WO1991000727A1

WO1991000727A1 - Substituted 2-aminotetralins

Info

Publication number: WO1991000727A1
Application number: PCT/US1990/003761
Authority: WO
Inventors: James V. Peck; Gevork Minaskanian
Original assignee: Whitby Research Inc
Current assignee: Whitby Research Inc
Priority date: 1989-07-05
Filing date: 1990-07-02
Publication date: 1991-01-24
Anticipated expiration: 1992-01-05
Also published as: EP0463119A1; AU6072090A; CA2065450A1; EP0463119A4

Abstract

Optically active or racemic compounds are provided having formula (I). Wherein the radicals R1, R2, R3, R4, R6, X and N are defined in the specification. These compounds are optically active or racemic mixtures capable of binding selectively one or more dopamine D2 receptors, for instance in humans. They are useful in treatment of disorders of the central nervous, cardiovascular, and endocrine systems such as elevated intraocular pressure, schizophrenia and parkinsonism, and for inducing anorexia and weight loss in humans and other mammals.

Description

SUBSTITUTED 2-AMINOTETRALINS

Background of the Invention

Field of the Invention

The invention relates generally to substituted 2-aminotetralins and to processes for preparing such compounds. More particularly, the invention relates to compounds for therapeutic use, in particular in treating disorders of the central nervous, cardiovascular and endocrine systems. The compounds of this invention are also useful for alleviating glaucoma, parkinsonism, and schizophrenia, and for inducing anorexia and weight loss in mammals.

Background of the Prior Art

It is known that various hydroxylated 2-aminotetralins of the general formula

where R₁ and R₂ are saturated alkyl groups and n is 1 or 2 , are dopamine receptor agonists (McDermed et al., J. Med. Chem. 18 , 362 (1975); Feenstra et al., Arch. Pharmacol. 313, 213 (1980). Many structure-activity relationship studies have been conducted to find compounds with high dopamine-receptor stimulating activity. A survey is contained in Katerinopoulos, H. E., et al., "Structure-Activity Relationships for Dopamine Analogues," Drugs of the Future. Vol. 12, No. 3, 1987, 223-253. Based upon the high activity of apomorphine, many derivatives and simplified structural analogues have been tested and found to have dopaminergic activity. For instance, some of the bicyclic analogues of dopamine, 2-amino-5,6- and 2-amino-6,7-dihydroxytetralin, and their N-alkylated derivatives were tested and showed activity.

In addition, studies have shown that the 5-hydroxy derivatives of 2-aminotetralins possess high potency almost equivalent to that of the 5,6 catechols, with the additional advantage of increased stability, selectivity and duration of biochemical action. These studies have also shown that in bicyclic compounds the size of the- two nitrogen substituents controls activity. For instance, the N-butyl and N,N-dibutyl derivatives of 2-amino-5,6-dihydroxytetralin, dopamine and norapomorphine have little or no dopaminergic activity, while analogues having at least one N-ethyl or N-n-propyl group possess high activity.

Further studies have shown that the D₂ receptor potency of dopamine agonists is at a maximum when one of the two N-substituents fits into a receptor niche which, because of size constraints maximally accommodates an n-propyl group Conversely, activity drops off when the propyl group is replaced by the smaller groups ethyl or methyl. When the compound contains no N-substituent at least as small as n-propyl, activity is small or non-existent.

However, the structural requirements for the second N-substituent in such compounds have not been established-Consequently, the search continues for new and better N-substituents to enhance both dopamine receptor binding and activity, especially as shown by in vivo studies designed to test the dopaminergic activity of compounds, such as contralateral turning studies in 6-OH-DA-lesioned rats. See Seiler, Max P., et al., "Structure-Activity Relationships of Dopaminergic 5-Hydroxy-2-aminotetralin Derivatives with Functionalized N-Alkyl Substituents." J. Med. Chem. 1986, 29, 912-917.

The receptor site into which this second N-substituent is thought to interact appears to accommodate a wide variety of large, bulky groups having different functionalities without loss of activity. See McDermed, J. D., et al., J. Med. Chem. 1975, 18, 362; Cannon, J. G., et al., J. Med. Chem. 1977, 20, 1111; and Wikstroem, H., et al., J. Med. Chem. 1982, 25, 925. However, the dopaminergic activity and potency conferred upon the compound by the choice of the second N-substituent is at present, unpredictable so that the search continues for new and better dopamine receptor agonists, especially for compounds showing a high degree of selectivity and specificity as either D₁ or D₂ receptor agonists. Summary of the Invention

There has now been discovered certain novel compounds having dopaminergic activity and having the structural formula

where R₂, R₃ and R₄ are each selected from the group consisting of H and OA with the provision that at least one of R₂, R₃ and R₄ is H, that R₂ and R₄ are not both OA; A is H or is selected from the group consisting of hydrocarbyl radicals, for example lower alkyl radicals optionally substituted with aromatic residues (i.e. methyl, ethyl, propyl, benzyl, etc.), as well as and

R₅ is selected from the group consisting of alkyl and aromatic residues having between 1 and 12, preferably between 1 and 6, carbon atoms, for example alkyl, optionally subεtitued with aromatic residues, and aromatic residues optionally substituted with alkyl radicals; n is an integer between 1 and 4; R₆ is an alkyl chain comprising between 1 and 4 carbon atoms, X is selected from the group consisting of -CH₂-, oxygen, sulfur, and nitrogen, with the provision that when X is not -CH₂-, R₁ is selected from the group consisting of

wherein Z is oxygen, nitrogen or sulfur, wherein Y is selected from the group consisting of hydroxy, nitro, cyano, azido, amino, acylamino, carbpxyamido, trifluoromethyl, sulfate, sulfonamido, halogen, hydrocarbyl, and hetero atom-substituted hydrocarbyl radicals, wherein said heteroatoms are selected from the group consisting of halogen, nitrogen, oxygen, sulfur and phosphorus and said hydrocarbyl radicals comprise from 1 to 12 carbon atoms, and a is an integer of from zero to 3; and with the further provision that when X is -CH₂-, R₁ is either or

wherein R₈ is hydrogen, aryl, or R ₆; and further wherein R₉ is aryl, R_6' -OH, -NH₂, -OR₆, or -N(R₆)₂; or R₁ is

wherein B is oxygen, sulfur or two hydrogen atoms, and pharmaceutically acceptable salts thereof.

Preferably, R₂ is OA and A is H.

It is essential that the compounds in the present invention be an optically active compound or racemic mixture thereof having substantial affinity and selectivity for binding to dopamine D₂ receptors, e.g., in a human. In particular, it is found that 2-(N-n-propyl,N-2-[phenyloxy]ethylamino)-5-hydroxytetralin is especially preferred for its high affinity and selectivity for binding to dopamine D₂ receptors.

Detailed Description of the Invention The compounds used in the present invention are selected from the group of steroisomers or mixtures thereof of compounds having dopaminergic activity represented by the formula:

where R₂, R₃ and R₄ are each selected from the group consisting of H and OA with the provision that at least one of R₂ R₃ and R₄ is H, that R₂ and R₄ are not both OA; A is H or is selected from the group consisting of hydrocarbyl radicals, for example lower alkyl radicals, optionally substituted with aromatic residues (i.e. methyl, ethyl, propyl, benzyl, etc.),

R ₅ is selected from the group consisting of alkyl and a tic residues having between 1 and 12, preferably between 1 and 6, carbon atoms, for example alkyl residues optionally substituted with aromatic residues and aromatic residues optionally substituted with alkyl radicals; n is an integer between 1 or 4; R₆ is an alkyl chain comprising between 1 and 4 carbon atoms; X is selected from the group consisting of -CH₂-, oxygen, sulfur, and nitrogen, with the provision that when X is not -CH₂-, R is selected from the group consisting of

wherein Z is oxygen, nitrogen or sulfur, wherein Y is selected from the group consisting of hydroxy, nitro, cyano, azido, amino, acylamino, carboxyamido, trifluoromethyl, sulfate, sulfonamido, halogen, hydrocarbyl and hetero atom-substituted hydrocarbyl radicals, wherein said heteroatoms are selected from the group consisting of halogen, nitrogen, oxygen, sulfur and phosphorus and said hydrocarbyl radicals comprise from 1 to 12, preferably 1 to 6, carbon atoms, and a is an integer of from zero to 3, for instance zero to 2; and with the further provision that when X is -CH₂-, R₁ is either

wherein R₈ is hydrogen, aryl, or R₆;; and further wherein R₉ is aryl, R₆, -OH, -NH_2, -OR₆, or -N(R₆)₂;

or R₁ is

Preferably, R₂ is OA and A is H.

A is preferably H or is selected from the group consisting of phenyl and alkyl radicals having from 1 to 12 carbon atoms, and more preferably R₅ is an alkyl or aryl radical that would serve to extend the activity of the compound in the body, for example phenyl, methyl, t-butyl, o-methylphenyl, o-, m- or p-methoxyphenyl, p-isopropylphenyl or nonyl.

The more preferred groups represented by R are thienyl, phenyl, hydroxyphenyl, furanyl and naphthalenyl, e.g., 2-thienyl, 3-thienyl, 3 -hydroxyphenyl, 4-hydroxyphenyl, etc.

In the more preferred compounds for use in the present invention n is 2, X is oxygen or -CH₂- and R₂ is OA; and most preferably A is H and R₆ is propyl. It is essential that the compounds herein be an optically active or racemic mixtures capable of binding selectively to one or more dopamine D₂ receptors, e.g., in a human. In particular, 2-(N-n-propyl,N-2-[phenyloxy] ethylamino)-5-hydroxytetralin is an especially preferred compound because of its high affinity and selectivity for binding to D₂ dopamine receptors. Due to their high affinity for binding to D₂ dopamine receptors, it is believed that the compounds herein will be useful in the treatment of disorders of the central nervous, cardiovascular, and endocrine systems. In particular it is believed that the compounds herein are useful in the treatment of such conditions in humans as elevated intraocular pressure, schizophrenia and parkinsonism, and for inducing anorexia and weight loss in humans and other mammals.

Particularly preferred compounds are as follows:

Compounds wherein X is oxygen, nitrogen or sulfur and R₁ is selected from the group consisting of radicals represented by the general formula:

wherein specific preferred compounds of this group include:

2-(N-n-propyl-N-2-[2-thienyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[3-thienyloxy]ethylamino)-5-hydroxtetralin,

2-(N-n-propyl-N-2-[2-furanyloxy]ethylamino)-5-hydroxytetralin, 2-(N-n-propyl-N-2-[3-furanyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[2-(4-methyl)thienyloxy]ethylamino-5-hydroxytetralin,

2-(N-n-propyl-N-2-[2-(3,4,5-trimethy1)thienyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[2-(5-chloro)thienyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[2-(4-bromo-5-methyl)thienyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[2-(4-methyl-5-ethyl)thienyloxy]ethylamino)-5-hydroxytetralin,

Compounds wherein X is oxygen, nitrogen or sulfur and wherein R₁ is selected from the group of radicals represented by the formulae:

More preferably, in these compounds Y comprises no more than 5 carbon atoms and a is an integer from 0 to 2. Specific preferred compounds of this group include:

2-(N-n-propyl-N-2-[2-naphthalenyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[4-indolyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[2-benzothienyloxy]ethylamino)-5-hydroxytetralin, and

2-(N-n-propyl-N-2-[3-benzothienyloxy]ethylamino)-5-hydroxytetralin; Compounds wherein R₁ is phenyl and/or substituted phenyl and is selected from the group of radicals represented by the formula:

and wherein X is oxygen, nitrogen or sulfur. Specific preferred compounds of this group include:

2-(N-n-propyl-N-2-[phenyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[4-hydroxyphenyloxy]ethylamino)-5-hydroxytetralin, and

2-(N-n-propyl-N-2-[3-hydroxyphenyloxy]ethylamino)-5-hydroxytetralin,

2-(N-n-propyl-N-2-[phenyloxy]ethylamino)-5-methoxytetralin

2-(N-n-propyl-N-2-[phenylamino]ethylamino)-5-hydroxytetralin

2-(N-n-propyl-N-2-[4-hydroxyphenylamino]ethylamino)-5-hydroxytetralin

2-(N-n-propyl-N-3-[phenyloxy]propylamino)-5-hydroxytetra1in

2-(N-n-propyl-N-2-[2,6-dimethylphenyloxy]ethylamino)-5-hydroxytetralin

2-(N-n-propyl-N-2-[3,5-dimethylphenyloxy)ethylamino)-5-hydroxytetralin

Compounds wherein X is -CH2- and R1 is selected from the group consisting of radicals represented by the following formulae:

and wherein B is O, S, or H₂. Specific preferred compounds in this group include:

3-[2-[propyl(1,2,3,4-tetrahydro-5-methoxy-2-naphthalenyl)amino]ethyl]-1(3H)-isobenzofuranone

3-[2-[propyl(1,2,3,4-tetrahydro-5-hydroxy-2-naphthalenyl)amino]ethyl]-1(3H)-isobenzofuranone

6- [2-(1,3-dihydro-1-isobenzofuranyl)ethyl]propylamino]-5,6,7,8-tetrahydro-1-naphthalenol

2-(N-n-propyl-N-3,3,3-triphenylpropylamino)-5-hydroxytetralin

2-(N-n-propyl-N-2,2,2-triphenylethylamino)-5-hydroxytetralin

2-(N-n-propyl-N-3,3-diphenylpropylamino)-5-hydroxytetralin

2-(N-n-propyl-N-2,2-diphenylethylamino)-5-hydroxytetralin

2-(N-n-propyl-N-2-phenylpropylamino)-5-hydroxytetralin 2-(N-n-propyl-N-2-phenylpropylamino)-5-methoxytetralin 2-(N-n-propyl-N-2-(-2-methoxy)phenethylamino)-5-hydrσxytetralin

2-[N-n-propyl-N-2-(2-phenyloxy)propylamino]-5-hydroxytetralin

The invention is further illustrated by the following examples which are illustrative of various aspects of the invention, and are not intended as limiting the scope of the inventions defined by the appended claims. EXAMPLE 1

Preparation of 2-[N-n-propyl,N-2-(phenyloxy)ethylamino]-5-methoxytetralin.

A mixture of 2- (N-n-propylamino)-5-methoxytetralin (7.0 g, 0.0319 mol; prepared according to J. Chem. Soc., 1965, pp 26-36), phenoxyacetic acid (4.86 g, 0.0319 mol), and borane trimethylamine complex (2.33 g, 0.0319 mol) was refluxed in xylenes overnight. The cooled reaction mixture was extracted with NaHCO₃ and the organic layer was dried over MgS0₄, filtered and concentrated under reduced pressure. The resulting oil was subjected to flash chromatography (silica; 9:1 pet ether/EtOAc) and product was isolated: NMR of the free base (300 MHz, CDCl₃): S 7.3-6.6 (m, 8H), 4.0(t, 2H), 3.7(s, 3H), 3.1-2.5 (m, 9H) , 2.1(m, 1H), 1.7-1.4 (m, 3H), 0.9(t, 3H). The free base thus isolated was converted to a hydrochloride salt by the addition of dry ether-HCl.

EXAMPLE 2

Preparation of 2-[N-n-propyl,N-2-(phenyloxy)ethylamino]-5-hydroxytetralin.

A mixture of pyridine hydrochloride and the product of Example 1 was heated in an oil bath at 200°C. When the reaction was complete (TLC), it was cooled, diluted with H₂O, made basic with NH₄OH and extracted with ether. The organic layer was dried over MgSO₄, filtered and concentrated under reduced pressure. The residue was subjected to flash chromatography (silico: C.E. pet ether/EtOAc). The product was dissolved in ether and converted to a hydrochloride salt by the addtition of dry ether-HCl. Anal. Calcd. for C₂₁H₂₇NO₂.HCl: C, 69.69; H, 7.80; N, 3.87. Found: C, 69.54; H, 7.90; N, 3.87. NMR of the free base (300 MHz, CDCl₃) : δ 7.3-6.6(m, 8H), 4.0(t, 2H), 3.1-2.5 (m, 9H), 2.1(m, 1H), 1.7-1.4 (in, 3H) , 0.9(t, 3H).

EXAMPLE 3

The product of Example 2 was also obtained by dissolving the product of Example 1 in dry dichloromethane and adding a solution of boron tribromide in dichloromethane dropwise at room temperture under nitrogen. After completion, the reaction was poured into a beaker containing NH₄OH and ice and stirred for 0.5 h. The organic layer was separated, and the product was purified as in Example 2.

EXAMPLE 4

Preparation of 2-[N-n-propyl,N-3-(phenyloxy)propylamino]-5-methoxytetralin.

In Example 1, phenoxyacetic acid can be replaced by 3-phenoxy-propionic acid.

EXAMPLE 5

Preparation of 2-[N-n-propyl,N-3-(phenyloxy)propylamino]-5-hydroxytetralin.

The product of Example 4 can be used as the starting material for Example 2. EXAMPLE 6

Preparation of 2-[N-n-propyl,N-2-(1-naphthalenyloxy) ethylamino]-5-methoxytetralin.

In Example 1, phenoxyacetic acid was replaced by (1-naphthoxy)-acetic acid. The resulting oil was sujbected to flash chromatography (silica; pet ether) and the product was isolated; characteristic peak of NMR (300 MHz, CDCl₃); δ 8.3-6.7 (m,10H), 4.2(m, 2H), 3.85(s, 3H), 1.0(t, 3H).

EXAMPLE 7

Preparation of 2-[N-n-propyl,N-3-(1-naphthalenyloxy) propylamino]-5-hydroxytetralin.

The product of Example 6 was used as the starting material in Example 2. The resulting oil was subjected to flash chromatography and the isolated product showed characteristic peaks at : NMR (CDCl₃) δ 8.3-6.6 (m, 10H), 4.2(m, 2H), 0.9(t,3H).

EXAMPLE 8

Preparation of 3-[2-[propyl(1,2,3,4-tetrahydro-5-methoxy-2- naphthalenyl)amino]ethyl]-1(3H)-isobenzofuranone.

In Example 1, phenoxyacetic acid was replaced by phthalide-3-acetic acid. The resulting oil was subjected to flash chromatography and the isolated product showed distinct peaks at: NMR (CDCl₃) δ 8.0-6.7(m, 7H) , 5.7(m, 1H), 3.8(s, 3H), 0.9 (t, 3H). Anal. Calc. for C₂₄H₂₉NO₃ HCl: C, 69.00, N, 7.27, N, 3.37. Found: C, 69. OS; H, 7.23; N, 3.28. EXAMPLE 9

Preparation of 3-[2-[propyl(1,2,3,4-tetrahydro-5-hydroxy-2-naphthalenyl)amino]ethyl]-1(3H)-isobenzofuranone.

The product of Example 8 was used as the starting material for Example 3. The resulting oil after purification showed distinct peaks at: NMR(CDC1₃) δ 7.9-6.6(m, 7H), 5.7(m, 1H), 0.95(t, 3H). Anal. Calc. for C₂₃H₂₇NO₃ . HCl: C, 68.73; H, 7.02; N, 3.48. Found: C, 68.62; H, 7.09; N, 3.35.

EXAMPLE 10

Preparation of 6-[[2-(1,3-dihydro-1-isobenzofuranyl) ethyl]propylamino]-5,6,7,8-tetrahydro-1-naphthalenol.

The reduction of the product of Example 9 will result in the desired product.

EXAMPLE 11

Preparation of 2-[N-n-propyl,N-2,2-diphenylethylamino)-5-methoxytetralin.

In Example 1, phenoxyacetic acid was replaced by diphenylactic acid. The purified product showed characteristic peaks at: NMR(CDCl₃) δ 7.8-6.65(m, 13H), 4.1(t, 1H), 3.8(s, 3H), 3.2(d, 2H), 0.7(t, 3H).

EXAMPLE 12

Preparation of 2-[N-n-propyl,N-2,2-diphenylethylamino]-5-hydroxytetralin. The product of Example 11 was used as starting material in Example 3. After purification the product showed distinct peaks at: NMR(CDCl₃) δ 7.8-6.65(m, 13H), 4.1(t, 1H), 3.2 (d, 2H), 0.7(t, 3H). Anal. calc. for C₂₇H₃₁NO . HCl: C, 76.84; H, 7.64; N, 3.32. Observed: C, 77.00; H, 7.69; N, 3.21.

EXAMPLE 13

Preparation of 2-[N-n-propyl,N-3,3-diphenylpropylamino]-5-methoxytetralin.

In Example 1, phenoxyacetic acid was replaced by 3,3-diphenylpropionic acid. The purified product showed distinct peaks at: NMR(CDCl₃) δ 7.4-7.2 (m, 11H), 6.65(m, 2H), 4.05(t,lH), 3.8(s, 3H), 0.9(s, 3H).

EXAMPLE 14

Preparation of 2-[N-n-propyl,N-3,3-diphenylpropylamino]-5-hydroxytetralin.

The product of Example 13 was used as starting material for Example 3. The isolated product showed distinct peaks at: NMR(CDCl₃) δ 7.4-7.0(m, 1H) , 6.7-6.5(m, 2H), 4.0(t, 1H), 0.9(t, 3H).

EXAMPLE 15

Preparation of 2-[N-n-propyl,N-2-(2-phenyloxy)propylamino]-5-methoxytetralin.

In Example 1, phenoxyacetic acid was replaced by DL-2-phenoxypropionic acid. The purified product showed distinct peaks at: NMR(CDCl₃) δ 7.3-6.65 (m, 8H) , 4.45(m, 1H), 3.8(S, 3H) , 0.9(t, 3H) .

EXAMPLE 16

Preparation of 2-[N-n-propyl,N-2-(2-phenyloxy)propylamino]-5-hydroxytetralin.

The product of Example 15 was used as starting material for Example 2. The isolated product showed characteristic peaks at: NMR(CDCl₃) δ 7.3-6.65(m, 8H) , 4.45(m, 1H), 0.9 (t, 3H). EXAMPLE 17

Preparation of 2-[N-n-propyl,N-3,3,3-triphenylpropylamino]-5-methoxytetralin.

In Example 1, phenoxyacetic acid was replaced by 3,3,3-lriphenylpropionic acid. The purified product showed characteristic peaks at : NMR(CDCl₃) δ 7.4-6.65(m, 18H), 3.8(s, 3H), 0.9(t, 3H). EXAMPLE 18

Preparation of 2-[N-n-propyl,N-3,3,3-triphenylpropylamino]-5-hydroxytetralin.

The product of Example 17 was used as starting material in Example 3. After purification the product showed distinct peaks at: NMR(CDCl₃) δ 7.4-6.65(m, 18H), 0.9(t, 3H).

EXAMPLE 19

Preparation of 2-[N-n-propyl,N-2,2,2-triphenylethylamino]-5-methoxytetralin.

In Example 1, pehnoxyacetic acid can be replaced by triphenylacetic acid.

EXAMPLE 20-Preparation of 2-[N-n-propyl,N-2,2,2-triphenylethylamino]5-hydroxytetralin.

The product of Example 19 can be used as the starting material for Example 3.

EXAMPLE 21

Preparation of 2-[N-n-propyl,N-2-[2-methoxy]phenethyl-amino]-5-methoxytetralin.

In Example 1, phenoxyacetic acid can be replaced by α-methoxyphenlyacetic acid. EXAMPLE 22

Preparation of 2-[N-n-propyl,N-2-(2-methoxy)phenethyl-amino]-5-hyroxytetralin.

The product of Example 21 can be used as the starting material for Example 2.

EXAMPLE 23

Preparation of 2-[N-n-propyl,N-(2,3-dihydro-1H-inden-1-yl)methylamino]-5-methoxytetralin.

In Example 1, phenoxyactic acid can be replaced by 1-indancarboxylic acid.

EXAMPLE 24

Preparation of 2-[N-n-propyl,N-(2,3-dihydro-1H-inden-1- yl)methylamino]-5-hydroxytetralin.

The product of Example 23 can be used as the starting material for Example 3.

EXAMPLE 25

Preparation of 2-[N-n-propyl,N-(tetrahydro-2-naphthyl) methylamino]-5-methoxytetralin.

In Example 1, phenoxyacetic acid can be replaced by 1,2,3,4-tetrahydro-2-naphthoic acid. EXAMPLE 26

Preparation of 2-[N-n-propyl,N-(tetrahydro-2-naphthyl) methylamino]-5-hydroxytetralin.

The product of Example 25 can be used as the starting material for Example 3.

EXAMPLE 27

Preparation of 2-[N-n-propyl,N-2-(3,5-dimethylphenyloxy) ethylamino]-5-methoxytetralin.

In Example 1, phenoxyacetic acid can be replaced by 3,5-dimethylphenoxyacetic acid.

EXAMPLE 28

Preparation of 2-[N-n-propyl,N-2-(3,5-dimethylphenyloxy) ethylamino]-5-hydroxytetralin.

The product of Example 27 can be used as the starting material for Example 3.

EXAMPLE 29

To test the selectivity and specificity of the present compounds for binding to dopamine receptors tests were conducted using the following standard procedures.

To test binding to dopamine receptors, the bovine caudate nuclei assay was employed. Bovine brains were obtained fresh from a local slaughterhouse. The caudate nuclei were dissected out and homogenized in Buffer A (50 mM Tris; 1 mM Na₂-EDTA; 5 mM KCl; 1 mM MgCl₂ ; 2 mM CaCl₂; pH 7.4) using a Brinkman Polytron. The homogenate was centrifuged at 40,000 × g for 20 minutes and washed once. The pellett was resuspended in Buffer A, incubated at 37°C for 15 minutes, then centrifuged. The pellet was washed once more, resuspended to a protein concentration of 5-10 mg/ml in Buffer A and frozen at -70°C until used.

To test binding of the compounds to α₂-adrenergic receptors, the rat cerebral cortex assay was employed. Male Sprague Dawley rats were killed by decapitation and the brains removed. The cerebral cortices were homogenized in 50 mM Tris; 2mM MgCl₂ (pH 7.4), and centrifuged at 40,000 × g for 10 minutes. The pellet was washed once, resuspended in Tris/MgCl₂ and incubated with 8 units/ml adenosine deaminase at 37 °C for 30 minutes. The homogenate was centrifuged, washed once, resuspended to a protein concentration of 5-10 mg/ml and frozen at -70°C until use.

The following tritiated drugs were used as radioligands for each of the receptors tested: [³H]-Spiperone 21-24 Ci/mmol for D₂ receptors, [³H]-SCH23390 75-85 Ci/mmol for D₁ receptors, and [³H]-Para aminoclonidine 48-52 Ci/mmol for α₂-adrenergic receptors. The radioligands were incubated with various concentrations of competing drug and the appropriate membrane source for periods of ' time as follows: 75 minutes at room temperature for D₂ receptors, 15 minutes at 37°C for D₁ receptors, or 30 minutes at room temperature for α₂ receptors. Specific binding was defined using 1μM butaclamol (D₂), 1 μM SCH23390 (D₁), or 1 μM yohimbine (α₂). In addition the D₂ assays contained 30 nM Kotaserin in order to block the binding of ³H-spiperone to 5HT₂ receptors. The assays were terminated by filtration using a 24-port Brandell cell harvester over filters that had been previously soaked in 0.1% polyethyleneimine, and the filters were washed three times by filtration of cold buffer. The filters were then placed in 5 ml scintillation vials to which 4 ml of Beckman Ready-Protein was then added, and each vial was counted for 2 minutes in a Beckman 3801 scintillation counter calibrated for conversion of cpm to dpm. Binding data were analyzed using the Ligand program of Munson and Rodbard (1980). The results are presented as K_i values if the data were best fitted to a one-site model, or as K_H and K_L values if a two-site model produced the better fit.

Results of the binding tests are summarized in Table 1 below:

Table 1

RECEPTOR AFFINITIES (Ki, nM)

Example D₂ (K_L) D₁(K_L) α₂

Compound

14 340 1,350 2,600

2 125 12,000 500

12 47 8,964 11,000

9 66 2,130 100

N-0437 110 1,000 190

This table shows high dopamine D₂ receptor affinities of compounds chosen from the examples above, with unexpectedly high degrees of selectivity and specificity. The compound N-0437, a potent dopamine D₂ a ganist is included as a reference compound for comparative purposes. While particular embodiments of the invention have been described it will be understood of course that the invention is not limited thereto since many obvious modifications can be made and it is intended to include within this invention any such modifications as will fall within the scope of the appended claims.

Claims

We claim:

1. Optically active or racemic compounds having the formula

where R₂, R₃ and R₄ are each selected from the group consisting of H and OA with the provision that at least one of R₂, R₃ and R₄ is H, that R₂ and R₄ are not both OA; A is

H or is selected from the group consisting of hydrocarbyl radicals said hydrocarbyl radicals being further optionally substituted with radicals selected from the group consisting of aromatic residues and

-

R₅ is selected from the group consisting of alkyl and aromatic residues, having between 1 and 12 carbon atoms; n is an integer between 1 and 4; R_{6 is an alkyl chain} _{comprising between 1 and 4 carbon atoms}, X is selected from the group consisting of -CH₂-, oxygen, sulfur, and nitrogen, with the provision that when X is not -CH₂-, R₁ is selected from the group consisting of

wherein Z is oxygen, nitrogen or sulfur, wherein Y is selected from the group consisting of hydroxy, nitro, cyano, azido, amino, acylamino, carboxyamido, trifluoromethyl, sulfate, sulfonamido, halogen, hydrocarbyl and heteroatom-substituted hydrocarbyl radicals, wherein said heteroatoms are selected from the group consisting of halogen, nitrogen, oxygen, sulfur and phosphorus and said hydrocarbyl radicals comprise from 1 to 12 carbon atoms, and a is an integer of from zero to 3; and with the further provision that when X is -CH₂-, R₁ is selected from a group consisting of -C-Aryl and -C-Z-Aryl wherein R₈ is hydrogen,

aryl, or R₆; and further wherein R₉ is aryl, R₆, -OH, NH , or -N(R

6..) 2„; or R1. is

wherein B is oxygen, sulfur or two hydrogen atoms, and a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 wherein A is hydrogen or a hydrocarbyl radical having between 1 and 12 carbon atoms selected from a group consisting of phenyl, alkyl and alkyl substituted with aromatic residues.

3. The compound of claim 2 wherein A is selected from the group consisting of and R₅ is

selected from the group of alkyl, alkyl substituted with aryl radicals, and aryl radicals having between 1 and 12 carbon atoms.

4. The compound of claim 1 wherein R₅ is selected from the group consisting of phenyl, methyl, t-butyl, o-methylphenyl, o-, m- and p-methoxyphenyl, p-isopropylphenyl, and nonyl.

5. The compound of claim 1 wherein X is selected from the group consisting of nitrogen, oxygen and sulfur, and R₂ is OA and A is H.

6. The compound of claim 5 wherein R₁ is selected from the group consisting of thienyl, phenyl, hydroxyphenyl, dimethylphenyl , furanyl and napthalenyl .

7. The compound of claim 6 wherein the R₁ is selected from the group consisting of 2-thienyl, 3-thienyl, 3-hydroxyphenyl, 2,6-dimethylphenyl, and 4-hydroxyphenyl.

8. The compound of claim 1 where n is 2, X is selected from oxygen or -CH₂-, and R₂ is OA.

9. The compound of claim 5 wherein Y is selected from the group consisting of hydroxy, nitro, cyano, azido, ammo, acylamino , and cαrboxyamido.

10. The compound of claim 5 wherein Y is selected from the group consisting of trifluoromethyl, sulfate, halogen, hydrocarbyl and heteroatom-substituted hydrocarbyl radicals having between 1 and 12 carbon atoms.

11. The compound of claim 10 wherein the heteroatoms are oxygen, nitrogen or sulfur.

12. The compound of claim 1 wherein R₁ is selected from the group consisting of

13. The compound of claim 12 wherein R₉ is selected from the group consisting of or -N(R₆)₂.

14. The compound of claim 12 wherein Rg is selected from the group consisting of aryl, -R₆, -NH₂, -OH and -OR₆.

15. The compound of claim 1 wherein R₁ is

and B is selected from the group consisting of oxygen and two hydrogen atoms.

16. The compound of claim 15 wherein B is two hydrogen atoms.

17. The compound of claim 1 wherein R₁ is

X is oxygen, and Z is oxygen, nitrogen or sulfur.

18. The compound of claim 1 wherein R₁ is selected from the group consising of

wherein X is oxygen, Y comprises 1 to 5 carbon atoms, and a is an integer from 0 to 2.

19. The compound of claim 1 wherein R₁ is

X is oxygen and Y is a hydrocarbyl radical comprising 1 to 12 carbon atoms.

20. The compounds of claim 17, 18, or 19 wherein Y comprises no more than 6 carbon atoms, and a is 0 to 2.

21. The compound of claim 19 where Y is methyl and a is

2.

22. The compound of claim 19 wherein a is zero.

23. The compound of claim 20 wherein A is H and R₆ is propyl.

24- The compound of claim 1 selected from the group consisting of 2-[N-n-propyl,N-3,3-diphenylpropylamino]-5-hydroxytetralin; 2-[N-n-propyl,N-(2-phenoxy) ethylamino]-5-hydroxytetralin; 2-[N-n-propyl,N-2,2-diphenylethylamino]-5-hydroxytetralin; and 3-[2-[propyl(l,2,3,4-tetrahydro-5-hydroxy-2-naphthalenyl)amino] ethyl]-1(3H)-isobenzofuranone.

25. A method comprising inducing a dopaminergic response in a patient by administering a pharmacologically-effective amount of a compound represented by the formula

H or is selected from the group consisting of hydrocarbyl radicals, said radicals being further optionally substituted with radicals selected from the group consisting of aromatic residues and

R₅ is selected from the group consisting of alkyl and aromatic residues having between 1 and 12 carbon atoms; n is an integer between 1 and 4; R₆ is an alkyl chain comprising between 1 and 4 carbon atoms, X is selected from the group consisting of -CH₂-, oxygen, sulfur, and nitrogen, with the provision that when X is not -CH₂-, R₁ is selected from the group consisting of

wherein Z is oxygen, nitrogen or sulfur, wherein Y is selected from the group consisting of hydroxy, nitro, cyano, azido, amino, acylamino, carboxyamido, trifluoromethyl, sulfate, sulfonamido, halogen, hydrocarbyl and heteroatom-substituted hydrocarbyl radicals, wherein said heteroatoms are selected from the group consisting of halogen, nitrogen, oxygen, sulfur and phosphorus and said hydrocarbyl radicals comprise from 1 to 12 carbon atoms, and a is an integer of from zero to 3; and with the further provision that when X is -CH₂-, R₁ is selected from a group consisting of

wherein R₈ is hydrogen, aryl, or R₆; and further wherein R₉ is aryl, R_6' -OH, -NH₂, -OR₆, or -N(R₆)₂; or R₁ is

26. The method of claim 23 wherein A is hydrogen, or a hydrocarbyl radical having between 1 and 12 carbon atoms selected from a group consisting of phenyl, alkyl and alkyl substituted with aryl radicals.

27. The method claim 24 wherein A is selected from the group consisting of

and R5 is selected from the group of alkyl and aryl radicals having between 1 and 12 carbon atoms.

28. The method of claim 23 wherein R5 is selected from the group consisting of phenyl, methyl, t-butyl, o-methylphenyl, o-, m- and p-methoxyphenyl, p-isopropylphenyl and nonyl.

29. The method of claim 23 wherein X is selected from the group consisting of oxygen, nitrogen and sulfur, and R₂ is OA and A is hydrogen.

30. The method of claim 29 wherein Y is selected from the group consisting of hydroxy, nitro, cyano, azido, amino, acylamino, and carboxyamido.

31. The method of claim 29 wherein Y is selected from the group consisting of trifluoromethyl, sulfate, halogen, and hydrocarbyl and heteroatom-subs tituted hydrocarbyl radicals having between 1 and 12 carbon atoms.

32. The method of claim 31 wherein the heteroatoms are oxygen or sulfur.

33. The method of claim 28 wherein R₁ is selected from wherein X is -CH₂-.

.

34. The method of claim 33 wnerein R9 is selected from the group consisting of and -N(R₆)₂.

35. The method of claim 34 wherein R₉ is selected from the group consisting of aryl, R₆, -NH , -OH, and -OR₆.

36. The method of claim 23 wherein R₁ is

and X is oxygen, and B is selected from the group consisting of oxygen and two hydrogen atoms.

37. The method of claim 36 wherein B is two hydrogen atoms.

38. The method of claim 36 wherein B is oxygen.

39. The method of claim 23 wherein R₁ is

X is oxygen , and Z is oxygen or sulfur .

40. The method of claim 23 wherein R₁ is selected from the group consisting of

and X is oxygen, Y comprises 1 to 5 carbon atoms, and a is 0 or .1.

41. The method of claim 23 wherein R₁ is

X is oxygen, and Y is a hydrocarbyl radical comprising 1 to 12 carbon atoms.

42. The method of claim 23 wherein R₁ is

Y is methyl and a is 2,

43. The method of claim 23 wherein R₁ is and a is zero.

44. The method of claim 39, 40 or 41 wherein X is oxygen, Y comprises no more than 5 carbon atoms, and a is 0 to 2.

45. The method of claim 29 wherein R₁ is selected from the group consisting of thienyl, phenyl, hydroxyphenyl, furanyl and napthalenyl.

46. The method of claim 45 wherein the napthalenyl is selected from the group consisting of 2-thienyl, 3-thienyl, 3-hydroxyphenyl, and 4-hydroxyphenyl.

47. The method of claim 23 wherein n is 2, X is selected from oxygen or -CH₂-, and R₂ is OA.

48. The method of claim 47 wherein A is H and R₆ is propyl.

49. The method of claim 23 selected from the group consisting of 2-[N-n-propyl,N-3,3-diphenylpropylamino]-5-hydroxytetralin; 2-[N-n-propyl, N-2-(2-phenoxy) ethylamino]-5-hydroxytetralin; 2-[N-n-propyl,N-2,2-diphenylethylamino]-5-hydroxytetralin; and 3-[2 -[propyl (1,2,3,4-tetrahydro-5-hydroxy-2-naphthalenyl) amino]ethyl]-1(3H)-isobenzofuranone.