic compounds of this invention are bound to an FKBP-type immunophilin, they have been found to inhibit the prolyl-peptidyl cis - trans isomerase activity, or rotamase, activity of the binding protein and unexpectedly stimulate neurite growth. Specific exemplifications of these embodiments are presented in TABLE I, below. TABLE I No. n X Y Z C D Rl 1 1 0 CH 2 CH Phenyl H Phenyl 2 1 0 CH, CH Phenyl H α-Methylphenyl 3 1 0 CH, CH Phenyl H 4-Methylphenyl 4 1 0 (CH 2 ), CH p-Methoxyphenyl H Phenyl 5 l' 0 (CH 2 ) 2 CH p-Methoxyphenyl H α-Methylphenyl 6 1 0 (CH 2 ) 2 CH p-Methoxyphenyl H 4-Methylphenyl t X 1 0 (CH,) 2 CH Phenyl Phenyl Phenyl 8 1 0 (CH,) 2 CH Phenyl Phenyl α-Methylphenyl 9 1 0 (CH,), CH Phenyl Phenyl 4-Methylphenyl 10 2 0 (CH 2 ) 3 CH Phenyl H Phenyl 11 2 0 (CH,) . CH Phenyl H α-Methylphenyl 12 2 0 (CH,) 3 CH Phenyl H 4-Methylphenyl 13 2 0 (CH,), CH Phenyl H 3, 4, 5-trimethoxyphenyl 14 2 0 (CH 2 ), CH Phenyl H Cyclohexyl 15 2 0 Direct CH 3-Phenylpropyl 3- -Phenylp.tropyl Phenyl 16 2 0 Direct CH 3-Phenylpropyl 3- -Phenylp.copyl α-Methylphenyl 17 2 0 Direct CH 3-Phenylpropyl 3- -Phenylp]copy! -Methylphenyl 18 2 0 Direct CH 3-Phenylethyl 3- -Phenylethyl 4-Methylphenyl 19 2 0 Direct CH 3- (4-Methoxyphenyl) propyl 3- -Phenylp:copyl 4-Methylphenyl 20 2 0 Direct CH 3- (2-Pyridyl) propyl 3- Phenylpicopyl 4-Methylphenyl 'lieny 1 4-Ethylplienyl Phenyl α-Me yl phenyl α-Met hylphenyl 4-Ethylphenyl 4-Methylphenyl α-Methylphenyl Phenyl t y I ) 4-Methylphenyl The compounds of the present invention may exist as stereoisomeric forms, either enantiomers or diastereoisomers . Included within the scope of the invention are the enantiomers, the racemic form, and diastereoisomeric mixtures. Enantiomers and diastereoisomers can be separated by methods known to those skilled in the art. Methods of Using the Compounds of the Invention The compounds of the present invention have an affinity for the FK506 binding protein, particularly FKBP12, which is present in the neuronal tissue. When the inventive compounds bind to FKBP in neuronal tissue, they exhibit excellent neurotrophic activity. This activity is useful in the stimulation of damaged neurons, the promotion of neuronal regeneration, the prevention of neurodegeneration, and the treatment of several neurological disorders known to be associated with neuronal degeneration and peripheral neuropathies. For the foregoing reasons, the present invention further relates to a method of effecting a neuronal activity in an animal, comprising: administering to the animal a neurotrophically effective amount of a compound of formula I, II, III or IV. In a preferred embodiment, the neuronal activity is selected from the group consisting of stimulation of the growth of damaged neurons, promotion of neuronal regeneration, prevention of neurodegeneration and treatment of a neurological disorder. The compounds of the present invention are particularly useful for preventing neurodegeneration in patients suffering from a neurodegenerative disease or who have symptoms of a neurodegenerative disease. The compounds are also useful for preventing neurodegeneration in patients newly diagnosed as having a neurodegenerative disease or at risk for developing a neurodegenerative disease. These compounds are also useful for, but not limited to, preventing neurodegeneration in patients suffering from Parkinson's disease or having symptoms of Parkinson's disease. These treatment methods are exemplified in the MPTP model and data described herein. The neurological disorders that may be treated include but are not limited to: trigeminal neuralgia; glossopharyngeal neuralgia; Bell's Palsy; yasthenia gravis; muscular dystrophy; amyotrophic lateral sclerosis; progressive muscular atrophy; progressive bulbar inherited muscular atrophy; herniated; ruptured or prolapsed invertebrate disk syndromes; cervical spondylosis; plexus disorders; thoracic outlet destruction syndromes; peripheral neuropathic such as those caused by lead, dapsone, ticks, porphyria, or Guillain-Barre syndrome; Alzheimer's disease; and Parkinson's disease. The compounds of the present invention are particularly useful for treating a neurological disorder selected from the group consisting of: peripheral neuropathy caused by physical injury or disease state, physical damage to the brain, physical damage to the spinal cord, stroke associated with brain damage, and neurological disorder relating to neurodegeneration. Examples of neurological disorders relating to neurodegeneration are Alzheimer's Disease, Parkinson's Disease, and amyotrophic lateral sclerosis . Pharmaceutical Compositions of the Invention The present invention also relates to a pharmaceutical composition comprising: (i) a neurotrophically effective amount of the compound of formula I, II, III or IV, and (ii) a pharmaceutically acceptable carrier. The above discussion relating to the utility and administration of the compounds of the present invention also applies to the pharmaceutical compositions of the ^ present invention. The term "pharmaceutically acceptable carrier" as used herein refers to any carrier, diluent, excipient, suspending agent, lubricating agent, adjuvant, vehicle, delivery system, emulsifier, disintegrant, absorbant, preservative, surfactant, colorant, flavorant, or sweetener. For these purposes the compounds of the present invention may be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir in dosage formulations containing conventional non-toxic pharmaceutically-acceptable carriers, adjuvants and vehicles. The term parenteral as used herein includes subcutaneous, intravenous, intramuscular, intraperitoneally, intrathecally, intraventricularly, intrasternal and intracranial injection or infusion techniques . For oral administration, the compounds of the present invention may be provided in any suitable dosage form known in the art. For example, the compositions may be incorporated into tablets, powders, granules, beads, chewable lozenges, capsules, liquids, aqueous suspensions or solutions, or similar dosage forms, using conventional equipment and techniques known in the art. Tablet dosage forms are preferred. Tablets may contain carriers such as lactose and corn starch, and/or lubricating agents such as magnesium stearate. Capsules may contain diluents including lactose and dried corn starch. Aqueous suspensions may contain emulsifying and suspending agents combined with the active ingredient. When preparing dosage form incorporating the compositions of the invention, the compounds may also be blended with conventional excipients such as binders, including gelatin, pregelatinized starch, and the like; lubricants, such as hydrogenated vegetable oil, stearic acid, and the like; diluents, such as lactose, mannose, and sucrose; disintegrants, such as carboxymethylcellulose and sodium starch glycolate; suspending agents, such as povidone, polyvinyl alcohol, and the like; absorbants, such as silicon dioxide; preservatives, such as methylparaben, propylparaben, and sodium benzoate; surfactants, such as sodium lauryl sulfate, polysorbate 80, and the like; colorants such as F.D.& C. dyes and lakes; flavorants; and sweeteners. Compositions and methods of the invention also may utilize controlled release technology. Thus, for example, the inventive compounds may be incorporated into a hydrophobic polymer matrix for controlled release over a period of days. Such controlled release films are well known to the art. Particularly preferred are transdermal delivery systems. Other examples of polymers commonly employed for this purpose that may be used in the present invention include nondegradable ethylene-vinyl acetate copolymer and degradable lactic acid-glycolic acid copolymers which may be used externally or internally. Certain hydrogels such as poly (hydroxyethylmethacrylate) or poly (vinylalcohol) also may be useful, but for shorter release cycles then the other polymer releases systems, such as those mentioned above. To be effective therapeutically as central nervous system targets, the compounds of the present invention should readily penetrate the blood-brain barrier when peripherally administered. Compounds which cannot penetrate the blood-brain barrier can be effectively administered by an intraventricular route or other appropriate delivery system suitable for administration to the brain. The compounds of the present invention may be administered in the form of sterile injectable preparations, for example, as sterile injectable aqueous or oleaginous suspensions. These suspensions may be formulated according to techniques known in the art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparations may also be sterile injectable solutions or suspensions in non-toxic parenterally-acceptable diluents or solvents, for example, as solutions in 1, 3-butanediol . Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as solvents or suspending mediums. For this purpose, any bland fixed oil may be employed including synthetic mono- or di-glycerides . Fatty acids such as oleic acid and its glyceride derivatives, including olive oil and castor oil, especially in their polyoxyethylated versions, are useful in the preparation of injectables. These oil solutions or suspensions may also contain long-chain alcohol diluents or dispersants. The compounds of this invention may also be administered rectally in the form of suppositories. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient which is solid at room temperature, but liquid at rectal temperature and, therefore, will melt m the rectum to release the drug. Such materials include cocoa butter, beeswax and polyethylene glycols. The compounds of this invention may also be administered topically, especially when the conditions addressed for treatment involve areas or organs readily accessible by topical application, including neurological disorders of the eye, the skin, or the lower intestinal tract. Suitable topical formulations are readily prepared for each of these areas. For topical application to the eye, or ophthalmic use, the compounds can be formulated as micronized suspensions in isotonic, pH adjusted sterile saline, or, preferably, as solutions in isotonic, pH adjusted sterile saline, either with or without a preservative such as benzylalkonium chloride. Alternatively for the ophthalmic uses the compounds may be formulated in an ointment such as petrolatum. For topical application to the skin, the compounds can be formulated in a suitable ointment containing the compound suspended or dissolved in, for example, a mixture with one or more of the following: mineral oil, liquid petrolatum, white petrolatum, propylene glycol, polyoxyethylene polyoxypropylene compound, emulsifying wax and water. Alternatively, the compounds can be formulated in a suitable lotion or cream containing the active compound suspended or dissolved in, for example, a mixture of one or more of the following: mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol, 2- octyldodecanol, benzyl alcohol and water. Topical application for the lower intestinal tract an be effected in a rectal suppository formulation (see above) or in a suitable enema formulation. Dosage levels on the order of about 0.1 mg to about 10,000 mg of the active ingredient compound are useful in the treatment of the above conditions, with preferred levels of about 0.1 mg to about 1,000 mg. The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. It is understood, however, that a specific dose level for any particular patient will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, rate of excretion, drug combination, and the severity of the particular disease being treated and form of administration. The compounds can be administered with other neurotrophic agents such as neurotrophic growth factor (NGF) , glial derived growth factor, brain derived growth factor, ciliary neurotrophic factor, and neurotropin-3. The dosage level of other neurotrophic drugs will depend upon the factors previously stated and the neurotrophic effectiveness of the drug combination. The present invention relates to the use of any of the compounds seen in Table I in the preparation of a medicament for the treatment of a disease such as peripheral neuropathy caused by physical injury or disease state, physical damage to the brain, physical damage to the spinal cord, stroke associated with brain damage, Alzheimer's Disease, Parkinson's Disease, and amyotrophic lateral sclerosis. The present invention also contemplates processes for manufacturing the novel compounds, particularly the processes delineated in schemes A and B. Methods of Making the Compounds of the Invention The novel compounds of this invention may be readily prepared by standard techniques of organic chemistry, utilizing the general synthetic pathway depicted below. As described by Scheme A, cyclic amino acids 1 protected by suitable blocking groups P on the amino acid nitrogen may be reacted with thiols RSH to generate thioesters 2. After removal of the protecting group, the free a ine 3 may be reacted with various sulfonyl chlorides 4 to provide final products 5 in good to excellent yield. R-SH Deprotect »- Coupling Method 2 SCHEME A P R OH oo B rr l 3 „ ^ 1)NH 2 NH 2 *- • „ RR BBrr R SH CBr.JPh3P 2)OH" SCHEME B Thi'ols R-SH may be conveniently prepared from the corresponding readily available alcohols or halides via a two step replacement of halogen by sulfur, as described in Scheme B. Halides may be reacted with thiourea, and the corresponding alkyl thiouronium salts hydrolyzed to provide thiols RSH. If alcohols are used as the starting materials, they may be first converted to the corresponding halides by standard methods. Additional protecting groups and minor variations are contemplated as within the scope of the present invention and would be known to a person of ordinary skill in the art. In addition to the methods of making the compounds above, generalized methods and processes for making the compounds of the present invention contemplated as within the scope of the present invention are exemplified by the following Schemes C & D, wherein the compound of the left side of the equation may be contacted with the compound of the right side of the equation producing the novel inventive compounds of the present invention. SCHEME C Another generalized preferred Scheme for preparing the novel compounds of the present invention is exemplified by SCHEME D, below. SCHEME D Examples The following examples are illustrative of the present invention and are not intended to be limitations thereon. Unless otherwise specified, all percentages are based on 100% by weight of the final compound. Example 1 Synthesis of 3- ( 4-Methoxyphenyl) propyl (2S)-1- (phenylsulfonyl) -2-pyrrolidinecarbothioate (4) 3- (4-Methoxyphenyl) -1-propylbromide To a solution of 3- (4-methoxyphenyl ) -1-propanol (16.6 g; 0.1 mol) in 250 mL of toluene, cooled to 0°C, was added dropwise 26 mL of phosphorus tribromide (0.27 mol). Following completion of the addition the reaction was stirred at room temperature for 1 hour, then refluxed for an additional hour. The reaction was cooled and poured onto ice, the layers were separated, and the organic phase washed with saturated sodium bicarbonate (3x) and brine (3x) . The crude material obtained upon drying and evaporation of the solvent was chro atographed, eluting with 10% EtOAc/hexane, to obtain 14 g (61%) of 3- (4- methoxyphenyl) -1-propylbromide . 3- (4-Methoxyphenyl) -1-propylmercaotan A mixture of 3- (4-methoxyphenyl) -1-propylbromide (14 g; 61 mmol) and thiourea (5.1 g; 67 mmol) in ethanol (150 mL) was refluxed for 48 hours. Evaporation of the solvent provided a clear glassy compound, which was dissolved in 50 mL of water and treated with 100 L of 40% aqueous sodium hydroxide. After stirring the resulting mixture for two hours, the product was extracted into ether (3x), and the combined organic extracts were washed with sodium bicarbonate and brine, dried, and concentrated. Chromatographic purification of the crude thiol on a silica gel column eluting with 2% either in hexane delivered 10.2 g of 3- (4-methoxyphenyl) -1-propylmercaptan as a clear liquid l K NMR (300 MHZ, CDCl 3 ):δ 1.34 (t, 1H) ; 1.88- 1.92 (m, 2H); 2.49-2.53 (m, 2H) ; 2.64-2.69 (m, 2H) ; 3.77 (s, 3H) ; 6.80-6.84 (m, 2H) ; 7.06-7.24 (m, 2H) . 3- (4-Methoxyphenyl) N- ( tert-butyloxycarbonyl) -2- pyrrolidinecarbothioate A mixture of N- ( tert-butylyoxycarbonyl) - (S) - proline (2.0g; 9.29 mmol); 3- (4-methoxyphenyl) -1- propylmercaptan (1.86 g; 10.22 mmol), l-(3- dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (1.96 g; 10.22 mmol) and 4-dimethylaminopyridine (catalytic) in dry methylene chloride (50 mL) was stirred overnight. The reaction mixture was diluted with methylene chloride (50 mL) and water 100 ( L) , and the layers were separated. The organic phase was washed with water (3 x 100 mL) , dried over magnesium sulfate, and concentrated to provide 3.05 g of the product as a thick oil, l E NMR (300 MHZ, CDCl 3 ):δ 1.15 (s, 9H) ; 1.84-2.31 (m, 6H) ; 2.61 (m, 2H) ; 2.83 (m, 2H) ; 3.51 (m, 2H) ; 3.75 (s,3H); 6.79 (d,2H, J=8.04); 7.05 (m, 2H) . 3- (4-Methoxyohenyl) -2-pyrrolidinecarbothioate A solution of 3- ( 4-methoxyphenyl) N- ( tert- butylyoxycarbonyl) -2-pyrrolidinecarbothioate (3.0 g; 8.94 mmol) in methylene chloride (60 mL) and trifluoroacetic acid (6 mL) was stirred at room temperature for three hours. Saturated potassium carbonate was added until the pH was basic, and the reaction mixture was extracted with methylene chloride (3x) . The combined organic extracts were dried and concentrated to yield 1.73 g(69%) of the free arrαne as a thick oil, l E NMR (300 MHZ, CDCl 3 ):δ 1.80-2.23 (m, 6H) ; 2.62 (m, 2H) ; 2.81 (m, 2H) ; 3.01 (m, 2H) ; 3.75 (s,3H); 3.89(m, 1H); 6_.81 ( , 2H); 7.06 ( , 2H). 3- (4-Methoxγphenyl) propyl (2S) -1- (phenylsulfonyl) -2- pyrrolidinecarbothioate A solution of 3- ( -methoxyphenyl ) -2- pyrrolidinecarbothioate (567 mg; 2.03 mmol) and benzenesulfonyl chloride (358 mg; 2.03 mmol) in methylene chloride (5 mL) was treated with diisopropylethyla ine (290 mg; 2.23 mmol) and stirred overnight at room temperature. The reaction mixture was filtered to remove solids and applied directly to a silica gel column, eluting with 25% ethyl acetate in hexane, to obtain 540 mg of compound 4 (Table I) as a clear oil, : H NMR (300 MHZ, CDCl 3 ):δ 1.65-1.89 (m, 6H) ; 2.61 (t, 2H, J=7.3); 2.87 (t, 2H, J=7.6) ; 3.26(m,lH); 3.54 (m, 1H) ; 3.76 (s,3H); 4.34 (dd, 1H,J=2.7,8.6) ; 6.79 (d, 2H, J=8.7 ) ; 7.06(d, 2H, J=8.6); 7.49-7.59 (m, 3H) ; 7.86 (dd, 2H, J - 1.5,6.8). Thin Layer Chromatography yielded a result of R f = 0.36 (25% EtOAc: Hexane) . Example 2 Synthesis of 3- (4-Methoxγphenyl) prooyl (2S)-1- (benzylsulfonyl) -2-pyrrolidinecarbothioate (5) A solution of 3- ( 4-Methoxyphenyl ) -2- pyrrolidinecarbothioate (645 mg; 2.30 mmol) and benzylsulfonyl chloride (440 mg; 2.30 mmol) in methylene chloride (5 mL) was treated with diisopropylethylamine (330 mg; 2.53 mmol) and stirred overnight at room temperature. Purification as described for Example 1 provided the compound of Example 2 (Compound 5, Table I) as a clear oil, l E NMR (300 MHZ, CDC1 3 ) : δ 1.98-2.06 ( , 6H) ; 2.77 (t,2H, J=7.3) ; 3.02 ( t, 2H, J=7.3 ) ; 3.42 (m, 1H) ; 3.45 (m,2H); 3.91 (s,3H); 4.42-4.76 (m, 3H) ; 6.95 (d, 2H, J=8.6) ; 7.21 (d, 2H, J=8.6) ; 7.51 (m, 3H) ; 7.61- 7.64 (m, 2H). Thin Layer Chromatography yielded a result of R f = 0.36 (25% EtOAc :Hexane) . Example 3 Synthesis of 3- (4-Methoxyphenyl) propyl (2S)-l-[(4- methylphenyl) sulfonyl] -2-pyrrolidinecarbothioate (6) A solution of 3- ( 4-Methoxyphenyl ) -2- pyrrolidinecarbothioate (567 mg; 2.30 mmol) and (4- methylphenyl) sulfonyl chloride (425 mg; 2.23 mmol) in methylene chloride (5 mL) was stirred overnight at room temperature. Purification as described for Example 1 provided the compound of Example 3 (Compound 6, Table I) as a clear oil, l E NMR (300 MHZ, CDC1 3 ) : δ 1.67-1.94 (m,6H); 2.40(s,3H); 2.61 ( t, 2H, J=7.3) ; 2.84 (m,2H, J=7.2) ; 3.22 (m, 1H) ; 3.52 (m, 1H) ; 3.76 (s,3H); 4.32 (dd, 1H, J=2.9, 8.5) ; 6.79 (d, 2H, J=6.5 , ; 7.07 (d,2H, J=6.5) ; 7.29 (d, 2H, J=6.5) ; 7.74 (d, 2H, J=6.5) . Thin Layer Chromatography yielded a result of R f = 0.40 (25% EtOAc: Hexane) . As discussed above, the compounds of the present invention have an affinity for the FK506 binding protein, particularly FKBP12. The inhibition of the prolyl peptidyl ci s -trans isomerase activity of FKBP may be measured as an indicator of this affinity. Example 4 Synthesis of Phenethyl (2S)-l-[(4- ethylphenyl) sulfonyl] -2-pyrrolidinecarbothioate (21) The compound was prepared in accordance with the procedures used in the above examples and yielded and optically pure compound as a clear oil of molecular weight 403.55, molecular formula of C 21 H 2S N0 3 S 2 , H NMR (CDC1 3 , 300 MHZ): δ 1.52-2.02 ( , 9H) ; 2.68 (t,2H, J=8.6) ; 2.87 ( t, 2H, J=8.6) ; 3.27 (m, 1H) ; 3.53 (m,lH); 4.33 (m, 1H) ; 7.17 (m, 3H) ; ^.27 (m, 1H) ; 7.49- 7.65 (m, 3H); 7.85 (d, 2H, J=6.2) . Thin Layer Chromatography yielded a result of R f = 0.24 (25 EtOAc: Hexane) . Example 5 Synthesis of Phenethyl (2S) -1- (phenylsulfonyl) -2- pyrrolidinecarbothioate (22) The compound was prepared in accordance with the procedures used in the above examples and yielded an optically pure compound as an oil with a molecular weight of 389.53, molecular formula of C 2o H 23 N0 3 S 2 , l E NMR (CDC1 3 , 300 MHZ): δ 1.54-2.02 (m, 4H) ; 1.88 (q,2H, J=7.58) ; 2.67 (t, 2H, J=7.46) ; 2.87 (t, 2H, J=7.25) ; 3.21-3.29 (m,lH); 3.52-3.59 (m, 1H) ; 4.24 (d, 1H, J=8.44) ; 7.14-7.19 (m, 3H) ; 7.23-7.28 (m,2H); 7.49-7.62 (m,3H); 7.85 (d, 2H, J=7.66) . Thin Layer Chromatography yielded a result of R f = 0.25 (25% EtOAc: Hexane) . Example 6 Synthesis of 3-Phenylpropyl (2S)-1- (benzylsulfonyl) -2-pyrrolidinecarbothioate (23) The compound was prepared in accordance with the procedures used in the above examples and yielded an optically pure compound as a solid with a molecular weight of 403.56, molecular formula of C 21 H 25 N0 3 S 2 , melting point of 62-64°C, X H NMR (CDC1 3 , 300 MHZ) : δ 1.86-1.97 (m,5H); 2.05 (m, 1H) ; 2.70 ( t, 2H, J=7.29) ; 2.91 (t,2H, J=7.23) ; 3.15 (m, 1H) ; 3.29 (m, 1H) ; 4.41 (m,3H); 7.18 (m, 3H) ; 7.28 (m, 2H) ; 7.38 (m, 3H) ; 7.48 (m, 2H). Thin Layer Chromatography yielded a result of R f = 0.27 (25% EtOAc/Hexane) . Example 7 Synthesis of 3- (1-Naphthyl) propyl (2S)-1- (benzylsulfonyl) -2-pyrrolidinecarbothioate (24) The compound was made in accordance with the procedures followed in the above examples and yielded an optically active compound as a clear oil with a molecular weight of 453.62, molecular formula of C 25 H 27 N0 3 S 2 , : H NMR (CDC1 3 , 300 MHZ): δ 1.81-2.06 (m, 6H) ; 2.98 (t,2H, J=7.2) ; 3.15 ( , 3H) ; 3.29 (m, 1H) ; 4.30-4.44 (m,3H); 7.29-7.51 (m, 9H) ; 7.71 (d, 1H, J=8.1) ; 7.82 (d, 1H, J=8.1) ; 8.00 (d, 1H, J=8.1) . Thin Layer Chromatography yielded a result of R f = 0.26 (25% EtOAc/Hexane) . Example 8 Synthesis of 3-Phenylpropyl (25)-l-[(4- ethylphenyl) sulfonyl] -2-pyrrolidinecarbothioate (25) The compound was made in accordance with the procedures used in the above examples and yielded an optically pure compound as a clear oil with a molecular weight of 417.58, molecular formula of C 22 H 7 N0 3 S 2 , ! H NMR (CDC1 3 , 300 MHZ): δ 1.39-2.02 (m, 9H) ; 2.73 (m, 4H); 2.89 (t, 2H, J=7.5) ; 3.27 (m, 1H) ; 3.53 (m,lH); 4.35 (d, 1H, J=8.2) ; 7.14-7.52 (m, 7H) ; 7.73 (d, 2H, J=7.2) . Thin Layer Chromatography yielded a result of R f = 0.39 (25% EtOAc/hexane) . Example 9 Synthesis of 3- (4-Methoxyphenyl) propyl l-[(4- methylphenyl) sulfonyl] -2-piperidinecarbothioate (26) The compound was prepared in accordance with the procedures used in the above examples and yielded a racemic compound as a clear oil with a molecular weight of 447.55, molecular formula of C 23 H 29 N0 4 S 2 , " Η NMR (CDC1 3 , 300 MHZ): δ 1.25-1.32 (m, 2H) ; 1.45-1.52 (m,4H); 1.78-1.85 (m,2H); 2.19 (bd, 1H, J=4.59) ; 2.38 (s,3H); 2.58 ( t, 2H, J=6.88 ) ; 2.79 ( t, 2H, J=6.73 ) ; 3.15- 3.24 (m,lH); 3.76 (s,3H); 4.72-4.74 (m, 1H) ; 6.80 (d, 2H, J=8.39) ; 7.04 (d, 2H, J=8.61 ) ; 7.24 (d,2H, J=10.53) ; 7.70 (d, 2H, J=8.53) . Thin Layer Chromatography yielded a result of R f = 0.35 (25% EtOAc/hexane ) Example 10 Synthesis of 3- ( 4-Methoxyphenyl ) propyl 1- (benzyl sul fonyl ! ■ 2-piperidinecarbothioate ( 27 ; The compound was prepared in accordance with the procedures followed in the above examples and yielded a racemic compound as a clear oil with a molecular weight of 447.55, molecular formula of C 23 H 2? N0 3 S 2 , l E NMR (CDC1 3 , 300 MHZ): δ 1.28-1.64 (m, 5H) ; 1.82-1.92 (m,2H); 2.20 (bd, 1H, J=14.51 ) ; 2.62 (t, 2H, J=7.54) ; 2.90 (t,2H, J=7.36) ; 3.13 (dt, 1H, J=2.56, 12.93 ) ; 3.49 (bd, 1H, J=12.84) ; 3.76 (s,3H); 4.27 (s,2H); 4.55-4.56 (m,lH); 6.80 (d, 2H, J=8.54) ; 7.06 (d, 2H, J=8.39) ; 7.32- 7.35 (m, 3H) ; 7.43-7.46 (m, 2H). Thin Layer Chromatography yielded a result of R f = 0.32 (25% EtOAc/hexane) . Example 11 Synthesis of 3- ( 4-Methoxyphenyl) propyl 1- (phenylsulfonyl ) - 7 -piperidinecarbothioate (28 ) The compound was prepared in accordance with the procedures followed in the above examples and yielded a racemic compound as a clear oil with molecular weight of 433.55, molecular formula of C 22 H 24 NS 2 0 4 , l E NMR (CDC1 3 , 300 MHZ): δ 1.31-1.47 (m, IH) ; 1.51-1.56 (m,4H); 1.80 (q, 2H, J=7.45, 14.95); 2.21 (bd, IH, J=13.36) ; 2.58 ( t , 2H, J=7.49 ) ; 2.79 (t,2H, J=7.19) ; 3.18-3.26 (m, IH) ; 3.77 (s,3H); 3.83 (bd, IH, J=13.54) ; 4.74-4.76 (m, IH) ; 6.81 (d, 2H, J=8.56) ; 7.05 (d,2H, J=8.43) ; 7.44-7.54 (m, 3H) ; 7.83 (d, 2H, J= .52) . Thin Layer Chromatography yielded a result of R f = 0.37 (25% EtOAc/hexane). Example 12 Synthesis of 3- [4- (Trifluoromethyl) phenyl] propyl 1- [ (4-methylphenyl) sulfonyl] -2-piperidinecarbothioate (29) The compound was prepared in accordance with the procedures in the above examples and yielded a racemic compound with molecular weight of 485.46, molecular formula of C^H^NC^S, , α H NMR (CDC1, , 300 MHZ): δ 1.19- 1.34 (m,3H); 1.46-1.53 (m,2H); 1.87-2.03 (m,2H); 2.13- 2.34 (m,lH); 2.41 (s,3H); 2.71 ( t , 2H, J=7.4 ) ; 2.87 (t,2H, J=7.36) ; 3.20-3.35 (m, IH) ; 3.87 (bd, IH, J=7.91 ) ; 4.80-4.83 (m, IH) ; 7.31-7.40 (m, 4H) ; 7.50-7.58 (m,2H); 7.80-7.87 (m,2H). Thin Layer Chromatography yielded a result of R. = 0.66 (50% Hexane : EtOAc) . Ki Test Procedure The compounds of the invention are shown to inhibit peptidyl-prolyl isomerase (rotamase) activity and can be evaluated by known methods described in the literature (Harding,- et al . , Na ture, 1989, 341:758- 760; Holt et al . J. Am. Chern.. Soc , 115:9923-9938). These values are obtained as apparent Ki ' s and are presented in Tables 11(a) and 11(b). The cis-trans isomerization of an alanine-proline bond in a model substrate, N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide, is monitored spectrophotometrically in a chy otrypsin- coupled assay, which releases para-nitroanilide from the trans form of the substrate. The inhibition of this reaction caused by the addition of different concentrations of inhibitor is determined, and the data is analyzed as a change in first-order rate constant as a function of inhibitor concentration to yield the apparent Ki values. In a plastic cuvette are added 950 mL of ice cold assay buffer (25 mM HEPES, pH 7.8, 100 mM NaCl), 10 mL of FKBP (2.5 mM in 10 mM Tris-Cl pH 7.5, 100 mM NaCl, 1 mM dithiothreitol) , 25 mL of chymotrypsin (50 mg/ml in 1 mM HCl) and 10 mL of test compound at various concentrations in dimethyl sulfoxide. The reaction is initiated by the addition of 5 mL of substrate (succinyl-Ala-Phe-Pro-Phe-para-nitroanilide, 5 mg/mL in 2.35 mM LiCl in trifluoroethanol) . The absorbance at 390 nm versus time is monitored for 90 seconds using a spectrophotometer and the rate constants are determined from the absorbance versus time data files. The data for these experiments for representative compounds are presented in Tables 11(a) and 11(b) under the column "Ki". The neurotrophic effects of the compounds of the present invention can be demonstrated in cellular biological experiments in vitro, as described below. Chick Dorsal Root Ganglion Cultures and Neurite Outgrowth Dorsal root ganglia were dissected from chick embryos of ten day gestation. Whole ganglion explants were cultured on thin layer Matrigel-coated 12 well plates with Liebovitz L15 plus high glucose media supplemented with 2 mM glutamine and 10% fetal calf serum, and also containing 10 μM cytosine β-D arabinofuranoside (Ara C) at 37°C in an environment containing 5% C0 . Twenty-four hours later, the DRGs were treated with various immunophilin ligands. Forty-eight hours after drug treatment, the ganglia were visualized under phase contrast or Hoffman Modulation contrast with a Zeiss Axiovert inverted microscope. Photomicrographs of the explants were made, and neurite outgrowth was quantitated. Neurites longer than the DRG diameter were counted as positive, with total number of neurites quantitated per each experimental condition. Three to four DRGs are cultured per well, and each treatment was performed in duplicate . The data for these experiments for representative compounds are presented in Table II (c) under the column "ED £0 " . TABLE II (a) In Vitro Test Results Ex. No. Ki,nM f 1 4-++ 2 ++ 3 4-+ 4 + 5 +++ 6 ++ 7 ++ 8 4-++ 9 4-4-+ 10 +++ 11 ++ 12 +++ 13 +++ 14 +++ 15 +++ 16 ++ 21 * 22 * 23 ++ 24 * 25 * 26 * 27 * 28 ++ 29 + + Table II (b ) Numeri . cal In Vitro Test Results Ex. No. Ki,nM T 4 204 5 22 6 145 21 780 22 551 23 107 24 671 25 984 26 659 27 82 28 196 29 69 TABLE II ( c) Chick DRG In Vitro Neurite Test Results Ex. No. ED50.nM T 1 ++++ 2 +++ 3 +++ 4 ++ 5 +++ 6 ++ 7 +++ 8 ++++ 9 ++++ 10 +++ 11 +++ 12 +++ 13 ++++ 14 +++ 15 ++++ 16 ++ Relative potencies of compounds are ranked according to the following scale: ++++ denotes Ki or ED50 < 1 nM; +++ denotes Ki or ED50 of 1-50 nM; ++ denotes Ki or ED 50 of 51-200 nM; + denotes Ki or ED50 of 201-500 nM; * denotes Ki or ED50 of > 500nM. MPTP Model of Parkinson's Disease The remarkable neurotrophic and neuroregenerative effects of the present inventive compounds can be further demonstrated in an animal model of neurodegenerative disease. MPTP lesioning of dopaminergic neurons in mice is used as an animal model of Parkinson's Disease. Four week old male CD1 white mice are dosed i.p. with 30 mg/kg of MPTP for 5 days. Test compounds (4 g/kgj , or vehicle, are administered s.c. along with the MPTP for 5 days, as well as for an additional 5 days following cessation of MPTP treatment. At 18 days following MPTP treatment, the animals are sacrificed and the striata dissected and perfusion-fixed. Immunostaining is performed on saggital and coronal brain sections using anti-tyrosine hydroxylase 1 g to quantitate survival and recovery of dopaminergic neurons. In animals treated with MPTP and vehicle, a substantial loss of functional dopaminergic terminals is observed as compared to non-lesioned animals. Lesioned animals receiving test compounds show a significant recovery of TH-stained dopaminergic neurons. This model presents quantitation for the recovery of TH-positive dopaminergic neurons in the striatum of animals receiving the compounds of the present invention. Data for representative control and lesioned animals not receiving the test drugs is also presented against the data from the animals receiving the compounds of the present invention in Table III. Table III MPTP Model of Parkinson's Disease Test Results Comp . No . % Recovery Tyrosine Hydroxylase 4 42 6 37 23 80 24 40 The phrase "preventing neurodegeneration" relates to the remarkable ability of the compounds of the present invention to significantly prevent nerve damage when the compounds are given concurrently with a lesioning agent, such as MPTP. This also provides a reasonable correlation between the scope of the claims and the ability to prevent neurodegeneration in patients newly diagnosed as having a neurodegenerative disease, or at risk of developing a neurodegenerative disease. The compounds also provide methods for preventing fur t her neurodegeneration in patients who are already suffering from or have symptoms of a neurodegenerative disease. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications are intended to be included within the scope of the following claims.

Claims: WHAT IS CLAIMED IS 1. A compound of formula I or a pharmaceutically acceptable salt, ester, or solvate thereof, wherein: A and B are taken together, with the nitrogen and carbon atoms to which they are respectively- attached, to form a 5-7 memoered saturated or unsaturated heterocyclic ring containing any combination of CH_, 0, S, SO, SO , NH or NR. in any chemically stable oxidation state; X is either 0 or S; Y is a direct bond to Z, a C^C * , straight or branched chain alkyl, or a C 2 -C c straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted m one or more positions with ammo, halo, naloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, linino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R, is selected from the group consisting of hydrogen, (C,-C 6 ) -straight or branched chain alkyl, (C 3 -C 6 ) -straight or branched chain alkenyl or alkynyl, and (C : -C ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR : and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; Z is a direct bond, or a C : -C 6 straight or branched chain alkyl, or a C ; -C„ straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R_ is selected from the group consisting of hydrogen, (C,-C 3 ) -straight or branched chain alkyl, (C ιi -C 6 ) -straight or branched chain alkenyl or alkynyl, and bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR X and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; C and D are independently: hydrogen, Ar, Cj-Cg straight or branched chain alkyl, or C_,-C,, straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more position (s) with C 3 -C 3 cycloalkyl, C=-C- cycloalkenyl, hydroxyl, carbonyl oxygen, or Ar, wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl groups are optionally substituted with C : -C 6 alkyl, C-C 6 alkenyl, hydroxy, amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 : , wherein R 2 is selected from the group consisting of hydrogen, (C-_- C-; -straight or branched chain alkyl, (C.-C )- straight :r branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; wherein Ar is an aryl or heteroaryl moiety which is substituted or unsubstituted; and R η is selected from the group consisting of Ar, C - C y cycloalkyl, C_-C„ straight or branched chain alkyl, C_-C_ straight or branched chain alkenyl, or C_-C 3 straight or branched chain alkyl or C_-C, straight or branched chain alkenyl which is substituted in one or more positions with Ar, ammo, halo, haloalkyl, hydroxy, trifluoromethyl, C-,-C 6 straight or branched chain alkyl, C_-C straight or brancheα chain alkenyl, caroonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, substituted alkyl or alkenyl wherein any of the carbon atoms of the alkyl or alkenyl are optionally replaced with S, SO, SO_, 0, or NR wnerem R is selected from the group consisting cf hydrogen, (C^-C 6 ) -straight or brancheα chain alkyl, (C^-Ci,) -straight :r branche cnam alkenyl or alkynyl, and (C,-C bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group or C 3 -C cycloalkyl. 2. The compound of claim 1, wherein Ar is a cyclic or fused cyclic ring and includes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to five position (s) with halo, haloalkyl, hydroxyi, nitro, trifluoromethyl, C : -C 3 straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, C-_-C. alkoxy, C_-C alkenyloxy, phenoxy, benzyioxy, amino, thiocarbonyl, ester, thioester, cyano, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-3 members; wherein the heterocyclic ring contains 1-4 heteroatom (s ) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a corresponding N-oxide. 3. The compound of claim 2, wherein the mono- or bicyclic, carbo- or -heterocyclic ring is selected from the group consisting of phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, furyl, thiophenyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl . 4. The compound of claim 1, wherein the compound has an affinity for FKBP-type immunophilins. 5. The compound of claim 4, wherein the FKBP-type immunophilins are FKBP12. 6. The compound of claim 1, wherein the compound inhibits rotamase enzyme activity. 7. A compound selected from the group consisting of: 3- ( 4-Methoxyphenyl ) propyl (2S ) -1- (phenylsulfonyl ) - 2-pyrrolidinecarbcthioate; 3- (4-Methoxyphenyl ) propyl (2S) -1- (benzylsulfonyl ι - 2-pyrrolidinecarbothioate; 3- (4-Methoxyphenyl) propyl (2S) -1- [ (4-methyl phenyl) sulfonyl] -2-pyrrolidinecarbothioate; (2, 2-Phenylmethyi! ethyl (2S) -1- [ ( -ethylphenyl) sulfonyl] -2-pyrrolidinecarbothioate; 3-Phenylpropyl (2S)--1- (phenylsulfonyl) -2- pyrrolidinecarbothioate; 3-Phenylpropyl (2S) -1- (benzylsulfonyl) -2- pyrrolidinecarbothioate; 3- (1-Naphthyl) propyl (2S) -1- (benzylsulfonyl) -2- pyrrolidinecarbothioate; 3-Phenylpropyl (2S) -1- [ ( 4-ethylphenyl) sulfonyl] -2- pyrrolidinecarbothioate; 3- (4-Methoxyphenyl) propyl 1- [ ( 4-methylphenyl) sulfonyl] -2-piperidinecarbothioate; 3- (4-Methoxyphenyl) propyl 1- (benzylsulfonyl) -2- piperidinecarbothioate; 3- (4-Methoxyphenyl) propyl 1- (phenylsulfonyl) -2- piperidinecarbothioate; 3- [4- (Trifluoromethyl) phenyl] propyl 1- [ ( -methyl phenyl) sulfonyl] -2-piperidinecarbothioate; and a pharmaceutically acceptable salt, ester, or solvate thereof. 8. A pharmaceutical composition comprising a neurotrophically effective amount of the compound of claim 1 and a pharmaceutically acceptable carrier. 9. A method of effecting a neuronal activity in an animal, comprising: administering to the animal a neurotrophically effective amount of " the compound of claim 1. 10. The method of claim 9, wherein the neuronal activity is selected from the group consisting of stimulation of damaged neurons, promotion of neuronal regeneration, prevention of neurodegeneration and treatment of neurological disorder . 11. The method of claim 10, wherein the neurological disorder is selected from the group consisting of peripheral neuropathy caused by physical injury or disease state, physical damage to the brain, physical damage to the spinal cord, stroke associated with brain damage, and neurological disorder relating to neurodegeneration. 12. The method of claim 11, wherein the neurological disorder relating to neurodegeneration is selected from the group consisting of Alzheimer's Disease, Parkinson's Disease, and amyotrophic lateral sclerosis. 13. A compound of formula II: II or a pharmaceutically acceptable salt, ester, or solvate thereof, wherein: E, F, G, and H are independently CH 2 , 0, S, SO, S0 : , NH or NR 2 ; X is either 0 or S; Y is a direct bond to Z, a C--C straight or branched chain alkyl, or a C-C £ straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR., S, SO, or S0 : , wherein R ; is selected from the group consisting of hydrogen, (C : -C -straight or branched chain alkyl, (C : .-C„-) -straight or branched chain alkenyl or alkynyl, and (C τ -C.) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; Z is a direct bond, or a straight or branched chain alkyl, or a C 2 -C 0 - straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR : , S, SO, or S0, wherein R 2 is selected from the group consisting of hydrogen, (C-_-C ; ) -straight or branched chain alkyl, (C,-C. ) -straight or branched chain alkenyl or alkynyl, and (C x -C,) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR : and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic r ng ;s optionally fused to an Ar group; C and D are independently: hydrogen, Ar, C,-C fe " straight or branched chain alkyl, or C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more position (s) with C 3 -C 8 cycloalkyl, C 5 -C 7 cycloalkenyl, hydroxyl, carbonyl oxygen, or Ar, wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl groups are optionally substituted with C-_-C._ alkyl, C -C, alkenyl, hydroxy, amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR_, 3, SO, or S0 : , wherein R_ is selected from the group consisting of hydrogen, (C-- C,-) -straight or branched chain alkyl, (C_.-C.J- straight or branched chain alkenyl or alkynyl, and (C,-CJ bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of R : and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; wherein A.r is an aryl or heteroaryl moiety which is substituted or unsubstituted; and Rι is selected from the group consisting of Ar, C 3 - C 8 cycloalkyl, straight or branched chain alkyl, C 2 -C 5 straight or branched chain alkenyl, or C ^ -Cg straight or branched chain alkyl or C 2 -C 6 straight or branched chain alkenyl which is substituted in one or more positions with Ar, amino, halo, haloalkyl, hydroxy, trifluoromethyl, C-_-C, straight or branched chain alkyl, C-C„- straight or branched chain alkenyl, carbonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, substituted alkyl or alkenyl wherein any of the carbon atoms of the alkyl or alkenyl are optionally replaced with S, SO, SO_, 0, or NR : wherein P is selected from the group consisting of hydrogen, (C ^ -C,.) -straight or branched chain alkyl, (C 3 -CJ -straight or branched chain alkenyl or alkynyl, and (C,-CJ bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group or C,-C_ cycloalkyl. 14. The compound of claim 13,. wherein Ar is a cyclic or fused cyclic ring and includes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to five position (s) with halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, C,-C„ straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, C,-Cς alkoxy, C 2 -C 6 alkenyloxy, phenoxy, benzyloxy, amino, thiocarbonyl, ester, thioester, cyano, imino, aikyiaminc, aminoalkyl, sulfhydryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-8 members; wherein the heterocyclic ring contains 1-4 heteroatom ( s ) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a corresponding N- oxide . 15. The compound of claim 14, wherein Ar is selected from the group consisting of phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, furyl, thiophenyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl . The compound of- claim 13, wherein the compound has an affinity for FKBP-type .immunophilins . 17. The compound of claim 16, wherein the FKBP-type immunophilins are FKBP12. 18. The compound of claim 13, wherein the compound inhibits rotamase enzyme activity. 19. A pharmaceutical composition comprising a neurotrophically effective amount of the compound of claim 13 and a pharmaceutically acceptable carrier. 20. A method of effecting a neuronal activity in an animal, comprising: administering to the animal a neurotrophically effective amount of the compound of claim 13. 21. The method of claim 20, wherein the neuronal activity is selected from the group consisting of stimulation of damaged neurons, promotion of neuronal regeneration, prevention of neurodegeneration and treatment of neurological disorder . 22. The method of claim 21, wherein the neurological disorder is selected from the group consisting of peripheral neuropathy caused by physical injury or disease state, physical damage to the brain, physical damage to the spinal cord, stroke associated with brain damage, and neurological disorder relating to neurodegeneration. 23. The method of claim 22, wherein the neurological disorder relating to neurodegeneration is selected from the group consisting of Alzheimer's Disease, Parkinson's Disease, and amyotrophic lateral sclerosis. 24. A compound of formula III III or a pharmaceutically acceptable salt, ester, or solvate thereof, wherein: E, F, and G are independently CH : , 0, S, SO, S0 : , NH or NR 2 ; X is either 0 or S; Y is a direct bond- to Z, a C- . -C, straight or branched chain alkyl, or a C 2 -C 3 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R : is selected from the group consisting of hydrogen, (C,_-C -straight or branched chain alkyl, (C 3 -C -straight or branched chain alkenyl or alkynyl, and (C_-C.J bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR : and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; Z is a direct bond, or a C : -C 6 straight or branched chain alkyl, or a C-C_ straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitre, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R 2 is selected from the group consisting of hydrogen, (C X -C -straight or branched chain alkyl, (C 3 -C -straight or branched chain alkenyl or alkynyl, and (C x -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; C and D are independently: hydrogen, Ar, C__-C, ; straight or branched chain alkyl, or C 2 -C straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or mere position (s) with C-.-C. cycloalkyl, C d -C- cycloalkenyl, hydroxyl, carbonyl oxygen, or Ar, wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl groups are optionally substituted with C,-C b alkyl, C_-C, alkenyl, hydroxy, amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R 2 is selected from the group consisting of hydrogen, (C-- C -straight or branched chain alkyl, (C 3 -CJ- straight or branched chain alkenyl or alkynyl, and (C .. -CJ bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; wherein Ar is an aryl or heteroaryl moiety which is substituted or unsubstituted; and R : is selected from the group consisting of Ar, C - Co cycloalkyl, C : -C ; straight or branched chain alkyl, C_-C„ straight or branched chain alkenyl, or C,-C 6 straight or branched chain alkyl or C 2 -C ; straight or branched chain alkenyl which is substituted in one or more positions with Ar, amino, halo, haloalkyl, hydroxy, trifluoromethyl, C,_-C. straight or branched chain alkyl, C 2 -C 3 straight or branched chain alkenyl, carbonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, substituted alkyl or alkenyl wherein any of the carbon atoms of the alkyl or alkenyl are optionally replaced with S, SO, SO., 0, or NR, wherein R 2 is selected from the group consisting of hydrogen, (C,_-C -straight or branched chain alkyl, (C 3 -CJ -straight or branched chain alkenyl or alkynyl, and (C 1 -C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group or C„-C_ cycloalkyl. 25. The compound of claim 24, wherein Ar is a cyclic or fused cyclic ring and incluαes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted m one to five position (s) with halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, C -C straight or branched chain alkyl, C_-C„ straight or branched chain alkenyl, C : -C b alkoxy, C__-C 3 alkenyloxy, phenoxy, benzyloxy, ammo, thiocarbonyl, ester, thioester, cyano, imino, alkylamino, aminoalkyl, sulfhyαryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-3 members; wherein tne heterocyclic ring contains 1-4 heteroatom (s) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a correspondinσ N- oxide . 5 26. The compound of claim 25, wherein Ar is selected from the group consisting of phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, 10 furyl, thiophenyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl. 27. The compound of claim 24, wherein the compounα has an affinity for FKBP-type immunophilins. 15 28. The compound of claim 27, wherein the FKBP-type immunophilins are FK3P12. 29. The compound of claim 24, wherein the compound 20 inhibits rotamase enzyme activity. 30. A pharmaceutical composition comprising a neurotrophically effective amount of the compound of claim 24 and a pharmaceutically acceptable carrier. "5 31. A method of effecting a neuronal activity in an animal, comprising: administering to the animal a neurotrophically effective amount of the compound of claim 24. 32. The method of claim 31, wherein the neuronal activity is selected from the group consisting of stimulation of damaged neurons, promotion of neuronal regeneration, prevention of neurodegeneration and treatment of neurological disorder. 33. The method of claim 32, wherein the neurological disorder is selected from the group consisting of peripheral neuropathy caused by physical injury or disease state, physical damage to the brain, physical damage to the spinal cord, stroke associated with brain damage, and neurological disorder relating to neurodegeneration. 34. The method of claim 33, wherein the neurological disorder relating to neurodegeneration is selected from the group consisting of Alzheimer's Disease, Parkinson's Disease, and amyotrophic lateral sclerosis. 35. A compound of formula IV IV or a pharmaceutically acceptable salt, ester, or solvate thereof, wherein: n is 1, 2 or 3 forming a 5-7 member heterocyclic ring; X is either 0 or S; Y is a direct bond to Z, a straight or branched chain alkyl, or a C 2 -C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR,, S, SO, or S0 2 , wherein R 2 is selected from the group consisting of hydrogen, (C_-CJ -straight or branched chain alkyl, (C.-C ) -straight or branched chain alkenyl or alkynyl, and (C,-CJ bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR : and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; Z is a direct bond, or a C x -C 6 straight or branched chain alkyl, or a C,-C 6 straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R 2 is selected from the group consisting of hydrogen, (C,-C,J -straight or branched chain alkyl, (C.-CJ -straight or branched chain alkenyl or alkynyl, and (C,-C bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR- and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; C and D are independently: hydrogen, Ar, C-_-C. : straight or branched chain alkyl, or C -C straight or branched chain alkenyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more position (s) with C 3 -C 8 cycloalkyl, C 5 -C 7 cycloalkenyl, hydroxyl, carbonyl oxygen, or Ar, wherein said alkyl, alkenyl, cycloalkyl or cycloalkenyl groups are optionally substituted with C x -Cg alkyl, C,-C t alkenyl, hydroxy, amino, halo, haloalkyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, wherein any of the carbon atoms of said alkyl or alkenyl are optionally substituted in one or more positions with oxygen to form a carbonyl, or wherein any of the carbon atoms of said alkyl or alkenyl are optionally replaced with 0, NH, NR 2 , S, SO, or S0 2 , wherein R 2 is selected from the group consisting of hydrogen, (C_- C -straight or branched chain alkyl, (C 3 -CJ - straight or branched chain alkenyl or alkynyl, and (C,-C 4 ) bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group; wherein Ar is an aryl or heteroaryl moiety which is substituted or unsubstituted; and R x is selected from the group consisting of Ar, C-,- C 3 cycloalkyl, Cn-Cg straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, or Ci_-C 6 straight or branched chain alkyl or C 2 -C 6 straight or branched chain alkenyl which is substituted in one or more positions with Ar, amino, halo, haloalkyl, hydroxy, trifluoromethyl, C-_-C 6 straight or branched chain alkyl, C 2 -C ε straight or branched chain alkenyl, carbonyl, thiocarbonyl, ester, thioester, alkoxy, alkenoxy, cyano, nitro, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, sulfonyl, substituted alkyl or alkenyl wherein any of the carbon atoms of the alkyl or alkenyl are optionally replaced with S, SO, S0 2 , 0, or NR 2 wherein R_ is selected from the group consisting of hydrogen, (C,_-CJ -straight or branched chain alkyl, (C 3 -CJ -straight or branched chain alkenyl or alkynyl, and (C,-CJ bridging alkyl wherein said bridging alkyl forms a heterocyclic ring starting with the nitrogen of NR, and ending with one of the carbon atoms of said alkyl or alkenyl chain, and wherein said heterocyclic ring is optionally fused to an Ar group or C 3 -C cycloalkyl. 36. The compound of- claim 35, wherein Ar is a cyclic or fused cyclic ring and includes a mono-, bi- or tricyclic, carbo- or heterocyclic ring, wherein the ring is either unsubstituted or substituted in one to five position (s) with halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, C--C straight or branched chain alkyl, C 2 -C 6 straight or branched chain alkenyl, C x -C 3 alkoxy, C,-C 6 alkenyloxy, phenoxy, benzyloxy, amino, thiocarbonyl, ester, thioester, cyano, imino, alkylamino, aminoalkyl, sulfhydryl, thioalkyl, and sulfonyl; wherein the individual ring sizes are 5-8 members; wherein the heterocyclic ring contains 1-4 heteroatom (s ) selected from the group consisting of 0, N, or S; wherein aromatic or tertiary alkyl amines are optionally oxidized to a corresponding N- oxide . 37. The compound of claim 36, wherein Ar is selected from the group consisting of phenyl, benzyl, naphthyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, furyl, thiophenyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, and thienyl. 38. The compound of claim 35, wherein the compound has an affinity for -FKBP-type immunophilins. 39. The compound of claim 38, wherein the FKBP-type immunophilins are FKBP12. 40. The compound of claim 35, wherein the compound inhibits rotamase enzyme activity. 41. A pharmaceutical composition comprising a neurotrophically effective amount of the compound of claim 35 and a pharmaceutically acceptable carrier. 42. A method of effecting a neuronal activity in an animal, comprising: administering to the animal a neurotrophically effective amount of the compound of claim 35. 43. The method of claim 42, wherein the neuronal activity is selected from the group consisting of stimulation of damaged neurons, promotion of neuronal regeneration, prevention of neurodegeneration and treatment of neurological disorder . 44. The method of claim 43, wherein the neurological disorder is selected from the group consisting of peripheral neuropathy caused by physical injury or disease state, physical damage to the brain, physical damage to the spinal cord, stroke associated with brain damage, and neurological disorder relating to neurodegeneration. 45. The method of claim 44, wherein the neurological disorder relating to neurodegeneration is selected from the group consisting of Alzheimer's Disease, Parkinson's Disease, and amyotrophic lateral sclerosis. 46. A process for preparing a compound of Formula I, II, III, or IV, which comprises: contacting a compound of structure (a) with a compound of structure (b) , HS — R (b) wherein said contacting results in a compound of Formula I, II, III, or IV. 47. A process for preparing a compound of Formula I, II, III, or IV, which comprises: contacting a compound of structure (a) with a compound of structure (b) wherein said contacting results in a compound of Formula I, II, III, or IV.

Inventors: HAMILTON GREGORY S, HUANG WEI, LI JIA-HE, HAMILTON, GREGORY, S., HUANG, WEI, LI, JIA-HE
Applicants: GUILFORD PHARM INC, GUILFORD PHARMACEUTICALS INC.
Application year: 1997
Main classification: A61K31
IPC codes: A61K31, C07D207, C07D211