SK24393A3 - Carboxylic acid esters with 2-amino-7-(1,3-dihydroxy- -2-propoxymethyl)purine, their preparation and use - Google Patents

Abstract

Compounds of the formula 1 <IMAGE> in which the radicals R<1> and/or R<2> independently of one another represent acyl radicals of the formula -C(=O)-R<3> (2> where R<3> denotes C1-C3-alkyl and one of the radicals R<1> and R<2> can also denote hydrogen, and their physiologically tolerable salts have an antiviral action.

Description

Technical field

The present invention relates to 2-amino-7- (1,3-dihydroxy-2-propoxymethyl) purine carboxylic acid esters, their production and use.

BACKGROUND OF THE INVENTION

It has already been known (see EP 452 630) that substituted purines of the general formula

have an antiviral effect.

SUMMARY OF THE INVENTION

It has now been found that certain carboxylic acid esters with substituted purines are particularly effective against viruses and, moreover, have a particularly pronounced bioavailability after oral administration.

The invention therefore provides compounds of the general formula

I

(D in which the radicals R ¹ or / and R ² independently represent an acyl residue of the formula II

- C (= O) - R ³ (II), wherein R ³ represents an alkyl having 1-3 carbon atoms and one of the radicals R ¹ and R ² may also be hydrogen as well as their physiologically acceptable salts.

Of particular interest are the abovementioned compounds of formula I wherein R ³ is methyl and one of R ¹ and R ² may also be hydrogen.

Of particular interest is the abovementioned compound of formula I wherein R ³ is methyl.

The compounds of formula I according to the invention may contain one or more chiral centers in the acyclic side chain. These compounds generally exist as racemates, but the preparation or isolation of the pure enantiomers is possible. The present invention therefore provides both pure enantiomers and mixtures thereof, such as the corresponding racemate.

Especially suitable for therapeutic purposes are the salts of the compounds according to the invention

3 of the invention are salts of physiologically acceptable acids such as acetic acid, lactic acid, malic acid, p-toluenesulfonic acid, methanesulfonic acid, isethionic acid, hydrochloric acid, sulfuric acid or phosphoric acid.

The present invention also relates to a process for the preparation of the compounds according to the invention which comprises:

d);

is reacted with a carboxylic acid of formula III

R ⁴ -COOH (III) wherein R ⁴ is C 1 -C 3 alkyl, with a water scavenger, with the addition of a base, in an organic solvent to give compounds of formula I, and then the monoester is separated by conventional methods and diester.

The above compound of formula I can be prepared, for example, as described in EP 452 860.

A preferred hygroscopic means for carrying out said reaction is e.g. dicyclohexylcarbodiimide. As a principle, e.g. N, N-dimethylaminopyridine or its derivatives.

Suitable organic solvents for carrying out the reaction are, for example, dimethylformamide, N-methyl-2-pyrrolidone, pyridine, dichloromethane or tetrahydrofuran.

For carrying out the reaction, the compound of formula (I ') is preferably dissolved or suspended in an organic solvent, and is preferably reacted gradually at 10 ° C to 40 ° C, at room temperature, with stirring, preferably with at least 2 equivalents, in particular 2.2. to 3 equivalents of the corresponding carboxylic acid, dissolved optionally in the corresponding solvent, with a catalytic amount, preferably 0.2 to 0.4 equivalents of N, N-dimethylaminopyridine and preferably at least 2 equivalents, especially 3 to 5 equivalents, of dicyclohexylcarbodiimide, subsequently The mixture is stirred for 1 to 24 hours, preferably 6 to 10 hours, at a temperature of -10 ° C to 50 ° C, preferably at room temperature to 40 ° C.

After this time, if necessary, another equivalent of the appropriate carboxylic acid, 0.2 equivalents of N, N-dimethylaminopyridine and 2 equivalents of dicyclohexylcarbodiimide are added and the mixture is stirred for a further 5 to 24 hours, preferably 5 to 10 hours. The precipitated dicyclohexylurea is then filtered off and the product isolated according to the invention. The isolation is carried out, for example, by chromatography or crystallization, preferably after concentration of the filtrate by chromatography, for example, over silica gel e.g. using a 9: 1 mixture of dichloromethane and methanol.

The monoesters can be obtained by monitoring the reaction by thin layer chromatography and prematurely interrupting, followed by purification of the product as described above by chromatography.

Alternatively, the necessary isolation of optically active compounds is accomplished by known methods.

The invention also relates to the use of the compounds of the formula I according to the invention as antiviral agents for the treatment or prophylaxis of viral diseases.

The compounds of the invention are particularly active against herpes simplex virus type 1, herpes simplex virus type 2, human

- 5 cytomegaly virus, murine cytomegaly virus, varicella 11a zoster virus, Epstein Barr virus and human herpes virus 6 (HHV-6).

The invention further relates to medicaments comprising at least one compound of the invention.

The medicaments according to the invention can be used preferably enterally (orally) but also parenterally (intravenously), rectally or locally (topically). They can be administered in the form of solutions, powders (tablets, capsules including microcapsules), ointments (creams or gels) or suppositories. Suitable excipients for these dosage forms are the customary pharmaceutical liquid or solid fillers and carriers, solvents, emulsifiers, glidants, flavorings, colorants and / or buffers. 0.1 to 10, preferably 0.2 to 8 mg / kg body weight is administered as a convenient dosage. They are conveniently administered in dosage units containing the least effective daily dose of the compounds of the invention, e.g. 30 to 300, preferably 50 to 250 mg.

Efficacy against systemic herpes simplex 1 (HSV-1) infection:

Specific pathogen-free NMRI mice weighing 15-18 g were infected intraperitoneally with HSV-1 and then treated with oral administration of the compounds of the invention starting 3 hours after infection and continuing twice daily for 4 days. Treatment success was assessed by disease progression and survival rate versus untreated infected control. This was applied in place of the compounds according to the invention by physiological saline solution. The observation period was two weeks. Table 1 shows the results of this experiment.

Table 1

Antiviral activity against HSV-1 in NMRI mice by oral administration

Example Dosage Mean Survival (/ µmol / kg) survival (days) group size

7 1 9 x 10 14 days 5/5 9 x 30 14 days 5/5 9 x 100 14 days 5/5 2 9 x 30 5/5 9 x 100 5/5 - formula I, 9 x 10 10.5 + 0.7 3/5 P. 1 = R 2 = H 9 x 30 9,5+ 1,3 1/5 ^ zlúče- 9 x 100 5/5 nina vzor- ca I ') inspection 9 x 10 7.8 ₊ 1.1 1/5

Determination of oral applicability

The rhesus monkeys were housed 24 hours prior to the start of the experiment in separate cages. 12 hours prior to the start of the experiment, food was removed, but the drinking water was freely available before and during the experiment. Two animals each received a compound of the invention, one animal of a compound of the formula I, each with 105 µmol / kg by means of a gastric tube in a volume of 5 ml of tap water. An additional 20 ml of water was additionally rinsed.

One animal received 42 µmol / kg of a compound of formula I at a concentration of 10 mg / ml in saline, by intravenous injection into the forelimbs.

A hind limb blood sample was taken at all time intervals within 24 hours after dosing.

The blood was kept at 4 ° C until precipitation and then centrifuged. The serum thus obtained was kept at -20 ° C until analysis of the sample. 200 µl of serum was added to the reaction vessel and diluted with 100 ml of water. After addition of 30 µl of 50% trichloroacetic acid, the mixture was stirred in a Vortex <^R> mixer and then centrifuged for 3 minutes. 50 .mu.l _of the resulting solution was analyzed by high performance liquid by chromatography.

Chromatographic separation:

Column: <Nucleosil Cie, 125 x 4.6 mm, mobile phase: phosphoric acid 0.01 molar, flow rate: 1.0 ml / minute, detection: fluorescence, ex: 310 nm, em: 360 nm, retention time: 3 , 5 minutes (compound of formula I, wherein R ¹ = R ² = H, a compound of formula I).

The calculation was made by evaluating the area under the data (AUD). The metabolic utility of the compound of Formula I after oral administration of the compound of Example 1 was on average 37.80% (34.47% and 41.16%), respectively. On administration of the compound of the example, the bioavailability of the compound of Formula I was achieved on average 20.11% (23.73% and 16.50%) (said compounds are metabolized in the body to compounds of Formula I).

The oral bioavailability, on the other hand, is only 15% on average.

Determination of oral bioavailability (mouse):

In mice, following oral administration of the compounds of the invention, the following bioavailability of the compound of the formula was found

Zlúče- process dose AUD <o - o o> biological after- nina applications [mg / kg i [(ugxmi n) / mlj užiteľnosť M from Formula I i. in. 25 13.39 100 p. about. 1OO 9.23 17.2 Example 1 i. in. 25 13.21 98.6 p. about. 100 27.32 51.1 Example 2 p. about. 100 36.03 67.3 Example 3 p. about. 100 38,40 71.7

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Compound of Formula I wherein R ¹ = P. ² = acetyl

1,2 <3 (5 mmol) of 2-amino-7- (1,3-dihydroxy-2-propoxy) methylpurine (a compound of formula I wherein R ¹ = R ² = = hydrogen, produced as described in of European Patent Application EP 452 680 A) is dissolved in 50 ml of anhydrous dimethylformamide. 0.63 ml (11 mmol) of acetic acid, 0.2 g (1.6 mmol) of N, N-dimethylaminipyridine and 3.96 g (19 mmol) of N, N-dicyclohexylcarboclimide are added successively and the mixture is stirred for 6 hours. hours at room temperature. After this time, 0.32 ml (5.5 mmol) of acetic acid, 0.1 g (0.8 mmol) of N, N-climethylaminopyridine and 1.98 g (9.5 mmol) of N, N - of dicyclohexylcarbodiimide and stirred at room temperature for a further 17 hours. The precipitated N, N -dicyclohexylurea is filtered off, the filtrate is concentrated in vacuo and the residue is chromatographed over silica gel using a 9: 1 mixture of dichloromethane and methanol as solvent. 1.51 g (93.5% of theory) of 2-amino-7- (1,3-bis-acetoxy-2-propoxy) methyl purine of melting point 158 DEG C. are obtained in the form of colorless crystals.

¹ H-NMR (270 MHz, d 6 -dmso) ppm: 8.65 (s, 1H), 8.43 (s, 1H), 6.27 (s, 2H), 5.68 (s, 2H) 4.15-3.86 (m, 5H), 1.83 (s, 6H)

A compound of formula I wherein R ¹ = B. ² = butanoyl

1.2 g (5 mmol) of 2-amino-7- (1,3-dihydroxy-2-propoxy) methyl purine (a compound of formula I wherein R ¹ = R ² = hydrogen, produced as described in European No. EP 452 680 A) is dissolved in 50 ml of anhydrous dimethylformamide. 1.0 ml (11 mmol) of butyric acid, 0.2 g (1.6 mmol) of N, N-dimethylaminopyridine and 3.96 g (19 mmol) of N, N-dicyclohexylcarbodiimide are added successively and the mixture is stirred for 6 hours at room temperature. After this time, 0.5 ml (5.5 mmol) of butyric acid, 0.1 g (0.8 mmol) of N, N-dimethylaminopyridine and 1.98 g (9.5 mmol) of N, N - of dicyclohexylcarbodiimide and stirred at room temperature for a further 17 hours. The precipitated N, N-dicyclohexylurea is filtered off, the filtrate is concentrated in vacuo and the residue is chromatographed over silica gel using a 9: 1 mixture of dichloromethane and methanol as solvent. 1.84 g (97.1% of theory) of 2-amino-7- (1,3-bis-butyryloxy-2-propoxy) methyl purine of melting point 123 DEG C. are obtained in the form of colorless crystals.

¹ H-NMR (270 MHz, d ₆ -dmso) ppm: 8.64 (s, 1H), 8.43 (s, 1H),

6.27 (s, 2H), 5.67 (s, 2H), 4.18-3.79 (m, 5H), 2.05 (t, 4H), 1.42 (m, 4H), 0 .83 (t, 6H)

Example 3

A compound of formula I wherein R ¹ = R ² = propanoyl

1.2 g (5 mmol) of 2-amino-7- (1,3-dihydroxy-2-propoxyjmetyl purine (compound of formula I, wherein R ¹ = R ² = H, prepared as described in European patent application EP 452 680 A) is dissolved in 50 ml of anhydrous dimethylformamide, followed by the addition of 0.82 ml (11 mmol) of propionic acid, 0.2 g (1.6 mmol) of N, N-dimethylaminopyridine and 3.96 g (19 mmol) of N , N-dicyclohexylcarbodiimide, and the mixture was stirred at room temperature for 6 hours after which time 0.41 ml (5.5 mmol) of proionic acid, 0.1 g (0.8 mmol) of N, N-dimethylaminopyridine and 1.98 g (9.5 mmol) of N, N-dicyclohexylcarbodiimide and stirred for a further 17 hours at room temperature. The precipitated N, N-dicyclohexylurea is filtered off, the filtrate is concentrated in vacuo and the residue is chromatographed over silica gel using dichloromethane 9: 1 methanol as solvent to give 1.53 g (87.2% of theory) of 2-amino-7- (1,3-bis-propionyloxy-2-propoxy) methyl purine, m.p. and 143 ° C as colorless crystals.

1H-NMR (270 MHz, ds-dmso) ppm: 8.64 (s, 1H), 6.28 (s, 2H), 5.67 (s, 2H), 4.13 (m, 2H), 4 0.03-3.89 (m, 3H), 2.10 (q, 4H), 0.92 (t,

6H)

Example 4

A compound of formula I wherein ^{J 1} -hydrogen and R ² = acetyl

Colorless crystals, mp 153 ° C, ¹ H-NMR (200 MHz, d <s-dm 50) ppm 8.62 (s, 1H), 8.40 (s, 1H),

6.23 (s, 2H), 5.63 (m, 2H), 4.85 (t, 1H), 4.15-4.00 (m, 1H), 3.95-3.83 (m, 1H), 3.72-3.60 (m, 1H), 3.40 (m, 2H), 1.73 (s, 3H)

Claims (7)

1. The carboxylic acid esters of 2-amino-7- (l, 3-dihydro-hydroxy-2-propoxymety1) purine of formula I (I) in which the radicals R ¹ and / or R ² represent independently of one another, acyl radicals of the formula II - C (= O) - R ³ (II), wherein R ³ represents alkyl of 1 to 3 carbon atoms and one of the radicals R ¹ and R ² may also be hydrogen as well as their physiologically acceptable salts. Compounds of formula (I) according to claim 1, characterized in that R ³ is methyl and one of the radicals R ¹ and R ² can also be hydrogen. Process for the preparation of the compounds of the formula I according to claim 1 or 2, characterized in that the compound of the formula I '(') is reacted with carboxylic acids of the formula III R ⁴ -COOH (III) wherein R ⁴ is C 1 -C 3 alkyl with a water scavenger such as N, N-dicyclohexylcarbodiimide with the addition of a base such as N, N-dimethylaminopyridine in a solvent such as dimethylformamide to give the compounds of formula (I), then the monoester and the diester are separated by conventional methods. Compounds of formula I according to claims 1 or 2 2 for use as an antiviral agent. Compounds of formula I according to claims 1 or 2 2 for use as an antiherpes agent. Medicament comprising at least one compound of the formula I according to claims 1 or 2. Use of compounds of the formula I according to claims 1 or 2 for the manufacture of medicaments against viral diseases.