ES2819309B2 - Nicotinic agonist and antioxidant compounds for the treatment of neurodegenerative diseases - Google Patents

Description

DESCRIPTION

NICOTINE AGONIST AND ANTIOXIDANT COMPOUNDS FOR

TREATMENT OF NEURODEGENERATIVE DISEASES

FIELD OF THE INVENTION

The present invention is mainly framed in the pharmaceutical sector with applications aimed at the prevention and / or treatment of diseases and any type of condition or damage that involves abnormal activity of nicotinic receptors or that occurs with high levels of oxidative stress and, specifically , in the identification of chemical compounds useful in the preventive and / or therapeutic treatment of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD), multiple sclerosis (MS) or stroke.

BACKGROUND OF THE INVENTION

Aging is related to the progressive accumulation of physiological changes due to genetic mutations, epigenetic and metabolic changes, which lead to a greater susceptibility to age-related diseases.

The population aged 65 and over continues to increase with the consequent increase in the number of patients with Alzheimer's and other dementias. In 2016, these diseases were the fifth leading cause of death worldwide in 2016, accounting for 2.1 million deaths (3.7%) (Organization, 2018a ). In 2018, the number of people suffering from AD and other dementias was estimated at 50 million, and a prevalence of 75 million by 2030 and 152 million by 2050 is estimated (Organization, 2018b ).

AD is a neurodegenerative disease related to aging. It is fundamentally characterized by loss of memory and cognitive functions, mainly due to the death of cholinergic neurons in brain regions associated with attentional, spatial and episodic memory, such as the neocortex, the temporal lobes and the hippocampus (Mesulam, 2013 , J Comp Neurol, 521: 4124-44). In addition to this synaptic loss, other pathophysiological features are the appearance of intracellular neurofibrillary tangles, which contain the hyperphosphorylated tau protein; senile extracellular plaques, composed mainly of p-amyloid peptide aggregates; mitochondrial dysfunction; deregulation of Ca2 + homeostasis; oxidative stress (Sanabria-Castro et al., 2017 , Annals of Neurosciences, 24: 46-54) and chronic inflammation (Glass et al., 2010, Cell, 140: 918-34).

From a chemical point of view, free radicals are species that contain one or more highly reactive unpaired electrons, capable of oxidizing molecules present in the environment (Halliwell, 2015 , eLS). From a biological point of view, free radicals of O2, known as reactive oxygen species (ROS) or N2, reactive nitrogen species (ERN)), are products of physiological metabolism (Di Carlo et al., 2012 , Free Radical Research, 46: 1327-38). The main source of ROS is the electronic transport chain for the generation of ATP in the mitochondria. Therefore, strict control of free radical homeostasis is necessary. However, during aging, the mitochondrial balance of ROS is deregulated, inducing exacerbated oxidative damage. The aging process is associated with the accumulation of free radicals, generating an imbalance between the pro-oxidant and antioxidant species. The free radicals generated damage the mitochondrial DNA causing accumulated mutations in the genes of the electronic transport chain, resulting in an overproduction of ROS.

Neurotransmission requires large amounts of energy, therefore the brain consumes a large amount of oxygen. This fact, together with the low effectiveness of the antioxidant system and the high concentration of lipids in neurons, makes the brain even more susceptible to oxidative damage (Salim, 2017 , J Pharmacol Exp Ther, 360: 201-05). Considering aging the main risk factor for AD, oxidative stress and mitochondrial dysfunction are considered early contributors to the disease. In fact, there is evidence of oxidative markers such as RNA-derived oxidized nucleosides or lipid peroxidation, which appear before neurofibrillary tangles formation or p-amyloid (Ap) deposition (Nunomura et al., 2001 , Journal of Neuropathology & Experimental Neurology, 60: 759-67).

As already mentioned, one of the main characteristics of AD and the one responsible for its most notable symptoms is the decrease in cholinergic activity. The nicotinic acetylcholine receptor a7 (nAChR-a7) participates in cholinergic neurotransmission, being mediators of cholinergic signaling involved in the modulation of memory and cognitive functions. However, in AD its expression and function is altered, leading to the activation of pro and anti-survival pathways depending on the stage of the disease, the type of cell involved or the ligand used.

The nAChR-a7 is one of the most predominant nAChRs expressed in the brain, along with a4p2. NAChR-a7 are found in neurons, outside the synaptic cleft in the pre and post-synaptic locations where they promote neuronal excitability and neurotransmitter release, as well as extra-synaptic, participating in non-excitable communication (Dineley and col., 2015 , Trends Pharmacoí Sci, 36: 96-108). They are also expressed in non-neuronal cells, including astrocytes and microglia, where they are involved in inflammation and neuroprotection (Shytle et al., 2004 , Journal of Neurochemistry, 89: 337-43) (Egea et al., 2015 , Biochem Pharmacoí, 97: 463-72).

The nAChR-a7 is unique within the nAChR family in that it has a dual ionotropic and metabotropic nature. As a transmembrane cation channel it initiates three types of calcium signals. In the first place, the direct influence due to its high permeability to Ca2 +; second, indirectly through activation of voltage-gated calcium channels (VDCC) and, finally, calcium-induced calcium release (ICRC) from the endoplasmic reticulum (Shen et al., 2009 , Acta Pharmacoí Sin, 30: 673-80). All of them are involved in neurotransmission, however, the induced Ca2 + signal may lead to the activation of neuroprotective mechanisms (Parada et al., 2010 , Free Radic Bioí Med, 49: 1815-21). On the other hand, the metabotropic pathway can trigger neuroprotective signaling cascades, such as the stimulation of nAChR-a7 with nicotine, which induces the activation of the PI3K / Akt pathway (Shaw et al., 2002 , J Bioí Chem, 277 : 44920-4).

Patent documents WO2008 / 058096, WO2014 / 160783, WO2010 / 126605, WO2010 / 046710, WO2012 / 149478, WO2013 / 067036, WO2013 / 132124, WO2018 / 102885 propose different treatment options for neurodegenerative diseases based on one or more chemical compounds and / or natural products whose therapeutic target is the modulating activity of nicotinic receptors in the same sense.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to the use of compounds with the structure 1- (2- (1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea and 1- (2- (1 H-indole-3 -il) ethyl) -3- (quinuclidin-3-yl) urea with modulating capacity of nicotinic receptors and free radical scavenging capacity that exert, as a consequence of both properties, neuroprotective effects.

The present invention describes, for the first time, the inclusion in a single molecule of the modulating capacity of nicotinic receptors in addition to including the sequestrant of free radicals due to the combination of substructures from which the proposed chemical structure has been obtained. Furthermore, the compounds object of the present invention possess neuroprotective capacity, which is why they can be potentially useful in the prevention and / or treatment of neurodegenerative diseases. More specifically, the object of the present invention is to provide new compounds useful as active ingredients of a medicine, which allow the prevention and / or treatment of neurodegenerative diseases.

Therefore, in one aspect, the invention relates to a compound of formula (I), its salts, prodrugs or solvates. Said compound of formula (I) can be used in the treatment of neurodegenerative diseases and / or diseases that are related to a dysregulation of the activity of nicotinic receptors in relation to the neuroprotection associated with their modulation in different neurodegenerative diseases.

In another aspect, the invention relates to a pharmaceutical composition comprising a compound of formula (I), or a salt, a prodrug or a solvate thereof, and a pharmaceutically acceptable carrier.

In another aspect, the invention protects the use of said compound of formula (I), or its pharmaceutically acceptable salts, prodrugs or solvates, in the preparation of a pharmaceutical composition for the prevention or treatment of neurodegenerative diseases.

In the context of the present invention, the following terms have the meaning detailed below:

When the term "independently selected" is used, the substituents to which it refers (eg R groups, such as the R1, R2, R3, R4, R5, R6 or X or Y or Z groups or variables such as "n") are Groups can be identical or different, or where appropriate when specified.

The term "alkyl" refers to a straight or branched hydrocarbon chain radical consisting only of carbon and hydrogen atoms that do not contain unsaturations, having from one to eight carbon atoms, and which is linked to the rest of the molecule by a single bond. . Preferably, it refers to a straight or branched aliphatic chain radical having between 1 and 6, preferably between 1 and 3 ("C1-3 alkyl") carbon atoms, and which is linked to the rest of the molecule by a single bond. This term includes, for example and in a non-limiting sense, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-pentyl, etc. The Alkyl radicals may be optionally substituted by one or more substituents independently selected from the group consisting of halogens, hydroxyl, alkoxides, carboxy, cyano, carbonyl, acyl, alkoxycarbonyl, amino, nitro, mercapto, and alkylthio.

The term "alkoxy" refers to a group -O-alkyl, where alkyl is as previously defined. Preferably alkoxy is methoxy.

The term "halogen" refers to bromine, chlorine, iodine, or fluorine. Preferably halogen is fluorine or chlorine or bromine.

The term "haloalkyl" refers to an alkyl radical, as previously defined, that is substituted by one or more halogens, as also previously defined, including, for example, and in a non-limiting sense, trifluoromethyl, trichloromethyl, 2,2,2, -trifluoroethyl, 1-fluoromethyl-2-fluoroethyl, etc.

The term "alkoxycarbonyl" refers to a radical of formula -C (O) OR where R is an alkyl radical as previously described. Alkoxycarbonyl radicals can include, for example, and in a non-limiting sense, methoxy, ethoxy, propoxy, etc.

The term "cycloalkyl" refers to a saturated or partially saturated mono or polycyclic aliphatic group, having between 3 and 10, preferably between 3 and 6 carbon atoms that is attached to the rest of the molecule via a single bond, including , for example, and in a non-limiting sense, cyclopropyl, cyclobutyl, cyclohexyl, cyclopentyl, etc.

The term "amino" refers to a radical of formula -NH2.

The term "aryl" refers to an aromatic group having between 6 and 18, preferably between 6 and 10 carbon atoms, comprising 1,2 or 3 aromatic nuclei, linked via a carbon-carbon bond or condensed, including for example and in a non-limiting sense phenyl, naphthyl, diphenyl, indenyl, phenanthryl, etc.

The term "heterocycle" refers to a stable 3- to 10-membered ring radical, preferably a 5- or 6-membered ring, consisting of carbon atoms and from one to five heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur. , and which may be partially or fully saturated, or may be aromatic ("heteroaryl"). For the purposes of this invention, the heterocycle may be a monocyclic, bicyclic ring system or tricyclic, which can include fused ring systems. Examples of such heterocycles include, but are not limited to, pyrrolidine, piperidine, piperazine, morpholine, tetrahydrofuran, benzimidazole, benzothiazole, furan, pyrrole, pyridine, pyrimidine, isothiazole, imidazole, indole, purine, quinoline, thiadizole.

As understood in this technical area, there may be a certain degree of substitution on the radicals defined above. References herein to substituted groups indicate that the specified radical may be substituted at one or more available positions with one or more substituents. Such substituents include, for example, and in a non-limiting sense, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, cycloalkyl, aryl, heterocycle, halogen, CN, NO2, CF3, -N (Ra) (Rb ), -ORc, -SRd, -C (O) Re, -C (O) ORf, -C (O) N (Rg) (Rh), -OC (O) Ri; wherein Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh, and Ri are independently selected from hydrogen, alkyl, C1-C6, aryl, heterocycle, and trifluoromethyl.

The term "pharmaceutically acceptable" preferably refers to compositions and molecular entities that are physiologically tolerable and do not normally produce an allergic reaction or similar unfavorable reaction, such as gastric disturbances, dizziness, and the like, when administered to a patient. be human or animal. The term "pharmaceutically acceptable" means that it is approved by a regulatory agency such as the European drug agency or the US regulatory agency, or that it is listed in the United States Pharmacopoeia or other generally recognized pharmacopoeia for use in animals and, accordingly more particularly, in humans.

The term "salts" as used herein refers to any salt of the compound of formula (I) which, when administered to a subject, is capable of providing (directly or indirectly) said compound of formula (I). The term "subject" includes any animal, eg, a mammal, including humans. The preparation of said salts can be carried out by conventional methods known to those skilled in the art.

The term "prodrug" is used, in this description, in the broadest sense, and includes any compound derived from a compound of formula (I) which, when administered to a subject, is capable of providing, directly or indirectly, a compound of formula (I), or a pharmaceutically acceptable salt thereof, in said subject. Advantageously, said derivative is a compound that increases the bioavailability of the compound of formula (I) when administered to a subject (for example, by making a compound of formula (I) administered orally more easily absorbed by the blood), or what enhances the release of a compound of formula (I) in a biological compartment (eg brain or lymphatic system) relative to the parent compound (underivatized). The nature of said derivative is not critical, as long as it can be administered to a subject and provides a compound of formula (I) in a biological compartment of said subject. Such derivatives will be apparent to those skilled in the art, and include, depending on the functional groups present in the molecule and without limitation, the following derivatives of the present compounds: esters, amino acid esters, phosphate esters, sulfonate esters of salts metals, carbamates and amides.

The term "solvate" as used herein includes any compound formed by combining molecules of a solvent with molecules or ions of a compound of formula (I) or a salt thereof; said solvent can be an organic solvent, for example an alcohol, or an aqueous solvent, for example water, in which case the solvate is called a "hydrate".

The term "pharmaceutically acceptable excipient" means one or more solids, or compatible liquids, diluents or encapsulating substances that are capable of being administered to a subject.

The first aspect of the present invention refers to a compound of formula (I):

where

R is selected from the group consisting of:

- hydrogen

- Alkyl optionally substituted by one, two, or three halogen atoms selected from fluorine, chlorine and bromine; (C3-C6) cycloalkyl; alkoxy (CrC6); (C3-C6) cycloalkoxy; cyano and nitro; me

- phenyl optionally substituted by one, two or three groups independently selected from fluorine; chlorine; bromine; alkyl optionally substituted by one, two, or three halogen atoms selected from fluorine, chlorine and bromine; (C3-C6) cycloalkyl; (C1-Ce) alkoxy; (C3-C6) cycloalkoxy; cyano and nitro; or two groups may together form a group -O (CH2) oO-, - (CH2) p-, or -CH = CH-CH = CH-; or

- a heteroaryl group optionally substituted by one, two or three groups independently selected from fluorine, chlorine, bromine, alkyl, cycloalkyl (C3-C6), alkoxy (Ci-C6), cycloalkoxy (C3-C6), cyano and nitro;

Ri and R2 are selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, or heteroaryl, optionally substituted by one, two, or three groups independently selected from fluorine, chlorine, bromine, alkyl, alkoxy, (C3-C6) cycloalkyl, cycloalkoxy ( C3-C6), cyano, nitro and carboxylate or both groups can together form a group -O (CH2) qO-, - (CH2V, or -CH = CH-CH = CH-;

X is selected from an oxygen atom or a sulfur atom;

Y is selected from a carbon atom or a nitrogen atom;

Z is selected from a carbon atom or a nitrogen atom;

n is an integer selected from 0, 1,2, 3, 4, 5 or 6;

* 3 '' indicates the presence of a chiral center whose configuration can be R or S; or their stereoisomers, salts, preferably pharmaceutically acceptable salts, prodrugs or solvates.

In a particular embodiment, said salts of the compound of formula (I) are pharmaceutically acceptable salts, that is, salts that can be administered to a subject and provide a compound of formula (I) in a biological compartment of said individual.

In another particular embodiment, said salts of the compound of formula (I) are pharmaceutically unacceptable salts, which may be useful in the preparation of pharmaceutically acceptable salts of the compound of formula (I), or of its prodrugs or solvates.

The compounds of formula (I), or their salts, can be in crystalline form either as free compounds or as solvates, both forms being included within the scope of the present invention.

In a particular embodiment, said solvate is a pharmaceutically acceptable solvate, that is, it can be administered to a subject and provide (directly or indirectly) a compound of formula (I) or a salt thereof.

In another particular embodiment, said solvate is not pharmaceutically acceptable, but can be used in the preparation of pharmaceutically acceptable solvates of the compound of formula (I) or its salts.

The preparation of said solvates can be carried out by conventional methods known to those skilled in the art, by contacting the compound of formula (I) or a salt thereof with the appropriate solvent.

The compounds of the present invention represented by the formula (I) described above can include enantiomers by the presence of chiral centers or geometric isomers, depending on the presence of multiple bonds (eg R, S). Geometric isomers and enantiomers of the compounds of formula (I) and mixtures thereof are within the scope of the present invention.

In another particular embodiment, the compounds subject to this invention give pharmaceutically acceptable compositions comprising the compounds of formula (I) with a pharmaceutically acceptable carrier, for example, pharmaceutical composition that includes one or more compounds of formula (I), alone or in combination with one or more additional therapeutic agents as a mixture with pharmaceutically acceptable excipients.

In a particular preferred embodiment, the invention relates to compounds of formula (I) in which:

- R is a hydrogen atom

- R1 is selected from the group comprising an alkyl optionally substituted by one or two groups independently selected from fluorine, chlorine, and bromine; (C1-C6) alkoxy, nitro and amino; preferably R1 is -OCH3;

- R2 is hydrogen;

- n is an integer selected from 0, 1 and 2, preferably n = 1;

- X is oxygen or sulfur;

* 3 '' is a carbon atom with R or S configuration in any of its possible combinations

or their stereoisomers, salts, preferably pharmaceutically acceptable salts, prodrugs or solvates.

Particularly preferred compounds of formula (I) of the present invention are the following:

• (R) -1 - (2- (5-methoxy-1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea

• (S) -1 - (2- (5-methoxy-1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea

• (R) -1- (2- (5-chloro-1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea

• (S) -1 - (2- (5-chloro-1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea

• (R) - 1- (2- (1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea

• (S) - 1- (2- (1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea

• (R) -1- (2- (5-methoxy-1 R-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea

• (S) -1 - (2- (5-methoxy-1 R-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea

• (R) -1- (2- (5-chloro-1 R-indole-3-yl) ethyl) -3- (quinuclidin-3-yl) urea

• (S) -1- (2- (5-chloro-1 H-indole-3-yl) ethyl) -3- (quinuclidin-3-yl) urea

• (R) -1- (2- (1 R-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea

• (S) -1- (2- (1 R-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea

The compounds of formula (I) of the present invention can be obtained by a process that involves reacting 3-aminoquinuclidine (II) (Kume et al., Neurosci Lett, 443: 199-203) with R or S configuration.

with the corresponding derivative of 3- (2-isothiocyanatoethyl) -5-R-1 H-indole (III) or N- (2- (5-R-1 H-indol-3-yl) ethyl) -1 H- imidazole-1-carboxamide (IV):

(III) (IV)

where R, R1, R2, X, Y, Z and n have the meaning already indicated.

Therefore, in another aspect, the present invention describes a process for obtaining a compound of formula (I) which comprises reacting said compound of formula (II) with a compound of formula (III) or formula (IV).

Said reaction is carried out in an appropriate inert solvent, at the appropriate temperature. In a particular embodiment, the reaction is carried out initially by mixing the corresponding quinuclidine and the derivative of compound (III) or (IV) at 0 ° C, keeping them with stirring in the presence of an organic base such as diisopropyl ethyl amine ( DIPEA) and in an inert solvent, such as that constituted by a non-protic polar such as, for example, dimethylformamide, dimethylsulfoxide, etc., or their mixtures, dimethylformamide being especially useful.

The compounds of formula (II), (III) and (IV) are known compounds and can be obtained commercially or can be prepared by conventional methods.

The compounds of formula (I) obtained by the above procedure, if desired, can be purified by conventional methods, such as crystallization or chromatography.

The compounds of formula (I) of the present invention exhibit nicotinic receptor modulating activity and free radical scavenging activity.

In a particular embodiment, the invention comprises a compound of formula (I) for use in the treatment of diseases that improve with the administration of a free radical scavenger agent and / or a neuroprotective agent and / or a modulator of nicotinic receptors.

Thus, in other aspects, the invention includes a compound of formula (I) for use in the prevention or treatment of a central and / or peripheral neurodegenerative disease.

Therefore, the invention comprises a compound of formula (I) for use in the treatment of neurodegenerative diseases, eg, AD, PD, ALS, HD, MS.

For administration to a subject in need of treatment, the compounds of formula (I) of the present invention are conveniently formulated with excipients suitable for administration by any appropriate route, for example, orally, parenteral, subcutaneous, intramuscular, intravascular or rectal, preferably being orally.

In a particular embodiment, the pharmaceutical composition of the invention is presented in a pharmaceutical form for oral administration, either in solid or liquid form. The pharmaceutical composition of the invention can also be adapted for parenteral administration (eg, intramuscular, intravenous, etc.). The pharmaceutical composition of the invention can also be adapted for subcutaneous administration in the form of, for example, solutions or sterile suspensions, in the appropriate dosage form; The formulations can be prepared according to conventional methods such as those described in the Spanish, European or United States of America pharmacopoeias.

The compound of formula (I) of the invention will be administered in a therapeutically effective amount that will generally depend on the efficacy of the compound of formula (I) chosen, on the severity of the pathology to be treated, etc. However, it will typically be administered at daily doses between 0.1 and 500 mg of compound of formula (I) per kg of body weight, more preferably the daily doses will be between 25 and 250 mg / kg body weight.

The administration of the compounds of formula (I) of the invention, their salts, prodrugs or solvates, pharmaceutically acceptable, can be carried out alone or in combination with additional drugs, such as drugs useful for the treatment of a neurodegenerative disease, to provide a combination therapy; said additional drugs may form part of the same pharmaceutical composition of the invention comprising the compound of formula (I) and / or its pharmaceutically acceptable salts, prodrugs or solvates, or not, in which case, they will be administered simultaneously or sequentially to the administration of the pharmaceutical composition of the invention. Illustrative, non-limiting examples of such additional drugs that can be used to provide combination therapy include agents such as memantine, vitamins, anti-inflammatories, or antidepressants.

MODE OF EMBODIMENT OF THE INVENTION

The present invention is further illustrated by the following examples, which are not intended to be limiting of its scope.

1. OBTAINING THE COMPOUNDS OF THE INVENTION

The compounds whose biological activity is the object of the present invention were synthesized following the following procedures in organic synthesis.

General procedure for the synthesis of 1- (2- (1fl-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea / urea derivatives

To a suspension of the corresponding 3- (2-isothiocyanatoethyl) -1H-indole or N- (2- (1 H-indol-3-yl) ethyl) -1 H-imidazole-1-carboxamide derivative (1 eq) and DIPEA (3.5 eq) in DMF (10 mL / mmol) at 0 ° C, (R) - or (S) -3-aminoquinuclidine (1.5 eq) was added. The reaction was kept under stirring increasing its temperature to room temperature until the reaction was complete. Then, the solvent was evaporated and the reaction crude was purified by column chromatography to obtain the corresponding derivative.

Example 1: (fí) -1- (2- (5-methoxy-1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea (Compound 1 ).

Following the general procedure described, (R) -3-aminoquinuclidine (90 mg, 0.44 mmol), DIPEA (0.15 mL, 0.88 mmol) and 3- (2-isothiocyanatoethyl) -5-methoxy-1 H-indole (0.100 mg, 0.44 mmol) in DMF (4.4 mL), for 24 h, produced after flash chromatography (CH2Cl2 / MeOH / NH4OH, 96: 3: 1-90: 9: 1), compound 1 (98 mg, 62%). Rf 0.06 (CH2Ch / MeOH 90:10). mp 125-127 ° C. 1H NMR (300 MHz, MeOD) 57.22 (dd, J = 9.0, 5.6 Hz, 1H, H7 '), 7.18 (d, J = 3.2 Hz, 1H, H4'), 7.06 (d, J = 5.1 Hz, 1H, H2 '), 6.75 (dd, J = 9.0, 3.2 Hz, 1H, H6'), 4.37 - 4.15 (m, 1H, H3 "), 3.84 (s, 3H, OCHs), 3.83-3.79 (m, 2H, 2xH1), 2.99 (t, J = 6.6 Hz, 2H, 2xH2) , 2.85 (q, J = 10.9, 8.7 Hz, 4H, 2xH6 ", H7", H8 "), 2.54 (d, J = 10.7 Hz, 1H, H2 ''a), 1.96 (s, 1H, H4 "), 1.80-1.63 (m, 4H, H2" b, H5 "a, H7", H8 "), 1, 52 (dd, J = 15.5, 8.6 Hz, 1H, H5''b) ppm. 13C NMR (76 MHz, MeOD) 5183.6, 155.0, 133.4, 129.3, 124.4, 113.0, 112.9, 112.6, 101.7, 56.4, 55, 8, 51.3, 47.7, 47.2, 46.1,26.5, 26.2, 25.6, 20.3 ppm. HRMS (ES +): Theoretical mass calculated for C19H26N4OS, 358.1827; found [(M) +], 358.1823. IR (film) u / cm-13237, 3053, 2926, 2869, 2321, 1993, 1656, 1616, 1539, 1482, 1452, 1438, 1379, 1341, 1309, 1213, 1167, 1025, 920, 792. [a ] D4 = 13.60 ° ( c. 1.25 mg / mL, MeOH) ee 97%. The enantiomers were separated by reverse phase chiral analytical OVM HPLC, 20 mM KH 2 PO 4 buffer pH 5.9 / AcCN 95: 5, retention time of the (R) enantiomer: 18.497 (minor), 22.357 (major). The purity was determined 100% by reverse phase HPLC C 18 coupled to mass spectrometer by measuring the total ion current (TIC).

Example 2 : (S) -1- (2- (5-methoxy-1rtLindol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea (Compound 2 ).

Following the general procedure described, (S) -3-aminoquinuclidine (86 mg, 0.42 mmol), DIPEA (0.25 mL, 1.5 mmol) and 3- (2-isothiocyanatoethyl) -5-methoxy-1 H -indole (0.90 mg, 0.42 mmol) in DMF (4.2 mL), for 24 h, produced after flash chromatography (CH 2 C h / MeOH / NH 4 OH, 96: 3: 1-90: 9: 1), compound 2 (127mg, 85%). [a] B4 = - 12.12 or (c. 1.32 mg / mL, MeOH) ee 94%. The enantiomers were separated by reversed phase chiral analytical OVM HPLC, 20 mM KH 2 PO 4 buffer pH 5.9 / AcCN 95: 5, retention time of the (S) enantiomer: 18.593 (higher), 24.977 (lower). The purity was determined to be 99% by C 18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

Example 3: (fí) -1- (2- (5-chloro-1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea (Compound 3).

Following the general procedure described, (R) -3-aminoquinuclidine (57 mg, 0.45 mmol), DIPEA (0.18 mL, 1.03 mmol) and 3- (2-isothiocyanatoethyl) -5-chloro-1 H -indole (70 mg, 0.30 mmol) in DMF (3 mL), for 41 h, produced after flash chromatography (CH2Ch / MeOH / NH4OH, 99: 0: 1 -90: 9: 1), compound 3 ( 84 mg, 78%). Rf 0.03 (CH2Ch / MeOH 90: 5). mp 122-124 ° C. 1 HOUR NMR (250 MHz, MeOD) 57.57 (dd, J = 2.1, 0.6 Hz, 1H, H4 '), 7.27 (dd, J = 8.6, 0.4 Hz, 1H, H7 '), 7.13 (s, 1H, H2'), 7.02 (dd, J = 8.6, 2.0 Hz, 1H, H6 '), 4.48-4.29 (m, 1H , H3 "), 3.75 (t, J = 6.8 Hz, 2H, 2xH1), 3.50 (dd, J = 13.5, 9.6 Hz, 1H, H2''a), 2 , 98 (t, J = 6.8 Hz, 6H, 2xH2, 2xH6 ", H7", H8 "), 2.73 (d, J = 13.9 Hz, 1H, H2" b), 2.05 (d, J = 3.9 Hz, 1H, H4 "), 1.81 (dd, J = 8.5, 5.5 Hz, 3H, H5" a, H7 ", H8 ''), 1.61 (dd, J = 12.0, 6.8 Hz, 1H, H5''b) ppm. 13C NMR (63 MHz, MeOD) 5183.9, 160.0, 136.5, 130.2, 125.4, 122.4, 119.1, 113.5, 113.4, 55.7, 50, 6, 47.6, 47.1, 46.3, 26.3, 25.7, 24.7, 19.7 ppm. Theoretical mass calculated for C18H23ClN4S, 362.1332; found [(M + H) +], 363.1407. IR (film) u / cm-13246, 2922, 2867, 2110, 1736, 1652, 1557, 1544, 1479, 1454, 1031, 862, 792. [a] D 4 = 4.59 or (c.1.09 mg / mL, MeOH). The purity was determined to be 97% by C18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

Example 4: (S) -1- (2- (5-chloro-1 H-indole-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea (Compound 4).

Following the general procedure described, (H) -3-aminoquinuclidine (57 mg, 0.45 mmol), DIPEA (0.18 mL, 1.03 mmol) and 3- (2-isothiocyanatoethyl) -5-chloro-1 H -indole (70 mg, 0.30 mmol) in DMF (3 mL), for 64 h, produced after flash chromatography (CH2Ch / MeOH / NH4OH, 99: 0: 1 -90: 9: 1), compound 4 ( 68 mg, 63%). [a] D4 = - 4.67 or (c.1.07 mg / mL, MeOH). The purity was determined 100% by C18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

Example 5: (fí) -1- (2- (1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea (Compound 5).

Following the general procedure described, (H) -3-aminoquinuclidine (30 mg, 0.24 mmol), DIPEA (0.15 mL, 0.84 mmol) and 3- (2-isothiocyanatoethyl) -1 H-indole (49 mg, 0.24 mmol) in DMF (1 mL), for 62 h, produced after flash chromatography (CH 2 Cl 2 / MeOH / Et 3 N, 98: 1: 1-90: 9: 1), compound 5 (25 mg, 32%). Rf: 0.06 (CH 2 Ch / MeOH 90:10). Mp 131-133 ° C. 1H NMR (250 MHz, MeOD) 57.58 (dd, J = 7.6, 1.3 Hz, 1H, H4 '), 7.30 (dt, J = 8.0, 1.0 Hz, 1H , H7 '), 7.06 (dd, J = 8 , 6 , 6.4 Hz, 2H, H2', H 6 '), 6.97 (ddd, J = 8.0, 7.0, 1, 2 Hz, 1H, H5 '), 4.30 (dd, J = 8.0, 4.8 Hz, 1H, H3''), 3.76 (t, J = 7.8, 4.9 Hz, 2H, 2xH1), 3.47-3.35 (m, 1H, H2''b), 3.00 (t, J = 6.9 Hz, 2H, 2xH2), 2.87 (t, J = 7 , 9, 7.5 Hz, 4H, 2xH6 ", H7", H 8 "), 2.59 (dd, J = 13.8, 7.5 Hz, 1H, H2" a), 1 , 98 (s, 1H, H4 "), 1.75 (q, J = 10.2, 7.0, 5.6 Hz, 3H, H5" to, H7 ", H 8 "), 1 .56 (t, J = 15.3, 8.2 Hz, 1H, H5''b) ppm 13 C NMR (63 MHz, MeOD) 5183.4, 138.2, 128.9, 123.7, 122 , 4, 119.7, 119.5, 113.2, 112.3, 55.6, 51.0, 47.7, 47.1, 46.2, 26.4, 26.1, 25.2 , 20.0 ppm. Theoretical mass calculated for C 18 H 24 N 4 S, 328.1722; found [(M + H) + ], 329.1804. IR (film) u / cm -1 3232, 3053, 2923, 2866, 2320, 1538, 1454, 1227, 1093, 1050, 985, 741. [a] D4 = 6.67 ° (c. 1.20 mg / ml, MeOH) ee 99%. The enantiomers were separated by reversed phase chiral analytical OVM HPLC, 5 mM KH 2 PO 4 buffer pH 5.1 / MeOH 90:10, retention time of the (R) enantiomer: 7.583 min. The purity was determined 100% by C18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

Example 6 : (S) -1- (2- (1rtLindol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea (Compound 6 ).

Following the general procedure described, (S) -3-aminoquinuclidine (62 mg, 0.49 mmol), DIPEA (0.31 mL, 1.71 mmol) and 3- (2-isothiocyanatoethyl) -1 H-indole (100 mg, 0.49 mmol) in DMF (2 mL), for 64 h, produced after flash chromatography (CH 2 Ch / MeOH / Et 3 N, 98: 1: 1-90: 9: 1), compound 6 (75 mg, 47%). [a] D4 = - 6.67 ° (c. 1.20 mg / ml, MeOH). The purity was determined to be 98% by C 18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

Example 7: (fí) -1- (2- (5-methoxy-1rtLindol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea (Compound 7).

Following the general procedure described, (fi) -3-aminoquinuclidine (30 mg, 0.24 mmol), DIPEA (0.15 mL, 0.84 mmol) and N- (2- (5-methoxy-1 H-indole) -3-yl) ethyl) -1 H-imidazole-1-carboxamide (65 mg, 0.24 mmol) in DMF (1 mL), for 16 h, produced after flash chromatography (CH 2 Cl 2 / MeOH / Et 3 N, 95: 5: 1-80: 19: 1), compound 7 (25mg, 30%). Rf 0.03 (CH 2 Ch / MeOH 90:10). Mp 117-119 ° C. 1H NMR (250 MHz, MeOD) 57.19 (d, J = 8.7 Hz, 1H, H7 '), 7.02 (d, J = 2.6 Hz, 2H, H2', H4 '), 6 , 73 (dd, J = 8.8 , 2.5 Hz, 1H, H 6 '), 3.90-3.81 (m, 1H, H3 "), 3.80 (s, 3H, OCHs) , 3.41 (t, J = 6.6 Hz, 3H, H2 "b, 2xH1), 2.87 (q, J = 7.0 Hz, 2H, H7", H 8 "), 3 .05-292 (m, 2H, 2xH6 "), 2.88 (q, J = 7.0 Hz, 2H, 2xH2), 2.53 (dd, J = 13.8, 5.0 Hz , 1H, H2''a), 1.89 (q, J = 3.0 Hz, 2H, H4 '', H5''a), 1.82 (dd, J = 11.6, 3.8 Hz , 2H, H7 ", H 8 "), 1.61 (m, 1H, H5 "b) ppm.

13C NMR (63 MHz, MeOD) 5 160.8, 155.0, 133.5, 129.2, 124.4, 113.2, 112.9, 112.5, 101.5, 56.3, 56 , 0.47.7, 47.3, 47.1, 41.8, 27.1, 26.9, 25.1, 19.7 ppm. Theoretical mass calculated for C 19 H 26 N 4 OS, 342.2056; found [(M + H) +], 343.2147. IR (film) u / cm -1 3247, 2929, 2875, 1648, 1556, 1483, 1440, 1213, 1172, 1027, 920, 795. [a] 2D5 = + 4.90 or (c. 1.02 mg / mL, MeOH). The purity was determined to be 97% by C 18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

Example 8 : (S) -1- (2- (5-methoxy-1rt-indole-3-yl) ethyl) -3- (quinuclidin-3-yl) urea (Compound 8 ).

Following the general procedure described, (S) -3-aminoquinuclidine (28 mg, 0.22 mmol), DIPEA (0.14 mL, 0.80 mmol) and N- (2- (5-methoxy-1 H-indole) -3-yl) ethyl) -1 H-imidazole-1-carboxamide (60 mg, 0.20 mmol) in DMF (0.8 mL), for 16 h, produced after flash chromatography (C ^ Ch / MeOH / EtsN , 95: 5: 1-80: 19: 1), compound 8 (45mg, 66 %). [a] D4 = - 19.0o ( c. 1.00 mg / mL, MeOH). Purity was determined 100% by Cia reverse phase HPLC coupled to mass spectrometer measuring total ionic current (TIC).

Example 9: (fí) -1- (2- (5-chloro-1rtLindol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea (Compound 9).

Following the general procedure described, (R) -3-aminoquinuclidine (40 mg, 0.31 mmol), DIPEA (0.2 mL, 0.84 mmol) and N- (2- (5-chloro-1 H-indole) -3-yl) ethyl) -1 H-imidazole-1-carboxamide (80 mg, 0.28 mmol) in DMF (1.1 mL), for 5 days, produced after flash chromatography (CH2Cl2 / MeOH / Et3N, 95 : 4: 1-80: 19: 1), compound 9 (30mg, 31%). Rf 0.03 (CH2Cl2 / MeOH / Et3N, 95: 5: 1-80: 19: 1). Mp 139-141 ° C. 1H NMR (250 MHz, MeOD) 57.50 (dd, J = 2.1,0.6 Hz, 1H, H4 '), 7.26 (dd, J = 8.6, 0.6 Hz, 1H, H7 '), 7.09 (s, 1H, H2'), 7.00 (dd, J = 8.6, 2.1 Hz, 1H, H6 '), 3.79 (dd, J = 8.3 , 4.4 Hz, 1H, H3 "), 3.37 (t, J = 6.8 Hz, 2H, 2xH1), 3.34 (dt, J = 3.3, 1.6 Hz, 2H, H2 "b, H7"), 3.01 - 2.79 (m, 6H, 2xH2, H4 ", H6" a, H7 ", H8"), 2.60 -2.45 ( dd, J = 14.0, 1.8, 1H, H2 "a), 1.85 (d, J = 3.1 Hz, 1H, H6" b), 1.75 (dd, J = 13 , 2.6.9 Hz, 2H, H5 "a, H8"), 1.62-1.44 (m, 1H, H5 "b) ppm. 13C NMR (63 MHz, MeOD) 5 160.7, 136.5, 130.2, 125.3, 122.4, 118.9, 113.5, 113.4, 56.1, 47.8, 47 , 4, 47.1,42.0, 27.0, 26.9, 25.3 ppm. Theoretical mass calculated for C18H23ClN4O, 346.1560; found [(M + H) +], 347.1645. IR (film) u / cm-13250, 2930, 2871, 1638, 1556, 1454, 1314, 1251, 1227, 1098, 1052, 891, 793. [a] 2Ds = + 13.86 or (c. 1.01 mg / mL, MeOH). The purity was determined 100% by C18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

Example 10: (S) -1- (2- (5-chloro-1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea (Compound 10).

Following the general procedure described, (S) -3-aminoquinuclidine (32 mg, 0.25 mmol), DIPEA (0.12 mL, 0.68 mmol) and N- (2- (5-chloro-1 H-indole) -3-yl) ethyl) -1 H-imidazole-1-carboxamide (50 mg, 0.17 mmol) in DMF (0.7 mL), for 14 h, produced after flash chromatography (ChhCh / MeOH / EtsN, 95: 5: 1-80: 19: 1), compound 10 (40mg, 68%). [a] 2D5 = - 12.750 ( c. 1.02 mg / mL, MeOH). The purity was determined to be 96% by means of C18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

Example 11: (fi) -1- (2- (1rtLindol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea (Compound 11).

Following the general procedure described, (fi) -3-aminoquinuclidine (55 mg, 0.26 mmol), DIPEA (0.13 mL, 0.84 mmol) and N- (2- (1 H-indol-3-yl ) ethyl) -1 H-imidazole-1-carboxamide (34 mg, 0.18 mmol) in DMF (1.1 mL), for 24 h, produced after flash chromatography (CH2Cl2 / MeOH / Et3N, 95: 5: 1 -90: 9: 1), compound 11 (50mg, 62%). Rf 0.03 (90:10 CH2Ch / MeOH). Mp 161-163 ° C. 1H NMR (250 MHz, MeOD) 57.55 (dd, J = 8.2, 1.3 Hz, 1H, H4 '), 7.30 (dt, J = 8.2, 2.8 Hz, 1H, H7 '), 7.04 (m, 2H, H2', H6 '), 6.97 (tdd, J = 7.4, 2.3, 1.0 Hz, 1H, H5'), 4.06 - 3.91 (m, 1H, H3 "), 3.79-3.63 (m, 1H, H2" b), 3.49-3.28 (m, 4H, 2xH1, H6 "b, H7 "), 3.01 (d, J = 9.3 Hz, 1H, H4"), 2.95-2.82 (m, 4H, 2xH2, H6 "a, H8"), 2 .75 (t, J = 7.7 Hz, 1H, H5''a), 2.37 (dd, J = 13.5, 5.4 Hz, 1H, H2''a), 2.14-1 , 96 (m, 2H, H7 ", H8"), 1.67 (m, 1H, H5 "b) ppm. 13C NMR (63 MHz, MeOD) 5 159.5, 137.2, 127, 9, 122.6, 121.3, 118.6, 118.4, 112.3, 111.3, 55.4, 46.9, 46.2, 45.9, 40.9, 26.3, 26.1, 23.0, 19.5 ppm. Theoretical mass calculated for C18H24N4O, 312.1950; found [(M + H) +], 313.2017; found [(M + H + CHs) +], 327.2171. IR (film) u / cm-13235, 2941, 2311, 1738, 1624, 1544, 1484, 1452, 1439, 1378, 1351, 1213, 1172, 1064, 1022, 923, 797. [a] D5 = 7.84 or (c. 1.02 mg / mL, MeOH). Purity was determined to be 99% by C18 reverse phase HPLC coupled to mass spectrometer measuring total ionic current (TIC).

Example 12: (S) -1- (2- (1rt-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea (Compound 12).

Following the general procedure described, (S) -3-aminoquinuclidine (55 mg, 0.26 mmol), DIPEA (0.18 mL, 1.04 mmol) and N- (2- (1H-indol-3-yl) ethyl) -1H-imidazole-1-carboxamide (44 mg, 0.26 mmol) in DMF (1.1 mL), for 24 h, produced after flash chromatography (ChhCh / MeOH / EtsN, 95: 5: 1-90: 9: 1), compound 12 (20 mg, 25 %). [a] 2Ds = - 12.75o (c. 1.02 mg / mL, MeOH). The purity was determined to be 96% by means of C18 reverse phase HPLC coupled to a mass spectrometer measuring the total ionic current (TIC).

2. BIOLOGICAL ACTIVITIES STUDIED IN THE COMPOUNDS OF THE INVENTION.

Example 13

Study of the modulating capacity of nicotinic receptors by the compounds object of the invention measured as the variation of the intracytosolic calcium concentration ([Ca2 + 1c induced by the stimulation of acetylcholine.

SH-SY5Y neuroblastoma cell culture

SH-SY5Y [ECACC 94030304] cells, from passages between 5 and 16 after thawing, were kept in Dulbecco's modified Eagle medium (DMEM) containing 15 non-essential amino acids and supplemented with 10% fetal bovine serum. 1 mM glutamine, 50 units / mL of penicillin and 50 pg / mL of streptomycin (reagents from GIBCO, Madrid, Spain). The cells were seeded in containers containing supplemented medium and kept in an incubator at 37 ° C in a humid atmosphere with 5% CO2, passing 1: 4 once a week. For the experiments, cells were grown in 48-well plates at a density of 2x105 cells / well, or in 96-well plates at a density of 8x104 cells / well.

Measurement of the cellular response to the stimulation of nicotinic receptors with acetylcholine.

SH-SY5Y neuroblastoma cells were grown to confluence in 96-well black plates. The cells were loaded with the fluorescent probe fluo-4 / AM at the concentration of 5 pM for 1 hr at 37 ° C in DMEM, adding half the volume of 20% pluronic acid in DMSO. They were then washed twice with a Krebs-HEPES solution and kept at room temperature for 30 min before starting the experiment.

Fluorescence was measured in a fluorescence plate reader (FLUOstar Optima, BMG, Germany), the excitation and emission wavelengths being 485 and 520 nm, respectively. Table 1 lists the effect of the different compounds of the invention on the 10 pM concentration on the increase in the cytosolic calcium concentration ([Ca2 +] c) induced by the stimulation of nicotinic receptors with acetylcholine at the concentration of 100 pM in SH-SY5Y cells as a percentage of inhibition with respect to a control without treatment. A reduction in the relative response indicates the action of the compounds object of the patent on the receptors stimulated by acetylcholine, that is to say, all the subtypes of nicotinic receptors present in these cells.

In order to know its selectivity over the a7 subtype nicotinic receptor, the compound PNU282989 (selective agonist of the a7 receptor) was used in combination with the compound PNU120596 (selective positive allosteric modulator of the a7 receptor), both at a concentration of 10 pM. Stimulation with this combination of compounds produces a selective activation of the a7 nicotinic receptor, therefore, a blockage of the signal of the compounds object of the present invention would indicate activity on this specific receptor subtype. The results are shown in Table 1.

Table 1

Response percentages relative to the acetylcholine agonist or the combination of PNU282989 / PNU120596.

Data are shown as mean ± SEM of duplicates in four different experiments. Student's t test regarding the agonist response * p <0.05; ** p <0.01; *** p <0.001.

The results indicate that the compounds object of the invention are capable of blocking the response of nicotinic receptors induced by their natural agonist, acetylcholine, between 20 and 50%. Furthermore, the compounds object of the invention inhibited the selective stimulation of nicotinic receptors of the a7 subtype. This result shows that the compounds object of the invention act selectively on this receptor subtype. The modulation of the nicotinic signal is related to neuroprotective effects and compared to the control compound, mecamylamine, all of them showed better blocking capacity. Furthermore, this blockade was similar to that of the selective a7 nicotinic receptor antagonist, methylcaconitine (MLA).

Measurement of the cellular response to the stimulation of nicotinic receptors with the compounds object of the invention.

Blocking the response of nicotinic agonists (ACh and the combination of PNU282989 and PNU120596) indicates that the compounds object of the present invention selectively modulate the a7 nicotinic receptor. In order to demonstrate its agonist capacity, SH-SY5Y cells, previously loaded with the Fluo-4AM probe under the same previous conditions, were stimulated with each of the compounds at increasing concentrations in the presence of the selective a7 nicotinic receptor modulator, PNU120596 (10 p.m). The responses obtained were normalized with respect to the response of the combination of agonist and a7 modulator (PNU282989, 10 pM and PNU120596, 10 pM), they were plotted against the concentration of each of the compounds, and the resulting curves were adjusted by no fit. linear. Subsequently, the concentration at which 50% of the maximum normalized response was obtained was calculated. The data obtained are represented in Table 2 as 50% effective concentration values (EC50).

Table 2

Selective agonist capacity of nicotinic receptors of the a7 subtype expressed as EC values ^fifty normalizing the response to 100% with respect to PNU282989 ^.

Data are expressed as the mean value ± SEM of three duplicate experiments in SH-SY5Y cells.

All the compounds object of the invention showed agonist capacity of a7 nicotinic receptors with EC50 values in the micromolar range with values between 1.1 and 11.1 pM. This result shows that all the compounds object of the invention are selective agonists of the a7 nicotinic receptor, promoting the entry of the Ca2 + ion to the cytosol.

Example 14

Measurement of oxygen free radical scavenging capacity

To study the oxygen free radical scavenging capacity of the compounds object of the invention, the ORAC-FL test (absorbance capacity of oxygen radicals) developed by Ou et al. (Ou et al., 2001 , J Agrie Food Chem, 49: 4619-26). The compounds were studied at six concentrations (0.03, 0.1, 0.3, 1, 3 and 5 pM). The different solutions of Trolox (1, 2, 4, 6, 8 pM) and the compounds, as well as melatonin as a positive control at the same concentrations as the compounds, were made using the PBS buffer (10 mM, pH 7, 4) at 37 ° C.

Measurements were carried out at 37 ° C. First, a fluorescence measurement was performed using the FluoStar Optima multi-well reader (BMG Labtech) (Ex. 485 nm, Em.

520 nm) to determine the baseline signal. Subsequently, 25 µl of AAPH (12 mM) were added with a multichannel pipet. Fluorescence was measured for 90 min at 37 ° C. From the area under the curve and the concentrations of the compounds, the slopes of the linear regressions were obtained, which are divided by the slope of the Trolox line, thus obtaining the results of each compound as Trolox equivalents (ET). The data are shown in Table 2 as the mean ± SEM of at least three duplicate experiments at six different concentrations.

The free radical scavenging capacity of the compounds object of the invention has improved with respect to the reference compound Trolox, a known antioxidant, in the same magnitude as the positive control melatonin. In this study, compounds 9, 10 and 11 stand out.

Table 3

Oxygen radical scavenging capacity in Trolox equivalents by the compounds of the invention, as well as melatonin as a positive control

Data are shown as mean ± SEM of four duplicate experiments at 5 different concentrations. Student's t test for paired data * p <0.05, * p <0.01, *** p <0.001 with respect to trolox. Student's t test for unpaired data #p <0.05, ## p <0.01, compared to melatonin; $ p <0.05, $$ p <0.01 between enantiomers.

Example 15

Study of the neuroprotective capacity of the compounds object of the invention against hyperphosphorylation of tau and oxidative stress

Measurement of cell viability: 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazole, MTT

The parameter used to measure cell viability was the metabolic reduction of 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazole (MTT) bromide. The number of living cells is proportional to the amount of formazan formed (Mosmann, 1983 , J Immunol Methods, 65: 55-63). To determine cell viability in human neuroblastoma cells, SH-SY5Y, 10 μl / well of MTT (5 mg / mL) are added and, after 2 h, the medium is removed without losing the formazan crystals, which dissolve in 100 ^ L of DMSO. Subsequently, the absorbance of the samples is measured at 570 nm with the FluoStar Optima reader (BMG Labtech). The absorbance values obtained with the toxin alone and with each compound in the presence of the toxin were subtracted from the absorbance value obtained in basal conditions, without treatment. The value obtained from the subtraction of the less toxic basal absorbance values only, was considered 100% of death and the values obtained with the compounds in the presence of toxic were normalized as percentages of said value. To calculate the survival percentage, these values were subtracted from 100.

Neuroprotection against tau hyperphosphorylation induced by okadaic acid (20 nM), pre-incubation and co-incubation protocol:

We study the neuroprotective capacity of the compounds object of this patent in an in vitro model of tau hyperphosphorylation. The neuroprotective effect of the compounds was evaluated in human neuroblastoma cells, against the hyperphosphorylation of tau produced by okadaic acid (OA), a marine toxin that inhibits serine / threonine phosphatases PP1 and PP2A, which prevents the dephosphorylation of tau (Kamat et al., 2014 , Mol Neurobiol, 50: 852-65), performing the following protocol:

In this protocol, the cells were pre-incubated with each of the derivatives studied at the 1 | iM concentration for 24 h. After the pre-incubation period, the medium was removed and was replaced by culture medium with the compounds and okadaic acid, at a concentration of 20 nM. After 18 h, cell viability was evaluated by the MTT reduction method. In all pharmacological tests, a positive control was used for comparative purposes and to evaluate the goodness of the method used. For this, melatonin (1 ^ M) was used, which has shown neuroprotective capacity in various models.

The results obtained for the compounds object of the present invention are shown in Table 4, and are expressed as a percentage of cell survival and as a percentage of neuroprotective activity.

In this protocol, all the compounds object of the invention are capable of showing a neuroprotective effect, thus favoring cell survival, and therefore highlighting 4, 9 and 2 . Therefore, the combination of pharmacological activities of the compounds object of the invention translates into a neuroprotective effect against the toxicity induced by the hyperphosphorylation of the Tau protein.

Table 4

Percentage of neuroprotection produced by the compounds of the invention and melatonin, at a concentration of 1 pM, against the toxicity induced by okadaic acid.

Data are shown as mean ± SEM of four experiments in triplicate. One-way ANOVA, posthoc Newman-Keuls test. ### p <0.001 with respect to baseline conditions; * p <0.05; ** p <0.01, *** p <0.001 compared to AO.

Neuroprotection against oxidative stress induced by the combination of rotenone (30 uM) and oligomycin A (10 uM):

The neuroprotective effect of the compounds was evaluated in human neuroblastoma cells, against oxidative stress produced by rotenone and oligomycin A, blockers of the respiratory chain of the mitochondria.

Table 5

Percentage of neuroprotection produced by the compounds of the invention and melatonin, at a concentration of 1 pM, against the toxicity induced by okadaic acid.

Data are shown as mean ± SEM of four experiments in triplicate. One-way ANOVA, posthoc Newman-Keuls test. ### p <0.001 with respect to baseline conditions; * p <0.05; ** p <0.01, *** p <0.001 compared to R / O.

In this study, a 24 h pre-incubation was performed with the synthesized compounds at a concentration of 1 pM and a 24 h co-incubation of these in the presence of rotenone / oligomycin A (30 pM / 10 pM, respectively). After 24 hours, cell viability was evaluated by the MTT reduction method.

With this protocol, information is obtained on all the potential biological activities present in the structure under study.

In this model, by being present during the 24 hours prior to the incubation of the toxin, the compound is able to show its activating capacity of a7 nicotinic receptors, which trigger a signaling cascade thus favoring cell survival. In addition, the rotenone / oligomycin A mixture is also present while the cells are exposed to the toxic stimulus, which causes the appearance of a large amount of free radicals inside the cell. These radicals damage the cell and induce cell apoptosis. The survival and protection percentages are summarized in Table 5.

The compounds object of the present invention showed neuroprotective character against the toxicity induced by oxidative stress. The antioxidant character demonstrated by the compounds translates into an increase in cell survival after an insult that causes the appearance of free radicals, compounds 7, 8 and 11 stand out.

Claims (13)

1. A compound of formula (I):

where R is selected from the group consisting of: - hydrogen - Alkyl optionally substituted by one, two, or three halogen atoms selected from fluorine, chlorine and bromine; (C3-C6) cycloalkyl; (Ci-C6) alkoxy; cycloalkoxy (C3-C6); cyano and nitro; me - phenyl optionally substituted by one, two or three groups independently selected from fluorine; chlorine; bromine; alkyl optionally substituted by one, two, or three halogen atoms selected from fluorine, chlorine and bromine; (C3-C6) cycloalkyl; (C1-C6) alkoxy; cycloalkoxy (C3-C6); cyano and nitro; or two groups may together form a group -O (CH2) orO-, - (CH2V, or -CH = CH-CH = CH-; or - a heteroaryl group optionally substituted by one, two or three groups independently selected from fluorine, chlorine, bromine, alkyl, cycloalkyl (C3-C6), alkoxy (Ci-C6), cycloalkoxy (C3-C6), cyano and nitro; R1 and R2 are selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, or heteroaryl, optionally substituted by one, two, or three groups independently selected from fluorine, chlorine, bromine, alkyl, alkoxy, (C3-C6) cycloalkyl, cycloalkoxy ( C3-C6), cyano, nitro and carboxylate or both groups can together form a group -O (CH2) qO-, - (CH2V, or -CH = CH-CH = CH-; X is selected from an oxygen atom or a sulfur atom; Y is selected from a carbon atom or a nitrogen atom; Z is selected from a carbon atom or a nitrogen atom; n is an integer selected from 0, 1,2, 3, 4, 5 or 6; * 3 "indicates the presence of a chiral center whose configuration can be R or S; or their stereoisomers, salts, preferably pharmaceutically acceptable salts, prodrugs or solvates. 2. A compound according to claim 1 wherein R is a hydrogen atom R1 is selected from the group comprising an alkyl optionally substituted by one or two groups independently selected from fluorine, chlorine, and bromine; (C1-C6) alkoxy, nitro and amino; preferably R1 is -OCH3; R2 is hydrogen; n is an integer selected from 0, 1 and 2, preferably n = 1; X is oxygen or sulfur; * 3 '' is a carbon atom with R or S configuration in any of its possible combinations or their stereoisomers, salts, preferably pharmaceutically acceptable salts, prodrugs or solvates. 3. A compound according to claims 1 or 2 characterized in that it consists of: • R) -1 - (2- (5-methoxy-1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea • (S) -1- (2- (5-methoxy-1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea • (R) -1- (2- (5-chloro-1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea • (S) -1 - (2- (5-chloro-1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea • (R) - 1- (2- (1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea • (S) - 1- (2- (1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) thiourea • (R) -1- (2- (5-methoxy-1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea • (S) -1 - (2- (5-methoxy-1H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea • (R) -1- (2- (5-chloro-1 H-indole-3-yl) ethyl) -3- (quinuclidin-3-yl) urea • (S) -1 - (2- (5-chloro-1 H-indole-3-yl) ethyl) -3- (quinuclidin-3-yl) urea • (R) -1- (2- (1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea • (S) -1- (2- (1 H-indol-3-yl) ethyl) -3- (quinuclidin-3-yl) urea 4. A process for the preparation of a compound of formula (I) according to claim 1 characterized by reacting 3-aminoquinuclidine (II) with R or S configuration.

with the corresponding derivative of 3- (2-isothiocyanatoethyl) -5-R-1H-indole (III) or N- (2- (5-R-1 H- indol-3-yl) ethyl) -1 H-imidazole -1-carboxamide (IV):

(III) (IV) where R, R1, R2, X, Y, Z and n have the meaning already indicated. 5. Process according to claim 4, wherein the reaction between the compound of formula (II) and the determined compound of formula (III) in the presence of an organic amine, in a solvent selected from dimethylformamide, dimethylsulfoxide and their mixtures. 6. Pharmaceutical composition comprising at least one compound of formula (I) according to any of claims 1 to 3 and a suitable excipient. 7. Compound of formula (I) according to any of claims 1 to 3 for use in medicine. 8. Compound of formula (I) according to claim 8 for use in the treatment or prevention of diseases that improve with the administration of a nicotinic receptor agonist and / or a free radical scavenger agent. 9. Compound of formula (I) according to claim 9 for use in the treatment or prevention of neurodegenerative diseases. 10. Compound of formula (I) according to claim 10 for use in the treatment or prevention of a central and / or peripheral neurodegenerative disease. 11. Compound of formula (I) according to claim 10 for use in the treatment or prevention of Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis and multiple sclerosis. 12. Compound of formula (I) according to any of claims 7-10, characterized in that it is administered in daily doses between 0.1 and 500 mg. 13. Compound of formula (I) according to claim 12 characterized in that it is administered in daily doses between 25 and 250 mg.