# Patent

## Title
1H-furo[3,2-C]pyrazole compounds useful as kinase inhibitors

## Abstract

Furo[3,2-c]pyrazole derivatives of formula (I) as defined in the description, and pharmaceutically acceptable salts thereof, wherein A is an aryl or heteroaryl ring, —NHZR5 is at the ortho position to the CONH linker; —R1 and R2 are the same or different and, independently from each other, represent a hydrogen atom, or an organic residue; R3 is a hydrogen or halogen atom or an organic group; R4 is a hydrogen or halogen atom or an organic group; Z is direct bond, >C═O, or —C(═O)NH—; —R5 is hydrogen or an optionally substituted organic group or isomers, tautomers, carriers, metabolites, prodrugs, and pharmaceutically acceptable salts thereof. A process for their preparation and pharmaceutical compositions comprising them are disclosed; the compounds of the invention may be useful, in therapy, in the treatment of diseases associated with a disregulated protein kinase activity, in particular Aurora kinases activity or IGF-1R activity, like cancer.

## Background
FIELD OF THE INVENTION
The present invention relates to furo-pyrazole derivatives, to a process for their preparation, to pharmaceutical compositions comprising them, and to their use as therapeutic agents, particularly in the treatment of cancer and cell proliferation disorders.
DISCUSSION OF THE BACKGROUND
The malfunctioning of protein kinases (PKs) is the hallmark of numerous diseases. A large share of the oncogenes and proto-oncogenes involved in human cancers code for PKs. The enhanced activities of PKs are also implicated in many non-malignant diseases, such as benign prostate hyperplasia, familial adenomatosis, polyposis, neuro-fibromatosis, psoriasis, vascular smooth cell proliferation associated with atherosclerosis, pulmonary fibrosis, arthritis glomerulonephritis and post-surgical stenosis and restenosis.
PKs are also implicated in inflammatory conditions and in the multiplication of viruses and parasites. PKs may also play a major role in the pathogenesis and development of neurodegenerative disorders.
For a general reference to PKs malfunctioning or disregulation see, for instance, Current Opinion in Chemical Biology 1999, 3, 459-465.
Among the several protein kinases known in the art as being implicated in the growth of cancer cells are Aurora kinases, in particular Aurora-2.
Aurora-2 was found to be over-expressed in a number of different tumor types. Its gene locus maps at 20q13, a chromosomal region frequently amplified in many cancers, including breast [Cancer Res. 1999, 59(9), 2041-4] and colon.
20q13 amplification correlates with poor prognosis in patients with node-negative breast cancer and increased Aurora-2 expression is indicative of poor prognosis and decreased survival time in bladder cancer patients [J. Natl. Cancer Inst., 2002, 94(17), 1320-9]. For a general reference to Aurora-2 role in the abnormal centrosome function in cancer see also Molecular Cancer Therapeutics, 2003, 2, 589-595.
The insulin-like growth factor 1 receptor (IGF-1R, IGF1R) is a member of the insulin receptor subfamily of RTKs.
There exist several lines of evidence suggesting that IGF-1R signaling can contribute to tumor genesis, and that interfering with IGF-1R function represents a valid therapeutic option in cancer. Forced expression of the receptor leads to ligand-dependent transformed growth of murine and of rat fibroblasts (e.g. Kaleko M., Rutter W. J. and Miller A. D. Mol Cell Biol vol. 10, pages 464-73, 1990; Rubini M., Hongo A., D'Ambrosio C. and Baserga R. Exp Cell Res vol. 230, pages 284-92, 1997), and such transformed cells are able to form tumors in vivo, with both in vitro transformation and tumor formation in vivo being dependent upon an active kinase domain (reviewed in Blakesley V. A., Stannard B. S., Kalebic T., Helman L. J., and LeRoith D. J Endocrinol vol. 152, pages 339-44, 1997).
SUMMARY OF THE INVENTION
It is an object of the invention to provide compounds, which are useful in therapy as agents against a host of diseases caused by and/or associated to a disregulated protein kinase activity and, more particularly, Aurora kinases activity or IGF-1R activity. It is another object to provide compounds, which are endowed with protein kinase inhibiting activity and, more particularly, Aurora kinases or IGF-1R inhibiting activity. The present invention in particular relates to novel furo-pyrazole compounds, and derivatives thereof, endowed with very high Aurora-2 kinase inhibiting activity. More specifically, the compounds of this invention are useful in the treatment of a variety of cancers including, but not limited to: carcinoma such as bladder, breast, colon, kidney, liver, lung, including small cell lung cancer, esophagus, gall-bladder, ovary, pancreas, stomach, cervix, thyroid, prostate, and skin, including squamous cell carcinoma; hematopoietic tumors of lymphoid lineage, including leukemia, acute lymphocytic leukemia, acute lymphoblastic leukemia, B-cell lymphoma, T-cell-lymphoma, Hodgkin's lymphoma, non-Hodgkin's lymphoma, hairy cell lymphoma and Burkett's lymphoma; hematopoietic tumors of myeloid lineage, including acute and chronic myelogenous leukemias, myelodysplastic syndrome and promyelocytic leukemia; tumors of mesenchymal origin, including fibrosarcoma and rhabdomyosarcoma; tumors of the central and peripheral nervous system, including astrocytoma, neuroblastoma, glioma and schwannomas; other tumors, including melanoma, seminoma, teratocarcinoma, osteosarcoma, xeroderma pigmentosum, keratoxanthoma, thyroid follicular cancer and Kaposi's sarcoma.
Due to the key role of PKs and Aurora kinases in the regulation of cellular proliferation, these furo-pyrazole derivatives are also useful in the treatment of a variety of cell proliferative disorders such as, for instance, benign prostate hyperplasia, familial adenomatosis, polyposis, neuro-fibromatosis, psoriasis, vascular smooth cell proliferation associated with atherosclerosis, pulmonary fibrosis, arthritis glomerulonephritis and post-surgical stenosis and restenosis.
Accordingly, in a first embodiment, the present invention provides a compound of formula (I)




wherein

    
    
        A is an aryl or heteroaryl ring,
        NHZR5 is at the ortho position to the CONH linker;
        R1 and R2 are the same or different and, independently from each other, represent a hydrogen atom, a straight or branched C1-C3 alkyl or a group —CONH2, —CH2OR′ or —CH2NR′R′′ or, taken together with the carbon atom to which they are bonded, R1 and R2 may form a C3-C6 cycloalkyl group; R′ and R′′ are the same or different and, independently from each other, represent a hydrogen atom or a straight or branched C1-C3 alkyl group or, taken together with the nitrogen atom to which they are bonded, R′ and R′′ may form a heterocyclic ring of formula
    
    






wherein R′′′ is a hydrogen atom or a straight or branched C1-C3 alkyl group;

    
    
        R3 is a hydrogen or halogen atom or a group selected from hydroxy, cyano, straight or branched C1-C3 alkyl, C1-C6 alkylamino and C1-C3 alkoxy;
        R4 is a hydrogen or halogen atom or a group selected from hydroxy, straight or branched C1-C3 alkyl, C1-C3 alkoxy, C1-C6 alkylamino, C1-C6 dialkylamino, azetidin-1-yl, pyrrolidin-1-yl, piperidin-1-yl, (1-methyl-piperazin-4-yl), (morpholino-4-yl), (azetidin-1-yl)methyl, (pyrrolidin-1-yl)methyl, (piperidin-1-yl)methyl, (1-methyl-piperazin-4-yl)methyl, (morpholino-4-yl)methyl, (1-methyl-piperidin-4-yloxy)methyl, (C1-C6 alkylamino)methyl and (C1-C10 di-alkylamino)methyl;
        Z is direct bond, >C═O, or —C(═O)NH—;
        R5 is hydrogen or an optionally substituted group selected from C1-C6 alkyl, C1-C6 alkenyl, C3-C6 cycloalkyl, aryl, heteroaryl and saturated heteroaryl;

or isomers, tautomers, carriers, metabolites, prodrugs, and pharmaceutically acceptable salts thereof.

    
    


Accordingly, in a second embodiment, the present invention provides a method for treating cell proliferative disorders caused by and/or associated with an altered protein kinase activity, which comprises administering to a mammal in need thereof an effective amount of a compound of formula (I) as above defined.
The above method enables treatment of cell proliferative disorders caused by and/or associated with altered protein kinases, e.g. Aurora kinases or IGF-1R activity.
In a preferred embodiment of the method described above, the cell proliferative disorder is cancer.
Specific types of cancer that may be treated include carcinoma, squamous cell carcinoma, hematopoietic tumors of myeloid or lymphoid lineage, tumors of mesenchymal origin, tumors of the central and peripheral nervous system, melanoma, seminoma, teratocarcinoma, osteosarcoma, xeroderma pigmentosum, keratoxanthoma, thyroid follicular cancer, and Kaposi's sarcoma.
The present invention also includes methods of synthesizing the furo-pyrazole compounds of formula (I) and the pharmaceutically acceptable salts, as well as the pharmaceutical compositions comprising them.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description.


DETAILED DESCRIPTION OF THE INVENTION
Several heterocyclic compounds are known in the art as protein kinase inhibitors. As an example, 2-carboxamido-pyrazole and 2-ureido-pyrazole derivatives have been disclosed as protein kinase inhibitors in the international patent applications WO 01/12189, WO 01/12188, WO 02/48114 and WO 02/70515, all in the name of the Pharmacia Italia SpA.
Fused bicyclic or tricyclic compounds comprising pyrazole moieties and possessing kinase inhibitory activity have been also disclosed in WO 00/69846, WO 02/12242, WO 03/028720, WO 03/097610, WO 04/007504, WO 04/013146, US 20050026984, WO 2005095387, US 2005215612, US 2006160874 and WO 2003097609.
The compounds of formula (I) of the invention have asymmetric carbon atoms and may therefore exist as individual optical isomers, as racemic mixtures or as any other mixture comprising a majority of one of the two optical isomers, which are all to be intended as within the scope of the present invention.
Likewise, the use as an antitumor agent of all the possible isomers and their admixtures and of both the metabolites and the pharmaceutically acceptable bio-precursors (otherwise referred to as pro-drugs) of the compounds of formula (I) are also within the scope of the present invention.
Prodrugs or carriers are any covalently bonded compounds, which release the active parent drug, according to formula (I), in vivo. In cases when compounds may exist in tautomeric forms, each form is contemplated as being included within this invention whether existing in equilibrium or predominantly in one form.
As such, unless otherwise provided, when only one of the following tautomeric forms of formula (Ia) or (Ib) is indicated, the remaining one has still to be intended as comprised within the scope of the invention;




In the present description, unless otherwise specified, with the term aryl group we intend any aromatic carbocyclic ring system of 1 or 2 ring moieties, either fused or linked to each other through a single bond, for instance including phenyl, α- or β-naphthyl or biphenyl groups.
With the term heteroaryl we intend any aromatic heterocyclic ring which may comprise an optionally benzocondensed 5 or 6 membered heterocycle with from 1 to 3 heteroatoms selected among N, O or S.
Non limiting examples of heteroaryl groups according to the invention may thus include, for instance, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolyl, imidazolyl, thiazolyl, isothiazolyl, pyrrolyl, phenyl-pyrrolyl, furyl, phenyl-furyl, oxazolyl, isoxazolyl, pyrazolyl, thienyl, benzothienyl, isoindolinyl, benzoimidazolyl, quinolinyl, isoquinolinyl, 1,2,3-triazolyl, 1-phenyl-1,2,3-triazolyl, and the like.
With the term saturated heteroaryl we intend any saturated or partially unsaturated heteroaryl as above defined. Non limiting examples of 5 to 7 membered heterocycles, optionally benzocondensed or further substituted, are 1,3-dioxolane, pyran, pyrrolidine, pyrroline, imidazolidine, pyrazolidine, pyrazoline, piperidine, piperazine, morpholine, tetrahydrofuran, azabicyclononane and the like.
With the term straight or branched C1-C3 alkyl or C1-C3 alkoxy we intend any of the groups such as methyl, ethyl, n-propyl, isopropyl, methoxy, ethoxy, n-propoxy and isopropoxy.
With the term halogen atom we intend a fluorine, chlorine, bromine or iodine atom, With the term C3-C6 cycloalkyl we intend any group such as cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.
Clearly, as these same cycloalkyl groups may be formed when R1 and R2 are taken together with the carbon atom to which they are attached, cyclic spiro compounds may be thus obtained. Just as an example, when R1 and R2 together form a cyclopentyl group, derivatives having the following general formula are herewith considered:




When considering derivatives of formula (I) wherein R1 or R2 represents a group —CH2NR′R′′ and R′ and R′′ are linked together with the nitrogen atom to which they are attached, heterocyclic moieties may be thus formed as per the general formula. Just as an example, by considering R1 as hydrogen and R2 as a group —CH2NR′R′′ with R′ and R′′ linked together so as to form a pyrrolidinyl-1-yl group, compounds having the following general formula formula are herewith considered:
When considering derivatives of formula (I) wherein R1 or R2 represents a group —CH2NR′R′′ and R′ and R′′ are linked together with the nitrogen atom to which they are attached, heterocyclic moieties may be thus formed as per the general formula. Just as an example, by considering R1 as hydrogen and R2 as a group —CH2NR′R′′ with R′ and R′′ linked together so as to form a pyrrolidinyl-1-yl group, compounds having the following general formula are herewith considered:




The inventors have surprisingly found a new class of compounds of formula (I) as defined above endowed with high protein kinases inhibition activity, having as characterizing feature an aryl or heteroaryl ring on which the substituent —NHZR5 is at the ortho position to the CONH linker.
According to the meanings provided to the substituents, any of the above aryl or heteroaryl groups may be optionally further substituted in any of their free positions by one or more groups, for instance 1 to 6 groups, selected from: halogen, nitro, oxo groups (═O), carboxy, cyano, alkyl, polyfluorinated alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl; aryl, heterocyclyl, alkyl-heterocyclyl, heterocyclyl-alkyl, amino groups and derivatives thereof such as, for instance, alkylamino, dialkylamino, arylamino, diarylamino, ureido, alkylureido or arylureido; carbonylamino groups and derivatives thereof such as, for instance, formylamino, alkylcarbonylamino, alkenylcarbonylamino, arylcarbonylamino, alkoxycarbonylamino; hydroxy groups and derivatives thereof such as, for instance, alkoxy, polyfluorinated alkoxy, aryloxy, heterocylyloxy, alkylcarbonyloxy, arylcarbonyloxy, cycloalkenyloxy or alkylideneaminoxy; carbonyl groups and derivatives thereof such as, for instance, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, cycloalkyloxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl; sulfurated derivatives such as, for instance, alkylthio, arylthio, alkylsulfonyl, arylsulfonyl, alkylsulfinyl, arylsulfinyl, arylsulfonyloxy, aminosulfonyl, alkylaminosulfonyl or dialkylaminosulfonyl.
In their turn, whenever appropriate, each of the above substituents may be further substituted by one or more of the aforementioned groups.
With the term alkyl or alkoxy group we intend, unless otherwise provided, any straight or branched C1-C6 alkyl or alkoxy group, hence comprehensive of the aforementioned C1-C3 alkyl or alkoxy groups and also comprising n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy, n-pentyloxy, n-hexyloxy, and the like.
With the term alkenyl or alkynyl group we intend, unless otherwise provided, any unsaturated straight or branched C2-C6 alkenyl or alkynyl group such as, for instance, vinyl, allyl, 1-propenyl, isopropenyl, 1-, 2- or 3-butenyl, pentenyl, hexenyl, ethynyl, 1- or 2-propynyl, butynyl, pentynyl, hexynyl, and the like.
With the term polyfluorinated alkyl or alkoxy we intend any straight or branched C1-C6 alkyl or alkoxy group as above defined, wherein more than one hydrogen atom is replaced by fluorine atoms such as, for instance, trifluoromethyl, trifluoromethoxy, 2,2,2-trifluoroethyl, 2,2,2-trifluoroethoxy, 1,2-difluoroethyl, 1,1,1,3,3,3-hexafluoropropyl-2-yl, and the like.
With the term heterocycle, heterocyclyl or heterocyclic group we also intend an optionally benzocondensed 4 to 7 membered heterocycle, hence encompassing aromatic heterocyclic groups also known as heteroaryl groups, either saturated or partially unsaturated, with from 1 to 3 heteroatoms selected among N, O and S.
Examples of these 4 or 7 membered heterocyclic groups are, for instance, 1,3-dioxolane, pyran, pyrrolidine, pyrroline, imidazoline, imidazolidine, pyrazolidine, pyrazoline, piperidine, piperazine, morpholine, tetrahydrofuran, hexamethyleneimine, 1,4-hexahydrodiazepine, azetidine, and the like.
With the term cycloalkenyl we intend any of the aforementioned C3-C6 cycloalkyl groups further comprising a double bond such as, for instance, 2-cyclopenten-1-yl, 3-cyclopenten-1-yl, 1-cyclohexen-1-yl, 2-cyclohexen-1-yl, 3-cyclohexen-1-yl, and the like. From all of the above, it is clear to the skilled man that any group which name has been identified as a composite name such as, for instance, alkylamino, dialkylamino, cycloalkylalkyl, arylalkyl, heterocyclylalkyl, alkylthio, aryloxy, arylalkyloxy, alkylcarbonyloxy and the like, has to be intended as conventionally construed from the parts to which they derive. So far, as an example, the term alkoxy-heterocyclyl-alkyl stands for a straight or branched alkyl group substituted by a heterocycle further substituted by alkoxy, wherein alkyl, heterocycle and alkoxy are as above defined. Likewise, the term alkyl-heterocyclyloxy stands for a heterocyclyloxy group further substituted by alkyl.
The term “pharmaceutically acceptable salts” embraces salts commonly used to form alkali metal salts and to form addition salts of free acids or free bases. The nature of the salt is not critical, provided that it is pharmaceutically acceptable. Suitable pharmaceutically acceptable acid addition salts of the compounds of the present invention may be prepared from an inorganic or organic acid. Examples of such inorganic acids are hydrochloric, hydrobromic, hydroiodic, nitric, carbonic, sulfuric, and phosphoric acid. Appropriate organic acids may be selected from aliphatic, cycloaliphatic, aromatic, arylaliphatic, heterocyclic, carboxylic and sulfonic classes of organic acids, examples of which are formic, acetic, trifluoroacetic, propionic, succinic, glycolic, gluconic, lactic, malic, tartaric, citric, ascorbic, glucuronic, maleic, fumaric, pyruvic, aspartic, glutamic, benzoic, anthranilic, mesylic, salicylic, p-hydroxybenzoic, phenylacetic, mandelic, embonic (pamoic), methanesulfonic, ethanesulfonic, benzenesulfonic, pantothenic, toluenesulfonic, 2-hydroxyethanesulfonic, sulfanilic, stearic, cyclohexylaminosulfonic, algenic, hydroxybutyric, galactaric and galacturonic acid. Suitable pharmaceutically acceptable base addition salts of the compounds of the present invention include metallic salts made from aluminum, calcium, lithium, magnesium, potassium, sodium and zinc or organic salts made from N,N′-dibenzylethylenediamine, chloroprocaine, choline, diethanolamine, ethylenediamine, meglumine (N-methyl-glucamine) and procaine. All of these salts may be prepared by conventional means from the corresponding compounds of the present invention, for instance by reacting them with the appropriate acid or base.
A preferred class of compounds of the invention is represented by a compound of formula (I) wherein A is an optionally further substituted thienyl, furyl, pyrrolyl or phenyl group.
More preferably, A is a phenyl group and R4 is at 4 position and represents hydrogen, halogen, methoxy, azetidin-1-yl, pyrrolidin-1-yl, piperidin-1-yl, (1-methyl-piperazin-4-yl), (morpholino-4-yl), (azetidin-1-yl)methyl, (pyrrolidin-1-yl)methyl, (piperidin-1-yl)methyl, (1-methyl-piperazin-4-yl)methyl, (morpholino-4-yl)methyl, (1-methyl-piperidin-4-yloxy)methyl, (C1-C6 alkylamino)methyl or (C1-C6 di-alkylamino)methyl.
Even more preferably, Z is >C═O.
In another preferred class of compounds of formula (I), R1 and R2 are both a methyl group or, taken together with the carbon atom to which they are attached, form a C3-C10 cycloalkyl group.
In another preferred class of compounds of formula (I), R3 represents a hydrogen or halogen atom.
For a reference to any specific compound of formula (I) of the invention, optionally in the form of a pharmaceutically acceptable salt, see the following experimental section. As formerly indicated, a further object of the present invention is represented by a process for preparing the compounds of formula (I) and the pharmaceutically acceptable salts thereof, which process comprises:
a) reacting a bi-cyclic compound of formula (II):




wherein ALK is a C1-C4 alkyl group with any suitable pyrazole nitrogen atom protecting agent;

b) acylating the resultant compound of formula (III):





wherein ALK is as defined above and Q represents any suitable pyrazole nitrogen protecting group, with a compound of formula (IV):





wherein A and R4 are as defined above and LG represents a suitable leaving group;

c) hydrolysing the alkyl ester group and removing of the protecting group Q from the resultant compound of formula (V):





wherein ALK, A, R4 and Q are as defined above;

d) reacting the resultant compound of formula (VI):





wherein A and R4 are as defined above, with a compound of formula (VII)





wherein R1, R2 and R3 are as defined above, in the presence of any suitable condensing agent;

e) reducing the nitro group of the resultant compound of formula (VIII)





wherein A, R1, R2, R3, R4 and Q are as defined above;

either

f) acylating the resultant compound of formula (IX):





wherein A, R1, R2, Ra and R4 are as defined above, with a compound of formula (X) or (XI):

R5—Z-LG  (X)

R5—NCO  (XI)

wherein Z is >C═O or —C(═O)NH—, and R5 and LG are as above defined;

g) selectively de-acylating the resultant compound of formula (XII):





wherein A, R1, R2, R3, R4 and Q are as defined above and Z is >C═O or —C(═O)NH—, by the selective hydrolysis of the ZR5 substituent on the pyrazole nitrogen so as to obtain a compound of formula (I) wherein A, R1, R2, R3 and R4 are as defined above and Z is >C═O or —C(═O)NH—,

or

f′) treating a compound of formula (IX) as defined above with a carbonyl compound of formula W—CO—Y (XIII) wherein W and Y are hydrogen atoms or an optionally substituted group selected from C1-C5 alkyl, C1-C5 cycloalkyl, aryl, heteroaryl or saturated heteroaryl, in the presence of an opportune reducing agent, so as to obtain a compound of formula (I) wherein A, R1, R2, R3 and R4 are as defined above and Z is a direct bond and, if desired or necessary,

h) converting a compound of formula (I) as defined above into a different compound of formula (I) by known reactions, or converting a compound of formula (I) as defined above into a pharmaceutically acceptable salt or converting the salt thereof into the free compound of formula (I) as defined above.

Alternatively, the compounds of the formula (I) of present invention may also be obtained by means of
i) reducing the nitro group of the compound of formula (V) as defined above, and either
j) acylating the resultant compound of formula (XIV):




wherein A, R4, ALK and Q are as defined above, with a compound of formula (X) or (XI) as defined above so as to obtain a compound of formula (XV):





wherein A, R4, R5, ALK and Q are as defined above and Z is >C═O or —C(═O)NH—; or

j′) treating a compound of formula (XIV) as defined above with a carbonyl compound of formula W—CO—Y (XIII) as described above, so as to obtain a compound of formula (XV) wherein A, R4, R5, ALK and Q are as defined above and Z is a direct bonds

k) hydrolysing the alkyl ester group and removing the protective group Q of the resultant compound of formula (XV) wherein Z is >C═O or —C(═O)NH— or a direct bond;

l) reacting the resultant compound of formula (XVI)





wherein A, R4, R5 and Z are as defined above, with a compound of formula (VII) as described above;

m) converting a compound of formula (I) as defined above into a different compound of formula (I) by known reactions, or converting a compound of formula (I) as defined above into a pharmaceutically acceptable salt or converting the salt thereof into the free compound of formula (I) as defined above.

It is to be noted that a compound of formula (I), (II), (VI), (VIII), (IX), (XVI) as above defined can be in any one of its tautomeric forms a or b, not only in the a form depicted above:




In the protected compounds, the suitable pyrazole nitrogen protecting group that Q represents may be on the nitrogen atom at position 2, even if the isomer having Q at 1 position is preferred and it is the only indicated.
The above process is an analogy process, which can be carried out according to methods known in the art.
From the above, it is clear to the person skilled in the art that if a compound of formula (I), prepared according to the above process, is obtained as an admixture of isomers, their separation into the single isomers of formula (I), carried out according to conventional techniques, is still within the scope of the present invention.
According to step (a) of the process, the furo-pyrazole derivative of formula (II) is protected, according to well-known methods, at the pyrazole nitrogen atom. As an example, the above protection may occur with an alkyl chlorocarbonate, in a suitable solvent such as tetrahydrofuran, dichloromethane, chloroform, acetonitrile, toluene or mixtures thereof, at a temperature ranging from about −5° C. to about 35° C. and for a time varying from about 30 minutes to about 72 hours, in the presence of an opportune proton scavenger such as triethylamine or diisopropylethylamine.
According to step (b) of the process, the compound of formula (III) is then reacted with any suitable acylating agent of formula (IV) so as to yield the compound of formula (V), by working according to methods well known in the art for the preparation of carboxamido derivatives. Typically, within the compound of formula (IV), LG represents a halogen atom and, even more preferably, a bromine or chlorine atom.
The reaction is carried out in a suitable solvent such as, for instance, tetrahydrofuran, dimethylformamide, dichloromethane, chloroform, acetonitrile, toluene or mixtures thereof, at a temperature ranging from about −10° C. to reflux and for a time varying from about 30 minutes to about 96 hours, in the presence of an opportune proton scavenger such as triethylamine, N,N-diisopropylethylamine or pyridine.
From the above, it is clear to the skilled person that the above protection at the pyrazole nitrogen atom, in step (a), is of particular advantage as it prevents that acylation with the compound of formula (IV), in step (b), occurs at the pyrazole nitrogen atom.
According to step (c) of the process, the carboxyester function of the compound of formula (V) is hydrolysed so as to yield the corresponding carboxy group and, at the same time, protective group Q is removed.
The reaction is carried out under alkaline conditions, preferably by treatment with aqueous sodium or potassium hydroxide in the presence of a suitable co-solvent such as methanol or ethanol, by operating at a temperature ranging from room temperature to the reflux temperature of the mixture and for a suitable time, for instance up to 72 hours.
According to step (d) of the process, the compound of formula (VI) is then reacted with a suitable amino derivative of formula (VII) so as to lead to the corresponding compound of formula (VIII).
From the above it is clear to the skilled person that this reaction may be accomplished in a variety of ways and operative conditions, which are widely known in the art for the preparation of carboxamides.
As an example, the reaction between the compounds of formula (VI) and (VII) can be carried out in the presence of a coupling agent such as, for instance, 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU), 1,3-dicyclohexylcarbodiimide, 1,3-diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, N-cyclohexylcarbodiimide-N′-propyloxymethyl polystyrene or N-cyclohexylcarbodiimide-N′-methyl polystyrene, in a suitable solvent such as, for instance, dichloromethane, chloroform, tetrahydrofuran, diethyl ether, 1,4-dioxane, acetonitrile, toluene, or N,N-dimethylformamide at a temperature ranging from about −10° C. to reflux and for a suitable time, for instance from about 30 minutes to about 96 hours. The said reaction is optionally carried out in the presence of a suitable catalyst, for instance 4-dimethylaminopyridine, or in the presence of a further coupling reagent such as N-hydroxybenzotriazole.
Alternatively, this same reaction can be also carried out, for example, through a mixed anhydride method, by using an alkyl chloroformate such as ethyl, iso-butyl, or iso-propyl chloroformate, in the presence of a tertiary base such as triethylamine, N,N-diisopropylethylamine or pyridine, in a suitable solvent such as, for instance, toluene, dichloromethane, chloroform, tetrahydrofuran, acetonitrile, diethyl ether, 1,4-dioxane, or N,N-dimethylformamide, at a temperature ranging from about −30° C. to room temperature.
According to step (e) of the process, the aromatic nitro group of the compound of formula (VIII) is reduced to amino. The reaction may be carried out in a variety of way and operative conditions, which are widely known in the art for reducing a nitro to an amino group. Preferably, this reaction is carried out in a suitable solvent such as, for instance, water, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, ethyl acetate, or a mixture thereof, in the presence of a suitable reducing agent, such as, for instance, hydrogen and a hydrogenation catalyst, or by treatment with cyclohexene or cyclohexadiene and a hydrogenation catalyst, or by treatment with tin (II) chloride, or by treatment with In and hydrochloric acid, or by treatment with sodium hypophosphite and a hydrogenation catalysts at a temperature ranging from 0° C. to reflux and for a time varying from about 1 hour to about 96 hours. The hydrogenation catalyst is usually a metal, most often palladium, which can be used as such or supported on carbon. According to step (f) of the process, the compound of formula (IX) is then reacted with any suitable acylating agent of formula (X) or (XI) so as to yield compounds of formula (XII), by working according to methods well known in the art for the preparation of carboxamido and ureido derivatives. Typically, within the compound of formula (X), LG represents a halogen atom, preferably a chlorine atom, or a 2,4-dinitro-phenoxy group. The reaction is carried out in a suitable solvent such as, for instance, tetrahydrofuran, dimethylformamide, dichloromethane, chloroform, acetonitrile, toluene or mixtures thereof, at a temperature ranging from about −10° C. to reflux and for a time varying from about 30 minutes to about 96 hours. If needed, the reaction is carried out in the presence of an opportune proton scavenger such as triethylamine, N,N-diisopropylethylamine or pyridine.
According to step g) of the process, the compound of formula (XII) is then de-acylated at the pyrazole nitrogen atom under basic conditions and by working according to conventional techniques, for instance by treatment with aqueous sodium or potassium hydroxide in the presence of a suitable co-solvent such as methanol, ethanol, dimethylformamide, 1,4-dioxane, or by treatment with a tertiary amine such as triethylamine or N,N-diisopropylethylamine and by using an alcohol like methanol or ethanol as the solvent.
The reaction may occur at a temperature ranging from about 18° C. to refluxing temperature of the solvent, for a time varying from about 30 minutes to about 72 hours. Finally, according to step f′) of the process, the reaction between a compound of Formula (IX) and an aldehyde or a ketone can be carried out in a variety of ways, according to conventional methods for carrying out reductive alkylation, to give a compound of formula (I) wherein Z is a direct bond. Preferably, this reaction is carried out in a suitable solvent such as, for instance, methanol, N,N-dimethylformamide, dichloromethane, tetrahydrofuran, or a mixture thereof, in the presence of a suitable reducing agents such as, for instance, sodium borohydride, tetra-alkylammonium borohydride, sodium cyano borohydride, sodium triacetoxyborohydride, tetramethylammonium triacetoxy borohydride, hydrogen and a hydrogenation catalyst, and in the presence of an acid catalyst, such as, for instance, acetic acid, trifluoroacetic acid, at a temperature ranging from about 0° C. to reflux and for a time varying from about 1 hour to about 96 hours.
According to step (i) of the process, the aromatic nitro group of the compound of formula (V) is reduced to amino. The reaction may be carried out as described before for step e) above.
According to step j) of the process, the compound of formula (XIV) is then reacted with any suitable acylating agent of formula (X) or (XI) so as to yield compounds of formula (XV), by working as described before for step e) above.
According to step j′) of the process, the reaction between a compound of Formula (XIV) and an aldehyde or a ketone can be carried out in a variety of ways, according to conventional methods for carrying out reductive alkylation, to give a compound of formula (XV) wherein Z is a direct bond. Preferably, this reaction is carried out as described before for step f′) above.
According to step (k) of the process, the carboxyester function of the compound of formula (XVI) is hydrolysed so as to yield the corresponding carboxy group and, at the same time, protective group Q is removed. The reaction is carried out as described before for step c) above.
Finally according to step (k) of the process, the compound of formula (XVI) is then reacted with a suitable amino derivative of formula (VII) so as to lead to the corresponding compound of formula (I).
From the above it is clear to the skilled person that this reaction may be accomplished in a variety of ways and operative conditions, which are widely known in the art for the preparation of carboxamides.
As an example, the reaction between the compounds of formula (XVI) and (VII) can be carried out as described before for step d) above.
All of the starting compounds of formula (II), (IV), (VII), (VIII), (X), (XI) and (XIII) are known or can be obtained according to known methods.
For a reference to the preparation of the compounds of formula (II) see WO 2004007504, as well as the following experimental section.
Pharmacology
The compounds of formula (I) are active as protein kinase inhibitors, more particularly as Aurora kinases inhibitors or IGF-R1 inhibitors and are therefore useful, for instance, to restrict the unregulated proliferation of tumor cells.
In therapy, they may be used in the treatment of various tumors, such as those formerly reported, as well as in the treatment of other cell proliferative disorders such as psoriasis, vascular smooth cell proliferation associated with atherosclerosis and post-surgical stenosis and restenosis.
The inhibiting activity and the potency of selected compounds is determined through a method of assay based on the use of the SPA technology (Amersham Pharmacia Biotech).
The assay consists of the transfer of radioactivity labelled phosphate moiety by the kinase to a biotinylated substrate. The resulting 33P-labelled biotinylated product is allowed to bind to streptavidin-coated SPA beads (biotin capacity 130 pmol/mg), and light emitted was measured in a scintillation counter.
Inhibition Assay for IGF-1R Kinase Activity
The buffers/components used in the assay were as follows. Kinase Buffer (buffer KB) was composed of 50 mM HEPES, 3 mM MnCl2, 1 mM DTT, 3 microM Na3VO4, pH 7.9. Enzyme Buffer (buffer EB) was composed of buffer KB containing 0.6 mg/ml BSA (bovine serum albumin). SPA scintillation beads (Product Code Number RPNQ0007, Amersham Biosciences, Piscataway, N.J. USA) were prepared as a 10 mg/ml suspension in PBS containing 32 mM EDTA, 500 microM unlabeled ATP, and 0.1% Triton X-100. This preparation is referred to below as “SPA bead suspension”. On the day of assay, IGF-1R was pre-phosphorylated in order to linearize reaction kinetics. To achieve this, the desired quantity of enzyme was incubated for 30 min at 28° C. at a concentration of 1050 nM enzyme in buffer EB containing 100 microM unlabeled ATP. After preincubation, and immediately before assay, this pre-phosphorylated IGF-1R kinase preparation was diluted to an enzyme concentration of 60 nM by addition of 16.5 volumes of buffer KB. This diluted prephosphorylated enzyme is referred to below as “enzyme mix”.
The substrate used in the assay was a carboxy-terminally biotinylated peptide of the following sequence: KKKSPGEYVNIEFGGGGGK-biotin. The peptide was obtained in batches of >95% peptide purity from American Peptide Company, Inc. (Sunnyvale, Calif., USA). “ATP Mix”, referred to below, consisted of buffer KB containing 6 nM 33Pg-ATP (gamma phosphate-labeled, RedivueTM Code Number AH9968, 1000-3000 Ci/mmole, Amersham Biosciences Piscataway, N.J. USA), 18 microM unlabeled ATP, and 30 microM biotinylated substrate peptide. This solution contained these components at 3× their final reaction concentrations. Compounds to be tested were prepared in 100% DMSO at appropriate concentrations. These preparations were then diluted 33-fold using buffer KB, so as to obtain compound at 3× the desired final assay concentration in buffer KB containing 3% DMSO. This 3× preparation is referred to below as “compound working solution”.
Kinase reaction: Reactions were performed in 96-well U-bottom microtiter plates (such as Product #650101, Greiner Bio-One, Kremsmuenster Austria) in a final reaction volume of 30 microL. To each test well were added 10 microL of “compound working solution” containing appropriate dilution of compound, followed by 10 microL “ATP Mix” and 10 microL “Enzyme Mix”, thus starting the reaction. Well contents were immediately mixed by pipetting, and reactions were incubated for 60 minutes at room temperature. After incubation, reactions were stopped by adding 100 microL/well “SPA bead suspension”. Wells were incubated a further 15 minutes at room temperature, then 110 microL were withdrawn from each well and transferred to separate wells of 96-well opaque scintillation counting plates (such as OptiPlateTM-96, PerkinElmer LAS, Inc. Boston, Mass., USA), each containing 100 microL/well 5M CsCl. After 4 hours resting at room temperature to allow SPA bead floatation, these plates were read using a scintillation counter (Packard TopCount NXT, PerkinElmer LAS, Inc. Boston, Mass., USA) in order to quantitate the light emitted from each well (proportional to the amount of phosphate incorporated into the substrate peptide during kinase reaction).
Many of the steps described above, such as those involving compound dilution, addition of mixes to the reaction, and transfer of completed reaction to counting plates can be automated using robotized pipetting stations (such as Multimek and Biomek liquid handlers, Beckman Coulter Inc.,
Fullerton Calif. USA), and a dilution curve of a known kinase inhibitor such as staurosporine can be routinely included as a positive control for IGF-1R inhibition.
Results: data were analysed using the “Assay Explorer” software package (Elsevier MDL, San Leandro, Calif. 94577). For single compound concentrations, inhibitory activity was typically expressed as expressed as % inhibition obtained in presence of compound, compared to total activity of enzyme obtained when inhibitor is omitted. Compounds showing desired inhibition can be further analysed in order to study the potency of the inhibitor through IC50 calculation. In this case, inhibition data obtained using serial dilutions of the inhibitor can be fitted by non-linear regression using the following equation:




  v
  =
  
    
      v
      0
    
    +
    
      
        (
        
          
            v
            0
          
          -
          
            v
            b
          
        
        )
      
      
        1
        +
        
          10
          
            n
            ⁡
            
              (
              
                
                  log
                  ⁢
                  
                    
                  
                  ⁢
                  
                    IC
                    50
                  
                
                -
                
                  log
                  ⁡
                  
                    [
                    I
                    ]
                  
                
              
              )
            
          
        
      
    
  




where vb is the baseline velocity, v is the observed reaction velocity, vo is the velocity in the absence of inhibitors, and [I] is the inhibitor concentration.

Western Blot Analysis of Receptor Phosphorylation Following Stimulation with IGF-1 in MCF-7 Human Breast Cancer Cells

MCF-7 cells (ATCC# HTB-22) were seeded in 12-well tissue culture plates at 2×10^5 cells/well in E-MEM medium (MEM+Earle's BSS+2 mM glutamine+0.1 mM non-essential amino acids)+10% FCS, and incubated overnight at 37° C., 5% CO2, 100% relative humidity. Cells were then starved by replacing E-MEM+10% FCS with E-MEM+0.1% BSA, and incubating overnight. After this incubation, wells were treated with desired concentrations of compound for 1 hour at 37° C., and were then stimulated with 10 nM recombinant human IGF-1 (Invitrogen, Carlsbad, Calif., USA) for 10 minutes at 37° C. Cells were then washed with PBS and lysed in 100 microL/well cell lysis buffer (M-PER Mammalian Protein Extraction Reagent [Product #78501, Pierce, Rockford, Ill., USA]+10 mM EDTA+Protease inhibitor cocktail [Sigma-Aldrich product #P8340]+phosphatase inhibitor cocktail [Sigma-Aldrich products #P2850+#P5726]). Cell lysates were cleared by centrifugation at 10,000×g for 5 minutes, and 10 microg/lane of cleared lysate protein were run on NuPAGE gels (NuPAGE 4-12% 10-lane Bis-Tris gels, Invitrogen) with MOPS running buffer, then transferred onto Hybond-ECL nitrocellulose filters (Amersham Biosciences, Little Chalfont, Buckinghamshire, UK) using Mini PROTEAN II chambers (Bio-Rad Laboratories, Hercules, Calif., USA). Filters bearing transferred protein were incubated for 1 hour in blocking buffer (TBS+5% BSA+0.15% Tween 20), and probed for 2 hours in the same buffer containing 1/1000 rabbit anti-phospho IGF-1R Tyr1131/InsR Tyr 1146 antibody (product #3021, Cell Signaling Technology, Beverly, Mass., USA) for the detection of phosphorylated IGF-1R, or 1/1000 dilution of rabbit IGF-Irβ(H-60) antibody (product #sc-9038, Santa Cruz Biotechnology, Inc., Santa Cruz, Calif., USA) for detecting total IGF-1Rβ chain. In either case, filters were then washed for 30 minutes with several changes of TBS+0.15% Tween 20, and incubated for 1 hour in washing buffer containing 115000 dilution of horseradish peroxidase conjugated anti-rabbit IgG (Amersham, product #NA934), then were washed again and developed using the ECL chemiluminescence system (Amersham) according to manufacturers recommendations. Unless otherwise stated, reagents used were from Sigma-Aldrich, St. Louis, Mo., USA.
Growth Factor Induced S6 Ribosomal Protein Phosphorylation in Primary Human Fibroblasts.
Phosphorylation of S6 ribosomal protein in response to growth factor stimulation of normal human dermal fibroblasts (NHDF) was used to assess compound potency in inhibiting IGF-1 induced signal transduction in cells, and selectivity towards EGF and PDGF stimulus. NHDF cells obtained from PromoCell (Heidelberg, Germany), were maintained at 37° C. in a humidified atmosphere with 5% CO2 in complete Fibroblast Growth Medium (PromoCell). For assay, NHDF were seeded in 384-well tissue culture plates (clear- and flat-bottomed black plates; Matrix Technologies Inc., Hudson, N.H., USA) at a density of 5000 cells/well in serum-free medium containing 0.1% bovine serum albumin (BSA) and incubated for 5 days. Starved cells were treated for 1 hour with desired doses of compounds and then stimulated for a further 2 hours with either 10 nM IGF-1 (Invitrogen Corp., CA, USA), 10 nM EGF (Gibco BRL, USA) or 1 nM PDGF-B/B (Roche Diagnostics GmbH, Germany). Cells were then fixed in PBS/3.7% paraformaldehyde for 20 minutes at room temperature, washed ×2 with PBS, and permeabilized with PBS/0.3% Triton X-100 for 15 minutes. Wells were then saturated with PBS/1% non-fat dry milk (Bio-Rad Laboratories, Hercules, Calif., USA) for 1 hour, and then probed for 1 hour at 37° C. with anti-phospho-S6 (Ser 2351236) antibody (Cell Signaling Technology, Beverly, Mass., USA, cat. #2211) at 1/200 dilution in PBS/1% milk/0.3% Tween 20. Wells were then washed twice with PBS, and incubated for 1 hour at 37° C. with PBS/1% milk/0.3% Tween 20+1 microg/mL DAPI (4,6-diamidino-2-phenylindole)+ 1/500 Goat anti-rabbit Cy5TM-conjugated secondary antibody (Amersham Biosciences, Little Chalfont, Buckinghamshire, UK). Wells were then washed ×2 with PBS, and 40 microL PBS are left in each well for immunofluorescence analysis. Fluorescence images in the DAPI and Cy5TM channels were automatically acquired, stored and analysed using a Cellomics ArrayScanTM IV instrument (Cellomics, Pittsburgh, USA); the Cellomics Cytotoxicity Algorithm was used to quantify cytoplasmic fluorescence associated with phospho-S6 (Cy5TM signal parameter: “Mean Lyso Mass-pH”) for each cell in 10 fields/well, and eventually expressed as a mean population value. Unless otherwise stated, reagents were obtained from Sigma-Aldrich, St. Louis, Mo., USA.
Inhibition Assay of Aurora-2 Activity
Kinase reaction: 8 μM biotinylated peptide (4 repeats of LRRWSLG), 10 μM ATP (0.5 uCi P33γ-ATP), 7.5 ng Aurora 2, inhibitor in a final volume of 30 μl buffer (HEPES 50 mM pH 7.0, MgCl2 10 mM, 1 mM DTT, 0.2 mg/mL BSA, 3 μM orthovanadate) were added to each well of a 96 U bottom well plate. After 60 minutes at room temperature incubation, reaction was stopped and biotinylated peptide captured by adding 100 μl of bead suspension.
Stratification: 100 μl of CsCl 5 M were added to each well and let stand 4 hour before radioactivity was counted in the Top-Count instrument.
IC50 determination: inhibitors were tested at different concentrations ranging from 0.0015 to 10 μM. Experimental data were analyzed by the computer program GraphPad Prizm using the four parameter logistic equation:

y=bottom+(top−bottom)/(1+10^((log IC50−x)*slope))

where x is the logarithm of the inhibitor concentration, y is the response; y starts at bottom and goes to top with a sigmoid shape.

Ki Calculation:

Experimental method, Reaction was carried out in buffer (10 mM Tris, pH 7.5, 10 mM MgCl2, 0.2 mg/mL BSA, 7.5 mM DTT) containing 3.7 nM enzyme, histone and ATP (constant ratio of cold/labeled ATP 1/3000). Reaction was stopped with EDTA and the substrate captured on phosphomembrane (Multiscreen 96 well plates from Millipore). After extensive washing, the multiscreen plates were read on a top counter. Control (time zero) for each ATP and histone concentrations was measured.
Experimental design: Reaction velocities are measured at four ATP, substrate (histone) and inhibitor concentrations. An 80-point concentration matrix was designed around the respective ATP and substrate Km values, and the inhibitor IC50 values (0.3, 1, 3, 9 fold the Km or IC50 values). A preliminary time course experiment in the absence of inhibitor and at the different ATP and substrate concentrations allows the selection of a single endpoint time (10 min) in the linear range of the reaction for the Ki determination experiment.
Kinetic parameter estimates: Kinetic parameters were estimated by simultaneous nonlinear least-square regression using [Eq. 1] (competitive inhibitor respect to ATP, random mechanism) using the complete data set (80 points):




  
    
      
        v
        =
        
          
            Vm
            ·
            A
            ·
            B
          
          
            
              
                
                  
                    α
                    ·
                    Ka
                    ·
                    Kb
                  
                  +
                  
                    α
                    ·
                    Ka
                    ·
                    B
                  
                  +
                
              
            
            
              
                
                  
                    a
                    ·
                    Kb
                    ·
                    A
                  
                  +
                  
                    A
                    ·
                    B
                  
                  +
                  
                    α
                    ·
                    
                      Ka
                      Ki
                    
                    ·
                    I
                    ·
                    
                      (
                      
                        Kb
                        +
                        
                          B
                          β
                        
                      
                      )
                    
                  
                
              
            
          
        
      
    
    
      
        [
        
          Eq
          ⁢
          .1
        
        ]
      
    
  




where A=[ATP], B=[Substrate], I=[inhibitor], Vm=maximum velocity, Ka, Kb, Ki the dissociation constants of ATP, substrate and inhibitor respectively. α and β the cooperativity factor between substrate and ATP binding and substrate and inhibitor binding respectively.
The compounds of the invention were further tested, in vitro to assess the anti-proliferative effect onto cell cultures.
In Vitro Cell Proliferation Assay
The human colon cancer cell line HCT-116 was seeded at 5000 cells/cm2 in 24 wells plate (Costar) using F12 medium (Gibco) supplemented with 10% FCS (EuroClone, Italy) 2 mM L-glutamine and 1% penicillin/streptomycin and maintained at 37° C., 5% CO2 and 96% relative humidity. The following day, plates were treated in duplicates with 5 ul of an appropriate dilution of compounds starting from a 10 mM stock in DMSO. Two untreated control wells were included in each plate. After 72 hours of treatment, medium was withdrawn and cells detached from each well using 0.5 mL of 0.05% (w/v) Trypsin, 0.02% (w/v) EDTA (Gibco) Samples were diluted with 9.5 mL of Isoton (Coulter) and counted using a Multisizer 3 cell counter (Beckman Coulter). Data were evaluated as percent of the control wells,

% of CTR=(Treated−Blank)/(Control−Blank).

IC50 values were calculated by LSW/Data Analysis using Microsoft Excel sigmoidal curve fitting.

Given the above assays, the compounds of formula (I) of the invention resulted to possess a remarkable protein kinase inhibitory activity, e.g. Aurora-2 inhibitory activity. See, as an example, the following table I reporting the experimental data of some representative compounds of the invention being tested as Aurora-2 kinase inhibitors (IC50 nM) and for their cell antiproliferative effect (IC50 nM).







TABLE I













 










Aurora-2 inhibition
Cell Antiproliferation


Compound
IC50 (nM)
IC50 (nM)





(1)
6
5









It is to be noted that the Aurora-2 inhibitory activity of the compound (1) is surprisingly high.
The following compounds, screened according to the methods described in the pharmacology section above, were all shown to have IC50 values for Aurora-2 inhibition below 50 nM:

    3-{2-[(thiophene-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (2);
    3-{2-[(1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid [1-(2-fluoro-phenyl)-1-methyl-ethyl]-amide (5);
    3-{2-[(1-methyl-1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-e]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (7);
    3-{2-[(2-methyl-2H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (8);
    3-{2-[(1-methyl-1H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (9);
    3-(2-benzoylamino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide amide (10);
    3-{2-[(5-methyl-1H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (11);
    3-{2-[(thiazole-4-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (12),
    3-{4-(4-methyl-piperazin-1-yl)-2-[(1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (13);
    3-{4-(4-methyl-piperazin-1-yl)-2-[(1-methyl-1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (14) and
    3-{2-[(1-methyl-1H-imidazole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (15).


Moreover, the tested compounds resulted to possess also a very remarkable cell antiproliferative effect.
From all of the above, the novel compounds of formula (I) of the invention appear to be endowed with a biological profile, considered as a whole, which is unexpectedly superior to that of the prior art and, hence, are particularly advantageous, in therapy, against proliferative disorders associated with an altered kinase activity, in particular altered Aurora-2 kinase activity.
The compounds of the present invention can be administered either as single agents or, alternatively, in combination with known anticancer treatments such as radiation therapy or chemotherapy regimen in combination with cytostatic or cytotoxic agents, antibiotic-type agents, alkylating agents, antimetabolite agents, hormonal agents, immunological agents, interferon-type agents, cyclooxygenase inhibitors (e.g. COX-2 inhibitors), matrixmetalloprotease inhibitors, telomerase inhibitors, tyrosine kinase inhibitors, anti-growth factor receptor agents, anti-HER agents, anti-EGFR agents, anti-angiogenesis agents (e.g. angiogenesis inhibitors), farnesyl transferase inhibitors, ras-raf signal transduction pathway inhibitors, cell cycle inhibitors, other cdks inhibitors, tubulin binding agents, topoisomerase I inhibitors, topoisomerase II inhibitors, and the like.
If formulated as a fixed dose, such combination products employ the compounds of this invention within the dosage range described below and the other pharmaceutically active agent within the approved dosage range.
Compounds of formula (I) may be used sequentially with known anticancer agents when a combination formulation is inappropriate.
The compounds of formula (I) of the present invention, suitable for administration to a mammal, e.g., to humans, can be administered by the usual routes and the dosage level depends upon the age, weight, and conditions of the patient and administration route.
For example, a suitable dosage adopted for oral administration of a compound of formula (I) may range from about 10 to about 500 mg per dose, from 1 to 5 times daily. The compounds of the invention can be administered in a variety of dosage forms, e.g., orally, in the form tablets, capsules, sugar or film coated tablets, liquid solutions or suspensions; rectally in the form suppositories; parenterally, e.g., intramuscularly, or through intravenous and/or intrathecal and/or intraspinal injection or infusion.
The present invention also includes pharmaceutical compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof in association with a pharmaceutically acceptable excipient, which may be a carrier or a diluent.
Another object is therefore the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof, as defined above, in the manufacture of a medicament for treating a disease caused by and/or associated with a dysregulated protein kinase activity, in particular for treating a disease caused by and/or associated with a dysregulated IGF-1R or Aurora kinases activity, preferably with a dysregulated Aurora kinase activity. Such medicament also provides tumor angiogenesis and metastasis inhibition.
The treated disease is preferably selected from the group consisting of cancer, cell proliferative disorders, viral infections, retinopathies including diabetic and neonatal retinopathies and age related macular degeneration, atherosclerosis and conditions involving vascular smooth muscle proliferation or neointimal formation such as restenosis following angioplasty or surgery, graft vessel disease, such as can occur following vessel or organ transplantation, acromegaly and disorders secondary to acromegaly as well as other hypertrophic conditions in which IGF/IGF-1R signalling is implicated, such as benign prostatic hyperplasia, psoriasis, fibrotic lung disease, pulmonary fibrosis, pathologies related to chronic or acute oxidative stress or hyperoxia induced tissue damage, and metabolic disorders in which elevated IGF levels or IGF-1R activity are implicated, such as obesity.
Another object of the present invention is the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof, as defined above, in the manufacture of a medicament with antitumor activity.
According to the invention, the treated cancer is selected from the group consisting of carcinoma, squamous cell carcinoma, hematopoietic tumors of myeloid or lymphoid lineage, tumors of mesenchymal origin, tumors of the central and peripheral nervous system, melanoma, seminoma, teratocarcinoma, osteosarcoma, xeroderma pigmentosum, keratocanthomas, thyroid follicular cancer and Kaposi's sarcoma.
Moreover, the treated cancer can be selected from the group consisting of breast cancer, lung cancer, colorectal cancer, prostate cancer, ovarian cancer, endometrial cancer, gastric cancer, clear cell renal cell carcinoma, uveal melanoma, multiple myeloma, rhabdomyosarcoma, Ewing's sarcoma, Kaposi' sarcoma and medulloblastoma.
The treated cell proliferative disorder is selected from the group consisting of benign prostate hyperplasia, familial adenomatosis polyposis, neuro-fibromatosis, psoriasis, vascular smooth cell proliferation associated with atherosclerosis, pulmonary fibrosis, arthritis, glomerulonephritis and post-surgical stenosis and restenosis.
The pharmaceutical compositions containing the compounds of the invention are usually prepared following conventional methods and are administered in a suitable pharmaceutical form.
For example, the solid oral forms may contain, together with the active compound, diluents, e.g., lactose, dextrose saccharose, sucrose, cellulose, corn starch or potato starch; lubricants, e.g., silica, talc, stearic acid, magnesium or calcium stearate, and/or polyethylene glycols; binding agents, e.g., starches, arabic gum, gelatine methylcellulose, carboxymethylcellulose or polyvinyl pyrrolidone; disintegrating agents, e.g., starch, alginic acid, alginates or sodium starch glycolate; effervescing mixtures; dyestuffs; sweeteners; wetting agents such as lecithin, polysorbates, laurylsulphates; and, in general, non-toxic and pharmacologically inactive substances used in pharmaceutical formulations. These pharmaceutical preparations may be manufactured in known manner, for example, by means of mixing, granulating, tabletting, sugar-coating, or film-coating processes.
The liquid dispersions for oral administration may be, e.g., syrups, emulsions and suspensions.
As an example the syrups may contain, as a carrier, saccharose or saccharose with glycerine and/or mannitol and sorbitol.
The suspensions and the emulsions may contain, as examples of carriers, natural gum, agar, sodium alginate, pectin, methylcellulose, carboxymethylcellulose, or polyvinyl alcohol.
The suspension or solutions for intramuscular injections may contain, together with the active compound, a pharmaceutically acceptable carrier, e.g., sterile water, olive oil, ethyl oleate, glycols, e.g., propylene glycol and, if desired, a suitable amount of lidocaine hydrochloride.
The solutions for intravenous injections or infusions may contain, as a carrier, sterile water or preferably they may be in the form of sterile, aqueous, isotonic, saline solutions or they may contain propylene glycol as a carrier.
The suppositories may contain, together with the active compound, a pharmaceutically acceptable carrier, e.g., cocoa butter, polyethylene glycol, a polyoxyethylene sorbitan fatty acid ester surfactant or lecithin.
With the aim to better illustrate the present invention, without posing any limitation to it, the following examples are now given.
EXPERIMENTAL SECTION
The following HPLC method was used in the analysis of the compounds, as specified in the synthetic examples set forth below. As used herein, the term “Rt” refers to the retention time (minutes) for the compound using the HPLC method specified below.
LC-MS Method
HPLC/MS was performed on a Waters X Terra RP 18 (4.6×50 mm, 3.5 μm) column using a Waters 2790 HPLC system equipped with a 996 Waters PDA detector and a Micromass mod. ZQ single quadrupole mass spectrometer, equipped with an electrospray (ESI) ion source. Mobile phase A was ammonium acetate 5 mM buffer (pH 5.5 with acetic acid/acetonitrile 95:5), and Mobile phase B was water/acetonitrile (5:95). Gradient from 10 to 90% B in 8 minutes, hold 90% B 2 min. UV detection at 220 nm and 254 nm. Flow rate 1 mL/min. Injection volume 10 μl. Full scan, mass range from 100 to 800 amu. Capillary voltage was 2.5 KV; Source temperature was 120° C.; Cone was 10 V. Retention Times (LC-MS Rt) are given in minutes at 220 nm or 254 nm. Mass are given as m/z ratio.
Example 1
3-Amino-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester




A solution of ethyl chlorocarbonate (4.90 mL, 51.7 mmol) in tetrahydrofuran (THF, 60 mL) was slowly added to a mixture of 3-Amino-1H-furo[3,2-c]pyrazole-5-carboxylic acid propyl ester (12.0 g, 50.2 mmol) and diisopropylethylamine (DIEA, 51.5 mL, 301 mmol) in THF (300 mL), maintaining the temperature between −5 and −10° C. The reaction was kept at the same temperature for 5 minutes then allowed to reach room temperature. The obtained mixture was evaporated to dryness under vacuum and the residue extracted with ethyl acetate (AcOEt) and water. The organic layer was separated, dried over sodium sulphate and evaporated to dryness. The resulting raw material was triturated with diethyl ether to give 13.7 g of the title compound as a white solid.
LC-MS: Rt 4.87; [M+H]+ 282. 1H NMR (400 MHz, DMSO-D6) δ ppm 0.97 (t, 3H) 1.35 (t, 3H) 1.67-1.81 (m, 2H) 4.28 (t, 2H) 4.36 (q, 2H) 6.35 (s, 2H) 7.39 (s, 1H).
Example 2
3-(2-Nitro-benzoylamino)-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester




To a solution of 3-amino-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester (500 mg, 1.606 mmol) and diisopropylethylamine (DIEA, 0.824 mL, 4.818 mmol) in tetrahydrofuran (THF, 20 mL) at 0° C., 2-nitro-benzoyl chloride (0.318 mL, 2.409 mmol) was added. The reaction mixture was kept at the same temperature for 10 minutes then allowed to reach room temperature and let react overnight. The solvent was removed under vacuum, the residue was dissolved in dichloromethane (DCM) and washed with a 10% solution of acetic acid (AcOH), water, saturated NaHCO3 and brine. The crude was purified on silica gel (eluant dichloromethane/methanol 96/4) yielding 512 mg (69%) of the title compound.
LC-MS: Rt 7.48; [M+H]+ 431. 1H NMR (400 MHz, DMSO-D6) δ ppm 0.98 (t, 3H) 1.41 (t, 3H) 1.68-1.82 (m, 2H) 4.31 (t, 2H) 4.48 (q, 2H) 7.54 (s, 1H) 7.76-7.96 (m, 3H) 8.18 (d, 1H) 12.09 (s, 1H).
By operating in an analogous way and by reacting 3-amino-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester with the appropriate acyl chloride derivative, the following compounds was thus prepared:

    3-[4-(4-Methyl-piperazin-1-yl)-2-nitro-benzoylamino]-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester


LC-MS: Rt 4.65; [M+H]+529. 1H NMR (400 MHz, DMSO-D6) δ ppm 0.97 (t, J=7.38 Hz, 3H) 1.40 (t, J=7.07 Hz, 3H) 1.68-1.81 (m, 2H) 2.20-2.28 (m, 3H) 2.42-2.49 (m, 4H) 3.36-3.44 (m, 4H) 4.31 (q, J=6.58 Hz, 2H) 4.48 (q, J=7.07 Hz, 2H) 7.24 (dd, J=8.90, 2.44 Hz, 1H) 7.45 (d, J=2.44 Hz, 1H) 7.51-7.53 (m, 1H) 7.72 (d, J=8.78 Hz, 1H) 11.87 (s, 1H).
Example 3
3-(2-Amino-benzoylamino)-furo[3,2-c]pyrazole-5-carboxylic acid




To a solution of 3-(2-Nitro-benzoylamino)-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester (7.6 g, 0.0176 mol) in methanol (100 mL), NaOH 2N (44.1 mL, 0.0882 mmol) was added. The mixture was gently refluxed for 8 hours, then the solvent was evaporated under vacuum, and the residual aqueous solution was diluted with water and ice. Hydrochloric acid (12 N) was added until pH 2. The yellowish solid that precipitated was collected, washed with water and dried under vacuum at 60° C. 6.5 g of the title compound was so obtained.
LC-MS: Rt 1.13: [M+H]+ 317.
By operating in an analogous way and by using 3-[4-(4-Methyl-piperazin-1-yl)-2-nitro-benzoylamino]-4-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester as the starting material, the following compounds was thus prepared:

    3-[2-Amino-4-(4-methyl-piperazin-1-yl)-benzoylamino]-4-furo[3,2-c]pyrazole-5-carboxylic acid.


[M+H]+ 415.
Example 4
3-(2-Nitro-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide




3-(2-Amino-benzoylamino)-furo[3,2-c]pyrazole-5-carboxylic acid (11.6 g, 0.03668 mol) was dissolved in anhydrous dimethyl formamide (DMF, 70 mL). Diisopropylethylamine (DIEA, 31.4 mL, 0.1834 mol), cumylamine (7.43 mL, 0.055 mol) and 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU, 15.31 g, 0.0476 mol) were added respectively added. The solution was stirred at room temperature overnight. Then it was poured in a saturated solution of sodium bicarbonate (700 mL) and extracted with dichloromethane (2×250 ml). The organic layer was washed with water and dried over Na2SO4. The solution was then evaporated to dryness, taken up with toluene and evaporated to dryness, taken up with ethyl ether and filtered off. The solid was then purified by flash column chromatography on silica gel eluting with dichloromethane-methanol 46/4. The title compound was so obtained (3.87 g, 24.4% yield).
LC-MS: Rt 5.17; [M+H]+ 434. 1H NMR (400 MHz, DMSO-D6) δ ppm 1.70 (s, 6H) 7.16-7.24 (m, 1H) 7.27-7.34 (m, 2H) 7.36-7.44 (m, 3H) 7.74-7.82 (m, 2H) 7.87 (ddd, 1H) 8.15 (d, 1H) 8.18 (s, 1H) 11.29 (s, 1H) 12.50 (s, 1H).
By operating in an analogous way and by reacting 3-(2-Nitro-benzoylamino)-furo[3,2-c]pyrazole-5-carboxylic acid with the appropriate amino derivative, the following compounds were thus prepared:

    3-(2-Nitro-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid[1-(2-fluoro-phenyl)-1-methyl-ethyl]-amide.


LC-MS. Rt 5.23; [M+H]+ 452. 1H NMR (400 MHz, DMSO-D6) δ ppm 1.76 (s, 6H) 7.00-7.21 (m, 2H) 7.22-7.33 (m, 1H) 7.35-7.45 (m, 2H) 7.72-7.82 (m, 2H) 7.83-7.92 (m, 1H) 8.13 (d, 1H) 8.21 (s, 1H) 11.28 (s, 1H) 12.50 (s, 1H).

    3-(2-Nitro-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid ((R)-1-phenyl-ethyl)-amide, [M+H]+ 420;
    3-(2-Nitro-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid ((S)-1-phenyl-ethyl)-amide; [M+H]+ 420;
    3-(2-Nitro-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-phenyl-cyclopropyl)-amide; [M+H]+ 432;
    3-(2-Nitro-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid ((S)-1-phenyl-2-pyrrolidin-1-yl-ethyl)-amide; [M+H]+ 489.


By operating in an analogous way and by reacting 3-[2-Amino-4-(4-methyl-piperazin-1-yl)-benzoylamino]-furo[3,2-c]pyrazole-5-carboxylic acid with the appropriate amino derivative, the following compounds were thus prepared;

    3-[4-(4-Methyl-piperazin-1-yl)-2-nitro-benzoylamino]-1H-furo[3,2-c]pyrazole-5-carboxylic acid[1-(2-fluoro-phenyl)-1-methyl-ethyl]-amide; [M+H]+ 532.


Example 5
3-(2-Amino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide




To a solution of 3-(2-Nitro-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (1 g, 0.0023 mol) in ethanol (30 mL) tin chloride dihydrate (2.08 g, 0.00923 mol) was added. The mixture was heated to reflux for 4 hours. After cooling, the solvent was evaporated to dryness and the crude purified by flash column chromatography on silica gel (eluting with dichloromethane-methanol 4713. The isolated product was triturated with ethyl ether and dry under vacuum, furnishing 550 mg of the title compound (59% yield).
LC-MS: Rt 4.34; [M+H]+ 404; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.69 (s, 6H) 6.46-6.72 (m, J=6.95, 6.95 Hz, 3H) 6.76 (dd, 1H) 7.13-7.26 (m, 2H) 7.27-7.35 (m, 3H) 7.37-7.46 (m, 2H) 7.78 (d, J=6.71 Hz, 1H) 8.31 (s, 1H) 10.51 (s, 1H) 12.46 (s, 1H).
Alternatively the same product can be obtained by following the procedure reported below:
To a solution of 3-(2-Nitro-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (2.6 g, 0.006 mol) in ethyl acetate (200 mL) 10% Pd/C (250 mg) was added. The mixture was hydrogenated under 50 psi pressure of hydrogen using a Parr apparatus. The catalyst was renewed every 8 hours and the reaction carried out for a total of 40 hours. The catalyst was then filtered off and washed with ethyl acetate. The organic layer was evaporated under vacuum to dryness, and the solid so obtained was triturated with ethyl ether furnishing 1.49 g of the title compound.
By operating in an analogous way the following 3-(2-Amino-benzoylamino)-furo[3,2-c]pyrazole derivatives were prepared by the corresponding 3-(2-Nitro-benzoylamino)-furo[3,2-c]pyrazole derivatives:

    3-(2-Amino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid [1-(2-fluoro-phenyl)-1-methyl-ethyl]-amide LC-MS: Rt 5.13; [M+H]+ 422;


1H NMR (400 MHz, DMSO-D6) δ ppm 1.75 (s, 6H) 6.51-6.64 (m, 3H) 6.78 (d, 1H) 7.03-7.31 (m, 4H) 7.34 (s, 1H) 7.40 (ddd, 1H) 7.77 (d, 1H) 8.34 (s, 1H) 10.50 (s, 1H) 12.46 (s, 1H).

    3-(2-Amino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid ((R)-1-phenyl-ethyl)-amide, [M+H]+ 390;
    3-(2-Amino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid ((S)-1-phenyl-ethyl)-amide; [M+H]+ 390;
    3-(2-Amino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-phenyl-cyclopropyl)-amide; [M+H]+ 402;
    3-(2-Amino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid ((S)-1-phenyl-2-pyrrolidin-1-yl-ethyl)-amide; [M+H]+ 459.
    3-[2-Amino-4-(4-methyl-piperazin-1-yl)-benzoylamino]-1H-furo[3,2-c]pyrazole-5-carboxylic acid[1-(2-fluoro-phenyl)-1-methyl-ethyl]-amide;


LC-MS: Rt 3.73; [M+H]+ 502; 1H NMR (400 MHz, DMSO-d6) δ ppm 1.67 (s, 6H) 2.20 (s, 3H) 2.38-2.43 (m, 4H) 3.14-3.21 (m, 4H) 6.15 (d, J=2.44 Hz, 1H) 6.17-6.24 (m, 1H) 6.58 (br. s., 2H) 7.13-7.19 (m, 1H) 7.24-7.31 (m, 3H) 7.35-7.40 (m, 2H) 7.67 (d, J=9.02 Hz, 1H) 8.27 (s, 1H) 10.12 (s, 1H) 12.34 (br. s., 1H)
Example 6
3-{2-[(1H-Pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (1)




Pyrrole 2-carboxylic acid (0.284 g, 0.00255 mol) was dissolved in dichloromethane (DCM, 30 mL). A few drops of anhydrous dimethyl formamide (DMF) were added following the drop-wise addition of oxalyl chloride (0.0153 g, 1.34 mL). After stirring overnight at room temperature, the solvent was removed under vacuum and the mixture was taken up with toluene and evaporated to dryness (twice). This was newly dissolved in dichloromethane (DOM, 25 mL) and a solution made up of 3-(2-Amino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide (286 mg, 0.711 mmol), pyridine (4.27 mmol, 0.731 mL) and diisopropyethylamine (10.6 mmol, 0.858 mL) in dichloromethane (DOM, 30 mL) was added drop-wise. The mixture was stirred at room temperature overnight. Then, it was diluted with dichloromethane, washed respectively with a saturated solution of sodium bicarbonate, with brine with water, and then dried over sodium sulphate. The organic solvent was next evaporated to dryness and the crude taken up with toluene and evaporated to dryness. The crude was then dissolved in a 10% solution of triethylamine (TEA) in methanol and stirred at 50° C. for two hours and at room temperature overnight. The mixture was then evaporated to dryness and the residue purified by flash column chromatography on silica gel (eluting with dichloromethane-methanol 46/4). The material isolated was triturated with ethyl ether furnishing 110 mg of the title compound.
[M+H]+ 497; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.69 (s, 6H) 6.06-6.21 (m, 1H) 6.77-6.89 (m, 1H) 6.94-7.05 (m, 1H) 7.15-7.26 (m, 2H) 7.27-7.36 (m, J=12.44 Hz, 3H) 7.36-7.46 (m, 2H) 7.56-7.70 (m, 1H) 8.08 (d, 1H) 8.25 (s, 1H) 8.63 (d, 1H) 11.19 (s, 1H) 11.83 (s, 1H) 11.89-12.01 (m, 1H) 12.65 (5, 1H).
By operating as above reported and by starting from the suitable intermediate, the following Furo[3,2-c]pyrazole derivatives were analogously prepared.

    2) 3-{2-[(Thiophene-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide.


LC-MS: Rt 6.37; [M+H]+ 514; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.68 (s, 6H) 7.13 (dd, 1H) 7.20 (tt, 1H) 7.25-7.34 (m, 3H) 7.37 (s, 1H) 7.38-7.44 (m, 2H) 7.65 (ddd, 1H) 7.78 (dd, 1H) 7.84 (dd, 1H) 8.09 (d, 1H) 8.29 (s, 1H) 8.53 (d, 1H) 11.25 (s, 1H) 11.91-12.39 (m, 1H) 12.64 (s, 1H).

    3) 3-(2-Acetylamino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: Rt 4.87; [M+H]+ 446; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.68 (s, 6H) 2.09 (s, 3H) 7.10-7.24 (m, J=7.32 Hz, 2H) 7.31 (d, J=15.97 Hz, 3H) 7.36-7.45 (m, 2H) 7.54 (ddd, 1H) 7.90 (d, 1H) 8.23-8.38 (m, 2H) 10.80 (s, 1H) 11.08 (s, 1H) 12.56 (s, 1H).

    4) 3-(2-Acetylamino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid [1-(2-fluoro-phenyl)-1-methyl-ethyl]-amide


LC-MS: Rt 4.93; [M+H]+ 464; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.75 (s, 6H) 2.10 (s, 3H) 7.03-7.32 (m, 5H) 7.32-7.44 (m, 2H) 7.52-7.60 (m, 1H) 7.92 (d, 1H) 8.32 (s, 1H) 10.77-10.94 (m, 1H) 11.08 (s, 1H) 12.57 (s, 1H).

    5) 3-{2-[(1H-Pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid [1-(2-fluoro-phenyl)-1-methyl-ethyl]-amide


LC-MS: Rt 5.72; [M+H]+ 515; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.75 (s, 6H) 6.08-6.15 (m, 1H) 6.80-6.85 (m, 1H) 6.97-7.01 (m, 1H) 7.07-7.24 (m, 3H) 7.24-7.32 (m, 1H) 7.35 (s, 1H) 7.41 (ddd, 1H) 7.62 (ddd, 1H) 8.07 (d, 1H) 8.25 (s, 1H) 8.64 (d, 1H) 11.19 (s, 1H) 11.78-11.88 (m, 1H) 11.90-11.98 (m, 1H) 12.64 (s, 1H).

    6) 3-(2-Isobutyrylamino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: Rt 5.75; [M+H]+ 474; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.14 (d, J=6.83 Hz, 6H) 1.68 (s, 6H) 2.51-2.63 (m, 1H) 7.11-7.24 (m, 2H) 7.25-7.35 (m, 3H) 7.35-7.44 (m, 2H) 7.51-7.64 (m, 1H) 7.97 (d, J=7.80 Hz, 1H) 8.22 (s, 1H) 8.42 (d, J=8.29 Hz, 1H) 11.09 (s, 2H) 12.58 (s, 1H).

    7) 3-{2-[(1-Methyl-1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: RT 6.32; [M+H]+ 511; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.68 (s, 6H) 3.91 (s, 3H) 6.05 (ddd, 1H) 6.86 (ddd, 1H) 7.04 (ddd, 1H) 7.21 (s, 2H) 7.27-7.33 (m, 2H) 7.35 (s, 1H) 7.38-7.46 (m, 2H) 7.61 (ddd, 1H) 8.06 (d, 1H) 8.25 (s, 1H) 8.60 (d, 1H) 11.17 (s, 1H) 11.89 (s, 1H) 12.64 (s, 1H).

    8) 3-{2-[(2-Methyl-2H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: Rt 5.65; [M+H]+ 512; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.68 (s, 6H) 4.11 (s, 3H) 6.92 (d, 1H) 7.15-7.24 (m, 1H) 7.26-7.35 (m, 3H) 7.36 (s, 1H) 7.38-7.47 (m, 3H) 7.65 (ddd, 1H) 8.08 (d, 1H) 8.26 (s, 1H) 8.51 (d, 1H) 11.24 (s, 1H) 12.03 (s, 1H) 12.63 (s, 1H).

    9) 3-{2-[(1-Methyl-1H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: Rt 5.51; [M+H]+ 512; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.68 (s, 6H) 3.87 (s, 3H) 6.76 (d, 1H) 7.14-7.45 (m, 7H) 7.62 (ddd, 1H) 7.82 (d, 1H) 7.99 (d, 1H) 8.36 (s, 1H) 8.65 (d, 1H) 11.06 (s, 1H) 11.90 (s, 1H) 12.63 (s, 1H).

    10) 3-(2-Benzoylamino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide amide


LC-MS: Rt 6.42; [M+H]+ 508; 1H NMR (400 MHz, DMSO-D6) 5 ppm 1.66 (s, 6H) 7.16-7.24 (m, 1H) 7.25-7.34 (m, 3H) 7.35-7.45 (m, 4H) 7.47-7.61 (m, 2H) 7.67 (dt, 1H) 7.91-8.00 (m, 2H) 8.09 (d, 1H) 8.29 (s, 1H) 8.65 (d, 1H) 11.22 (s, 1H) 12.16 (s, 1H) 12.64 (s, 1H).

    11) 3-{2-[(5-Methyl-1H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: Rt 4.81; [M+H]+ 512; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.68 (s, 6H) 2.27 (s, 3H) 6.51 (s, 1H) 7.15-7.26 (m, 2H) 7.26-7.33 (m, 2H) 7.36-7.43 (m, 3H) 7.61 (dt, 1H) 7.97 (d, 1H) 8.33 (s, 1H) 8.67 (d, 1H) 11.07 (s, 1H) 11.95 (s, 1H) 12.62 (s, 1H) 13.05 (s, 1H).

    12) 3-{2-[(Thiazole-4-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: Rt 5.86; [M+H]+ 515; 1H NMR (400 MHz, DMSO-D6) δ ppm 1.68 (s, 6H) 7.19 (tt, 1H) 7.24-7.35 (m, 3H) 7.34-7.44 (m, 3H) 7.65 (dt, 1H) 8.00 (d, 1H) 8.32 (s, 1H) 8.54 (d, 1H) 8.71 (d, 1H) 9.21 (dl 1H) 11.10 (s, 1H) 12.29 (s, 1H) 12.64 (s, 1H).

    13) 3-{4-(4-Methyl-piperazin-1-yl)-2-[(1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: Rt 4.15; [M+H]+ 595; 1H NMR (400 MHz, DMSO-d6) δ ppm 1.69 (s, 6H) 2.26 (s, 3H) 2.42-2.61 (m, 4H) 3.21-3.49 (m, 4H) 6.10 (dd, 1H) 6.67-6.77 (m, 2H) 6.82 (dd, 1H) 7.00 (dd, 1H) 7.35-7.49 (m, 4H) 7.52-7.59 (m, 2H) 8.02 (d, 1H) 8.25 (br. s., 1H) 8.39 (br. s., 1H) 10.80 (s, 1H) 11.72 (br. s., 1H) 12.58 (s, 1H),

    14) 3-{4-(4-Methyl-piperazin-1-yl)-2-[(1-methyl-1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS: Rt 4.54; [M+H]+ 609; 1H NMR (400 MHz, DMSO-d6) δ ppm 1.68 (s, 6H) 2.26 (s, 3H) 2.46-2.50 (m, 4H) 3.33-3.38 (m, 4H) 3.92 (s, 3H) 6.03 (dd, J=3.84, 2.62 Hz, 1H) 6.73 (dd, J=9.08, 2.38 Hz, 1H) 6.88 (dd, J=4.02, 1.71 Hz, 1H) 7.03 (t, J=2.01 Hz, 1H) 7.15-7.23 (m, 1H) 7.25-7.33 (m, 3H) 7.37-7.43 (m, 2H) 8.02 (d, J=9.15 Hz, 1H) 8.25 (s, 1H) 8.35 (d, J=2.56 Hz, 1H) 10.78 (s, 1H) 12.56 (s, 1H).

    15) 3-{2-[(1-Methyl-1H-imidazole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


LC-MS. Rt 6.08; [M+H]+ 512; 1H NMR (400 MHz, DMSO-d6) δ ppm 1.67 (s, 6H) 4.00 (s, 3H) 7.03 (d, J=0.61 Hz, 1 H) 7.17 (t, J=7.19 Hz, 1H) 7.35 (s, 1H) 7.42 (br. s., 1H) 7.61 (ddd, J=7.90, 7.70, 1.00 Hz, 1H) 7.97 (d, J=7.68 Hz, 1H) 8.28 (s, 1H) 8.63 (d, J=8.29 Hz, 1H) 11.07 (s, 1H) 12.15 (s, 1H) 12.61 (s, 1H).

    16) 3-{2-[4-(4-Methyl-piperazin-1-yl)-benzoylamino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide


[M+H]+ 512; 1H NMR (400 MHz, DMSO-d6) δ ppm 1.68 (s, 6H) 2.50-3.77 (m, 11H) 7.12 (d, 2H) 7.16-7.27 (m, 2H) 7.27-7.34 (m, 2H) 7.37-7.44 (m, 3H) 7.59-7.68 (m, 1H) 7.85 (d, 2H) 8.07 (dd, 1H) 8.32 (br. s., 1H) 8.69 (dd, 1H) 11.24 (s, 1H) 12.12 (s, 1H) 12.65 (s, 1H).

## Claims

1. A compound of formula (I):



wherein
A is an aryl or heteroaryl ring;
NHZR5 is at the ortho position to the CONH linker;
R1 and R2 are the same or different and, independently from each other, represent a hydrogen atom, a straight or branched C1-C3 alkyl, —CONH2, —CH2OR′ or —CH2NR′R′′ or, taken together with the carbon atom to which they are bonded, R1 and R2 may form a C3-C6 cycloalkyl group; R′ and R′′ are the same or different and, independently from each other, represent a hydrogen atom or a straight or branched C1-C3 alkyl group or, taken together with the nitrogen atom to which they are bonded, R′ and R′′ may form a heterocyclic ring having one of the following formula





wherein R′′′ is a hydrogen atom or a straight or branched C1-C3 alkyl group;
R3 is a hydrogen or halogen atom or a group selected from hydroxy, cyano, straight or branched C1-C3 alkyl, C1-C6 alkylamino and C1-C3 alkoxy;
R4 is a hydrogen or halogen atom or a group selected from hydroxy, straight or branched C1-C3 alkyl, C1-C3 alkoxy, C1-C6 alkylamino, C1-C6 dialkylamino, azetidin-1-yl, pyrrolidin-1-yl, piperidin-1-yl, (1-methyl-piperazin-4-yl), (morpholino-4-yl), (azetidin-1-yl)methyl, (pyrrolidin-1-yl)methyl, (piperidin-1-yl)methyl, (1-methyl-piperazin-4-yl)methyl, (morpholino-4-yl)methyl, (1-methyl-piperidin-4-yloxy)methyl, (C1-C6 alkylamino)methyl and (C1-C6 di-alkylamino)methyl;
Z is a direct bond, —(C═O)—, or —C(═O)NH—;
R5 is hydrogen or an optionally substituted group selected from C1-C6 alkyl, C1-C6 alkenyl, C3-C6 cycloalkyl, aryl, heteroaryl and saturated heteroaryl; or optical isomers, tautomers and pharmaceutically acceptable salts thereof.

2. The compound of formula (I) as defined in claim 1 wherein R1 and R2 are not hydrogen atoms.

3. The compound of formula (I) as defined in claim 1 wherein A is an optionally further substituted thienyl, furyl, pyrrolyl or phenyl group.

4. The compound of formula (I) as defined in claim 1 wherein A is a phenyl group and R4 is at 4 position relative to the CONH linker and represents hydrogen, halogen, methoxy, azetidin-1-yl, pyrrolidin-1-yl, piperidin-1-yl, (1-methyl-piperazin-4-yl), (morpholino-4-yl), (azetidin-1-yl)methyl, (pyrrolidin-1-yl)methyl, (piperidin-1-yl)methyl, (1-methyl-piperazin-4-yl)methyl, (morpholino-4-yl)methyl, (1-methyl-piperidin-4-yloxy)methyl, (C1-C6 alkylamino)methyl or (C1-C6 di-alkylamino)methyl group.

5. The compound of formula (I) as defined in claim 1 wherein Z is —(CO)—.

6. The compound of formula (I) as defined in claim 1 wherein R1 and R2 are both a methyl group or, taken together with the carbon atom to which they are attached, form a C3-C6 cycloalkyl group.

7. The compound of formula (I) as defined in claim 1 wherein R3 represents a hydrogen or halogen atom.

8. A compound selected from the group consisting of:
3-{2-[(1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
3-{2-[(thiophene-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
3-{2-[(1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid [1-(2-fluoro-phenyl)-1-methyl-ethyl]-amide;
3-{2-[(1-methyl-1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
3-{2-[(2-methyl-2H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
3-{2-[(1-methyl-1H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
3-(2-benzoylamino-benzoylamino)-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide amide;
3-{2-[(5-methyl-1H-pyrazole-3-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
3-{2-[(thiazole-4-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
3-{4-(4-methyl-piperazin-1-yl)-2-[(1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
3-{4-(4-methyl-piperazin-1-yl)-2-[(1-methyl-1H-pyrrole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide; and
3-{2-[(1-methyl-1H-imidazole-2-carbonyl)-amino]-benzoylamino}-1H-furo[3,2-c]pyrazole-5-carboxylic acid (1-methyl-1-phenyl-ethyl)-amide;
or optical isomers, tautomers, and pharmaceutically acceptable salts thereof.

9. A process for preparing the compounds of formula (I) and the pharmaceutically acceptable salts thereof as defined in claim 1, which process comprises:
a) reacting a bi-cyclic compound of formula (II):




wherein ALK is a C1-C4 alkyl group with any suitable pyrazole nitrogen atom protecting agent;
b) acylating the resultant compound of formula (III):




wherein ALK is as defined above and Q represents any suitable pyrazole nitrogen protecting group, with a compound of formula (IV):




wherein A and R4 are as defined in claim 1 and LG represents a suitable leaving group;
c) hydrolysing the alkyl ester group and removing of the protecting group Q from the resultant compound of formula (V):




wherein ALK, A, R4 and Q are as defined above;
d) reacting the resultant compound of formula (VI):




wherein A and R4 are as defined above, with a compound of formula (VII)




wherein R1, R2 and R3 are as defined in claim 1, in the presence of any suitable condensing agent;
e) reducing the nitro group of the resultant compound of formula (VIII)




wherein A, R1, R2, R3, R4 and Q are as defined above;
either
f) acylating the resultant compound of formula (IX):




wherein A, R1, R2, R3 and R4 are as defined above, with a compound of formula (X) or (XI):


R5—Z-LG  (X)



R5—NCO  (XI)


wherein Z is —(C═O)— or —C(═O)NH—, R5 is as defined in claim 1 and LG is as above defined;
g) selectively de-acylating the resultant compound of formula (XII):




wherein A, R1, R2, R3, R4 and Q are as defined above and Z is —(C═O)— or —C(═O)NH—, by the selective hydrolysis of the ZR5 substituent on the pyrazole nitrogen so as to obtain a compound of formula (I) wherein A, R1, R2, R3 and R4 are as defined above and Z is —(C═O)— or —C(═O)NH—,
or
f) treating a compound of formula (IX) as defined above with a carbonyl compound of formula W—CO—Y (XIII) wherein W and Y are hydrogen atoms or an optionally substituted group selected from C1-C5 alkyl, C1-C5 cycloalkyl, aryl, heteroaryl or saturated heteroaryl, in the presence of an opportune reducing agent, so as to obtain a compound of formula (I) wherein A, R1, R2, R3 and R4 are as defined above and Z is a direct bond and, if desired or necessary,
h) converting a compound of formula (I) as defined above into a different compound of formula (I) by known reactions, or converting a compound of formula (I) as defined above into a pharmaceutically acceptable salt or converting the salt thereof into the free compound of formula (I) as defined above.

10. A process for preparing a compound of formula (I) as defined in claim 1, which comprises:
i) reducing the nitro group of the compound of formula (V):




and either
j) acylating the resultant compound of formula (XIV):




wherein A is an aryl or heteroaryl ring, R4 is a hydrogen or halo en atom or a group elected from hydroxy, straight or branched C1-C3 alkyl, C1-C3 alkoxy, C1-C6 alkylamino C1-C6 dialkylamino, azetidin-1-yl, pyrrolidin-1-yl, piperidin-1yl, (1-methyl-piperazin-4-yl), (morpholino-4-yl), (azetidin-1-yl)methyl, (pyrrolidin-1-yl)methyl, (piperidin-1-yl)methyl, (1-methyl-piperazin-4-yl)methyl, (morpholino-4-yl)methyl, (1-methyl-piperidin-4-yloxy)methyl, (C1-C6 alkylamino) methyl and C1-C6di-alkylamino) methyl, ALK is a C1-C4 alkyl group with any suitable pyrazole nitrogen atom protecting agent and Q represents any suitable pyrazole nitrogen protecting group, with a compound of formula (IV):




with a compound of formula (X) or (XI):


R5—Z-LG  (X)



R5—NCO  (XI)


wherein Z is —(C═O)— or —C(═O)NH—, R5 is hydrogen or an optionally substituted group selected from C1-C6 alkyl C1-C6 alkenyl, C3-C6 cycloalkyl, aryl, heteroaryl and saturated heteroaryl; or optical isomers, tautomers and pharmaceutically acceptable salts thereof and LG represents a suitable leaving group, so as to obtain a compound of formula (XV):




wherein A, R4, R5, ALK Q and Z are as defined above;
or
j′) treating a compound of formula (XIV) as defined above with a carbonyl compound of formula W—CO—Y (XIII) wherein W and Y are hydrogen atoms or an optionally substituted group selected from C1-C5 alkyl, C1-C5 cycloalkyl, aryl, heteroaryl or saturated heteroaryl, so as to obtain a compound of formula (XV) wherein A, R4, R5, ALK and Q are as defined above and Z is a direct bond;
k) hydrolysing the alkyl ester group and removing the protective group Q of the resultant compound of formula (XV) wherein Z is —(C═O)— or —C(═O)NH— or a direct bond;
l) reacting the resultant compound of formula (XVI)




wherein A, R4, R5 and Z are as defined above, with a compound of formula (VII)




wherein R1, R2 and R3 are as defined in claim 1;
m) converting a compound of formula (I) as defined above into a different compound of formula (I) by known reactions, or converting a compound of formula (I) as defined above into a pharmaceutically acceptable salt or converting the salt thereof into the free compound of formula (I) as defined above.

11. A pharmaceutical composition comprising a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof, as defined in claim 1, and at least one pharmaceutically acceptable excipient, carrier and/or diluent.

12. The pharmaceutical composition according to claim 11 further comprising one or more chemotherapeutic agents.

13. A product or kit comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof, as defined in claim 1, or a pharmaceutical composition comprising a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof, as defined in claim 1, and at least one pharmaceutically acceptable excipient, carrier and/or diluent and one or more chemotherapeutic agent, as a combined preparation for simultaneous, separate or sequential use in anticancer therapy.

14. A method of inhibiting a kinase in vitro, the kinase selected from the group consisting of Aurora kinase and IGF-1R, which comprises contacting the kinase with an effective amount of a compound of formula (I).