CA1323026C

CA1323026C - Antibacterial 9-deoxo-9a-allyl and propargyl-9a-aza- 9a-homoerythromycin a derivatives

Info

Publication number: CA1323026C
Application number: CA000582491A
Authority: CA
Inventors: Gene M. Bright
Original assignee: Pfizer Corp SRL
Current assignee: Pfizer Corp SRL
Priority date: 1987-11-10
Filing date: 1988-11-08
Publication date: 1993-10-12
Anticipated expiration: 2010-10-12
Also published as: JPH0631301B2; KR900008676B1; YU208788A; ES2053765T3; DE3878835T2; CS272243B2; ZA888364B; MY104109A; DD275871A5; WO1989004167A1; PL275690A1; MX13723A; JPH01153632A; CN1018648B; PT88957A; AU597194B2; IL88280A0; IL88280A; CS740288A2; AU2496888A

Abstract

Abstract Antibacterial 9-deoxo-9a-allyl and propargyl-9a-aza-9a-homoerythromycin A compounds, pharmaceutically acceptable salts thereof, pharmaceutical compositions comprising antibacterially effective amounts thereof and a pharmaceutically acceptable carrier, and the treatment of bacterial infections with antibacterially effective amounts thereof.

Description

~ .

A~TIBACTERIAL 9-DEOXO-9a-ALLYL AND PROPARGYL-9a-AZA-9a-HOMOERYT~ROMYCIN A DERIVATIVES

This invention relates to novel der~vatives of 9-deoxo-9a-aza-9a-homoerythromycin A. More particularly it relates to 9a-allyl and 9a-propargyl derivatives of -~
9-deoxo-9a-aza-9a-homoerythromycin A, to pharmaceutically acceptable acid addition salts thereof and the use of -said compounds as antibacterial agents.
' Erythromycin A is a macrolide antibiotic produced by fermentation and described in U.S. Patent No. ~.

2,653,899. Numerous derivatives of erythromycin A have ~
been prepared in efforts to modify its bioloqical -15 and/or pharmacodynamic properties. Erythromycin A ~
esters with mono- and dicarboxylic acids are reported .
in Antibiotics Annual, 1953-1954, Proc. Symposium ~.
Antibiotics (Washington, D.C.), pages 500-513 and .
514-521, respectively. U.S. Patent ~o. 3,417,077 describes the cyclic carbonate ester of er~thromycin A, the reaction product of erythromycin A and ethylene :
carbonate, as an active antibacterial agent.
U.S. Patent 4,328,334, issued May 4, 1982 .
describes 9-deoxo-9a-aza-9a-homoerythromycin A and :~
25 refers to it by the name 11-aza-10-deoxo-10-d.ihydro-er~thromycin A. Since said compound is a ring expanded (homo) derivative of erythromycin A, nitrogen taza) being the additional atom Oc the ring system, the nomen-clature 9-deoxo-9a-aza-9a-homoerythromycin A is pre-ferred for the parent rin~ system of the compounds of this invention.

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selgian Patent 892,351, published July 1, 1982, and its British counterpart, Application 2,094,293A, published September 15, 1982, disclose the N-methyl derivative of 9-deoxo-9a-aza-9a-homoerythromycin A, while U.S. Patent 4,526,889 claims the corresponding 4~-epi-9a-methyl isomer. U.S. Patent 4,512,982 claims 9-deoxo-9a-methyl-9a-aza-9a-homoerythromycin A
derivatives wherein the substituent at the 4~ can be hydrogen or amino. -~
U.S. Patent 4,382,085, issued May 3, 1933 describes 4n-epi erythromycin A: i.e., the 4"-OH group has the axial configuration. The 4"-OH in e~ythromycin A has the equatorial configuration.
9-Deoxo-9a-propargvi-9a-aza-9a-homoerythromycin A
was disclosed in the Abstract of 27th Interscience Conference on Antimicrobial Agents and Chemotherapy ~October, 1987) as an HPLC standard in tissue analysis o azithromycin and analogs thereof.

It has now been found that 9a-allyl and 9a-propargyl derivatives of 9-deoxo-9a-aza-9a-homoervthromycin A are effective antibacterial agents against Gram-positive and Gram-negative bacteria. The compounds have the formula (I) IO, N(CE~3)2 ~' ;~~

'OCH3 (I) wherein R is allyl or propargyl.

Also included in this invention, and useful for the same purpose as formula (I) compounds, are the pharmaceutically acceptable acid addition salts thereof.
Included among said salts, but by no means limited to 3aid salts, are those enumerated below: hydrochloride, hydrobromide, sulfate, phosphate, formate, acetate, propionate, butyrate, citrate, glycolate, lactate, tartrate, malate, maleate, fumarate, gluconate, stearate, mandelate, pamoate, benzoate, succinate, lactate, p-toluenesulfonate and asparate.
Also included as part of the present invention is a method for treating a bacterial infection in a mammal which comprises administering to said mammal an anti-bacterially effective amount of a compound of 15 formula (I), and a pharmaceutical composition in unit ;
dosage form for treating a bacterial infection which comprises an antibacterially effective amount of a compound of for~ula (Il and a pharmaceutically acceptable carrier or diluent. Additionally, compounds of formula (I) exhibit significant activity against Nei~seria qonorrhea and HaemoPhilus in vitro and against many Gram-positive and Gram-negative microorganisms ln vivo. In their use'ul oral activity and unexpectedly ;
long serum half-life in mammals, the formula (I) com-pounds are like 9-deoxo-9a-methyl-9a-aza-9a-homoerythro-mycin A, and quite unli~e the correspondir.g 9a-desmethyl compound 9-deoxo-9a-aza-9a-homoerythromycin A which exhibits no practical oral activity in vivo, and a substantially shorter serum half-life.

, --- 132302~

The compounds of formula ~I) wherein R is as previously defined are prepared according to the following scheme:
Q
~` HO N(CH3)2 :. .

~ ~ 1. R'CH2Hal HO ~ ~ 2. 03P ~ (I) ~.
' ~l~o",ro~ , -~'/OH
/ 'OCH3 wherein R' is CH- C- or CH2zCH- and Hal is a halogen, preferably bromo.
The reaction comprises the initial alkylation of ~:
the corresponding 9-deoxo-9a-aza-9a-hydroxy-9a-homo-erythromycin A, 3'-N-oxide with an allyl or propargyl halide, preferably bromide. In practice the reaction ;
is carried out in a water-free reaction-inert solvent, `~
pre~erably chloroform, at ambient temperatures.
Other solvents, including halogenated hydrocarbons, esters, ethers or aromatic solvents, can be employed with equally good results. In addition, the temperature can be lowered or elevated without changing ~he course of the reaction, and will result in 3 slowing or accelerating of the reaction course, respectively.

~ ...... . .. . .
',, ~' ' ' ' :,' '' 'D .. :, ' ' . ' ' ' ; ' . ' -The by-product of the alkylation, a hydrogen halide, is removed by the addition of a large excess of an inorganic base such as potassium carbonate, sodium carbonate, calcium carbonate and the like. In general, a four-fold molar excess base is adequate.
At ambie~t temperatures the reaction is complete in about 18-24 hours. As mentioned previously, this reaction time is a function of reaction temperature and can be adjusted accordingly.
The next step in providing the compounds of the present invention comprises deoxygenation of the 3'-N-oxide. Generally, the purity of the alkylated N-oxide is suf'iciently good to allow its use directly in the next deoxygenation step; if further purification is required, the alkylated N-oxide can be passed through a silica gel column.
The deoxygenation step is carried out with an equimolar amount of triphenylphosphine plus a small excess. The reaction is conducted in a water-free reaction-inert solvent such as those employed for the alkylation reaction. The preferred solvent is tetra-hydrofuran.
The reaction time can vary according to the reflux temperature of the reaction solvent. When refluxing tetrahydrofuran is employed, the reaction is complete in about 4-5 hours.
The product is isolated by removing the solvent and extracting the basic product from unwanted non-basic impurities by partitioning the residue between a water-immiscible solvent and water adjusted to a pH of about4.5. The aqueous layer containing the product is then made basic (pH 10) and the product, as the free base, extracted with a solvent such as ethyl acetate. Further purification can be achieved by normal methods such as recrystallization or chromatography.

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Acid addition salts of the compounds of this inven-tion are readily prepared by treating compounds having formula (I) with at least an equimolar amount of the appropriate acid in a reaction-inert solvent or, in the S case of the hydrochloride salts, with pyridinium hydro-chloride. Since more than one basic group is present in a compound of formula (I), the addition of sufficient acid to satisfy each basic group permits formation of polyacid addition salts. The acid addition salts are recovered by filtration if they are insoluble in the reaction-inert solvent, bv precipitation by addition of a non-solvent for the acid addition salt, or by evapora-tion of the solvent.
A variety of Gram-positive microorganisms and certain Gram-negative microorganisms, such as those of spherical or ellipsoidal shape (cocci), are suceptible to compounds of formula (I). Their in vitro activity is readily demonstrated by ln vitro tests against various microorganisms in a brain-heart infusion medium by the usual two-fold serial dilution technique. Their in vitro activity renders them useful for topical applica-tion in the form of ointments, creams and the like, for sterilization purposes, e.g. sick room utensils; and as industrial antimicrobials, for example, in water treat-ment, slime control, paint and wood preservation.
For in vitro use, e.g. for topica, application, itwill often be convenient to compound the selected product by methods well known in the pharmacist's art into lotions, salves, ointments t creams, gels or the like.
For such purposes, it will generally be acceptable to employ concentrations of active ingredient of from about 0.01 percent up to about 10 percent by weight based on total composition. The dosage form is applied at the site of infection ad libitum, generally at least once a day.

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: 132302~l3 Additionally, formula (I) c~mpounds of this inven-tion are active versus Gram-positive and certain Gram-negative microorganisms in ViVO via the oral and/or parenteral routes of administration in animals, includ- -5 ing man. Their in vivo activity is more limited as ~-_ regards susceptible or~anisms and is determined by the usual procedure which comprises infecting mice of i~
substantially uniform weight with the test organism and subsequently treating them orally or subcutaneously with the test compound. In practice, the mice, e.g.
10, are given an intraperitoneal inoculation of suitably diluted cultures containing approxima~ely 1 to 10 times the LDloo (the lowest concentration of organisms required to produce 100~ deaths). Control tests are simultan-eously run in which mice receive inoculum of lowerdilutions as a check on possible variation in virulence of the test organism. The test compound is administered 0.5 hour post-inoculation, and is repeated 4, 24 anc 48 hours later. Surviving mice are held for 4 days after the last treatment and the number of survivors is noted.
When used in vivo, these novel compounds can be administered orally or parenterally, e.g. by subcutaneous or intramuscular injection, at a dosage of from abo~t 1 mg/kg to about 200 mg/kg of body weight per day. ~he favored dosage range is from about 5 ~.g/kg to about 100 mg/kg of body weight per day and the preferred range from about 5 mg/kg to about 50 mg/kg of body weight per day. Vehicles suitable for parenteral injec-tion may be either aqueous such as water; isotonic saline, isotonic dextrose, Ringer's solution or non-aqueous such as fatty oils of vegetable origin (cotton ~eed, peanut oil, corn, sesame), dimethylsulfoxide and other non-aqueous vehicles which will not interfere with therapeutic efficiency of the preparation and are .' '-:,, ' "
": . . : ,. .
, ,, ~ , -- 1323~2~

non-toxic in the volume or proportion used (glycerol, propylene glycol, sorbitol). Additionally, compositions suitable for extemporaneous preparation of solutions prior to administration may advantageously be made.
Such compositions may include liquid diluents; for example, propylene glycol, diethyl carbonate, glycerol, sorbitol, etc.; buffering agents, hyaluronidase, local anesthetics and inorganic salts to afford desirable pharmacological properties. These compounds may also be combined with various pharmaceutically acceptable inert carriers including solid diluents, aqueous vehicles, non-toxic organic solvents in the form of capsules, tablets, lozenges, troches, dry mixes, suspensions, solutions, elixirs and parenteral solutions or suspen-sions. In general, the compounds are used in variousdosage forms at concentration levels ranging from about 0.5 percent to about 90 percent by weight of the total composition.

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~ 32~02.~

9-Deoxo-9a-aza-9a-hydroxy-9a-homoervthromvcin A 3'-N-oxide To a solution of 9-deoxo-9a-aza-9a-homoerythro-mycin A (U.S. Patent 4,328,334) ~10 g, 13.6 mmol) in 40 ml of methanol, a total of 50 ml of 30% a~ueous hydrogen peroxide (0.58 mol) was added dropwise while stirring over a 10 minute period. After stirring overnight at ambient temperature, the reaction mixture was poured -~
onto a stirred slurry of ice (200 g), ethyl acetate ~200 ml) and water (100 ml). Excess hydrogen peroxide was quenched by cautious dropwise addition of saturated aqueous sodium sulfite until a negative starch-iodine test was indicated. The layers were separated, and the aqueous layer was extracted twice with 200 ml portions of ethyl acetate. The three organic ext_acts were combined, dried (anhydrous sodium sulfate), and concen-trated in vacuo to afford 2 as a colorless amorphous solid (8.6 g, 82% yield).
TLC Rf = 0.20 [methylene chloride-methanol-concen-trated ammonium hydroxide = 6:1:0.1 (in volume);
H-NMR~60 MHz, CDC13)delta 3.21 [6H, s (CH3)2N-O], 3.39 (3H, s, 3"-OCH3): MS m/z 576.3654 (M - C8~1~O4N, C29H54oloN)~ 418-2744 (M - Cl6H30o7~ c2lH4oo7N) 9-Deoxo-9a-aza-9a-allvl-9a-homoerythromycin A
To a well-stirred mixture of 4.0 g (5.2 mmol) of the product of Example 1 in 50 ml Oc chloroform and 2& g (0.20 mol) of su~ipended anhvdrous potassium carbonate, 25 g (17.9 ml, 0.21 mol) of allyl bromide in 10 ml of chloroform was added dropwise over 5 minutes.
Ambient temperature stirring was continued for 18 hours. Chromatography [200 g silica gel, 230-400 mesh, elution with chloroform-isopropanol-concentrated ammonium hydroxide = 8:2:0.1 (in volume)] afforded 0.72 g (colorless foam) of alkylated substrate, ,, ;
" ~.
.

.: . . . ~ . ... . .
- . ., . ~ . : - .
- . - - :. : . . :

- ~32302~

sufficiently pure for the next ~deoxygenation) step.
~he entire sample was combined with 0.93 g (3.6 mmol) of triphenylphosphine in 21 ml of tetrahydrofuran, and the resulting mixture was refluxed for 4 hours. Solvent removal ~n vacuo afforded an oily residue which was dissolved in 150 ml of ethyl acetate. An equal volume of water was added the the pH was adjusted to 4.5 ~6N
hydrochloric acid). The separated aqueous phase was extracted with several 150 ml portions of ethyl acetate.
Finally, the aqueous phase was combir.ed with an equal volume of ethyl acetate, and the pH was elevated to 10.0 (10~ potassium carbonate). The phases were separated, and the aqueous was extracted twice with 100 ml of ethyl acetate. The combined final (3) ethyl acetate extracts were dried (sodium sulfate) and concen-trated in vacuo to an amber foam (0.55 g). Flash chroma-tography 150 ~ silica gel, 230-400 mesh, elution with chloroform-isopropanol-concentrated ammonium hydroxide ~ 15:1:0.1 (in volume)l afforded 408 mg ~10% yield) of 3b as a colorless amorphous solid.
TLC Rf ~ 0.36 [methylene chloride-methanol-concen-trated ammonium hydroxide = 9:1:0.1 (in volume)];
3C-NMR (100 MHz, CDC13)delta 177.8, 136.3 and 117.1 (olefinic carbons), 103.0, 95.2, 83.9, 78.5, 78.0, 77.9, 77.~, 74.8, 74.2, ~2.8, 70.9, 68.8, 65.6, 64.3, 64.2, 61.2, 53.6, 49.4, 45.0, 41.9, 41.2, 40.3 (2), ;
35.0, 29.0, 27.8, 26.8, 22.0, 21.6, 21.5, 21.3, 18.3, 16.5, 15.0, 11.3, 9.7, 9.6; MS m/z 774.9 (M, C40H 4O12N2), 616.4 (M - C8H16O2N), 599.4 (M C8H17 3 C 6H30O5N)~ 442 (M - C16H30O6N), 157.9 (M - C32H58OloN)--- 132302i~

9-Deoxo-9a-aza-9a-propar~vl-9a-homoerythromvcin A
To a well-stirred mixture of 10.0 g (13.0 mmol) of the product of Example 1 in 75 ml of chloroform and 5 72 g (0.52 mol) suspended anhydrous potassium carbonate, `
62 g (0.52 mol) of propargyl bromide was added dropwise over 15 minutes. Ambient temperature stirring was continued for 18 hours. The reaction mixture was filtered and concentrated in vacuo to a foam (8.5 g).
.10 The entire sample was dissolved in 75 ml of anhydrous THF. Triphenylphosphine ~10.5 g, 0.04 mol) was added, and the mixture refluxed for 2 hours. Solvent was removed in vacuo, and the crude product was dissolved in 100 ml of ethyl acetate, which was then layered with an equal volume of water. The pH was adjusted to 4.0 ~6N hydrochloric acid). The separated aqueous layer was then stirred with 100 ml of fresh ethyl acetate while the pH was adjusted to 10.0 (6N sodium hydroxide solution). Concentration in vacuo of the organic layer afforded 7.3 g of semi-purified product. Chromatography of the entire sample on silica gel ~430 g, 230-400 mesh, elution with chloroform-methanol-concentrated ammonium hydroxide = 15:1:0.1 (in volume)] afforded 1.67 g (17~) of purified ~roduct as a colorless amorphous solid.
TLC Rf = 0.39 [methylene chloride-methanol-concen-trated ammonium hydroxide = 9:1:0.1 (in volume)~;
3C-NMR (100 MHz, CDC13)delta 178.0, 102.8, 94.7, 83.4, 80.0, 78.0, 77.7, 77.5, 77.2, 74.8, 73.9 (2), 72.9, 70.8, 68.8, 65.6, 65.5, 63.4, 61.2, 49.4, 44.9, 43.1, 42,2, 40.3 (2), 37.3, 34.8, 28.8, 26.7, 26.4, 21.9, 21.6, 21.3 (2), 18.2, 16,7, 14.4, 11.1, 10.7, 9.S; MS
m/z 772-9 ~M~ C40H7212N2)' 614-4 (M C8H16 2 M - C8H17O3N)~ 456.2 (M C16H30 5 16 30O6N)~ 158-0 (M - C32Hs6O1ON)-.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A compound of the formula:

(I) (wherein R is allyl or propargyl) or a pharmaceutically acceptable acid addition salt thereof.

2. The compound or salt of claim 1, wherein R is allyl.

3. The compound or salt of claim 1, wherein R is propargyl.

4. A pharmaceutical composition in unit dosage form or treating a bacterial infection which comprises an antibacterially effective amount of the compound or salt according to claim 1 and a pharmaceutically acceptable carrier or diluent.

5. The composition of claim 4, which contains the compound or salt in an amount of 5 to 50 mg/kg of body weight per day.

6. Use of the compound or salt as defined in claim 1 for treating a bacterial infection in a mammal.

7. A process for producing the compound as defined in claim 1, which comprises:
(i) reacting 9-deoxo-9a-aza-9a-hydroxy-9a-homoerythromycin A 3'-N-oxide with an allyl or propargyl halide in a water-free reaction-inert solvent, thereby preparing an intermediate corresponding to the compound of claim 1 but the N atom of the N(CH3)2 group is in the N-oxide form, and (ii) deoxygenation of the N-oxide.

8. The process of claim 7, wherein the allyl or propargyl halide is allyl or propargyl bromide;
the solvent is a halogenated hydrocarbon solvent;
the reaction of step (i) is conducted at an ambient temperature; and the deoxygenation is conducted with an equimolar amount of triphenylphosphine plus a small excess.