WO2006092032A2

WO2006092032A2 - PHARMACEUTICAL COMPOSITIONS CONTAINING 1-METHYL-3,6,7,8-TETRAHYDROPIRAZOLO[3,4-b]PIRROLO[4,3-d]PYRIDINE-6,8-DIONE DERIVATIVES, USE, AND PROCESS FOR PREPARING THEM

Info

Publication number: WO2006092032A2
Application number: PCT/BR2006/000037
Authority: WO
Inventors: Eliezer De Jesus De Lacerda Barreiro; Carlos Alberto Manssour Fraga; Gisele Zapata Sudo; Roberto Takashi Sudo; Ricardo Menegatti
Original assignee: Universidade Federal Do Rio De Janeiro - Ufrj
Priority date: 2005-03-03
Filing date: 2006-03-03
Publication date: 2006-09-08
Also published as: WO2006092032B1; BRPI0500727A; WO2006092032A3

Abstract

The present invention is related to new derivatives of 1-methyl-3,6,7,8- tetrahydropirazolo[3,4-b]pirrolo[4,3-d]piridin-6,8-dione nucleus, preferably heterocyclic derivatives, acting as hypnotics and analgesic in the central nervous system, being useful in the treatment of anxiety and central hyperalgesia, including: anxiety relief, central hyperalgesia relief in mammals, preferably humans. It is also described pharmaceutical compositions containing said compounds and preparation processes.

Description

Descriptive Report

PHARMACEUTICAL COMPOSITIONS CONTAINING 1-METHYL-3,6,7,8- TETRAHYDROPIRAZOLO[3,4-b]PIRROLO[4,3-d]PYRIDINE-6,8-DIONE DERIVATIVES, USE, AND PROCESS FOR PREPARING THEM.

Field of the Invention

The present invention is related to 1-methyl-3, 6,7,8- tetrahydropirazolo[3,4-b]pirrolo[4,3-d]pyridine-6,8-dione nucleus derivatives, in special to heterotricyclics derivatives. Even more particularly, the present invention is relates to 7-(4-W-phenyl)-1-methyl-3-phenyl-3, 6,7,8- tetrahydropirazolo[3,4-b]pirrolo[3,4-d]pyridine-6,8-dione derivatives, substituted or not, and their isosters, a method of preparing them, pharmaceutical compositions containing them and their uses as sleep and algesia therapeutic modulator agents, with action in the central nervous system, particularly in the treatment of anxiety and central analgesia.

Background of the Invention

In November of 2002 it was published by the "Pharmaceutical Research and Manufacturers of America-PHRMA" governmental and industry sources, which illustrate the current contingent of 99 new candidate drugs for the treatment of the central nervous system diseases. These new candidates are in clinical trials or waiting for the "Food and Drug Administration-FDA" ("Pharmaceutical Research and Manufacturers of America-PHRMA") approval. It is estimated that about 50 million north-Americans will benefit in case that the new candidate drugs be approved by the FDA, what would lead to the life quality improvement and life expectancy for those attacked by some mental diseases such as Alzheimer, depression, schizophrenia, use of drugs and others. In the last half century the evolution of pharmaceutical knowledge helped to transform the treatment of mental diseases. However, little is known about the physiopathology origins of many such diseases. The antidepressant use illustrates how knowledge has helped thousands of people devastated by this disease to become productive individuals. Schizophrenic patients using antipsychotics also have been reintegrated to the social environment. These advances are still becoming possible, that patients with the Alzheimer's disease can age with a better quality of life, even when distant from health care facilities.

The 99 new drug candidates for the treatment of metal diseases are an alternative able to improve the evolution SNC pathology, reducing the corresponding economic and social impacts: 25 are depression treatment related, that reaches more than 25 million Americans ; 25 are the treatment of the improper drug consumption such as alcohol, tobacco and illicit drugs; 18 are for the treatment of anxiety, which affects 13% of the adults between 18 and 54 years old; 17 are for the treatment of dementia and/or Alzheimer, that affects 50% of the people over 85 years; 12 are for the treatment of schizophrenia, that affects 2,2 million adult Americans each year. Other illnesses amongst the mental diseases include deficiency of attention, hyperactivity, illnesses related to the feeding, premenstrual disorders and sleep disorders.

Even though the huge advances in public health in the last half century raised the life expectancy in a general way, the mental diseases continue to present high economic and social impacts. In the United States, the "National Institute of Mental Health" estimates that 1 in each 5 Americans over 18 years (44,3 million of individuals), is attacked by some detectable mental disorder, in the period of one year. About 4 between 10 people develop to a debilitating form of the illness, for example: higher depression, bipolar disorder, schizophrenia and obsessive-compulsive disorder, where the depression leads the list presenting the highest incidence amongst other mental diseases. The mental diseases represent 15% of the overall socio-economic impact.

In 1996, the treatment of mental disorders, of improper use illicit substances and Alzheimer costed U$ 99 billion to the United States alone. U$ 69 billion were spent only with diseases related to mental disorders, which correspond to 7% of the total health budget spent. The cost of Alzheimer disease treatment and other dementias was about U$ 18 billion, and the cost related to improper use of substances was about U$ 13 billion. Considering the global expenses, per year, for patients with Alzheimer disease, about U$ 100 billion are estimated, which correspond to a cost of U$ 174 thousand per capita. Beyond the direct costs, the indirect costs also presents high onus to the american economy. In 1990, U$ 79 billion were spent with the treatment of mental diseases, 80% of the total (U$ 63 billion) being related to the cost of death, due to loss of productivity in usual activities, resulting from of the disease evolution. Other U$ 12 billions are related to mortality cost, due to loss of productivity because of the premature death. Other U$ 4 billions are related to the loss of productivity, due to the special care required by people diseased people, or due to the attention dedicated to the patient by the care responsible person. Schizophrenia was responsible for 15% of the indirect costs in 1990.

According to the "Office of National Drug Control Policy", the illegal drugs had been responsible for the cost of U$ 143.4 billions in the american economy, in 1998. In addition, U$ 13 billions were spent with health care costs with drug users, beyond the expense of U$ 32.1 billion in the combat to their use.

Anxiety disorders, which includes panic disorder, obsessive-compulsive disorder, post-traumatic "stress" disorder, generalized anxiety disorder and phobias, affect 19 million adults in the age range of 18 to 54 years, or about 13% of people in this age group annually. About 4 million Americans aging between 18 and 54 years, or about 2,8% the people in this age present clutters of annually generalized anxiety. Approximately 2,4 million american adults have panic disorders, which is twice more common in women. About 4 million americans between 18 and 54 years, or about 2,8% of people in this age range present generalized anxiety disorders annually. Approximately 2,4 million american adults have panic disorders, which is about twice more common in women. Panic disorder is frequently complicated by depression disorders and by indiscriminated use of improper substance. Panic disorder occurs together with other specific anxiety disorders, including social phobia (above 30%), generalized anxiety disorders (above 25%), specific phobias (above 20%) and obsessive-compulsive disorder (above 10%). About 5,3 million Americans between 18 and 54 years, or 3,7% of people in this age range suffer of social phobia during the period of one year. It affects men and women in equal ratios. Deficiency of attention and hyperactivity disorder are the most common disorders diagnosed in children, affecting 2 million young people in school age, and a unknown number of people in the adult age and adolescence. About one child in each american classroom requires some assistance related to deficiency of attention and hyperactivity disorder, that occur three times more in boys than in girls. Deficiency of attention and hyperactivity disorder can occur concomitantly with learning difficulties (above 25%), language disorders (above 35%), behavior disorders (above 20%), mood disorders (above 20%) and anxiety disorders (above 25%). Above 60% of children with "tics" disorders also suffers of deficiency of attention and hyperactivity disorder. Alzheimer's disease, which is the more common cause of dementia in people with superior more than 65 years, affects about 4 million Americans. The duration of the disease, since the beginning of the symptoms until death, varies between 8 and 10 years. It is estimated that 360,000 new cases of sick people with Alzheimer will occur each year. The prevalence of Alzheimer's disease doubles in each five years around 65 years old. Projections indicate that, in 2050, 20 million people in the United States with more than 85 years will be in risk of Alzheimer. Approximately three quarters people with Alzheimer try depression, psychoses or agitation.

Beyond Alzheimer's disease, the dementias, in a general way, are usually lived by nurses. About 67,4% of them come across with this pathological picture during their residences. Behavior disturbs, including physical aggression, agitation and sleep problems, affect above 80% of the patients with dementia diseases. Between 12 and 15% of people above 65 years old with medium cognitive deficiency develop Alzheimer's disease each year (or about 40% after three years); however, only 1% of healthy people above of 65 years old develop Alzheimer's disease (or 3% after three years). Mood disorders affect more than 20 million Americans of all races and ethnic groups, in all periods of life, since infancy until old people. Approximately twice more women (12,4 million or 12%) than men (6,4 million or 6.6%) are affected by a depressive disorder in the United States each year. The bigger depressive disorder is the leader cause of socio-economic invalidation in the United States and other parts of the world. It approximately affects 10 million Americans (about 5%) above 18 years, and about 6% of children between 9 and 17 years. Approximately twice more women (6,7 million or 6.5%) than men (3,2 million or 3.3%) suffer of this disorder. For year 2020, the depression is projected to be the second cause of invalidation in the world. Bipolar disorder affects about 2,3 million Americans or 1 ,2% of the american population annually. Men and women are equally affected by this disorder. Approximately a third part of those with bipolar disorder before 18 years old has recurrence during the adult age. Approximately 127 million adults in the United States are overweight, 60 million are obese and 9 million are severely obese. Nowadays 64.5% of Americans above 20 years are overweight and 30.5% are obese. The prevalence of severe obesity is now of 4.7%, above that one of 2,9% reported in the period from 1988 to 1994 by the "National Heath and Nutrition Survey". Approximately 30.3% of children between 6 and 11 years old are overweight, and 15.3% are obese. Among adolescents between 12 and 19 years old, 30.4% are overweight and 15.5% are obese. During infancy, the prevalence of weight excess is higher in boys (32.7%) than in girls (27.8). In the adolescence, the prevalence of weight excess is the same between girls (30.2%) and the boys (30.5%). The prevalence of obesity quadruplicated from 1974 to 2000 between boys and girls. Estimates indicate that annually 300,000 Americans are going to die due to obesity and weight excess. Obesity is the second cause of death prevalence in the United States.

Above 40% of the women who menstruate suffer of some pre-menstrual syndrome symptom. While many symptoms are medium, perhaps above 10% of women present more severe symptoms called pre-menstrual dysphoric disorder, which can intervene significantly in social and work functions.

Schizophrenia affects 2.2 million Americans or about 1.1% of population above 18 years old, without distinction between sexes. The disorders frequently are earlier manifested in men, usually in the end of the adolescence, beginning of 20 years old, while in women they appear generally between 20 or 30 years old. Above 90% of people suffering of schizophrenia are not employed, either in integral regime or in partial one, and the others work in partial regime or int competitive activities, such as in shelters.

Pathophysiology of anxiety

The γ-aminebutiric acid (IT BRAGS) is the main inhibitory neurotransmitter of mammals' SNC, being its action expressed by the modulation of two families of receivers, mainly. GABAA receivers are ionotropic, because they are connected to chloride ion canals, while GABAB receivers are methabotropics, connected to G protein, keeping a narrow relation with potassium (K+) and/or calcium (Ca2+) canals, and with second messengers as ciclase adenylate, located in the pre-synaptic cleft (Cosford, N. D. P.; Mc Donald, I.; Schwiger, And J.; Ann. Rep Med Chem, 1998, 33, 61-70). GABAA receivers have post-synaptic localization, of fast action, with selective permeability for chloride ions. The membrane potential in balance for ions of chloride he is, in general, slightly negative in relation to the potential in the cell rest, and because of that the increase of the permeability to chloride hyperpolarize the cell, thus reducing its excitability (Cosford, N. D. P.; Mc Donald, I. A.; Schwiger, E. J.; Ann. Rep Med Chem, 1998, 33, 61-70).

GABAA receivers are pentameric protein structures, constituted of homologous subunits, arranged around a central canal, with a large extracellular subunit, where is the GABA's binding site. In few cases, functional homopentamerous are formed. There were identified already 16 subunits of GABAA receivers homologous in mammals (α-i-e, β-i-₃, γi-3, δ, ε, π e θ), which can be divided in classs based on the identity degree of their sequences (Cromer, B.A.; Morthon, CJ. ; Parker, M.W.; Trends Biochem. Scien., 2002, 27, 280-287). These distinct subunits confer a peculiar standard, not only in the structure heterogeny, but also in the pharmacologic heterogeny (Cromer, B. A.; Morthon, CJ. ; Parker, M.W.; Trends Biochem. Scien., 2002, 27, 280-287). The majority of the native GABA _A receivers contains subunits α, β e γ.

The subunit composition is what determines the sensitivity of the receivers. The subunits α e β are necessary for the activation function of GABA_A ionic canal, and the subunit γ confers sensitivity to benzediazepinics (1). GABA_A receivers are also sensible to other ligands including barbiturates, alcohols, some steroids, among others. It has to be said that the concomitant use of barbiturates or benzediazepinics with alcohol causes severe depression of the central nervous system (CNS). These substances interact in an allosteric way with GABAA receivers and modulate the gabaergic reply (Cromer, B. A.; Morthon, CJ. ; Parker, M.W.; Trends Biochem. Scien., 2002, 27, 280-287). The anxiolitic pharmacos¹ class (1) was fortuitous discovered in the 50 decade, thanks to Leo H. Stembach works, during his post-doctoral in the Hoffmann-La Roche laboratory (Stembach, L. H.; J. Med. Chem. 1979, 22, 1). Since then, new molecular standards with anxiolitic properties and hypnotic β- carbolines (2), piridodindoles (3), pirazoloquinolines (4-5) imidazo[1 ,2- a]pyridines (6-7), with non benzodiazepinic structure, has being developed, culminating with the construction of pharmacophoric models (Trudell, M. L.; Lifer, S.L; Tan, Y.; Martin, M.J.; Deng, L.; Skolnick, P.; Cook, J. M.; J. Med. Chem. 1990, 33, 2412-2420; Allen, M.S.; Tan, Y.; Trudell, M.L.; Narayanan, K.; Schindler, LR.; Martin, M.J.; Schultz, C; Hagen, T.J.; Koehler, K.F.; Codding, P.W.; Skolnick, P.; Cook, J.M.; J. Med. Chem. 1990, 33, 2343-2357; Martin, M.J.; Trudell, M. L; Arau^' zo, H. D.; Allen, M.S.; LaLoggia, A.J.; Deng, L; Schultz, CA.; Tan, Y.; Bi, Y.; Narayanan, K.; Dorn, LJ. ; Koehler, K.F.; Skolnick, P.; Cook, J.M.; J. Med. Chem. 1992, 35, 4105-4117; Kitaura, Y.; Nakaguchi, O.; Takeno, H.; Okada, S.; Yonishi, S.; Hemmi, K.; Mori, J.; Senoh, H.; Mine, Y.; Hashimoto, M.; J. Med. Chem. 1982, 25, 337-339; Takada, S.; Shindo, H.; Sasatani, T.; Chomei, N.; Matsushita, A.; Eigyo, M.; Kawasaki, K.; Murata, S.; Takahara, Y.; Shintaku, H.; J. Med. Chem. 1988, 31, 1738-1745; Shindo, H.; Takada, S.; Murata, S.; Eigyo, M.; Matsushita, A.; J. Med. Chem. 1989, 32, 1213-1217; Gupta, S.P.; Progress Drug Res. 1995, 45, 67).

The benzodiazepinics class, for example diazepam (1), presents specter of therapeutical application very varied. Beyond its use as anxiolitic and hypnotic, it can also be used as anticonvulsivant, miotonolithic, reducing the skeletic musculature tonus. All the applications cited above are due to the reinforcement effect of the benzodiazepinics to the inhibitory neurons located in brain and marrow (Hardman, J. G.; Limbird, L. E.; Goodman & Oilman's The Pharmacological Basis of Therapeutics. 10^th, New York: McGraw-Hill, 2001 ; Lϋllmann, H.; Mohr, K.; Farmacologia Texto e Atlas. 4^a ed, Portho Alegre: Artmed, 2004). In cases of fear neurosis, phobia and depression by fear, the benzodiazepinics act in palliative way, for they don't cure the psychic disorder, but attenuate its reactions. Because of that, benzodiazepinics are many times indicated to reduce the cardiac stimulation caused by anxiety in heart attack.

Due to the benzodiazepinics class present tropism only for the gabaergic pathway in the central nervous system, not influencing in functions as sanguine pressure, cardiac frequency or body temperature, they present sufficiently safe therapeutical index (>100), being more than ten times higher than barbiturate pharmacos class. However, patients who use benzodiazepinics show less speed action when in contact with external stimulatons, not being recommended to them to do things that demands attention as, for example, to ride. Furthermore, being psychotropics pharmacos, they can cause personality and behavior modifications and under chronic use can develop dependence. The dependence is observed when the treatment is stopped, when there are observed abstinence symptoms, such as untranquillity, anxiety and convulsions (Hardman, J. G.; Limbird, L. E.; Goodman & Oilman's The Pharmacological Basis of Therapeutics. 10^th, New York: McGraw-Hill, 2001 ; Lϋllmann, H.; Mohr, K.; Farmacologia Texto e Atlas. 4^a ed, Portho Alegre: Artmed, 2004). Although some ligands as cited previously by numbers 2-5 are recognized as presenting high affinity for gabaergic-GABA_A receiver (Ki in the nanomolar order), the search for new molecular standards that present functionality and selectivity, it means, that present effectiveness and therapeutical security, without showing the adverse effects previously mentioned, have been stimulated in the last years.

The patent literature about composites with activity on GABA receivers is very rich. We can cite as example the document US 2003/060467, which discloses the pirazolo-triazine use as GABAergic modulators, useful in the treatment and/or prevention of disorders of the central nervous system, including anxiety and convulsions.

Document EP 270 494 describes ligands and modulators of benzodiazepinics receivers, acting in the central nervous system, being that ligands presenting a pirazolo [ 3,4-d]-pyridine-3-one structure. Document WO 99/00391 describes composites derived from pirazolo- piridazinones such as GABA ligands, and which are useful in the treatment and/or prevention of disorders of the central nervous system, including anxiety and convulsions.

Document WO 99/48892 describes composites which are very similar to the one of the present invention, more specifically they are pirazolo-[4,3-c]- pyridine derivatives, that also act as GABA ligands, acting in the central nervous system.

Document WO 01/44244 describes pirazolo-[3,4-b]-pyridines derivatives acting in GABA receivers. However, the general formula of such composites presents an alkoxyl bonded to the piperidinic ring.

Although there are prior art related to the use of pirazolo-pyridines as GABAergic modulators, the structure presented in this work has never described in a patent document. The object of the present invention, although it also belongs to the same class of the composites described in document WO 01/44244, it differs from claimed composites for not presenting an alkoxyl bonded to the pyridinic ring. Brief description of the Drawings

The Figure 1 shows a graph where the effect of the composites L872 and

L873 analyzed in the duration of the induced hypnosis by the pentobarbital are demonstrated. Each point represents the ± EPM average. N=10 mice per dose.

* P<0.05 when compared to the control (treatment with DMSO).

The Figure 2 shows two graphs where correlations between the hypnotic effect and the use of increasing doses of Lassbio 872 and Lassbio 873 are made. N=10 mice per dose. The Figure 3 shows a graph where it is demonstrated the duration of the induced hypnotic effect for Lassbio 872 and Lassbio 873, after i.v. administration in 25 and 50 μg.kg^"1 doses. The number of mice used is presented between parentheses. * P<0.05 when compared to the dose of 25 μg.kg-1. The Figure 4 shows two graphs where the effect of the composites

Lassbio 872 and Lassbio 873 at the reply time to the hot plate test is demonstrated. Different doses of these composites had been managed by the venous way in 10 mice. * P<0.05 when compared to the control (absence of the test-compound).

Summary of the Invention

It is an object of the present invention to provide alternatives to the currently available molecules used as sleep modulating and/or algesia with action in the central nervous system. More specifically, such molecules had been planned from the archetype Zolpidem (6).

The molecules of the present invention are particularly useful in the treatment of anxiety and hyperalgesia. Therefore, an additional object of the present invention is to provide pharmaceutical compositions for the treatment of anxiety and hyperalgesia. Given the advantages of the molecules' selectivity of the present invention, the pharmaceutical compositions of the present invention can be administrated in a larger variety of presentation forms, which results in benefits for the user and larger production flexibility. Therefore, another object of the present invention is to provide options for the limitations of the administration of pharmaceutical compositions for the treatment of anxiety and central analgesia disorders.

The molecules of the present invention have distinct ways of synthesis when compared to the other molecules used currently for anxiety and hyperalgesia treatment. Moreover, the synthetic stages involved in the production of composites of the present invention are simpler and less expensive, resulting in advantages in the industrial point of view. Therefore, an additional object of the present invention is to provide processes for the production of hypnotic and analgesic molecules related here.

Detailed Description of the Invention Despite the brief reference to the objectives of the present invention made, it will be started to describe it in its details, using, always when opportune, the preferential concretions of the invention. It is important to mention that the examples here described do not have to be faced in such way to limit possible accomplishments of the invention. As already mentioned, the present invention intends to provide alternatives to the molecules used as hypnotic and/or analgesic with action in the central nervous system currently available, planned from the archetype Zolpidem (6) and other synthetic derivatives described in literature as ligands of gabaergics receptors, whose formulas are below transcribing:

DIAZEPAM(I) BETA-CARBOLINAS (2) PIRIDODINDOIS (3)

PIRAZOLOQUINOLINA (4) PIRAZOLOQUINOLINA (5) ZOLPIDEM (6)

This invention has, still, as one of its innovative characteristics, the synthesis of new functionalized heterotricyclic derivatives, derived from 1- methyl-3,6,7,8-tetrahydropirazolo[3,4-b]pirrolo[4,3-d]pyridine-6,8-dione system, rationally planned as candidates to archetypes of new anxiolitic agents. These new derivatives present as main structural characteristics the heterotricyclic standard, where the functions pirrolic and β-dicarbonilic consist in the pharmacophoric group involved on the recognition by GABA_A receivers, it means, involved on the primary recognition by the gabaergic receptors; the other aromatic subunits, which act as secondary pharmacophoric group, with biophoric characteristics (electronic and hydrophobic), necessary for the recognition by the receiver-target, through interactions of van der Waals between their aromatic ring and similar sites. The use of this structural standard in hypnotic and analgesic analogous was not mentioned previously, and, therefore, the described compounds described in this invention and their synthetic methodology represent an innovation among the hypno-analgesics agents of central action.

The compounds described in this invention belong to the class of the derivatives of the 1-methyl-3,6,7,8-tetrahydropirazolo[3,4-b]pirroIo[4,3- d]pyridine-6,8-dione nucleus, and their isosters, of general structure (II):

wherein:

R is independently, hydrogen, alkyl, cycloalkyl, phenyl-W, furyl, tiophenyl, pyridinyl, pyrimidinyl, pyrrolyl, thiazolyl, quinazolyl ou isoquinolyl; and

W is, independently, hydrogen, ortho-alkyl, ortho-cyc\oalkyl, ortho- alkoxyl, ortho-cycloalkoxyl, o/ffto-thioxyl, ortΛo-aryoxyl, o/t/70-sulfones, ortho- sulphides, ortøo-sulphoxides, orf/?o-sulfonates, o/ffto-sulfonamides, ortho- amine, ortho-amide, ortøo-halides, σ/ffro-carboalkoxyl, orfΛo-carbothioalkoxyl, o/t/7o-trihaloalkene, ortho-ciano, ortho-nitro, meta-alkyl, meta-cycloalkyl, meta- alkoxyl, meta-cycloalkoxyl, meta-thioxyl, meta-aryoxyl, meta-sulfones, meta- sulphides, meta-sulphoxides, meta-sulfonates, meta-sulfonamides, meta-amine, meta-amide, meta-halides, /nefa-carboalkoxyl, meta-carbothioalkoxyl, meta- trihaloalkene, /nefa-ciano, meta-nitro, para-alkyl, para-cycloalkyl, para-alkoxyl, para-cycloalkoxyl, para-thioxyl, para-aryoxyl, para-sulfones, para-sulphides, para-sulphoxides, para-sulfonates, para-sulfonamides, para-amine, para-amide, para-halides, para-carboalkoxyl, para-carbothioalkoxyl, para-trihaloalkene, para-ciano or para-nitro;

The compounds of formula (II) had been obtained between low and satisfactory chemical yields, using synthetic methodology described herein, which is characterized by presenting few steps, starting from commercially available compounds, what characterizes this synthetic methodology for industrial use.

The compounds of the present invention had been planned through convergent syntheses, by using classic reactions as: - condensation to carbonyl;

- Michael's addition;

- hetero-Diels-Alder;

More specifically, the compounds of formula (II) of the present invention can be prepared by a process that comprises the steps of: - condensation of phenylhydrazine with β-iminobutironitrile, in water and chloridric acid; and hetero Diels-Alder, between 2-heteroazadiene e N- phenylmeleimidines functionalized.

For exemplification, we describe in this report the synthesis of the following compounds:

- 5-amine-1 -phenyl-3-methyl-pirazole; - Λ/,Λ/-dimethyl-3-methyl-1-phenyl-1H-5-pirazoliliminometanamine;

- 1-(4-nitrophenyl)-2,5-dihydro-1H-2,5-pirroledione;

- 1-(4-chlorophenyl)-2,5-dihydro-1/-/-2,5-pirroledione; -1-methyl-7-(4-nitrophenyl)-3-phenyl-3,6,7,8-tetrahydropirazolo[3,4- b]pirrolo[3,4-d]pyridine-6,8-dione (called Lassbio 872 or L872); e

-1-methyl-7-(4-chlorophenyl)-3-phenyl-3,6,7,8-tetrahydropirazolo[3,4- b]pirrolo[3,4-d]pyridine-6,8-dione (called Lassbio 873 or L873);

A detailed description of the synthetic methods of this invention for some of the claimed compounds is described as follows, including important spectroscopic data for their characterization. The next examples illustrate, but do not limit the present invention.

Example 1 Preparation of 5-amine-1-phenyl-3-methyl-pirazole derivative

General Procedure a) On 80 mL of dried benzene was added 0,79 mol of metallic sodium (18g) finely cut, this mixture being kept under magnetic agitation and heating until reflux. After that it was added by hypodermic syringe 180 m L (3,1 mol) of acetonitrile - during the reagent addition it is necessary to take precautions due to the vigorous gaseous unfastening observed - and the system was kept in reflux for 3 hours. The reaction mixture was taken to the ambient temperature and ethanol was added slowly, in order to consume exceeding sodium.

The product was poured in water and extracted with dichloromethane, dry under magnesium sulphate, filtered and evaporated, the solvent supplying a viscous liquid of light yellow color-unstable product at ambient temperature - with 20% of yield. b) On the β-iminobutironitrile formed there were added 36 mL (0,36 mol) of phenylhydrazine and 50ml of a 2:1 solution (v/v) of chloride acid and water. The mixture remained under magnetic agitation and heating at the reflux temperature for 30 minutes. The ending of the reaction was indicated by c.c.f. (mixture 1 :1 v/v of ethyl acetate and petroleum ether as eluant). The reaction mixture, then, was poured on frozen water and the environment was neutralized with NaOH 10% solution, being obtained a orange precipitate at 90% of yield. This, after clearing in ethanol and water until turbidity, supplied PF= 1100C.

RMN - ¹H (300 MHz) CDCI₃ / TMS (δ-ppm): 7,47-7,40 (5H, m, H-2'-6'); 5,38 (1 H, s, H-4); 3,88 (2H, s, NH₂); 2,19 (3H, s, CH₃);

RMN - ¹³C (75 MHz) CDCI₃ / TMS (δ-ppm): 149,2 (C-5); 145,4 (C-3); 138,4 (C-T); 129,2 (C-3¹); 127,0 (C-4¹); 123,7 (C-2¹); 90,6 (C-4); 13,7(CH₃); Example 2

Preparation of N,N-dimethyl-3-methyl-1-phenyl-1H-5-pirazoliminometanamine derivative

In a 25 ml_ balloon was added 0,43 g (2,5 mmol) of 3-methyl-1-phenyl- 1 H-5-pirazolemine, 0,37 mL (2,75 mmol) of dimethylformamide dimethylacetal and reaction mixture kept under temperature of 90⁰C for 5 hours. In the end of the reaction, it was extracted with dichloromethane and solution saturated with ammonium chloride, the organic phase drought with sodium sulphate and concentrated under reduced pressure. There were obtained 0,56 g (98%) of Λ/,/V-dimethyl-3-methyl-1-phenyl-1/-/-5-pirazoliminometanamine, as amorphous crystals of brown color, P.F.=75°C, Rf=0,37 (CH₂CI₂:Me0H-95:5) e Rf=O, 11 (n- hexane:ethyl acetate-7:3).

RMN - ¹H (200 MHz) CDCI₃ / TMS (δ-ppm): 7,16-7,52 (6H, m, C₆H₅ e N=CH); 5,36 (1 H, s, H-4); 3,85 (6H, s, N(CH₃) ₂); 2,20 (3H, s, CH₃); RMN - ¹³C (75 MHz) CDCI₃ / TMS (δ-ppm): 154,0 (N=CH); 149,0 (C-5);

145,2 (C-3); 138,4 (C-1); 129,2 (C-3' e 5¹); 126,6 (C-4¹); 123,4 (C-2¹ e 6'); 90,3 (C-4); 39,8 (NCH₃); 34,1 (NCH₃); 13,6(CH₃).

Example 3 Preparation of 1-methyl-7-(4-clorophenyl)-3-phenyl-3,6J,8- tetrahvdropirazolof3,4-b1pirrolor3,4-dipyridine-6,8-dione (L872) derivative

In a 50 mL balloon was added 0,56 g (2,5 mmol) of Λ/,Λ/-dimethy!-3- methyl-1-phenyl-1 H-5-pirazoliminometanamine, 10 mL of acetic acid, 1,29 g (5 mmol) of 1-(4-chlorophenyl)-2,5-dihydro-1H-pirrole-2,5-dione, keeping under agitation and at the temperature of 50⁰C for 48 hours. In the end of the reaction, the precipitate product was filtered in a Buckner funnel and washed with ethanol. It was obtained 0,19 g (20%) of 7-(4-clorophenyI)-1-methyl-3- phenyl-3,6,7,8-tetrahydropirazolo[3,4-b]pirrolo[3,4-d]pyridine-6,8-dione, as amorphous crystals of yellow color, P.F.=246-248°C, Rf=0,87 (CH₂Cl₂:Me0H- 95:5) e Rf=0,64 (n-hexano:acetato de etila-7:3). RMN - ¹H (500 MHz) CDCI₃ / TMS (δ-ppm): 9,08 (1 H, s, H-C=N); 8,14

(2H, d, J=8,0 Hz, H-orf/70-pirazole); 7,50 (2H, t, J= 8,0 Hz, H-meta-pirazoie);

7,46 (2H, d, J= 8,2 Hz, H-ortΛo-amide); 7,38 (2H, d, J=8,2 Hz, H-meta-amide);

7,32 (1 H₁ t, H= 8,0 Hz, H-para-pirazole); 2,90 (3H₁ s, CH₃); RMN - ¹³C (125 MHz) CDCI₃ / TMS (δ-ppm): 166,7 (C=O); 165,4 (C=O);

153,7 (C-3); 144,0 (C-6); 143,7 (C-4); 138,5 (C-N(C=O)₂); 134,6 (C-5); 134,3

(C-3b); 129,8(C-Cl); 129,5 (C-3 e 5-meta-amide); 129,3 (C-3 e 5-meta-pirazole);

127,7 (C-2 e 6-OA#?o-amide); 127,1 (C-4-para-pirazole); 121 ,9 (C-2 e 6-ortho- pirazole); 110,7 (C-3a); 15,1 (CH₃).

Example 4

Preparation1-methyl-7-(4-nitrophenyl)-3-phenyl-3,6,7,8-tetrahvdropirazolof3,4- b1pirrolor3,4-d1pyridine-6,8-dione (L873) derivative

In a 50 mL flask was added 1 ,12 g (5 mmol) of N,N-dimethyl-3-methyl- 1-phenyl-1H-5-pirazoliminometanamine, 20 mL of acetic acid, 2,68 g (10 mmol) of 1-(4-nitrophenyl)-2,5-diidro-1H-pirrole-2,5-dione, keeping under agitation and at the temperature of 50⁰C for 48 hours. In the end of the reaction, the precipitate product was filtered in a Buckner funnel and washed with ethanol. It was obtained 0,70 g (35%) of 1-methyl-7-(4-nitrophenyl)-3-phenyl-3, 6,7,8- tetrahydropirazolo[3,4-b]pirrolo[3,4-d]pyridine-6,8-dione, as amorphous crystals of yellow color, P.F.=238-240°C, Rf=0,87 (CH₂CI₂:Me0H-95:5) e Rf=0,56 {n- hexano:acetato de etila-7:3).

RMN - ¹H (500 MHz) CDCI₃ / TMS (δ-ppm): 9,12 (1 H, s, H-C=N); 8,36

(2H, d, J=9,0 Hz, H-mefa-amide); 8,15 (2H, d, J= 8,0 Hz₁ H-ortøo-pirazole); 7,74 (2H, d, J= 9,0 Hz, H-onf/?o-amide); 7,51 (2H, t, J=8,0 Hz, H-meta-pirazole); 7,34

(1H, t, H= 8,0 Hz, H-para-pirazole); 2,92 (3H, s, CH₃).

Pharmacologic Evaluation

Possible Activities of new compounds in the central nervous system was evaluated in vivo of through of specific methodology to identify hypnotic and/or analgesic activity. The results obtained have demonstrated important hypnotic and analgesic activity, particularly of L873.

1. Hypnotic Activity

Initially, the experimental model was used in which it determined that influence of compounds L872 and L873 in duration of induced hypnosis for barbituric, sodium pentobarbital. The results displayed in figure 1 to confirm the potential of L872 and L873 in the time of hypnosis provoked for sodium pentobarbital (25mg/kg).

The dose-response curve related to duration of hypnosis and the crescent dose of compounds is presented in figure 1. The compounds LASSBio 872 and LASSBio 873 had increased significantly, of the form dose-dependent, the duration of induced hypnosis for pentobarbital. The maximum effect was reached in dose of 6 mg.Kg-1 to the LASSBio 872, where the time of control hypnosis increased of 41.7 ± 17,7 min to 90.9 ± 5,1 min (n=10, PO.05). In the same dose of 6 mg.Kg-1 , the LASSBio 873 increased the duration of hypnosis to 162.7 ± 25.8 min, about 4 times control time.

As these compounds were capable to extend the effect of hypnosis induced by a barbituric. In the subsequent stage, they were evaluated for a possibility of when administrated separately could provoke hypnosis in mice.

The injection of the compounds in mouse in doses that ranged from 25 to 500 μg.kg^"1 was followed by the appearance or not of loss of posture, i.e, of hypnotic effect. By this method was determined the doses that produce hypnosis in 50% in animals tested (DH5₀).

The figure 2 shows that the DH₅₀ for LASSBio 872 and LASSBio 873 were 105.0 and 42.6 μg.kg^~1, respectively. Due to the fact that the DH50 of LASSBio 873 was smaller than LASSBio 872, LASSBio 873 is the more powerful compound capable of inducing hypnosis in mouse after injection. In this way, LASSBio 873 was the more powerful compound in extend the hypnotic effect of the barbituric and also induction of hypnosis when administrated separately. These results indicate that this compound could be of clinical interest for treatment of the anxiety.

Another important aspect for hypnotic effect was promoted by LASSBio

872 and LASSBio 873 would be the determination of duration of this effect when administered intravenously. The figure 3 shows the duration of hypnosis induced by LASSBio 872 and 873 in doses of 25.50 μg.kg^""1. The hypnosis induced by LASSBio 872 showed duration of 26.1 ± 5.2 e 53.7 ± 9.3 seconds in doses of 25 and 50 μg.kg^"1, respectively, suggesting that the duration of hypnotic effect was dose-dependent. Similar results were observed with LASSBio 873. The injection of 25 or 50 μg.kg^"1 of LASSBio 873 promoted hypnosis with duration of 27.9 + 8.4 or 49.6 ± 3.9 seconds, respectively (Figure

3).

1. Analgesic Activity

In a following stage was evaluated the profile of LASSBio 872 and

LASSBio 873 to the central analgesic activity using the Hot-plate exposure assay. The average time of permanence in the plate after intraperitoneal injection of vehicle - DMSO was not much different of treatment with saline. When pre-treated with only vehicle-DMSO, the animals remained on plate for 13,9 ± 1 ,26 seconds.

The maximum time of permanence of animals on the plate was of 35 seconds in order to avoid any injury in their paws. All the compounds tested significantly increased the permanence of animals on the hot plate (Figure 4). The figure 4 shows that 5 minutes after the intraperitoneal injection of 6 and 8 mg.Kg-1 , LASSBio 872 increased the time of permanence of animals on hot plate for 29,1 ± 2,1 and 25,0 ± 1 ,7 seconds, respectively. The maximum analgesic effect was observed after 15 minutes of parenteral administration and the duration of analgesia was about 100 minutes. The same results were observed with LASSBio 873. However, LASSBio 873 was more powerful than LASSBio 872 in promoting central analgesia. After 5 minutes of administration of 4mg.kg^"1 the time of permanence on hot plate was about the maximum allowed, i.e, 32,9 ± 1,1 seconds. The duration of analgesia induced by LASSBio 873 was also bigger when compared with LASSBio872. after 2 hours of i.p. administration of LASSBio 873, the animals still presented analgesia with permanence in the hot plate of 23,3 ± 2,0 or 24,8 ± 2,0 seconds when treated with 2 or 4 mg. kg^"1.

In accordance with these results a important compound was identified, LASSBio 873, with effects in central nervous systems that could be efficient as analgesic, in many types of pain, principally those associated with tissue injury, inflammation, or tumoral development. In the same form the antinociceptive action, the LASSBio 873 also presented hypnotic effect indicating the possibility of it use as intravenous anaesthetic.

Methodologies used for the bio-tests Experiments in vivo Hypnotic activity in mice

The test called of "sleeping time" makes possible the evaluation of duration of hypnosis induced for a barbituric, the sodium pentobarbital that is administrated for intravenous delivery (i.v.) in vein of the tail of mouse, in dose of 25mg/kg mouse. The duration of hypnosis is determined from the moment of injection and loss of the mouse position. This experimental protocol makes possible the identification of substances that can intervene with time of hypnosis induced for barbituric. About 160 male Swiss mice (18 to 25 g) were distributed in 16 experimental groups. One of groups was considered control, where the DMSO was administrated separately i.p. 30 minutes before of injection of sodium pentobarbital. The administration of each compound in test in doses of 1 to 10 mg.kg^"1 was made in each experimental group and duration of hypnosis was measured. The values of time of hypnosis was compared between the groups and considered different significantly of control different (DMSO) when P<0,005. Determination of average hypnotic dose (DHsn) in mice

Male swiss mice, weighting between 18 and 25g were used by the determination of average hypnotic dose (DH₅₀). A single dose that ranged from

25 to 150 μg.kg^"1 of each test-compound was injected intravenously (i.v.) in groups of at least 10 animals. The compound was diluted in DMSO and prepared immediately before the experiments. After the administration, the animals were observed and the percentage of each group that presented hypnosis, i.e. loss of posture reflex, was determined. Graphics showing the dose with the number of occurrences of hypnosis (in percentage) were plotted. Therefore, it was possible to determine the dose that induced hypnosis in 50% of the tested animals. (DH₅₀).

Analgesic Activity - Hot-plate The central analgesic activity was evaluated using the hot plate exposure test. This test consist in placing the mouse on a metallic plate (Letica LE 7406) heated at 52 ± 0.1⁰C and counting the permanence time on the plate prior the licking of the paws, which indicates response to thermal stimulus (Kuraishi et a!., 1983). The time is determined prior to the withdrawal of the paw, in mice with or without previous treatment with the new molecules. The substances were injected i.p. in doses that ranged from 0.5 to 8 mg.kg^"1. The animal was placed on the hot-plate from 5 to 120 min after the administration of different compounds in order to determine the presence or absence of analgesic effect in a longer period of time. In the control group was injected only DMSO. 10 Swiss male mice were used, weighting between 18 and 25g for each compound tested. The results were expressed in average ± EPM of the permanence time in seconds. The Student's t-Test was used for the statistical analysis of the effects in the many tested doses when compared with the control. The differences were considered as significatives for p<0.05.

Claims

ClaimsPHARMACEUTICAL COMPOSITIONS CONTAINING 1-METHYL-3,6,7,8-TETRAHYDROPIRAZOLO[3,4-b]PIRROLO[4,3-d]PYRIDINE-6,8-DIONEDERIVATIVES, USE, AND PROCESS FOR PREPARING THEM.

1. Pharmaceutical composition characterized by comprising an active ingredient having the general formula (II):

wherein

R is, independently, hydrogen, alkyl, cycloalkyl; phenyl-W, furyl, tiophenyl, pyridinyl, pyrimidinyl, pyrrolyl, thiazolyl, quinazolyl or isoquinolyl; and W is, independently, hydrogen, ortho-alkyl, ortho-cy cloalkyl, o/Y/?o-alkoxyl, ortho-cycloalkoxyl, ortho-ihloxy], ortho-aryoxyϊ, ortho-sulfones, ortho-sulphides, ortho-sulphoxides, o/f/7O-sulfonates, o/t/io-sulfonamides, ortho-am^'me, ortho- amide, ortho-halides, ortho-carboalkoxyl, oAifΛo-carbothioalkoxyl, ortho- trihaloalkene, ortho-άano, ortho-nitro, meta-alkyl, meta-cycloalkyl, meta-alkoxyl, meta-cycloalkoxyl, meta-thioxyl, meta-aryoxyl, meta-sulfones, meta-sulphides, meta-sulphoxides, meta-sulfonates, meta-sulfonamides, meta-amine, meta- amide, meta-halides, meta-carboalkoxyl, meta-carbothioalkoxyl, meta- trihaloalkene, meta-ciano, meta-nitro, para-alkyl, para-cycloalkyl, para-alkoxyl, para-cycloalkoxyl, para-thioxyl, para-aryoxyl, para-sulfones, para-sulphides, para-sulphoxides, para-sulfonates, para-sulfonamides, para-amine, para-amide, para-halides, para-carboalkoxyl, para-carbothioalkoxyl, para-trihaloalkene, para-ciano or para-nitro; or its pharmaceutically acceptable salts, isosters, solvates and/or hydrates.

2. Pharmaceutical composition, according to claim 1 , characterized by the fact that it is 1-methyl-7-(4-nitrophenyl)-3-phenyl-3,6,7,8-tetrahydropirazolo- [3,4-b]-pirrolo-[3,4-d]-pyridine-6,8-dione or its pharmaceutically acceptable salts, isosters, solvates and/or hydrates.

3. Pharmaceutical composition, according to claim 1 , characterized by the fact that it is 1-methyl-7-(4-chlorophenyl)-3-phenyl-3,6,7,8- tetrahydropirazolo-[3,4-b]-pirrolo-[3,4-d]-pyridine-6,8-dione or its pharmaceutically acceptable salts, isosters, solvates and/or hydrates.

4. Pharmaceutical composition, according to claims 1, 2 or 3, characterized by having affinity to GABA receptors.

5. Pharmaceutical composition, according to claim 4, characterized by having affinity to GABA_A receptors.

6. Process for the production of a compound having a general formula (II):

wherein

R is, independently, hydrogen, alkyl, cycloalkyl; phenyl-W, furyl, tiophenyl, pyridinyl, pyrimidinyl, pyrrolyl, thiazolyl, quinazolyl or isoquinolyl; and

W is, independently, hydrogen, orffjo-alkyl, ortho-cycloalkyl, orfΛo-alkoxyl, or/Λo-cycloalkoxyl, ort/io-thioxyl, orf/?o-aryoxyl, ortf?o-sulfones, ortf/io-sulphides, o/t/70-sulphoxides, orf/70-sulfonates, orf/70-sulfonamides, ortho-am^'me, ortho- amide, ortho-halides, ortøo-carboalkoxyl, ortf?o-carbothioalkoxyl, ortho- trihaloalkene, ortho-clano, oπffro-nitro, meta-alkyl, meta-cycloalkyl, meta-alkoxyl, meta-cycloalkoxyl, meta-thioxyl, meta-aryoxyl, meta-sulfones, meta-sulphides, meta-sulphoxides, meifa-sulfonates, meta-sulfonamides, meta-amine, mβta- amide, meta-halides, meta-carboalkoxyl, meta-carbothioalkoxyl, meta- trihaloalkene, meta-ciano, meta-nitro, para-alkyl, para-cycloalkyl, para-alkoxyl, para-cycloalkoxyl, para-thioxyl, para-aryoxyl, para-sulfones, para-sulphides, para-sulphoxides, para-sulfonates, para-sulfonamides, para-amine, para-amide, para-halides, para-carboalkoxyl, para-carbothioalkoxyl, para-trihaloalkene, para-ciano or para-nitro; or its pharmaceutically acceptable salts, isosters, solvates and/or hydrates; characterized by comprising at least one step of: a) a phenylhydrazine condensation with a β-iminobutironitrile in water and chloridric acid; and b) hetero Diels-Alder, between a 2-heteroazadiene and a N- phenylmeleimidines functionalized.

7. Process, according to claim 6, characterized by the fact that condensation step of a phenylhydrazine with a β-iminobutironitrile, in water and chloridric acid comprises the steps of: a) addition of metalic sodium in benzene; b) addition of acetonitrile; c) addition of phenylhydrazine;

8. Process, according to claim 6, characterized by the fact that the step of hetero-Diels Alder comprises the reaction of a 2-heteroazadiene with dimethylformamide dimethylacetal.

9. Use, in the preparation of a medicament for curative or prophylactic treatment of hypnosigenic and/or algesic symptoms of mammals with action in the central nervous system, of a compound of general formula (II):

wherein

R is, independently, hydrogen, alkyl, cycloalkyl; phenyl-W, furyl, tiophenyl, pyridinyl, pyrimidinyl, pyrrolyl, thiazolyl, quinazolyl or isoquinolyl; and W is, independently, hydrogen, o/t/?o-alkyl, orf/70-cycloalkyl, ortho- alkoxyl, orf/?o-cycloalkoxyl, o/t/70-thioxyl, o/t/?o-aryoxyl, ortho-sulfones, o/t/70-sulphides, orfΛo-sulphoxides, o/t/?o-sulfonates, ortho-sulfonamides, o/t/70-amine, ortho-amide, orfήo-halides, orf/io-carboalkoxyl, ortho- carbothioalkoxyl, ortho-trihaloalkene, ortho-ciano, ortho-nltro, meta-alkyl, meta-cycloalkyl, /τ?etø-alkoxyl, meta-cycloalkoxyl, meta-thioxyl, meta- aryoxyl, meta-sulfones, meta-sulphides, meta-sulphoxides, meta- sulfonates, meta-sulfonamides, meta-amine, meta-amide, meta-halides, meta-carboalkoxyl, meta-carbothioalkoxyl, meta-trihaloalkene, meta- ciano, meta-nitro, para-alkyl, para-cycloalkyl, para-alkoxyl, para- cycloalkoxyl, para-thioxyl, para-aryoxyl, para-sulfones, para-sulphides, para-sulphoxides, para-sulfonates, para-sulfonamides, para-amine, para- amide, para-halides, para-carboalkoxyl, para-carbothioalkoxyl, para- trihaloalkene, para-ciano or para-nitro; or its pharmaceutically acceptable salts, isosters, solvates and/or hydrates.