| PATENT ASSIGNEE'S COUNTRY | USA |
| UPDATE | 04.00 |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 25.04.00 |
| PATENT TITLE |
Kappa agonist compounds pharmaceutical formulations and method of prevention and treatment of pruritis therewith |
| PATENT ABSTRACT |
Compounds having kappa opioid agonist activity, compositions containing them and method of using them as analgesics and anti-pruritic agents are provided. The compound of formulae IIA, having the structure: ##STR1## wherein R.sub.1, R.sub.2 ; X.sub.4, X.sub.5 ; and Ar and n are as described in the specification. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | 07.05.99 |
| PATENT REFERENCES CITED | This data is not available for free |
| PATENT PARENT CASE TEXT | This data is not available for free |
| PATENT CLAIMS |
1. A method for the prevention or treatment of pruritus in a patient comprising administering to said patient an effective amount of a compound of formula IIA or a pharmaceutically acceptable salt thereof ##STR299## wherein n=1-3, R.sub.1 and R.sub.2 are independently=CH.sub.3 ; --(CH.sub.2).sub.m, where m=4-8, --CH.sub.2 CH(OR)(CH.sub.2).sub.2 -- wherein R is H, alkyl, acyl or aroyl; CH.sub.2 CH(F)(CH.sub.2).sub.2 --; --(CH.sub.2).sub.2 O(CH.sub.2).sub.2 --; or --(CH.sub.2).sub.2 CH.dbd.CHCH.sub.2 --; Ar=mono- or di-substituted phenyl; wherein said substituents are selected from the group consisting of halogen, OCH.sub.3, OH, SO.sub.2 CH.sub.3, CF.sub.3, NH.sub.2, alkyl, CN, unsubstituted and substituted sulfamoyl groups; or Ar substituted with --NH(CH.sub.2).sub.u CO.sub.2 R'; --NH(CH.sub.2).sub.u (CH.dbd.CH).sub.u (CH.sub.2)CO.sub.2 R'; --NHCO(CH.sub.2).sub.u (CH.dbd.CH).sub.u (CH.sub.2).sub.u CO.sub.2 R'; --NHP(O)(OBn).sub.2 ; --NHP(O)(OR').sub.2 ; --(CH.sub.2).sub.u NHSO.sub.2 CH.sub.3 ; --(CH.sub.2).sub.u NHC(S)NHCH(CO.sub.2 R')(CH.sub.2).sub.u CO.sub.2 R'; --CONHOH; or --(CH.sub.2).sub.u CONHOH; wherein u=0-5; R'=H or lower alkyl; or Ar is ##STR300## X.sub.4 and X.sub.5 are independently H; halogen; OH; OCH.sub.3 ; CF.sub.3 ; NO.sub.2 ; NH.sub.2 ; amino substituted with acyl, carbamate, alkyl or aryl sulfonates; COR' where R' is OH, amide, alkoxy, aryloxy or heteroaryloxy. -------------------------------------------------------------------------------- |
| PATENT DESCRIPTION |
BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to compounds, to processes of their preparation, to pharmaceutical compositions containing them and to their medical use as agonists at kappa opioid receptors. The present invention also relates to compositions and method for the treatment and/or prevention of itch, also known as pruritus, which has many causes. The compositions, which are formulated for topical and systemic administration, contain kappa opiate receptor agonists that are substantially devoid of central nervous system effects, and, thus, have very little, if any potential for producing side effects associated with centrally acting kappa opiate receptor agonists. 2. Reported Developments A) Kappa (.kappa.)-receptor Agonists as Analgesics Opium and its derivatives are potent analgesics that also have other pharmacological effects, and exert their effects by interacting with high-affinity receptors. It has been shown by investigators that there are at least three major opioid receptor types in the central nervous system (hereinafter CNS) and in the periphery. These receptors, known as mu (.mu.), delta (.delta.) and kappa (.kappa.), have distinct pharmacological profiles, anatomical distributions and functions. [See, for example: Wood, P. L., Neuropharmacology, 21, 487-497, 1982; Simon, E., J. Med. Res. Rev., 11, 357-374, 1991; Lutz et al., J. Recept. Res. 12, 267-286; and Mansour et al., Opioid I, ed. Herz,. A. (Springer, Berlin) pp. 79-106, 1993.] The .delta. receptors are abundant in CNS and mediate analgesia, gastrointestinal motility and various hormonal functions. The .mu. receptors bind morphine-like drugs and mediate the opiate phenomena associated with morphine, including analgesia, opiate dependence, cardiovascular and respiratory functions, and several neuroendocrine effects. The .kappa. receptors have a wide distribution in CNS and mediate a spectrum of functions including the modulation of drinking, water balance, food intake, gut motility, temperature control and various endocrine functions. They also produce analgesia. [See, for example: Leander et al., J. Pharmacol. Exp. Ther. 234, 463-469, 1985; Morley et al., Peptides 4, 797-800, 1983; Manzanares et al., Neuroendocrinology 52, 200-205, 1990; and Iyengar et al., J. Pharmacol. Exp. Ther., 238, 429-436, 1986. ] Most clinically used opioid analgesics such as morphine and codeine act as .mu. receptor agonists. These opioids have well-known, undesirable and potentially dangerous dependence forming side effects. Compounds which are .kappa.-receptor agonists act as analgesics through interaction with .kappa. opioid receptors. The advantage of these agonists over the classical .mu. receptor agonists, such as morphine, lies in their ability to cause analgesia while being devoid of morphine-like behavioral effects and addiction liability. A large number of classes of compounds which act as agonists at .kappa. opioid receptors have been described in the art including the following illustrative classes of compounds. U.S. Pat. No. 4,065,573 discloses 4-amino-4-phenylcyclohexane ketal compounds having analgesic activity. U.S. Pat. No. 4,212,878 discloses phenylacetamide derivatives having analgesic properties and reduced physical dependence liability properties, relative to morphine and methadone. U.S. Pat. No. 4,145,435 discloses N-(2-amino-cycloaliphatic)-phenylacetamide compounds having analgesic activity and narcotic antagonist activity. U.S. Pat. No. 4,098,904 discloses N-(2-amino-cycloaliphatic)-benzoamides and naphthamides useful for relieving pain. U.S. Pat. No. 4,359,476 discloses substituted cycloalkane-amides useful as analgesics and having low abuse liability. U.S. Pat. No. 4,438,130 discloses 1-oxa-, aza- and thia-spirocyclic compounds having analgesic activity, low physical dependence and abuse liability properties and little dysphoric inducing properties. U.S. Pat. No. 4,663,343 discloses substituted naphthalenyloxy-1,2-diaminocyclohexyl amides as analgesics. U.S. Pat. No. 4,906,655 discloses 1,2-cyclohexylaminoaryl amides having high kappa-opioid affinity, selectivity and potency and useful as analgesics, diuretics, anti-inflammatory and psychotherapeutic agents. B) Kappa (.kappa.)-receptor Agonists as Anti-Pruritic Agents The prior art has investigated the physiology and treatment of pruritus as illustrated hereunder. Itch is a well known sensory state associated with the desire to scratch. As with pain, itch can be produced by a variety of chemical, mechanical, thermal or electrical stimuli. In addition to the difference in the sensory quality of itch and pain, they also differ in that (1) itch, unlike pain, can only be evoked from the superficial layers of skin, mucosa, and conjunctiva, and (2) itch and pain usually do not occur simultaneously from the same skin region; in fact, mildly painful stimuli, such as scratching, are effective in eliminating itch. In addition, the application of histamine to skin produces itch but not pain. Itch and pain are further dissociated pharmacologically: itch appears to be insensitive to opiate and non-steroidal anti-inflammatory drug (NSAID) treatment, both of which are effective in treating pain. Although itch and pain are of a class in that both are modalities of nociception transmitted by small unmyelinated C fibers, evidence that itch is not just a variety of low-threshold pain is overwhelming. Itch leads to the reflex or urge to scratch; pain leads to withdrawal. Itch occurs only in the skin; pain arises from deeper structures as well. Heat may stop pain but usually increases pain. Removal of the epidermis eliminates itch but causes pain. Analgesics, particularly opioids, relieve pain but often cause itch (see, for example J. Am. Acad. Derm. 24: 309-310, 1991). There can be no doubt that itching is of eminent clinical importance; many systemic and skin diseases are accompanied by persistent or recurrent itch attacks. Current knowledge suggests that itch has several features in common with pain but exhibits intriguing differences as well (see, for example, W. Magerl, IASP Newsletter, pp. 4-7, Sept/Oct 1996). McMahon et al. (TINS, Vol. 15, No. 12, pp. 497-501, 1992) provides a description of stimuli (Table a) and a comparison of the established features of itch and pain (Table b): TABLE a ______________________________________ Stimuli that can elicit or augment itch ______________________________________ Physical Mechanical. Light touch, pressure, suction. Thermal. Warming. Electrical. Focal transcutaneous repetitive stimulation, transcutaneous constant current stimulation, intraneural microstimulation. Chemical Non-specific irritants. Acids, alkalis. Inflammatory mediators. Histamine, kallikrein, bradykinin, prostaglandins. Histamine-releasing substances. Compound 48/80, protamine, C3a. Peptidases. Mucunain, papain, trypsin, mast cell chymase. Neuropeptides. Substance P, vasoactive intestinal polypeptide, neurotensin, secretin. Opioids. Morphine, .beta.-endorphin enkephalin analogues. ______________________________________ TABLE b ______________________________________ Comparison of the established features of itch and pain ITCH PAIN ______________________________________ Psychophysiology Tissue Skin. Mucous membranes Most tissues Stimulus See Table a Many stimuli Intraneural microstimulation Occasionally Yes Secondary sensations Alloknesis (itchy skin) Hyperalgesia Psychogenic modification Pronounced Present Counterstimuli Scratching, pain, cooling Tactile stimuli, cooling Neurophysiology Primary afferent neurones C- and A.delta.-fibres C- and A.delta.- fibres Flare size Large Small Spinal pathway Anterolateral funiculus Anterolateral funiculus Protective reflexes Scratching, sneezing Flexion, guarding Autonomic reflexes Yes Yes Pharmacology Capsaicin sensitivity Yes Chemogenic pain; yes NSAID sensitivity Probably not Yes Morphine sensitivity No Yes ______________________________________ Abbreviation: NSAID, nonsteroidal antiinflammatory drugs. Experimental focal itch stimuli are surrounded by a halo of seemingly unaffected tissue where light tactile stimuli are capable of eliciting itch-like sensations. The term itchy skin or alloknesis has been coined for these secondary sensations that are reminiscent of the features of secondary hyperalgesia evolving around a painful focus. A crucial observation is that itch and pain usually do not coexist in the same shin region and a mild noxious stimulus such as scratching is in fact the singly most effective way to abolish itch. This abolition of itch can be prolonged producing an `antipruritic state`. Although mild scratch is often not painful, microneurographic recordings from humans have directly determined that such stimuli are among the most effective ways to excite cutaneous unmyelinated nociceptive afferents. (See, for example: Shelly, W. B. and Arthur, R. P. (1957) Arch. Dermatol. 76, 296-323; Simone, D. A. et al.. (1987) Somatosens. Res. 5, 81-92; Graham, D. T., Goodell, H. and Wolff, H. G. (1951) J. Clin. Invest. 30, 37-49; Simone, D. A., Alreja, M. and LaMotte, R. H. (1991) Somatosens Mot. Res. 8, 271-279; Torebjork, E (1985) Philos. Trans. R. Soc. London Ser. B 308, 227-234; and Vallbo, A. B., Hagbarth, K. E., Torebjork, H. E. and Wallin, B. G. (1970) Physiol. Rev. 59, 919-957). Physiologically, there is evidence that substance P released from nociceptor terminals can cause the release of histamine from mast cells. Activation of mast cells, with release of the pruritogen histamine, occurs in immediate type hypersensitivity diseases, such as anaphylactic reactions and urticaria. Urticarial eruptions are distinctly pruritic and can involve any portion of the body, and have a variety of causes beyond hypersensitivity, including physical stimuli such as cold, solar radiation, exercise and mechanical irritation. Other causes of pruritus include: chiggers, the larval form of which secretes substance that creates a red papule that itches intensely; secondary hyperparathyroidism associated with chronic renal failure; cutaneous larva migrans, caused by burrowing larvae of animal hookworms; dermal myiasis, caused by maggots of the horse botfly, which can afflict horseback riders; onchocerciasis ("river blindness") caused by filarial nematodes; pediculosis, caused by lice infestations; enterobiasis (pinworm) infestations, which afflict about 40 million Americans, particularly school children; schistosome dermatitis (swimmer's itch); and asteatotic eczema ("winter itch"). The role of histamine or other endogenous pruritogens in mediating itch associated with these and other pruritic conditions, such as atopic dermatitis, it is not yet well established. For atopic dermatitis, in particular, it appears that itch is not inhibited by antihistamines, but by cyclosporin A, a drug which inhibits the production of cytokines which have been proposed as potential pruritogens. Current therapies for the treatment of itch include a variety of topical and systemic agents, such as steroids, antihistamines, and some psychotherapeutic tricyclic compounds, such as doxepin hydrochloride. Many such agents are listed in PDR Generics (see Second Edition, 1996, p. cv for a listing of said agents). The limitations of these agents are well known to medical practitioners, and are summarized in the "Warnings" and "Precautions" sections for the individual agents listed in PDR Generics. In particular, the lack of complete efficacy of antihistamines is well known, but antihistamines are frequently used in dermatology to treat pruritus due to urticaria, atopic dermatitis, contact dermatitis, psoriasis, and a variety of other conditions. Although sedation has been a frequent side effect of conventional systemically administered antihistamines, a new generation of antihistamines have been developed that are nonsedating, apparently due to their inability to cross the blood-brain barrier. Intravenous administration of opiate analgesics, such as morphine and hydromorphone has been associated with pruritus, urticaria, other skin rashes, wheal and flare over the vein being injected. These itch and itch-related reactions are believed to be due to a histamine-releasing property of these opiates, via mast cell degranulation. These opiates are thought to act upon the mu subtype of opiate receptor, but the possibility of interactions at the other principal opiate receptor subtypes (delta and kappa) cannot be excluded since these and other pruritogenic analgesics are not pure my agonists. The cellular loci of the receptor type(s) mediating the itching effect is not known, although the mast cell is a possible candidate since opiates cause histamine release from these cells. However, some investigators have suggested that the frequent inability of antihistamines to block morphine-induced itching suggests a non-histaminergic mediation of opiate-induced itching--a mechanism which could involve central opiate receptors. Although i.v. morphine only occasionally results in generalized itching (in about 1% of patients), pruritus is more prevalent in opiate analgesia with epidural (8.5%) or intraspinal (45.8%) administration. (See, for example: Bernstein et al.., "Antipruritic Effect of an Opiate Antagonist, Naloxone Hydrochloride", The Journal of Investigative Dermatology, 78:82-83, 1982; and Ballantyne et al.., "Itching after epidural and spinal opiates", Pain, 33: 149-160, 1988.) To date, treatment with opiates has not only proven useless in the treatment of itch, but appears to exacerbate itch in man. The consistent findings form human studies indicate that whether by central or peripheral mechanisms, opiates appear to promote rather than prevent itching, and that opiate antagonists have anti-pruritic activity. Human clinical studies have generally shown that opiates cause itching and there is evidence that these effects can be reproduced in animal models, where itching sensations per se cannot be reported, but scratching behavior can be observed. (See, for example: Thomas et al.., "Microinjection of morphine into the rat medullary dorsal horn produces a dose-dependent increase in facial-scratching", Brain Research, 195: 267-270, 1996; Thomas et al.., "Effects of central administration of opioids on facial scratching in monkeys", Brain Res., 585: 315-317, 1992; and Thomas et al.., "The medullary dorsal horn: A site of action of opioids in producing facial scratching in monkeys", Anesthesiology, 79: 548-554, 1993). We have now surprisingly discovered that kappa agonist compounds, which are substantially devoid of central nervous system effects, in pharmaceutically acceptable vehicles for systemic and topical formulations possess anti-pruritic activity in addition to anti-hyperalgesic activity. SUMMARY OF THE INVENTION Compounds having kappa opioid agonist activity, compositions containing them and method of using them as analgesics are provided. In its compound aspect, the present invention provides a compound of the formulae I, II, IIA, III, IIIA, IV and IVA, or a pharmaceutically acceptable salt thereof. The compounds of formula (I) have the following structure: ##STR2## wherein n=1-3, where n=1 is preferred R.sub.1 and R.sub.2 are independently=CH.sub.3 ; --(CH.sub.2).sub.m, where m=4-8, m=4 is most preferred; --CH.sub.2 CH(OH)(CH.sub.2).sub.2 --; CH.sub.2 CH(F)(CH.sub.2).sub.2 --; --(CH.sub.2).sub.2 O(CH.sub.2).sub.2 --; or --(CH.sub.2).sub.2 CH.dbd.CHCH.sub.2 --; Ar=unsubstituted or mono- or di-substituted phenyl wherein said substituents are selected from the group consisting of halogen, OCH.sub.3, SO.sub.2 CH.sub.3, CF.sub.3, amino, alkyl, and 3,4-dichloro; benzothiophenyl; benzofuranyl; naphthyl; diphenyl methyl; or 9-fluorene; Z is --P(O)(OBn).sub.2 ; --P(O)(OH).sub.2 ; --(CH.sub.2).sub.p C(O)NHOH; --(CH.sub.2).sub.p CO.sub.2 H; --SO.sub.2 CH.sub.3 ; --SO.sub.2 NH.sub.2 ; --CO(CH.sub.2).sub.p CH(NH.sub.2)(CO.sub.2 H); --COCH(NH.sub.2)(CH.sub.2).sub.p CO.sub.2 H; --CO.sub.2 CH.sub.3 ; --CONH.sub.2 ; --(CH.sub.2).sub.p O(CH.sub.2).sub.p CO.sub.2 H; --(CH.sub.2).sub.p O(CH.sub.2).sub.p CONHOH; --(CH.sub.2).sub.p NHSO.sub.2 CH.sub.3 ; --(CH.sub.2).sub.p NHC(S)NHCH(CO.sub.2 H)(CH.sub.2).sub.p CO.sub.2 H; --(CH.sub.2).sub.p SO.sub.3 H; or ##STR3## or Z is ##STR4## wherein p=0-20; R.sub.3 =--H or --Ac; X.sub.2 =--CO.sub.2 H; --NHSO.sub.2 CH.sub.3 ; NHP(O)(OBn).sub.2 ; NHP(O)(OH).sub.2 ; --OP(O)(OBn).sub.2 ; or OP(O)(OH).sub.2 ; X and Y are independently --CH.sub.2 NHSO.sub.2 CH.sub.3, --CH.sub.2 NHP(O)(OBn).sub.2, --CH.sub.2 NHP(O)(OH).sub.2, --CH.sub.2 OP(O)(OBn).sub.2, --CH.sub.2 OP(O)(OH).sub.2, --(CH.sub.2).sub.q O(CH.sub.2).sub.q CO.sub.2 H, --(CH.sub.2).sub.q SO.sub.3 H, --(CH.sub.2).sub.q O(CH.sub.2).sub.q CHNHOH, --CH.sub.2 NHC(S)NHCH(CO.sub.2 H)(CH.sub.2).sub.q CO.sub.2 H or ##STR5## wherein r=1-20 R4=--H or --Ac X.sub.3 =--CO.sub.2 H; --NHSO.sub.2 CH.sub.3 ; --NHP(O)(OBn).sub.2 ; --NHP(O)(OH).sub.2 ; --OP(O)(OBn).sub.2 ; or --OP(O)(OH).sub.2. The compounds of formula II have the following structure: ##STR6## wherein n=1-3, where n=1 is preferred R.sub.1 and R.sub.2 are independently=CH.sub.3 ; --(CH.sub.2).sub.m, where m=4-8, m=4 is most preferred; --CH.sub.2 CH(OH)(CH.sub.2).sub.2 --; CH.sub.2 CH(F)(CH.sub.2).sub.2 --; --(CH.sub.2).sub.2 O(CH.sub.2).sub.2 --; or --(CH.sub.2).sub.2 CH.dbd.CHCH.sub.2 --; Ar=unsubstituted or mono- or di-substituted phenyl wherein said substituents are selected from the group consisting of halogen, OCH.sub.3, SO.sub.2 CH.sub.3, CF.sub.3, amino, alkyl, and 3,4-dichloro; benzothiophenyl; benzofuranyl; naphthyl; diphenyl methyl; or 9-fluorene; X.sub.4 and X.sub.5 are independently --OP(O)(OBn).sub.2 ; --OP(O)(OH),; --CO.sub.2 H; --SO.sub.3 H; --SO.sub.3 H; --O(CH.sub.2).sub.n CO.sub.2 H; --NHSO.sub.2 CH.sub.3 ; --CONH(CH.sub.2).sub.s CO.sub.2 H; or --SO.sub.2 NH(CH.sub.2).sub.s CO.sub.2 H; wherein s=1-5 or X.sub.4 and X.sub.5 are independently ##STR7## wherein t=1-20 R.sub.5 =--H or --Ac X.sub.6 =--CO.sub.2 H; --NHSO.sub.2 CH.sub.3 ; --NHP(O)(OBn).sub.2 ; --NHP(O)(OH).sub.2 ; --OP(O)(OBn).sub.2 ; or --OP(O)(OH).sub.2. The compounds of formula IIA have the following structure: ##STR8## wherein n=1-3, where n=1 is preferred R.sub.1 and R.sub.2 are independently=CH.sub.3 ; --(CH.sub.2).sub.m, where m=4-8, m=4 is most preferred; --CH.sub.2 CH(OR)(CH.sub.2).sub.2 -- wherein R is H, alkyl, acyl or aroyl; CH.sub.2 CH(F)(CH.sub.2).sub.2 --; --(CH.sub.2).sub.2 O(CH.sub.2).sub.2 --; or --(CH.sub.2).sub.2 CH.dbd.CHCH.sub.2 --; Ar=mono- or di-substituted phenyl; wherein said substituents are selected from the group consisting of halogen, OCH.sub.3, OH, SO.sub.2 CH.sub.3, CF.sub.3, NH.sub.2, alkyl, CN, unsubstituted and substituted sulfamoyl groups; Ar may also be substituted with --NH(CH.sub.2).sub.u CO.sub.2 R'; --NH(CH.sub.2).sub.u (CH.dbd.CH).sub.u (CH.sub.2)CO.sub.2 R'; --NHCO(CH.sub.2).sub.u (CH.dbd.CH).sub.u (CH.sub.2).sub.u CO.sub.2 R'; --NHP(O)(OBn).sub.2 ; --NHP(O)(OR').sub.2 ; --(CH.sub.2).sub.u NHSO.sub.2 CH.sub.3 ; --(CH.sub.2).sub.u NHC(S)NHCH(CO.sub.2 R')(CH.sub.2).sub.u CO.sub.2 R'; --CONHOH; or --(CH.sub.2).sub.u CONHOH; wherein u=0-5; R'=H or lower alkyl; or Ar is ##STR9## X.sub.4 and X.sub.5 are independently H; halogen; OH; OCH.sub.3 ; CF.sub.3 ; NO.sub.2 ; NH.sub.2 ; amino substituted with acyl, carbamate, alkyl or aryl sulfonates; COR' where R'is OH, amide, alkoxy, aryloxy, or heteroaryloxy. Compounds of formula (IIA) have at least one chiral center and may exist in more than one diastereoisomeric form. The invention includes within its scope all enantiomers, and diastereosomers and the mixtures thereof. The compounds of formula III have the following structure: ##STR10## wherein n=1-3, where n=1 is preferred R.sub.1 and R.sub.2 are independently=CH.sub.3 ; --(CH.sub.2).sub.m, where m=4-8, m=4 is most preferred; --CH.sub.2 CH(OH)(CH.sub.2).sub.2 --; CH.sub.2 CH(F)(CH.sub.2).sub.2 --; --(CH.sub.2).sub.2 O(CH.sub.2).sub.2 --; or --(CH.sub.2).sub.2 CH.dbd.CHCH.sub.2 --; Ar=unsubstituted or mono- or di-substituted phenyl wherein said substituents are selected from the group consisting of halogen, OCH.sub.3, SO.sub.2 CH.sub.3, CF.sub.3, amino, alkyl, and 3,4-dichloro; benzothiophenyl; benzofuranyl; naphthyl; diphenyl methyl; or 9-fluorene; X.sub.7 is --NHSO.sub.2 CH.sub.3 ; --NHP(O)(OBn).sub.2 ; --NHP(O)(OH).sub.2 ; --(CH.sub.2).sub.u NHSO.sub.2 CH.sub.3 ; --(CH.sub.2).sub.u NHC(S)NHCH(CO.sub.2 H)(CH.sub.2).sub.u CO.sub.2 H; --CONHOH; or --(CH.sub.2).sub.u CONHOH; wherein u=1-5 or X.sub.7 is ##STR11## The compounds of formula IIIA have the following structure: ##STR12## wherein n=1-3, where n=1 is preferred; R.sub.1 and R.sub.2 are independently=CH.sub.3 ; --(CH.sub.2).sub.m, where m=4-8, m=4 is most preferred; --CH.sub.2 CH(OR)(CH.sub.2).sub.2 --, wherein R.dbd.H, alkyl, acyl or aroyl; CH.sub.2 CH(F)(CH.sub.2).sub.2 --; --(CH.sub.2).sub.2 O(CH.sub.2).sub.2 --; or --(CH.sub.2).sub.2 CH.dbd.CHCH.sub.2 ; Ar=mono- or di-substituted phenyl; wherein said substituents are selected from the group consisting of halogen, OCH.sub.3, OH, SO.sub.2 CH.sub.3, CF.sub.3, NH2, alkyl, CN, unsubstituted and substituted sulfamoyl groups; Ar may also be substituted with --NH(CH.sub.2).sub.u CO.sub.2 R'; --NH(CH.sub.2).sub.u (CH.dbd.CH).sub.u (CH.sub.2)CO.sub.2 R'; --NHCO(CH.sub.2).sub.u (CH.dbd.CH).sub.u (CH.sub.2).sub.u CO.sub.2 R'; --NHP(O)(OBn).sub.2 ; --NHP(O)(OR').sub.2 ; --(CH.sub.2).sub.u NHSO.sub.2 CH.sub.3 ; --(CH.sub.2).sub.u NHC(S)NHCH(CO.sub.2 R')(CH.sub.2).sub.u CO.sub.2 R'; --CONHOH; or --(CH.sub.2).sub.u CONHOH; wherein u=0-5; R'=H or lower alkyl; or Ar is ##STR13## X.sub.7 is H; halogen; OH; OCH.sub.3 ; CF.sub.3 ; NO.sub.2 ; NH.sub.2 ; amino substituted with acyl, carbamate, alkyl or aryl sulfonates; COR' where R' is OH, amide, alkoxy, aryloxy or heteroaryloxy. Compounds of formula (IIIA) have at least one chiral center and may exist in more than one diastereoisomeric form. The invention includes within its scope all enantiomers, and diastereosomers and the mixtures thereof. The compounds of formula IV have the following structure: ##STR14## wherein n=1-3, where n=1 is preferred R.sub.1 and R.sub.2 are independently=CH.sub.3 ; --(CH.sub.2).sub.m, where m=4-8, m=4 is most preferred; --CH.sub.2 CH(OH)(CH.sub.2).sub.2 --; CH.sub.2 CH(F)(CH.sub.2).sub.2 --; --(CH.sub.2).sub.2 O(CH.sub.2).sub.2 --; or --(CH.sub.2).sub.2 CH.dbd.CHCH.sub.2 --; R.sub.3 and R.sub.4 are independently H; OCH.sub.3 ; alkyl; or C--O(CH.sub.2).sub.2 ; X.sub.9 =1-4 substituents selected from the groups consisting of --halogen; --CF.sub.3 ; --OCH.sub.3 ; --SO.sub.2 NH(CH.sub.2).sub.q CO.sub.2 H; --CONH(CH.sub.2).sub.q CO.sub.2 H; --NH.sub.2 ; --NHSO.sub.2 CH.sub.3 ; --NHP(O)(OBn).sub.2 ; --NHP(O)(OH).sub.2 ; --SO.sub.2 CH.sub.3 ; --OP(O)(OBn).sub.2 ; --OP(O)(OH).sub.2 ; --CO.sub.2 H; --O(CH.sub.2).sub.q CO.sub.2 H; --O(CH.sub.2).sub.q SO.sub.3 H, --O(CH.sub.2).sub.q OPO.sub.3 H.sub.2 ; wherein q=1-20. or X.sub.9 is ##STR15## wherein t=1-20 R.sub.5 =--H or --Ac X.sub.6 =--CO.sub.2 H; --NHSO.sub.2 CH.sub.3 ; --NHP(O)(OBn).sub.2 ; --NHP(O)(OH).sub.2 ; --OP(O)(OBn).sub.2 ; or --OP(O)(OH).sub.2. The compounds of formula IVA have the following structure: ##STR16## wherein n=1-3, where n=1 is preferred R.sub.1 and R.sub.2 are independently=CH.sub.3 ; --(CH.sub.2).sub.m, where m=4-8, m=4 is most preferred; --CH.sub.2 CH(OR)(CH.sub.2).sub.2 --; wherein R.dbd.H, alkyl, acyl, or aroyl; CH.sub.2 CH(F)(CH.sub.2).sub.2 --; --(CH.sub.2).sub.2 O(CH.sub.2).sub.2 --; or --(CH.sub.2).sub.2 CH.dbd.CHCH.sub.2 --; R.sub.3 and R.sub.4 are independently H; OCH.sub.3 ; alkyl; or --O(CH.sub.2).sub.2 ; X.sub.9 =1-4 substituents selected from the groups consisting of --halogen; --CF.sub.3 ; OH, --OCH.sub.3 ; --SO.sub.2 NH(CH.sub.2).sub.q CH.sub.3 ; --NH(CH.sub.2).sub.q COR'; --NH(CH.sub.2).sub.q (CH.dbd.CH).sub.q (CH.sub.2).sub.q CO.sub.2 R'; --NH(CH).sub.q (CH.tbd.CH).sub.q (CH).sub.q CO.sub.2 R; --NHCO(CH.sub.2).sub.q (CH.dbd.CH).sub.q (CH.sub.2).sub.q CO.sub.2 R; and --NHCO(CH).sub.q (CH.dbd.CH).sub.q (CH).sub.q CO.sub.2 R' wherein q=0-20 R'=OH, lower alkyl, aryl ester or aryl amide. Compounds of formula (IVA) have at least one chiral center and may exist in more than one diastereoisomeric form. The invention includes within its scope all enantiomers, and diastereosomers and the mixtures thereof. The meaning of the terms used in the specification and the claims, unless otherwise denoted, are as follows. The term "alkyl" as used herein alone or as part of another group, denotes optionally substituted, straight and branched chain saturated hydrocarbon groups, preferably having 1 to 12 carbons in the normal chain, most preferably lower alkyl groups. Exemplary unsubstituted groups include methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl and the like. Exemplary substituents include one or more of the following groups: halo, alkoxy, arylalkyloxy (e.g., benzyloxy), alkylthio, alkenyl, alkynyl, aryl, cycloalkyl, cycloalkenyl, hydroxy, carboxyl (--COOH), amino, alkylamino, dialkylamino, formyl, alkylcarbonyloxy, alkylcarbonyl, heterocyclo, aryloxy or thiol (--SH). Preferred alkyl groups are unsubstituted alkyl, haloalkyl, arylalkyl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, alkoxyalkyl, aryloxyalkyl, hydroxyalkyl and alkoxyalkyl groups. The term "lower alkyl" as used herein denotes such optionally substituted groups as described above for alkyl having 1 to 4 carbon atoms in the normal chain. The terms "ar" or "aryl"as used herein or as part of another group, denote optionally substituted, homocyclic aromatic groups, preferably containing 1 or 2 rings and 6 to 12 ring carbons. Exemplary unsubstituted groups include phenyl, biphenyl and naphthyl. Exemplary substituents include one or more, preferably three or fewer, nitro groups, alkyl groups as described above, and/or one or more groups described above as alkyl substituents. Preferred aryl groups are unsubstituted aryl and hydroxyaryl. The terms "heterocyclo" or "heterocyclic" as used herein alone or as part of another group, denote optionally substituted fully saturated or unsaturated, aromatic or non-aromatic cyclic groups having at least one heteroatom in at least one ring, preferably monocyclic or bicyclic groups having 5 or 6 atoms in each ring. The heterocyclo group may, for example, having 1 or 2 oxygen atoms, 1 or 2 sulfur atoms, and/or 1 to 4 nitrogen atoms in the ring. Each heterocyclo group may be bonded through any carbon or heteroatom off the ring system. Preferred groups include those of the following formula, which may be bonded through any atom of the ring system: ##STR17## wherein r is 0 or 1 and T is --O--, --S--, --N--R.sup.8 or --CH--R.sup.8 where R.sup.8 is hydrogen, alkyl, aryl or arylalkyl. Exemplary heterocyclo groups include the following: thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, pyrrolidinyl, piperidinyl, azepinyl, indolyl, isoindolyl, quinolinyl, isoquinolinyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, morpholinyl, piperazinyl, 4-alkylpiperazinyl, 4-alkylpiperidinyl, 3-alkpyrrolidinyl, oxazolyl, pyrazolyl, thiophenyl, pyridazinyl, thiazolyl, triazolyl, pyrimidinyl, 1,4-dioxanyl, benzoxadiazolyl, and benzofurazanyl. Exemplary substituents include one or more alkyl groups as described above and/or one or more groups described above as alkyl substituents. The terms "halogen" or "halo" as used herein alone or as part of another group, denote chlorine, bromine, fluorine and iodine. The term "acyl", as used herein alone or as part of another group, denotes the moiety formed by removal of the hydroxyl group from the group --COOH of an organic carboxylic acid. Exemplary groups include alkycarbonyl, arylcarbonyl, or carbocyclo- or heterocyclocarbonyl. The term "acyloxy", as used herein alone or as part of another group denotes an acyl group as described above bonded through an oxygen linkage (--O--). DETAILED DESCRIPTION OF THE INVENTION Peripherally-acting .kappa. anonists can be prepared by the attachment of polar groups to non-peptide .kappa. opioid receptor selective agonists, such as the arylacetamides. In designing the peripherally-acting ligands, the introduction of the polar groups may result in either retention or enhancement of antionociceptive potency and selectivity and also may increase the polarity of the ligand sufficient to reduce or eliminate CNS penetration across the blood-brain barrier (BBB). Thus, the identity and the positioning of the polar group(s) are important. Using the prototypic arylacetamide, U50,488, as an example, the arylacetamide pharmacophore can be divided into three regions: the aromatic region, the central region, and the amide region. All three regions represent potential positions for the attachment of polar groups. ##STR18## Compounds of formula (I) of the present invention are made as follows. A series of novel compounds were made based on the class of arylacetamides reported by Glaxo (J. Med. Chem. 1993, 36, 2075). Specifically, compound 1 can be deprotected to yield intermediate 2, which can be derivatized by the attachment of a variety of polar groups (Scheme 1). ##STR19## The 3'-substituted series can be prepared via Scheme 2. The reduction of the Schiff base intermediate formed during the cyclization to 6 is expected to be stereoselective due to the directing effect of the neighboring hydroxymethyl group. Both intermediates 11 and 12 can be derivatized to confer peripheral selectively. The 5'-substituted series can be prepared via Schemes 3 and 4. Starting from N-t-Boc-O-MEM-D-serine, the 5'-(S) series can be prepared, and starting from from N-t-Boc-O-MEM-L-serine allows the preparation of the 5'-(R) series. ##STR20## wherein Ar, R.sub.1, R.sub.2, and n are defined in formula I. ##STR21## wherein Ar, R.sub.1, R.sub.2, and n are as defined in formula I. ##STR22## wherein Ar, R.sub.1, R.sub.2, and n are as defined in formula I. ##STR23## wherein Ar, R.sub.1, R.sub.2, and n are as defined in formula I. Using Schemes 1-4 the following example compounds are made. Intermediate 3 can be treated with t-butyl bromoacetate and deprotected to produce {4-[1-(3,4-Dichlorophenyl)acetyl-2R-(1-pyrrolidinyl)methyl]piperazinyl}ace tic acid (26). Intermediate 3 can be reacted with methane sulfonyl chloride to produce [1-(3,4-Dichlorophenyl)acetyl-4-methanesulfonyl-2R-(1-pyrrolidinyl)methyl] piperazine (27). Intermediate 3 can be coupled to N-t-Boc-L-aspartic acid-b-benzyl ester and deprotected to produce [4-S-Aspartic acid-a-amido-1-(3,4-dichlorophenyl)acetyl-2R-(1-pyrrolidinyl)methyl]pipera zine (28). Intermediate 11 can be treated with t-butyl bromoacetate and deprotected to produce Methyl-[2R-(O-2-acetic acid)hydroxymethyl-4-(3,4-dichlorophenyl)acetyl-3R-(1-pyrrolidinyl)methyl] -1-piperazinecarboxylate (29). Intermediate 11 can be coupled to N-t-Boc-L-aspartic acid-b-benzyl ester and deprotected to produce Methyl-[2R-(O-S-aspartic acid-a-acetyl)hydroxymethyl-4-(3,4-dichlorophenyl)acetyl-3R-(1-pyrrolidiny l)methyl]-1-piperazinecarboxylate (30). Intermediate 12 can be treated with methanesulfonyl chloride to produce Methyl-[4-(3,4-dichlorophenyl)acetyl-2R-(N-methanesulfonamide)aminomethyl- 3R-(1-pyrrolidinyl)methyl]-1-piperazine (31). Intermediate 12 can be coupled to 2S-isothiocyanato succinic acid-dibenzyl ester and deprotected to yield Methyl-{4-[3,4-dichlorophenyl]acetyl-3R-[1-pyrrolidinyl]methyl-2R-[N-(succ inic acid-2-S-thioureido)]aminomethyl}-1-piperazinecarboxylate (32). Intermediate 21 can be treated with t-butyl bromoacetate and deprotected to produce Methyl-[2S-(O-2-acetic acid)hydroxymethyl-4-(3,4-dichlorophenyl)acetyl-5R-(1-pyrrolidinyl)methyl] -1-piperazine (33). Intermediate 21 can be coupled to N-t-Boc-L-aspartic acid-b-benzyl ester and deprotected to produce Methyl-[2S-(O-S-aspartic acid-a-acetyl)hydroxymethyl-4-(3,4-dichlorophenyl)acetyl-5R-(1-pyrrolidiny l)methyl]-1-piperazinecarboxylate (34). Intermediate 22 can be treated with methanesulfonyl chloride to produce Methyl-[4-(3,4-dichlorophenyl)acetyl-2S-(N-methanesulfonamido)aminomethyl- 5R-(1-pyrrolidinyl)methyl]-1-piperazinecarboxylate (35). Intermediate 22 can be coupled to 2S-isothiocyanato-succinic acid-dibenzyl ester and deprotected to yield Methyl-{4-[3,4-dichlorophenyl]acetyl-5R-[1-pyrrolidinyl]methyl-2S-[N-(succ inic acid-2S-thioureido)]aminomethyl}-1-piperazinecarboxylate (36). The 2R isomers of 33-34 and 35-36 can be prepared from intermediates 24 and 25, respectively to produce Methyl-[2R-(O-2-acetic acid)hydroxymethyl-4-(3,4-dichlorophenyl)acetyl-5R-(1-pyrrolidinyl)methyl] -1-piperazinecarboxylate (37). Methyl-[2R-(O-S-aspartic acid-a-acetyl)hydroxymethyl-4-(3,4-dichlorophenyl)acetyl-5R-(1-pyrrolidnyl )methyl]-1-piperazinecarboxylate (38). Methyl-[4-(3,4-dichlorophenyl)acetyl-2R-(N-methanesulfonamido)aminomethyl-5 -R-(1-pyrrolidnyl)methyl]-1-piperazinecarboxylate (39). Methyl-{4-(3,4-dichlorophenyl)acetyl-5R-[1-pyrrolidinyl]methyl-2R-[N-succin ic acid-2S-thioureido)]aminoemethyl}-1-piperazinecarboxylate (40). The corresponding structural formulas are shown hereunder. ##STR24## Compounds of formula II of the present invention are made by peripheralization by substitutions of the benzo portion of the tetrahydronaphthyl ring of DuPont series of compounds with polar groups. ##STR25## Starting material or precursors of the starting material are commercially available and thus allows regiospecific substitutions of the tetrahydronaphthyl ring (Scheme 5). While 5-hydroxytetralone, 6-hydroxytetralone, 7-hydroxytetralone, and 7-aminotetralone derivatives are readily available, 5-aminotetralone could be prepared from 5-hydroxytetralone (J. Org. Chem. 1972, 37, 3570). The tetralone derivatives can be converted to dihydronaphthyl derivatives and subjected to chemistry similar to that employed in the preparation of U50,488 derivatives. The resulting compounds are racemic mixtures that can be derivatized to confer peripheral selectively. If necessary, the final compounds or one of the intermediates can be resolved to test both enantiomers. ##STR26## wherein R.sub.2,R.sub.2, and n are as defined in formula I. Following the procedure shown in Schemes 5-7, the following example compounds are prepared. Intermediate (.+-.)-64 can be treated with t-butyl bromoacetate and deprotected to produce (.+-.)-2-(3,4-dichlorophenyl)-N-methyl-N-1-[1,2,3,4-tetrahydro-5-(O-2-acet ic acid)-hydroxy-2-(1-pyrrolidinyl)naphthyl]acetamide (72). Intermediate (.+-.)-65 can be treated with t-butyl bromoacetate and deprotected to produce (.+-.)-2-(3,4-dichlorophenyl)-N-methyl-N-1-[1,2,3,4-tetrahydro-7-(O-2-acet ic acid)-hydroxy-2-(1-pyrrolidinyl)naphthyl]acetamide (73). Intermediate (.+-.)-66 can be treated with methanesulfonyl chloride to produce (.+-.)-2-(3,4-dichlorophenyl)-N-methyl-N-1-[1,2,3,4-tetrahydro-7-(N-methan esulfonamido)-amino-2-(1-pyrrolidinyl)naphthyl]acetamide (74). Intermediate (.+-.)-67 can be treated with methanesulfonyl chloride to produce (.+-.)-2-(3,4-dichlorophenyl)-N-methyl-N-1-[1,2,3,4-tetrahydro-5-(N-methan esulfonamido)-amino-2-(1-pyrrolidinyl)naphthyl]acetamide (75). Intermediate (.+-.)-68 can be treated with glycine benzyl ester and deprotected to produce (.+-.)-2-(3,4-dichlorophenyl)-N-methyl-N-1-[1,2,3,4-tetrahydro-5-(N-2-acet ic acid)-carboxamido-2-(1-pyrrolidinyl)naphthyl]acetamide (76). Intermediate (.+-.)-69 can be treated with glycine benzyl ester and deprotected to produce (.+-.)-2-(3,4-dichlorophenyl)-N-methyl-N-1-[1,2,3,4-tetrahydro-5-(N-2-acet ic acid)-sulfonamido-2-(1-pyrrolidinyl)naphthyl]acetamide (77). Intermediate (.+-.)-70 can be treated with glycine benzyl ester and deprotected to produce (.+-.)-2-(3,4-dichlorophenyl)-N-methyl-N-1-[1,2,3,4-tetrahydro-7-(N-2-acet ic acid)-carboxamido-2-(1-pyrrolidinyl)naphthyl]acetamide (78). Intermediate (.+-.)-71 can be treated with glycine benzyl ester and deprotected to produce (.+-.)-2-(3,4-dichlorophenyl)-N-methyl-N-1-[1,2,3,4-tetrahydro-7-(N-2-acet ic acid)-sulfonamido-2-(1-pyrrolidinyl)naphthyl]acetamide (79). ##STR27## The compounds of formula III of the present invention are prepared by substituting the central phenyl ring with polar groups. ##STR28## Compound 80 and analogues undergo a variety of diazonium-involving reactions for the attachment of polar groups (Scheme 7). ##STR29## Using the procedure shown in Scheme 7, the following compounds are made. Intermediate 81 can be treated with dibenzyl phosphoryl chloride followed by deprotection to produce 2-(3,4-dichlorophenyl)-N-methyl-N-{1-3-(O-phosphoryl)hydroxyphenyl-2-(1-py rrolidinyl)ethyl}acetamide (87). Intermediate 85 can be coupled to methanesulfonyl chloride to produce 2-(3,4-dichlorophenyl)-N-methyl-N-{1-[3-(N-methanesulfonamido)aminomethyl] phenyl-2-(1-pyrrolidinyl)ethyl}acetamide (88). Intermediate 85 can be coupled to 2S-isothiocyanato succinic acid and deprotected to produce 2-(3,4-dichlorophenyl)-N-methyl-N-{1-[3-(N-succinic acid-2S-thioureido)aminomethyl]phenyl-2-(1-pyrrolidinyl)ethyl}acetamide (89). Intermediate 80 can be treated with dibenzyl phosphoryl chloride followed by deprotection to produce 2-(3,4-dichlorophenyl)-N-methyl-N-{1-3-(N-phosphoramido)aminophenyl-2-(1-p yrroldinyl)ethyl}acetamide (90). ##STR30## The compounds of formula IV may be prepared by Scheme 8. ##STR31## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are defined in formulas III and IV. The diamino intermediate 91 (J. Med. Chem. 1990, 33, 286) can be coupled to different regioisomers of nitrophenylacetic acid, which are all commercially available. Reduction of the nitro group provides an amino group for all attachment of polar groups. Alternatively, the amino intermediates 95-97 readily undergo diazonium chemistry that converts the amino groups to carboxyl and sulfonyl chloride groups. This allows the polar groups to be attached via different linkers. Following the procedure in Scheme 8, the following compounds are made. Intermediate 96 can be treated with methanesulfonyl chloride to produce (-)-(5a,7a,8.beta.)-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro-[4,5]dec-8-y l]-3-(N-methanesulfonamido)aminophenylacetamide (104). Intermediate 98 can be coupled to glycine benzyl ester and deprotected to yield (-)-(5a,7a,8.beta.)-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro-[4,5]dec-8-y l]-3-(N-2-acetic acid)sulfonamidophenylacetamide (105). Intermediate 99 can be coupled to glycine benzyl ester and deprotected to yield (-)-(5a,7a,8.beta.)-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro-[4,5]dec-8-y l]-3-(N-2-acetic acid)carboxamidophenylacetamide (106). ##STR32## Compounds of the above formula may have one or more asymmetric carbon atoms. Pure sterochemically isomeric forms of the above compounds may be obtained, and diastereoisomers isolated by physical separation methods, including, but not limited to crystallization and chromatographic methods. Cis and trans diasteriomeric racemates may be further resolved into their isomers. If separated, active isomers may be identified by their activity. Such purification is not, however, necessary for preparation of the compositions or practice of the methods herein. As used herein, the compounds provided herein also include pharmaceutically acceptable salts, acids and esters thereof, stereoisomers, and also metabolites or prodrugs thereof that possess activity as analgesics but do not cause substantial CNS effects when administered or applied. Metabolites include any compound that is produced upon administration of the compound and metabolism thereof. |
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