CS274497B2 - Method of 10-dihydro-10-deoxi-11-azaerythronolides a preparation - Google Patents

Abstract

The solution concerns a method of preparation of 10-dihydro-10-deoxo-11-azaerythronolides A of general formula I, where R1 is alkyl or alkanoyl, always with 1 to 4 carbon atoms, R2, R3 and R4 are the same or different, i.e. hydrogen atom or alkanoyl with 1 to 4 carbon atoms, or eventually their pharmaceutically suitable salts with acids. The principle of the solution consists in reaction of 10-dihydro-10-deoxo-11-azaerythronolide A of formula III and aliphatic aldehyde of general formula IV, where R5 is hydrogen atom or alkyl with 1 to 4 carbon atoms, in presence of formic acid or hydrogen and catalyser based on precious metal, or eventually in acylation of obtained products by anhydrides of low-molecular-weight aliphatic acids, and eventually in conversion of the products into pharmaceutically suitable salts with acids. The compounds of general formula I show antiphlogistic effect and can be used as pharmaceuticals.<IMAGE>

Description

The present invention relates to a process for the preparation of biologically active compounds, 10-dihydrolO-dcOKn-11-azaerythronolides A and their pharmaceutically acceptable acid salts.

It is known that numerous antibiotics, in addition to their basic antiblottic effect, also exhibit anti-inflammatory properties. However, this property is usually not used in the treatment of inflammatory processes that are not caused by pathogenic microorganisms in order to avoid too rapid resistance of the microorganisms and possible hypersensitivity of the human organism to them. It is therefore necessary to find substances having an anti-inflammatory effect which, at the same time, do not have antibiotic properties. They are most often compounds whose chemical structure is not similar to that of antibiotics or can exceptionally be prepared from antibiotics by chemical transformation. Thus, D-penicillin derived from penicillin is known (Abraham et al., Nature, 151, 107 (1943) and Ruiz-Torres, Arzneimittel-Forsch., 24, 914 (1974)).

In _the prior art, 10-dihydro-10-deoxo-11-azaerythromycin was synthesized by Beckmann rearrangement of erythromycin A oxime, followed by reduction of the erythromycin A iminoether obtained (U.S. Pat. No. 4,328,334, 5/1982, Djokic et al., 3). Chem Soc Perkin Trans.

1, 1986, 1881). N-methyl-11-aza-10-deoxo-10-dihydroerythromycin A (GB Patent No. 094 293, Kobrehel and Djokic), a novel semisynthetic macrolide antibiotic, was prepared by reductive methylation of the obtained amine according to a modified Eschweiler-Clark method with formaldehyde in the presence of formic acid. A 15-membered azalactone ring that has been subjected to clinical trials under the generic name azithromycin. U.S. Pat. No. 4,464,527 (8/1984) describes a process for the preparation of N-ethyl- and N- (n-propyl) derivatives of 10-dihydro-10-deoxo-11-azaerythromycin A, which are also effective antibacterial agents.

By studying the prior art, the present inventors have found that 10-dihydro-10-deoxo-11-azaorythronolides A and in particular their N-alkyl derivatives, their salts or / and O-nobo) and the Ν, Ο-substituted alkanoyl derivatives have not been described.

The present invention provides a process for the preparation of 10-dihydro-10-deoxo-11-azaerythronolides A of formula I

where

R1 is an alkyl or alkanoyl group containing from 1 to 4 carbon atoms,

R 1, R 8 and R 4 are the same or different and are hydrogen or C 1 -C 4 alkanoyl, and optionally pharmaceutically acceptable acid addition salts thereof, characterized in that 10-dihydro-10-deoxo-11-azaerythronolide A of formula III

CS 274 497 B2

Η

CH

CH

3.

OH

CH (III) undergoes reductive alkylation

Αχ) formaldehyde in the presence of formic acid, or Ag) an aliphatic aldehyde of formula IV

R, 5

CHO (IV) wherein R ₅ is an alkyl group having 1 to 4 carbon atoms, in the presence of hydrogen and a noble metal catalyst, and then the substance obtained by Αχ) or A ₂ ) is optionally acylated with nitric aliphatic anhydrides, and optionally converting the obtained products into pharmaceutically acceptable acid salts.

Thus, the method of the present invention comprising reductive alkylation of a compound of Formula III can be carried out either

With formaldehyde in the presence of formic acid in an inert solvent; or

A ₂ ) with an aldehyde of formula IV in the presence of hydrogen and a noble metal catalyst in an inert solvent.

According to method (A) of the present invention, a compound of formula III is reacted with a 1- to 3-fold equimolar excess of formaldehyde in the presence of at least an identical amount of formic acid in an inert solvent such as acetone, halogenated hydrocarbons, preferably chloroform. ee to give a compound of formula I wherein R 1 is methyl and R ₂ , R ₃ and R ₄ are hydrogen.

Method A ₂ ) involves reductive alkylation of a compound of formula III with an aldehyde of formula IV in the presence of a noble metal catalyst in an inert solvent, for example a lower alcohol such as methanol or ethanol (95% w / w). In practice, the reaction is carried out with a 1- to 2-fold equimolar excess of aldehyde and 0.5 equivalents of noble metal catalyst, preferably Pd / C (palladium on carbon) (5% w / w). The reductive alkylation is carried out at a moderate temperature, for example 18-25 ° C, under a hydrogen atmosphere at an initial pressure of 1 to 3 MPa for 2 to 10 hours. After completion of the reaction, the catalyst is filtered off and the product is isolated in the usual manner, most preferably evaporation of the alcohol under reduced pressure and isolation of the product of formula I, wherein R 1 is lower alkyl and R ₂ , R 8 and R ₄ are hydrogen; an organic solvent such as methylene chloride, chloroform or carbon tetrachloride.

A specific group of compounds of formula I are the novel 10-dihydro-10-deoxo-11-azaerythronolides A of formula ΙΛ.

CS 274 497 B2

where is the same as R ^ af? ₂ and 3 and ^R @ 4 have the abovementioned meanings, and their pharmaceutically acceptable acid Aoli.

It should be noted that the compound of formula (I) wherein R 6 is hydrogen is per se known in the art (see Djokic et al., J. Cgem., Soc., Perkin Trans. 1, 1081 (1906)]. However, the inventors of the present invention have discovered a new, greatly improved process for its preparation according to the above process, as well as its medical use, which has not been known hitherto. The pharmaceutically acceptable acid salts of the compounds of formula I, 10-dihydro-10-deoxo-11-azaerythronolides A, which are also included within the scope of the invention, can be prepared by reacting the 10-dihydro-10-deoxo-11-azaerythronolides A with at least with an equimolar amount of a suitable acid, for example hydrochloric, hydrobromic, sulfuric, phosphoric, acetic, propionic, citric, succinic, benzoic, etc., optionally in the presence of a solvent inert under the reaction conditions. The salts are isolated by filtration provided they are not soluble in the inert solvent used or by precipitation, either by adding a non-solvent for the corresponding salt, or by evaporating the solvent, most often by lyophilization.

In vitro and in vivo tests have shown that the compounds of formula (I) show potent anti-inflammatory activity. Their anti-inflammatory effect was tested in vitro compared to diclofenac (DICL) and D-penicillamine (D-PEN), which are known anti-inflammatory agents, in the model of extracellular lysosomatic enzyme release by human polymorphonuclear leukocytes / Welssman. Med., 134, 149 (1971), Carevic, Agents and Actions 16, 407 (1985)] and the results are shown in the diagrams.

1, 2 and 3 show in vitro activity diagrams (FIG.

and 2) and in vivo (Fig. 3). In all diagrams, the x-axis shows the concentration and the y-axis shows the enzymatic activity expressed as% of total activity.

In Fig. 1 the symbols used have the following meaning:

Il <= immunocomplex

AZER = 10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A (I)

DESAZa 6-O-desosaminyl-10-dihydro-10-deoxo-11-methyl-11-azaerythromycin A (III)

DICL and diclofenac

D o D-penicillamine

A = lactate dehydrogenase

B and (I-glucoronidase

C-N-acetylglucosaminidase

CS 274 497 B2

In Figure 2, the symbols used have the following meaning:

IK e BSA / anti-BSA immunocomplex

DE and 10-dihydro-10-deoxo-11-azaerythronolide A

AE = 10-dihydro-10-deoxo-11-ethyl-11-azaerythronolide A

APR = 10-dihydro-10-deoxo-11- (n-propyl) -1-azaerythronolide A

ALA-3 and 4,6,13-O-triacetyl-10-dihydro-10-deoxo-11-azaerythronolide A

A and lactate dihydrogenase (LDH)

B = β-glucuronidase (β-Gluc)

C and p-N-acetylglucosaminidase (p-Glm).

In Figure 3, the symbols used have the following meaning:

FCA and Freund's complete adjuvant

AZER and 10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A (I)

DESAZa 6-O-desosaminyl-10-dihydro-10-deoxo-11-methyl-11-azaerythromycin A (III)

DICL and diclofenac

D-PEN = D-penicillamine

A and lactate dehydrogenase (LDH)

B and β-glucuronidase (β-Gluc)

C = β-N-acetylglucosaminidase (β-Glm)

It can be seen from the diagram in Fig. 1 that by hydrolyzing azithromycin and preparing the corresponding 6-O-desosaminyl derivative (DESAZ), a product with good anti-inflammatory activity is obtained.

At a concentration of 10 mg / kg desaza showed approximately equal activity as D-PEN in the concentration of 10 ^"7 mg / kg. Elimination of both sugar groups and synthesis of 10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A (AZER) yields a compound that strongly inhibits extracollular release of lysosomal enzymes from polymorphonuclear leukocytes with the same effect as D-PEN or - at a concentration ^-7 mg / kg - with stronger effect.

In in vitro assays, DICL does not affect extracellular enzyme release. The in vitro potency of N-ethyl- (AE) or N- (n-propyl) derivatives (APR) is somewhat lower compared to AZER (foreign diagram in Fig. 2). Neither acylation of AZER with acetic anhydride and preparation of 4, G, 13-triacetyl-10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A (ALA-3) will result in a significant change in in vitro potency.

In vivo assays were also performed in an adjuvant-induced arthritis model in rats / Perason et al., Arthritis Rheum., 2, 440 (1959) by Carevic, Publ. Yug. Acad. of Sci., 7, 415 (1965)]. From the diagram of Fig. 3, AZER significantly reduces the extracellular release of lysosomal enzymes into the synovial fluid in arthritis-induced adjuvant rats and has the same level of efficacy as D-PEN and significantly higher efficacy than DICL. DESAZ shows somewhat lower efficacy than D-PEN and DICL.

From the above results, it is clear that the in vivo method is comparable to in vitro tests. In these in vitro and in vivo assays, test substances do not appreciably affect the release of the enzyme lactate dehydrogenase (A), demonstrating that the cellular membrane is not clearly affected.

Anti-inflammatory activity was also measured on carragenine-induced paw edema in rats / Crunkhorn et al., Br. Pharm., 42, 392 (1971)].

The results obtained with the compounds of the formula I (Table 1) do not significantly exceed the results obtained with D-PEN and antylsalicylic acid (Acisal). The anti-inflammatory effect of N-ethyl- (AE) and N- (n-propyl) derivatives (APR) is at the level of AZER activity. O- and N, O-substituted derivatives of formula I, such as 4,6,13-triacetyl-10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A (ALA-3) or 10-dihydro-10 hydrochloride -deoxo-11-methyl-azaorythrolidide A (AZER.HCl) shows higher potency compared to D-PEN and almost the same potency as acetylsalicylic acid.

CS 274 497 B2

Table 1

The anti-inflammatory effect of the novel azaerythronolides of the present invention

Compound n Paw Swelling Induced Dose (mg / kg) p.o. carragenine in rats% inhibition DE 4 50 29 AZER 6 50 29 AE 4 50 32 APR 5 50 25 ALA-3 5 50 34 AZER.HC1 5 50 38 D-PEN 4 50 28 Acetylsalicylic acid 22nd 50 40

n and number of groups (5 rats in each group)

DE-10-dihydro-10-deoxo-11-azaerythronolide A

AZER-10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A

AE - 10-dihydro-10-deoxo-11-ethyl-11-azaerythronolide A

APR-10-dihydro-10-deoxo-11- (n-propyl) -l-azacrythro-ulole A

ALA-3 -4,6,13-triacetyl-10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A

AZER.HCl - 10-dihydro-10-dsoxo-11-methyl-11-azasrythronolide hydrochloride A

The present invention is illustrated, but not limited, by the following examples.

Example 1

10-Dihydro-10-deoxo-11-azaerythronolide A

A mixture of 10-dihydro-10-deoxo-11-azaerythromycin A (100 g, 136.05 mmol), 6M HCl (750 mL) and CHCl ₃ (380 mL) was heated at reflux for 16 hours. After cooling to room temperature, the layers were separated and the aqueous layer was extracted with chloroform (2 x 100 mL). The aqueous solution was adjusted to pH 5.0 by addition of aqueous sodium hydroxide solution and re-extracted with chloroform (3 x 100 mL). The same procedure was repeated at pH 8.5 (3 x 250 mL). The chloroform extracts at pH 8.5 were dried. potassium carbonate and evaporated under reduced pressure to give 53.77 g (94.2%) of crude 10-dihydro-10-deoxo-11-azaerythronolide A. After crystallization from diethyl ether (300 ml), 34.45 g of homogeneous solid are obtained. product (thin layer chromatography, C 8 H 8: CHCl 3: CH 3 OH 40: 55: 5, NH ₃ , R ^ 0.233) having the physicochemical constants described in □. Chem. Soc., Perkin Trans. 1, 1881 (1986).

Example 2

10-Dihydro-10-deoxo-11-methyl-11-azaerythronolide A

To a solution of 10-dihydro-10-deoxo-l-azaerythronolide A (1 g, 2.38 mmol) in CHC1 ₃ (20 ml) was added 0.184 ml (2.38 mmol) of formaldehyde (36%) and 0.183 ml (4 , 77 mmol) of formic acid (98-100; j) and the reaction mixture is heated to boiling with stirring for 8 hours. The reaction mixture was cooled to room temperature and allowed to stand for 24 hours, after which the precipitated crystals were filtered off, washed with chloroform and dried. 1.0 g (96.5%) of crude 10-diCS 274 497 B2 hydro-10-deoxo-11-methyl-11-azaerythronolide A is obtained. The product is optionally recrystallized from chloroform (thin layer chromatography, 0.306). Melting point: 208-210 ° C. ¹ H-NMR (CD 3 OD): 2.351 ppm (N-CH ₃ ).

Example 3

10-Dihydro-10-deoxo-11-ethyl-11-azaerythronolide A

To a solution of 10-dihydro-10-deoxo-11-azaerythronolide A (5 g, 11.92 mmol) in ethanol (96%) (50 mL) was added acetaldehyde (7 mL, 120.5 mmol) and palladium on carbon ( 5%) 2.5 g), then the reaction mixture is hydrogenated with stirring at 20 bar for 10 hours. The catalyst is filtered off, washed with ethanol (20 ml) and the combined liquid phases are concentrated by evaporation under reduced pressure to a volume of about 30 ml. Water (100 mL) and CHCl ₃ (50 mL) were added to the reaction mixture, pH was adjusted to 4.5 by addition of 2M HCl, the layers were separated and the aqueous phase was extracted again with chloroform (2 x 50 mL). The chloroform extraction reaction step was repeated after alkalization to pH 8.5 with aqueous sodium hydroxide solution (3 x 50 mL), the combined chloroform extracts were dried over potassium carbonate and evaporated under reduced pressure. 4.65 g (87.2%) of crude 10-dihydro-10-dsoxo-11-ethyl-11-azaerythronolide A are obtained. The obtained product is suspended in diethyl ether (10 ml), stirred at room temperature for 1 hour, filtered. ee, the precipitate was washed with diethyl ether and dried. 3.2 g of a chromatographically homogeneous product are obtained (thin layer chromatography, Rf 0.390). Melting point: 204-206 ° C.

Example 4

10-Dihydro-10-deoxo-11- (n-propyl) -1-azaerythornolide A

To a solution of 10-dihydro-10-donxo-11-azeethronolide A (6 g, 14.30 mmol) in ethanol (96%) (60 mL) was added propionaldehyde (11.4 mL, 157.31 mmol) and palladium on charcoal (5%) (3.0 g), then the reaction mixture is hydrogenated with stirring at 2.2 MPa for 10 hours. The catalyst is filtered off, the filtrate is concentrated by evaporation under reduced pressure to a thick syrup, whereupon the product is isolated by pH gradient extraction. Water (100 mL) and dichloromethane (50 mL) were added to the reaction mixture, the pH was adjusted to 4.5 with 2M HCl, the layers were separated and the aqueous layer was re-extracted with dichloromethane (2 x 50 mL). The aqueous solution was basified with sodium hydroxide solution and the reaction step of extraction with dichloromethane was repeated at pH 8.5 (1 x 150 mL, 2 x 50 mL). The combined organic extracts at pH 8.5 are filtered, the filtrate is concentrated by evaporation under reduced pressure to a suspension density, the precipitated crystals are filtered off, washed with dichloromethane and dried to give a chromatographically homogeneous product (TLC, Rf 0.415). Yield 4.3 g (65.2%). Melting point 212-216 ° C.

Example 5

4-O-Acetyl-10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A

To a solution of 10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A (5 g, 11.53 mmol) in pyridine (30 mL) was added acetic anhydride (30 mL) and the reaction mixture was allowed to stand at room temperature for 2 hours. room temperature. The acylation step is stopped by the addition of ice and the product isolated by extraction with chloroform at pH 9.0 (3 x 50 mL). The combined organic extracts were dried over potassium carbonate and evaporated to give 3.4 g of crude product. The precipitate was suspended in diethyl ether (10 mL), stirred at room temperature for 1 hour, and filtered to give 1.75 g (53.2%) of the title product, mp 187-189 ° C (thin layer chromatography, Rf 0.564).

IR (KBr): 1725 (CaO lactone and ester) and 1235 cm ^- ^ (OAc) 'H-NMR (CD ₃ 0S): 2.343 (s, 3H, N-CH _3), 2.052 (s, 3H, 4- -OAc) and 5.227 ppm (d, 1H, 4-H).

Using the same procedure, except that propionic anhydride is used instead of acetic anhydride, prepare the same. the corresponding 4-O-propionylderivative.

EN 274 497 82

Example 6

4,6,13-Triacetyl-10-dlhydro-10-deoxo-11-methyl-11-azaerythronolide A

To a solution of 10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A (5 g, 11.53 mmol) in pyridine (50 mL) was added acetic anhydride (50 mL) and the reaction mixture was allowed to stand at room temperature for 7 days. rooms. The reaction is quenched by the addition of ice and the product is isolated by chloroform extraction as described in Example 5. The combined organic extracts are dried over potassium carbonate, evaporated to dryness and chromatographed on a silica gel column with CH ₂ Cl ₂ / CH ₃ OH / NH @ 1 H (90: 9: 1.5). Pooling of the fractions of less mobile material, evaporation of the solvent and drying of the obtained amorphous product gave 4,6,13-O-triacetyl derivative, m.p. 180-182 ° C (Rf 0.337).

IR (KBr): 1740 (C = 0, ester), 1715 (CNO, lactone) and 1240 cm ^-1 (OAc) ^X N-NMR (CDC1 _3): 43.1 (q, _N-CH3); 173.5 (s, C = 0 lactone) and 170.2, 170.1 and 169.1 ppm (s,

CnO acetates).

Example 7

11-N, 4,6-O-Triacetyl-10-dihydro-10-deoxo-11-azaerythronolide A

From 10-dihydro-10-deoxo-11-azaerythronolide A (5.0 g, 11.9 mmol) and acotanhydride (50 mL) in pyridine (50 mL), the crude 11-N, 4, 6-O-Triacetyl-10-dihydro-10-deoxo-11-azaerythronolide A. The acetylation reaction is stopped after 24 hours, the product isolated by conventional chloroform extraction methods, and the crude precipitate obtained is slurried in diethyl ether (50 ml). The suspension was stirred for 1 hour at room temperature and filtered to give the insoluble title product. Yield 4.08 g (68.3%). Melting point: 220-223 ° C.

_Rf 0.417

IR (KBr): 1715 (C 11 O, lactone and ester), 1605 (NAc) and 1240 cm ^-1 (OAc), ¹ H-NMR (CD ₃ OD): 2.115 (s, 3H, N-Ac), 2.053 ( s, 3H, 4-OAc) and 2.040 ppm (s, 3H, 6-OAc). Example 8

10-Dihydro-10-deoxo-11-methyl-11-azaerythronolide A hydrochloride

10-Dihydro-10-deoxo-11-methyl-11-azaerythronolide A (4.34 g, 10 mmol) was suspended in 25 mL of water and 0.25N HCl was added dropwise with stirring for 1 hour to adjust the pH to 5 , 8. The clear reaction mixture was stirred for another hour at room temperature, filtered and lyophilized. 4.48 g (95.5%) of 10-dihydro-10-deoxo-11-methyl-11-azaerythronolide A hydrochloride are obtained.

¹ H-NMR (CD ₃ OD): 3.03 ppm (s, 3H, N-CH ₃ ).

Analysis: calculated 7.54% Cl, found 6.97% Cl.

In an analogous manner, but by substituting hydrochloric acid for acetic, sulfuric, phosphoric, citric, benzoic, etc., the corresponding salt of 10-dihydro-10-deoxo-11-alkyl-11-azaerythronolide A and its N- or / a is prepared. N, O-substituted derivatives.

Example 9

10-Oihydro-10-deoxo-11-methyl-11-azaorythornolide A

Carry out the procedure of Example 2 starting from 10-dihydro-10-deoxo-11-azaerythronolide A (1 g, 2.38 mmol), formaldehyde (36%) (0.184 mL, 2.38 mmol) and formic acid. (98-100%) (0.183 mL, 4.77 mmol) and the reaction was performed in acetone (20 mL). This afforded 0.93 g (89.8%) of the title product.

Claims (1)

A process for the preparation of the 10-dihydro-10-deoxo-11-azaerythronolides of the general formula (I) ## STR3 ## wherein the alkyl or alkanoyl group containing from 1 to 4 carbon atoms is in each case 1 to 4; ₂ , R 8 and R 4 are the same or different and are hydrogen or C 1 -C 4 alkanoyl, and optionally their pharmaceutically acceptable acid salts, characterized in that 10-dihydro-10-deoxo-11-azaerythronolide A of the formula III H undergoes reductive alkylation (A) formaldehyde in the presence of formic acid, or Ag) an aliphatic aldehyde of formula IV R ₅ - CHO (IV) wherein R 8 is a C 1 -C 4 alkyl group, in the presence of hydrogen and a noble metal catalyst, and then the substance obtained by the A? Or A _{2 process} is optionally acylated with lower aliphatic acid anhydrides, and optionally converting the obtained products into pharmaceutically acceptable acid salts.