WO2007122274A1

WO2007122274A1 - Acetylcholinesterase-inhibiting compounds for treating alzheimer's disease

Info

Publication number: WO2007122274A1
Application number: PCT/ES2007/000237
Authority: WO
Inventors: Pelayo Camps García; Diego MUÑOZ-TORRERO LÓPEZ-IBARRA; Xavier FORMOSA MÁRQUEZ; Michele Scarpellini
Original assignee: Universidad De Barcelona
Priority date: 2006-04-20
Filing date: 2007-04-19
Publication date: 2007-11-01
Also published as: ES2288406A1; ES2288406B1

Abstract

Compounds of formula (I) and the pharmaceutically acceptable salts or solvates thereof, including any stereoisomer or mixture of stereoisomers, in which R1, R2, R3 and R4 are radicals selected independently from the group consisting of H, Cl, F, Br, CF3, (C1-C4)alkyl, (C1-C4)alkoxyl and nitro; R5, R6, R7 and R8 are radicals selected independently from the group consisting of H and (C1-C6)alkoxyl; n is an integer from 3 to 5; r is an integer from 2 to 5; s is an integer from 1 to 5 and X is a biradical selected from CO and CH2. They behave as acetylcholinesterase inhibitors with two bonding sites and are useful as active principles against Alzheimer's disease.

Description

Acetylcholinesterase inhibitor compounds for the treatment of Alzheimer's disease

The invention relates to acetylcholinesterase inhibitor compounds and a process for their preparation. It also refers to pharmaceutical compositions comprising said compounds and their use for the treatment of Alzheimer's disease.

STATE OF THE TECHNIQUE

Alzheimer's disease, the most common form of dementia in the elderly, is one of the biggest health problems in developed countries along with cardiovascular disorders and cancer. This slow, progressive and finally fatal neurodegenerative disorder is characterized clinically by a notable cognitive decline defined by a loss of memory and learning capacity, together with a reduced ability to develop basic activities of daily life, and a wide range of neuropsychiatric symptoms such such as apathy, verbal and physical agitation, irritability, anxiety, depression, delusions and hallucinations. Alzheimer's disease currently affects approximately 20 million people worldwide, and this amount will increase substantially in the future as the number of elderly people in the population increases, taking into account that the prevalence of Alzheimer's disease doubles every 5 years from 65, with 47% affected among those over 85 years. As a result of the increasing incidence and the devastating effects of this disease, there is an urgent and growing need for effective pharmacotherapy. The multifaceted nature of Alzheimer's disease has led to the development of a variety of approaches for its pharmacological correction. Although enormous progress has been made in the identification of the molecular origins of Alzheimer's disease, there is currently no cure for this disease.

Alzheimer's disease is characterized by two main pathological aspects: amyloid plaques and neurofibrillar clews, in addition to the loss of neuronal cells in specific regions of the brain. An increase in the production of β-amyloid peptide (Aβ) and its subsequent deposition as insoluble amyloid plaques, forming senile plaques Extraneuronal, seems to constitute the key pathological event that triggers the neurodegenerative process in Alzheimer's disease. Different strategies have been developed aimed at reducing, preventing or even reversing the generation and deposition of Aβ with the idea of reducing the rate of progress of the disease and preventing further losses of neuronal cells.

The development of the most advanced of these approaches, which involved immunization with Aβ, was recently discontinued due to the observation of unwanted side effects, such as inflammation of the central nervous system (CNS), during Phase II clinical trials. Other approaches such as the use of β- and γ-secretase inhibitors or β-leaf cutters are promising for the treatment and prevention of Alzheimer's disease, although they are still in their infancy and there is currently no clinical experience available.

In contrast to these approaches, the symptomatic treatment of Alzheimer's disease, in particular the treatment of cognitive deficits, has been successfully addressed through the replacement of deficient neurotransmitters, especially acetylcholine, in the CNS of patients in Ia Alzheimer disease. Thus, research efforts have been directed, among others, to the therapeutic potential of acetylcholinesterase (AChE) inhibitors to slow the progression of the disorder. The most established therapeutic approach for Alzheimer's disease involves the use of a group of indirect colinomimetic agents with the pharmacological profile of AChE inhibitors (tacrine, donepezil, rivastigmine and galantamine), which increase the central cholinergic neurotransmission inhibiting the degradation of Acetylcholine

AChE inhibitors have been shown to be a class of effective medications to improve cognitive function and activities of daily living, and generally have favorable tolerability and safety profiles. Recent evidence suggests that the AChE enzyme also has non-cholinergic secondary functions. Thus, while AChE has a non-cholinergic neurotrophic activity, it can also play a key role in the development of senile plaques, by accelerating the deposition of Aβ. The design and synthesis of new AChE inhibitors capable of interacting simultaneously with the active site and with the peripheral site of the AChE enzyme (dual-binding AChE inhibitors) as candidates for anti-Alzheimer's drugs with potential to modify the disease currently constitute A very intense research area.

Donepezil, the second anti-Alzheimer drug approved by the FDA, is the only AChE inhibitor of the dual binding site currently marketed, although it was not specifically designed as such. The character of the dual-binding site inhibitor of donepezil may explain its excellent pharmacological profile. On the one hand, donepezil (Cl ₅₀ = 5.7 nM, using rat brain AChE) is the AChE inhibitor, licensed for the treatment of mild to moderate cases of Alzheimer's disease, more widely used. On the other hand, in a recent study on the ability of several AChE inhibitors to prevent aggregation of Aβ induced by human recombinant AChE, a significant anti-aggregating effect for donepezil (22% inhibition) was observed, while specific ligands Peripheral site such as propidium showed a greater antiaggregant effect (82% inhibition of aggregation). The superior pharmacological profile of donepezil has stimulated the development of other Λ / -benzylpiperidine derivatives as potential candidates for drugs for the treatment of Alzheimer's disease.

In recent years, several research groups have described the design, synthesis and pharmacological evaluation of a series of homo- and hetero-dimers containing two identical or different structural units of known AChE inhibitors linked through an oligomethylene chain. The first known AChE inhibitor that was used as a standard compound in this strategy was tacrine, the first drug approved (in 1993) for the treatment of Alzheimer's disease, currently largely displaced from the market due to hepatotoxicity induction. . A large number of tacrine-based dual-binding AChE inhibitors have been developed by different groups, some of which exhibit a very potent Aβ antiaggregant effect. Similarly, tacrine has been used for the design of dual-binding site AChE inhibitors in combination with a donepezil fragment. For example, WO 2004/032929 describes a family of heterodimers, containing the unit of donepezil ndanone and a tacrine residue, which behave as AChE inhibitors of dual binding site and that can be used for the treatment of Alzheimer's disease.

Thus, despite all the research efforts made in the past, the treatment and / or prevention of Alzheimer's disease is far from satisfactory. Therefore, the development of compounds for the treatment of Alzheimer's disease in humans is still of the greatest importance.

EXPLANATION OF THE INVENTION

The inventors have found new compounds that behave as inhibitors of acetylcholinesterase dual binding site showing a high potency of AChE inhibition. Thus, these compounds are very promising agents for the treatment of Alzheimer's disease.

Thus, according to one aspect of the present invention, there is provided a compound of formula (I) ₁ or a pharmaceutically acceptable salt thereof, or a solvate thereof, including any stereoisomer or mixture of stereoisomers, wherein R ₁ , R ₂ , R ₃ and R ₄ are radicals independently selected from the group consisting of H, F, Cl, Br, CF ₃ , (Ci-C ₄ ) -alkyl, (CrC ₄ ) -alkoxy and nitro; R ₅ , Re, R ₇ and Re are radicals independently selected from the group consisting of H and (Ci-C ₆ ) -alkoxy; n is an integer from 3 to 5; r is an integer from 2 to 5; s is an integer from 1 to 5 and X is a birradical selected from CO and CH ₂ .

Preferred compounds of formula (I) are those in which Ri, R ₂ , R ₃ and R ₄ are radicals independently selected from the group consisting of H, F, Cl and Br; R5, R ₆ , R ₇ and Rs are radicals independently selected from the group consisting of H and methoxy, and s is 1.

Most preferred compounds of formula (I) are those in which R ₂ is selected from H and Cl; R ₁ , R ₃ , R ₄ , R ₅ and R ₈ are H; R ₆ and R ₇ are methoxy; n is an integer from 3 to 4; and r is an integer of 2 to 3. Preferred pharmaceutically acceptable salts of the compounds of formula (I) are hydrochloride or dihydrochloride.

The most preferred compounds are the following:

9 - [(2- {4 - [(5,6-dimethoxyindan-2-yl) methyl] pperidin-1-yl} ethanol) amine] -1, 2,3,4- tetrahydroacridine;

6-chloro-9 - [(2- {4 - [(5,6-dimethoxyindan-2-yl) methyl] piperidin-1-yl} ethyl) amine] -1, 2,3,4-tetrahydroacridine;

9 - [(3- {4 - [(5,6-dimethoxydandan-2-yl) methyl] piperidine-1-yl} propyl) amino] -1, 2,3,4-tetrahydroaccridine ; 6-chloro-9 - [(3- {4 - [(5,6-d ¡methox¡indan-2-yl) methyl] piperidin-1-yl} propyl) amino] -

1, 2,3,4-tetrahydroacridine;

9 - [(2- {4 - [(5,6-dimethoxy-1 -oxoindan-2-yl) methyl] pperidin-1-yl} ethyl) amino] -1, 2,3,4- tetrahydroacridine;

6-Chloro-9 - [(2- {4 - [(5,6-dimethoxy-1-oxoindan-2-1) methyl] piperidin-1-yl} ethyl) amino] - 1, 2,3 , 4-tetrahydroacridine;

9 - [(3- {4 - [(5,6-dimethoxy-1-oxoindan-2-yl) methyl] pperidin-1-l} propyl) amino] -1, 2,3,4 - tetrahydroacridine; Y

6-chloro-9 - [(3- {4 - [(5,6-dimethoxy-1-oxoindan-2-yl) methyl] piperidine-1-yl} propyl) amino] -

1, 2,3,4-tetrahydroacridine.

Another aspect of the present invention relates to a process for the preparation of compounds of formula (I), according to Scheme I. which comprises reacting an intermediate of formula (II) with an intermediate of formula (III), wherein the radicals and variables are as defined above for the corresponding compounds, and Rg is a radical selected from the group consisting of CF ₃ , (CrC ₄ ) -alkyl, phenyl, and phenyl mono- or disubstituted by a radical selected from (Ci- C ₄ ) -alkyl, halogen and nitro; n is an integer from 3 to 5; and r is an integer from 2 to 5. When a pharmaceutically acceptable salt is desired, it is obtained by treatment with the corresponding acid. A preferred acid is HCI.

Preferably, the sulfonate -OSO ₂ R9 is selected from mesylate (R ₉ = -CH ₃ ), tosylate (R ₉ = -C ₆ H ₄ -P-CH ₃ ), besylate (R ₉ = -C ₆ H ₅ ) and triflate (R ₉ = -CF ₃ ), with mesylate being the most preferred.

The intermediates of formula (III) can be prepared by reacting a derivative of the acridine of formula (V) with an alkanolamine of formula (Vl), followed by reacting the hydroxyl group of the compound obtained with a sulfonyl chloride to give the corresponding sulfonate , according to Scheme II. where the radicals and variables have the values defined before.

The intermediates of formula (V) are either known in the art or are easily prepared by analogy with those known in the art. The intermediates (II) can be obtained by debenzylation of donepezil (R ₆ = R ₇ = OMe; R ₅ = R ₈ = H; X = CO; s = 1) or the corresponding analogs of donepezil.

The compounds of formula (I) can also be obtained through the procedure indicated in Scheme (III). which comprises reacting an intermediate of formula (VII) with an intermediate of formula (V).

The intermediates of formula (VII) can be prepared by conventional methods from intermediates of formula (II). Scheme

Another aspect of the present invention relates to a pharmaceutical composition containing a therapeutically effective amount of a compound of formula (I), or a pharmaceutically acceptable salt thereof, or a solvate thereof, including any stereoisomer or mixture of stereoisomers, together with appropriate amounts of pharmaceutical excipients or carriers.

Example 17 illustrates that the compounds of the present invention are potent AChE inhibitors (of bovine or human erythrocytes), showing inhibitory concentrations, expressed as IC5 ₀ (nM), which are in the range of 0.09-5 nM, evaluated by the method described by Ellman et al. The IC50 inhibitory concentrations (nM) of these compounds are considerably lower than those of chlorotacrine or donepezil. Compared with the results of the heterodimers described in WO 2004/032929, also evaluated by the same method of Ellman et al., The inhibitory concentrations CI5 ₀ (nM) of the compounds of the present invention are also considerably inferior. Consequently, these compounds are useful for the treatment of Alzheimer's disease with advantages over those known in the art.

In addition to the AChE inhibitory activity, the inventors have found that the compounds of the present invention also inhibit butyrylcholinesterase (BChE), which may represent an advantage over other anti-Alzheimer's agents known in the art. Recent tests have shown that, in patients with advanced Alzheimer's disease, AChE activity is greatly reduced in specific regions of the brain, while BChE activity increases (cf. Giacobini, E., Neurochem. Res 2003, vol. 28, pp. 515-522). The increasing importance of BChE in the hydrolysis of the acetylcholine neurotransmitter, as the AChE / BChE ratio gradually decreases in these patients, makes the inhibition of BChE an important target in the search for new anti-Alzheimer's agents. Compared with chlorotacrine or donepezil, as well as with the heterodimers described in WO 2004/032929, the compounds of the present invention show considerably lower Cl ₅₀ (nM) inhibitory concentrations against BChE (from human serum).

Thus, a further aspect of the present invention refers to the use of the compounds of formula (I), or a pharmaceutically acceptable salt thereof, or a solvate thereof, including any stereoisomer or mixture of stereoisomers, for the preparation of a medicine for the prophylactic and / or therapeutic treatment of Alzheimer's disease in mammals, including humans. The invention is also related to a method for the treatment or prophylaxis of a mammal, including a human being, who suffers or is susceptible to suffering from Alzheimer's disease. Said method comprises administering to said patient a therapeutically effective amount of a compound of formula (I) defined above, or a pharmaceutically acceptable salt thereof, or a solvate thereof, including any stereoisomer or mixture of stereoisomers, together with excipients or Pharmaceutical carriers

For those skilled in the art, other objects, advantages and characteristics of the invention will emerge partly from the description and partly from the practice of the invention. Throughout the description and claims Ia word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. The summary of this application is incorporated here by reference. The following examples are provided by way of illustration, and are not intended to be limiting of the present invention.

EXAMPLES

General procedure for the reaction of Q-chloro-I ^ .SΛ-tetrahydroacridine or 6,9-dichloro-1, 2,3,4-tetrahydroacridine with ω-amino-1-alcohols.

A mixture of 9-chloro-1, 2,3,4-tetrahydroacridine or 6,9-dichloro-1, 2,3,4-tetrahydroacridine (1 mmol) and excess amino alcohol (3 mmol) in pentanol (1 mL / mmol tetrahydroacridine) was heated at reflux under magnetic stirring for 18 h. The resulting mixture was cooled to room temperature, diluted with CH ₂ CI ₂ (3.5 mL / mmol) and washed with aqueous NaOH solution (10%, 3.5 mL) and water (2 x 3 mL / mmol). The organic phase was dried with Na 2 SO ₄ anhydrous, filtered and concentrated under vacuum giving an oily residue. Excess aminoalcohol and solvent was removed from the residue by distillation in a rotary microdestilador at 85 ⁰ C / 0.8 Torr to give the product as a replacement light brown solid residue. The analytical samples of the hydrochlorides were prepared as follows: The 9- (ω-hydroxyalkylamino) tetrahydroacridine (1 mmol) was dissolved in methanol (10 mL), the solution was filtered through a 0.45 μm PTFE filter, and treated with an excess of methanolic HCI solution (3 mmol / mmol) and the resulting solution was concentrated to dryness in vacuo. The solid was recrystallized from a methanol / ethyl acetate mixture in the ratio 1: 4 (5 mL / mmol). The solid was isolated by filtration and dried at 80 ⁰ C / 30 Torr for 48 h to give the hydrochloride of Ia 9- (ω-hydroxyalkylamino) tetrahydroacridine as a solid light brown.

The structure of the intermediates and compounds of the following Examples have been assigned by ¹ H-NMR (500 MHz, CD ₃ OD or CDCI ₃ ) and ¹³ C-NMR (100.6 MHz, CD ₃ OD or CDCI ₃ ). Example 1: 9-r (2-hydroxetl) aminol-1, 2,3,4-tetrahydroacridine hydrochloride

This compound was obtained by the general method described above: from 9-chloro-1, 2,3,4-tetrahydroaccrine (3.00 g, 13.8 mmol) and 2-aminoethanol (2.49 ml_, 40.6 mmol) 9 - [(2-hydroxyether) amino] -1, 2,3,4-tetrahydroacrylate (3.07 g, 92% base yield) was obtained: TLC (silica gel plate), R _f = 0.38 (25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the 9: 1: 0.1 ratio). From this compound (239 mg, 0.99 mmol), the corresponding hydrochloride analytical sample (215 mg, 78% yield) was obtained: mp 184-185 ⁰ C (MeOH / AcOEt); IR (KBr), v (cm ^{~ 1} ): 3700-2400 (max. At 3358, 3142, 3058, 3016, 2938, 2872; OH, ⁺ NH and CH st), 1633, 1592, 1577, 1524, 1477, 1447, 1412, 1375, 1352, 1324, 1296, 1253, 1181, 1160, 1057, 986, 946, 869, 831, 779, 758, 706, 680.

Example 2: 6-Chloro-9-I-2-hydroxetl) amine-1, 2,3,4-tetrahydroacryrin hydrochloride

This compound was obtained by the general method described above: from 6,9-dichloro-1, 2,3,4-tetrahydroacridine (3.00 g, 11.9 mmol) and 2-aminoethanol (2.16 ml_, 35.9 mmol) 6-chloro-9 - [(2 ~ hydroxyethyl) amino] -1, 2,3,4-tetrahydroacridine (3.16 g, 98% base yield) was obtained: TLC (gel plate silica), R _f = 0.42 (CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio 9: 1: 0.1). From the above compound (150 mg, 0.54 mmol), the corresponding hydrochloride analytical sample (149 mg, 88%) was obtained yield): mp 221-222 ⁰ C (MeOH / AcOEt); IR (KBr), v (crrf ¹ ): 3600-2400 (max. To 3372, 3291, 3136, 3052, 3009, 2939, 2872, 2784; OH, ⁺ NH and CH st), 1632, 1588, 1573, 1518 , 1455, 1365, 1351, 1317, 1291, 1254, 1180, 1084, 1072, 1055, 952, 918, 886, 818, 759, 680, 616.

Example 3: 9-f (3-hydroxypropyaminol-1, 2,3,4-tetrahydroacrylene hydrochloride.

This compound was obtained by the general method described above: from 9-chloro-1, 2,3,4-tetrahydroacridine (1.12 g, 5.14 mmol) and 3-amino-1-propanol (1,16 ml_, 15.2 mmol) 9 - [(3-hydroxypropyl) amino] -1, 2,3,4-tetrahydroacridine (1.25 g, 95% base yield) was obtained: TLC (gel plate silica), R _f = 0.27 (CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio 9: 1: 0.1). From the above compound (371 mg, 1.45 mmol), the corresponding hydrochloride analytical sample (340 mg, 83% yield) was obtained: mp 125-126 ⁰ C (MeOH / AcOEt); IR (KBr), v (crτT ¹ ): 3700-2400 (max. At 3283, 3145, 3052, 3020, 2938, 2868, 2806, 2773; OH, ⁺ NH and CH st), 1632, 1582, 1528, 1477 , 1461, 1448, 1414, 1348, 1323, 1278, 1260, 1180, 1167, 1085, 1071, 1038, 993, 979, 917, 883, 864, 828, 798, 781, 755, 706, 682, 607.

Example 4: 6-Chloro-9 - [(3-hydroxypropyl) amine-1, 2,3,4-tetrahydroacryrin hydrochloride

This compound was obtained by the general method described above: from 6,9-dichloro-1, 2,3,4-tetrahydroacridine (3.00 g, 11.9 mmol) and 3-amino-1- propanol (2 , 16 mL, 28.2 mmol) 6-chloro-9 - [(3-hydroxypropyl) amino] -1, 2,3,4-tetrahydroacridine (1.25 g, 36% base yield) was obtained: TLC ( silica gel plate), R _f = 0.32 (CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio 9: 1: 0.1). From the above compound (334 mg, 1.15 mmol), the corresponding hydrochloride analytical sample (270 mg, 72% yield) was obtained: mp 164-165 ⁰ C (MeOH / AcOEt); IR (KBr), v (cnT ¹ ): 3500-2400 (max. To 3353, 3314, 3263, 3131, 3051, 3014, 2936, 2907, 2875, 2845, 2803; OH, ⁺ NH and CH st), 1630 , 1572, 1526, 1467, 1436, 1421, 1356, 1341, 1322, 1253, 1245, 1184, 1102, 1068, 1056, 948, 881, 818, 760, 726, 709.

General procedure for the mesylation of 9- (ω-hydroxyalkylamino) -1, 2,3,4-tetrahydroacridines.

To a cold (-10 ⁰ C, ice bath-salt) of the 9- (ω hidrox¡alquilamino ~) -1, 2,3,4-tetrahidroacr¡dina (1 mmol) and triethylamine (1, 7 mmol ) in anhydrous CH ₂ CI ₂ (6 mL / mmol) methanesulfonyl chloride (1.5 mmol) was added dropwise and the mixture was stirred for 30 min at that temperature. The mixture was concentrated in vacuo, the residue was dissolved in

CH ₂ CI ₂ (3 mL / mmol) and the organic solution was washed with aqueous NaOH solution (10%, 2 x 3 mL / mmol) until the aqueous phase remained basic (pH> 10), dried with Na ₂ Anhydrous SO ₄ and concentrated in vacuo to give the corresponding mesylate as a brown oily residue. The analytical samples of the mesylates were obtained by treating the oily product with ethyl acetate.

Example 5: 9 - [(2-methanesulfonyloxyl) amino1-1, 2,3,4-tetrahydroacridine.

This compound was obtained by the general method described above: from 9- (2-hydroxyethylamino) -1, 2,3,4-tetrahydroacridine (2.15 g, 8.87 mmol), 9 - [(2 -methanesulfonyloxyethyl) amino] -1, 2,3,4-tetrahydroacridine (3.13 g, quantitative yield): TLC (silica gel plate), R _f = 0.67 (25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the ratio 9: 1: 0.1). IR (NaCI), v (crrf ¹ ): 3391, 3339 (NH st), 3092, 3069, 2936, 2866 (CH st), 1638, 1586, 1524, 1493, 1440, 1413, 1352, 1331, 1194, 1178 , 1051, 771.

Example 6: 6-Chloro-9-r (2-methanesulfonyloxyl) aminol-1, 2,3,4-tetrahydroacridine hydrochloride

This compound was obtained by the general method described above: from 6- chloro-9- (2-hydroxyethylamino) -1, 2,3,4-tetrahydroacridine (2.95 g, 10.7 mmol), 6 was obtained -chloro-9 - [(2-methanesulfonyloxyethyl) amino] -1, 2, 3,4-tetrahydroacridine (3.72 g, 98% yield): TLC (silica gel plate), R _f = 0.63 ( CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio 9: 1: 0.1). In this case, an analytical sample of the hydrochloride was prepared as follows: the above compound (2.59 g, 7.3 mmol) was dissolved in methanol (20 ml_), the solution was filtered through a 0.45 μm PTFE filter , was treated with excess methanolic HCI solution (1.7 M, 14 ml_) and the solution was concentrated to dryness in vacuo. The solid (2.65 g) was recrystallized from methanol (10 mL). After filtration, the solid was dried at 80 ⁰ C / 30 Torr for 48 h to give the corresponding hydrochloride as a white solid (2.30 g, 81% yield), mp: 149- 150 ⁰ C (MeOH); IR (KBr), v (ατT ¹ ): 3700-2500 (max. 3426, 3234, 3114, 3012, 2925, 2798; ⁺ NH and CH st), 1630, 1606, 1582, 1572, 1487, 1463, 1452 , 1409, 1374, 1354, 1161, 1094, 1030, 1002, 983, 933, 916, 874, 804, 762, 733, 671.

Example 7: 9-í (3-methanesulfonyloxypropyl) aminol-1, 2.3.4-tetrahydroacridine

This compound was obtained by the general method described above: from 9- (3-hydroxylpropylamine) -1, 2,3,4-tetrahydroaccrine (433 mg, 1,68 mmol) , 9 - [(3-methanesulfonyloxypropyl) amino] -1, 2,3,4-tetrahydroacridine (565 mg, quantitative yield) was obtained: TLC (silica gel plate), R _f = 0.95 (CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio 9: 1: 0.1). IR (NaCI), v (cm ^'1 ): 3282 (NH st), 3100, 3065, 2935, 2864 (CH st), 1639, 1586, 1524, 1501, 1448, 1418, 1352, 1332, 1194, 1174, 1041, 964, 931, 767, 733.

Example 8: 6-Chloro-9-y (3-methanesulfonloxpropyl) amino1-1, 2,3,4-tetrahydroacridine

This compound was obtained by the general method described above from 6- chloro-9- (3-hydroxypropylamino) -1, 2,3,4-tetrahydroacridine. The crude product was used in the next stage without further purification (see examples 12 and 16).

General procedure for the coupling of 9- (ω- methanesulfonloxyalαuylamino) -1, 2,3,4-tetrahydroacryridines v 5,6-dimethoxy-2-f (4- piperidyl) met¡π¡ndano or 5, 6-d¡metoxi-2-r (4-p¡per¡dil) metiπindan-1 -ona

A solution of mesylate (1 mmol), the piperidine derivative (1 mmol) and anhydrous triethylamine (2.5 mmol) in DIVISO (8 ml_) was heated at 85 ⁰ C for 48 h. The solution was allowed to temper and was concentrated in vacuo. The brown oily residue was treated with aqueous NaOH (2 N, 25 µL) and extracted with CH ₂ CI ₂ (3 x 35 mL). The combined organic extracts were washed with water (5 x 40 mL) and brine (2 x 30 mL), dried over anhydrous Na ₂ Sθ ₄ and concentrated in vacuo to give an oily residue that was subjected to column chromatography (gel silica 35-70 μm, mixtures CH ₂ CI ₂ / methanol / 25% aqueous NH ₄ OH as eluent). The product was transformed into the corresponding dihydrochloride as follows: A solution of the base (1 mmol) in methanol (40 ml_) was filtered through a 0.45 µm PTFE PTFE filter and treated with excess methanolic HCI solution (5 mmol). The solution was concentrated to dryness in vacuo and the solid residue was recrystallized from methanol (20 mL). The solid was filtered and dried at 80 ⁰ C / 30 Torr for 48 h.

Example 9: 9-í (2-f4-r (5.6-dimethoxindan-2-ihmet¡np¡per¡d¡n-1-l> etl) - aminol-1,2,3,4-tetrahydroacridine dihydrochloride

This compound was obtained by the general method described above from 9- (2-methanesulfonyloxyethylamino) -1,2,3,4-tetrahydroacrylene (365 mg, 1,14 mmol) and 4 - [(5, 6-dimethoxyindan-2-yl) methyl] pperidine (306 mg, 11.11 mmol). By eluting with a mixture of 25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the 99: 1: 0.1 ratio, 9 - [(2- {4 - [(5,6-dimethoxyindan- 2-yl) methyl] piperine-1-yl} ethyl) amino] -1, 2,3,4-tetrahydroaccrine (191 mg, 34% yield) as a slightly brown solid: TLC (gel plate silica), R _f = 0.68 (CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio 90: 10: 0.1). The analytical sample of the dihydrochloride was obtained in the manner described in the general method: from the base (114 mg, 0.23 mmol) the corresponding dihydrochloride monohydrate was obtained as a pale yellow solid (48 mg, 35% yield), mp 254 -255 ⁰ C (methanol). IR (KBr), v (cnrT ¹ ): 3700-2400 (max. To 3399, 3245, 2928, 2834; ⁺ NH and CH st), 1635, 1613, 1584, 1524, 1504, 1452, 1440, 1310, 1226 , 1181, 1095, 989, 953, 850, 758, 677.

Example 10: 6-Chloro-9-f (2- (4-r (5.6-d ¡methox¡indan-2-yl) metillp¡peridin-1- 1) ethyl) aminol-1.2.3.4-tetrahydroacryl dihydrochloride

This compound was obtained by the general method described above from 6- chloro-9- (2-methanesulfonloxyethylamino) -1, 2,3,4-tetrahydroacridine (386 mg, 1, 20 mmol) and 4 - [( 5,6-dimethoxyindan-2-yl) methyl] piperidine (300 mg, 1.09 mmol). By eluting with a mixture of 25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the 99: 1: 0.1 ratio, 6-chloro-9 - [(2- {4 ~ [(5,6- dimethoxyindan-2- yl) methyl] pperperdin-1-yl} etl) amino] -1, 2,3,4-tetrahydroaccrine (165 mg, 28% yield) as a slightly brown solid: TLC ( silica gel plate), R _f = 0.68 (25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the ratio 90: 10: 0.1). The analytical sample of the dihydrochloride was obtained as described in the general method: from the base (165 mg, 0.31 mmol), the corresponding hydrated dihydrochloride was obtained as a slightly yellow solid (80 mg, 40% yield), mp 159-160 ⁰ C (methanol). IR (KBr), v (crn ^"1 ): 3700- 2400 (max. 3414, 3259, 3047, 2932, 2835; ⁺ NH and CH st), 1631, 1585, 1504, 1451, 1362, 1315, 1252, 1223, 1181, 1094, 949, 886, 839, 760.

Example 11: 9-í (3- (4-r (5.6-dimethoxinin-2-iπmet¡πpiper¡d¡n-1-yl | prop¡πam¡nol- 1.2,3.4-tetrahydroacryl dihydrochloride.

This compound was obtained by the general method described above from 9- (3-methanesuIphonyloxypropylamino) -1, 2,3,4-tetrahydroacridine (294 mg, 0.88 mmol) and 4 - [(5,6- dmethoxyindan-2-yl) methyl] piperidine (242 mg, 0.88 mmol). By eluting with a mixture of 25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the 99: 1: 0.2 ratio, 9 - [(3- {4 - [(5,6-dimethoxynedin) 2-yl) methyl] piperidin-1- yl} propyl) amino] -1, 2,3,4-tetrahydroacridine (81 mg, 18% yield) as a pale yellow solid: TLC (silica gel plate), R _f = 0.66 (CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio 90: 10: 0.1). The analytical sample of the dihydrochloride was obtained as described in the general method: from the base (81 mg, 0.16 mmol), the corresponding hydrated dihydrochloride was obtained as a pale yellow solid (95 mg, 93% yield), mp 184-185 ⁰ C (methanol). IR (KBr), v (crrf ¹ ): 3660-2200 (max. To 3370, 2924, 2854, 2706; ⁺ NH and CH st), 1634, 1588, 1522, 1503, 1455, 1363, 1308, 1249, 1117 , 1182, 1093, 1033, 987, 947, 844, 759, 678.

Example 12: e-chloro-g-ffó ^ -rfδ.e-dimethoxyindan ^ -iDmetiπpiperidin-i- I) propyl) amine1-1, 2,3,4-tetrahydroacridine dihydrochloride

.2Cl-

At a cold solution (-10 ⁰ C ₁ ice-salt bath) of 6-chloro-9- (3- hydroxypropylamine) -1, 2,3,4-tetrahydroacryphane (1.50 g, 5.16 mmol) and triethylamine (1.20 mL, 8.6 mmol) in anhydrous CH ₂ CI ₂ (35 mL), methanesulfonyl chloride (0.65 mL, 8.40 was added dropwise) mmol) and the mixture was stirred at that temperature for 30 min. The mixture was concentrated in vacuo, the residue was dissolved in CH ₂ CI ₂ (50 mL) and the organic solution was washed with saturated aqueous NaHCO ₃ solution (3 x 50 mL) until the aqueous phase remained basic (pH = 10 ), dried with anhydrous Na ₂ SO ₄ , and concentrated in vacuo to give a brown oily residue (1.90 g), which contained the corresponding mesylate, which was used as such in the next step. Part of this product (368 mg, 1.0 mmol) was reacted with 4 - [(5,6-dimethoxydan-2-yl) methyl] piperidine (271 mg, 0.98 mmol) following the general method described above. By eluting with a mixture of 25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the 97: 3: 0.2 ratio, 6-chloro-9 - [(3- {4 - [(5, 6-dimethoxyindan-2- yl) methyl] piperidin-1-yl} propyl) amino] -1, 2,3,4-tetrahydroacryrin (210 mg, 39% yield) as a pale brown solid: TLC ( silica gel plate), R _f = 0.49 (25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the ratio 90: 10: 0.1). The analytical sample of the dihydrochloride was obtained as described in the general method: from the base (81 mg, 0.15 mmol), the corresponding hydrated dihydrochloride was obtained as a pale yellow solid (52 mg, 52% yield), mp 173-174 ⁰ C (methanol). IR (KBr), v (crτT ¹ ): 3700-2450 (max. To 3401, 2928; ⁺ NH and CH st), 1630, 1581, 1503, 1463, 1451, 1358, 1309, 1250, 1217, 1182, 1093 , 988, 949, 880, 759.

Example 13: 9-r (2- (4-f (5.6-dimethox¡-1-oxoindan-2-i0metillp¡per¡din-1-yltethyl) amino1-1, 2,3,4-tetrahydroacridine dihydrochloride

This compound was obtained by the general method described above from 9- (2-methanesulfonyloxyethylamino) -1, 2,3,4-tetrahydroacridine (276 mg, 0.86 mmol) and 4 - [(5,6-dimethoxy- 1-oxoindan-2-yl) methyl] piperidine (249 mg, 0.86 mmol). Ai eluting with a mixture of 25% aqueous CH ₂ Cb / MeOH / NH ₄ OH in the ratio 99.5: 0.5: 0.4, 9 - [(2- {4 - [(5,6-dimethoxy-1 -oxoindan-2- 1) methyl] piperidin-1-yl} ethyl) amino] -1, 2,3,4-tetrahydrocrcrine (87 mg, 19% yield) as a pale brown solid: TLC (plate silica gel), R _f = 0.91 (CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio 90: 10: 0.1). The analytical sample of the dihydrochloride was obtained as described in the general procedure: from the base (54 mg, 0.10 mmol), the corresponding hydrated dihydrochloride was obtained as a pale yellow solid (62 mg, 98% yield), mp 190-191 ⁰ C (methanol). IR (KBr), v (cιτf ¹ ): 3700-2400 (max. At 3401, 2928, 2871, 2718; ⁺ NH and CH st), 1685, 1672 (C = O st), 1636, 1588, 1523, 1500 , 1458, 1363, 1317, 1266, 1220, 1120, 1037, 949, 863, 760.

Example 14: 6-Chloro-9-r (2- (4-r (5.6-d¡metox¡-1-oxo¡ndan-2-yl) methypipiperid-1-I) ethyl) amino1-1, 2,3,4-tetrahydroacridine dihydrochloride

This compound was obtained by the general method described above, from 6-chloro-9- (2-methanesulfonyloxyethylamino) -1, 2,3,4-tetrahydroacridine (305 mg, 0.86 mmol) and 4 - [(5 , 6-dimethoxy-1-oxoindan-2-yl) methyl] piperine (248 mg, 0.86 mmol). By eluting with a mixture of 25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the ratio 99.2: 0.8: 0.4, 6-chloro-9 - [(2- {4 - [(5, 6-dimethoxy-1-oxoindan- 2-i) methyl] piperine-1-yl} ethyl) amine] -1, 2,3,4-tetrahydroacryrin (178 mg, 38% yield) as a pale brown solid: CCF (silica gel plate), R _f = 0.94 (CH ₂ CI ₂ / MeOH / NH ₄ OH 25% aqueous in the ratio of 90: 10: 0.1). The analytical sample of the dihydrochloride was obtained as described in the general method: from the base (168 mg, 0.31 mmol), the corresponding hydrated dihydrochloride was obtained as a beige solid (65 mg, 33% yield), mp 222-223 ⁰ C (methanol). IR (KBr) v (crrf ¹ ): 3700-2400 (max. At 3375, 3259, 3125, 3051, 2927, 2854, 2792; ⁺ NH and CH st), 1687 (C = O st), 1633, 1588, 1501, 1456, 1363, 1316, 1266, 1220, 1179, 1121, 1091, 1036, 949, 917, 884, 759.

Example 15: 9-r (3- (4-f (5,6-dimethoxy-1-oxo¡ndan-2-yl) metillpperidin-1- yl> rop¡l) aminol-1, 2,3.4- tetrahydroacridine dihydrochloride

This compound was obtained by the general method described above, from 9- (3-methanesulfonyloxypropylamino) -1, 2,3,4-tetrahydroacridine (80 mg, 0.24 mmol) and 4 - [(5,6-dimethoxy -1-oxoindan-2-yl) methyl] piperine (82 mg, 0.28 mmol). By eluting with a mixture of 25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the ratio 98: 2: 0.5, 9 - [(3- {4 - [(5,6-dimethoxy- 1-oxoindan-2- yl) methyl] pperidin-1-yl} propyl) amino] -1, 2,3,4-tetrahydroacridine (87 mg, 68% yield) as a pale brown solid: TLC (silica gel plate), R _f = 0.46 (25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the 9: 1: 0.1 ratio). The analytical sample of the dihydrochloride was obtained according to the general method: from the base (50 mg, 0.095 mmol), the corresponding hydrated dihydrochloride was obtained as a pale yellow solid (37 mg, 60% yield), mp 198-199 ⁰ C (methanol). IR (KBr), v (cnT ¹ ): 3700-2400 (max. At 3435, 2930, 2706; ⁺ NH and CH st), 1690 (C = O st), 1636, 1590, 1522, 1500, 1458, 1364 , 1316, 1265, 1121, 1036, 759. Example 16: 6-Chloro-9-r (3- (4-r (5.6-dimethox¡-1 -oxo¡ndan-2-Dmetillpiper¡din-1 - hel) propyl) amino1-1, 2,3, 4-tetrahydroacridine dihydrochloride

To a cold (-10 ⁰ C, ice-salt bath) of 6-chloro-9- (3- hidrox¡propilamino) -1, 2,3,4-tetrahidroacrid¡na (1.50g, 5, 16 mmol) and triethylamine (1.20 ml_, 8.6 mmol) in anhydrous CH ₂ CI ₂ (35 ml_), methanesulfonyl chloride (0.65 ml_, 8.40 mmol) was added dropwise and the mixture was stirred at that temperature for 30 min. The mixture was concentrated in vacuo, the residue was dissolved in CH ₂ CI ₂ (50 ml_) and the organic solution was washed with saturated aqueous NaHCO ₃ solution (3 x 50 ml_) until the aqueous phase remained basic (pH = 10 ), dried with anhydrous Na ₂ SO ₄ , and concentrated in vacuo to give a brown oily residue (1.90 g), containing the corresponding mesylate, which was used as such in the next step. Part of this product (506 mg, 1.37 mmol) was reacted with 4 - [(5,6-dimethoxy-1- oxoindan-2-yl) methyl] piperidine (470 mg, 1, 62 mmol ) following the general method described above: by elution with a mixture of 25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the ratio 98: 2: 0.2, 6-chloro-9 - [(3 - {4- [(5,6-Dimethoxy-1-oxoindan-2-1) methyl] piperidine-1-yl} propyl) amino] -1, 2,3,4-tetrahydroacryrin (254 mg, 33 % yield) as a pale brown solid: TLC (silica gel plate), R _f = 0.52 (25% aqueous CH ₂ CI ₂ / MeOH / NH ₄ OH in the 9: 1: 0.1 ratio). The analytical sample of the dihydrochloride was obtained as described in the general method: from the base (254 mg, 0.45 mmol), the corresponding hydrated dihydrochloride was obtained as a pale yellow solid (212 mg, 68% yield), mp 185-186 ⁰ C (methanol). GO

(KBr), v (crrf ¹ ): 3700-2400 (max. At 3402, 3263, 3071, 3039, 2925, 2842; ⁺ NH and CH St) ₁ 1695 (C = O st), 1631, 1608, 1590, 1556, 1501, 1462, 1357, 1313, 1264, 1218, 1124, 1036, 971, 948, 882, 803, 758.

Example 17: Biochemical Studies

The inhibitory activity of AChE was assessed spectrophotometrically at 25 ⁰ C by the method of Ellman (see Ellman et to the., Biochem. Pharmacol. 1961, vol. 7, p. 88), using as substrate AChE from bovine or human erythrocytes and iodide of acetylthiocholine (0.53 mM or 0.27 mM for bovine and human AChE, respectively). The reaction took place in a final volume of 3 mL of 0.1 M phosphate buffer solution pH 8.0, containing 0.025 units of AChE and a 333 μM solution of 5,5'-dithiobis acid (2-nitrobenzoic acid (DTNB) was used ) to produce the yellow anion of 5-thio-2-nitrobenzoic acid The inhibition curves were carried out in triplicate by incubating with at least 12 inhibitor concentrations for 15 min. A triplicate sample without inhibitor was always present to know 100% of AChE activity The reaction was stopped by the addition of 100 µL of 1 mM serine, and the color production was determined at 414 nm. The determinations of the inhibitory activity of the BChE were carried out in a similar manner, using 0.035 BChE units. human serum and 0.56 mM butyrylthiocholine, instead of AChE and acetylthiocholine, in a final volume of 1 mL.

The data from the concentration inhibition inhibitor experiments were calculated by non-linear regression analysis, using the GraphPad Prism program package (GraphPad Software; San Diego, USA), which gives estimates of IC ₅₀ (drug concentration which produces 50% inhibition of the enzyme activity). The results are expressed as mean ± SEM of at least 4 experiments performed in triplicate. DTNB, acetylthiocholine, butyrylthiocholine, and the enzymes were purchased from Sigma and the serine from Fluka. Table 1. Pharmacological data of the new donepezil-tacrine, and tacrine, 6-chlorotacrine and donepezil heterodimers as reference compounds. The values are expressed as mean ± standard error of the mean of at least four experiments. Cl ₅₀ (nM) inhibitory concentration of AChE activity (of bovine or human erythrocytes) or BChE (of human serum).

Claims

1. Compound of formula (I), or a pharmaceutically acceptable salt thereof, or a solvate thereof, including any stereoisomer or mixture of stereoisomers, wherein:

(I)

Ri. R2, R3, and R4 are radicals independently selected from the group consisting of H, F, Cl, Br, CF ₃ , (Ci ~ C ₄ ) -alkyl, (Ci-C ₄ ) -alkoxy, and nitro ;

Rδ, Re, R7, and Re are radicals independently selected from the group consisting of H and (Ci-C ₆ ) -alkoxy; n is an integer from 3 to 5; r is an integer from 2 to 5; s is an integer from 1 to 5; Y

X is a biradical selected between CO and CH ₂ .

2. Compound according to claim 1, wherein:

R-i, R2, R3, and R4βon radicals independently selected from the group consisting of H, F, Cl and Br;

R5, R _Θ , R7 and R _δ are radicals independently selected from the group consisting of H and methoxy; and s is 1.

3. Compound according to claim 2, wherein R ₂ is selected from H and Cl; RL R ₃ , R ₄ , R ₅ and Rs are H; RQ and R ₇ are methoxy; n is an integer from 3 to 4; and r is an integer from 2 to 3.

4. Compound according to claim 3, which is 9 - [(2- {4 - [(5,6-dimethoxy-ndan-2-l) methyl] pperidin-1-yl} ethyl) amino] -1 , 2,3,4-tetrahydroacridine.

5. Compound according to claim 3, which is 6-chloro-9 - [(2- {4 - [(5,6-dimethoxyindan-2-yl) methyl] piperine-1-yl} ethyl) amine ] -1, 2,3,4-tetrahydroaccrine.

6. Compound according to claim 3, which is 9 - [(3- {4 - [(5,6-dimethoxydan-2- yl) methyl] piperidin-1-yl} propyl) amino] -1, 2,3,4-tetrahydroacridine.

7. Compound according to claim 3, which is 6-chloro-9 - [(3- {4 - [(5,6-dimethoxyndan-2-yl) methyl] piperidin-1-yl} propyl) amino ] -1, 2,3,4-tetrahydroaccrine.

8. Compound according to claim 3, which is 9 - [(2- {4 - [(5,6-dimethox-1-oxoindan-2-yl) methyl] pperidin-1-yl} ethyl) amine] -1, 2,3,4-tetrahydroaccrine.

9. Compound according to claim 3, which is 6-chloro-9 - [(2- {4 - [(5,6-dimethoxy-1-oxoindan-2-yl) methyl] piperidine-1-¡ l} ethyl) amino] -1, 2,3,4-tetrahydroacridine.

10. Compound according to claim 3, which is 9 - [(3- {4 ~ [(5,6-dimethox-1-oxoindan-2-yl) methyl] piperidin-1-yl} propyl) amino] -1 , 2,3,4-tetrahydroaccrine.

11. Compound according to claim 3, which is 6 ~ chloro-9 - [(3- {4 - [(5,6-dimethoxy-1-oxoindan-2-yl) methyl] pperidin-1-yl } propyl) amino] -1, 2,3,4-tetrahydroacridine.

12. Compound according to any of claims 1-11, wherein the pharmaceutically acceptable salt is hydrochloride or dihydrochloride.

13. Process for the preparation of a compound as defined in any of claims 1-12, which comprises reacting an intermediate of formula (II)

(II)

with an intermediate of formula (III),

and optionally treating with the pharmaceutically acceptable acid to form the corresponding salt;

where R ₁ , R ₂ , R3, R4, R5, Rδ, R7, Rs, n, r, and X have the values that have been defined in the corresponding compound claim; and R ₉ is a radical selected from the group consisting of CF ₃ , (C ₁ -C ₄ ) ^ IqUiIo, phenyl, and phenyl mono- or disubstituted by a radical selected from (CiC ^ -alkyl, halogen and nitro.

14. Process for the preparation of a compound as defined in any of claims 1-12, which comprises reacting an intermediate of formula (VII),

with an intermediate of formula (V) ₁

and optionally treating with a pharmaceutically acceptable acid to form the corresponding salt;

where R ₁ , R ₂ , R ₃ , R ₄ , R5, Re, R7, Rs, n, r, s and X have the values defined in the corresponding compound claim.

15. Use of the compounds defined in any of claims 1-12, for the preparation of a medicament for the treatment and / or prevention of Alzheimer's disease in a mammal, including a human being.

16. Pharmaceutical composition comprising a therapeutically effective amount of a compound defined in any of claims 1-12, together with the appropriate amounts of pharmaceutically acceptable excipients or carriers.