US3681441A - Quaternary fluorinated ammonium salts - Google Patents

Abstract

The disclosed quaternary ammonium salts contain a hydrofluoroalkyl substituent on the quaternary nitrogen atom. Processes for the preparation of these salts and compositions containing them are described. These salts and their compositions are active antimicrobial agents.

Description

Unite States Patent Robertson [4 1 Aug. 1, 1972 [54] QUATERNARY FLUORINATED [56] References Cited AMMONIUM SALTS UNITED STATES PATENTS [72] Inventor: Jerry E. Robertson, North Oaks,

Minn. 2,581,336 1/1952 Hartmann et a] ..260/567.6 M

[73] Assignee: Minnesota Mining and Manufactur- Primary Examiner-Leon Zltver mg F samt Paul Assistant Examiner-Michael W. Glynn Flledi April 13, 1970 Att0rneyKinney, Alexander, Sell, Steldt & Delahunt [21] A l.No.: 27 976 pp 57 ABSTRACT [52] US. Cl....260/501.15, 260/567 6 M, 260/570,? The disclosed quaternary ammonium salts contain a 424/329 252 3 57 hydrofluoroalkyl substituent on the quaternary [51] Int. Cl ..C07c 87/30 n t g t m. r s s f th pr paration f these [58] Field of Search....260/567.6 M, 567.6 R, 501.15 salts and compositions containing them are described.

These salts and their compositions are active antimicrobial agents.

8 Claims, No Drawings QUATERNARY FLUORINATED AMMONIUM SALTS FIELD OF THE INVENTION pounds and compositions containing them are active antimicrobial agents.

DESCRIPTION OF THE PRIOR ART Many quaternary ammonium salts are known, and some are active antimicrobial compounds. An example of a known antimicrobial compound of this type is:

wherein X is halogen. See U. S. Pat. No. 2,581,336. When prior art quaternary ammonium salts of this type are dissolved in a suitable liquid carrier and used as disinfectants for bandages or instruments or used in similar in vitro applications, the antimicrobial solution does not penetrate well into crevices, holes, cracks and other tiny spaces in the bandage, surgical instrument, or other item to be disinfected. This poor physical penetration of the surface to be disinfected is apparently due to the surface tension of the carrier or solvent for the antimicrobial compound.

It is known that quaternary ammonium salts having a fluorocarbon tail-containing substituent on the quaternary nitrogen have utility as surface active agents, due to the hydrophobic and oleophobic properties of the tail. See, for example, U. S. Pat. No. 2,759,019, issued Aug. 14, 1956. So far as the applicant is aware, however, compounds similar to those of the US. Pat. No. 2,759,0l9, have notbeen tested for antimicrobial activity. More importantly, the fiuoroor perfluorododecyl analogues of the compounds disclosed in U. S. Pat. No. 2,581,336, are not known per se and, a fortiori, have not been tested for antimicrobial activity.

Accordingly, this invention contemplates providing chemical compounds which combine both surface tension lowering and antimicrobial properties.

SUMMARY OF THE INVENTION This invention relates to quaternary ammonium salts containing four aliphatic substituents bonded to the nitrogen atom, and their novel and useful properties as antimicrobial agents. These compounds have the formula Formula I wherein A is a pharmaceutically acceptable anion; Y is hydrogen, halogen or a trifluoromethyl radical which is substituted ortho, meta, or para to X, preferably ortho or para; X is a methylene, ethylene or oxyethylene radical; and R, is a straight or branched chain perfluoroalkyl radical of four to carbon atoms or an omegahydro-perfluoroalkyl radical of four to 10 carbon atoms.

It is a surprising feature of this invention that compounds within the preceding definition of Formula I have both surface tension lowering and antimicrobial activity, as will be described in detail subsequently. Closely analogous compounds, i.e. those wherein R, can have two or more hydrogen substituents, and/or wherein the R; carbon chain is shorter than four carbons, appear to be inactive when tested by the usual in vitro methods for an inhibitory effect on, for example, Bacillus subtilis, Staphylococcus aureus, Escherichia 0 coli, Streptoccocus sp. and Aspergillus niger.

However, the compounds of Formula I do possess antimicrobial activity, as is evidenced by in vitro tests for inhibitory effects on the growth of B. subtilus. It is difficult to account for the difference in behavior between these two closely related classes of compounds, i.e. the above-defined Formula I compounds and the shorter carbon chain and/or less fluorinated analogues. Apparently, when fluorocarbon chains are substituted on the nitrogen of a quaternary amine salt, the pattern of antimicrobial activity becomes unpredictable. It is a feature of this invention that a specific class of fluorocarbon-containing quaternary amines, i.e. that defined by Formula I, has been discovered which possesses the desired surface tension lowering activity and yet retains the antimicrobial activity sometimes attributed to quaternary amine salts.

The antimicrobial activity of the compounds of Formula I has been established by comparisons with standard antimicrobials such as chlorhexidine acetate and cetylpyridinium chloride. For example, when-R, is n- C F and Y is hydrogen, Formula I is active against Streptococcus sp. and S. aureus, as well as B. subtilis. When R, is C F Y is hydrogen; X is ethylene or oxyethylene; and A is trifluoromethanesulfonate or iodide; Formula I has a spectrum of activity including E. coli and A. niger, as well as the Bacillus, Streptococcus, and Staphylococcus organisms already mentioned. In addition, these compounds have excellent surface tension lowering properties, particularly when compared with known antimicrobial agents and even with known commercial surface tension lowering agents.

DETAILED DESCRIPTION OF THE INVENTION This invention relates to compounds of the formula:

' [YC H,XN(CH --CH R,]*A

Formula I wherein A is a pharmaceutically acceptable anion, e.g. halide, sulfate, trifluoromethanesulfonate, etc.; Y is hydrogen, halogen, or trifluoromethyl radical; X is a methylene, ethylene or oxyethylene radical and R, is a straight or branched chain perfluoroalkyl radical of four to 10 carbon atoms or an omegahydro perfluoroalkyl radical of four to ten carbon atoms. When Y is halogen or a trifluoromethyl radical, it is substituted ortho, meta, or para to X, preferably ortho or para.

Preferred compounds of Formula I are those wherein Y is hydrogen, X is ethylene or oxyethylene, and R, is perfluoroalkyl of six to nine carbon atoms.

The compounds of Formula I were tested for in vitro activities using, in essence, the method described by Vincent, J .G. and Vincent, Helen W., Proc. Soc. Exptl. Biol. Med, 55: 162-164(1953).

Vincent et al., op. cit., describe an agar-plate diffusion method employing culture media designed to meet the minimum essential requirements for the growth of the various test organisms. Suitable sugar-salts-agar media are described by Davis et al., op. cit., and are generally referred to as agar media. For example, an especially useful dextrose-salts agar medium contains: sodium and potassium bi-phosphate; magnesium, ammonium, and ferrous sulfate; calcium chloride; dextrose; ionagar; and distilled water. This medium is hereinafter referred to as the DG medium.

The compounds of the invention may be prepared by at least one of several synthetic routes. Synthesis 1) illustrates the reaction of a secondary amine containing one N-methyl substituent with a fluoroalkylating agent to form a tertiary amine. The tertiary amine may then be quaternized using a methylating agent known to the art such as methyl halides, methyl trifluoromethanesulfonate, dimethyl sulfate and the like.

Synthesis 1:

B is part of a suitable leaving group such as trifluoromethyl, p-tolyl, and the like, Z is a sub-class of A (as previously defined) which is a fragment of a known methylating agent such as bromine iodine, methyl sulfate, trifiuoromethanesulfonate and the like, and Y, X and R, are as defined previously.

Synthesis (2) illustrates a variation of Synthesis (1) wherein a tertiary dimethylamine derivative is treated with a fiuoroalkylating agent. The tertiary dimethylamine compounds are known, or may readily be prepared by methods known to those skilled in the art, such as alkylation of dimethylamine with an aralkyl halide in the presence of base.

Synthesis 2:

Y, X, and R, are as defined previously, and A, in this case, would ordinarily be B50 wherein B is as defined previously; i.e. Compound 111 would normally be Compound lIl.

Synthesis (3) illustrates another variation of Synthesis l wherein dimethylamine is reacted with a fluoroalkylating agent to form a tertiary amine. This tertiary amine is then quaternized by reaction with an aralkyl halide.

Synthesis 3:

(CH )|NH BSOaCHgR; (CH:)1NCH:R; HB

III VIII IX Y, X, R, and B are as defined previously, and Z, in this case, is a halogen of atomic number 17, 35 or 53.

In order to obtain compounds of the present invention where A is a specific pharmaceutically acceptable anion, the salts of this invention may be obtained directly, by anion interchange using methods well known to the art such as anionic exchange column chromatography, selective precipitation in appropriate solvents or neutralization followed by reprecipitation using a selected anion.

As antimicrobial agents, the compounds of this invention may be applied directly to the microbes or conventional carriers and diluents may be incorporated with them before application. The choice of carrier or diluent and the concentration of the active ingredient are determined by the use of the composition.

Suitable carriers and diluents include ointments, organic solvents (for example ethanol), water, solid inert materials such as talc, bentonite, kieselguhr, diatomaceous earth and the like. Emulsifying agents may be used with the compounds of this invention. The compounds may also be contained in surgical drapes and the like.

The following examples illustrate the invention, but are not to be regarded as limiting it in any way.

EXAMPLE 1 N-( 1 l -Dihydroperfluoro-n-octyl)-Nmethyl-N( 2- phenoxyethyl )amine (Compound IVa) Equimolar amounts N-methyl-N-(2-phenoxyethy1) amine, a secondary amine of Formula II of Synthesis (1), supra, and l,l-dihydroperfluoro-n-octyltrifluoromethanesulfonate, (see U. S. Pat. No. 3,419,595 to Robert L. Hansen, issued Dec. 31, 1968) a pertluoroalkyl sulfonate of Formula 111 of Synthesis (1), supra, were combined as follows: 22.24 g. (0.147 mole) of the aforementioned Formula 11 amine, and 78.2 g. (0.147 mole) of the aforementioned Formula 111 sulfonate were added to a mixture of 250 ml. of dry methyl ethyl ketone over 20 g. (0.145 mole) of finely powdered anhydrous potassium carbonate. The mixture was stirred at room temperature for one hour and then gradually heated up to reflux temperature over a period of an hour. The mixture was then stirred at this temperature for sixteen hours. The solid was then filtered from the mixture and discarded. The filtrate was evaporated in vacuo to yield a high boiling residue which was vacuum distilled.

Analytically pure N-( l ,1-dihydroperfluoro-n-octyl)- N-methyl-N-(2-phenoxyethy1) amine, a compound of Formula 1V (Synthesis (1)) hereinafter called Compound lV-a, was obtained. The boiling point of Compound lV-a at 0.18 mm. was found to be C. The elemental analysis was as follows:

Calculated for C -,H, F NO:C, 38.3; H, 2.6; N, 2.6

Found: C, 38.5; H, 2.6; N, 2.6

EXAMPLE 2 Using the general procedure of Example 1, secondary amines of Formula ll (hereinafter Compound ll-b, etc.) were combined with dior tri-hydroperfluoro compounds of Formula lII (hereinafter Compound III-b, etc.) as follows:

Formula Ill Fonnula ll Dior tri-hydroperfluoro- Secondary Amine alkyl Sulfonate No. Compound Name No. Compound Name II-b Nmethyl-N-( 4- lll-b l, l -dihydroperchlorobenzyl)amine fluoro-n-pentyltrifluoromethanesulfonate ll-c N-methyl-N-[2-(4- triiluoromethyl Ill-c l, l -dihydroperphenoxy)ethyl]amine fluoro-n-decyltrifluoromethanesulfonate ll-d N-methyl-N-( 2- lll-d l, l ,9-trihydroperfluorobenzyl)amine fluoron-nonyltrifluoromethanesulfonate ll-e N-methyl-N-( Z-phenlll-e l,l-dihydroperethyl amine fluoro-n-octyltrifluoromethanesulfonate llf N-methyl-N-benzylill-f l,l-dihydroperamine fluoro-n-heptyltrifluoromethanesulfonate The resulting Formula IV tertiary amines (Compound lV-b, etc.) were as follows:

No. Name lV-b N-(l l -dihydroperfluoro-n-pentyl)-N-methyl- N-(4-chlorobenzyl)amine lV-c N-(l l -dihydroperfluoro-n-decyD-N-methyl- N-[Z-(4-trifluoromethylphenoxy)ethyl] amine IV-e N-(l ,l -dihydroperfluoro-n-octyl)-N-methyl- N-(2-phenethyl)amine lV-f N-(l l -dihydroperfluoro-n-heptyD-N-methyl- N-benzylamine EXAMPLE 3 N-( l ,l-Dihydroperfluoro-n-octyl)-N,N-dimethyl-N-(2- phenoxyethyl)-ammonium iodide (Compoundl-a,

iodide) 20 grams (0.14 mole) of methyl iodide, grams (0.019 mole) of Compound IVa (see Example 1), and 250 ml. of ethanol were heated at reflux temperature for 23 hours. The ethanol was evaporated to give an oil which was poured into diethyl ether. The precipitate which formed was recrystallized from methanol/diethyl ether to yield colorless crystals of Compound l-a (iodide), m.p. l45-l47 C.

Analysis:

Calculated for C H F, lNO: C, 32.0; H, 2.5; N, 2.] Found C, 32.1; H, 2.6; N, 2.0

EXAMPLE 4 Using the general procedure of Example 3, the tertiary amines made according to Example 2 (Compound IV-b, etc.) were reacted with methylating agents (methyl halides), as follows:

The resulting quarternary amines of this invention (Compound I-b, etc.) were as follows:

Name

N-( l ,I -dihydroperfluoro-n-pentyl)-N,N-

dimethyl-N-(4-chlorobenzyl)am monium iodide N-(l l -dihydroperfluoro-noctyl)-N ,N-

dimethyl-N {Z-phenethyhammonium iodide N -(l -dihydroperfluoro-n-he ptyl)-N .N

dimethyI-N-benzylammonium bromide EXAMPLE 5 N-( l l -Dihydroperfluoro-n-octyl )-N,N-dimethyl-N-( 2- phenoxyethyl) ammonium trifluoromethane sulfonate (Compound l-a, trifluoromethane sulfonate) Compound lV-a (see Example 1) was converted to a quaternary amine salt in a manner analogous to the procedure of Example 3, except that the methylating agent was methyl trifluoromethanesulfonate instead of a methyl halide. Compound lV-a (15.0 g.; 0.028 mole) was dissolved in 50 ml. of absolute diethyl ether and methyl trifluoromethanesulfonate (14.8 g.; 0.09 mole) was added to the solution. A slight heat of reaction was observed and within two minutes the colorless solid product crystallized from solution. This product was filtered from the mixture, washed with ether and dried. The trifluoromethanesulfonate form of compound l-a, m.p. l03-l08 C., was obtained analytically pure by recrystallizing the product from methanol-diethyl ether.

EXAMPLE 6 N-( l l -Dihydroperfluoro-n-octyl)-N,N-dimethyl-N-( 2- phenethyl)- ammonium trifluoromethanesulfonate (Compound I-e, trifluoro-methanesulfonate) Dimethyl phenethylamine (3.0 g., 0.02 mole) was dissolved in 25 ml. of methyl ethyl ketone and added dropwise at 50-60 to a solution of 21.38 g. of 1,1- dihydroperfluoro-n-octyl trifluoromethanesulfonate (Compound llI-e) in ml. methyl ethyl ketone. Heating (5060) and stirring was continued for two hours. All operations were carried out in a nitrogen atmosphere. The reaction mixture was evaporated to one-half of its original volume and 240 ml. diethyl ether was added. The precipitate was filtered and dissolved in hot ethanol. The pure trifluoromethanesulfonate form of Compound l-e, m.p. l53l55 C. precipitated on addition of diethyl ether.

Analysis.

Calculated for c,,H.,F,,.No s; C, 33.5; H, 2.5 Found C, 33.8; H, 2.5

EXAMPLE 7 In Vitro Assay of Representative Compounds of Formula I The in vitro inhibitory effect of Compounds l-a (iodide) and l-e trifluoromethanesulfonate upon B. subtilis was tested substantially according to the method of Vincent et al., op. cit., and Davis et al., op. cit. The DG culture medium used for growth of B. subtilis was as follows:

Potassium hydrogen phosphate Sodium hydrogen phosphate-dihydrate m sulfate-hepta hydrate Ammonium sulfate Calcium chloridedihydrate Ferrous sulfate-heptahydrate This DG medium was supplemented with amino acids by melting the medium in a steam bath, adding the amino acid supplement, and cooling the supplemented medium to 42 C. in a water bath. The amino acid supplement was as follows: 600 mg/liter glutamic acid, 200 mg/liter cystine, 800 m.g.lliter asparagine, and 20 m.g./liter disodium salt of ethylenediaminetetracetic acid. Between 10 and 10 cells of B. subtilis were added per ml. of the DG-amino acid medium, and the resulting medium was dispensed, at 10 ml. per dish, into two 9 cm. circular plastic petri dishes. After cooling, a 6.5 mm disc of Whatman No. 2 filter paper was dipped into a 1 percent (by weight) acetone solution of Compound I-a (iodide), allowed to air dry, and laid on the surface of an innoculated plate. A second 6.5 mm. disc was likewise treated with a 1 percent acetone solution of Compound l-e (trifluoromethane sulfonate) and laid on an innoculated plate after an identical drying step. Tests show that the dipping step will cause three to five microliters of solution (containing 30-50 micrograms of compound) to impregnate each disc. The plates were incubated at 30 C. for 24 hours, and the diameters of the zones of inhibition were measured, the magnitude of the diameter being an indication of the effectiveness of the inhibition. The diameter of the zone of inhibition for Compound l-a (iodide) was 30 mm.; that of Compound l-e (trifluoromethanesulfonate) was 33 mm.

Compounds I-a (iodide) and I-e (trifluoromethanesulfonate) were also tested in an analogous manner, using appropriate culture media and incubation periods, for inhibition of the growth of S. aureus, Streptococcus sp., E. coli, and A. niger. Inhibitory zones ranging from 10-23 mm., depending on the organism and the test compound, were observed.

In overall evaluations of spectrum and effectiveness of in vitro inhibitory activity the compounds of Formula 1 were comparable to cetyl pyridinium chloride and chlorhexidine acetate, two standard antimicrobial compounds known to inhibit the growth of at least one of the aforementioned microorganisms.

When the following compound:

was tested and compared with standards in exactly the same manner as Compounds I-a and le, no inhibitory effect whatever was observed on any of the organisms mentioned in this Example. The difference in activity could not be explained, but was attributed to the ethoxy component and/or the shorter carbon chain of the fluorocarbon-containing substituent.

EXAMPLE 8 The outstanding surface tension lowering properties of compounds of the present invention are exemplified by the following tabulation, which compares a compound of the invention with cetyl pyridinium chloride, a well known commercial antimicrobial agent, and Alevaire a brand of tyloxapol, a commercial surface tension lowering agent.

Comparison of Surface Tension Lowering Surface Tension Concen- (in dynes Compound tration m. Temperature Compound la 50 mg. 22 F. (35C.)

/50 ml. (iodide) 28 72F. (22.2C.) Cetyl pyridinium 25 mg. 42 73F. (22.8C.)

/50 ml. chloride 50 mg. 45.5"

I50 ml. Alevaire commercial 40.7 7lF. (2|.7C.) (tyloxapol sample (av. of composition) 3 trials) A standard antimicrobial compound; see Example 7.

"Literature value at 25 C. (77F), 50 mg./ml is 43 dynes/cm. [Merck Index, 7th Edition, p. 227 I960), Merck Co., Inc.. Rahway. New Jersey.]

The measurements were taken using standard methods with an lnstron Universal Testing Machine and a DuNuoy ring at a rate of l cm./min.

What is claimed is:

1. A compound of the formula wherein:

A is a pharmaceutically acceptable anion;

Y is selected from the group consisting of hydrogen,

halogen and trifluoromethyl;

X is selected from the group consisting of methylene,

ethylene and oxyethylene; and

R, is selected from the group consisting of perfluoroalkyl radicals of four to 10 carbon atoms and omega-hydro-perfluoroalkyl radicals of four to 10 carbon atoms.

2. A compound according to claim 1 wherein Y is hydrogen.

3. A compound according to claim 1 wherein R, is a straight chain perfluoroalkyl radical of four to 10 carbon atoms.

4. A compound according to claim 2 wherein X is selected from ethylene or oxyethylene and R, is a perfluoroalkyl radical of six to nine carbon atoms.

5. A compound according to claim 1 wherein said compound is an N-( l l -dihydroperfluoro-n-octyl)-N,N-dimethyl-N- (2-phenoxyethyl )ammonium salt, the anion of said salt being said pharmaceutically acceptable anion.

6. A compound according to claim 5 wherein said anion is iodide.

7. A compound according to claim 1 wherein said compound is an N-( l l -dihydroperfluoro-n-octyl)-N,N-dimethyl-N- (2-phenethyl )ammonium salt, the anion of said salt being said pharmaceutically acceptable anion.

8. A compound according to claim 7 wherein said 5 anion is trifluoromethanesulfonate.

STA PATENT @FMQE QE'HFMA'EE n Patent No. 3, Dated g st 1, 1972 Inventor(s) rry E. Robertson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Ihe Title should read, as follows: FLUORINATED QUATERNARY AMMONIUM SALTS Column 1, line 17, delete the "c", so that the first portion of the formula reads, as follows:

Column 2, lines 37- 42, correct type style (remove italics).

The only italicized words in these lines are E coli and A niger 5 line 65, change "(1953)" to (19 4 4) and at the end of the line change the period to a comma and insert: and Davis and Mingioli, Jour. Bact. 66: 29-136 (1953) o Column 5, line 21, after "ethyl" and before "amine" insert a parenthesis and move these words to the right to line up with the column headed "Compound Name".

Column 7, line &8, insert C before "F" at the end of the line, line &9, insert B after the so the formula will read:

[C H CH CH N(CH -CH CH OCH CF CF H] Bl" line 5 1, delete the hyphen at the end of the line and insert y to complete ethoxy line 55, delete "y" at the beginning of the line.

Signed and sealed this 13th day of March 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents ORM O-I050 (10-69) UNITED STATES PATENT GFFICE CERTIFICATE 0F Patent No. 3, Dated August 1, 1972 Inventor(s) Jerry E. Robertson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The Title should read, as follows: FLUORINA'I'ED QUATERNARY AMMONIUM SALTS Column 1, line 17, delete the "0'', so that the first portion of the formula reads as follows:

Column 2, lines 37- 42, correct type style (remove italics).

The only italicized words in these lines are E coli and A niger line 65, change "(1953)" to (19 M) and at the end of the line change the period to a comma and insert: and Davis and Mingioli, Jour. Bact. 66: 129-136 (1953) a Column 5, line 21, after "ethyl" and before "amine" insert a parenthesis and move these words to the right to line up with the column he aded Compo und Name".

Column 7, line 48, insert C before "F" at the end of the line, line 49, insert B after the so the formula will read:

[C H CH CH N(CH -CH CH OCH CF CF H] BI line 5 delete the hyphen at the end of the line and insert y to complete ethoxy line 55, delete "y" at the beginning of the line.

Signed and sealed this 13th day of March 1973.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents RM PO-IOSO (IO-69) USCOMM-DC 60376-P69 Us GOVERNMENT PRINTING OFFICE: I989 0-386-334

Claims (7)

1. 2. A compound according to claim 1 wherein Y is hydrogen.
2. 3. A compound according to claim 1 wherein Rf is a straight chain perfluoroalkyl radical of four to 10 carbon atoms.
3. 4. A compound according to claim 2 wherein X is selected from ethylene or oxyethylene and Rf is a perfluoroalkyl radical of six to nine carbon atoms.
4. 5. A compound according to claim 1 wherein said compound is an N-(1,1-dihydroperfluoro-n-octyl)-N,N-dimethyl-N-(2-phenoxyethyl)ammonium salt, the anion of said salt being said pharmaceutically acceptable anion.
5. 6. A compound according to claim 5 wherein said anion is iodide.
6. 7. A compound according to claim 1 wherein said compound is an N-(1,1-dihydroperfluoro-n-octyl)-N,N-dimethyl-N-(2-phenethyl)ammonium salt, the anion of said salt being said pharmaceutically acceptable anion.
7. 8. A compound according to claim 7 wherein said anion is trifluoromethanesulfonate.