DK145578B - METHOD OF ANALOGY FOR THE PREPARATION OF CHLOROMETYL-17ALFA-ACETOXY-9ALFA-FLUOR-11BETA-HYDROXY-16BETA-METHYL-3-OXOANDROSTA-1,4-DIENE-17BETA CARBOXYLATE - Google Patents

Description

145578

The present invention relates to an analogous method for the preparation of a novel anti-inflammatory active steroid of the androstane series, namely chloromethyl-17o-acetoxy-9a-fluoro-11B-hydroxy-16B-methyl-3-oxoandrosta-1,4-diene-17B-carboxylate with the formula shown in the preamble of claim 1.

British Patent Specification No. 1,438,940 and Danish Patent Specifications Nos. 132,894 and 133,159 disclose antiinflammatory steroids of the general formula 145578 20 0-R4 1 CO 3 R X '-.- OCOR'3 where X is a hydrogen compound. , chlorine or fluorine atom; R 2 is a 3-hydroxy group, an oxo group or, if X is a chlorine atom, a 2 β-chlorine atom; R is a hydrogen atom, a methylene group or a 3 4

a- or 3-methyl group; R is H or an alkyl group; R

Among other things, may be a fluoromethyl, chloromethyl, bromomethyl or iodomethyl group or a fluoroethyl group; and - denotes a single bond or double bond.

It has now been found that the aforementioned compound, which is within the scope of Formula I, has particularly advantageous properties in comparison with the close analogs thereto, which are specifically described in the aforementioned patents.

Chloromethyl-17α-acetoxy-9α-fluoro-11β-hydroxy-16B-methyl-3-oxoandrosta-1,4-diene-173-carboxylate has particularly high human topical anti-inflammatory activity as measured by McKenzie's spot test (a topical sample of vessel contraction), and combined with relatively weak systemic activity, for example, as measured by the reduction in thymus weight in mice. The compound hereby has a significantly better therapeutic index than the compounds known from the above-mentioned patents, as will be seen from the following Table 1. When applied locally to the skin of mice, it exhibits a good ratio of anti-inflammatory activity as measured by the reduction of croton oil-induced edema. on the one hand, and undesirable systemic activity as measured by the depression of the hypothalamic-pituitary-adrenal axis, on the other.

These results show that the subject compound is valuable for the local treatment of inflammation in humans and animals with minimal tendency to cause unwanted systemic side effects.

In Table 1, the topical anti-inflammatory effect, systemic effect and calculated therapeutic values of the present compound are compared with, in part, a number exemplified in DK patent 133,158 and partly the best of the compounds exemplified in DK patent 133,894.

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The process according to the invention for preparing the above compound is characterized by the characterizing part of claim 1. Thus, the corresponding 17α-acetoxy-androstan-176-carboxylic acid or functional derivative thereof can be esterified, or chloromethyl-17α-hydroxy-androstan-176-carboxylate to give the compound 17α-acetoxy-9α-fluoro-116-hydroxy-methyl 3-oxo-androsta-l, 4-diene-176-carboxylate. Particularly advantageous embodiments of the invention are set forth in claims 2 and 3, respectively.

Thus, the subject compound can be prepared by reacting a salt of the corresponding 17a-acetoxy-176-carboxylic acid parent compound with a compound of the general formula C1-6 Y where Y is a fluorine-different halogen atom, preferably bromine or iodine. The preferred halogen compound is iodine chloromethane.

The reaction just described is advantageously carried out using a salt of the parent 173-carboxylic acid and an alkali metal salt, e.g. in particular a dipolar aprotic solvent such as an amide solvent such as dimethylformamide, dimethylacetamide or hexamethylphosphoramide, or sulfoxide solvent such as dimethylsulfoxide, and suitably at a temperature in the range of 15-100 ° C.

For the preparation of the indicated compound, it is also advantageous to subject a corresponding iodomethyl or bromomethyl 17B carboxylate to a halogen exchange reaction which serves to replace the halogen substituent in the halogen methyl group with chlorine. Thus, according to the invention, the compound can be prepared from the corresponding iodomethyl ester bromomethyl-176-carboxylate compound by reaction with an alkali metal, alkaline earth metal or ammonium chloride, for example lithium chloride. The reaction is advantageously carried out in a solvent containing, for example, acetone, methyl ethyl ketone, dimethylformamide, dimethylacetamide, hexamethylphosphoramide or ethanol.

6a-Acetoxy-17e-carboxylic acid is prepared by the process described in GB-PS 1,384,372, which is illustrated below in the detailed description of the preparation of intermediates.

The parent 17 α-hydroxy-17 3-carboxylate corresponding to the desired compound may also be subjected to esterification of the 17α-hydroxyl group, and the 17α-hydroxy-173-carboxylate may be prepared, for example, by esterification of the corresponding 17α-hydroxy-173. -carboxylic acid by the methods set forth above.

The purification of the 17α-hydroxy group in the preparation of the present novel androstane compound may, if desired, be carried out by conventional techniques, for example, by reacting the parent 17α-hydroxy compound with a mixed anhydride of acetic acid, for example, which can be developed in situ by reacting acetic acid with a suitable anhydride such as trifluoroacetic anhydride, preferably in the presence of an acidic catalyst such as, for example, p-toluenesulfonic acid or sulfosalicylic acid. It is also possible to develop the mixed anhydride in situ by reacting acetic anhydride with a suitable additional acid, for example trifluoroacetic acid.

The esterification reaction is advantageously carried out in an organic solvent such as benzene, methylene chloride or excess of the carboxylic acid used to form the mixed anhydride, and the reaction is conveniently carried out at a temperature of 20-100 ° C.

The 17α-hydroxy group may also be esterified by reacting the parent 17α-hydroxy compound with acetic anhydride or acetyl chloride, optionally in the presence of non-hydroxylic solvents such as chloroform, methylene chloride or benzene and preferably in the presence of a strong acid catalyst such as perchloric acid or or a highly acidic cation exchange resin, for example "Amberlite" ® IR 120, the reaction being conveniently carried out at a temperature of 25-100 ° C.

To prepare the 17α-ester of the 173-carboxylic acid which can be used to prepare the subject compound, it is preferred to treat the parent 17α-hydroxy-17β-carboxylic acid with acetic anhydride, optionally in the presence of a base such as potassium carbonate. This reaction is conveniently carried out at elevated temperature. Optionally mixed anhydride can be solvated under acidic conditions (e.g. with aqueous acetic acid) or basic conditions (e.g. with aqueous pyridine or diethylamine / acetone). It is also possible to treat the parent 17α-hydroxy-17β-carboxylic acid with acetyl chloride, preferably in a solvent such as a halogenated hydrocarbon such as methylene chloride, and advantageously in the presence of a base such as triethylamine, preferably at low temperature, e.g. ° C.

The subject compound may be recast into pharmaceutical and veterinary pharmaceutical compositions for use in anti-inflammatory therapy with one or more pharmaceutical carriers or excipients. It is particularly preferred to prepare compositions which are suitable for topical application, namely because of the high topical activity of the compound.

The amount of the active androstane compound in the topical compositions thereof depends on the exact type of preparation to be prepared, but will generally be in the range of 0.001 to 5% by weight. However, for most types of compositions, it is generally true that the amount used will advantageously be in the range of 0.005 to 0.5%, preferably 0.01 to 0.25%. Advantageously, in powders for inhalation or inhalation, the amount of the androstane compound may be in the range 0.1 to 2%.

Aerosol preparations are preferably so adapted that any metered dose or "breath" from the aerosol container contains 25-200 µg, preferably approx. 50 µg of the present androstane compound. The administration can be done several times daily, eg 2, 3 beers 4 times and with 1, 2 or 3 doses each time. The total daily dose with an aerosol will be in the range of 100-2000 µg, preferably 200-800 µg.

145578 8

Some examples serve to illustrate the process of the invention. Prior to the Examples, some examples of the preparation of intermediates are used which are used in the Examples. In both, organic extracts are dried over magnesium sulfate.

Intermediate 17α-Ac ethoxy-9α-fluoro-11β-hydroxy-16β-methyl-3-oxoandrosta-1,4-diene-17β-carboxylic acid

A suspension of 5.0 g of 9α-fluoro-113,17α-dihydroxy-160-methyl-3-oxoandrosta-1,4-diene-17 (3-carboxylic acid and 2.11 g of potassium carbonate in 20 ml of acetone was stirred and treated with 19.4 ml of acetic anhydride, then the mixture was heated under reflux for 2 hours, after cooling the mixture was treated with 63 ml of water and acidified with 3 ml of concentrated hydrochloric acid with stirring at about 0 ° C for 1 hour. was dried in vacuo at 50 ° C overnight, then suspended in 114 ml of acetone and treated with 4.8 ml of diethylamine.

After 30 minutes, volatile material was removed under reduced pressure and the residue treated with 107 ml of water? 600 ml of ethyl acetate was added and the mixture was acidified to pH 1 with 2N hydrochloric acid. The aqueous phase was separated and further extracted with ethyl acetate, then the combined ethyl acetate phases were washed well with water, dried and concentrated to a small volume. The solid was collected, washed with ethyl acetate and dried in vacuo at 60 ° C for 2 days; thereby gaining the title compound as colorless crystals in an amount of 4.916 g; Amax (ethanol) 239.5 nm = 337),

A portion of 1.01 g of the title acid in 5 ml of methanol was converted with 1.3 ml of 2M methanolic sodium hydroxide to 976 mg of the sodium salt precipitated with ether.

Intermediate 2

Tetra-n-butylammonium salt and. cesium salt of 17ct-acetoxy-9a-fluoro-11g-hydroxy-16g-methyl-3-oxoandrosta-1,4-diene-173-carboxylic acid.

A) Tetra-n-butylammonium salt

A suspension of 2,102 g of the title androstan-178-carboxylic acid in 10 ml of chloroform was mixed with a solution of 1,702 g of tetra-n-butylammonium hydrogen sulfate and 394 ml of sodium hydroxide in 10 ml of water and stirred for 30 minutes. The organic layer containing tetra-n-butylammonium androstane-17β-carboxylate was separated and used directly.

b) Cesium salt

A solution of 944 mg of the androstan-17β-carboxylic acid in 20 ml of methanol was stirred and treated with 3.7 ml of aqueous 20% cesium carbonate to give a slightly cloudy solution of pH7. It was evaporated to dryness and the residue was evaporated twice from methanol, then dried overnight in vacuo to give 1.592 g of the cesium salt as a foam;

Wax 241 ™ <E «m = 196> ·

Intermediate 3

Chloromethyl-9a-fluoro-113,17g-dihydroxy-163-methyl-3-oxoandrosta-1,4-diene-17-carboxylate.

A mixture of 400 mg of sodium 9 <x-fluoro-113,17a-dihydroxy-16β-methyl-3-oxoandrosta-1,4-diene-17β-carboxylate and 0.36 ml of chloroiodomethane in 1.3 ml hexamethylphosphoramide was stirred at room temperature for 3 1/3 hours. The solution was diluted with ethyl acetate and washed successively 3 times with water, 1 time with sodium bicarbonate and water to pH 5.6, then dried and evaporated to give 443 mg of a yellow solid.

It was triturated with ethyl acetate / ether and then 2 times with ether, and the resulting liquids were evaporated to 230 mg of a foam which was subjected to preparative layer chromatography on silicic anhydride in chloroform / acetone 40: 1 (four runs) to give 162 mg of colorless foam. . Two acetone / ether crystallizations gave 37 mg of the title chloromethyl ester with m.p. 174-178 ° C (decomposition; Copper), λ (ethanol) 237.5 nm (ε = 15400). The mother liquor was collected and evaporated and the residue was crystallized twice from aqueous methanol to give a further yield.

69 mg and with m.p. 174-178 ° C (dec.; Kofler).

145578 ίο

Intermediate 4

Lodomethyl-17a-acetoxy-9a-fluoro-113-hydroxy-163-methyl-3-oxo-androsta-1,4-diene-173-carboxylate.

A solution of 1.056 g of chloromethyl-17α-acetoxy-9α-fluoro-113-hydroxy-163-methyl-3-oxoandrosta-1,4-diene-173-carboxylate and 3,774 g of sodium iodide in 30 ml of acetone was stirred and heated to reflux in 1 1/2 hours. The mixture was evaporated, dissolved in ethyl acetate and then washed with water, aqueous 10% sodium thiosulfate, water, 5% rs sodium bicarbonate, water and brine, and dried and evaporated to a yellow foam in an amount of 1.277 g.

The product was isolated after preparative layer chromatography (chloroform / acetone 20: 1, three passages) as 951 mg of a foam and the foam was crystallized twice from acetone to give the title iodirethyl ester as light yellow crystals in an amount of 677 mg; mp. 174-176 ° C,? 22 = 18.6 ° (c = 1.10 in dioxane).

Intermediate 5

Bromomethyl 17α-acetoxy-9 g-fluoro-β-hydroxy-1,6 3-methyl-3-oxo-androsta-1,4-diene-173-carboxylate.

A suspension of 250 mg sodium 17α-acetoxy-9α-fluoro-113-hydroxy-163-methyl-3-oxoandrosta-1,4-diene-17 (3-carboxylate in 7.5 mL hexamethylphosphoramide was stirred with 4.0 mL The solid had disappeared after about 15 minutes and the reaction was almost complete after 5 hours as evidenced by thin layer chromatography (silicic anhydride, chloroform / acetone 4: 1). After 5 1/2 hours the mixture was diluted with 5% sodium bicarbonate and extracted with ethyl acetate; the combined extracts were washed with water, dried and evaporated in vacuo to 291 mg of a foam Preparative layer chromatography (silicic anhydride, chloroform / acetone 4: 1, three runs) gave the least polar, quantitatively smaller product as crystals in an amount of 70 mg; two recrystallizations from acetone gave the title bromomethyl 17α-acetoxyandrostan-173 ~ carboxylate as 42 mg colorless crystals, mp 199-200 ° C (decomposition; Kofler), a2® = 25 ° ( c = 0.51 dioxane); by thin layer chromatography on silicic anhydride (chloroform, eight passages) and at 1 H nmr the product was found to be approx. 90% pure.

U5578

IX

Examples 1-6 illustrate the preparation of chloromethyl-17α-acetoxy-9α-fluoro-113-hydroxy-163-methyl-3-oxoandrosta-1,4-diene-17β-carboxylate.

Example 1 a) 976 mg of sodium 17α-acetoxy-9α-fluoro-11β-hydroxy-160-methyl-3-oxoandrosta-1,4-diene-173-carboxylate were treated in 5 ml of hexamethylphosphoramide with 0.8 ml of chloroiodomethane for 19 hours. hours and then with 0.8 ml of additional reagent for an additional 4 1/2 hours. The mixture was diluted with ethyl acetate and ether and washed with water, 5% sodium bicarbonate solution, sodium thiosulfate and water and dried and evaporated to give 664 mg of a non-acidic fraction. Recrystallization from acetone afforded colorless crystals of the desired chloromethyl ester in an amount of 472 mg. A portion of 170 mg thereof, after recrystallization from acetone, gave a test sample of 144 mg; aD = 32.7 ° (dioxane, c = 0.308), λ (ethanol) 239nm (e = 15100).

mdx b) the sodium salt, cesium salt and tetra-n-butylammonium salt of 17α-acetoxy-9α-fluoro-11β-hydroxy-16β-methyl-3-oxoro · androsta-1,4-diene-17β-carboxylic acid were treated on in a similar manner as described under (a) with chloro iodomethane, the solvents and reaction time being given in the table below. In the experiment using the sodium salt, lithium chloride was added after the reaction. The amount of the desired chloro methyl ester present in the reaction mixture was assessed by HPLC or TLC as indicated in the table.

145578 12

Table 2 17β Carboxyl Solution CICHICH I, Time LiCl, Yield Yield as a salt as a mole of moles of hours moles of the raw material equiv. product desired spring added weight% compound x reaction% ____tion____ sodium (Μβ2Ν) ^ PO 2.0 1.5 3 105 80

Me2SO 2.1 23.5 3 91.5 68 "Me2N.COCH3 2.1 23.5 3 94 61" Me2N.CHO 2.1 23.5 3 88 60 Cesium (Me2N) 3PO 2.0 5 - 96 ( th) ~ 90Δ "Me2NCHO 2.0 33.5 - 115 ^ 75Δ

Buji CHCl3 2.7 69 - 106 * 30Δ x) rated at h.p.l.c. or where indicated (Δ), by t.l.c. (approximate) for detectable impurities by ultraviolet absorption and fluorescence quenching, respectively (254nm).

Example 2

A mixture of 50 mg of iodomethyl-17α-acetoxy-9α-fluoro-113-hydroxy-163-methyl-3-oxoandrosta-1,4-diene-173-carboxylate and 38 mg of lithium chloride in 0.5 ml of hexamethylphosphoramide was stirred at room temperature for 1 hour. 1 hour. The resulting pale yellow solution was found to contain the desired chloromethyl ester by comparison with an authentic sample by thin layer chromatography on silica anhydride in chloroform / acetone (10: 1, two passages); none of the starting iodine methyl ester was left.

Example 3 1 mg of Chloromethyl 9α-fluoro-β, 17α-dihydroxy-163-methyl-3-oxoandrosta-1,4-diene-17β-carboxylate was treated with a 0.1 ml aliquot of a mixture prepared from 1 ml glacial acetic acid, 0.2 ml trifluoroacetic anhydride and 0.025 ml of a solution of anhydrous toluene-p-sulfonic acid in chloroform (concentration about 80 mg / ml); the steroid reaction mixture was then heated to 78-80 ° C for 23 minutes. The resulting solution was cooled and treated with 0.5 ml of 2N sodium carbonate solution and then extracted with 3 x 0.3 ml of ethyl acetate; the combined extracts were evaporated under a stream of nitrogen and the residue was dissolved in chloroform for examination by silica gel chromatography on silicic anhydride. There was no residue of the starting steroid, and the main product was shown to be identical to an authentic sample of the desired chloromethyl-17a-acetoxyandrostan-17β-carboxylate. on silica in two solvents (chloroform / acetone 4: 1 and ethyl acetate / petroleum ether (bp 40-60 ° C) 1: 1).

Example 4

A suspension of 250 mg of sodium 17α-acetoxy-9α-fluoro-113-hydroxy-163-methyl-3-oxyandrosta-1,4-diene-173-carboxylate in 7.5 ml of hexamethylphosphoramide was stirred with 3.64 ml of chlorobrpm. methane. -The solid had dissolved. after 15 minutes and tl.c. study (silica, chloroform / acetone 4: 1) after 11/2 hours showed that almost complete reaction to form a single main product equipolar with an authentic sample of the desired chloromethyl ester. After 3 1/4 hours, the reaction mixture was diluted with 20 ml of ethyl acetate and 10 ml of 5% sodium bicarbonate solution; the aqueous phase was further extracted with 2 x 20 ml of ethyl acetate and the combined extracts washed with 3 x 20 ml of water, dried and evaporated in vacuo to a colorless crystalline solid in an amount of 255 mg; by the proton magnetic resonance spectrum in deuteriochloroform, this solid was found to be the desired chloromethyl ester solvated by ca. 1/3 mol of hexamethylphosphoramide.

Example 5

A suspension of 250 mg of sodium 17α-acetoxy-9α-fluoro-113-hydroxy-16β-methyl-3-oxoandrosta-1,4-diene-173-carboxy} in 7.5 mL of hexamethylphosphoric acid and 3.59 mL dichloromethane was stirred at room temperature. After 5 minutes, a clear solution appeared; after 16 hours, t.l.c. on silica in chloroform /, acetone 4: 1 approx. 50% conversion into a mixture of two products in approximately equal amounts; one of these products was identical to the desired chloromethyl ester.

Example 6 5 mg of Bromine Ty 1-17 α-Acetoxy-9 of Luoro-1β-hydroxy-16β-methyl-3-oxoandrosta-1,4-diene-17β-carboxylate and 4 mg of lithium chloride in 0.05 ml of hexamethylphosphoramide were stirred. together for 64 hours at room temperature. Thin layer chromatography on silica in chloroform (five runs) showed that there was no residue of the starting bromomethyl ester and that the entire amount thereof had been converted to the desired chloromethyl ester, which was shown by comparison with an authentic sample.