ES2361938T3 - HYDROXIMETHYL-CARBAMOILALQUIL-KETONES PROTECTED BY SILILO AS INTERMEDIATE COMPOUNDS IN THE PREPARATION OF DOPAMINE-BETA-HYDROXYLASE INHIBITORS. - Google Patents

Abstract

A compound of formula III ** Formula ** where (1) when n means 2, R4 means hydrogen, an alkyl or alkylaryl group; R5 means an organosilyl group and R6 means a protective amino group; or (2) when n means 3, R5 means an organosilyl group; and NR4 R6 represents a phthalimido group; and wherein the amino protecting group is an alkyl carbamate or alkylaryl carbamate group; the term "alkyl" means hydrocarbon chains, linear or branched, containing from one to six carbon atoms, optionally substituted with aryl, alkoxy, halogen, alkoxycarbonyl or hydroxycarbonyl groups; the term aryl means a phenyl or naphthyl group, optionally substituted with an alkoxy, halogen or nitro group; and the term halogen means fluorine, chlorine, bromine or iodine

Description

This invention relates to intermediate compounds as defined in the claims useful for obtaining peripherally selective dopamine-mina-hydroxylase inhibitors and their method of preparation.

In recent years, interest in the development of dopamine--hydroxylase (DβH) inhibitors has focused on the hypothesis that inhibition of this enzyme can provide significant clinical improvements in patients suffering from cardiovascular disorders such as hypertension or chronic heart failure The rationale for the use of DβH inhibitors is based on their ability to inhibit the biosynthesis of norepinephrine, which is achieved via enzymatic hydroxylation of dopamine. The activation of neurohumoral systems, particularly the sympathetic nervous system, is the main clinical manifestation of congestive heart failure (Parmley, W. W., Clinical Cardiology, 18: 440-445, 1995). Patients with congestive heart failure have elevated plasma concentrations of norepinephrine (Levine, TB et al., Am. J. Cardiol., 49: 1659-1666, 1982), an increased central sympathetic flow (Leimbach, WN et al., Circulation, 73: 913-919, 1986) and an increased overflow of cardiorenal norepinephrine (Hasking, GJ, et al., Circulation 73: 615-621, 1966). Excessive and prolonged exposure of the myocardium to norepinephrine can lead to downregulation of cardiac adrenoceptors 1, remodeling of the left ventricle, arrhythmias and necrosis, all of which may decrease the functional integrity of the heart. Patients with congestive heart failure who have high concentrations of plasma norepinephrine also have the most unfavorable long-term prognosis (Cohn, J.N., et al., N. Engl. J. Med., 311: 819-823, 1984). Of greater significance is the observation that plasma concentrations of norepinephrine are already high in asymptomatic patients who do not have overt heart failure and can predict the resulting mortality and morbidity (Benedict, CR, et al., Circulation, 94: 690- 697, 1996). This implies that the activated sympathetic tone is not only a marker of congestive heart failure, but could contribute to the progressive worsening of the disease.

Inhibition of sympathetic nerve function with adrenoceptor antagonists seemed a promising approach, however a significant proportion of patients do not tolerate the immediate hemodynamic deterioration that accompanies -blocker treatment (Pfeffer, MA, et al., N. Engl. J. Med., 334: 1396-7, 19996). An alternative strategy to directly modulate sympathetic nerve function is to reduce the biosynthesis of norepinephrine via the inhibition of DβH, the enzyme responsible for the conversion of dopamine to norepinephrine in sympathetic nerves. This approach has several merits that include gradual modulation as opposed to abrupt inhibition of the sympathetic system, and that causes increased dopamine release, which improves renal function such as vasodilation, diuresis and renal natriuresis. Therefore, DβH inhibitors can provide significant advantages over conventional -blockers.

To date, some DβH inhibitors have been described in the literature. The first first and second generation examples such as disulfiram (Goldstein, M., et al., Life Sci., 3: 763, 1964) and diethyldithiocarbamate (Lippmann, W., et al., Biochem. Pharmacol., 18 : 2507, 1969) or fusaric acid (Hidaka, H. Nature, 231, 1971) and aromatic or alkyl thioureas (Johnson, GA, et al., J. Pharmacol. Exp. Ther., 171: 80, 1970) they turned out to be of low potency, exhibited little selectivity for DβH and caused toxic side effects. However, the third generation of DβH inhibitors proved to have a much greater potency, such as the nepicastate (RS-25560-197, IC50 9 nM) (Stanley, WC, et al., Br. J. Pharmacol. , 121: 1803-1809, 1997), which was developed for the first clinical trials. Although it lacks some of the problems associated with the first and second generations of DβH inhibitors, a very important finding was that the nepicastato crossed the blood brain barrier (BBB), therefore capable of causing central effects , as well as peripherals, a situation that could lead to unwanted and potentially serious side effects of the drug in the central nervous system (CNS). Therefore, there is still an unmet clinical requirement for a potent, non-toxic, peripherally selective DβH inhibitor, which could be used for the treatment of certain cardiovascular disorders. A DβH inhibitor with similar or even greater potency than nepicastate, but devoid of effects on the CNS (unable to cross the BBB), could provide a significant improvement over all other DβH inhibitor compounds described to date in the prior art The patent document.

In a reference by Eckardt Wolf, et al ("5-hydroxypentane-2,3-dione and 3-amino-1-hydroxypropan-2-one, putative precursors of vitamin 86", CAN. J. CHEM., Vol. 75 , no.7, 1997, pages 942-948) new synthesis of 5-hydroxypentan-2,3-dione and 3-amino-1-hydroxypropan-2-one are described. The document also describes the compound [3-tert-butyldimethylsilyloxy) -2-oxo-propyl] -carbamic acid tert-butyl ester.

US-A-5438150 describes a process for converting 1,2,3,4-tetrahydronaphthalen-2-yl-amine with alpha hydroxymethyl ketones and KSCN in acetic acid to 1- (1,2,3,4-tetrahydronaphthalen-2-yl) -1,3-dihydroimidazol-2-thionas.

Surprisingly it has been found that the incorporation of some heteroatoms into the carbocyclic ring and / or elongation of the aminoalkyl side chain of the nepicastat core structure produces a series of compounds that have significant and pronounced effects of potential utility for DβH inhibition. .

Many of these compounds offer greater potency and significantly reduced brain access, leading to potent peripherally selective DβH inhibitors. Thus, the invention relates to intermediate compounds as defined in the claims for tools for obtaining compounds of general formula I;

image 1

Where R1, R2 and R3 are the same or different and mean hydrogens, halogens, an alkyl, alkyloxy, hydroxy, nitro, amino, alkylcarbonylamino, alkylamino or dialkylamino group; R4 means hydrogen, an alkyl or alkylaryl group; X means CH2, an oxygen or sulfur atom; n is 2 or 3 and the individual (R) - and (S) -enantiomers or mixtures of enantiomers and pharmaceutically acceptable salts thereof;

Unless otherwise indicated, in this specification the term alkyl (either used alone or in

10 combination with other moieties) means hydrocarbon chains, linear or branched, containing from 1 to 6 carbon atoms, optionally substituted by aryl, alkoxy, halogen, alkoxycarbonyl or hydroxycarbonyl groups; the term aryl (either used by itself or used in combination with other moieties) means a phenyl or naphthyl group, optionally substituted by alkyloxy, halogen or nitro groups; and the term halogen means fluorine, chlorine, bromine or iodine.

Some compounds are known according to formula II where X means methylene (CH2), oxygen or sulfur (Martinez, GR et al., U.S. Patent 5,538,988, equivalent to WO95 / 29165, Jul. 23, 1996; Eriksson, M., PCT Solic. Int. WO 9959988A1, Nov 25, 1999; Napoletano, M., PCT Solic. Int. WO 9608489A1, March 21, 1996; Sarda, N. et al., Tetrahedron Lett ., 17; 271-272, 1976; Neirabeyeh, M.AI et al., Eur. J. Med. Chem., 26: 497-504, 1991) in the literature and others can be prepared by those skilled in the art . The compounds

20 according to formula II are chiral and therefore formula II should be taken to represent both enantiomers (R) - and

(S) optically pure individual or mixtures of enantiomers;

image 1

Compounds of formula I are prepared by reacting a compound of formula II where X is CH2, oxygen

or sulfur; R1, R2 and R3 are the same or different and mean hydrogens, halogens, an alkyl, alkylaryl, alkyloxy, hydroxy, nitro, alkylcarbonylamino, alkylamino or dialkylamino group with a compound of formula III:

image 1

where n means 2 or 3; when n is 2, R4 means hydrogen, an alkyl or alkylaryl group; R5 means an organosilyl group and R6 means a protective amino group; when n means 3, R5 is defined as above but NR4 R6 represents a phthalimido group; and with a water soluble thiocyanate salt in an inert organic solvent and in the presence of an organic acid wherein the water soluble thiocyanate salt is an alkali metal thiocyanate salt or a tetraalkylammonium thiocyanate salt.

Suitable alkali metal thiocyanate salts include sodium, lithium and cesium thiocyanates, although potassium thiocyanate is preferred.

The compound of formula III where n is 1 is known (Wolf et al., Can. J. Chem., 75; 942-948, 1997) and the compounds of formula III where n is 2 or 3 are novel compounds that may be prepared by experts in the field (see examples). The organosilyl group may be chosen from the trialkyl, triphenylsilyl, phenyldialkylsilyl groups

or alkyldiphenylsilyl. The tert-butyldimethylsilyl group (TBDMS) is especially preferred. Preferred amino protecting groups (R6) include carbamates such as alkyl carbamates, in particular the t-butyl carbamate group (Boc) and alkylaryl carbamates. The reaction can be carried out with a small excess of the compound of formula III a and potassium thiocyanate (preferably 1.1-1.3 equivalents).

The reaction can be carried out in a substantially inert solvent (preferably ethyl acetate) and at different temperatures (preferably at the reflux temperature of the solvent). Preferred organic acids include acetic acid.

When compounds of formula III where n means 2 and R4 means hydrogen, the mixture of intermediates of formula V and VI is reacted with hydrochloric acid and ethyl acetate to provide the corresponding individual compounds of formula I (scheme 1) ; where R4 means alkyl (which includes aryl substituted alkyl), the individual intermediate of formula V is reacted with hydrochloric acid and ethyl acetate to provide the compounds of formula I.

When the compounds of formula III where n is 3 are used, the intermediate of formula VII is then treated with sodium borohydride in a suitable solvent system followed by acetic acid to remove the phthalimide protecting group as described in the literature (Osby et al., Tetrahedron Lett., 1984, 25 (20), 2093-2096) to provide the compounds of formula I (scheme 2). The compounds of formula I are obtained with good purity, but if preferred they can be recrystallized from a suitable solvent.

Scheme 1 Scheme 2

image 1

image 1

Pharmaceutically acceptable, inert vehicles are mixed with the active compounds for the preparation of the pharmaceutical compositions of the compounds of formula I. Pharmaceutically acceptable vehicles can be solid or liquid. Solid form preparations include powders, tablets, dispersible granules and capsules. A solid carrier can be one or more substances which can also act as diluents, flavoring agents, solubilizers, lubricants, suspending agents, binders or tablet disintegrating agents; It can also be an encapsulating material.

Preferably the pharmaceutical preparation is in the form of a single dose, for example a packaged preparation, the package containing discrete amounts of the preparation as packaged tablets, capsules and powders in vials or ampoules.

The doses can be varied depending on the requirements of the patient, the severity of the disease and the particular compound that is used. For convenience, the total daily dose can be divided and administered in portions throughout the day. It is expected that the most appropriate administration would be once or twice a day. The determination of the appropriate dose for each particular situation is within the experience of experts in medical practice.

Materials and methods

In vitro studies

DβH activity was assessed for its ability to b-hydroxylate dopamine to norepinephrine as previously described (Kojima, K., Parvez, S. and Nagatsu, T. 1993. Analysis of enzymes in catecholamine biosynthesis. In Methods in Neurotransmitter and Neuropeptide Research, pp. 349-380: Elsiever Science Publishers). SK-N-SH cells (ATCC HTB-11), a cell line derived from human neuroblastoma, were used as a source of human DβH. SK-N-SH cells cultured in 24-well plates were pre-incubated for 20 min in a reaction medium containing 200 mM sodium acetate, 30 mM N-ethylmaleimide, 5 mM copper sulfate, 0.5 mg aqueous catalase solution / ml, 1 mM pargiline, 10 mM sodium fumarate and 20 mM ascorbic acid. The cells were then incubated for an additional 45 min in the reaction medium with the addition of increasing amounts of dopamine (from 0.5 to 100 mM). During preincubation and incubation the cells were continuously shaken and kept at 37 ° C. The reaction was terminated by the addition of 0.2 M perchloric acid. Acidified samples were maintained at 4 ° C before injection to high pressure liquid chromatograph for the norepinephrine assay. In the experiments carried out in order to study the effects of the new DβH inhibitors on their enzymatic activity, compounds of interest (from 0.3 to 10,000 nM) were added to the preincubation and incubation solutions; The incubation was performed in the presence of a concentration (50 mM) of dopamine 2.5 times the corresponding Km value as determined in the saturation experiments.

5 Studies in vivo

Male NMRI mice or Wistar rats from Harlan-Interfauna (Spain) were obtained and kept 10 and 5 per cage, respectively, under controlled environmental conditions (12 h light / dark cycles and ambient temperature of 22  1 ° C). Food and tap water was supplied ad libitum and experimentation was carried out during daylight hours.

10 At the time equal to 0 h, animals were administered either the compounds to be tested at a given dose or the vehicle (water) administered orally via forced feeding. At 2, 6, 9, 12, 18 and 24h after the dose, the animals were sacrificed by decapitation and isolated, weighed and stored in a volume of 0.2 M perchloric acid for 12 h at 4 ° C in the dark the heart (right atrium and left ventricle) and the brain (frontal and parietal cortex). After incubation, the resulting supernatants were collected by centrifugal filtration of

15 incubated (0.2 mM / 10 min / ~ 5000 rpm, 4 ° C). The supernatants were stored frozen at -80 ° C until analysis. The quantification of dopamine and norepinephrine in the supernatants was performed by high pressure liquid chromatography with electronic detection.

Results

In vitro studies

20 Incubation of SK-N-SH cells in the presence of increasing concentrations of dopamine resulted in a concentration-dependent norepinephrine formation, yielding values of Km (in mM) and vmax (in nmol mg protein-1 h-1 ) of 20.61.6 and 153.84.4, respectively. A concentration of dopamine close to saturation was chosen from these kinetic parameters for use in inhibition studies. As detailed in Table I, compounds 2, 3, 4, 5, 6, 7, 8, 10, 12, 16, 19, 24, 26, 28 and 29 are those that were found to inhibit

25 markedly the activity of DβH. Compounds 2, 3, 4, and nepicastate 1 (reference compound) produced a concentration dependent decrease in -hydroxylation of dopamine with IC50 values in the low nM range versus DβH activity human (see Table 2). For subsequent in vivo studies, compound 4 was chosen, this being the compound most closely related to nepicastate 1, in order to provide conclusive evidence that the structural modifications made to the molecule

As part of the present invention, they are responsible for the marked and surprising improvement of the observed biological properties.

Table 1. Effect of the chosen compounds (5 mM) on the activity of DβH in SK-N-SH cells. The values are given as% of the control.

No.

Media + SEM  No. Media + SEM

one

0.0 + 0.3 24 0.0 + 1.9

2

1.6 + 0.3 25 66.0 + 4.5

3

4.1 + 0.6 26 4.5 + 1.9

4

3.3 + 0.3 27 15.5 + 5.8

5

8.1 + 0.3 28 2.6 + 1.6

6

6.9 + 0.6 29 2.2 + 2.5

7

8.0 + 0.1 30 99.4 + 2.8

8

9.4 + 0.7 31 27.3 + 0.4

9

50.2 + 1.9

10

8.2 + 0.7

eleven

36.7 + 4.4

12

3.0 + 0.5

13

94.0 + 3.1

14

77.9 + 2.2

fifteen

86.1 + 2.7

16

0.0 + 0.6

17

53.2 + 3.9

18

94.8 + 1.2

No.

Media + SEM  No. Media + SEM

19

6.9 + 0.5

twenty

16.8 + 4.8

twenty-one

124.8 + 6.5

22

17.8 + 2.1

2. 3

54.5 + 9.9

Table 2. IC50 values (in nM) for the inhibition of DβH in SK-N-SH cells.

Compound

IC50 (in nM)

2

60 (14,250)

3

91 (56,147)

4

105 (69,161)

Nepicastato 1

36 (2,846)

In vivo studies

Mouse

Experiments over time for compound 4 and nepicastate (1) in the heart at 100 mg / kg suggest

5 that both compounds are long lasting. The maximum effect time (Tmax) for the reduction of norepinephrine in tissue by 4 and 1 seems to be at 9 h post-dose (Figure 1). Then, noradrenaline tissue levels recover, reaching 50% recovery from initial tissue levels at 24 h.

At Tmax (9 h after administration), 4 and 1 reduced norepinephrine levels in a dose-dependent manner in the left ventricle. For both 4 and 1, the maximum inhibitory effect was reached at a dose of 100 mg / kg.

10 In contrast to what was found in the heart, 4 did not affect norepinephrine tissue levels in the cerebral parietal cortex, while 1 produced a dose-dependent decrease in norepinephrine levels in this area of the brain (Figure 2).

Rat

As shown in the mouse, the effects of 4 and 1 on norepinephrine were dose dependent

15 administered and reached their maximum at 9 am. (data not revealed). However, as shown in Figure 3, the inhibitory effects of 4 (100 mg / kg) on norepinephrine levels, both in the left atrium and ventricle, were more pronounced than those caused by 1 (100 mg / kg) As observed in the mouse, again 4 did not affect the norepinephrine tissue levels in the parietal cortex and in the frontal cerebral cortex, while 1 produced a marked decrease in norepinephrine levels in these brain areas.

20 It is concluded that 4, in severe contrast to nepicastate 1, exerts its inhibitory effects on DβH exclusively on the periphery, lacking inhibitory effects on the brain.

Reference is now made to the accompanying drawings, in which:

Figure 1 is a graph showing the time-dependent decrease of norepinephrine levels in the left ventricle of mice treated orally with 100 mg / kg of 4 or nepicastate 1. The symbols are the means

25 of 5 determinations per group; the vertical lines indicate the standard error of the mean (SEM).

Figure 2 contains two graphs showing the levels of norepinephrine in the left ventricle and the cerebral parietal cortex of the mouse, 9 hours after oral administration of 4 or nepicastate 1. The symbols are the means of 5 determinations per group; the vertical lines indicate the SEM.

30 Figure 3 contains four graphs showing the levels of norepinephrine in the heart (left atrium and ventricle) and brain (frontal and parietal cortex) of the rat, 9 hours after oral administration of 4 or nepicastate 1. The columns are the means of 5 determinations per group; the vertical lines indicate the SEM.

conclusion

Some compounds of general formula I are very potent inhibitors of dopamine--hydroxylase and have

35 potentially valuable pharmaceutical properties in the treatment of some cardiovascular disorders, where a reduction in the enzymatic hydroxylation of dopamine to norepinephrine may be of therapeutic benefit, such as hypertension and chronic heart failure. The possibility of using a durable DβH inhibitor with limited access to the brain (CNS), such as compound 4 opens up new perspectives in the treatment of hypertension and chronic heart failure due to improved potency and selectivity of inhibition of DβH in the periphery.

The invention described herein is exemplified by the following preparation examples, which should not be interpreted to limit the scope of the description. Alternative routes and similar structures may be apparent to those skilled in the art.

Examples (only examples 11, 12, 13 and 43 are examples of the invention as claimed)

Example 1 (comparative)

(R) -5-Aminomethyl-1- (6,8-difluorochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride, compound 3, table 1)

A stirred mixture of (R) -6,8-difluorochroman-3-ylamine hydrochloride (0.22 g, 1.0 mmol), tert-butyl ester of [3- (tert-butyldimethylsilyloxy) -2-oxopropyl] Carbamic acid (0.33 g, 1.1 mmol), potassium thiocyanate (0.11 g, 1.1 mmol) and acetic acid (0.3 ml, 5 mmol) in ethyl acetate (0.3 ml) was maintained at reflux for 2 hours, it was cooled to room temperature, then washed with a solution of sodium bicarbonate, dried over anhydrous magnesium sulfate and evaporated in vacuo. The residue was purified by column chromatography on silica gel using the ethyl acetate-petroleum ether mixture as eluent. The resulting oil (0.23 g) was dissolved in ethyl acetate (2 ml), at this point a solution of 2M HCl in ethyl acetate (2 ml, 4 mmol) was added and the mixture was stirred for 2 hours at room temperature. The precipitate was removed by filtration and washed with ethyl acetate to give melting point crystals 192 ° C (decomposition).

Examples 2-3

By applying the technique described above and related procedures known to those skilled in the art and using the appropriate chroman-3-ylamine hydrochlorides, the following compounds were prepared:

(R) -5-Aminomethyl-1-chroman-3-yl-1,3-dihydroimidazol-2-thione hydrochloride (compound 24, table 1).

(R) -5-Aminomethyl-1- (6-hydroxychroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 22, table 1).

Example 4

(R, S) -5-Aminomethyl-1- (6-hydroxythiochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride.

A stirred mixture of 6-hydroxythiochroman-3-ylamine hydrochloride (0.22 g, 1.0 mmol), [3- (tert-butyldimethylsilyloxy) -2-oxopropyl] carbamic acid tert-butyl ester (0.33 g , 1.1 mmol), potassium thiocyanate (0.11 g, 1.1 mmol) and acetic acid (0.3 ml, 5 mmol) in ethyl acetate (0.3 ml) was refluxed for 2 hours, It was then cooled to room temperature, and washed with a solution of sodium bicarbonate, dried over anhydrous magnesium sulfate and evaporated in vacuo. The residue was purified by column chromatography on silica gel using the ethyl acetate-petroleum ether mixture as eluent. The resulting oil (0.25 g) was dissolved in ethyl acetate (2 ml), at this point a solution of 2M HCl in ethyl acetate (2 ml, 4 mmol) was added and the mixture was stirred for 2 hours at room temperature. The precipitate was removed by filtration and washed with ethyl acetate to give crystals, which decomposed without melting.

Example 5

(3,4-Dihydroxybutyl) carbamic acid tert-butyl ester

To a stirred solution of 4-amino-1,2-butanediol (2.10 g, 20 mmol) in ethanol (50 ml) at room temperature was added di-tert-butyldicarbonate (4.80 g, 22 mmol) in a portion. The resulting mixture was stirred at room temperature for two hours, then evaporated in vacuo and purified by column chromatography on silica using ethyl acetate-petroleum ether mixture as eluent to obtain a colorless oil.

Examples 6-7

By applying the technique described above and related procedures known to those skilled in the art and using the appropriate N-substituted 4-amino-1,2-butanediols, the following compounds were prepared:

(3,4-Dihydroxybutyl) methylcarbamic acid tert-butyl ester

(3,4-Dihydroxybutyl) benzylcarbamic acid tert-butyl ester

Example 8

[4- (tert-Butyldimethylsilyloxy) -3-hydroxybutyl] carbamic acid tert-butyl ester

To a stirred solution of tert-butyl ester of (3,4-dihydroxybutyl) carbamic acid (2.60 g, 12.7 mmol), triethylamine (2.03 ml, 14.50 mmol) and 4- (dimethylamino) pyridine (0.05 g, 0.4 mmol) in anhydrous dichloromethane (40 ml) at room temperature, tert-butylmethylchlorosilane (2.0 g, 13.17 mmol) was added in one portion. The resulting mixture was stirred at room temperature for 18 hours, washed with water, brine and dried over anhydrous magnesium sulfate. Filtration and concentration in vacuo resulted in an oil which was purified by column chromatography on silica using ethyl acetate-petroleum ether mixture as eluent to obtain a colorless oil.

Example 9-10

By applying the technique described above and related procedures known to those skilled in the art and using the compounds of Examples 6 and 7, the following compounds were prepared:

[4- (tert-Butyldimethylsilyloxy) -3-hydroxybutyl] methylcarbamic acid tert-butyl ester

[4- (tert-Butyldimethylsilyloxy) -3-hydroxybutyl] benzylcarbamic acid tert-butyl ester

Example 11

[4- (tert-Butyldimethylsilyloxy) -3-oxobutyl] carbamic acid tert-butyl ester

To a solution of Dess-Martin periodinan (5.0 g, 11.8 mmol) in anhydrous dichloromethane (35 ml) at room temperature was added a solution of tert-butyl ester of the acid [4- (tert-butyldimethylsilyloxy) - 3-hydroxybutyl] carbamic (3.77 g, 11.8 mmol) in anhydrous dichloromethane. The resulting mixture was stirred at room temperature for one hour, evaporated in vacuo to one third of the initial volume and applied to a column filled with silica. Elution with ethyl acetate-petroleum ether as solvent gave a colorless oil.

Example 12-13

By applying the technique described above and related procedures known to those skilled in the art and using the compounds of Examples 9 and 10, the following compounds were prepared:

[4- (tert-Butyldimethylsilyloxy) -3-oxobutyl] methylcarbamic acid tert-butyl ester

[4- (tert-Butyldimethylsilyloxy) -3-oxobutyl] benzylcarbamic acid tert-butyl ester

Example 14

(S) -5- (2-aminoethyl) -1- (5,7-difluoro-1,2,3,4-tetrahydronaphthalen-2-yl) -1,3-dihydroimidazol-2-thione hydrochloride, compound 2 , Table 1)

A stirred mixture of (S) -5,7-difluoro-1,2,3,4-tetrahydronaphthalen-2-yl amine hydrochloride (0.17 g, 0.79 mmol), tert-butyl acid ester [4 - (tert-Butyldimethylsilyloxy) -3-oxobutyl] carbamic (0.28 g, 0.87 mmol), potassium thiocyanate (0.085 g, 0.85 mmol), water (0.014 ml, 0.80 mmol) and acetic acid ( 0.2 ml, 3.3 mmol) in ethyl acetate (2 ml) was refluxed for 7 hours, cooled to room temperature, washed with a solution of sodium bicarbonate and dried over anhydrous magnesium sulfate and evaporated empty The residue was purified by column chromatography on silica using the ethyl acetate-petroleum ether mixture as eluent. The resulting oil (0.24 g) was dissolved in ethyl acetate (2 ml), a solution of 2M HCl in ethyl acetate (2 ml, 4 mmol) was added and the mixture was stirred for two hours at room temperature. The precipitate was isolated by filtration and washed with ethyl acetate to give crystals, which decomposed without melting.

Example 15

By applying the technique described above and related procedures known to those skilled in the art and using the appropriate 1,2,3,4-tetrahydronaphthalen-2-ylamine hydrochlorides, the following compounds were prepared:

(S) -5- (2-aminoethyl) -1- (1,2,3,4-tetrahydronaphthalen-2-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 20, table 1)

Example 16

(R) -5- (2-aminoethyl) -1- (6,8-difluorochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 4, table 1)

A stirred mixture of (R) -6,8-difluorochroman-3-ylamine hydrochloride (1.68g, 7.58 mmol), [4- (tert-butyldimethylsilyloxy) -3-oxobutyl] carbamic acid tert-butyl ester (3.13 g, 9.85 mmol), potassium thiocyanate (0.96 g, 9.85 mmol), water (0.18 ml, 10 mmol) and acetic acid (3 ml, 50 mmol) in ethyl acetate (30 ml) was refluxed for 7 hours, cooled to room temperature, washed with sodium bicarbonate solution, dried over anhydrous magnesium sulfate and evaporated in vacuo. The residue was purified by column chromatography on silica using the ethyl acetate-petroleum ether mixture as eluent. The resulting oil (2.15 g) was dissolved in ethyl acetate (20 ml), a solution of 2M HCl in ethyl acetate (20 ml, 40 mmol) was added and the mixture was stirred for two hours at room temperature. The precipitate was isolated by filtration and washed with ethyl acetate.

to give crystals, which decomposed without melting. Example 17-37 By applying the technique described above and related procedures known to those skilled in

the technique and using the appropriate chroman-3-ylamine hydrochlorides and the appropriate [4- (tert-butyldimethylsilyloxy) -3-oxobutyl] carbamic acid tert-butyl esters, the following compounds were prepared: (R) -5- (2) Hydrochloride -aminoethyl) -1-chroman-3-yl-1,3-dihydroimidazol-2-thione (compound 12, table 1) (R) -5- (2-aminoethyl) hydrochloride -1- (6-hydroxychroman-3- il) -1,3-dihydroimidazol-2-thione (compound 16, table 1) (R) -5- (2-aminoethyl) -1- (8-hydroxychroman-3-yl) -1,3-dihydroimidazole hydrochloride 2-thione (compound 21, table1) (R) -5- (2-aminoethyl) -1- (6-methoxychroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 23, table1) (R) -5- (2-aminoethyl) -1- (8-methoxychroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 19, table 1) (R) -5- ( 2-aminoethyl) -1- (6-fluorochroman-3-yl) -1,3-dihydroimidazol-2-thione (compound 7, table 1) (R) -5- (2-aminoethyl) -1- (8 hydrochloride -fluorochroman-3-yl) -1,3-dihydroimidazol-2-thione (compound 6, table 1) (R) -5- ( 2-aminoethyl) -1- (6,7-difluorochroman-3-yl) -1,3-dihydroimidazol-2-thione (compound 8, table 1)

(S) -5- (2-aminoethyl) -1- (6,8-difluorochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 9, table 1) (R) -5- (2-aminoethyl) -1- (6,7,8-trifluorochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 10, Table 1)

(R) -5- (2-aminoethyl) -1- (6-chloro-8-methoxychroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 11,

Table 1) (R) -5- (2-aminoethyl) -1- (6-methoxy-8-chlorochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 13, Table 1)

(R) -5- (2-aminoethyl) -1- (6-nitrochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 18, table 1) (R) -5- (2-aminoethyl) -1- (8-nitrochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 17, table 1) (R) -5- (2-aminoethyl) -1- (6- (acetylamino) chroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 14,

Table 1)

(R) -5- (2-aminoethyl) -1- (6-hydroxy-7-benzylchroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 15, Table 1) (R) -5- (2-Benzylaminoethyl) -1- (6-methoxychroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 25,

Table 1)

(R) -5- (2-benzylaminoethyl) -1- (6-hydroxychroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 26, Table 1) (R) -1- (6-hydroxychroman-3-yl) -5- (2-methylaminoethyl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 27,

Table 1)

(R) -1- (6,8-Difluorochroman-3-yl) -5- (2-methylaminoethyl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 28, Table 1) (R) -1-Chroman-3-yl-5- (2-methylaminoethyl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 29, table 1)

Example 38 (R, S) -5- (2-aminoethyl) -1- (6-methoxythiochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 30, table 1) A stirred mixture of hydrochloride of 6-methoxythiochroman-3-ylamine (0.12 g, 0.50 mmol), tert-butyl acid ester

[3- (tert-Butyldimethylsilyloxy) -2-oxopropyl] carbamic (0.17 g, 0.55 mmol), potassium thiocyanate (0.055 g, 0.55 mmol), water (0.009 g, 0.5 mmol) and acid Acetic acid (0.2 ml, 3.3 mmol) in ethyl acetate (2 ml) was refluxed for 7 hours, cooled to room temperature, washed with sodium bicarbonate solution, dried over anhydrous magnesium sulfate and It evaporated under vacuum. The residue was purified by column chromatography on silica using the ethyl acetate-petroleum ether mixture as eluent. The resulting oil (0.12 g) was dissolved in ethyl acetate (1 ml), a solution of 2M HCl in ethyl acetate (1 ml, 2 mmol) was added and the mixture was stirred for 2 hours at room temperature . The precipitate was isolated by filtration and washed with ethyl acetate.

to give crystals, which decomposed without melting.

Example 39

By applying the technique described above and related procedures known to those skilled in the art and using the appropriate chroman-3-ylamine hydrochlorides, the following compounds were prepared:

5 (R, S) -5- (2-aminoethyl) -1- (6-hydroxythiochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 31, table 1)

Example 40

2- [3- (2,2-dimethyl [1,3] dioxolan-4-yl) propyl] isoindole-1,3-dione

To a stirred solution of 3- (2,2-dimethyl [1,3] dioxolan-4-yl) propylamine (1.05 g, 6.60 mmol) and carboethoxyphthalimide (1.45

10 g, 6.60 mmol) in acetonitrile (10 ml) at room temperature triethylamine (0.92 ml, 6.60 mmol) was added in one portion and the resulting mixture was stirred at room temperature for 18 hours, evaporated at vacuum and the residue was dissolved in ethyl acetate (50 ml). The solution was washed with brine, 10% citric acid solution and brine, then dried over anhydrous magnesium sulfate. Filtration and concentration in vacuo resulted in an oil that was purified by column chromatography on silica using the ethyl acetate-petroleum ether mixture as

15 eluent to obtain a colorless oil.

Example 41

2- (4,5-dihydroxypentyl) isoindole-1,3-dione

To a stirred solution of 2- [3- (2,2-dimethyl [1,3] dioxolan-4-yl) propyl] isoindole-1,3-dione (1.65 g, 5.70 mmol) in THF ( 20 ml) at room temperature a solution of 2N HCl (15 ml, 30 mmol) was added in one portion and the mixture

The resulting was stirred at room temperature for two hours, and then evaporated in vacuo to half the initial volume. The residue was saturated with NaCl and extracted with ethyl acetate. The organic phase was dried over anhydrous magnesium sulfate. Filtration and concentration in vacuo resulted in a colorless oil.

Example 42

By applying the technique described in Example 8 to 2- (4,5-dihydroxypentyl) isoindole-1,3-dione, the following compound was prepared:

2- [5- (tert-Butyldimethylsilyloxy) -4-hydroxypentyl] isoindole-1,3-dione

Example 43

By applying the technique described in example 11 to 2- [5- (tert-butyldimethylsilyloxy) -4hydroxypentyl] isoindole-1,3-dione, the following compound was prepared:

30 2- [5- (tert-Butyldimethylsilyloxy) -4-oxopentyl] isoindole-1,3-dione

Example 44

(S) -5- (3-Aminopropyl) -1- (5,7-difluoro-1,2,3,4-tetrahydronaphthalen-2-yl) -1,3-dihydroimidazol-2-thione hydrochloride (compound 5 , Table 1)

A stirred mixture of (S) -5,7-difluoro-1,2,3,4-tetrahydronaphthalen-2-ylamine hydrochloride (0.22 g, 1.0 mmol), 2- [5

35 (tert-butyldimethylsilyloxy) -4-oxopentyl] isoindole-1,3-dione (0.38 g, 1.05 mmol), potassium thiocyanate (0.11 g, 1.10 mmol), water (0.18 g , 1.0 mmol) and acetic acid (0.3 ml, 5.0 mmol) in ethyl acetate (3 ml) was refluxed for 7 hours, cooled to room temperature, washed with a solution of sodium bicarbonate , dried over anhydrous magnesium sulfate and evaporated in vacuo. The residue was purified by column chromatography on silica using the ethyl acetate-petroleum ether mixture as eluent. The resulting oil (0.18 g) was dissolved in a

40 mixture of isopropanol (5 ml) and THF (2 ml). Water (0.8 ml) and sodium borohydride (0.066 g, 1.74 mmol) were added at room temperature and the mixture was stirred for 1.5 hours. Acetic acid (0.6 ml, 10 mmol) was added and the solution was refluxed for two hours and then evaporated in vacuo to dryness. The residue was taken up in acetone, the solid was filtered to remove it, and the filtrate was acidified with a solution of 2N HCl in ethyl acetate. The precipitate was collected and washed with acetone to give crystals, which decomposed without

45 melt.

Example 45

(R) -5- (3-aminopropyl) -1- (6,8-difluorochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride

A stirred mixture of (R) -6,8-difluorochroman-3-ylamine hydrochloride (0.11 g, 0.50 mmol), 2- [5- (tert-butyldimethylsilyloxy) -4-oxopentyl] isoindole-1,3- dione (0.19 g, 0.55 mmol), potassium thiocyanate (0.055 g, 0.55 mmol), water (0.009 g, 0.50 mmol) and acetic acid (0.15 ml, 2.5 mmol) in Ethyl acetate (1.5 ml) was refluxed for 7 hours, cooled to room temperature, washed with a solution of sodium bicarbonate, dried over anhydrous magnesium sulfate and evaporated in vacuo. The residue was purified by column chromatography on silica using the ethyl acetate-petroleum ether mixture as eluent. The resulting oil (0.10 g) was dissolved in

5 the mixture of isopropanol (2.5 ml) and THF (1 ml). Water (0.4 ml) and sodium borohydride (0.038 g, 1.0 mmol) were added at room temperature and the mixture was stirred for 1.5 hours. Acetic acid (0.3 ml, 5 mmol) was added and the solution was refluxed for two hours and evaporated in vacuo to dryness. The residue was taken up in acetone, the solid was filtered to remove it, and the filtrate was acidified with a solution of 2N HCl in ethyl acetate. The precipitate was collected and washed with acetone to give crystals, which decomposed without melting.

10 Example 46

(R, S) -5- (3-aminopropyl) -1- (6-hydroxythiochroman-3-yl) -1,3-dihydroimidazol-2-thione hydrochloride

A stirred mixture of 6-hydroxythiochroman-3-ylamine hydrochloride (0.22 g, 1.0 mmol), 2- [5- (tert-butyldimethylsilyloxy) -4-oxopentyl] isoindole-1,3-dione (0.38 g , 1.05 mmol), potassium thiocyanate (0.11 g, 1.10 mmol), water (0.18 g, 1.0 mmol) and acetic acid (0.3 ml, 5.0 mmol) in acetate ethyl (3 ml) was refluxed for 7 hours, cooled to room temperature, washed with a solution of sodium bicarbonate, dried over anhydrous magnesium sulfate and evaporated in vacuo. The residue was purified by column chromatography on silica using the ethyl acetate-petroleum ether mixture as eluent. The resulting oil (0.17 g) was dissolved in the mixture of isopropanol (5 ml) and THF (2 ml). Water (0.8 ml) and sodium borohydride (0.066 g, 1.74 mmol) were added at room temperature and the mixture was stirred for 1.5 hours. Acetic acid (0.6 ml, 10 mmol) was added and the solution was

20 refluxed for two hours and then evaporated in vacuo to dryness. The residue was taken up in acetone, the solid was filtered to remove it, and the filtrate was acidified with a solution of 2N HCl in ethyl acetate. The precipitate was collected and washed with acetone to give crystals, which decomposed without melting.

Claims (5)

1. A compound of formula III image 1 where 5 (1) when n means 2, R4 means hydrogen, an alkyl or alkylaryl group; R5 means an organosilyl group and R6 means a protective amino group; or (2) when n means 3, R5 means an organosilyl group; and NR4 R6 represents a phthalimido group; and wherein the amino protecting group is an alkyl carbamate or alkylaryl carbamate group; the term "alkyl" means hydrocarbon, linear or branched chains containing from one to six carbon atoms, 10 optionally substituted with aryl, alkoxy, halogen, alkoxycarbonyl or hydroxycarbonyl groups; the term aryl means a phenyl or naphthyl group, optionally substituted with an alkoxy, halogen or nitro group; and the term halogen means fluorine, chlorine, bromine or iodine 2. A compound according to claim 1, wherein the organosilyl group is a trialkylsilyl, triphenylsilyl, phenyldialkylsilyl, tert-butyldimethylsilyl or alkyldiphenylsilyl group.

3. A compound according to claim 1 or 2, wherein the R6 protecting amino group is a t-butyl carbamate group.

Four.

2- [5- (tert-Butyldimethylsilyloxy) -4-oxopentyl] isoindole-1,3-dione.

5.

[4- (tert-Butyldimethylsilyloxy) -3-oxobutyl] benzylcarbamic acid tert-butyl ester.

6.

[4- (tert-Butyldimethylsllanyloxy) -3-oxobutyl] methylcarbamic acid tert-butyl ester.

20 7. [4- (tert-Butyldimethylsilyloxy) -3-oxobutyl] carbamic acid tert-butyl ester.