NO310917B1 - 11-Acetyl-12,13-dioxabicyclo [8.2.1.] - tridecone derivatives, processes for their preparation, and drug-containing such compounds - Google Patents

Description

The present invention relates to new N-substituted (2R, 3S, 4S, 5R, 6R, 10R, 11R)-3- [ (2, 6-dideoxy-3-C-methyl-3-0-methyl-α-L-ribohexopyranosyl)- oxy]-5-[3,4,6-trideoxy-3-amino-(3-D-xylohexopyranosyl)-oxy]-2,4,6,8,10-pentamethyl-11-acetyl-12,13-dioxabicyclo [8.2.1] tridec-8-en-l-one compounds with motilin-antagonistic properties and their acid addition salts, as well as medicaments containing these compounds and methods for the preparation of these compounds. The compounds according to the invention represent ring-limited N-desmethyl-N-isopropyl derivatives of erythromycin A with modified side chains.

As is well known, the antibiotic erythromycin A also has, in addition to its antibiotic effects, unwanted gastrointestinal side effects for antibiotics, e.g. a strong increase in contraction activity in the gastrointestinal tract with stomach and intestinal cramps, nausea, vomiting and diarrhoea.

Several experiments have shown that erythromycin A is converted so that derivatives are formed in which the antibiotic effect is practically no longer present, but which, however, maintains an effect that affects the motility of the gastrointestinal tract. From European patent no. 0 550 895 ring-limited N-desmethyl-N-isopropyl-erythromycin-A derivatives with gastrointestinally active motilin-agonistic properties are known.

From European patent application EP-A 382 472, similar ring-restricted erythromycin derivatives are also known which, however, show antibiotic effects.

The present invention has the task of developing new orally active ring-restricted derivatives of erythromycin A without antibiotic action and with properties that favorably influence the motility of the gastrointestinal tract with an improved action profile.

It has now been found that the new ring-restricted, N-des-methyl-N-isopropyl derivatives of erythromycin A, where the side chain in the 11-position of the cyclic basic structure is modified by oxidation, are not antibiotically active, but exhibit selective motilin agonistic properties and favorably stimulates the motility of the gastrointestinal tract and shows enhanced effects on the tone of the lower oesophageal sphincter and stomach tone.

Due to their action profile, the compounds according to the invention are suitable for the treatment of motility disorders in the gastrointestinal tract and are thereby distinguished by good compatibility and good oral activity.

The present invention thus relates to new (2R,3S,-4S, 5R, 6R, 10R, HR)-2,4,6,8,10-pentamethyl-11-acetyl-12,13-diox-abicyclo[8.2.1] tridec-8-en-l-one compounds of general formula I

in which

R<1> denotes hydrogen or methyl and

R<2> denotes hydrogen or lower alkanoyl,

as well as their stable and physiologically compatible acid addition salts.

When a substituent in compounds of formula I denotes or contains lower alkyl, this can be branched or unbranched and contain 1 to 4 carbon atoms.

Compounds of formula I, in which R 1 represents methyl, have been found to be particularly advantageous.

R 2 preferably denotes hydrogen. When R<2> denotes lower alkanoyl, acetyl is preferred.

The compounds of formula I can be prepared in a known manner in that, in a compound of general formula II, in which R<1> and R<2> have the meanings given above, the 2', 3'-dihydroxypent-2'-yl side chain in the 11-position on the cyclic basic structure, is transferred to an acetyl side chain by oxidative glycol cleavage, and if desired that in the obtained compound of formula I, in which R<1> denotes hydrogen, a methyl residue R<1> is introduced, or that from the obtained compound of formula I, in which R<1> denotes methyl, the methyl residue R<1> is cleaved off, and if desired that the free compounds of formula I are transferred to the stable acid addition salts, or that the acid addition salts are transferred to free compounds of formula I.

The oxidative glycol cleavage of the 2', 3'-dihydroxypent-2'-yl side chain in the 11-position on the cyclic basic structure from compounds of formula II can be carried out with suitable oxidizing agents, such as lead tetraacetate, in suitable solvents. Suitable solvents are non-polar or weakly polar solvents such as benzene, toluene or xylene. The reaction can be carried out at temperatures between 0°C and 40°C, preferably at room temperature.

The obtained compounds of formula I, in which R<1 >denotes hydrogen, can then, if desired, be alkylated in a known manner to the corresponding N-methyl compounds. The alkylation can be carried out in a known manner by reaction with a methyl halide, or carried out as reductive alkylation by reaction with formaldehyde under reducing conditions, and can e.g. is carried out in the presence of a reducing agent, e.g. a complex borohydride compound such as sodium cyanoborohydride, sodium triacetoxyborohydride or sodium borohydride. If desired, the alkylation can also be carried out by reaction with a methyl halide, especially methyl iodide, or a methyl sulphonic acid ester. The alkylation is preferably carried out in an organic solvent which is inert under the reaction conditions. Suitable solvents for the reductive alkylation are cyclic ethers such as tetrahydrofuran (= THF) or dioxane, aromatic hydrocarbons such as toluene or lower alcohols. The alkylation can be carried out at temperatures between room temperature and the boiling temperature of the solvent. By alkylation with a methyl derivative, e.g. a methyl halide such as methyl iodide, the reaction is preferably carried out in the presence of a base, such as e.g. an alkali metal carbonate or a tertiary organic amine.

The methyl residue R<1> can then, if desired, be cleaved from the compounds of formula I in which R<1> denotes methyl. The demethylation can be carried out in a known manner by treating the compounds with a halogen, especially iodine and/or bromine, in an inert solvent in the presence of a suitable base. Suitable as bases are e.g. alkali metal alcoholates, alkali metal hydroxides and alkali metal salts of weak organic acids.

The compounds of formula I can be isolated and purified in a known manner from the reaction mixture. Acid addition salts can normally be transferred into the free bases and these can, if desired, be transferred to pharmacologically compatible acid addition salts in a known manner. To reduce hydrolysis side reactions it is

in expedient to use only equivalent amounts of acids for salt formation.

Pharmacologically applicable acid addition salts of the compounds of formula I are e.g. their salts with inorganic acids, e.g. carbonic acid, hydrogen halides, especially hydrochloric acid, or organic acids such as lower aliphatic mono- or dicarboxylic acids such as maleic acid, fumaric acid, lactic acid, tartaric acid or acetic acid.

The starting compounds of formula II, in which R<2> denotes hydrogen, are known from EP-B 0 550 895 and can be prepared according to the methods described therein.

The starting compounds of formula II, in which R2 denotes lower alkanoyl, can be prepared in a known manner by reacting compounds of formula II, in which R<2> denotes hydrogen, with carboxylic acids of general formula III

in which R<3> denotes lower alkyl, or reactive derivatives of these acids. As reactive derivatives of acids with formula III, possibly mixed acid anhydrides and acid halides come into question. Thus, it can e.g. acid chlorides or acid bromides of the acids of formula III or mixed esters of the acids of formula III with organic sulphonic acids are used, e.g. with optionally halogen-substituted lower alkanesulphonic acids, such as methanesulphonic acid or trifluoromethanesulphonic acid, or with aromatic sulphonic acids such as e.g. benzenesulfonic acids or with benzenesulfonic acids substituted with lower alkyl or halogen, e.g. toluenesulfonic acids or bromobenzenesulfonic acids. The reaction can be carried out as acylation in an inert organic solvent under the reaction conditions, at temperatures between -20 °C and room temperature. Suitable solvents are di-lower alkyl ketones, e.g. acetone, halogenated hydrocarbons such as dichloromethane, or aromatic hydrocarbons such as benzene or toluene, or cyclic ethers such as THF or dioxane, or mixtures of these solvents.

The acylation can preferably, especially when an anhydride or a mixed anhydride of the acids of formula III with a sulphonic acid is used as acylating agent, be carried out in the presence of an acid-binding reagent. Suitable as acid-binding agents are e.g. inorganic bases such as alkali metal carbonates, e.g. potassium carbonate, or organic bases soluble in the reaction mixture, such as tertiary nitrogen bases, e.g. tert.-lower alkylamines and pyridines, such as e.g. triethylamine, tripropylamine, N-methylmorpholine, pyridine, 4-dimethylaminopyridine, 4-diethylaminopyridine or 4-pyrrolidinopyridine.

If desired, a methyl residue R<1> can be introduced in an obtained compound of formula II in which R1 denotes hydrogen, or in an obtained compound of formula II in which R<1> denotes methyl, the methyl residue R<1> can be cleaved off. Such methylations or demethylations can be carried out in a known manner, e.g. under the described conditions for the introduction or removal of a methyl group for the compounds of formula I.

The new compounds of formula I and their physiologically compatible acid addition salts have interesting pharmacological properties, in particular the stimulating motilin-agonistic properties for the motility of the gastrointestinal tract. They are distinguished here by a favorable effect profile with surprisingly good oral activity. They are without antibiotic effects and have a high selective affinity for motilin receptors, while in motilin-agonistically active dose ranges they show no practically relevant affinity for other receptors in the gastrointestinal tract, such as adrenaline, acetylcholine, histamine, dopamine or serotonin receptors. The compounds show surprisingly good liver compatibility, which makes them suitable for use over longer periods of time. To ensure a regulated digestion of the ingested food, the autonomic nervous system and the hormones in the gastrointestinal tract in a healthy state work together to achieve a regulated contraction activity in the gastrointestinal tract, not only directly after food intake, but also in an empty gastrointestinal tract. Motilin is a known gastrointestinal peptide hormone that stimulates the motility of the gastrointestinal tract and induces a coordinated motility throughout the gastrointestinal tract, both in the empty state as well as after food intake.

The compounds of formula I exhibit anti-motilin physiological effects, because they are active as agonists for motilin receptors. The compounds of formula I thus exhibit pronounced stimulating effects in the gastrointestinal tract and at the lower oesophageal sphincter. They cause in particular an acceleration of gastric emptying, an increase in gastric tone and a long-term increase in the resting tone of the oesophageal sphincter. Due to their anti-motilin action profile, the compounds are suitable for the treatment of disease states associated with motility disorders in the gastrointestinal tract and/or reflux of chyme from the stomach into the esophagus. The compounds of formula I are thus induced, e.g. in gastroparesis of various origins, disturbances of gastric tone, disturbances of gastric emptying and gastro-oesophageal reflux, dyspepsia and postoperative motility disorders

travels.

The gastrointestinally active properties of the compounds of formula I can be demonstrated by standard pharmacological test methods in vitro and in vivo.

Description of the test methods

1. Determination of the binding ability of the test compounds to motilin receptors.

The affinity of the compounds of formula I to motilin receptors is measured in vitro in a fraction of a tissue homogenate from rabbit atrium. What is determined is the displacement of radioactively labeled, iodinated motilin from the motilin receptor binding when using the test compounds.

The receptor binding studies are carried out after a modification of the method according to Borman et. al (Regulatory Peptides 15 (1986). 143-153). For the production of <125>iodine-labeled motilin, motilin is iodinated enzymatically in a known manner, e.g. analogous to the method according to Bloom et al. (Scand. J. Gastroenterol. 11. (1976) 47-52, using lactoperoxidase.

For isolation of the tissue homogenate fraction used in the test from rabbit antrum, the antrum is freed of mucous membranes, divided into small pieces and homogenized in 10-fold volumes of a cold homogenization buffer solution (50 mM Tris-HCl buffer,

250 mM sucrose, 25 mM KC1, 10 mM MgCl2, pH 7.4) with the addition of inhibitors (1 mM iodoacetamide, 1 uM pepstatin, 0.1 mM methyl sulfonyl fluoride, 0.1 g/l trypsin inhibitor, 0, 25 g/l bacitracin) with a homogenizer for 15 seconds at 1,500 rpm. minute. The homogenate is then centrifuged for 15 minutes at 1,000 g, the precipitate obtained is washed 4 times with homogenization buffer solution and finally resuspended in 0.9% sodium chloride solution (in a volume corresponding to a 5-fold weight amount of antrum). The thus obtained tissue fraction, which is termed "uncleaned membrane preparation", is used in the test.

For the binding experiment, 200 ul of the uncleaned membrane fraction (0.5 - 1 mg protein) is diluted in 400 ul of a buffer solution A (50 mM Tris-HCl buffer, 1.5% bovine serum albumin

(= bovine serum albumin, BSA), 10 mM MgCl2, pH 8.0) with 100 µl iodinated motilin in buffer solution B (10 mM Tris-HCl buffer, 1% BSA, pH 8) (final concentration 50 pM), in 60 minutes at 30 °C. The reaction is stopped by adding 3.2 ml of cold buffer solution B and bound and unbound motilin are separated from each other by centrifugation (1,000 g, 15 minutes). The precipitate obtained after the centrifugation as a pellet is washed with buffer solution B and counted in a gamma counter. The displacement studies are carried out by adding increasing amounts of test compound to the incubation medium. As a test compound solution, aqueous solutions are used which are prepared by suitable dilutions of 60 x 10"<4->molar aqueous stock solutions. Test compounds that are poorly soluble in water are first dissolved in 60% ethanol and this solution is diluted with so much water that the ethanol- the concentration in the test solution does not exceed 1.6 vol%. From the obtained measurement data, in the form of the IC50 for the respective test compounds, the concentration is determined which causes a 50% inhibition of the specific binding of the iodinated motilin to the motilin receptor. From this is calculated the corresponding pIC50 value. For the compounds according to examples 1 and 2, the pIC50 values indicated in the subsequent table 1 were determined according to the method described above. 2. In-vivo determination of the compounds' influence on stomach tone.

Stomach tone plays an important role in gastric emptying. An elevated stomach tone contributes to accelerated stomach emptying.

The effect of compounds on gastric tone is determined in beagles using a barostat which is connected to a plastic bag in the dog's stomach and which enables the measurement of volumes or pressures in the dog's stomach. With the barostat, the stomach volume is determined by constant pressure in the stomach, or the stomach pressure is determined by constant volume in the stomach. With increased gastric tone, a reduced gastric volume is determined at a certain pressure and an elevated pressure is determined at a certain volume. In the test model used for investigating the increase in gastric tone caused by the compounds, the change in gastric volume caused by the compounds is measured at constant pressure. The stomachs of the test animals are relaxed with the help of lipid supply, i.e. that stomach tone is reduced, whereby the stomach volume increases accordingly. As a measure of the compounds' increasing effect on stomach tone, the reduction that occurs after taking compounds due to increase in stomach tone, of the increased stomach volume due to the addition of lipid, measured in percent.

The compound according to example 1 showed in this test model, administered i.d. in the well compatible dose of 2.15 umol/kg, a reduction of the enlarged stomach volume after lipid administration of 59.5%. The oral administration of the above-mentioned test compound at the same dose of 2.15 µmol/kg caused an unusually marked reduction of the gastric volume, whereby the lipid-induced relaxation of the gastric volume was practically completely prevented. These findings can be regarded as significant indications that the compounds according to the invention have a particularly high, particularly high oral bioavailability. 3. In-vivo determination of the compounds' influence on resting tone in the lower oesophageal sphincter.

This determination is carried out on male, awake, fasting beagle dogs which, before the start of the experiment, were provided with an oesophageal fistula and a duodenal cannula. The pressure in the lower oesophageal sphincter is measured using a perfused catheter system with a side opening connected to a pressure gauge and a recorder. The catheter is passed down into the stomach through the oesophageal fistula and then pulled back manually, slowly (= pull-through manometry). When passing the catheter part with the side opening through the high-pressure zone in the lower oesophagus,

sf inks a peak is registered. From this peak, the pressure is determined in mm Hg.

In this way, the basal pressure 1 oesophageal sphincter is first determined as a control value. The test compound is then administered orally, and after 15 minutes the pressure at the lower oesophageal sphincter is measured at 2 minute intervals for a period of 60 minutes. The increase in pressure after addition of test compound, compared to the predetermined basal pressure, is calculated.

In this test, the basal tone in the esophageal sphincter increased by 143% with a dose of 0.464 µmol/kg of the compound according to Example 1. This effect was maintained throughout the test time of 60 minutes.

Due to their actions in the gastrointestinal tract, the compounds of formula I are suitable in gastroenterology as drugs for larger mammals, especially humans, for the prophylaxis and treatment of motility disorders in the gastrointestinal tract.

The doses to be used can be different and vary according to the condition to be treated and the form of administration. Parenteral formulations contain e.g. usually smaller amounts of active compound than oral preparations. For administration to larger mammals, especially humans, however, pharmaceutical forms with an active compound content of 1 - 100 mg per single dose suitable.

As a medicine, the compounds of formula I can be contained, together with usual pharmaceutical excipients, in galenic preparations, such as e.g. tablets, capsules, suppositories or solutions. These galenic preparations can be prepared according to known methods using common solid carriers, such as e.g. milk sugar, starch or talc or liquid diluents such as e.g. water, fatty oils or liquid paraffins, and using pharmaceutical common excipients, e.g. tablet disintegrants, solvents or preservatives.

The following examples provide a more detailed explanation of the invention.

Example 1: (2R, 3S,4S,5R, 6R, 10R, HR)-3-[(2,6-dideoxy-3-C-methyl-3-O-methyl-α-L-ribohexopyranosyl)-oxy]-5 - [3,4, 6-trideoxy-3-(N-methyl-N-isopropylamino)-p-D-xylohexopyranosyl)-oxy] - 2,4, 6, 8,10-pentamethyl-11-acetyl-12,13- dioxabicyclo [8.2.1]-tridec-8-en-l-one (compound of formula I, R<1> = methyl, R<2> = hydrogen. A) 100 g [2R(2'R,3,R ),3S,4S,5R,6R,10R,11R]-11-(2',3'-dihydroxypent-21-yl)-3-[(2,6-dideoxy-3-C-methyl-3-0 -methyl-α-L-ribohexopyranosyl)-oxy]-5- [3,4, 6-trideoxy-3-(N-methyl-N-isopropylamino)-p-D-xylohexopyranosyl)-oxy]-2,4, 6,8, 10-pentamethyl-12,13-dioxabicyclo [8.2.1] tridec-8-en-l-one (=compound of formula II, R<1> = methyl, R<2> = hydrogen) was dissolved in 2,500 ml toluene under a nitrogen atmosphere. To this mixture was added 100.0 g of lead tetraacetate and the resulting suspension was stirred for 5 hours at room temperature. The reaction mixture was then washed with saturated sodium hydrogen carbonate solution and was then washed so often with water that the wash water reacted neutrally. The organic phase was dried over sodium sulfate and evaporated under reduced pressure. Chromatography of the residue on silica gel (eluent: methyl tert-butyl ether = MTBE) gave 81.9 g of the title compound as a white powder, melting point = 198 - 200°C, optical rotation value [a]D<20> = - 24.6° (c - 1.0 in CH 2 Cl 2 ). B) 1.1 g of the compound prepared above was dissolved in 1 ml of acetonitrile. 0.17 g of malonic acid was added and the mixture was heated to 60-70°C. After dissolution of the solids, 10 mm MTBE was added and the mixture was heated for 5 minutes to the boiling point under reflux. Then 10 ml MTBE was added again and the mixture was allowed to cool to room temperature with stirring. The precipitated crystals were filtered off from the solution, washed twice with 10 ml of MTBE and dried at 60°C in vacuum. There was obtained 1.2 g of the molomalonate of the title compound, melting range: 115.6 - 174.6°C (blurred).

Example 2: (2R,3S,4S,5R,6R,10R,11R)-3-[(2,6-dideoxy-3-C-methyl-3-O-methyl-α-L-ribohexopyranosyl)-oxy]-5 -[3,4,6-trideoxy-2-O-acetyl-3-(N-methyl-N-isopropylamino)-p-D-xylohexopyranosyl)-oxy]-2,4,6,8,10-pentamethyl-11- acetyl-12,13-dioxabi-cyclo[8.2.1]tridec-8-en-l-one (compound of formula I,

R<1>= methyl, R<2> = acetyl).

A) 210.0 g of the starting compound from example 1

(= compound with formula II, R<1> = methyl, R<2> = hydrogen) was dissolved in 2.4 1 of acetone under a nitrogen atmosphere and 85.8 g of potassium carbonate was added. 63.4 g of acetic anhydride were added and the resulting suspension was stirred for 20 hours at room temperature. The reaction mixture was then poured into a mixture of 2400 g of ice and 1000 ml of water and stirred for 30 minutes. The aqueous phase was extracted 3 times with acetic acid ethyl ester, the organic phases were collected and excess solvent was evaporated in vacuo. Recrystallization of the obtained crude product from n-pentane gave 200 g of [2R(2'R,3'R),3S, 4S, 5R,6R,10R,11R]-11-(2',3'-dihydroxypent-21- yl)-3-[(2,6-dideoxy-3-C-methyl-3-0-methyl-α-L-ribohexopyranoxyl)-oxy]-5-[3,4, 6-trideoxy-2-0-acetyl- 3-(N-methyl-N-isopropylamino)-p-D-xylohexopyranosyl)-oxy]-2,4,6,8,10-pentamethyl-12,13-diox-sabicyclo[8.2.1]tridec-8-ene- l-one (= compound with formula II, R<1>= methyl, R2 = acetyl), melting point = 128 - 130°C. B) 10.1 g of the product obtained above was reacted with 9.1 g of lead tetraacetate in the same way as described in example 1. 6.0 g of the title compound was obtained as a white solid, melting point = 164°C, optical rotation value [a]D<20> = -23.2° (c = 1.0 in CH2C12).

Example I: (2R, 3S, 4S, 5R, 6R, 10R, HR)-3-[2,6-dideoxy-3-C-methyl-3-O-methyl-α-L-ribohexopyranosyl)-oxy]-5- [3,4,6-trideoxy-3-(N-methyl-N-isopropylamino)-p-D-xylohexopyranosyl)-oxy]-2,4,6,8,10-pentamethyl-11-acetyl-12,13-dioxabicyclo Capsules containing [8.2.1]-tridec-8-en-1-one: Capsules containing the active compound were prepared using the following excipients and ingredients per capsule: (2R,3S,4S,5R,6R, 10R, 11R)-3-[2,6-dideoxy-3-C-methyl-3-O-methyl-α-L-ribohexopyranosyl)-oxy]-5- [ 3,4,6-trideoxy-3-(N-methyl-N-isopropylamino)-p-D-xylohexopyranosyl)-oxy]-2,4,6,-8,10-pentamethyl-11-acetyl-12,13-dioxabicyclo [8.2.1] tridec-

The active compound, the corn starch and the milk sugar were processed into a homogeneous paste mixture using EE. The paste was pulverized and the resulting granulate was placed on a suitable plate and dried at 45°C to remove the solvent. The dried granulate was passed through a pulverizer and further mixed with the following excipients:

and then filled with 400 mg capsules (= capsule size 0).

Claims (5)

1. (2R,3S,4S,5R,6R,10R,HR)-2,4,6,8,10-pentamethyl-11-acety1-12,13-dioxabicyclo[8.2.1]tridec-8-ene -1-on connections, characterized in that they have the general formula i in which R<1> denotes hydrogen or methyl, R<2> denotes hydrogen or lower alkanoyl, and their physiologically compatible acid addition salts. 2. Compounds according to claim 1, characterized in that R<1> denotes methyl. 3. Compounds according to one of the preceding claims, characterized in that R 2 denotes hydrogen. 4. Medicine, characterized in that it contains a pharmacologically active amount of a compound according to claim 1 and common pharmaceutical auxiliary and/or carrier substances. 5. Process for the preparation of (2R,3S,4S,5R, 6R,10R,11R)-2,4,6,8,10-pentamethyl-11-acetyl-12,13-dioxabicyclo[8.2.1] tridec-8-en-l-one compounds of general formula I, in which R<1> denotes hydrogen or methyl, R<2> denotes hydrogen or lower alkanoyl, and their physiologically compatible acid addition salts, characterized in that the 2', 3'-dihydroxypent-2'-yl side chain in the 11-position of the cyclic backbone in a compound of general formula II in which R<1> and R<2> have the meanings given above, is transferred to an acetyl side chain by oxidative glycol cleavage, and if it is desired that a methyl residue R<1> is introduced into the obtained compound of formula I, in which R1 denotes hydrogen, or that the methyl residue R<1> is split off from the obtained compound of formula I, in which R1 denotes methyl, and if desired that free compounds of formula I are transferred in their stable acid addition salts, or that the acid addition salts are transferred in the free compounds of formula I.