HU210071A9 - 4-alkylimidazole derivatives and anti-hypertensive use thereof - Google Patents

Description

Carini and Duncia in EPO 253 310, published January 20, 1988, disclose a class of imidazoles which are angiotensin II antagonists and are useful in the treatment of hypertension and congestive heart failure. The compounds are effective when administered by intravenous injection. Several compounds are effective orally. The general description includes certain 4-alkyl-2-propyl-1 - {[2 '- (1H-5-tetrazolyl) -4-biphenyl] methyl]} imidazoles which are in the 5-position of the imidazole ring. they are substituted with halogen, nitro, trifluoromethyl or cyano.

Carini, Duncia, and Wong, WO 89/06 233, published July 13, 1989, disclose the same class of angiotensin II antagonist imidazoles and even other angiotensin II antagonist imidazoles useful in the treatment of hypertension and congestive heart failure. Some of these compounds are also orally active. The general part of WO 89/06 233 includes compounds of the invention but does not specifically describe them.

Summary of the Invention

The present invention relates to 4-alkylimidazole derivatives which are unexpectedly potent antihypertensive agents when compared to the compounds specifically disclosed in International Patent Application EP-A 0 253 310 and International Application Publication No. WO 89/06233.

The compounds of the present invention are 4-alkyl-2-propyl-1 - [(2 '- (1H-5-tetrazolyl) -4-biphenylyl) methyl) imidazole-5-carboxaldehyde and -5- carboxylic acids having the formula

R ^{2 is} -CHO or -COOH; if

R ^{2 is} -CHO, then R ^{1 is} methyl, ethyl, isopropyl or tert-butyl; and if

R ^{2 is} -COOH, then R * is ethyl or isopropyl.

Due to excellent oral antihypertensive activity of the most preferred compounds of formula (I), wherein R ² is -CHO and R ¹ is ethyl or tert-butyl group and those wherein R ₂ is COOH and R is ethyl .

All of the compounds of the invention tested orally have the same or greater antihypertensive activity than any of the compounds specifically designated in EP-A-0 253 310 and WO 89/06 233. The most preferred compounds of the invention exhibit an orally active antihypertensive activity of about 2 to 4 times greater than the most potent, specifically designated, tested compounds of EP-A-0 253 310 and International Patent Application WO 89/06 233. .

The compounds of the invention are also highly effective antihypertensive agents when administered by intravenous injection.

The present invention relates to a method for the treatment of hypertension, wherein the compounds of the formula I are administered orally.

DESCRIPTION OF THE INVENTION Synthesis

Compounds of formula (I) may be prepared according to Scheme 1. An imidazole aldehyde (4) or an imidazole ester (5) is reacted with a suitably protected benzyl halide, tosylate or mesylate [(8): prepared according to U.S. Pat. No. 4,320,843] with a base such as potassium carbonate and in the presence of the like in a solvent such as dimethylformamide at 20-100 ° C for 1-48 hours. These alkylations result in a mixture of old isomers in which the main product is the old isomer of formula (I). The triphenylmethyl protecting group is removed with an aqueous acid such as hydrochloric acid, and if necessary, the ester group is saponified with aqueous hydroxide to give the compounds of the invention.

The intermediate aldehydes (4) and esters (5) can be prepared according to Scheme 2. The dialkylimidazoles (3) are prepared by classical Weiddenhagen imidazole synthesis. An alpha-hydroxy ketone (2) is then treated with butyraldehyde (1) in the presence of copper (II) acetate and ammonia. The hydroxymethylation of the compounds (3) is carried out using formaldehyde and aqueous acid as described in Kempe et al., U.S. Patent No. 4,278,801. The hydroxymethylimidazole intermediates are oxidized with a reagent such as manganese (IV) oxide or cerium (IV) ammonium nitrate to give the desired aldehydes (4). The esters (5) can be prepared by oxidizing the hydroxymethylimidazoles or aldehydes to the imidazole carboxylic acids and then esterifying the acids (to the person skilled in the art); or aldehydes (4) may be oxidized directly to the esters with NaCN / acetic acid / MnO _{2 in} methanol (Corey et al., J. Am. Chem. Soc., 90, 5616 (1968)).

Another process for preparing the imidazole esters (5) is illustrated in Scheme 3. This is a two-step synthesis in which an acetyl ester (7) is reacted with butamide oxime (8) and the addition intermediate is heated to 100-200 ° C in a solvent such as xylene, toluene or diphenyl ether [Paul, R. et al., J. Med. Chem.

28, 1704 (1985)].

The compounds of the present invention and their preparation are illustrated by the following examples, without, however, limiting the scope of the invention. In the examples, unless otherwise indicated, all parts and percentages are by weight or by weight.

Example 1

Part A: Preparation of 4 (5) -Ethyl-2-propylimidazole

For a mixture of 144 ml of butyraldehyde and 480 g of copper (II) acetate monohydrate, 2000 ml of 25% aqueous ammonia2

82.4 ml of 1-hydroxy-2-butanone are added dropwise in 0.5 ml of solution A9 at ’C with vigorous stirring. The reaction mixture was heated to 80-100 ° C for 0.5 h. The mixture was allowed to cool, the solvent was decanted and the residue was triturated with aqueous ethanol. The resulting greyish-green solid was filtered off.

Hydrogen sulphide gas was bubbled into an aqueous suspension of the above solid for 80 hours at 0.5 ° C. The mixture is then filtered while hot to give solid copper (I) sulfur ^. ifid will be removed. The filtrate was cooled and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and the filtrate was concentrated to give 10.1 g of product as a viscous oil. A small sample of the product was recrystallized into 1-chlorobutane / hexane to give a solid, m.p. 68.5-70 ° C. The remaining crude product is used without further purification for the following reactions.

NMR (200 MHz, CDC1 ₃₎ δ: 7.60 (br s, IH), 6.64 fs, IH), 2.61 (m, 4H), 1.73 (sext, 2H), first , 21 (t, 3ΗΚ®; · 94 (ζ 3Η).

Part B: Preparation of 4 (5) -Ethyl-5 (4) - (hydroxymethyl) -2-propylimidazole

A solution of 10.0 g of (4 S) -ethyl-2-propylimidazole, 6.0 g of 37 s formaldehyde, 32.5 g of concentrated hydrochloric acid and 43 ml of water is heated at reflux for 65 hours. The mixture was cooled, diluted with water and the resulting solution was adjusted to 10 with 10% aqueous sodium hydroxide and extracted with chloroform / 2-propanol (4: 1). The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated. The residue was chromatographed on silica gel, eluting with 10% methanol / chloroform + 0.2% concentrated ammonium hydroxide. The crystals were recrystallized from ethyl acetate to give 5.86 g, m.p. 159-160 ° C.

NMR (200 MHz, _DMSO-d6) δ: 11.28 (br s, IH), 4.62 (br s, IH), 4.26 (s, 2H), 2.47 (m, 4H ), / sext., 2H), 1.09 (t, 3H), 0.88 (t, 3H).

Part C: · Preparation of $ (5) -ethyl-2-propyl-itnidazole-5 (4) -carboxaldehyde

To a solution of 5.6 g of 4 (5 ^: j-ethyl-5 (4) - (hydroxymethyl) -2-propylimidazole) in 85 ml of glacial acetic acid at 25 ° C for 1.0 h was TZanl 1.0 N aqueous cerium A solution of (IV) -ammonium nitrate was added dropwise and the solution was poured into boiling syringes for 1.0 h at 25 ° C and the pH of the solution was adjusted with aqueous SCI (0.9 equiv.). After adjusting to a pH of about 5 and extracting with chloroform, the combined organic phases were washed twice with water, brine, dried over anhydrous sodium sulfate, filtered and concentrated to give 3.70 g of product as a yellow oil.

Őjpektrum NMR (200 MHz, CDC1 ₃₎ δ: 9.66 (s, IH), 2,93- 2.73 $ nu 4H), 1.79 (sext, 2H), 1.32 (t, 3H. ), 0.96 (t, 3H).

Part D: Preparation of 4-Ethyl-2-propyl-1 - {[2 - () H-5-tetrazolyl) -4-biphenyl] methylimidazole-5-carboxaldehyde

1.76 g of 4 (5) -ethyl-2-propylimidazole-5 (4) -carboxaldehyde, 2.95 g of anhydrous potassium carbonate, 6.95 g of 4 ^Z (bromomethyl) -2 - [(triphenyl) -methyl) -5-tetrazolyl] -biphenyl (purity -85%, prepared according to US 4,820,843) and 30 ml of dimethylformamide are stirred at 25 ° C for 22 hours. The reaction mixture was filtered, the filtrate concentrated in vacuo, the residue diluted with water and extracted with ethyl acetate. The combined organic layers were washed with water and brine, dried over anhydrous sodium sulfate, filtered and concentrated. The residue was chromatographed on a silica gel column eluting with ethyl acetate / benzene. 3.79 g of an alkylated product are obtained in the form of an oil.

A solution of the alkylated product (2.00 g) in 10% aqueous hydrochloric acid (25 ml) and tetrahydrofuran (50 ml) was stirred at 25 'Con for 18 hours. Excess aqueous sodium hydroxide was added to the reaction mixture and the solvents were removed in vacuo. The residue was dissolved in water and triphenylmethanol was filtered off from the solution. The filtrate was adjusted to pH 3-3.5 with 10% hydrochloric acid. The resulting slurry was stirred for several hours, then the solid product was filtered off and dried to give 0.97 g of product as a white amorphous material.

NMR (200 MHz, DMSO-d₆) δ 16.30 (br s, IH), 9.77 (s, IH), 7.72 to 7.51 (m, 4H), 7.02 ₍₂ B ₂ , 4H), 5.57 (s, 2H), 2.81 (quartet, 2H), 2.57 (t, 2H), 1.57 (sext., 2H), 1.23 (t, 3H) ), 0.86 (t, 3H).

Example 2

Part A: Preparation of methyl 4 (5) ethyl-2-propylimidazole-5 (4) carboxylic acid

A mixture of 4.24 g of methyl 2-pentinoate and 4.41 g of butamide oxime was stirred at 25 ° C for 18 hours. The reaction mixture was chromatographed on a silica gel column eluting with dichloromethane containing 0-10% methanol. 1.03 g of an oil are obtained. The xylene solution of the oil was heated under reflux for 24 hours. The solution was cooled, the solvent removed in vacuo and the residue chromatographed on silica gel, eluting with dichloromethane containing 0-5% methanol. 0.41 g of product is obtained in the form of a waxy solid.

NMR (300 MHz, CDC1 ₃₎ δ: 3.87 (s, 3H);

2.62 (t, 2H), 1.81-1.61 (m, 4H), 1.24 (t, 3H), 0.94 (t, 3H).

Part B: Preparation of methyl 4-ethyl-2-propyl-1 - {[2 '- (1,5-tetrazolyl) -4-biphenylyl] methyl} imidazole-5-carboxylic acid

The title compound was prepared from methyl 4 (5) -ethyl-2-propylimidazole-5 (4) -carboxylic acid according to Example 1 Part D.

NMR (300 MHz, CDC1 ₃₎ δ: 7.74 (m, IH), 7.50 to 7.23 (m, 3H), 7.03 (d, 2H), 6.86 (d, 2H) , 5.60 (s, 2H), 3.83 (s, 3H), 3.00-2.86 (m, 4H), 1,711.66 (m, 2H), 1.25 (t, 3H), 0.83 (t, 3H).

HU 210 071 A9

Part C: Preparation of 4-Ethyl-2-propyl-1 - {[2 '- (1H-5-tetrazolyl) -4-biphenylyl] methyl} imidazole-5-carboxylic acid 0.61 g of methyl 4-ethyl-2 -propyl-1 - {[2 '- (1H-5-tetrazolyl) -4-biphenylyl] methyl} imidazole-5-carboxylic acid, 5 ml 5% aqueous sodium hydroxide solution, 5 ml methanol and 15 ml of tetrahydrofuran was heated at reflux for 120 hours. The solution was cooled, the solvents removed in vacuo and the residue dissolved in water (100 mL). The solution was adjusted to pH 4 with 10% hydrochloric acid and extracted with methylene chloride / 2-propanol (4: 1). The combined organic phases were dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give 0.41 g of product as a glassy solid.

MMR (300 MHz, CDCl ₃ ) δ: 7.71-7.51 (m, 4H), 7.08 (m, 4H), 5.73 (s, 2H), 2.95 (quart, 2H). )

2.84 (t, 2H), 1.54 (m, 2H), 1.21 (t, 3H), 0.84 (t, 3H).

3-15. Examples 1 to 2 can be prepared as described in Examples 1 and 2 (Table 1).

Table 1

Compounds of formula (I) wherein R 1 and R _{2 are as} defined below

Example R. r ₂ MMR (300 MHz) Third methyl CHO the) 4th tert-butyl CHO b) 5th isopropyl CHO 6th isopropyl COOH

a) MMR (DMSO-d 6) δ: 9.75 (s, 1H), 7.71-7.50 (m, 4H), 7.02 (A ₂ B ₂ , 4H), 5.55 ( s, 2H), 2.55 (t, 2H), 2.40 (s, 3H), 1.56 (sext., 2H), 0.84 (t, 3H).

b) NMR (CDC1 ₃₎ δ: 10.13 (s, 1H), 7.99 (d, 1H), 7.51 (m, 2H), 7.41 (m, 1H), 7.14 (d, 2H), 6.96 (d, 2H), 5.60 (s, 2H), 2.81 (m, 2H), 1.73 (m, 2H), 1.50 (s, 9H) , 0.95 (t, 3H).

Dosage forms

The compounds of the invention may be administered for the treatment of hypertension by any means by which the active ingredient is brought into contact with the site of action in the body of a warm-blooded animal. For example, the compounds may be administered parenterally, i.e., subcutaneously, intravenously, intramuscularly or intraperitoneally. However, the compounds are preferably administered orally.

The compounds may be administered by any conventional means that can be used in conjunction with drugs, either individually or in combination with other drugs. The compounds may be administered alone but will generally be administered together with a pharmaceutical carrier. The carrier will be selected according to the route of administration selected and according to standard pharmaceutical practice.

As used herein, a "warm-blooded animal" is a member of the animal world that has a homeostatic mechanism, such as mammals and birds.

The dose administered will depend on the age, health and weight of the patient, the degree of the disease, the concomitant treatment, if any, the frequency of treatment, and the nature of the effect desired. The dosage of the active ingredient is generally about 1-500 mg / day. Generally, a dose of 10-100 mg / day is effective in one or more administrations to achieve the desired result. These doses are effective amounts for treating both hypertension and congestive heart failure, i.e., reducing blood pressure and improving the hemodynamic load on the heart, and alleviating blood flow.

The active ingredient may be administered orally in solid dosage forms such as capsules, tablets and powders, or in liquid dosage forms such as elixirs, syrups and suspensions. The active compounds may also be administered parenterally in sterile liquid dosage forms.

Gelatin capsules contain the active ingredient and powdered carriers such as lactose, starch, cellulose derivatives, magnesium stearate, stearic acid or the like. Similar diluents can be used to make tablets. Both tablets and capsules can be prepared as sustained release products, which release the drug continuously over several hours. The film-coated tablets may be sugar-coated to mask the unpleasant taste and protect the tablet from atmospheric influences, but the tablets may also be enteric-coated to selectively disintegrate the tablet in the gastrointestinal tract.

Liquid dosage forms for oral administration may contain flavoring and coloring agents to facilitate patient acceptance.

Suitable carriers for parenteral solutions are usually water, suitable oils, saline, aqueous dextrose (glucose) and similar sugar solutions and glycols such as propylene glycol or polyethylene glycols. Solutions for parenteral administration preferably contain a water-soluble salt of the active ingredient, suitable stabilizers and, if necessary, buffering agents. Suitable stabilizers include antioxidants such as sodium bisulfite, sodium sulfite or ascorbic acid, alone or in combination. Citric acid, its salts or the sodium salt of ethylenediaminetetraacetic acid may also be used. Parenteral solutions may also contain preservatives such as benzalkonium chloride, methyl or propyl paraben or chlorobutanol.

Suitable pharmaceutical carriers are described in Remington's Pharmaceutical Sciences, A. Osol., A standard reference in this field.

The following examples serve to illustrate pharmaceutical dosage forms for the administration of the compounds of the present invention.

capsules

A plurality of unitary capsules are prepared by filling standard two-part gelatin capsules with 100 mg of powdered active ingredient, 150 mg of lactose, 50 mg of cellulose and 6 mg of magnesium stearate each.

Soft gelatine capsules

Prepare a mixture of the active ingredient and a digestible oil such as soybean oil, cottonseed oil or olive oil

Injection of gelatin and a suitable pump into gelatin to form soft gelatine capsules containing 100 mg of active ingredient. The capsules are washed and dried.

tablets

A large number of tablets are prepared in the usual manner, with the unit dosage containing 100 mg of active ingredient, 0.2 mg of colloidal silica, 5 mg of magnesium stearate, 275 mg of microcrystalline cellulose, 11 mg of starch and 98.8 mg of lactose. Suitable coatings may be used to enhance the pleasant taste or delayed absorption.

Injection

A parenteral preparation suitable for injection is prepared by mixing 1.5% by weight of active ingredient with 10% by volume of propylene glycol. The solution is made up to volume with water for injection and sterilized.

Suspension

An aqueous suspension suitable for oral administration is prepared so that 5 ml of the suspension contains 100 mg of finely divided active ingredient, 100 mg of carboxymethylcellulose sodium, 5 mg of sodium benzoate, 1.0 g of sorbitol solution (U.S.P.) and 0.025 ml of vanillin.

Claims (5)

An antihypertensive compound of formula (I): R _{2 is} -CHO or -COOH; if R _{2 is} -CHO, then R 1 is methyl, ethyl, isopropyl or tert-butyl; and if R _{2 is} -COOH, then R! ethyl or isopropyl. The compound of claim 1, wherein R _{2 is} -CHO and R 1 is ethyl. The compound of claim 1, wherein R _{2 is} -CHO and R 1 is tert-butyl. The compound of claim 1, wherein R _{2 is} -COOH and R 1 is ethyl. 5. A method of treating hypertension in warm-blooded animals comprising administering to the animal an effective amount of a compound of claim 1 for reducing the blood pressure of the animal.