IL44079A - Antimicrobial compositions comprising 5-bromo-5-nitro-2-alkylsubstituted-1,3-dioxanes - Google Patents

Description

44079/2 ANTIMICROBIAL COMPOSITIONS COMPRISING 5-.BROMO-5- NITRO-2-ALKYLSUBSTITUTED-l,3-DIOXANES -inna-5 o'ilCbpiN' s. i D'7'ann D'in'n -TAJ π»νκοη antimicrobial compositions comprising as active ingredient The present invention relates to/5-bromo-5-nitro-2-alkylsubstituted-1 , 3-dioxanes , such as 5-bromo-2-methyl-5- which are nitro-1, 3-dioxane, novel antimicrobials with activity against both bacteria and fungi.

A wide variety of antimicrobials are known. A large number of antibiotics and synthetic organic chemicals are useful as bacteriostats , bacteriocides , fungistats, fungicides, et seq. Many of these effective antimicrobials have an important role in controlling the microorganisms that infect man. Some have a broad scope of activity while others, find a place in a narrow range of applications. A few are even limited to a single utility.

Antimicrobial preservatives are recognized as important ingredients in cosmetic creams used as bases for facial make-up. These creams are generally comprised of an oil in water emulsion. The ingredients furnish a fertile substrate for microorganisms such as bacteria and fungi. Moreover, as both oil and water are present, the choice of an appropriate preservative requires attention to the need for antimicrobial activity in both systems.

Inasmuch as it is likely that an effective antimicrobial works best when it is soluble in the substrate to be protected, it is important than a preservative for such a cosmetic cream should have an effective solubility in both oil and water.

A preservative which has been employed in cosmetic creams with some degree of success is 2-bromo-2-nitropropane- 44079/2 which are the active ingredient of the conpbsitiohs , he useful compounds pf the instant invention, can be prepared !utilizing 2-bromo-2-nitropropane-i,'3-diol as the starting material . The compound, 2-bromo-2-nitropropane 1,3-diol is commercially available under the trademark. .

Bronopol, and' can be prepared in several different ways.

One efficient process involves using nitromethane as a reactant and combining it with formaldehyde to form 2-nitrop oj3ane-l, 3-diol, converting the latter to the sodium salt and brominating such salt to get 2-bromo-2-nitropropane-1 , 3-diol. Preparation 1 exemplifies the preparation of , 2-bromo-2-nitrbpropane-l, 3-diol from nitromethane.1 Preparation 1 Twenty grams (0.5 mole) of sodium hydroxide were dissolved in 400 ml. of water and the solution was cooled to 10eC. To 74 ml. of 35% formaldehyde (1.0 mole) were added 76 ml. of the previously prepared sodium hydroxide solution. Then to the combined formaldehyde-sodium hydroxide solution were added dropwise 27 ml. (0.5 mole) of nitromethane, all the while holding the reaction temperature between 25-30°C. by immersing the reaction vessel in an ice-water bath. The reaction of the nitromethane and formaldehyde was catalyzed by the sodium hydroxide and 2-nitropropane-l , 3-diol was formed, but not isolated.

The diol was then converted to the sodium salt by adding the remainder of the previously prepared sodium hydroxide solution to the reaction vessel at 20 °C. and the reaction mixture was stirred at room temperature and atmospheric pressure for 1/2 hour.

Three-hundred milliliters of ethyl acetate were cooled to -5°C. utilizing an ice-acetone bath. To the cooled ethyl acetate were added 25.5 ml. (0.5 mole) of bromine in a slow steady stream holding the temperature at 5°C. or below. Then the previously prepared sodium 2-nitropropane-l , 3-diol reaction mixture was slowly added to the ethyl acetate-bromine mixture holding the temperature in the 5-10°C. range. The reaction mixture was stirred for 5 minutes at room temperature and atmospheric pressure, after which the pH was adjusted to 2.0 with 6N HC1. Two-hundred grams of sodium chloride were added to the reaction mixture driving the .2-bromo-2-nitro-propane-1 , 3-diol into the ethyl acetate layer.

The ethyl acetate fraction was separated from the water fraction and dried over magnesium sulfate, and filtered. The ethyl acetate was removed from the filtrate under vacuum and the resulting dry solids were washed with methylcyclo-hexane and again reduced to dryness. Eighty-three and one-tenth gram (83.1% yield) of 2-bromo-2-nitropropaner-l , 3-diol were recovered which had a melting point of 108-114 °C.

The novel compounds of this embodiment of the present invention can be prepared by reacting an appropriate aldehyde with the 2-bromo-2-nitropropane-l , 3-diol , from Preparation I, in an acidic environment. The preparation of 5-brpmo-2-methyl-5-nitro-l , 3-dioxane is exemplified in Example 1.

Example 1 Forty grams (0.2 mole) of 2-bromo-2-nitropropane- 1,3-diol were suspended in 200 ml^ of benzene and about 0.3 g of p-toluene sulfonic acid was added. The mixture was cooled in an ice-water bath and a condenser attached to the reaction vessel. About 13.5 g. (0.3 mole) of acetaldehyde were slowly added through the condenser and the reaction mixture was stirred for 30 minutes. A Dean-Stark trap was connected and the mixture warmed slowly, then heated to reflux until' water no longer was evolved. (About 4 ml . of water was evolved in 1.5 hours). The solution was filtered and evaporated on a rotating evaporator at about 45 °C. A dark oil residue was obtained, which was vacuum distilled at 0.25 mm. Thirty-six and one-half grams (85% yield) of 5-bromo-2-methyl-5-nitro-l,3-diox*ne were obtained havinq a boiling range at 0.25 mm. of from 72-74 °C. The N R and IP. were consistent with the structure, and an elemental analysis disclosed the followina percentage composition: C: calc. 26.57, found 26.85; H: calc. 3.57, found 3.85; N: calc. 6.20, found 6.04; Br: calc. 35.35, found 35.21.

The compound, 5-bromo-2-methyl-5-nitro-l , 3-dioxane is a water clear, colorless liquid at room temperature, and does not solidify at -10°C. It is chemically stable at pH's from 5.0 to 9.0 and has an acrid pungent odor faintly resembling bromine.

Example 2 The compound 5-bromo-2-ethyl-5-nitro-l , 3-dioxane was prepared following the procedure outlined in Example 1 by substituting propionaldehyde for the acetaldehyde. The NMR was consistent with the structure, and an elemental analysis disclosed the following percentage composition: C: calc, 30.02; found 30.24 H: calc, 4.20; found 4.24 N: calc.,- 5.83; found 5.92 Br: calc, 33.29; found 32.99 The white crystalline material had a melting point of 58-59 The compound is chemically stable at pH ' s from 5-9 and has the same acrid pungent odor faintly resembling bromine that is exhibited by the methyl derivative.

Example 3 The compound 5-bromo-5-nitro-2-n-propyl-l , 3-dioxane was prepared following the procedure outlined in Example 1 by substituting n-butyraldehyde for the acetaldehyde. The NMR and IR were consistent with the structure, and an elemental analysis disclosed the following percentage composition: C: calc, 33.09; found 33.32; H: calc, 4.76; found 4.63; N: calc. , 5.51, found 5.66; Br: calc, 31.45; found 31.64; The compound obtained was a colorless oil which, when distilled at 0.005 mm Hg, had a boiling point of 73-75° C. The oil solidified to a waxy solid on standing at room temperature. The acrid pungent odor of bromine was present.

Example 4 'The compound 5-bromo-2-isopropyl-5-nitro-l , 3- dioxane was prepared following the procedure outlined in Example 1 by substituting isobutyraldehyde for the acetalde- hyde. The NMR and I were consistent with the structure, and an elemental analysis disclosed the following percentage composition: C: calc. , 33. 09; found 33. 33 H: calc . , 4. 76; found 4. 83 N: calc . , 5. 51; found 5. 33 Br: calc . , 31. 45; found 31. 24 The compound obtained was a colorless crystalline material which, after recrystallization from a 1:1 isopropanol water solvent had a melting point of 42-44 °C. The acrid, pungent odor of bromine was present.

The novel compounds of this embodiment of the present invention, exemplified in Examples 1, 2, 3, and 4 can exist as cis- and trans-isomers . The procedure outlined in Example 1 produces a ratio of isomers of about 9:1. It is the intent of this invention to include both geometric isomers as chemical entities as well as the isomeric mixture. Antimicrobial tests on isomeric mixtures of 5-bromo-2-methyl-5-nitro-l , 3-dioxane , one high in the cis- form and the other high in the trans- form, showed equal activity, indicating no significant difference in the usefulness of the two geometric isomers. Consequently, the utility tests described hereinafter were conducted employing the isomeric mixture (about 9:1) prepared as detailed in Example 1.

One of the useful compounds, 5-bromo-2-methyl-5- nitro-1 , 3-dioxane is outstandingly effective in vitro against a wide spectrum of microbial organisms, both bacteria and fungi. Moreover, the antimicrobial activity of this useful compound is up to 20 times that of the prior art compound, 5-bromo-5-nitro-l , 3-dioxane . For example, this active compound of the present invention has a minimum inhibitory concentration (MIC) of 5 meg. /ml. against each of Corynebacterium acnes and Staphylococcus aureus compared with an MIC of 100 meg. /ml. for 5-bromo-5-nitro-l , 3-dioxane against each of C^ acnes and S_^_ aureus in the conventional tube dilution test. In this test, the concentration of 4 the inoculated broth was 10 organisms/ml.

The in vitro activities of the active compounds, 5-bromo-2-methyl-5-nitro-l , 3-dioxane (Compound A), 5-bromo-5-nitro-l , 3-dioxane , (Compound B) , and 2-bromo-2-nitro-propane-1 , 3-diol (Compound C) were determined by streaking six organisms on agar plates containing the active antimicrobials A, B, and C. The MICs for Compound A were from one-fifth to one-thirty-third of the MICs observed for Compound B, and from one-twentieth to one-sixty-seventh of MICs recorded for Compound C. The tests were run concurrently and the microorganism count was 10 ^ organisms/ml. The microorganisms employed in the test and the test results are shown in Table I.

TABLE I In Vitro Antimicrobial Activity Minimum Inhibitory Concentration, meg. /ml. when Pseudomonas Streptococcus Staphylococcus Escher aeruginosa faecalis aureus col Compound A 1.0 1.0 2.5 2.

Compound B 25.0 10.0 15.0 10.

Compound C 20.0 20.0 . 50.0 20.

The antimicrobial activities of 5-bromo-2-methyl-5-nitro-l , 3-dioxane (Compound A) , 5-bromo-5-nitro-l , 3-dioxane (Compound B) , and 5-bromo-2-ethyl-5-nitro-l , 3-dioxane (Compound D) were determined concurrently against Pseudomonas aeruginosa , Staphylococcus aureus , and Escherichia coli in a conventional tube dilution test, and against Aspergillus lavus , Aspergillus niger , and Candida albicans utilizing agar plates. The concentrations of the organisms in the 4 tube dilution tests were 10 organisms per mil., an the concentrations streaked on the agar plates were 10 ^ organisms per ml. of agar. The figures shown in Table II are the lowest concentration in meg. /ml. of active compound in the broth or agar where no growth occurred. This was interpreted as the mimimum inhibitory concentration (MIC) for the active compound against each test organism.

TABLE II In Vitro Antimicrobial Activity Minimum Inhibitory Concentration, meg. /ml. when Pseudomonas Escherichia S Sttaapphhyyllooccooccccuuss Cand aeruginosa coli aureus albi Compound A 6.25 12.5 12.5 25 Compound B 12.5 25 12.5 50 Compound D 12.5 12.5 25 12 In another test the antimicrobial activities of 5-bromo-2-methyl-5-nitro-l , 3-dioxane (Compound A) , 5-bromo- 5-nitro-l , 3-dioxane (Compound B) , and 5-bromo-5-nitro-2-n-propyl-1 , 3-dioxane (Compound E) were determined concurrently against the same six organisms shown in Table I. Compound A was clearly superior to Compound B against four of the six organisms, and Compound E showed effectiveness as an antimicrobial. The tests were in vitro determinations utilizing agar plates containing the active compounds at 10, 25 and 50. meg. per ml. of agar. The organisms, at 6 concentrations of 10 organisms per milliliter, were streaked on the solidified agar. The plates were incubated for 24 hours and the presence or absence of growth noted. The minimum inhibitory concentration (MIC) was determined as the lowest active compound concentration in the agar where no growth occurred. Table III shows the results of this test.

TABLE III In Vitro Antimicrobial Activity Minimum Inhibitory Concentration, meg./ml. when Pseudomonas Streptococcus Staphylococcus Escher aeruginosa faecalis aureus col Compound A <10 <10 <10 <10 Compound B 25 <10 25 <10 Compound E >50 >50 25 25 In still another test the antimicrobial activities of 5-bromo-2-isopropyl-5-nitro-l , 3-dioxane (Compound F) were determined against the same six organisms shown in Table 1 plus Aspergillus flavus . MICs were determined by streaking the seven organisms on agar plates containing Compound F at various concentrations. The lowest concentration of the compound at which no growth was evident on the agar after incubation was recorded as the MIC. The microorganisms employed in the test and the test results are shown in Table IV.

TABLE IV In Vitro Antimicrobial Activity Minimum Inhibitory Concentration, meg. /ml. when test Pseudomonas Streptococcus Staphylococcus Escherichi aeruginosa faecalis aureus coli Compound F 50 25 25 50 The novel compounds of this invention also exhibit exceptionally good antifungal activity. This activity was determined against 16 common fungi, and against 14 of the 16 organisms, 5-bromo-2-methyl-5-nitro-l , 3-dioxarie had a lower MIC than that observed for 5-bromo-5-nitro-l , 3-dioxane in concurrently run tests. The tests were run by adding the test compound to melted agar in concentrations of 200, 100, 50, 25, and 10 meg. /ml., solidifying the agar and streaking the organisms thereon. The results of the test shown in Table V.

TABLE V In Vitro Antifungal Activity Minimum Inhibitory Con meg. ml. of 5-bromo-2-methyl- 5-nitro-l , 3-dioxane in agar Aspergillus fumigatus 25- 50 Aspergillis terreus 50-100 Penicillium notatum >100 Microsporum gypseum 50-100 Saccharomyces cerevisiae 50-100 Fusarium bulbigenum 10- 25 Fusarium oxysporum cubense 10- 25 Fusarium oxysporum lycopersici 10- 25 Colletotrichum phomoides 25- 50 Chaetomium globosum 10- 25 Pullularia pullulans 50-100 Xanthomonas malvaciurum 10- 25 Rhodotorula glutinis >100 Trichophyton interdigitale 10 Trichophyton mentagrophytes >100 Pityrsporum ovale 50-100 The antifungal activities of Compounds A and B (5-bromo-2-methyl-5-nitro-l , 3-dioxane and 5-bromo-5-nitro-1, 3-dioxane, respectively) were determined for seven fungi and one yeast in still another test. Aqueous concentrations of 0.1, 0.05, and 0.025 percent by weight of each of Compounds A and B were inoculated to contain approximately 10^ organisms per ml. Viable organism counts were made initially and at 24 hours, as shown in Table VI. Compound A was observed to be significantly more effective than Compound B against the yeast, Saccharamyces pastorianus at a concentration of 0.025 percent. Additionally, Compound A had an increased activity over Compound B against Trichophyton mentagrophytes .

TABLE VI In Vitro Antifungal Kill Effectiveness Viable Organism Count after Incu Organism Count per Percent Concentration ml . when of 5-Bromo-2-Methyl- Antimicro 5-Nitro-l , 3-Dioxane bial Compound is Organism Added 0.1 0.05 0.025 Aspergillus fumigatus 4 X 106 <100 <100 <100 Penicillium notatum 3 X 106 <100 <100 <100 Microsporum gypseum 8 X 108 <100 200 <100 Saccharomyces pastorianus 2 X 107 <100 <100 In the instant invention, the 2-methyl derivative of 5-bromo-5-nitro-l , 3-dioxane is an especially preferred species .

An evaluation was made of skin irritating and skin sensitizing properties of the prior art compound 5-bromo-5- nitro-1 , 3-dioxane and the especially preferred compound of this invention, 5-bromo-2-methyl-5-nitro-l , 3-dioxane . The following protocol was followed in testing each compound.

Two hundred subjects were employed in each investigation. The repeated insult technique was used in the patch test. A different group of subjects were utilized for each evaluation.

The technique used for the patch test called for a series of 9 induction patches of each test material to be placed on each of the subjects. The series was followed two weeks later by a single "challenge" patch of each test material to detect skin sensitization.

The series of nine induction patches was applied on Monday, Wednesday and Thursday and allowed to contact the skin for 24 hours, after which time they were removed and the skin sites graded for irritation. Thursday's patches were placed immediately after removal and grading of Wednesday's applications. After the ninth induction patches had been placed, a non-patching period of 2 weeks elapsed before the challenge patches were applied to detect sensitization reactions. For this 24-hour patch, a new skin site was used. This site was invariably chosen adjacent to an induction site? i.e., one where repeated applications had been made during the series of nine induction patches. The challenge applications were graded at 24 and 72 hours after application.

The skin applications for each material were made using oval-shaped adhesive patches (1" x 1 1/4") with circular gauze centers. The gauze centers were coated with approximately 0.03 ml. of the respective test material just prior to application.

The scoring criteria used for skin irritation reactions and in evaluating the sensitization evidenced on the challenge application follows: TABLE VII Human Repeated Insult Patch Test Scoring Criteria for Skin Reactions Erythema and Eschar Formation No reaction 0 Very slight erythema (barely perceptible) 1 Mild, well-defined erythema 2 Moderate to severe erythema 3 Severe erythema (beet redness) to slight eschar formation (injuries in depth) 4 Total Possible Erythema Score 4 Edema Formation No reaction 0 Very slight edema (barely perceptible 1 Slight edema (edge of area well- defined by definite raising) 2 Moderate edema (area raised approximately 1 mm) 3 Severe edema (area raised more than 1 mm and extending beyond area of exposure) 4 Total Possible Edema Score 4 Total Possible Primary Irritation Score 8 Four separate formulations of each compound were tested along with .two formulations of parabens. These formulations were all cosmetic creams at different concentra- . tions of the active compounds as shown in Table VIII.

TABLE VIII Test Concentration Type Material Active Compound Percent of Cream A 5-bromo-5-nitro- 0.05 Nonionic B 1 , 3-dioxane 0.1 Nonionic C 0.05 Anionic D 0.1 Anionic E 5-bromo-2-methyl-5- 0.01 Nonionic F nitro-1 , 3-dioxane 0.1 Nonionic G 0.01 Anionic H 0.1 Anionic K Parabens 0.6 Nonionic L 0.6 Anionic Table IX below shows a summary of the scores all the tests.

TABLE IX Comparison of the Irritation and Sensitization of 5-bromo-5-nitro-l , 3-dioxane and 5-bromo-2- methyl-1 , 3-dioxane in a Human Repeated Insult Patch Test. 5-BROMO-5-NITRO-1 , 3-DIOXANE Induction Series of Applications Total Number of Reactions Test Number of with Scores of: Material Reactors 0 1 2 3 4 5 6 7 8 A 25 1766 18 3 3 1 1 1 0 0 B 41 1735 29 12 9 3 3 0 0 2 C 21 1768 18 6 1 0 1 1 0 0 D 56 1693 59 23 6 6 2 4 0 0 K 19 1771 21 5 0 0 0 0 0 0 L 20 1767 21 5 2 1 1 0 0 0 Challenge Application Total Number of Reactions Test Number of with Scores of: Material Reactors 0 1 2 3 4 5 6 7 8 A 3 197 0 0 1 1 0 1* 0 0 R 11 189 2 2 2 1 1* 2* 0 1* C 2 198 0 0 1 0 0 1* 0 0 D 20 18 1 5 2 5 1* 3* 1* 2* 2 198 1 1 0 0 0 0 0 0 L 1 199 0 0 0 1 0 0 0 0 *Indicative of skin sensitization 5 -BPOMO-2-METHYL-5-NITRO-1 , 3-DIOXANE Induction Series of Applications Total Number of Reactions Test Number of with Scores of: Material Reactors 0 1 2 3 4 5 6 7 8 E 13 1787 13 0 0 0 0 0 0 0 F 26 1774 23 2 1 0 0 0 0 0 G 25 1775 22 1 2 0 0 0 0 0 H 25 1775 21 2 2 0 0 0 0 0 K 20 1777 19 4 0 0 0 0 0 0 L 24 1776 22 2 0 0 0 0 0 0 TABLE IX (Cont. ) Challenge Application Total Number of Reactions Test Number of with Scores of: Material Reactors 0 1 2 3 4 5 6 7 8 E 0 200 0 0 0 0 0 0 0 0 F 0 200 0 0 0 0 0 0 0 0 G 0 200 0 0 0 0 0 0 0 0 H 2 198 2 0 0 0 0 0 0 0 K 1 199 1 0 0 0 0 0 0 0 L 2 198 2 0 0 0 0 0 0 0 From the data in Table IX it is clear that 5-bromo- 5-nitro-l , -dioxane showed a marked sensitizing effect wherein 11 of the 200 subjects were evaluated as being sensitive to a 0.1 percent concentration of the compound on the challenge test, while none of the 200 subjects challenged with a 0.1 percent concentration of 5-bromo-2-methyl-5-nitro-l , 3-dioxane were considered to be sensitive to the latter compound. A reading of 5 or more on the 8-point scale was deemed to be indicative of the development of skin sensitization to the test compound. Moreover, the irritation readings associated with the prior art compound were more severe than those recorded for the 2-methyl derivative thereof.

The novel compounds of this invention have the important property of being soluble in water to the extent of about 1.5 percent and in mineral oil to the extent of about 1.1 percent. This valuable property makes such compounds highly useful as antimicrobial agents for preserving cosmetic cream formulations. Effective preservation of a cosmetic cream can be accomplished by incorporating from about 0.01 to about 1.5 percent, preferably from about 0.1 to about 1.0 percent, of such compounds therewith. The preparation of a typical cosmetic base cream utilizing 5-bromo-2- methyl-5-nitro-l , 3-dioxane at 0.1 percent as a preservative is exemplified in Example 5.

Example 5 Seven and one-half kilograms of a non-ionic surfactant cosmetic base cream are prepared as follows: Add to a first suitable container, Phase I - Mineral oil, heavy 1,875 g.

Cetyl alcohol 300 g.

White wax 450 g.

Lanolin, anhydrous 225 g.

Sorbitan monosterate 300 g.

Polyoxyethylene (20) sorbitan monosterate 450 g.

Heat Phase I to 80°C. with continuous stirring Add to a second suitable container, Phase II - Purified water 3,750 ml.

Heat Phase II to 80°C.

Add Phase I to Phase II with continuous stirring.

Remove heat and allow lot to cool to 45°C. with continuous stirring.

Add to a third suitable container, Phase III - Polyethylene glycol 200 93.7 g. 5-bromo-2-meth l-5- nitro-1 , 3-dioxane 7.5 g.

Heat to 45°C. to dissolve with stirring.

Add Phase III to the lot at 45°C.

Mix well with continuous stirring.

Q. S. lot to 7.5 kg. with: Purified water 200 ml.

Cool to 37 °C. with continuous stirring.

In another embodiment of this invention the compound 5-bromo-2 , 2-dimethyl-5-nitro-l , 3-dioxane is an effective antimicrobial, useful for incorporation into such compositions as cosmetics and pharmaceuticals as a preservative. In addition, this useful compound is effective as an antimicrobial in such diverse compositions as adhesives, paints, both oil and water based, particularly latex, detergents, soaps, toilet, laundry, industrial, and others, shampoos, cutting oils, and antiseptic and sanitizing chemicals.

The compound 5-bromo-2 , 2-dimethyl-5-nitro-l , 3-dioxane can be prepared from contacting the 2-bromo-2-nitro-propane-1 , 3-diol of Preparation 1 described above with acetone. Example 6, details this preparation.

Example 6 To a 100 ml. 3-necked flask equipped with magnetic stirring was added 20 g. (0.1 mole) of 2-bromo-2-nitro-propane 1, 3-diol and 30 ml. (0.5 mole) of acetone. After solution was complete, the temperature was 15°C. Then 13 ml. (0.1 mole) of boron trifluoride etherate was added to the reaction mixture from a dropping funnel over a period of about 2 minutes. The temperature rose to 47°C. and then dropped to 35°C. over a period of 10 minutes.

The reaction mixture was then poured into 150 ml. of a saturated sodium bicarbonate solution and stirred for 15 minutes. The solids were filtered and washed with 200 ml. acetone, dried and an IR showed a reaction had occurred. About 18 g. of crude material was dissolved in 150 ml. of hot hexane and filtered. On cooling and standing overnight 9.0 g. (40% yield) of 5-bromo-2 , 2-dimethyl- 5-nitro-l , 3-dioxane was obtained as pure white needles.

An NMR and IR confirmed the structure. An elemental analysis disclosed the following percentage composition: C: calc, 30.02; found 29.94; H: calc, 4.20; found 4.26; N: calc. 5.83; found 6.05; Br: calc. 33.29; found 33.50; The antimicrobial activities of 5-nitro-2,2-dimethyl-5-nitro-l , 3-dioxane (Compound F) were determined concurrently with 5-bromo-2-methyl-5-nitro-l , 3-dioxane (Compound A) , and 5-bromo-5-nitro-l , 3-dioxane (Compound B) against the same six organisms shown in Table I. Compound A was clearly superior to Compound B, and Compound F showed an effectiveness similar to Compound B. The tests were in vitro determinations utilizing agar plates containing the active compound at 10, 25 and 50 meg. per ml. of agar. The organisms, at concentrations of 10^ organisms per milliliter, were streaked on the solidified agar. The plates were incubated for 24 hours and the presence or absence of growth noted. The minimum inhibitory concentration (MIC) was determined as the lowest active compound concentration in the agar where no growth occurred . Table X shows the results of this test.

X I 03 TABLE X In Vitro Antimicrobial Activity Minimum Inhibitory Concentration, meg. /ml. whe Pseudomonas Streptococcus Staphylococcus Esche aeruginosa faecalis aureus co Compound A <10 <10 <10 <1 Compound B 25 <10 25 <1 Compound F 50 25 25 25 I Useful compounds of the formula 3 wherein is methyl, ethyl, n-propyl, or isopropyl are effective antimicrobials for the prevention of the growth of microorganisms selected from the group of gram-positive, gram-negative bacteria and fungi. The growth of such micro-ogranisms can be prevented by contacting said microorganisms with an amount of such compounds effective to prevent such growth. Effective amounts of such compounds will range from as little as about 0.01 percent to about 2.0 percent by weight of the composition to which such compounds are added, preferably from about 0.1 percent to about 1.0 percent.

Typical of such compositions and the concentration of such useful compounds incorporated therein are the diverse products outlined in Examples 7-13.

Examples 7-13 Antimicrobial Solution: 95% SD3A Alcohol 50 parts Water, deionized 49.5 parts 5-Bromo-2 , 2-dimethyl- 5-nitro-l , 3-dioxane 0.5 part Antimicrobial Ointments: Polyethylene glycol 300 49.5 parts Polyethylene glycol 1500 49.5 parts 5-Bromo-5-nitro-2-n-propyl 1.0 part 1, 3-dioxane Antimicrobial Powder: Talcum, U.S.P 99 parts 5-Bromo-2-methyl-5-nitro-l , 3-dioxane 1 part Shampoo : Sodium laurylsulfate 40 parts Coconut fatty acid diethanolamide 6 parts Water, deionized 53 parts 5-Bromo-2-ethyl-5-nitro-l , 3-dioxane 1 part Antimicrobial Soap: Coconut oil glycerides, sodium salt 60 parts Tallow glycerides, sodium salt 39 parts 5-Bromo-2-methyl-5-nitro-l , 3-dioxane 1 part Antimicrobial Cleaning Composition; Fatty alcohol sulfate (sodium sulfate) 25 parts Sodium carbonate 7 parts Sodium sulfate 15 parts Trisodium phosphate 40 parts Pentasodium amino- trimethylenephosphate 10 parts Carboxymethylcellulo 1 part 5-Bromo-2 , 2-dimethyl 5-nitro-l , 3-dioxane 2 parts Antifungal Latex Paint: Polyvinyl acetate, emulsified 20 parts Water, deionized 78 parts 5-Bromo-2-ethyl-5-nitro- 1 , 3-dioxane 2 parts Other antimicrobial applications and uses of the useful compounds of this invention will be readily recognized by those skilled in the art. The preceding specific examples are illustrative of the practice of this invention and are to be understood as imposing no limitation on the spirit of the invention or the scope of the claims thereto.

Claims (1)

1. The method of claim Θ wherein the growth of a cosmetic The method of claims or wherein said compound is employed at a concentration from percent to The method of claims 6 or 7 wherein said compound is employed at a concentration of percent to A method for the prevention of the growth of organisms substantially as hereinbefore Antimicrobial compositions substantially as hereinbefore insufficientOCRQuality