CA2163095A1 - Treatment process with biologically active tropane derivatives - Google Patents

Abstract

Selective blockade of DA and 5-HT uptake sites with 3-aryltropane derivatives.

Description

W094/26274 ~ ~ 6 3 0 9 5 PCT~S94/03661 Tit:Le: TREATMENT PROCESS WITH BIOLOGICALLY ACTIVE
TROPANE DERIVATIVES

GRANT R~K~C~:
This invention was made with government su~po.
under R01-DA-6301-02 and P50-DA06634 awarded by the Nat~ on~ 1 Institute on Drug Abuse. The government has certain rights in the invention.

8AC~ROUND OF THE lNv~N~lON
The tropane skeleton is a basic structural unit that can lead to compounds with diverse Central Nervous System (CNS) activity. Due to the rigid natl~re of the structure, the possibility exists for the preparation of highly selective ~o...~ounds. This application describes the syntheci~ of tropane derivatives that selectively bind to mo~ 1 ne neu.u~Lansmitters and thus have the potential for the treatment of major depression, Parkinson's ~ Q and attention-deficit hyperactivity disorder (ADD).
Two important central nervous system neu-oL.ansmitters are serotonin (5-HT) and dopamine (DA). Together with norep;neph~ine and epinephrine, these neurotransmitters comprise the group of agents known as the monoamines. Either 5-HT or DA have been implicated in a variety of disorders, including depression, Parkinsons disease, ADD, obesity and co~ addiction.
Major depression represents one of the most .o ~ mental illness, affecting between 5-10~ of the population. The disease is characterized by extreme changes in mood which may also be associated with psychoses. It has generally been found that most W094/26274 PCT~S94/03661 ~63095 2 -ant~pressant agents exert significant effects on the regulation of ~onoA~~ne neuloL ansmitters, including DA, 5-HT and norep~ephrine. The tricyclic antidepressants, such as imipramine, are the most ~ormonly used drugs for the treatment of depression.
Their ab$1ity to ~ nh~ h~ t the neuronal uptake of norep;nephrine is believed to be a ma~or factor behind their efficacy.
A number of new types of antidepressants have been developed in recent years. Two such compounds that are marketed in the U.S. are tr~7o~ne and fluoxetine. Both of these compounds interact with the regulation of S-HT. Tr~oAone potentiates the actions of 5-HT while fluoxetine is a potent and selective ~ nh~ h~ tor of 5-HT reuptake. 3-Chloroimipramine which 1 nh~ h~ ts both 5-HT and norep~n~phrine reuptake has been extensively used as an antidepr~cAnt in Europe and ~n~A. Other compounds which are of ~ e-lt interest or have been examined as ant~pressants include flUVOxAm~ n~, citalopram, zimeldine, bupropion and nomifensine. All of these drugs inhibit mo~oA~ ne uptake mech~n~sms, but differ in selectivity between the dop~n~-, 5-HT and norep~neFhrine tran~o~ers.
Other syndromes also respond to antidepressant drugs. These include (1) severe anxiety syndromes characterized by panic reactions, and (2) obseccive-compulsive disorder, both of which seem most likely to respond to 5-HT selective agents. Monoamine uptake blockers have also been useful in treatment of chronic pain, neuralgias, migraine, sleep apnea, fibromyalgia, and irritable bowel syndrome.
Parkinson's ~;S~Ace effects about 1% of the population over the age of 65 and leads to serious W094l26274 ~ ~ 6 3 0 9 5 PCT~S94/03661 neurological disorders. The main ~l~n~c~l features of the ~lsQ~e are centered around disruption of motor function, such as w~lk~ng~ speech, eating and other skilled acts. It has been recognized that the ~ se is the result of dop~1~e deficiency in the basal ganglia. Thus, drugs that can increase the levels of dopamine have the potential to be effective medications for the treatment of Park~ncon's ~1s~se.
The most effective drug in this regard has been levodopa which acts as a biogenic precursor to dopamine.
Cons~e~able attention has recently been directed to the condition known as attention-deficit hyperactivity disorder. Children with this condition tend to be very active physically but have great difficulty with situations requiring long periods of a~tention. Co~ce~uently, they tend to underachieve academically and can be very disruptive. Furthermore, these behavioral problems often persist in modified forms into adulthood. The condition appears to be ACCO~.~ ated to the effect of monoamines in the cerebral cortex, which are involved with control of attention.
A number of stimulant drugs such as dextroamphet ~ne-, methylphenidate as well as the tricyclic antidepressants, antipsychotic agents and clonidine have been used as medications to control the disorder.
Many of these drugs interact with the monoamine uptake tran~o~Lers.
Another disorder for which inhibitors of monoamine transport are useful therapeutic agents is obesity. In general, sympathomimetic drugs (i.e., those which increase synaptic levels of monoamines) promote weight loss by suppressing appetite. Drugs W094/26274 PCT~S94103661 ~

216309~ 4 like m~n~ol, which act as sympathomimetic agents by blo~k~ng monoamine uptake, have been useful in the treatment of obesity.
C~c~ine has the following formula:

MeN COOCH3 ~COO~>

The basic ring structure of coc~i ne. is a tropane ring xy x l a,-- .
It has previously been shown that coc~ne and related compounds are potent inhibitors of dopamine reuptake and this may lead to ~ ,ounds with reinfo~ n~ properties. In recent years a number of new e~ ~ ly potent coc~ n~ ~n~ 1 ogs have been prepared based on the tropane structure (Abraham et al., Journal of Medtc~nal Chemtstry 1992, 35, 141;
Bo;a et al., European Journal of Phar_acology, 1990, 183,329; Bo;a et al., European Journal of Pharmacology, l99l, 194, 133; Carroll et al., Journal of Med~cinal Chem~-~try, 1992, 35, 969; Carroll et al., JournaL of Med~c~nal Chem~stry, 1992, 35, 1813;
Carroll et al., Journal of Me~ç~n~7 Chem~stry, 1992, 35, 2497, Cline et al., Journal of Pharmacology and Expertmental Therapeut~cs, 1992, 260, 1174; Cline et al., Synapse, 1992 12, 37; Kozikowski et al., Medicinal ~hemistry Research, 1991, 1, 312, Kozikowski et al., Journal of Medic~nal Chem~stry, 1992, 35, 4764; Lewin et al., Journal of Med~c~nal Che~l~try~
1992, 35, 135: Madras et al., Molecular Pharmacology, 1989, 36, 518). All of these compounds are based on the tropane skeleton and tend to selectively bind to 216 ~095 PCT~S94/03661 -the dor~ ne tranx~o,~er. Certain structural variations can lead to compounds that bind with very hi~h selectivity to the dopr ~nQ reuptake site (Carroll et al, Journal of Med~c~nal Chem~st~y, 1992, 35, 2497). However, all of these tropane derivatives are very similar to each other because they are all derived from r,o~n~ as starting material.
It has now been discovered that if the tropane ring ~y~L~- is modified, particularly at the aryl moiety as hereinafter described, compounds can be produced which are more selective in binding to 5-HT
transporters as co~r~ed to DA transporters. Since these modified tropanes (as described below) bind preferentially to the 5-HT transporter, they may preferentially block 5-HT transport, thus, incr~c~ng synaptic levels of 5-HT. This may be helpful in treating ~eAses related to 5-HT function.
Similarly, tropane analogs can be synthesized which selectively block DA tranX~ol~ers and selectively increase synaptic levels of DA.
In principle, the tropane skeleton is l~e~lly suited to prepare highly selective compounds because it is a rigid structure and tropane derivatives will have rather limited conformational flexibility. Such derivatives may be altered by a~plo~liate structural changes so that analogs favoring b~n~ing to either the 5-HT or DA reuptake site could be prepared. The novel ch~m1qtry that has been developed, as referred to in our parent application, has enabled preparation of a much wider range of tropane analogs than was previously ~cc~qible, l~ng to novel structures with selective biological activity.

WOg4/26274 ~ 1 ~ 3 0 ~ 5 PCT~S94/03661 Accordingly, it is a primary ob~ective of the present inventlon to provide a process for preparing tropane analogs which are selective inhibitors of 4 either 5-HT or DA reuptake.
Another primary ob;ective of the present invention is to prepare a range of tropane An~lo~s which can be investigated as drugs for the treatment of chronic depression.
A still further ob;ective of the present invention is to provide a wide range of tropane derivatives which can be systematically used and tested to determine structure-activity relat~o~h~ps for ~n~ng at dopamine, 5-HT and norep~n~ph~ine transporters.
A further objective is to provide a treatment system for diseases whose course can be altered by patient treatment with compounds that selectively bind to either the 5-HT or DA reuptake site and therefore ylevellt neurotrAne~~ ons at this site.

SUMMARY OF THE lN V ~ ~ lON
Biologically active derivatives of the tropane ring ~ys~e-l- are provided which selectively bind either to the 5-HT or DA reuptake site ~ leA~ i n~ to ~o...~unds which have use for treatment of clinical depression, Parkinson's Disease, ADD and obesity.

BRIEF DESCRIPTION OF THE DRAWINGS
Figures l, 2, 3, & 4, show the potencies of various analogs of the present invention 5-HT and DA
in b;n~i ng to transporters. These results demonstrate analogs with three different categories of selectivity: DA-selective, 5-HT selective and non-selective.

PCTIUS94tO3661 DE'rATT-~P DESCRIPTION OF T~EE lNVI~ lON
~ he focus of this application will be on uses of tropane derivatives of the general formula:

Wherein R1 is an aromatic moeity and may be any 1-naphthyl, 2-naphthyl, phenyl, C1 to C8 alkylaryl or indole moiety. Preferred are isopropylphenyl and naphthyl. R2 and R3 may be as follows: Only one of R2 and R3 can be hydrogen at the same time and each of R2 and R3 can be a ketone moiety, (c R ) an Y~ (c-OR2_3) a phosponate, a sulfone moiety, a cyano, an oxazole, or a imidazole. It is preferred that R2 and R3 be selected from ketone moieties or ester moieties, preferably C1 to Cg alkyl or alkoxy. If desired the Me group may be more generally described as R4 which may be hydrogen or lower (C1 to Cg) alkyl.
r~he very most preferred compounds for use in the present process are:
MeN Q~R

H
Wherein R is Cl to Cg and Ar is an aryl moiety as earlier defined.
The synthesis of the tropane derivatives was achieved by the general scheme shown below. The experimental procedure for the final step has been SUBs 11 1 IJTE SHEE~ (RULE 26) W094/26274 PCT~S94/03661 21 ~30~ 5 _ 8 -described in detail in the original patent. The details of the earlier steps have been le~o ~ed (Davies, et al., Journal of O~ganic ~ try, 1991, 56, 5696).

Br COR COR ,~\
RCN ~ SO2N3 N2~ ~/NBOC
,~ Zn ~ NEt3 ,~ Rh2(00ct)~

E ~C l.(PPh3)3RhCl/H2 MeN COR ArMq~r ~ s COR 2.TFA b b~ Oul b~ ~.CH20/Na(CN)BH3 MeN~, + ~,le~ ,OR

Basically, in the process of that case, 3-aryltropane derivatives are prepared by reacting 8-azabicyclo[3.2.1]oct-2-ene with an aryl Grignard reagent in the presence of catalytically effective amounts of copper (I) and/or copper (II) salts. The 3-aryl-tropane derivative starting material can be conveniently prepared by ~e~- ,o~ing function~ ed vinyldiazometh~e~ in the precence of certain pyrroles, preferably in substantial ~e~s of the stoichiometric amount, using a ~ osition catalyst, preferably a rhodium catalyst. The catalyst may also be a copper, palladium or silver salt catalyst. This provides a bicyclic intermediate cont~; n; ng the basic 216 3 09 5 PCT~S94/03661 g tropane ring ~y~L which is thereafter converted to an 8-azabicyclo [3.2.1]oct-2-ene, which ~tself may be used as a starting material to react with an aryl Grignard reagent in providing the synth~cl~ route to the unique coc~ne analogs of the present invention.
The starting material of the process is, namely the 8-azabicyclo[3.2.1]oct-2-ene, and has the following formula:

H3CNb~s,COR

In the above formula R is selected from the group consisting of Cl to C8 alkyl and C, to C8 oxyalkyl. In other words, the two position moiety may be f~nctionally substituted by ketone groups or ester groups.
One of the present inventors, namely Dr. Huw M.
L. Davies, has previously published ~onc~ning the general syn~ c used for the starting material of the parent case, namely synthesizing 8-azabicyclo [3.2.1]oct-2-ene of the above formula. In this regard see, Davies, et al., "Novel Entry to the Tropane System ~y Reaction of Rhodium (II) Acetate Stabilized Vinylcarbenoides with Pyrroles," Tetrahedron Letters, vol. 30, no.35, pp. 4653-4656, (1989) a December 1990 abstract of a regional ACS meeting held in New Orleans, entitled Davies, et al., "Chemistry of Vinylcarbenoids with a Single Electron Withdrawing Group, an Approach to Tropane Alkaloids", American Chemical Society, Dec. 5-7, 1990, pp. 181-182; Davies, et al., "Synthesis of ~ Ferruginine and Anhydro-ecgonine Methyl Ester by a Tandem Cyclopropanation/

PCT~S94/03661 2~3~5 lo-Cope Rearrangement", Journal of Organic Chemistry, 1991, Vol. 56, pp. 5696-5700. The sub~ect matter of each of these publications of Davies et al is incorporated herein by reference and therefore need not be described in full detail. However, certain preferred process operations, not specifically mentioned in the above articles, are described herein for sake of complet~es~.
Preparation of the starting material for the Grignard addition of the present invention, namely, preparation of 8-azabicyclo[3.2.1]oct-2-ene as above described employs in its first step a process of decomposing of a functionAl17ed vinyldiazomethane of the formula:
COR
N2~

in the presence of at least a stoi~-h~o-~tric amount of a pyrrole of the formula:

lCOO~

wherein Z is a functional group protector, and also in the presence of a small but effective amount of a decomposition catalyst selected from the group consisting of rhodium, copper, palladium and silver salts, to provide an intermediate bicyclic compound.

wo g4l26274 ~1 6 3 09~ PCT~S94103661 R as shown above represents a Cl to C8 alkyl or C
to C8 oxyalkyl. Preferably R is an alkyl and therefore as expl A~ neA herein after, the resulting a~alog of cocAine ultimately prepared will have a ketone group at the two position. In the pyrrole, Z
represents a functional group protector such as trimethylsilylethyl, although it is unde ~oo~ that other classic protecting groups such as tertiarybutyl group may also be employed.
The amount of the pyrrole for this first reaction scheme needs to be at least a stoich$ometric amount in comparison with the ~inyldiazomethane and preferably is in excess of the stolchiometric amount, perhaps within the range of a two-fold to a five-fold ~xc~ss.
An ~r~cc iS preferred in terms of achieving the desired high yields of the bicyclic intermediate because the vinyl~i~7omethane is decomroc~ to a very reactive intermediate, namely a vinylcarbenoid which will, unless it is trapped by use of stoichiometric e~ of the pyrrole, rapldly ~
The pyrroles above described can be ~o1.~e,1tion-ally prepared using well known chemistry as described i~ the Journal of Organic Chemistry, l99l, vol. 56 article, of the author earlier cited. ~he reaction is preferably run at a temperature of within the range of from 25C to about 100C, preferably at about 80C.
The reaction can be run at 25C if there is slow addition of the vinyldiazomethane to the pyrrole. The pressure is not critical in this reaction step.
As explained above, the reaction is conducted in the presence of a ~r,omrosition catalyst selected from the group consisting of rhodium, copper, p~ um and silver salts. Preferably the catalyst is a rhodium PCT~S94103661 216309~ 12 -salt catalyst and may be a rhodium (II) a~e~a~e, m~n~ te, trifluoroacetate, he~no~te, pivalate or octanoate. The presently most preferred catalyst is rhodium octanoate which seems to allow h~he~ yields of desired product. The amount of catalyst may vary from 0.25 mole per cent to about 2.0 mole per cent of the vinyl~ o.-thane, and is preferably about l.O
mole per cent of the amount of the vinyl~A7omethane reactant.
Reaction time does not appear to be critical and the time may vary from a few minutes up to several hours if drop wise addition is accompl~hed. The other carbon atoms of the 8-azabicyclo[3.2.1]oct-2-ene can include substituents other than hydrogen (e.g. one or more of the other carbon atoms of the bicyclic ~y~L~ can include a lower alkyl substituent group) because a more highly substituted pyrrole or vinyldiazomethane may be used as starting material.
This first step reaction produces an intermediate bicyclic co...~ound which upon hydrogenating, removal of the de~L~ective group and reductive methylation is ~o-~veL~ed to the earlier described 8-~h~yclo [3.2.1]oct-2-ene. The l,y~Logenation, depL~Le~Ling and reductive methylation are all well known steps and need not be described herein.
Where R equals methyl and the protecting group used is trimethylsilyl the intermediate is methyl 8-(2-(trimethyl-silyl)ethoxycarbonyl)-8-azabicyclo [3.2.1]octa-2,6-dien-2-oate.
This reaction is preferably co~llrted in the presence of a solvent and the solvent is preferably a non-polar solvent. Suitable non-polar solvents for conducting this reaction may be pentane, heY~ne, and W094/26274 PCT~S94/03661 ~6309~

benzene. Other suitable non-polar solvents, cApAhle of dissolving the basic reactants may also be employed, with the precise solvent not being critical, as long as it is in fact non-polar.
For details of the hydrogenating, deprotecting and reductive methylation see, the previously in~oL~ated by reference 1991 vol. 56, Journal of Or~anic Chemistry article. There it is h~c~nAlly described that the catalytic h~dloyenation is a process employing a Wilkinson's catalyst and that dep oLection occurs with, for example, tertiarybutyl ammonium flouride to give the desired 8-azabicyclo [3 2.1]oct-2-ene at yields as high as 95%. As exp~ e~ in the earlier referenced article, the composition is purified by c~l~cA gel column chroma~oyl~hy.
The 8-azabicyclo[3.2.1]oct-2-ene is then used as a starting material for the process of the present invention. It has been found that the 8-azabicyclo [3~2.1]oct-2-ene fo~ earlier described, can be ~onv~l~ed to biologically active ~o~-~1n~ analogs having a wide variety of active analog structures by reacting with a aryl Grignard reagent in the prece of a catalytically effective amount of a copper salt ca~alyst. The copper salt catalyst may be a copper (I) or copper (II) catalyst.
As previously described, it is preferred that the R group of the 8-azabicyclo~3.2.1~oct-2-ene be C1 to C8 al}cyl, rather than an oxyalkyl since it is preferred that the two substituent be a ketone substitution ra~her than an ester substitution. The ketones behave better in the copper catalysed reaction, and as explained later in the biological activity section of PCT~S94/03661 ~16~0~

the specification, should have higher met~hol~c stability and have equivalent h~ n~ ~ ng site activity.
The Grignard addition reaction is run in a suitable non-polar organic solvent, preferably ether or tetrahydrofuran.
The Grignard reagent (ArMgX) may be any sultable aryl magnesium halide. The aryl group may be phenyl, substituted phenyl, C1 to C8 alkylaryl, polyaryl such as naphthyl, anthracyl or alkylpolyaryl. Alkyl ~~esium h~ (C1 to C~) may also be used. The "X"
moiety represents a hAl~e group and is preferably bromide. The copper salt may be a copper (I) or (II) salt and can be, for example, copper bromide dimethyl sulfide. The amount of the Grignard reagent is preferably an ~Ynes~ of the sto~ Ch~ ometric amount $n order to assure completion of the reaction. Suitable high yields are obtA1ne~ when an excess of up to four-fold of the Grignard reagent is employed. The amount of the copper salt catalyst can be from 5% (molar) to 20% (molar) of the Grignard reagent, and is preferably 15 mole percent of the amount of the Grignard reagent.
The reaction to ~lo~e the desired ketone is represented by the following equation reaction:
Me~ ~ ~R Ar~gBr Me O~R Me ~ Cu~rDMS ~+

As seen the reaction product is a mixture of two structural isomers, one with the 2-moiety position upwardly (a) and the second with the 2-moiety position downwardly. (b) Those analogs that are most preferred are the analogs wherein R is alkyl and therefore the W094l26274 PCT~S94/03661 two position moiety is a ketone moiety, and that the structural isomer is with the ketone groups in an up position. These are far more active in b~nA~ng assays, than the downward structural isomers and in some inst~nn~ as much as 200 times more active in site-b~n~ng~
Certain other process conditions are wo ~h~ of mention. The reaction is not temperature critical and may be run at anything from 0C or lower up to room temperature, or even higher. The reaction is preferably run under an inert gas atmosphere. The reaction is substantially immediate and therefore may be run from a few minutes to as much as twelve hours.
Preferably the reaction occurs under stirring in order to assure complet~neRs. After completion the reaction can be qll~n~e~ with for ~mple HCl/ice, with the desired compound extracted with ether. It may be purified as illustrated in the examples by velltional silica gel chromatography.
The ~: , unds may be administered orally, parenterally or intravenously. The preferred route of ~ n~ ctration iS oral. The dose levels may be from 4 micrograms per kilogram of body weight up to 50 mi 1 1; grams/kg of body weight and more typically from 20 micrograms/kg up to 15 mg/kg.
The novel tropane analogs synth~R~ by the vinylcarbeonoid scheme listed above were tested for their ability to interact with 5-HT and dopamine transporters by two assays: displacement of radioligand b;~; ng to transporter sites, and direct inhibition of 5-HT or dopamine uptake in acutely dissociated fetal and adult rat neurons. These assays are known to correlate with transport sites in h~lm~n wo g4l26274 ~
21~ 3 ~ ~ 5 PCT~S94/03661 brain. In bi n~ ~ ng studies, low ~oncentrations (10-20 pM) of [~I~RTI-55, the potent tropane ~nAl~ recently synthesized by Carroll's group (Bo~a et al., European Journal of Pharmaco70gy, 1991, 184, 329), was used to label dopamine tran~ ers in rat striatal membranes, while [~]paroxetine (Harbert et al., European Journal of Pharmacology, 1985, 118, 107) was used to label 5-HT transporter sites in rat frontal cortex. Up to the present time, 34 analogs have been tested for b~n~ng;
their potencies in binding and uptake assays are summarized in Table 1 below.

~163095 ~ ~¦ N 2 o ~o o N ~ o ~ tl o 'U U ~H ~

_ ~ _ N ~_ N _ ~ æ

o f~i¦ _ N N E~ Z 01> _ N ~ ~ æ ~ N

~Y ~ ~ A A 3 ~ N ~ ~ A ~ A ----~ ~ ~ æ ~ æ ~ ~ O ~

e ~ ~ ~ ~ o o ~ ~ N ~ N ~ ~ ~ ~ O -- O N ~ r _ '~_~ N r~ --o T ~I ~ ~~I~~ ~ ~ ~ I ~~ ~~
Q ~ ¦ T C~ ~ c~ T T <,~ T T T T I ~ T I C~ I I T I tJ I T T I I T I T C.:~ I
~n "T ~) _ _ ~ N N N __ N_____~ t~_--T T I C~ t~ C~ T T I T ~ ~ T C~ T C~ ~ C ~ ~ c~

h ~ 7 ~ T ~ ~ ~
t c O _ ~) ~t ID CD 1~ CO 0 ~ 0 ~

SUB~ I I I lJTE SHEET ~RULE 26) W094/26274 PCT~S94/03661 ~30~5 In Table 1, the general formula is that depicted in the earlier part of this application, ~ust at the beg~ nn~ n~ of the h~AA~ ng Detailed Description of the Inventlon. Code names, as presented, WF-l through WF-35, are internal names of the assignee and simply stand for "Wake Forest-l" etc. Two AnAl~gS have been ~s~1~neA trivial abbreviations: WF-ll is PTT, and WF-31 is PIT.
The b~nA~ng affinity of tropane derivatives at the dopamine transporter was the basis of the original patent on drugs for the treatment of ~O~,A ~ n~
addiction. In the original application, the binAlng affinities for WF 1-5, 7-9, 11 were e~ol~ed as background evidence. Since then, a publication with the h~n~in~ affinities for WF 1-5, 7-9, 11, 13, 18, 19, 22, 23, 25 has appeared (Davies, et al., European Journal of Pha~macology - Molecular Pharmacology Sectfon, 1993, 244,93).
Figure 1 l_- rAreS the disp~ ? t of [~I]RTI-55 h~ n~ ng by cocaine with four tropane analogs, PTT, PIT, WF-23, and WF-33. This leads to information on how these compounds bind to the dopamine tran~o Ler.
These data showed that the two 2-naphthyl analogs, WF-23 and WF-33, were the most potent of these compounds, followed by PTT. PIT, in contrast, was less potent in displacing [~I]RTI-55 than cocA~ne. Comparison of IC~ values (Table 1) showed that WF-23 and WF-33 were 900 to 1300 times, while PTT was 20 times, more potent than co~Aine in b;nAi ng to dopAr;ne transporters. In contrast, PIT was 2.5 times less potent than coc~ine at dopAr~ne transporters.
Figure 2 shows how the selectivities of these analogs were determined in [~]paroxetine binA~ng PCT~S94/03661 ~16309~

experiments. This leads to information on how these ~ ounds bind to the 5-HT trans~ ~er. Agaln, the 2-naphthyl analogs, WF-23 and WF-33, were the most po~ent compounds in disp~ n~ ~3H]paroxetine b~n~1n~, as they were vs. [~I]RTI-55 b1nA~n~ (Fig. l).
However, whereas these An~1ogs were equipotent in displacing ~ I]RTI-55 h~ n~ ng, WF-33 was 4 times less potent than WF-23 in disp1~n~ ~H]paroxetine h~nA~ng, Furthermore, the two phenyl AnA1o~s, PTT and PIT, exchanged places in diSplA~n~ ~3H]paroxetine comrA~ed to [~I]RTI-55: PIT was significantly more potent in disp1~ ~g t3H]~a~ae~ine than co~A~ne~
whlle PTT was a~lo~imately equipotent with cocaine in displacing ~3H]paroxetine h~nA~ng (Fig. 2). IC~ values (Table 1) showed that WF-23 and WF-33 were 480 times and 140 times, respectively, more potent than ~o~ ne at 5-HT tran~olLer sites, while PIT was 8 times more po~ent than COCA ~ n~ and PTT was twice as potent as cocaine. Table ~ shows the potency ratios of all analogs in b~nA~ng assays dopamine and 5-HT
transporters (higher numbers demonstrate relatively greater dopr ~ne tran~ Lel ~vLelloy). These data su~gested that PIT was relatively selective for 5-HT
transporters, while PTT and PIT were relatively more selective for dopamine tran~ Lers. In contrast, WF-23 was like ~o~ n~, with little selectivity between the two tran~po Lers. However, it was 500-800 times more potent than co~1 ne at both tran~ol~e The synthetic scheme that was used to produce tropane analogs from vinylcarbenoid precu~ ~Gl ~
generated racemic compounds; therefore, all the binding studies discussed above were conducted with racemic compounds. When WF-23 was separated into two W094/26274 PCT~S94/03661 ~63~g~

stereoisomers by a chiral HPLC column, the active isomer displayed an est1mated IC~value of 0.03 nM vs.
[~I]RTI-55, while the inactive isomer demonstrated an IC~value of 113 nM (see values for WF-23(1) and WF-23(2) in Table 1). These results not only demonstrated that ~Le eoisomers can be separated by the chiral HPLC, but also shows that the active lsomer is extremely potent. The active isomer of WF-23 was also potent vs. [~3paroxetine b~n~n~, and the selectivity of the active and inactive isomers were the same as the racemic mixture of WF-23. Generally those isomers with R2 in the up position were more active, and as well, those compounds where R2 was a ke~one were more active.
Uptake studies have been con~l~cted on ~ev~ al selected analogs to confirm the results of the b1 n~ ~ ng studies. These experiments ut~ A ~ ~ ~co~.~ Ated cells ~
from fetal and adult rat brain, using the striatum for dopamine uptake assays, and the frontal ~G~ Lex for 5-HT uptake assays. Fig. 3 shows the inhibition of [3H]dop~1ne uptake into striatal cells by cocaine and selected tropane ~Alogs. These results were comparable to the b~nA~ng assays: while WF-23 was the most potent analog in inhibiting dop~ uptake followed by WF-ll, WF-31 was considerably less potent in blocking [3H]dopamine uptake. Experiments with [~]5-HT uptake in cortical cells (Fig. 4) also SU~Ol ~ed the results of the b~nAi~g assays, showing that WF-23 and WF-31 were both significantly more potent than cocaine in blocking tH]5-HT uptake. Thus the uptake assays confirmed the selectivities of these tropane analogs as determined in b; n~ ~ ng assays. For example, WF-11 was 140 times more potent in inhibiting ~ W094/26274 PCT~S94/03661 2~3Qg5 dopamine uptake than 5-HT uptake, while WF-31 was 120 tlmes more potent in ~ nh~ h~ ting 5-HT uptake than dopamine uptake, both somewhat greater than the ratios detel ~ne~ by h~ ng studies (Table 1). In contrast, WF-23, whether assayed as a racemic mixture or as its active stereoisomer, provided a dopamine: 5-HT ratio of only 3-4 regardless of the assay used.
In addition to the iso~u~ylphenyl derivative WF-31v it is also clear that the ethylphenyl der$vative WF--9, and the 1-(4-methylnapthyl) der$vative WF-27 also display considerable selectivity towards the 5-HT
tranx~olLer in terms of h~ ng and inhibition. The co~mon feature of these derivatives is that they contain a funct~ O~A lity that may lie to some extent in the ~el~endicular plane to the aromatic ring. This stru~Lulal variation leads to a novel type of biological activity for compounds in the tropane series with potential for the development of a novel class of antidepressant drugs. The general activity of the group of analogs at monoamine transporter sites strates that they have potential for the treatment of other diseases associated with monoamine imbAl~eR such as Parkinson's Disease, attention-deficit hyperactivity disorder, and obesity.

Claims (16)

WHAT IS CLAIMED IS:

1. A method of treating mammals to selectively block 5-HT uptake, said method comprising: administering a small but 5-HT blocking effective amount of a3-aryltropane derivative of the formula:

and structural isomers thereof, wherein R1 is an aromatic ring moiety selected from the group consisting of 1-naphthyl, 2-naphthyl, phenyl, C1 to C8 alkylaryl, and indole; and R2 and R3 may be the same of different and are selected from the group consisting of hydrogen, C1 to C8 ketones, with only one of R2 and R3 beinghydrogen at any one time and R4 is methyl, hydrogen or lower alkyl.

2. The method of claim 1 where R2 is a ketone.

3. The method of claim 1 wherein R2 is a beta-isomer.

4. A method of treating mammals to selectively block 5-HT uptake, said method comprising administering a small but 5-HT effective blocking amount of a 3-aryltropane derivative of the formula:

and structural isomers thereof wherein R equals C1 to C8 alkyl and Ar is an aromatic ring moiety, to said mammals.

5. The method of claim 1 wherein the mammal is the human species.

6. The method of claim 2 wherein the administration is by a method selected from the group of oral, intravenous, and parenteral.

7. The method of claim 2 wherein the 3-aryltropane derivative is administered at a dose level of from 1 micrograms/Kg to 50 milligrams Kg.

8. The method of claim 2 wherein the aryltropane derivative is administered orally at a dose level from 20 micrograms/Kg to 15 mg/Kg.

9. A method of treating mammals to selectively block Dopamine uptake, said method comprising administering a small but dopamine uptake blocking effective amount of a 3-aryltropane derivative of the formula:

and structural isomers thereof, wherein R1 is an aromatic ring moiety selected from the group consisting of 1-naphthyl, 2-naphthyl, phenyl, C1 to C8 alkylaryl, and indole; and R2 and R3 may be the same or different and are selected from the group consisting of hydrogen, C1 to C8 ketones, with only on of R2 and R3 being hydrogen at any one tie and R4 is methyl, hydrogen or lower alkyl.

10. The method of claim 9 wherein R2 is a ketone.

11. The method of claim 9 wherein R2 is an isomer with R2 in the beta-position.

12. A method of treating mammals to selectively block 5-HT uptake, said method comprising administering a small but 5-HT blocking effective amount of a 3-aryltropane derivative of the formula:

and structural isomers thereof wherein R equals C1 to C8 alkyl and Ar is an aromatic ring moiety, to said mammals.

13. The method of claim 9 wherein the mammal is the human species.

14. The method of claim 10 wherein the administration is by a method selected from the group of oral, intravenous, and parenteral.

15. The method of claim 10 wherein the 3-aryltropane derivative is administered at a dose level of from 1 microgram/Kg to 50 milligrams/Kg.

16. The method of claim 10 wherein the 3-aryltropane derivative is administered orally at a dose level of from 20 micrograms/Kg to 15 mg/Kg.