WO2002060534A2 - Selective alpha 1 antagonists a + d - Google Patents

Abstract

Described are derivatives with an adrenergic antagonistic activity and, in particular, high selectivity for α1a and α1d adrenergic receptors compared to α1b-receptors. This selectivity profile suggests use of these derivatives in the treatment of symptoms of the lower urinary tract, including those associated to benign prostatic hyperplasia, without the side effects associated to their hypotensive activity.

Description

TITLE

Selective Antagonists of the α,_a- and α_ld- Adrenergic Receptor

DESCRIPTION

This invention relates to α,-adrenoceptor antagonists that are selective of the expand α_ld subtypes, to pharmaceutical compositions containing them and to uses for such derivatives and compositions.

Lower-urinary-tract symptoms (LUTS) that may result from bladder-neck obstruction (BNO) is a common disorder in urology. The aetiology of LUTS can be secondary to anatomical or functional causes, or a combination of these causes.

Causes of BNO include prostatic enlargement (benign or malignant), bladder- neck contracture, urethral stricture and meatal stricture. Symptoms associated with BNO are classified as obstructive or iπitative. Obstructive symptoms include hesitancy, poor stream, prolonged urination and feelings of incomplete emptying. Iπitative symptoms consist of frequency, urgency, nocturia and unstable-bladder contractions.

The bladder is functionally and anatomically divided into the detrusor (body and ventral base) and trigone (dorsal portion of base extending between the ureteral orifices and the bladder neck). The detrusor and trigone differ in their histological, histochemical and pharmacological properties. In contrast, the trigone and prostate have similar vascular supply and innervation, and express similar receptors.

LUTS can occur secondarily to benign prostatic hypertrophy (BPH).

BPH is a progressive condition that is characterised by a nodular enlargement of both glandular (epithelial) and stromal (fibromuscular) prostatic tissue, resulting in obstruction of the urethra. The increase in stromal mass is the key factor in the pathogenesis of clinically significant BPH. The symptoms of BPH include increased frequency of urination, nocturia, a poor urinary stream and hesitancy or delay in initiating urine flow. The physiology of BPH has two components: (1) a static component related to the increase in prostatic cellular mass and (2) a dynamic component related to variations in prostatic smooth-muscle tone (Caine M. et al., 1975, Brit. J. Urol. 47: 193-202). Chronic consequences of BPH can include hypertrophy of bladder smooth muscle and a decompensated bladder, which may lead to LUTS, and an increased incidence of urinary tract infection. The specific biochemical, histological and pharmacological properties of the prostate adenoma leading to obstruction of bladder outlet are not yet known. However, the development of BPH is considered to be an inescapable phenomenon for the ageing male population. BPH is observed in approximately 70% of males over the age of 70. Cuπently, the specific method of choice for treating BPH is surgery. A pharmacological alternative to surgery is clearly very desirable. The limitations of surgery for treating BPH include the morbidity rate of an operative procedure in elderly men, persistence or recurrence of obstructive and iπitative symptoms, as well as the significant cost of surgery.

Much attention has been focused on the role of the sympathetic nervous system and α,-adrenergic receptors in the dynamic component of BNO. Clinical studies have found that ,-adrenergic antagonists relax prostatic smooth muscle, relieving obstructive symptoms (Caine M., 1990, Urol. Clin. N. Am. 17:641-649;

Lepor et al., 1992, J. Urol., 148:1467-1474).

α- Adrenergic receptors (McGrath J. C. et al., 1989, Med. Res. Rev. 9, 407-533) are specific neuroreceptor proteins located in the peripheral and central nervous systems on tissues and organs throughout the body. These receptors are important targets for controlling many physiological functions and, thus, represent important objectives for drug development. In fact, many α-adrenergic drugs have been developed over the past 40 years. Examples include clonidine, phenoxybenzamine and prazosin, terazosin, alfuzosin, doxazosin, tamsulosin (treatment of hypertension), naphazoline (nasal decongestant) and apraclonidine (treating glaucoma). α- Adrenergic drugs can be broken down into two distinct classes: agonists (clonidine and naphazoline are agonists), which mimic the receptor activation properties of the endogenous neurotransmitter noradrenaline, and antagonists (phenoxybenzamine and prazosin, terazosin, alfuzosin, doxazosin and tamsulosin are antagonists), which act to block the effects of noradrenaline. Many of these drugs are effective, but also produce unwanted side effects (for example, clonidine produces dry mouth and sedation in addition to its antihypertensive effect).

The above reported agonists are selective for the α₂-adrenergic receptor whereas most antagonists are selective for the α, -adrenergic receptor, with the exception of tamsulosin which shows a considerable affinity also for the 5-HT,_A receptor. Many of the cited α, antagonists are currently used for the therapy of BPH but, due to their poor uroselectivity, they are liable to cause cardiovascular side effects.

Recent pharmacological, biochemical and radioligand-binding studies have lead to the description of three different α, -receptor subtypes with a high affinity for prazosin, namely α_1A- (α_la-), α,_B- ( _lb-) and α_1D- (α,_d-) subtypes, with lower case subscripts being used for recombinant receptors and upper case subscripts for receptors in native tissues (Hieble P. et al., 1995, Pharmacol. Rev., 47, 267-270). In functional studies, α, receptors with a low affinity for prazosin have also been identified and termed α_1L receptors (Flavahan et al., 1986, Trends Pharmacol. Sci. 7, 347-349; Muramatsu et al., 1995, Pharmacol. Comm. 6, 23-28).

Several studies have demonstrated the presence of these α,-adrenoceptor subtypes in lower-urinary-tract tissues, as described in Andersson K. E., «4^tn International Consultation in Benign Prostatic Hyperplasia (BPH)», Paris, July 2-5, 1997, pp. 601-609).

Several studies have shown that the human prostate receives innervation from both the sympathetic and parasympathetic nervous systems.

However, the adrenergic nerves are considered responsible for prostatic smooth-muscle tone by releasing noradrenaline, thus stimulating contraction- mediating ,-adrenergic receptors. Approximately 50% of the total urethral pressure in BPH patients may be due to α,-adrenoceptor-mediated muscle tone. Functional studies have indicated the presence of important adrenoceptor functions in prostatic adenomatous and capsular tissue. Clinical studies with the prototypical α,- adrenoceptor antagonist, prazosin, reinforced the key role of α,-adrenoceptors in the control of prostatic smooth-muscle tone. This was also confirmed in the laboratory by studies showing that, although both α,- and α₂-adrenergic receptors are present within the human prostate, the contractile properties are mediated primarily by α, -adrenergic receptors. Many clinical investigations have confirmed that α,-adrenoceptor blockade relieves lower-urinary-tract symptoms (LUTS), both of iπitative and obstructive type, in patients with BPH.

Separate subtypes of α,-adrenergic receptors, a group (α_1H) with a high and a group (α_]L) with low affinity for prazosin, have been suggested to be present in the human prostate. All three high-affinity α,-adrenoceptor subtypes found in molecular cloning studies have been identified in prostatic stromal tissue. The α_la subtype was found to be dominant, representing about 60-85% of the a,-adrenoceptor population. Recent findings suggest that there may be quantitative differences in subtype populations between normal and hyperplastic prostates, the ratios between the subtypes α_la:α_lb:α_ld being 85:1 :14 in BPH tissue and 63:6:31 in non-BPH tissue.

The α_1A-adrenergic receptor was reported to mediate the contractile response of the human prostate in vitro. Ford A.P.D.W. et al, 1995, Br. J. Pharmacol. 114, 24 P, observed that the α_1A-adrenergic receptor may not mediate contractile responses to noradrenaline, and suggested the α_1L-adrenergic receptor as an candidate. Findings by Kenny B.A. et al., 1996, Br. J. Pharmacol. 118, 871-878, supported the view that the _1L-adrenergic receptor, which appears to share many of the characteristics of the α_1A-adrenergic receptor, mediates the contractile response of the human prostate.

On the other hand, it has also been suggested that the α_1A- and α,_L-adrenergic receptors may represent separate affinity states of the same receptor (Ford et al., 1997, Brit. J. Pharmacol. 121:1127-1135). Therefore, it is now confirmed that the α_la subtype is that which is important in mediating prostate smooth-muscle contraction.

The fact that the a,_a-adrenoceptor subtype predominates in prostate smooth muscle suggested a safer use of α_la-selective antagonists to treat LUTS secondary to BPH. However, a clinical trial performed with the selective antagonist of the α,_a-adrenergic receptor, Rec 15/2739, did not result in relief of LUTS, despite the presence of relaxing effects on prostate smooth muscle (Hieble et al., 1996, Pharmacol. Res. 33:145-160). Thus, this important finding indicated that relieving obstructive conditions is not sufficient to significantly relieve LUTS.

LUTS also develop in women of a certain age. As in men, LUTS in women includes both filling symptoms such as urgency, incontinence and nocturia, and voiding symptoms such as weak stream, hesitancy, incomplete bladder emptying and abdominal straining. The presence of this conditions both in man and women suggests that at least part of the aetiology may be similar in the two sexes.

In a recent study, an α, antagonist was reported to reduce LUTS in women more effectively than an anticholinergic (Serels S. et al., 1998, Neurourol. Urodynamics 17: 31-36). These authors suggested a role for α, antagonists in treating LUTS in women. The possible causes of the conditions which can explain these results are: a) dysfunction of the urethra and bladder neck, causing functional BNO (analogous to BPH-induced BNO), causing detrusor overactivity; and b) increased α,- adrenoreceptor activity in the detrusor, causing frequency and urgency. On these bases, α, antagonists are used in clinical practice to treat LUTS in women too.

The results of Serels also indicated that the combined administration of α, antagonists and anticholinergics can have improved efficacy in the treatment of LUTS, as also suggested by Fitzpatrick (Int. Brit. J. Urol. 85, Supp. 2: 1-5, 2000).

The finding that non-selective α, antagonists are useful in treating LUTS of both prostatic and non-prostatic origin in both males and females shows the usefulness of these molecules in treating LUTS of both obstructive and non- obstructive origins in males as well as females.

These results suggested that LUTS involves more organs than simply the prostate and justified further studies to search for , -adrenergic receptors in non- prostatic tissue.

mRNA for the α, receptor was found in the female urethra, with autoradiography confirming the predominance of the α_1A subtype (Andersson K.E.,

2000, Int. Brit. J. Urol. 85, Supp. 2: 12-18). The α,_A subtype also predominated in prostate and bladder trigone and was shown to be essential in mediating contraction in these tissues (Price et al., 1993, J. Urol. 150:546-551 ; Chappie, 1998, Eur. Urol., 34 (Suppl. 1):10-17; Foπey et al., 1994, Mol. Pharmacol. 45:703-708; Lepor et al., 1994, J. Pharmacol. Expt. Ther. 270:722-727). Both la and Id subtypes were found in the human detrusor, with the α_Id predominant (Malloy et al., 1998, J. Urol. 160: 937-943).

International application PCT US99/09846 (published as WO 99/57131) of Schwinn discloses the use of α_ld-selective antagonists in the treatment of LUTS without the side effects of non-selective α, antagonists. Selectivity is therein defined as at least two-fold selectivity for _ld relative to α_la or α_lb. Schwinn also discloses the use of antagonists that bind selectivity to both cc_la and _ld subtypes relative to the _lb subtype. However, no guidance was provided as to the relative affinity for α_la versus α,_d suptypes. Nor was any guidance provided on how to prepare or use compounds that are selective for α,_a and ,_d subtypes relative to the α_lb subtype.

Abrams et al. (1995, Br. J. Urol., 76:325-336) disclosed the use of tamsulosin to treat patients with BPH. The same author ascribed the efficacy of tamsulosin in treating LUTS to this molecule's capacity to interact with α_la- adrenergic receptors. There is thus a need for methods of treating LUTS without the side effects of non-selective a,-adrenergic antagonists. In particular, there remains a need for identifying selective antagonists of α,-adrenocepor subtypes.

We have tested α, antagonists for selectivity for α_la, α_lb and α_ld subtypes. Furthermore, using an animal model that reflects BNO effects in humans to test the effects of selective and non-selective α, antagonists on bladder function, we have found that antagonists that are selective for α,_a and α_ld subtypes relative to the α,_b subtype are more effective inhibitors of unstable-bladder contractions, compared to antagonists that are selective for a single subtype.

On these basis, antagonists that are selective for the combination of α_]a and α,_d subtypes relative to the α,_b subtype can be an effective means to treat lower-urinary- tract disorders.

Another possible use of α, antagonists is the treatment of neurogenic lower- urinary-tract dysfunction (NLUTD) caused by neurological disease or trauma. NLUTD may lead to debilitating symptoms and serious complications, including increased urinary frequency, incontinence, micturition difficulty, recuπent upper- urinary-tract infections and upper-urinary-tract deterioration. Management of NLUTD is indicated to preserve renal function and avoid urological complications. Administration of α, antagonists may benefit patients with NLUTD by facilitating bladder filling by alleviating high detrusor pressure during bladder filling, which is evidenced by poor bladder compliance and detrusor hypeπeflexia. In both animal models and patients with spinal-cord injury resistant to anticholinergics, α, antagonists improved bladder compliance. (Serels, ibid.; Fitzpatrick, ibid.; Kakizaki M. et al., 2000, Brit. J. Urol 85 (Supp. 2): 25-30; Sundin T. et al., 1977, Invest. Urol. 14: 322-328; McGuire et al., 1985, Neurourol. Urod. 4: 139-142; Swierzewski S.J. et al., 1994, J. Urol. 151 : 951-954).

SUMMARY OF THE INVENTION

The invention discloses compounds of general formula I:

where R is an aryl, cycloalkyl or polyhaloalkyl group,

R, is an alkyl, alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethanesulphonyloxy group; each of R₂ and R₃ independently represents a hydrogen atom or a halogen, or an alkoxy or polyfluoroalkoxy group, and n is 0, 1 or 2.

Without limitations, the prefeπed meaning of the aryl group is phenyl, that of cycloalkyl is cyclohexyl, of polyhalogenated alkyl is trifluoromethyl, of the alkyl group is lower alkyl, of the alkoxy group is lower alkoxy, in particular methoxy. A polyfluoroalkoxy group may be a trifluoromethoxy or 2,2,2-trifluoroethoxy group. The prefeπed value for n is 1.

The invention also includes the N-oxides and pharmaceutically-acceptable salts of these compounds. The invention further provides pharmaceutical compositions comprising a compound of general formula I or a N-oxide or pharmaceutically-acceptable salt of such a compound in admixture with a pharmaceutically-acceptable diluent or caπier.

In another aspect the invention provides compounds of general formula II:

where:

R₄ represents an alkyl, alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethanesulphonyloxy group; each of R₅ and R_<j independently represents a hydrogen or halogen atom or a polyfluoroalkoxy or alkoxy group; R₇ represents one or more substituents being a hydrogen or halogen atom or an alkyl, alkoxy, nitro, amino, acylamino, cyano, alkoxycarbonyl or carboxamido group;

R₈ represents a hydrogen atom or an alkyl group or an arylalkyl group; and n is 0, 1 or 2. The invention also includes the Ν-oxides and pharmaceutically-acceptable salts of these compounds.

Prefeπed alkyl groups which R₄ and R₈ may represent are lower alkyl groups, preferably the methyl group. Prefeπed alkoxy groups which R₄, R₅, R₆ and R₇ may represent are lower alkoxy groups, preferably the methoxy group. Prefeπed polyfluoroalkoxy groups which R₄, R₅ and R^ may represent are trifluoromethoxy or 2,2,2-trifluoroethoxy groups. The prefeπed value for n is 1.

In yet another aspect the invention includes compounds of general formula III:

where: Rg represents a phenyl, alkoxycarbonyl, alkylcarbonyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl, cyano or alkoxycarbonylamino group;

Rio represents an alkyl, alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethane- sulphonyloxy group; each of R_π and R₁₂ independently represents a hydrogen or halogen atom or a polyfluoroalkyl, polyfluoroalkoxy, cyano or carbamoyl group; and n is 0, 1 or 2; with the proviso that, if R, represents a phenyl group and both R_M and R₁₂ represent hydrogen and/or halogen atoms, then R₁₀ represents a polyfluoroalkoxy or trifiuoromethanesulphonyloxy group. The invention also includes the N-oxides and pharmaceutically-acceptable salts of these compounds.

When Re, does not represent a phenyl group, each of R_n and R,₂ preferably independently represents a hydrogen or halogen atom or a polyfluoroalkoxy group.

Alkyl and alkoxy groups preferably have from 1 to 4 carbon atoms; complex groups such as alkoxycarbonyl, alkylcarbonyl, alkylcarbamoyl, dialkylcarbamoyl, polyfluoroalkyl, polyfluoroalkoxy and alkoxycarbonylamino, are preferably construed accordingly. Prefeπed polyfluoroalkoxy groups are trifluoromethoxy and

2,2,2-trifluoroethoxy. The prefeπed value for n is 1. The invention further provides pharmaceutical compositions comprising a compound of general formulas I, II or III, or a N-oxide or pharmaceutically-acceptable salt of such a compound in admixture with a pharmaceutically-acceptable diluent or carrier. In another aspect, the invention is directed to methods for preventing contractions (including noradrenaline-mediated contractions) of the urethra, bladder and other organs of the lower urinary tract without substantially affecting blood pressure, by administering a compound that binds selectively to α,_a- and α_ld- adrenergic receptors and has a structure as given by general formulas I, II or III to a mammal (including a human) in need of such treatment in an amount effective for the particular use.

In yet another aspect, the invention is directed to methods for blocking α, receptors by delivery to the environment of said receptors, e.g. to an extracellular medium (or by administering to a mammal possessing said receptors), of an effective amount of a compound of the invention, in this way relieving diseases associated to overactivity of said receptors.

Another aspect of the invention is the use antagonists of α,_a- and α_ld- adrenergic receptors for lowering intraocular pressure, inhibiting cholesterol biosynthesis, treating cardiac aπhythmia and sexual dysfunction, and relieving pain of a sympathetic origin.

It is understood that «of a sympathetic origin» is defined as any physiological sensation, condition or response that depends upon any component of the sympathetic nervous system, can be modulated by the action of any component of the sympathetic nervous system, or can be affected by treatment of any component of the sympathetic nervous system.

A further object of the present invention is the release of selective antagonists of the α_la- and αι_d-adrenergic receptors of the present invention or pharmaceutical forms containing them in the environment of α, -adrenergic receptors wherein said release is effected by administering compounds of the present invention or pharmaceutical forms containing them to a mammal, including a human, possessing said receptors. A further object of the present invention is a method of treatment of a patient suffering from BPH, the method comprising administering an effective amount of a selective α,-adrenergic antagonist of the present invention or a pharmaceutical form containing it to a patient in need of such treatment. A further object of the present invention is a method for the treatment of lower-urinary-tract symptoms (LUTS), which include, but are not limited to, filling symptoms, urgency, incontinence and nocturia, as well as voiding problems such as weak stream, hesitancy, intermittency, incomplete bladder emptying and abdominal straining, the method comprising administering an effective amount of a selective α,- adrenergic antagonist of the present invention or a pharmaceutical form containing it to a patient in need of such treatment, and further comprising the possibility of concuπently administering an anticholinergic compound which may be selected from a group consisting of tolterodine, oxybutinin, darifenacin, alvameline and temiverine.

A further object of the present invention is a method for the treatment of neurogenic lower-urinary-tract dysfunction (NLUTD), the method comprising administering an effective amount of a selective α, -adrenergic antagonist of the present invention or a pharmaceutical form containing it to a patient in need of such treatment, and further comprising the possibility of concuπently administering an anticholinergic compound which may be selected from a group consisting of tolterodine, oxybutinin, darifenacin, alvameline and temiverine.

A further object of the present invention is a method for the treatment of LUTS in female patients, which includes, but is not limited to, filling symptoms, urgency, incontinence and nocturia as well as voiding problems such as weak stream, hesitancy, intermittence, incomplete bladder emptying, and abdominal straining, the method comprising administering an effective amount of a selective , -adrenergic antagonist of the present invention or a pharmaceutical form containing it to a woman in need of such treatment, and further comprising the possibility of contemporarily administering an anticholinergic compound which may be selected from a group consisting of tolterodine, oxybutinin, darifenacin, alvameline and temiverine Other features and advantages of the present invention will be apparent to those skilled in the art from the following detailed description and claims. DETAILED DESCRIPTION OF THE INVENTION:

All patents, patent applications and references cited herein are hereby incorporated by reference in their entirety. It is further understood that all compounds described and listed herein are meant to include all hydrates, solvates, polymorphs and pharmaceutically-acceptable salts thereof.

Some of the compounds described herein contain one or more asymmetric centres and may thus give rise to diastereomers and optical isomers. The present invention is meant to comprehend such possible diastereomers as well as their racemic and resolved enantiomerically-pure forms and pharmaceutically-acceptable salts thereof.

Some of the compounds described herein contain olefinic double bonds and, unless specified otherwise, are meant to include both E and Z geometric isomers. The invention provides methods for treatment of lower-urinary-tract symptoms

(LUTS), particularly those involving micturition, such as dysuria, incontinence and enuresis. Said methods involve administering to. patients selective antagonists of the α_la and α_ld subtypes of adrenergic receptors, relative to the α_lb subtype of adrenergic receptor, for a sufficient time and in an amount effective for relieving or ameliorating at least one symptom of the micturition disorders. Such symptoms include, but are not limited to, filling symptoms, urgency, incontinence and nocturia, as well as voiding problems such as weak stream, hesitancy, intermittence, incomplete bladder emptying and abdominal straining.

The term «treatment» is defined as the prevention, disappearance or amelioration of at least one of the foregoing LUTS.

« Obstructive symptoms» typically include hesitancy, poor stream, prolonged urination and feelings of incomplete emptying.

«Iπitative symptoms» typically include frequency, urgency, nocturia and unstable-bladder contractions. The present invention applies to the treatment of both obstructive and iπitative symptoms of the lower urinary tract. Prefeπed is the treatment of iπitative symptoms due to bladder-neck obstruction that may be secondary to obstructive disorders such as, for example, BPH. Efficacy of treatment may be determined by any known method. Such methods include determining urination volumes, frequency of urination, and frequency and strength of bladder contractions in individuals with neuromuscular dysfunction of the lower urinary tract; or interviewing such individuals to determine if they have experienced the amelioration of each of these symptom. Other measures of efficacy include a measurable reduction, preferably a clinically relevant reduction, of urine leakage related to feelings of urgency, urine leakage related to physical activity, coughing or sneezing, leakage of small amounts of urine, difficulty in bladder, urine leakage not related to urgency or activity, nocturia, a feeling of incomplete bladder emptying, etc.. The use of questionnaires and scales to measure symptom severity is widely accepted, complementing objective clinical measures and having the advantage of being inexpensive and potentially self-administered.

Female and male lower-urinary-tract questionnaires are available which provide a method of measuring symptom severity and life quality in a reproducible and valid fashion and allow an exact description of specific lower-urinary-tract symptoms.

The sums of scores collected for the questions included in the questionnaires are highly coπelated with patients' ratings of the magnitude of their urinary problems, and are very sensitive to changes induced by pharmacological treatment (Jackson et al., 1996, Brit. J. Urol., 77:805-812).

The adrenergic antagonistic activity of the compounds of the invention renders them useful as agents acting on body tissues particularly rich in α, -adrenergic receptors (such as prostate, urethra and bladder). Accordingly, the selective adrenergic antagonists within the invention, established as such on the basis of their receptor- activity profile, can be useful therapeutic agents, for example, for micturition problems associated with obstructive disorders of the lower urinary tract, including, but not limited to, BPH.

The α,-adrenergic antagonist drugs cuπently used for the symptomatic therapy of BPH are poorly selective for α, -adrenergic subtypes and thus subject to cause relevant side effects due to their action on the cardiovascular system.

The α_la- and α_ld-selective antagonists suitable for use in practising the present invention include, without limitations, those compounds having one or more of the following properties:

(1) Significant affinity for the _la and a_u subtypes of a,-adrenergic receptors: useful compounds preferably bind to the α,_a and α,_d subtypes of α, -adrenergic receptors with an affinity of between 100 and 0.1 nM. Without limitations, as described in detail below, affinity may be measured by determining the Ki of molecules in vivo or in vitro in cell extracts or fractions of extracts. Kis can be determined using, for examples, native or recombinant α, -adrenergic receptors and receptors that have been expressed in native or non-native species and/or cell types.

(2) Selectivity: compounds of the invention exhibit at least 10-fold affinity for α_la receptors relative to α_lb receptors, and at least 6-fold affinity for α,_d receptors relative to α,_b receptors. The compounds of the invention bind to the α_la and α_ld receptors with affinities that differ by less than 10-fold from each other.

Compounds belonging to the above defined general class are thus suitable candidates for screening to identify compounds useful in treating lower-urinary-tract symptoms and are exemplified, without limitations, by:

Compound A: N- { 3 - [4-(2-methoxypheny 1)- 1 -piperazinyl]propyl } -7-keto-5 - trifluoromethyl-7H-thieno[3,2-b]pyran-3-carboxamide;

Compound B: Ν-{3-[4-(5-chloro-2-methoxyphenyl)-l-piperazinyl]propyl}-5- methyl-3-phenylisoxazole-4-carboxamide;

Compound C: N-{3-[4-[5-fluoro-2-(2,2,2-trifluoroethoxy)phenyl]-l- piperazinyl]propyl}-3-phenyl-5-methylisoxazolyl-4-carboxamide; Compound D: 3-(2-chlorophenyl)-5-methyl-N-{3-[4-[2-(2,2,2- trifluoroethoxy)phenyl]- 1 -piperazinyljpropyl } isoxazole-4- carboxamide;

Compound E: N-{3-[4-[5-fluoro-2-(2,2,2-trifluoroethoxy)phenyl]-l- piperazinyl]propyl}-3- methyl-4-keto-2-phenyl-4H-l-benzopyran-8- carboxamide.

Syntheses of compound A and related compounds of formula I are described in U.S. Patent Application Ser. No. 09/627,766. The general methods of synthesis are described below.

Scheme 1

Direct condensation of 7-keto-7H-thieno[3,2-b]pyran-3-carboxylic acids of formula I with the ω-aminoalkylamino derivatives 2 (Scheme 1) leads to the compounds of the invention. The condensation can be caπied out in the presence of a condensing agent (e.g. dicyclohexylcarbodiimide or diethyl cyanophosphonate) optionally in the presence of a promoting agent (e.g. N-hydroxysuccinimide, 4- dimethylaminopyridine or NN'-carbonyldiimidazole) in an aprotic or chlorinated solvent (e.g. NN-dimethyl-formamide or chloroform) at -10/140°C (Albertson, 1962, Org. React. 12, 205-218; Doherty et al., 1992, J. Med. Chem. 35, 2-14; Ishihara, 1991, Chem. Pharm. Bull. 39, 3236-3243). In some cases the activated ester or amide intermediates (such as N-hydroxysuccinimide esters or acyl imidazolides) can be isolated and further reacted with 2 to be transformed into the coπesponding amides (I) in an aprotic or chlorinated solvent at 10/100°C.

Another activated intermediate which can be used is the mixed anhydride of 1, obtainable reacting 1 with an alkyl chloroformate in the presence of a tertiary amine

(e.g. triethylamine or N-methylmorpholine), which is reacted with 2 at 0-80°C.

Optionally a promoting agent (e.g. 1-hydroxypiperidine) may be added before the amine addition (Albertson, 1962, Org. React. 12, 157).

Alternatively the condensation can be caπied out without a solvent at 150- 220°C (Mitchell et al., 1931, J. Am. Chem. Soc. 53, 1879) or in high-boiling ethereal solvents (e.g. diglyme).

The condensation can also be performed through preparation and optional isolation of reactive derivatives of 1 such as acyl halides. Preparation and use of these derivatives are well documented in the literature and known to people skilled in the art.

Also less reactive derivatives of 1 can be used, such as alkyl esters, which in turn can be converted into I in the presence of a condensing agent (e.g. trimethylaluminum) in an aprotic and/or chlorinated solvent (e.g. hexane, dichloromethane) at -10/80°C, or without solvents at 80-180°C (S. M. Weinreb et al, 1977, Tetrahedron Lett. 4171; M. F. Lipton et al, 1979, Org. Synth. 59, 49).

By the same methods of condensation reported above and using H₂ΝCH₂(CH₂)_nCH₂X (with X = halogen or OH) as a reagent, 1 can be transformed into 3. In the case of X = OH, the alcoholic group is then converted into a suitable leaving group by methods well known to those skilled in the art. Compounds 3 (with X = halogen or an alkyl/arylsulphonyloxy group) can be subsequently reacted with a phenylpiperazine 8. The nucleophilic substitution is caπied out preferably, but not necessarily, at a temperature within the range of 20-200°C in a polar solvent such as dimethylformamide, acetonitrile, methanol or others, or without any solvent, usually in the presence of a base such as potassium carbonate. See also Gibson's chapter in Patai, 1968: "The Chemistry of the Amino Group", p. 45 et seq., Wiley International Science, N.Y.. Preparation of compounds 2 is disclosed in the literature and is well known to those skilled in the art, and includes nucleophilic substitution of a phenylpiperazine 8 on a N-(ω-haloalkyl)phthalimide or a proper ω-haloalkylnitrile or haloalkylamide by the method illustrated above for the condensation of compounds 3 and 8, or by addition of an α,β-unsaturated alkylnitrile or alkylamide in a proper solvent (e.g. acetonitrile, NN-dimethylformamide, a chlorinated solvent or other aprotic polar solvent) at a temperature between 0°C and the reflux temperature of the solvent. Standard phthalimido-group deprotection or reduction of the amido or cyano group then provides compounds 2. These reactions can be performed by methods well known to those skilled in the art.

The acids 1 of the invention in which R represents a cycloalkyl or phenyl group can be synthesised (Scheme 2) starting from methyl 2-acetyl-3- hydroxythiophene-4-carboxylate (prepared as described in J. Chem. Soc. Perkin Trans I, 507 (1986)), which can be esterified with the proper alkanoyl or aroyl chloride by using methods well known to those skilled in the art. Alternative procedures include the same methods described above for the amidification of 1, which could also be applied in the esterification step to afford 4.

Scheme 2

Monobromination of the methylketo group of 4 can afford 5, which can then be reacted with triphenylphosphine by normal procedures (by reflux in acetonitrile, toluene, or other aprotic solvent) to give the phosphonium salt 6. A subsequent intramolecular ester- Wittig reaction applied to this substrate can yield the thieno[3,2- bjpyranes 7. Hydrolysis of the ester function of 7 by acid- or basic-catalysed procedures that are well known to those skilled in the art yields compounds 1. Well-known hydrolysis procedures include the use of sodium hydroxide in aqueous ethanol at 40-75°C, or lithium hydroxide in aqueous dimethylformamide, dioxane or tetrahydrofuran at 40-100°C.

Compounds 1 where R is a polyfluoroalkyl group can be prepared from 2-acetyl-3-hydroxythiophene-4-carboxylate following the cyclization procedure described by Riva et al., 1997, Synthesis, 195-201, by direct cyclization in the presence of polyfluoroalkanoyl anhydrides catalysed by l,8-diazabicycloundec-7-ene.

Compounds I where R, is a trifluoromethanesulphonyloxy group can be synthesised starting from compounds I where R, is a hydroxy group using known procedures which include the use of trifluoromethanesulphonic anhydride or N-phenyltrifluoromethanesulphonimide in aprotic solvents such as 1 ,2-dichloroethane or other chlorinated solvents or toluene, at a temperature in the range between 20°C and the reflux temperature of the solvent (Tetrahedron Letters, 4607 (1973)). The N-oxides of compounds I are synthesised by simple oxidation procedures known to those skilled in the art. The oxidation procedure described in P. Brougham, 1987, Synthesis, 1015-1017, allows differentiation of the two nitrogens of the piperazine ring and both the Ν-oxides and Ν,Ν' -dioxides to be obtained.

Preparation of phenylpiperazines 8, which are not yet known in the literature, is well documented in the experimental section and uses synthetic procedures well known to those skilled in the art, which comprise the synthesis of the proper aniline through standard reactions and subsequent cyclization with b/i^,-(2-chloroethylamine) to afford piperazine following the method of Prelog (Prelog et al., 1933, Collect. Czech. Chem. Comm. 5, 497-502) or its variations (Elworthy T. R., 1997, J. Med. Chem. 40, 2674-2687).

Syntheses of compounds B ,C and D and related compounds of formula II are described in U.S. Patent Application Ser. No. 09/691,778. The general synthetic methods are described below. Scheme 3

Direct condensation of compounds la, 3-arylisoxazole-4-carboxyl acids, with ω-aminoalkyl derivatives 2a (Scheme 3) leads to the compounds of the invention. The condensation can be caπied out in the presence of a condensing agent (e.g. dicyclohexylcarbodiimide or diethyl cyanophosphonate) optionally in the presence of a promoting agent (e.g. N-hydroxysuccinimide, 4-dimethylaminopyridine or NN'-carbonyldiimidazole) in an aprotic or chlorinated solvent (e.g. dimethylformamide or chloroform) at -10/140°C (Albertson Ν. F., 1962, Org. React. 12, 205-218; Doherty A. M. et al, 1992, J. Med. Chem. 35, 2-14; Ishihara Y. et al, 1991, Chem. Pharm. Bull. 39, 3236-3243). In some cases the activated ester or amide intermediates (such as O-(Ν-succinimidyl) esters or acyl imidazolides) can be isolated and further reacted with 2a to be transformed into the coπesponding amides (II) in an aprotic or chlorinated solvent at 10/100°C. Another activated intermediate which can be used is the mixed anhydride of la, obtainable by reacting la with an alkyl chloroformate in the presence of a tertiary amine (e.g. triethylamine or N-methylmorpholine), then reacted with 2a at 0-80°C. Optionally a promoting agent (e.g. 1 -hydroxypiperidine) may be added before the amine addition (Albertson N. F., 1962, Org. React. 12, 157). Alternatively, the condensation can be caπied out without any solvent at 150- 220°C (Mitchell J. A. et al, 1931, J Am. Chem. Soc. 53, 1879) or in high-boiling ethereal solvents (e.g. diglyme).

The condensation can be also performed through preparation and optional isolation of reactive derivatives of la, such as acyl halides. Preparation and use of these derivatives is well documented in the literature and known to people skilled in the art.

Also less reactive derivatives of la can be used, such as alkyl esters, which, in turn, can be converted into II in the presence of a condensing agent (e.g. trimethylaluminum) in an aprotic and/or chlorinated solvent (e.g. hexane, dichloromethane) at -10/80°C, or without any solvent at 80-180°C, (Weinreb S. N. et al., 1977, Tetrahedron Lett. 4171 ; Lipton M. F. et al., 1979, Org Synth. 59, 49).

By the same methods of condensation reported above and using H₂NCH₂(CH₂)_nCH₂X (with X = halogen or OH) as a reagent, la can be transformed into 3a. In the case of X = OH, the alcoholic group is then converted into a suitable leaving group by methods well known to those skilled in the art. Compounds 3a (with X = leaving group such as halogen or an aryl/alkylsulphonyloxy group) can be subsequently reacted with an appropriate phenylpiperazine 8a. The nucleophilic substitution is caπied out preferably, but not necessarily, at a temperature within the range of 20-200°C in a polar solvent such as N,N-dimethylformamide, acetonitrile or methanol, or without any solvent, usually in the presence of a base such as potassium carbonate. See also Gibson's chapter in Patai, 1968: "The Chemistry of the Amino Group", p. 45, Wiley Int. Sci., N.Y..

Scheme 4

1a

Preparation of compounds la (Scheme 4), which are not commercially available, is disclosed in detail in the literature and is well known to those skilled in the art and is usually caπied out performing 1,3-dipolar cycloaddition reactions on benzohydroxamoyl halides (usually prepared by halogenation of properly substituted benzaldoximes with alkaline halogens or hypohalides or N-chloro-(or bromo)succinimide) with β-ketoesters or alkyl β-aminoacrylates (R_s = H) or alkyl propiolates in alkaline conditions in a proper solvent (e.g. NN-dimethylformamide, ethanol, diethyl ether, chlorinated solvents at a temperature in the range between - 20°C and solvent reflux, usually caπying out the reactions at 20-30°C) (Scheme 4). Also see J. Chem. Soc. 1963, 5838-5845 and 5845-5854; J. Am. Chem. Soc. 1985, 107, 2721-2730, J. Agric. Food Chem. 1995, 43, 219-228; US 4,144,047.

Variations of the substitution at position R₈ can be obtained by using properly substituted β-ketoesters or alkyl propiolates or by reacting the lithium carbanion of the methyl derivatives la (R₈ = CH₃) with various electrophiles in aprotic solvents such as tetrahydrofuran, diethyl ether, benzene, toluene or others, at a temperature between -78°C and the reflux temperature of the solvent (J. Org. Chem. 1985, 50, 5660-5666; J. Med. Chem. 1988, 31, 473-476; J Med. Chem. 1990, 33, 2255-2259). The carboxylic functionality can be protected or not protected.

Compounds II where R₄ is a trifluoromethanesulphonyloxy group can be synthesised starting from compounds II where R₄ is a hydroxy group by known procedures that include the use of trifluoromethanesulphonic anhydride or N-phenyltrifluoromethanesulphonimide in aprotic solvents such as, for example, 1 ,2-dichloroethane or other chlorinated solvents, toluene, at a temperature in the range between -20°C and the reflux temperature of the solvent (Hendickson J. B. et al., 1973, Tetrahedron Letters 4607-4610).

The Ν-oxides of compounds II may be synthesised by simple oxidation procedures known to those skilled in the art. The oxidation procedure described by Brougham P., 1987, Synthesis, 1015-1017, allows differentiation of the two nitrogen atoms of the piperazine ring, and both the Ν-oxides and Ν,Ν'-dioxide to be obtained. Synthesis of compound E and related compounds of formula III is disclosed in

U.S. Patent Application Ser. No. 09/691,770. The general synthetic methods are described below.

Condensation of acids lb with ω-aminoalkylamino derivatives 2b (Scheme 5) can be caπied out in the presence or absence of a condensing agent (e.g.

Scheme 5

dicyclohexylcarbodumide or diethyl cyanophosphonate) optionally in the presence of a promoting agent (e.g. N-hydroxysuccinimide, 4-dimethylaminopyridine or N,N'-carbonyldiimidazole) in a dipolar aprotic or chlorinated solvent (e.g. N,N-dimethylformamide or chloroform) at -10/140°C (Albertson N. F., 1962, Org. React. Y2, 205-218; Doherty A. M. et al., 1992, J Med. Chem. 35, 2-14; Ishihara Y. et al., 1991, Chem. Pharm. Bull. 39, 3236-3243).

In some cases the intermediate esters or amides (such as N- hydroxysuccinimide esters or acyl imidazolides) can be isolated and further reacted with 2b to be transformed into the coπesponding amides (III) in a polar aprotic or chlorinated solvent at 10/100°C. Another intermediate which can be used is the mixed anhydride obtainable by reacting lb with an alkyl chloroformate in the presence of a tertiary amine (e.g. triethylamine or N-methylmorpholine) followed by addition of 2b at 0-80°C. Optionally a promoting agent (e.g. 1-hydroxypiperidine) may be added before the amine addition (Albertson N. F., 1962, Org. React. Y2, 157). Alternatively, the condensation can be caπied out without any solvent at 150-

220°C (Mitchell J. A. et al., 1931, J Am. Chem. Soc. 53, 1879) or in high-boiling ethereal solvents (e.g. diglyme). The condensation can also be performed through isolation of reactive derivatives of lb such as acyl halides. Preparation and use of these derivatives is well documented in the literature and clearly known to people skilled in the art.

Also less reactive derivatives of lb can be used, such as alkyl esters, which, in turn, can be converted into III in the presence of a . condensing agent (e.g. trimethylaluminium) in an aprotic and/or chlorinated solvent (e.g. hexane, dichloromethane) at -10/80°C, or without any solvent at 80-180°C (Weinreb S. M. et al., 1977, Tetrahedron Lett. 4171; Lipton M. F. et al., 1979, Org. Synth. 59, 49).

By the same methods of condensation reported above, using H₂NCH₂(CH₂)_nCH₂X (with X = halogen or OH) as a reagent, derivatives lb can be converted into the coπesponding derivatives 3b. Compounds 3b ( with X = halogen or a leaving group) can be subsequently reacted with the appropriate phenylpiperazine 8b directly or by two sequential reactions, in the case of OH derivatives, which include conversion of the alcoholic group into a suitable leaving group by methods well known to those skilled in the art. The nucleophilic substitution on 3b to give III is preferably, but not necessarily, caπied out at a temperature within the range of 20- 160°C in a polar solvent such as N,N-dimethylformamide, acetonitrile, methanol or other, or without any solvent, in the presence of a base such as potassium carbonate. See also Gibson's chapter in Patai, 1968, 77ze Chemistry of the Amino Group, p. 45,

(R₉ = COAIk)

Wiley Int. Sci., N.Y..

Compounds lb of the invention in which R, represents an alkylcarbonyl group (Scheme 6) can be synthesised starting from 2-hydroxy-3-(l-propenyl)propiophenone which is condensed with excess diethyl oxalate in the presence of a base (e.g. sodium ethoxide, sodium hydride, sodium metal, lithium or sodium amide, potassium t-butoxide, lithium hexamethyldisilyl azide) in a suitable solvent such as ethanol, toluene, dioxane, tetrahydrofuran, 1 ,2-dichlorobenzene (or other aprotic solvent) or without any solvent at a temperature in the range between 20°C and the reflux temperature of the reaction mixture (March J., 1992, Advanced Organic Chemistry, J. Wiley, Part 2, Chapter 10, 0-108, 491-493,; Schmutz, J., 1951, Helvetica Chimica Acta, 767-779). The intermediate crude α,γ-diketoester is directly cyclized to give 9 (Alk = C,.₄ alkyl), with no purification, by acid catalysis (e.g. 37% HCl, 98% H₂SO₄, glacial acetic acid or trifluoroacetic acid, perchloric acid) in an appropriate solvent such as ethanol, toluene, a chlorinated solvent, or without any solvent, at a temperature in the range between 20°C and the reflux temperature of the reaction mixture (Bryan J. D., 1960, J Chem. Soc. Perkin Trans. 1, 1279-1281). Hydrolysis of the ester function of 9 by acid or base catalysis known to those skilled in the art, affords Compounds 10. Well-known procedures include the use of sodium hydroxide in aqueous ethanol at 40-75 °C or lithium hydroxide in aqueous dimethylformamide, dioxane or tetrahydrofuran at 40-100°C.

Compounds 10 can be converted into keto derivatives 11 by direct reaction of lithium carboxylate with alkyl lithium derivatives (Rubottom G. M. et al., 1983, J. Org. Chem. 48, 1550-1552). Alternatively, by conversion of the carboxy group into a more reactive C(O)X group, where X is 1 -imidazolyl, chloro or bromo, OC(O)R or other reactive group, and then continuing the reaction with, for example, Meldrum's acid to afford an enolacyl derivative that can be hydrolysed with acetic acid to give 11 or, alternatively, with the magnesium salt of a suitable β-diester (such as di-t-butyl malonate or ethyl malonate or diethyl malonate) to afford the coπesponding β- ketoester to be hydrolysed to 11.

Subsequent oxidative cleavage of the exocyclic double bond by permanganate oxidation (or other oxidative method well known to those skilled in the art; see, for example, Haines A. H., 1985, Methods for the oxidation of organic compounds,

Academic press, Chapter 3, part 5, 146-151) yields the desired carboxylic acids lb, with R, = COAlk.

Acids lb in which R, is a COOAlk group can be clearly prepared from intermediates 9 caπying out the double-bond oxidation step as described above for 11. Acids lb in which R, is a CONR,R₂ group can be prepared from intermediates

10 through an amidification reaction, which is well known to those skilled in the art, such as that described for lb, with ammonia or an appropriate amine, then caπying out the double-bond oxidation step as described above. Due to the mild conditions (EP 625522, Sohda T. et al.), a prefeπed method of amidification includes conversion of 10 to the respective acyl chloride by the use of oxalyl chloride. Compounds III in which R, is a cyano group can be obtained from compounds III with R, = CONH₂ by a dehydration reaction through the use of triphenylphosphine in carbon tetrachloride or toluene or other suitable solvent at room-reflux temperature or, preferably, by the use of phosphorous-oxychloride/dimethylformamide or by other dehydration methods known to those skilled in the art (March J., 1962, Advanced Organic Chemistry, J. Wiley, Part 2, Chapter 7, part 39, 1041-1042).

Compounds HI in which R, is a NHCOOAlk group can be prepared from intermediates 10 by Curtius reaπangement (March, 1992, Advanced Organic Chemistry, 4"¹ edition, J. Wiley ed., pages 1991-1992) caπied out with diphenylphosphoryl azide and triethylamine in an appropriate alkanol at reflux or in a mixture of acetonitrile (or other solvent) and the appropriate alkanol. Oxidation of these intermediates as above affords acids lb with R, = NHCOOAlk.

Compounds III in which R,₀ is a trifluoromethanesulphonyloxy group can be synthesised starting from compounds III in which R_|0 is a hydroxy group by well- known procedures that include the use of trifluoromethanesulphonic anhydride or N-phenyltrifluoromethanesulphonimide in aprotic solvents such as 1 ,2-dichloroethane or other chlorinated solvents or toluene at a temperature in the range between -20°C and the reflux temperature of the solvent (Hendickson J. B., 1973, Tetrahedron letters, 4607-4610). The N-oxides of compounds III can be synthesised by simple oxidation procedures well known to those skilled in the art. The oxidation procedure described by P. Brougham et al., Synthesis, 1987, 1015-1017, allows the two nitrogens of the piperazine ring to be differentiated, allowing both the N-oxides and N,N'-dioxide to be obtained.

The compounds belonging to the class of α, -receptor antagonists are well known. Screening generic α, antagonists to identify the candidates that are useful in practising the present invention involves:

1) evaluating their affinity and selectivity in binding α_la, α,_b and α_ld subtypes of the α, -adrenergic receptor; and 2) confirming their pharmacological activity using one or more animal models of lower-urinary-tract dysfunction. Affinity of the compounds of the invention for each subtype of the α, receptor can be assessed by receptor binding assays using, for example, the specific ligand ³H-prazosin according to Testa R. et al., 1995, Pharmacol. Comm. 6, 79-86.

Other assays that may be used to measure molecule affinity for α, -receptor subtypes are also encompassed by the present invention.

The binding affinity of a molecule can be measured for different subtypes of the , -adrenergic receptor, and the concentration at which a molecule inhibits binding of a control compound (e.g. prazosin) to a given receptor can be calculated using a regression equation or equivalent computational methods that are well-known (Tallarida et al., 1981, Manual of Pharmacologic Calculations. Springer- Verlag, pp. 10-12). These results are usually expressed as Ki. The results from these assays are used to calculate a measure of receptor selectivity, expressed as the ratio of affinities (Ki) for a given pair of receptors.

As discussed above, the compounds of the present invention bind selectively to α_la and α_ld receptors relative to the α_lb receptor. It will be understood that measurements of the affinity of a particular molecule may vary depending upon the source of the receptor, as well as specific assay conditions.

A compound is considered to be «selective» for α,_a and α,_d receptors relative to the α,_b receptor if it exhibits a selectivity ratio of at least 10-fold for α,_a versus α_lb (i.e. the Ki for α,_a subtype is at least 10-fold below the Ki for α_lb subtype) and at least

6-fold for α_ld receptor versus α,_b (i.e. the Ki for _ld subtype is at least 6-fold below the

^■ Ki for α_lb subtype). Additionally, the selectivity ratio of α_la and α,_d receptors should be lower than 10.

When a compound is found to be selective for _la and α_ld subtypes versus α_lb subtype, its pharmacological activity can be confirmed using one or more animal model systems for dysfunction of the lower urinary tract.

A useful animal model system for measuring such pharmacological activity is, without limitations, cystometry in conscious rats with partial bladder-neck obstruction. This model measures detrusor contractions during bladder filling which do not cause urine expulsion (unstable-bladder contractions). This model is reported in the literature as related to LUTS occuπing in patients having obstructive urethral syndromes (Michel, 2000, Drugs of Today, 386 (Supp. B2): 3-6)

THERAPEUTIC APPLICATIONS The ones below are guidelines for effective oral, parenteral and intravenous doses expressed as mg/kg of body weight daily, to be used in obstructive symptoms of the lower urinary tract: general 0.001 to 20 prefeπed 0.05 to 3 much prefeπed 0.5 to 2

The much prefeπed values refer to oral administration. Intravenous doses should be 10 to 100 times lower. Doses for selective use, i.e. doses which are active in the lower urinary tract with no substantial effect on blood pressure, depend upon the particular compound used. Usually, in the case of compounds which selectively inhibit urethral contraction, up to four times the ED₅₀ amount used to inhibit urethral contractions can be administered with no substantial effect on blood pressure. Further dose refinement and optimisation is possible simply using routine experiments. The active compounds of the invention can be administered orally, for example with an inert diluent or edible vehicle, or can be enclosed in gelatine capsules, or can be compressed into tablets. For oral therapeutic administration, the active compounds of the invention can be incorporated into excipients and used as tablets, troches, capsules, elixirs, suspensions, syrups, wafers, chewing gums and the like. These preparations should contain at least 0.5%o of active compound, but the amount of active ingredient may vary depending upon the particular form and can conveniently vary from 5%> to about 70%> of the weight of the unit. The amount of active ingredient in these compositions is such as to allow an exact dosage to be obtained even when the desired dosage can be obtained by administering a plurality of dosage forms. The prefeπed compositions and preparations of the invention are prepared in such a manner that an oral dosage unit contains 0.1 to 300 milligrams of active compound. Tablets, pills, capsules, troches and the like can further contain, for example, the following ingredients: a ligand such as microcrystalline. cellulose, tragacanth and gelatine; an excipient such as starch or lactose; a disintegrating agent such as alginic acid, sodium starch glycolate, maize starch and the like; a lubricant such as magnesium stearate and hydrogenated castor oil; a gliding agent such as colloidal silica; and a sweetener such as sucrose or saccharin or a flavour such as peppermint, methyl salicylate or orange flavour can be added. When the dosage unit form is a capsule, this can contain a fluid vehicle such as a fatty oil in addition to the above materials. Other dosage unit forms may contain various other materials which modify the physical form of the unit, e.g. coatings. Therefore, tablets and pills can be coated with sugar, shellac or other agents for enteric coating. A syrup may contain, in addition to active compounds, sucrose as a sweetener and certain preservatives, dyes and flavours. The materials used in the preparation of these various compositions should be pharmaceutically pure and nontoxic in the amounts used. For parenteral therapeutic administration, the active compounds of the invention can be incorporated into a solution or suspension. These preparations should contain at least 0.1 %> of active compound, but this may vary from 0.5 to about 30%> of the weight of the preparations. The amount of active compound in these compositions is such as to allow an exact dosage to be obtained. Preferred compositions and preparations according to the present invention are prepared so that a parenteral unit dosage contains 0.2 to 100 milligrams of active compound. Solutions and suspensions can also contain the following ingredients: a sterile diluent such as water for injection, saline, fixed oils, polyethylene glycol, glycerine, propylene glycol and other synthetic solvents; antibacterial agents such as benzyl alcohol and methylparabens, antioxidants such as ascorbic acid and sodium disulphite, kelating agents such as ethylenediaminotetraacetic acid; buffers such as acetates; citrates and phosphates and agents for controlling tonicity such as sodium chloride and dextrose. Bottles for multiple parenteral doses can be of glass or plastic material. Other compositions suitable for administration by diverse routes of administration and containing compounds according to the present invention are also within the scope of the invention. The dosage forms, further ingredients and routes of administration herein envisaged include those described in United States patents US 4,089,969 and US 5,091,182, all incorporated by reference in their entirety. EXAMPLE 1 (Compound A)

N-{3-[4-(2-Methoxyphenyl)-l-piperazinyl]propyl}-7-keto-5-trifluoromethyl-7H^r- thieno [3,2-b] pyran-3-carboxamide a) Methyl 7-keto-trifluorometyl-7H-thieno [3,2-b] pyran-3-carboxylate (Compound IA)

3.95 ml of trifluoroacetic anhydride and 9.2 ml of 1,8- diazabicyclo[5.4.0]undec-7-ene (DBU) were added at 0-5°C to a mixture of 4.10 g of methyl 2-acetyl-3-hydroxythiophene-4-carboxylate (prepared as described in J. Chem. Soc. Perkins Trans I, 1986, 507) and 14 ml of pyridine. The mixture was heated at 80°C for 27 hours. During this time three further additions of trifluoroacetic anhydride (9.9 ml in total) and DBU (9.2 ml) were made. After cooling to 20-25°C the mixture was poured into ice (250 g) and 37%> hydrochloric acid (50 ml) and extracted with ethyl acetate (2 x 80 ml). The combined organic layers were washed with water, dried over sodium sulphate and evaporated to dryness in vacuo. The residue was treated with petroleum ether-ethyl acetate 7:3 and filtered, and the filtrate purified by flash chromatography (petroleum ether-ethyl acetate, gradient from 7:3 to 0:1). The residue was dissolved in diethyl ether, washed with 5% aqueous sodium carbonate and then with water, dried over sodium sulphate and evaporated to dryness in vacuo to give the title compound (22%>), melting at 148-158°C, which can be used in the next step without any further purification. The test sample was obtained by crystallisation from ethanol. M.p. 163-163°C.

^!H-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

8.58 s 1H H2

6.80 s 1H H6

3.96 s 3H COOCH3

b) 7-keto-5-trifluoromethyI-7H-thieno[3,2-blpyran-3-carboxy lie acid (Compound IB)

A mixture of 0.70 g of compound IA, 5.6 ml of dioxane and 8.4 ml of 9N hydrochloric acid was refluxed for 75 minutes. After cooling to 20-25°C, the precipitated solid was filtered, washed with dioxane-water 1 :1.5 and then with water to give 0.46 g of the title compound as a grey solid, melting at 249-251°C.

^JH-NMR (200 MHz) Spectrum, Solvent: DMSO-dfr Chemical shift (δ)

13.50 sa 1H COOH

8.25 s 1H H2

7.19 s 1H H6

c) N-{3-f4-(2-Methoxyphenyl)-l-piperazinyl]propyI}-7-keto-5-trifluoromethyl- 7H-thieno[3,2-blpyran-3-carboxamide

0.56 ml of 93% diethyl cyanophosphonate and 0.48 ml of triethylamine were added at 0°C to a stiπed solution of 0.82 g of compound IB and 0.86 g of l-(3-aminopropyl)-4-(2-methoxyphenyl)piperazine (prepared as described in patent GB 2,161,807) in 16 ml of anhydrous NN-dimethylformamide. After 2 hours' stiπing at 20-25°C and 3 days' rest at the same temperature, the reaction mixture was poured into 150 ml of water and extracted with ethyl acetate. The organic layer was washed with water, dried over sodium sulphate and evaporated to dryness in vacuo. The crude was purified by flash chromatography (ethyl acetate-2.7Ν ammonia in methanol 95:5) to give the title compound as a light-brown solid, melting at 170-177°C (33%>).

ΪH-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

8.55 s 1H H2

7.10 t 1H NH

6.85-7.10 m 4H methoxyphenyl CHs

6.80 s 1H H6

3.88 s 3H OCH3

3.60 q 2H NHCHj

2.90-3.15 m 4H 2 piperazine CH2S

2.45-2.80 m 6H 2 piperazine CH2S, CH2CH2CH2N

1.88 dt 2H CH2CH2CH2 EXAMPLE 2 (Compound B)

N-{3-[4-(5-Chloro-2-methoxyphenyl)-l-piperazinyl]propyI}-5-methyl-3- phenylisoxazole-4-carboxamide a) l-(5-Chloro-2-methoxyphenyl)-4-[3-(N-phthalimido)propyI]piperazine (Compound 2A)

A mixture of 28.64 g of l-(5-chloro-2-methoxyphenyl)piperazine, 44.6 g of anhydrous potassium carbonate and 33.65 g of N-(3-bromopropyl)phthalimide in 250 ml of acetonitrile was stiπed at reflux for 8 hours. After cooling to room temperature, 800 ml of water was added under stiπing and the resulting suspension was filtered by suction yielding a yellowish solid, which was washed with 300 ml of water and crystallised from methanol affording 46.5 g (91%>) of the title compound, melting at 131-133°C.

^JH-NMR (200MHz) spectrum; Solvent: CDCI3; Chemical shift (δ)

7.78-7.82 m 2H phthalimide H3, H6 7 7..6644--77..7788 mm 2 2HH phthalimide H4, H 5

6.92 dd 1H methoxyphenyl H4

6.65-6. 78 m 2H methoxyphenyl H3 , H6

3.81 s 3H CH3O

3.71-3.89 m 2H CH₂N(CO)₂ 2 2..7788--33..0000 mm 4 4HH 2 piperazine CH2S

2.40-2.65 m 6H 2 piperazine CH2S, CHyCHyCHMCO)?_.

1.80-2.03 m 2H CH7CH7CH7

b) l-(3-Aminopropyl)-4-(5-chloro-2-methoxyphenyl)piperazine trihydrochloride • 2.15 H,O (Compound 2B) A solution of 20.7 g of Compound 2A and 8.6 ml of 85%> hydrazine hydrate in

300 ml of 95%) ethanol was stiπed at reflux for 3.5 hours. Afterwards, the reaction mixture was cooled to room temperature, diluted with 400 ml of water, acidified with 37%o hydrochloric acid (pH = 1) and stiπed for 0.5 hours. The precipitated solid was collected by filtration and washed with IN hydrochloric acid followed by water. The filtrate was concentrated by evaporation in vacuo, filtered, made basic by the addition of 35%o sodium hydroxide at 0-5°C and extracted with diethyl ether. The organic layer was washed with brine, dried over sodium sulphate and evaporated to dryness in vacuo affording 13.6 g (96%>) of the title compound as a base. Acidification of a solution of the base in chloroform with more than three equivalents of 3N ethanolic hydrochloric acid, followed by evaporation to dryness in vacuo and crystallisation of the residue from ethanol/diethyl ether 10:3, yielded the title compound, melting at 200-202°C.

H-NMR (200MHz) spectrum; Solvent: CDCI3; Chemical shift (δ)

11.20-11.50 sa 1H NH⁺ 8 8..1100--88..4400 ssaa 3 3HH NHj+

6.85-7.10 m 3H phenyl H3, 4, H6

5.10 sa 5.3H NH+, 2.15 H2O

3. 79 s 3H CH30

3.35-3.65 m ^' 4H 2 piperazine CH2S

33..0033--33..3355 mm 66HH 2 piperazine CH7S, CH?CH CH7NHι⁺

2.80-3.03 m 2H CH?CH?CH?NH?+

1.95-2.22 m 2H CH7CH7CH

c) Ν-{3-[4-(5-Chloro-2-methoxyphenyl)-l-piperazinyl]propyl}-5-methyl-3- phenylisoxazole-4-carboxamide 1.08 g of 93%o diethyl cyanophosphonate and 0.92 ml of triethylamine were added to a mixture of 1.22 g of 3-phenyl-5-methylisoxazole-4-carboxylic acid (Aldrich), 1.87 g of Compound 2B as its base and 30 ml of anhydrous dimethylformamide stiπed at 0-5°C. The temperature was allowed to rise to 20-25°C and, after 3.5 hours' stiπing, the mixture was poured into 300 ml of water and extracted with ethyl acetate. The combined organic layers were washed with 5%> aqueous sodium carbonate and then water. After drying over sodium sulphate, the solvent was removed in vacuo. The crude was crystallised from ethanol to yield 2.11 g (75%) of the title compound, melting at 139-142°C.

^ΪH-NMR (200MHz) spectrum; Solvent: CDCI3; Chemical shift (δ) 7.60-7.70 m 2H phenyl H2, H6 7.45-7.55 m 3H phenyl H3, H4, H5

6.95 dd 1H methoxyphenyl H4

6.85 d 1H methoxyphenyl H6

6.75 d 1H methoxyphenyl H3 6.25 t 1H NH

3.82 s 3H OCH3

3.40 q 2H NHCH7

2.80-2.95 m 4H 2 piperazine CH2S

2.69 s 3H CH3 2.40-2.55 m 4H 2 piperazine CH2S

2.30 t 2H CONHCH2CH2CH7N

1.55-1.70 m 2H CH2CH7CH2

EXAMPLE 3 (Compound C) N-{3-[4-[5-Fluoro-2-(2,2,2-trifluoroethoxy)phenyl]-l-piperazinyl]propyl}-5- methyl-3-phenylisoxazoIe-4-carboxamide a) 5-FIuoro-2-(2,2,2-trifluoroethoxy)nitrobenzene (Compound 3A)

A stiπed mixture of 3.14 g of 4-fluoro-2-nitrophenol, 13 g of cesium carbonate and 20 ml of anhydrous dimethylformamide was heated at 100°C for 4 hours. 6.65 g of 2,2,2-trifluoroethyl p-toluenesulphonate was then added and the mixture was stiπed at the same temperature for 40 hours. The solvent was then removed under reduced pressure at 35°C and 50 ml of water was added to the residue. The mixture was acidified with 37%> hydrochloric acid and extracted with 3 x 40 ml of ethyl acetate. The organic layer was washed with 20 ml of brine, dried over sodium sulphate and evaporated to dryness under reduced pressure. The residue was purified by flash chromatography (petroleum ether / ethyl acetate 100:7) to afford 1.53 g (32%>) of Compound 3 A as an oil.

^]H-NMR (200MHz) spectrum; Solvent: CDCI3; Chemical shift (δ)

7.65 dd 1H H6

7.32 ddd 1H H4 7.16 dd 1H H3

4.42 q 2H CH2

b) 5-Fluoro-2-(2,2,2-trifluoroethoxy)aniline (Compound 3B)

A mixture of 0.66 g of Compound 3A and 0.07 g of Raney-Nickel in 20 ml of ethyl acetate was stiπed for 14 hours at 20-25°C. The organic layer was separated and the mixture extracted with 2 x 40 ml of ethyl acetate. The combined organic layers were washed with 20 ml of brine, dried over sodium sulphate and evaporated to dryness in vacuo to afford 0.52 g (90.6%>) of Compound 3B as an oil.

^]H-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

6.70 dd 1H H6

6.28-6.50 m 2H H3 and H4 4.32 q 2H CH2

3.92 sa 2H NH2

c) l-[5-Fluoro-2-(2,2,2-trifluoroethoxy)phenyl]piperazine (Compound 3C)

A stirred mixture of 0.52 g of Compound 3B, 0.45 g of bis- (2-chloroethyl)amine hydrochloride, 0.5 g of potassium iodide, 0.34 g of anhydrous potassium carbonate and 20 ml of w-butanol was refluxed for 32 hours under nitrogen. The solvent was removed under reduced pressure. The residue was treated with 10 ml of water and then 10 ml of 20%> aqueous sodium carbonate and extracted with 2 x 30 ml of ethyl acetate. The organic layer was washed with, brine, dried over sodium sulphate and evaporated to dryness in vacuo. The residue was purified by flash chromatography (chloroform : 2N ammonia in methanol, gradient from 100:3 to 100:5) to afford 0.1 g (14%) of Compound 3C as an oil.

JH-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

6.80-6.93 m 1H H3

6.55-6. 71 m 2H H6, H4

4.36 1 2H CH2CF3

3.05 s 8H piperazine CH2

2.38 s . 1H . NH d) N-(3-Chloropropyl)-3-phenyl-5-methylisoxazole-4-carboxamide (Compound 3D)

4.48 ml of 93% diethyl cyanophosphonate and 7.66 ml of triethylamine were added at 0°C to a stiπed mixture of 5.05 g of 3-phenyl-5-methylisoxazole-4- carbossylic acid, 3.57 g of 3-chloropropylamine hydrochloride and 50 ml of dimethylformamide. The temperature was allowed to rise to 20-25°C and, after stiπing for 3.5 hours, the mixture was poured into 100 ml of ice-cold water, the precipitated solid was filtered and washed on a funnel with a 2:1 mixture of water: dimethylformamide followed by water. Drying afforded the title compound (89%). M.p. 122-124°C.

^JH-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

7.45-7.60 m 5H phenyl CHs

5.50 sa 1H NH

3.30-3.45 m 4H CH7CH7CH7

2. 70 s 3H CH3

1.80-1.90 m 2H CH7CH7CH7

e) N-{3-[4-[5-Fluoro-2-(2,2,2-trifluoroethoxy)phenyl]-l-piperazinyllpropyl}-5- methyl-3-phenylisoxazole-4-carboxamide

A mixture of 0.3 g of Compound 3D, 0.29 g of Compound 3C and 0.14 g of anhydrous potassium carbonate was stiπed at 160°C for 20 minutes. After cooling to room temperature, the crude was purified by flash chromatography

(dichloromethane/2N ammonia in methanol 97.5:2.5) to give the title compound

(59%). M.p. 123-125°C.

^]H-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

7.60-7.70 m 2H phenyl H2, H6

7.45-7.55 m 3H phenyl H3, H4, H5

6.80-6.90 m 1H trifluoroethoxyphenyl H3

6.55-6. 70 m 2H trifluoroethoxyphenyl H4, H6

6.20 t 1H NH

4.30 <7 2H OCH2CF3 3.35 q 2H NHCH7

2.80-2.95 m 4H 2 piperazine CH2S

2.65 s 3H CH₃

2.35-2.45 m 4H 2 piperazine CH2S 2.25 t 2H CONHCH2CH2CH7N

1.50-1.65 m 2H CH7CH7CH7

EXAMPLE 4 (Compound D)

3-(2-Chlorophenyl)-5-methyl-N-{3-[4-[2-(2,2,2-trifluoroethoxy)phenyl]-l- piperazinyI]propyl}isoxazole-4-carboxamide

a) l-[2-(2,2,2-Trifluoroethoxy)phenyl1-4-[3-(N-phthalimido)propyllpiperazine (Compound 4A)

The title compound was prepared as in Example 2 for Compound 2A, replacing l-[2-(2,2,2-trifluoroethoxy)phenyl]piperazine (prepared as described in patent EP 748800) for l-(5-chloro-2-methoxyphenyl)piperazine. The reaction mixture was extracted with diethyl ether, the organic layer was dried over sodium phosphate and then filtered on a silica gel panel washing with diethyl ether. Evaporation to dryness in vacuo afforded the title compound (91%), melting at 11 1-1 13°C.

^]H-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ) 7 7..6600--77..9922 mm 4 4HH phthalimide CHs

6.80-7.10 m 4H trifluoroethoxyphenyl CHs

4.35 q 2H OCH2CF3

3.80 t 2H (CO)₂NCH2

2.75-3.12 m 4H 2 piperazine CH2S 2 2..3300--22..7755 mm 6 6HH (CO) 2NCH2CH2CH2H, 2 piperazine CH2S

1. 75-2.10 m 2H CH2CH2CH2

b) l-(3-A,inopropyl)-4-[2-(2,2,2-trifluoroethoxy)phenyl1piperazine (Compound 4B) The title compound was prepared as described in Example 2 for Compound 2B, replacing Compound 4A for Compound 2A. Extraction of the alkalinised filtrate with dichloromethane, followed by purification by flash chromatography (ethyl acetate-2N ammonia in methanol 10: 1) afforded the title compound as an oil (78%_>).

1H-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

6.82-7.12 m 4H aromatic CHs

4.40 q 2H OCH2CF3

2.95-3.25 m 4H 2 piperazine CH2

2. 72-2.85 m 2H H2NCH2CH2CH2N

2.52-2, 72 m 4H 2 piperazine CH2S

2.38-2.52 m 2H H2NCH2CH2CH2N

1.55-1.80 m 4H H2NCH2CH2CH2N

c) 3-(2-chlorophenyl)-5-methyl-N-{3-[4-[2-(2,2,2-trifluoroethoxy)phenyll-l- piperazinyl]propyl}isoxazole-4-carboxamide

A mixture of 0.32 g of Compound 3B, 0.19 g of triethylamine, 0.31 g of

3-(2-chlorophenyl-5-methylisoxazole-4-carbonyl chloride (Lancaster) and 40 ml of dichloromethane was stiπed at 20-25°C for 24 hours. The solution was washed with 2N sodium hydrate (4 x 4 ml), dried over sodium sulphate and evaporated to dryness in vacuo. The crude was purified by flash chromatography (chloroform-2N ammonia in methanol 100:3) affording the title compound as an oil (67%>).

⁷H-N R (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

7.35-7.62 m 4H chlorophenyl CHs

6.82-7.12 m 4H trifluoroethoxyphenyl CHs

5.50-5.80 br 1H NH

4.40 1 2H OCH2CF3

3.22-3.42 m 2H NHCHj

2.88-3.15 m 4H 2 piperazine CII2S

2.78 s 3H CH3

2.35-2.63 m 4H 2 piperazine CH2S

2.10-2.35 m 2H CONHCH2CH2CH2N 1.45-1.75 m 4H CH2CH2CH2

EXAMPLE 5 (Compound E)

N-{3-[4-[5-Fluoro-2-(2,2,2-trifluoroethoxy)phenyll-l-piperazinyll-propyl}-3- methyl-4-keto-2-phenyl-4H-l-benzopyran-8-carboxamide

The title compound was prepared following the procedure described in Example 3, using N-(3-chloropropyl)-3-methyl-4-keto-2-phenyl-4H-l-benzopyran-8- carboxamide (prepared as described by Leonardi A. et al. in Patent US 5,474,994), instead of Compound 3D and heating to 190°C for 30 minutes. Purification was caπied out by flash chromatography (chloroform/2N methanolic ammonia, gradient from 100:1 to 100:3) affording the title compound as an ivory solid (66.5%>). M.p. 162-166°C.

^JH-NMR (200 MHz) Spectrum, Solvent: CDCL3, Chemical shift (δ)

8.38 d 2H H5 andH7 7. 75-7.80 m 2H H2 and H6 of 2-phenyl ring

7.55-7.75 m 4H H3, H4 and H5 of 2-phenyl ring, CONH

7.50 t 1H H6

6.86 dd 1H trifluoroethoxyphenyl H3

6.50-6.70 m 2H trifluoroethoxyphenyl H4 and H6

4.31 1 2H OCH2CF3

3.50-3.65 m 2H CONHCH2CH2CH2

2.85-3.05 m 4H 2 piperazine CH2S

2.30-2.55 m 6H 2 piperazine CH2S, CONHCH2CH2CH2

2.20 s 3H CH3 1 1..6600--11..8855 mm 2H CH2CH2CH2

EXAMPLE 6 PHARMACOLOGICAL DATA Determination of affinity for cloned α,-adrenoceptor subtypes (α_la, _lb, α_ld) by radioligand binding assay

Determination of affinity for cloned subtypes of α, -adrenergic receptors was performed in membranes from cells transfected by electroporation with DNA expressing the genes encoding each α,-adrenoceptor subtype. Cloning and stable expression of the genes expressing α,-adrenoceptor subtypes were performed as previously described (Testa R. et al., (1995), Pharmacol. Comm. 6, 79-86, and cited references). The cell membranes were incubated in 50 mM Tris. pH 7.4, with 0.2 nM [ H]prazosin, in a final volume of 1.02 ml for 30 minutes at 25°C, in the absence or presence of test compounds (1 pM-10 μM). Non-specific binding was determined in the presence of 10 μM phentolamine. Incubation was stopped by addition of ice-cold Tris buffer and rapid filtration through 2%-polyethyleneimine-pretreated Schleicher & Schuell GF52 filters. Inhibition of specific binding of the radioligand by the drugs was analysed to estimate the IC₅₀ value by using the non-linear curve-fitting program Allfit (De Lean A. et al., 1978, Am. J. Physiol. 235, E97-E102). The IC₅₀ value was converted to an affinity constant (Ki) by the equation of Cheng Y. C. et al., 1973, Biochem. Pharmacol. 22, 3099-3108. Data were expressed as mean Ki.

Cystometry in conscious rats obstructed by partial urethra ligature.

In order to obtain a partial obstruction of the urethra, the method previously reported by Malgrem (Malgrem A. et al., 1987 and 1988, J. Urol. 137: 1291-1294; Neurourol. Urodyn. 6: 371 :380) was followed with minor modifications (Guarneri et al., 1991, Pharmacol. Res. 24: 263-272).

Female rats of the Sprague-Dawley strain [Crl:CD(SD)BR, from Charles River

Italia, Calco, Como, Italy] weighing 225-275 g were used. The animals were maintained in constant temperature and humidity conditions, on a forced 12-hour light-dark cycle and with food and water ad libitum for at least one week before the experiment.

After being anaesthetised with 3 ml/kg i.p. equitensin (pentobarbital 1.215 g, chloral hydrate 5.312 g, magnesium sulphate 2.657 g, ethanol 12.5 ml, propylene glycol 49.5 ml, distilled water to 125 ml of final volume), the rats were placed in a supine position and the bladder and urethra were exposed via an incision in the shaven abdomens and gently pulling away the muscle portion. The urethra was cannulated with a polyethylene tube with an outside diameter of 1.22 mm, and the urinary bladder was then emptied and, via the cannula introduced through the urethra, filled with physiological saline. A silk (Ethicon 3/0) ligature was placed around the urethra with the cannula inside and the intraurethral cannula was then removed. The abdominal incision was sutured and, immediately after the operative procedure, antibiotic medication (penicillin G 200 000 I.U./kg i.p. and streptomycin 260 mg/kg i.p.) was performed.

Three weeks after the procedure for partially obstructing the urethra, the animals were prepared for cystometry by surgical insertion into the bladder of a catheter, through which the bladder was gradually filled.

The rats, anaesthetised with equitensin 3 ml/kg i.p., were placed in a supine position and, via an incision of about 10 mm in the abdominal wall, the urinary bladder was exposed and gently freed from suπounding tissues. The urinary bladder was emptied manually and cannulated, via a small incision at the bladder top, with a polyethylene cannula (type PE-50, 0.58 mm I.D. x 0.96 mm O.D.), which was permanently secured to the bladder with silk thread.

The cannula was exteriorised through a subcutaneous tunnel in the retroscapular area, where it was fastened with a plastic adapter, in order to avoid the risk of removal by the animal. After washing the urinary bladder with physiological saline, the catheter was sealed using a small flame and the abdominal incision was sutured.

To allow evaluation of the effect of a test compound after intravenous administration, the jugular vein was cannulated with a polyethylene cannula (type PE- 50, 0.58 mm I.D. x 0.96 mm O.D.) filled with heparinised physiological saline. As for the bladder catheter, this cannula, too, was exteriorised, secured and sealed in the retroscapular area.

Two days after the operation, the rats, fasted overnight, were placed in Bollman's cages or in Bollman's cages modified so as to have an opening in the bottom to allow collection of urinated fluid. After an adaptation period of 20 minutes, the free end of the bladder cannula was connected to a pressure transducer and a special apparatus which allowed infusion into the urinary bladder of physiological saline at 37°C at a constant rate of

10 ml/hour. Intravesical pressure changes caused by bladder filling were recorded by the pressure transducer which was connected to a recording polygraph.

From the cystometrograms, the frequency and mean amplitude of spontaneous bladder contractions not inducing micturition, termed «unstable-bladder contractions)) (UBC), within 2 minutes prior to micturition were evaluated.

The frequency and amplitude of "UBC" were generally evaluated in one/two reproducible cystometrograms recorded before treatment and considered as baseline values.

After obtaining baseline cystometrograms, the compounds were administered.

The effect of the test compounds on ineffective emptying contractions was evaluated in the first, second and third cystometrograms after treatment. The highest percent change observed was considered to be a useable result.

Cystometry in conscious rats with partial urethra obstruction revealed detrusor contractions which were ineffective in urine expulsion (non-micturition contractions = unstable-bladder contractions (UBC)). This model is reported in the scientific literature as related to the lower-urinary-tract symptoms occuπing in humans having obstructive urethral syndromes (Michel, 2000, Drugs of Today. 386 (Supp. B2): 3-6).

The compounds used as comparisons for compounds A-D in binding and physiological studies included known compounds such as terazosin, prazosin and tamsulosin. Other compounds used in these studies include the following:

RESULTS

The results obtained with compounds having different receptor-affinity profiles are shown in Tables 1 and 2.

Generally, non-selective α,-blockers (prazosin, terazosin) induced a marked and dose-dependent reduction in the number and amplitude of non-effective micturition contractions.

Tamsulosin, a compound partially selective for the α,_d-adrenergic subtype, was found to be very potent. Its potency may be related to its higher affinity for this subtype.

The selective α,_a-subtype antagonists (Rec 15/2739, 27/01 10) as well as the α,_d-subtype selective compounds (Rec 26D/038, 26D/073) were poorly active as inhibitors of unstable-bladder contractions.

Compounds having selectivity for the α,_a and α,_d subtypes versus the _lb subtype (Compound B and Compound D) proved to be more potent than the molecules selective only for the α,_a subtype or the α_ld subtype.

TABLE 1

Cystometry in conscious rats with partial urethral obstruction. Effects on non- effective micturition contractions. Data represent the percent inhibition of frequency and amplitude of non-effective contractions observed for 2 minutes before micturition. Affinity of test compounds for α-adrenoceptor subtypes is also shown in table.

Table 2.

Cystometry in conscious rats with partial urethral obstruction. Effects on non- effective micturition contractions. Data represent number (frequency) and amplitude (mmHg) of non-effective micturition contractions observed for 2 minutes before micturition.

n (number of rats/group); Dose (mg kg); p<0.05; ** p<0.01 versus baseline values (before treatment).

EXAMPLE 7 Effect of study compounds in patients with lower-urinary-tract symptoms.

Efficacy of compounds A, B, C, D and E in the treatment of lower-urinary- tract symptoms was tested in patients with these symptoms. Compounds A-E were administered orally once or twice daily at doses of 5, 12.5, 25 and 100 mg for a period of 40 days. Total daily dosages, therefore, were 5, 10, 12.5, 25, 50, 100 or 200 mg.

The therapeutic effect of compounds A-E was measured by a questionnaire completed by the patients, which was used to determine, for example, micturition frequency, the number of micturition episodes during the night, the extent of difficult urination, the pain or feeling of discomfort in the lower abdominal tract or genital areas.

The efficacy of compounds A-E was measured on the basis of any amelioration observed for each symptom associated to lower-urinary-tract symptoms compared to a control group of patients who were administered placebo with the same administration method and regime.

Claims

1. A method for the treatment of upper-urinary-tract symptoms (LUTS) in a mammal, including a human, in need of such treatment, the method including administration to said mammal of a therapeutically-active dose of a ligand of α,-adenergic receptors where such ligand binds to α_la-adrenergic receptors with an affinity at least 10 times greater than that for a,_b-adrenergic receptors, and, also, such ligand binds to α_ld-adrenergic receptors with an affinity at least 6 times greater compared to α_lb-adrenergic receptors, and such ligand is not tamsulosin.

2. A method according to Claim 1, wherein the ligand binds to α_la-adrenergic receptors with an affinity which is 1 to 10 times greater than the affinity for α,_d-adrenergic receptors.

3. A method according to Claim 1, wherein the ligand binds to each of α,_a- and α_ld-adrenergic receptors with an affinity at least 10 times greater than that for α_lb-adrenergic receptors.

4. A method according to Claim 3, wherein the ligand binds to each of α,_a- and α_ld-adrenergic receptors with an affinity at least 20 times greater than that for α_lb-adrenergic receptors.

5. A method according to Claim 1, wherein the ligand is an α, -adrenergic antagonist.

6. A method according to Claim 1, wherein such ligand has a Ki for α,_a-adrenergic receptors which ranges from 0.01 to about 100 nM.

7. A method according to Claim 1 , wherein such ligand has a Ki per α_ld-adrenergic receptors ranging from 0.01 to about 100 nM.

8. A method according to Claim 1, wherein such ligand has a Ki for each of expand α,_d-adrenergic receptors ranging from 0.01 to about 100 nM.

9. A method according to Claim 8, wherein such ligand has a Ki for α,_a-adrenergic receptors ranging from 0.05 to about 10 nM and a Ki for α_ld-adrenergic receptors ranging from 0.1 to about 10 nM.

10. A method according to Claim 1, wherein such ligand has an affinity for α,_d-adrenergic receptors which is less than 10 times lower than the affinity for α_la-adrenergic receptors.

1 1. A method according to Claim 1, wherein such ligand is administered by the oral, transdermal, parenteral, intravenous, intramuscular, subcutaneous or transmucosal routes or by inhalation.

12. A method according to Claim 1, wherein such ligand is administered as part of a pharmaceutically-acceptable composition.

13. A method according to Claim 1, wherein such ligand is administered at a dose of about 0.05 - 50 mg/kg/die.

14. A method to identify a compound which is a candidate for the treatment of LUTS in a mammal, including a human, the method comprising the following steps: a) establishing that a test compound binds to α,_a- and α,_d-adrenergic receptors with an affinity at least 6 times higher compared to α_lb-adrenergic receptors; and b) establishing that a test compound having the characteristics described in a) is a candidate for the treatment of LUTS.

15. A method according to Claim 14, wherein such test compound is identified as a candidate for the treatment of LUTS by evaluation of its effects in an animal model system.

16. A method according to Claim 15, wherein such animal model system evaluates the effect of such test compound on unstable-bladder contractions.

17. A method for the treatment of LUTS in a mammal, including a human, in need of such treatment, the method including exposure of tissues of the lower urinary tract of such a mammal to a therapeutically-effective amount of a ligand which binds to α_la- and α,_d -adrenergic receptors with an affinity at least 6 times higher compared to a,_b-adrenergic receptors

18. A method according to Claims 1 or 17, wherein the ligand is used for the treatment of iπitative LUTS.

19. A method according to Claims 1 or 17, wherein the ligand is used for the treatment of obstructive LUTS.

20. A method according to claims 1 or 17, wherein the ligand is used for the treatment of LUTS due to BPH.

21. A method according to Claims 1 or 17, wherein the ligand is used to treat NLUTD.

22. A method according to Claims 1 or 17, wherein the ligand is administered with an anticholinergic agent.

23. A method according to Claims 1 or 17, wherein the ligand administered is a

compound of formula I where

R is an aryl, cycloalkyl or polyhaloalkyl group,

R, is an alkyl, alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethane- sulphonyloxy group; each of R₂ and R₃ independently represent a hydrogen atom or a halogen, or an alkoxy or polyfluoroalkoxy group, and n is 0, 1 or 2.

24. A method according to Claims 1 or 17, wherein the ligand administered is a compound of formula II

where:

R₄ represents an alkyl, alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethane-sulphonyloxy group; each of R₅ and R_<; independently represent a hydrogen or halogen atom or a polyfluoroalkoxy or alkoxy group;

R₇ represents one or more substituents being a hydrogen or halogen atom or an alkyl, alkoxy, nitro, amino, acylamino, cyano, alkoxycarbonyl or carboxamido group;

R₈ represents a hydrogen atom or an alkyl group or an arylalkyl group; and n is 0, 1 or 2.

25. A method according to Claims 1 or 17, wherein the ligand administered is a compound of formula III

where:

R₉ represents a phenyl, alkoxycarbonyl, alkylcarbonyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl, cyano or alkoxycarbonylamino group;

R_l0 represents an alkyl. alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethane-sulphonyloxy group; each of R_n and R₁₂ independently represent a hydrogen or halogen atom or a polyfluoroalkyl, polyfluoroalkoxy, cyano or carbamoyl group; and n is 0, 1 or 2; with the proviso that, if R, represents a phenyl group and both R_π and R,₂ represent hydrogen and/or halogen atoms, then R,₀ represents a polyfluoroalkoxy or trifluoromethanesulphonyloxy group.

26. Use of a compound characteristically binding to α,_a-adrenergic receptors with an affinity at least 10 times higher compared to α,_b-adrenergic receptors and binding to α,_d-adrenergic receptors with an affinity at least 6 times greater compared to α_]b-adrenergic receptors, excluding tamsulosin, for the preparation of a medication for the treatment of LUTS.

27. Use according to Claim 26 of a compound which binds to α_la-adrenergic receptors with an affinity from 1 to 10 times greater than the affinity for α,_d- adrenergic receptors.

28. Use according to Claim 26 of a compound which binds to each of α,_a- and α_ld-adrenergic receptors with an affinity at least 10 times greater than the affinity for α_lb-adrenergic receptors.

29. Use according to Claim 26 of a compound which binds to each of α,_a- and α_ld-adrenergic receptors with an affinity at least 20 times greater than the affinity for α_lb-adrenergic receptors.

30. Use according to Claim 26 of a compound which is an antagonist of α,_a-adrenergic receptors.

31. Use according to Claim 26 of a compound which has a Ki for α_la-adrenergic receptors ranging from 0.01 to about 100 nM.

32. Use according to Claim 26 of a compound which has a Ki for α,_d-adrenergic receptors ranging from 0.01 to about 100 nM.

33. Use according to Claim 26 of a compound which has a Ki for each of α,_a- and a,_d-adrenergic receptors ranging from 0.01 to about 100 nM.

34. Use according to Claim 33 of a compound which has a Ki for α_la-adrenergic receptors ranging from 0.05 to about 10 nM and a Ki for α_Id-adrenergic receptors ranging from 0.1 to about 10 nM.

35. Use according to Claim 26 of a compound which has an affinity for α_Id- adrenergic receptors which is less than 10 times lower than the affinity for α_la- adrenergic receptors.

36. Use according to Claim 26 of a compound which is administered by oral, transdermal, parenteral, intramuscular, intravenous, subcutaneous or transmucosal administration or by inhalation.

37. Use according to Claim 26 of a compound which is administered as part of a pharmaceutically-acceptable composition.

38. Use according to Claim 26 of a compound which is administered at a dose ranging from 0.05 to 50 mg/kg/die.

39. Use according to Claim 26 of a compound of general formula I

where

R is an aryl, cycloalkyl or polyhaloalkyl group,

R, is an alkyl, alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethane- sulphonyloxy group; each of R₂ and R₃ independently represent a hydrogen atom or a halogen, or an alkoxy or polyfluoroalkoxy group, and n is 0, 1 or 2.

40. Use according to Claim 26 of a compound of general formula II

where:

R₄ represents an alkyl, alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethanesulphonyloxy group; each of R₅ and R₆ independently represent a hydrogen or halogen atom or a polyfluoroalkoxy or alkoxy group;

R₇ represents one or more substituents being a hydrogen or halogen atom or an alkyl, alkoxy, nitro, amino, acylamino, cyano, alkoxycarbonyl or carboxamido group;

R₈ represents a hydrogen atom or an alkyl group or an arylalkyl group; and n is 0, 1 or 2.

41. Use according to Claim 26 of a compound of general formula III

where:

R,, represents a phenyl, alkoxycarbonyl, alkylcarbonyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl, cyano or alkoxycarbonylamino group;

R,₀ represents an alkyl, alkoxy, polyfluoroalkoxy, hydroxy or trifluoromethane-sulphonyloxy group; each of R_n and R₁₂ independently represent a hydrogen or halogen atom or a polyfluoroalkyl, polyfluoroalkoxy, cyano or carbamoyl group; and n is 0, 1 or 2; with the proviso that, if R, represents a phenyl group and both R_π and R₁₂ represent hydrogen and/or halogen atoms, then R_I0 represents a polyfluoroalkoxy or trifluoromethanesulphonyloxy group.