CS235335B2 - Method of tautomer 5-substituted 4,4a,5,6,7,8,8a,9-octahydro-1h(a 2h)-pyrazolo(3,4-g) quinolines production - Google Patents

Abstract

Process for the production of 5-substituted tautomers 4s4a, 5,6,7,8,8a, 9-octahydro- -1H (and 2H) pyrazolo (3,4-g of ehinalines of formulas IIIa and IIIb in which R "represents an alkyl group having 1 to 2 carbon atoms 3 carbon atoms, characterized in that the forq derivative is of the formula IVb in which 3 "is as defined above. or a tautomer thereof, is left in an aqueous medium react with hydrazine.

Description

The present invention provides an improved process for the preparation of tautomeric 5-substituted 4,48,5,6,7,8,8a, 9-octahydro-1H (and 2H) -pyrazolo [3,4-g] quinolines using novel intermediate ketoderivatives.

U.S. Pat. No. 4,198,415, issued April 15, 1980, and U.S. Pat. No. 4,230,861, issued October 28, 1980, disclose a group of octahydropyrazolo [3,4-g] quinolines. These publications describe both the intermediate fat end products and one of the processes described above in the above publications can be illustrated by the following reaction scheme:

- -_ * ^o - ^R1 is H, ^{CN, and} -n-Chx ^{'! J} I

R ^C H ₃ I

l L (lil) (Illb)

In all of the diagrams

R is hydrogen, C1-C3 alkyl, allyl or benay, and

R ¹ represents a hydrogen atom or a radical of COOZ ', wherein z' denotes an alkyl group having 1 or 2 carbon atoms, a henzyl group, an alpha-methylbenzyl group or a phenylethyl group.

Those compounds of formula (IIIa) or (IIIb) wherein R ¹ is hydrogen and R is C 1 -C 3 alkyl or allyl are useful as inhibitors of prolactin secretion and for the treatment of Perkinson syndrome. Those compounds of formula IIlaune IIIb wherein R is hydrogen as well as f ', where R is benzyl or where R ¹ is COOZ' are useful as intermediates. These products are converted to the corresponding drugs by the procedures described in the aforementioned patents, the agent used to convert the 1-substituted 6-oxodecahydro-hydroquinoline optionally substituted at the 6-position of Formula 1 to an intermediate of Formula II is dimethylformamide acetal, such as dimethylformamide. dimethylacetal.

In accordance with the present invention, it has now surprisingly been found that the novel intermediate ketoderivatives provide a better route for the preparation of a certain group of compounds falling within the abovementioned general formulas IIIa and IIIb. The advantages associated with the use of these novel mesiproducts are the possibility of using cheaper reagents, higher yields of the final products, and that the intermediate ketoderivative need not be isolated (although it can be isolated if desired).

Accordingly, the present invention provides a process for the preparation of tautomeric 5-substituted 4,4a, 5,6,7,8,8a, 9-octahydro-1H (and 2H) pyrazolo [3,4-g] quinolines of formulas IIIa and IIIb.

R '(IIIa) (IIIb) in which

R * represents an alkyl group having from 1 to 3 carbon atoms, characterized in that the formyl derivative of the general formula IVb

(IVb) wherein

R *, as defined above, or a tautomer thereof, is reacted with hydrazine in an aqueous medium.

Starting formyl derivatives, which may exist in a number of tautomeric forms, may be prepared by the following reaction scheme I:

Reaction Scheme I (I) a C1 -C6 alkyl formate ester in the alkyl moiety.

R (IVa) (IVb) dvc) two)

In accordance with Reaction Scheme I, the trans-dl-1-substituted 6-oxo-decahydroquinoline of formula I is formulated by reaction with an alkyl formate containing 1 to 6 carbon atoms in the alkyl moiety in the presence of a base to form trans-dl-1-aubst.6. -oxo-7-formyldecahydroquinoline represented by a series of tautomeric structures (see formulas IVa-IVd). This intermediate is expediently not isolated (although understandable) and is not characterized, but is immediately reacted in situ within the meaning of the invention with hydrazine to give a mixture of tautomers, i.e. trans-dl-5-substituted 4,4e, 5e, 5e, 5e, 5e, 5e. , 6,7,8,8a, 9-octa235335 hydro-1H-pyrazolo [3,4-g] quinoline (IIIa ¹¹ ) and trans-dl-5-substituted 4,4a, 5,6,7,8,8 α, 9-octahydro-2H-pyrazolo [3,4-g] quinoline (IIIb).

The formulated product described above by the four tautomeric structures (Formulas IVa-IVd) in aqueous solution is likely to exist predominantly as the zwitterion shown in Formula IVb. However, all the above-mentioned teutomeric forms are in dynamic equilibrium, and when one of these structures is plotted or described herein, it also includes all other structures. The invention also encompasses resonant structures of the various formulas mentioned above, such as

(IVb)

The process of Reaction Scheme I is a modification of the Claisaen condensation in which a methylene group activated by the presence of a adjacent carbonyl group can be acylated in the presence of a base. As the base is usually sodium ethoxide, it will be understood that other bases, such as alkali metal tert-alkoxides and alkali metal hydrides, in particular potassium tert-butoxide, potassium tert-amyl oxide or sodium hydride, may be used for this purpose.

The Claissen condensation reaction (I → IV) is usually carried out in an ethanolic solution, although other lower alkanols and similar polar anhydrous solvents can of course be used as the reaction medium. Examples of suitable solvents include tetrahydrofuran, diethyl ether, dimethoxyethane, dioxane, dimethylsulfoxide, dimethylformamide and tert-butanol, preferably tetrahydrofuran, which may also serve as a solvent for the next cyclization step. Although the reaction temperature is not critical, the reaction is preferably carried out at a temperature of about -20 ° C to reflux, in particular in the range of 0 ° C to room temperature.

In the cyclization step (IV → IIIa * + IIIb) according to the invention, hydrazine is mentioned as a particular drug, but hydrazine hydrate or hydrazine salts can be used to the same effect. Suitable solvents for this cyclization step are water, C 1 -C 4 alkanols, in particular tert-butanol, tetrahydrofuran, dimethylsulfoxide, methylene chloride, dioxane and diethyl ether. The reaction may be carried out at a temperature of about 0 ° C to reflux, with room temperature being preferred.

An advantage of the synthetic process described above is that both formylation and cyclization can be carried out in the same reaction vessel. Thus, solvents suitable for both of these reactions are preferably used, such as tetrahydrofuran, dimethylsulfoxide, tert-butanol, dimethoxyethane, diethyl ether and dioxane, in particular tetrahydrofuran. If desired, water or a C 1 -C 4 alkanol can be added to the reaction system. The reaction can be carried out at a pH in the range of about 13 to 0, and preferably at about pH 9. A preferred pH of about 9 is achieved by adding a 10X hydrochloric acid solution (1 mol) to the reaction mixture. Although a temperature range of about 0 ° C to reflux can be used, room temperature is nevertheless preferred.

A second advantage of the process according to the invention is that the yields of tautomeric pyrazoles (IIIa + IIIb ') are higher than those obtained in the prior art process using dimethylformamide dimethyl acetal as the reagent. Another advantage is that the preferred formulating agent - ethyl formate - is relatively inexpensive compared to dimethylformamide dimethylacetal.

It should be noted that the numbering of the starting ketone of formula I differs from that of the final pyrazole product of formula III. Thus, the asymmetric ring-linking carbon adjacent to the quinoline nitrogen is numbered 8a in the starting ketone, while in the pyrazole derivative 4a. The second asymmetric carbon joining the rings is then numbered 4a in the ketoderivative, while in the final product 8a. Racemic pairs of formulas IIIa and IIIb are commonly referred to as cis-dl-pair and trens-dl-pair. The configuration of the molecule to ^ ^ 4a ^and 8a ^VC j ^{s of} 61-pair will therefore 4aR, 4aS, and 4aS, 8aR, and a trans-dl pair 4aR, 8aR and 4aS, 8aS. Of course, the configurations in the starting materials are retained during the synthesis of pyrazoloquinoline because the Claisen condensation and subsequent cyclization using hydrazine do not affect the configuration at these optical centers.

Our related Czechoslovak patent specification 234 050 describes a process for separating trans-dl-1-n-propyl-6-oxodecahydroquinoline corresponding to the general formula I in which R is n-propyl to the individual stereoisomers of formula Ia (4aR, 8aR) ) and Ib (4aS, 8aS).

? C ₃ ^H 7 (Ib). The above process can be used for both the separated isoaers (Ia and Ib) and the trans-dl-racemate as shown in Reaction Scheme 1.

The process of Scheme I with the subsequent cyclization of the invention is shown in Scheme II below, wherein the isomer, i.e., 4aR, 8aR-1-n-propyl-6-oxodecahydroquinoline, is used to prepare the desired 4aR, 8aR-4 > 5,6,7,8,8a, 9-octahydro-1H (and 2H) pyrazolo [3,4-g] quinoline.

Reaction Scheme II

H

O

H hcooc ₂ h ₅ nC ₃ H ₇ base

H

OH

(IVa (Ia)

N

(lile ') <IIIb')

The advantage of the process described in Reaction Scheme II is that instead of cyclizing the corresponding trans-dl-racemate and cleaving the resulting trans-dl-pyrazoloquinoline, the trans-dl-ketone in X is cleaved and the pure 4aR, 8aR-stereoisomer (Ia) is cyclized to optically active trans-4hR, 8aR-octahydropyrazolo [3,4-g] quinoline. Since at least half of the racemic mixture falls off during cleavage, it is of course much more economical to remove half of the starting material than half of the resulting product, especially considering that organic reactions such as cyclization of ketoquinoline to pyrazoloquinoline never take place quantitatively.

The invention is illustrated by the following non-limiting examples.

Example 1

Weigh 1.5 g of potassium tert-butoxide into a 250-ml round-bottom flask and dissolve by adding 25 ml of tetrahydrofuran. To this t-butoxide solution is added a solution of 0.8 µl of ethyl formate and 0.97 g of trans-dl-1-propyl-6-oxodecahydroquinoline in 10 µl of tetrahydrofuran, the reaction mixture is allowed to react at room temperature for about 45 minutes, 2 L of hydrazine and appropriate amounts of 15% aqueous hydrochloric acid are added thereto to reduce the pH to about 9. The resulting mixture is stirred at room temperature for 30 minutes, after which time thin layer chromatography indicates that there is no more default ketoderive. The reaction mixture was poured into 10% aqueous sodium hydroxide and the basic mixture was extracted with an equal volume of methylene dichloride. The extract was dried and the solvent was evaporated in vacuo. 1.31 g of a crude oil consisting of crude trans-dl-5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (and 2H) pyrazolo- [3,4- g] quinoline.

Example 2

An appropriate amount of a 55% sodium hydride suspension in mineral oil containing 360 mg (15 mmol) of sodium hydride was added to a 25 mL round bottom flask and the mineral oil was removed by washing three times with hexane. The residual sodium hydride is suspended in 6 ml of tetrahydrofuran, 740 ml of ethyl formate and 1 drop of anhydrous ethanol are added first, followed by 975 mg of trans-dl-1-n-propyl-6-oxo-decahydroquinoline in 4 ml of tetrahydrofuran.

The reaction mixture, which began to boil almost immediately, was refluxed for about 45 minutes. After this time, the reaction mixture contains no starting material according to thin layer chromatography. After addition of 50 ml of water and 4 ml of hydrazine, the pH is adjusted to about 9 with dilute aqueous hydrochloric acid and the mixture is stirred at room temperature overnight, whereupon a precipitate is formed. Isolation of this precipitate afforded 373 mg of trans-dl-5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (u 2H) pyrazolo [3,4-g] quinolines m.p. 78-84 ° C.

For ^{C 13 H} 21 ^N 3 calculated C 71.19%, H 9.65%, N 19.16%;

Found: C, 70.89; H, 9.15; N, 19.34.

Further material is obtained by pouring the filtrate into dilute aqueous sodium hydroxide solution and extracting the alkaline solution several times with methylene dichloride. The methylene dichloride extracts were dried and concentrated to give 623 mg of a white foam which was purified by chromatography on silica gel using tetrahydrofuran with a trace amount of ammonium hydroxide as eluent. The initially eluted fractions containing the desired pyrazolo [3,4-g] quinoline were combined and evaporated to give 437 mg of a colorless oil.

The oily material was converted to the dihydrochloride which melts at 252-263 ° C after recrystallization from methanol-acetone.

The above experiment was repeated using 125 mg of trans-4aR, 8aR-n-propyl-6-oxo-decahydroquinoline and accordingly reducing the amount of ethyl formate and base (sodium hydride instead of potassium tert-butoxide). After virtually complete completion of the reaction (due to the disappearance of the starting material from the thin layer chromatographic sample of the reaction mixture), the reaction mixture was poured into dilute aqueous sodium hydroxide solution and the basic mixture was extracted with methylene dichloride. Drying of the methylene dichloride extract and subsequent evaporation of the solvent in vacuo gave about 144 mg of a colorless viscous oil, which gave only one spot on thin layer chromatography. The oily material was dissolved in methanol, and 3.2 mL of 0.20 N aqueous hydrochloric acid was added. Concentration of the resulting yellow solution gave a semi-solid yellow color which was dissolved in methanol. The methanolic solution was decolorized with activated carbon and this was removed by filtration through diatomaceous earth. Evaporation of the solvent and recrystallization of the residue from a mixture of methanol and ethyl acetate gave 80 mg of buttery-yellow powder of 4aR, 8aR-5-n-propyl-4,4a, 5,6,7, 8,8a, 9-octahydro-1H (e 2H). ) pyrazolo [3,4-g] quinoline with an optical rotation of alpha ^ ^x -121.76 ° (water, c = 1).

Example 3

To a solution of 59.8 g of potassium tert-butoxide in 600 ml of tetrahydrofuran, previously cooled to about 0 ° C, is added a solution of 52 g of optically pure 4aR, 8aR-1-n-propyl-6-oxodecahydroquinoline and 79 g of ethyl formate in 250 ml of tetrahydrofuran. Gas is released during the addition. The reaction mixture is stirred for 0.5 hour at ca. 0 ° C and then at room temperature for an additional hour, 25.6 g of hydrazine are added and the pH of the solution is adjusted to pH ca. 9. The resulting mixture was stirred vigorously at room temperature for 2 hours, then poured into water and the aqueous mixture was made strongly alkaline (pH ca. 13) with dilute aqueous sodium hydroxide. The basic mixture was extracted with methylene dichloride, the methylene dichloride extract was dried and the solvent was evaporated. According to thin layer chromatography, the yellow foam residue contains the desired pyrazoloquinoline together with a small amount of a single impurity.

235336

This residue is dissolved in 1 liter of hot methanol, to which 250 ml of 1 H aqueous hydrochloric acid are added. After concentrating the solution, 65.4 g of 4aH, 8aR-5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (and 2H) pyrazolo [3,4-g] are obtained. quinoline hydrochloride vs fornt of a yellowish solid which, after recrystallization from a mixture of methanol and ethyl acetate, gave 51.7 g (76% yield) of a yellowish solid with an optical rotation (alpha = -112.0 ⁰ water, c 1) j [alpha] 1 H -377.40 (water, C 1).

Analysis:

C, 61.04; H, 8.67; H, 16.43; Cl, 13.68;

Found: C, 61.32; H, 8.53; N, 16.22; Cl, 14.08.

Example 4

To a solution of 3.6 g of potassium tert-butoxide in 50 ml of tetrahydrofuran at 0 ° C is added a solution of 5.0 g of trans-dl-1-n-propyl-6-oxodecahydroquinoline and 2.36 g of ethyl formate in 25 ml. tetrahydrofuran. The resulting solution was stirred at 0 ° C for 15 min and then at room temperature for 17 h. The yellow precipitate formed was filtered off in vacuo and washed with tetrahydrofuran and dried in vacuo. The potassium salt of trans-dl-1-n-propyl-6-oxo-7-forisyldecahydroquinoline is obtained.

NMR (deuterium oxide, δ): 9.00 (ainglet, IH, CHO), 3.02-0.99 (multiplet, 16H),

0.84 (triplet, J = 7, 3H, -CH2 of n-C1H3).

The above 7-formyl derivative can be converted into the corresponding process according to the invention as described above. the product of general formula IIIa 'and Illb ”.

The following are examples of the resolution of the starting materials and products into the individual optically active omers, preparation of the optically active products from the corresponding optically active starting materials, and the results of the pharmacological activity tests of the final compounds.

Example 5 g of trans - (+) - 5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (and 2H) pyrazolo [3,4-g] quinoline dihydrochloride Dissolve in water and basify the aqueous solution by adding solid potassium carbonate. The aqueous phase is extracted several times with chloroform to remove the free base which is insoluble in the alkaline layer and is separated from it. The extracts were combined, dried and the solvent was evaporated in vacuo. 4.7 g of a clear orange oil consisting of trans - (+) - 5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (e2H) -pyrazolo [3, 4-g-ehinoline in the free base form resulting from the neutralization described above.

1.8 g of this free base are dissolved in methanol and a hot methanol solution of 1.5 g of (+) - tartaric acid is added to this solution. The reaction solution is heated to boiling for 5 minutes and then allowed to cool to room temperature. A colorless crystalline solid enriched in 4aS, 8aS-5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (and 2H) -pyrazolo [3,4-g] quinoline is precipitated with (+) - tartaric acid. The precipitate was filtered off and the filter cake was washed with ether to give 1.46 g of solid product. This fraction has an optical rotation of [alpha] (water) +32.76?

and melts at 173-177 ° C. This solid material, recrystallized from hot methanol, gave 0.70 g of a colorless crystalline solid having an optical rotation of .alpha. (Water) &gt; + 58.44 ° and melting at 185-186 ° C. This solid was recrystallized from hot methanol to give 0.15 g of pure salt and 4aSpeaS-5-n-propyl-4,4a, 5,6,7,8,8e, 9-octehydro-1H (and 2H). -pyrasolo [3,4-g] quinoline 8 (+) - tartaric acid in the form of a colorless crystalline product with an optical rotation of [alpha] 3? (water) + 93.88 ° and m.p. 201-202 ° C. Further recrystallization will neither improve the melting point nor the optical rotation.

For C ^ HHgyNN ^O »requires C, 55.27; H, 7.37; N, 11.37;

found: C 55.00, 7.13 9, 11.19 µM,

Example 6

The trans - (+) - 1-n-propyl-6-oxadecahydroquinoline is cleaved as described below.

g of (-) - di-p-toluoyltartaric acid is dissolved in 75 ml of warm methanol and this solution is added to a solution of 5.05 g of trans - (+) - 1-n-propyl-6-oxodecahydroquinoline in 15 ml of methanol. The reaction mixture was heated to boiling and then allowed to cool to room temperature at which it was allowed to stand overnight. Seeding the crystals of the authentic compound induces crystallization, the crystalline tartrate is isolated by filtration, and the filter cake is washed with methanol. There were obtained 2.813 g (18.7 g) of a white crystalline solid consisting of (-) - di-p-toluoyltartrate 4aR, 8aR-ln-propyl-6-oxodecahydroquinoline having an optical rotation of [.alpha.] D = -107.49 DEG (methanol, c = 1).

The filtrates and mother liquors from the previous process or from larger scale analogous procedures were combined to give a solution of 1-n-propyl-6-oxo-decahydroquinoline enriched in the 4aS, 8aS-isomer, with reduced content of 4aR, 8aR-isomer. This solution was treated with (+) - ditoluoyltartaric acid monohydrate as described above to give 4aS, 8aS-1'-propyl-6-oxodecahydroquinoline - (+) - ditoluoyltartrate having an optical purity of about 80 9. 250 ml of methanol, 12 g of a white crystalline powder which melts with decomposition at 167.5 to 169.5 DEG C., [.alpha alfaj ^ _s + 106.3 ° (methanol, c = 1.0); [.alpha.] D @ 20 = + 506.7 DEG (methanol, c = 1.0). These data indicate an optical purity of about 90. A second crop, obtained from the mother liquors of the above crystallization, yields 2.3 g of a white solid melting at 166.0-166.5 ° C with an optical rotation of [alpha] = 106.6 °; [.alpha.] D @ 20 = + 510.8 DEG (in both cases methanol, c = 1.0), which indicates an optical purity of about 94. After recrystallization of the first and second crop of crystals from methanol, a white solid is obtained. the free base was prepared by standard procedures. This free base affords 4.14 g of a colorless oil, boiling at 82-86 ° C / 1 mm Hg, consisting of 4aS, 8aS-1-n-propyl-6-oxodecahydroquinoline, with an optical rotation of [.alpha.] @ + ⁵ +86, 2 °; [alpha] ^ 55 '+ 376.6® (both methanol, c = 1.0) with an optical purity of about 98 9.

4.04 g of the free base prepared above are dissolved in 1.0 ml of methanol, to which is added a solution of 8.35 g of (+) - ditoluoyltartaric acid monohydrate in 65 ml of methanol. The resulting solution was concentrated to a volume of 50 ml at which point a precipitate began to precipitate. The reaction mixture was allowed to stand overnight at room temperature during which time further crystallization occurred.

After filtering off the crystals, 10.87 g of a white powder is obtained, melting at 167.0-167.5 ° C. This salt is converted into the free base, which distills at 83 to 86 ° C / 17,3 Pa and has an optical rotation [alpha] | ⁵ = 86.9 °; [.alpha.] D = 378.8 DEG (in both cases methanol, c * 1.0), which indicates an optical purity of about 98%.

Alternatively, trans - (+) - 1-n-propyl-6-oxodecahydroquinoline can be directly treated with (+) - di-p-toluoyltartarine to give 4aS, 8aS-1-n-propyl-6-oxodecahydroquinoline - (+) - di p-toluoyltartrate, which is purified as above for the 4aR, 8aR-isomer salt.

Example 7

The 4eS, 8aS-ln-propyl-6-oxodecahydroquinoline prepared as described above is converted to 4aS, 8aS-5-n-propyl-3,4,4e, 5,6,7,8,8a, 9- octahydro-1H (E 2H) -pyresolo [4,3-g] quinoline.

7.7 g of potassium tert-butoxide are dissolved in 85 ml of tetrahydrofuran, the resulting solution is cooled to about 0 ° C, and a mixture of 6.7 g of 4aS, 8aS-1-n-propyl-6-oxo-decahydroquinoline and 10 ml is added. 2 g of ethyl formate in 40 ml of tetrahydrofuran. Gas evolution occurs during the addition. The reaction mixture was allowed to warm to room temperature and a sample was subjected to thin layer chromatography, indicating no starting material was present. 6 ml of hydrazine hydrate are added and then the pH is adjusted to about 9 with 10% hydrochloric acid. The mixture is stirred vigorously at room temperature until no intermediate formyl ketone is present according to thin layer chromatography. The reaction mixture was poured into dilute aqueous sodium hydroxide solution and the basic mixture was extracted with methylene dichloride. The methylene dichloride extract was dried and the solvent was evaporated in vacuo to give 9 g of a colorless panic product. This bovine material was dissolved in 100 ml of methanol to which was added an equivalent amount of M aqueous hydrochloric acid. The resulting solution was concentrated to give a white solid which, after recrystallization from methanol / ethyl acetate, gave 5.69 g of 4aS, 8aS-5-n-propyl-4,4a, 5,6,7,8,8a, 9 -octahydro-1 H (and 2H) -pyrazolo (3,4-g) quinoline hydrochloride.

The compounds described in the above examples exhibit their activity as D-1 dopamine agonates in various ways. For example, 4aS, 8aS-5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (a2H) -pyrazolo (4,3-g) quinoline stimulates the formation of cyclic adenosine monophosphoric acid in the rat striatal membrane.

This potency is determined by the procedure described by Wong and Reid in Communications in Psyehopharmacology, i, 269 (1980). 4aS, 8aS-5- * n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (and 2H) -pyrasolo (4,3-g) quinoline, corresponding to 4aR, 8aB The enantiomer and the corresponding racemate are tested for the ability to activate adenylate cyclase in the rat striatal membrane, which activation is measured as the increase in cyclic adenosine monophosphoric acid concentration. The results of this assay are shown in the table. • How positive control is dopaain used. The first column of Table 1 shows the test substance, the second column the concentration of the test substance and the third column the cyclic adenosine monophosphoric acid production as a percentage of the control.

T a b u 1 k a 1

Test substance Concentration (juaol) Cyclic production % adenosine monophosphoric acid compared to control Dopamine . 10 50 100 ALIGN! 149.7 + 7.2 215.5 + 28.8 183.8 + 12.5 ^κ) Racemate 50 116.5 + 13.3 4aB, 8aR-enantiomer 50 114.2 + 10.4 4aS, SaS-enantiomer 50 141.8 + 9.3 »

In the presence of 10 yumol guanosine triphosphate, the baseline adenylate cyclase activity in the rat striatal membranes (+ standard deviation) was 134.9 ± 6.1 pmol / min / mg protein. Compounds are tested in three or more separate experiments. Significant (p <C 0.025) cyclic adenosine monophosphoric acid production is indicated by an asterisk (x).

According to the data presented in Table 1, only the 4aS, 8aS-enantiomer significantly increased cyclic adenosine monophosphoric acid production, suggesting the efficacy of the D-1 dopamine agonist.

A second, particularly sensitive indicator of D-1 agonist activity is the release of cyclic adenosine monophosphoric acid from tissue sections using the procedure described by Stoof and Kebabian (ibid.). In this procedure, the striatal tissue is separated from the rat brain and cut into fragments of 0.3 mm x 0.03 mm. Tissue fragments are suspended in a suitable buffer system (for example, Earl Balanced Salt Solution) and a gas stream consisting of 95 parts oxygen and 5 parts carbon dioxide is continuously introduced into the suspension while maintaining the temperature at 37 ° C. Immediately before use, the tissue fragments are transferred to fresh medium, to which bovine serum albumin (2.5 mg / ml) and 3-isobutyl-1-methylxanthine (1 mmol) are added to prevent the decomposition of cyclic adenosine monophosphoric acid. Tissue fragments are incubated in buffer without addition of test substances and then transferred to the same medium to which test compound has been added. Incubation samples (without addition of test compound) were assayed for cyclic adenosine monophosphoric acid concentration using a specific radioimmunoassay procedure. The effect of the test substance (s) on cyclic adenosine monophosphoric acid release is expressed as a percentage of the control status.

The test is performed using the following environment:

Component Concentration (mg / liter) sodium chloride 4 800 Potassium chloride 402.6 sodium bicarbonate 2 201.1 sodium dihydrogen phosphate 137.99 magnesium sulfate heptahydrate 147.88 d-glucose 1 009 calcium chloride dihydrate 191.1 phenol red ¹⁰

In the above-described experiments, Stoof and Kebabian sulpiride used to suppress the negative (anti D-1) effect of all drugs acting as D-2 dopamine agonists.

The authors have shown that the D-2 agonist suppresses the production of cyclic adenosine monophosphoric acid (an effect contrary to that produced by the D-1 agonist). Sulpiride is known to be an antagonist of the D-2 pituitary receptors. The addition of sulpiride to the test system, such as the syrup in the assay described above, blocks all D-2 effects of the test substance in terms of reducing cyclic adenosine monophosphoric acid production. Stoof and Kebabian demonstrated a loss of the effect of sulpiride on the production of cyclic adenosine monophosphoric acid in rat striatal tissue using SKF 38393 as a pure D-1 agonist, suggesting that D-2 receptors are not used and that the compound is not effective as a D-2 agonist .

Results of one such assay using 4aS, 8aS-5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (and 2H) -pyrazolo [3,4-g] quinoline- of dihydrochloride (Compound A) are listed in Table 2. Column 1 of this table lists the compound added (if any), Column 2 of the compound concentration, Column 3 of the cyclic adenosine monophosphoric acid concentration and Column 4 of cyclic adenosine monophosphoric concentration of acid expressed as a percentage.

Table 2

Test substance Concentration Concentration cyclic adenosine monophosphorus acid Increase XX) cyclic adenosine monophosphoric acid concentration 71.6 + 8.2 0 AND 5 x 10 ⁷ ll 131.0 + 9.2 83 AND 5 x 10 ⁶ ll 160.1 + 23.8 124 A + sulpiride (10 ⁶ li) 5 x 10 &lt; ⁷ & gt ^; 143.7 + 6.2 100 ALIGN!

The table above shows that sulpiride has no effect on increasing the excretion of cyclic adenosine monophosphoric acid.

In the above work, Stoof and Kebabian found that the racemate, i.e. trans - (+) - 5-n-propyl-4,4a, 5,6,7,8,8a, 9-octehydro-1H (and 2H) - pyrazolo- [4,3-g] quinoline (LY141865) reduces the concentration of cyclic adenosine monophosphoric acid (see page 367, graph G of the above authors). The addition of sulpiride has little or no effect and at best returns the cyclic adenosine monophosphoric acid concentration to a control level. The same racemic compound reduces the effect of SKP38393 by increasing the level of cyclic adenosine monophosphoric acid by 57 + 8% (see Figure 3 on page 368 of the authors cited above). The addition of sulpiride suppresses this effect and the levels of cyclic adenosine monophosphoric acid are essentially the same as that of SKF38393 alone.

The data presented by Stoof and Kebabian essentially agree with the conclusion that the 4aR, 8aR-enantiomer, which is a known D-2 agonist, is an effective component of the racemate (LY141865) in reducing the production of cyclic adenosine monophosphoric acid, which effect is again suppressed by sulpiride. The trans - (+) - omer in the D-2 agonist activity assay does not show activity as a D-2 agonist.

In a separate but similar experiment, it was confirmed that SKF38393 increased the production of cyclic adenosine monophosphoric acid (145 X at a concentration of 10 ^-6 L). This effect is reduced by the addition of 4aR, 8aR-5-n-propyl-4,4a, 5,6,7,8,8a, 9-octahydro-1H (and 2H) -pyrazolo [4,3-g] quinoline, trans- of the (-) - enantiomer and D-2 agonist at a dose of 0.5 x 10 -mol (from 145% to 42%). This effect is suppressed by the addition of sulpiride (10 µM) to the system.

Claims (3)

OF THE INVENTION A process for the preparation of the 5-substituted 4,40,5,6,7,8,8a, 9-octahydro-1H (and 2H) pyrazolo [3,4-g] quinolines of the general formulas IIIa and IIIb (IIIa) (IIIb) ) in which R represents a C 1 -C 3 alkyl group, characterized in that the formyl derivative of the general formula IVb R in which R is as defined above, or a tautomer thereof, reacted with hydrazine in an aqueous medium. 2. Method according to claim 1, characterized in that a starting material is used. a ketoderivative of formula (IVb) in the 4aR, 8aR configuration. 3. The method of claim 1, wherein the starting ketoderivative of formula (IVb) is in the 4aS, 8aS configuration.