Antimicrobial dihalonitromethylisoxazoles

This invention concerns novel dihalonitromethyl heterocyclic ring compounds which are useful in the control of a variety of harmful microorganisms.
The nitration of active methylene compounds containing an activating group such as an ester, ketone or cyano group has been previously described. See Feuer et al., J. Am. Chem. Soc., 78, 4364 (1956), Ibid., 81, 5826 (1959), J. Org. Chem., 29, 939 (1964), Ibid., 31, 3152 (1966), Ibid., 34, 991 (1969); and Klager, Ibid., 20, 646 (1955).
In addition, p-anisylnitromethane and its ring nitro derivatives have been prepared by Zalukajevs et al., Latvijas P.S.R. Zinatnu Akad. Vestis, 109 (1956). The same auther also prepared .alpha.-naphthylnitromethane, J. Gen. Chem. U.S.S.R., 26, 657 (1956).
Primary or secondary nitro compounds form nitronate salts which react with bromine to form bromonitro compounds. In the case of .alpha.-nitrocyclic ketones, cleavage can occur upon bromination. See Feuer et al., J. Org. Chem., 29, 939 (1964), Ibid., 33, 3622 (1968), Ibid., 34, 991 (1969). The preparation of halo derivatives of various nitromethyl heterocycles was recently disclosed by Feuer et al., J. Org. Chem., 37, 3662 (1972). Zalukajevs et al. prepared the halo derivatives of 2-nitromethylquinoline, Zhur. Obshchei Khim., 28, 483 (1958).
There is no suggestion in any of the above-described publications that any of the compounds possess antimicrobial activity.
Belgian Patent No. 702,570 discloses 1-aryl-2-nitrohaloethanes useful in the control of bacteria, fungi and algae in water and aqueous compositions. Gum et al., U.S. Pats. Nos. 3,703,515 and 3,754,042, disclose dihalonitromethylsutstituted quinoxalines and cycloalkanes, respectively, which are said to have antimicrobial activity.
SUMMARY
This invention provides to the art a class of novel dihalonitromethyl heterocyclic ring compounds which possess strong activity against bacteria, fungi, and protozoa. Such compounds are those having the formula
R -- CX.sub.2 NO.sub.2
wherein X represents chloro or bromo;
R represents ##SPC1##
E represents oxygen or sulfur;
Ar combined with the two carbon atoms to which it is attached forms phenyl or naphthyl;
Each of the R.sup.1 groups independently represents C.sub.1 -C.sub.3 alkyl or phenyl;
n represents 0-2 when R.sup.1 represents C.sub.1 -C.sub.3 alkyl;
n represents 0 or 1 when R.sup.1 represents phenyl;
R.sup.2 represents hydrogen, C.sub.1 -C.sub.3 alkyl, or phenyl;
R.sup.3 represents hydrogen or C.sub.1 -C.sub.3 alkyl;
R.sup.4 represents C.sub.1 -C.sub.3 alkyl.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The compounds of this invention are characterized by a dihalonitromethyl group attached to a heterocyclic ring, which may be substituted with lower alkyl or phenyl groups.
The term C.sub.1 -C.sub.3 alkyl is used in the formula above to refer to alkyl groups such as methyl, ethyl, n-propyl and isopropyl.
The term Ar is used in the structures above to indicate that the scope of this invention includes fused-ring compounds wherein a thiazole or oxazole ring is fused to a phenyl or naphthyl ring to form compounds wherein the dihalonitromethyl group is 2-substituted on rings such as benzoxazole and naphthothiazole.
While the generic formula above describes the compounds unambiguously, the following compounds are named to assure that those skilled in the art understand the invention.
2-dichloronitromethyl-1,3,4-oxadiazole
2-dibromonitromethyl-5-isopropyl-1,3,4-oxadiazole
2-dibromonitromethyl-5-phenyl-1,3,4-oxadiazole
2-dichloronitromethyl-1,3,4-thiadiazole
2-dichloronitromethyl-5-phenyl-1,3,4-thiadiazole
2-dichloronitromethyl-5-methyl-1,3,4-thiadiazole
2-dibromonitromethyl-2-oxazoline
2-dibromonitromethyl-4,5-diethyl-2-oxazoline
2-dibromonitromethyl-5-isopropyl-2-oxazoline
2-dichloronitromethyl-4-phenyl-2-oxazoline
2-dichloronitromethyl-5-ethyl-2-thiazoline
2-dichloronitromethyl-2-thiazoline 2-dibromonitromethyl-4,5-dimethyl-2-thiazoline
2-dichloronitromethyl-4-phenyl-2-thiazoline
2-dibromonitromethylthiazole
2-dibromonitromethyl-4,5-dimethylthiazole
2-dichloronitromethyl-4-ethylthiazole
2-dibromonitromethyl-5-phenylthiazole
2-dichloronitromethyloxazole
2-dichloronitromethyl-4-phenyloxazole
2-dichloronitromethyl-4-propyloxazole
2-dibromonitromethyl-4,5-diethyloxazole 3-dichloronitromethyl-5-phenylisoxazole
5-dichloronitromethyl-3,4-dimethylisoxazole
5-dibromonitromethyl-3-isopropylisoxazole
2-dibromonitromethylbenzothiazole
2-dibromonitromethyl-5-ethylbenzothiazole
2-dichloronitromethyl-4,6-dimethylbenzothiazole
2-dibromonitromethyl-6-phenylbenzothiazole
2-dibromonitromethyl-4-phenylbenzoxazole
2-dichloronitromethyl-7-ethylbenzoxazole
2-dibromonitromethylbenzoxazole
2-dibromonitromethyl-5,7-diethylbenzoxazole
2-dibromonitromethylnaphtho[1,2-d]thiazole
2-dichloronitromethyl-5-phenylnaphtho[2,1-d]thiazole
2-dichloronitromethyl-4,6-diethylnaphtho[2,1-d]thiazole
2-dichloronitromethyl-8-ethylnaphtho[1,2-d]thiazole
2-dichloronitromethyl18-methylnaphtho[1,2-d]oxazole
2-dichloronitromethyl-6,9-dipropylnaphtho[2,1d]oxazole
2-dichloronitromethylnaphtho[1,2-d]oxazole
2-dibromonitromethyl-5-phenylnaphtho[2,1-d]oxazole
A preferred subgenus of this invention comprises compounds wherein the R group contains a ring oxygen atom. The preferred individual compounds of the invention are 3-dibromonitromethyl-5-phenylisoxazole, 2-dibromonitromethylbenzoxazole, 3-dichloronitromethyl-5-phenylisoxazole, 5-dichloronitromethyl-3-methylisoxazole, and 2-dichloronitromethyl-2-oxazoline.
The compounds of this invention are easily prepared in a two-step synthesis from methyl-substituted heterocyclic ring compounds having the desired R.sup.1, R.sup.2, R.sup.3, or R.sup.4 substituents. Such compounds are commercially available or can be prepared using known procedures in the chemical literature.
The first step of the synthesis is the formation of a nitronate salt, having the structure
R - CH = NO.sub.2 .sup.-M.sup.+
In the formula, R represents the heterocyclic ring described above, and M represents alkali metal, preferably potassium.
Nitronate salts are formed by the procedure described by Feuer et al., J. Am. Chem Soc., 91, 1856 (1969). A methyl heterocycle is treated with an alkali metal amide in liquid ammonia, followed by n-propyl nitrate as the nitrating agent. The reaction is conducted at a temperature from -75.degree. to -30.degree.C. and is generally complete in less than one-half hour. For a discussion of possible variations in the formation of nitronate salts, including solvent effects and the different bases that may be employed, see Feuer et al., J. Am. Chem. Soc., 78, 4364 (1956). One skilled in the art will also recognize that other nitrating agents, such as amyl nitrate, can be used in the formation of nitronate salts.
The nitronate salt is converted to the dihalonitromethyl compounds of the present invention by treatment with a halogenating reagent. The dichloro compounds can be prepared from the nitronate salts by treating with an agent such as potassium hypochlorite at temperatures between -10.degree.C. and 20.degree.C. The corresponding dibromo compounds are best prepared by treatment with bromine in potassium hydroxide solution under similar conditions. The use of a two-fold excess of the aqueous halogenating reagent forms the dihalonitro compound, usually in less than one hour.
The preparative examples below illustrate the methods by which the compounds are made, and are not intended to limit the scope of the invention in any way. The first example shows the synthesis of a typical nitronate salt.

EXAMPLE 1
potassium 3-methyl-5-phenylisoxazolenitronate
Liquid ammonia, 250 ml., was placed in a flask equipped with a mechanical stirrer, thermometer, and Dry Ice condenser. With the temperature kept below -33.degree.C. by external cooling using a Dry ice-acetone bath, a catalytic amount of ferric nitrate monohydrate was added, followed by 5.9 g. of metallic potassium. The mixture was stirred at temperatures below -33.degree.C. until the mixture formed a gray suspension. To the ammonia solution was then added 15.8 g. of 3-methyl-5-phenylisoxazole in 30 ml. of anhydrous ethyl ether, and the mixture was stirred at reflux (approximately -33.degree.C.) for 15 minutes more. the mixture was then cooled to -40.degree.C. to -50.degree.C., and 20.9 g. of n-propyl nitrate was added at such a rate as to control the temperature below -35.degree.C. After stirring for 30 minutes at -33.degree.C., the ammonia was allowed to evaporate and was replaced with 200 ml. of ethyl ether. The solid which formed was filtered, washed with ethyl ether, and dried under vacuum. The product, potassium 3-methyl-5-phenylisoxazolenitronate, was obtained in a sufficiently pure form to use in the following step without further purification. The yield was 20.9 g.
The intermediate nitronate salts are converted to the new dihalonitromethyl compounds by processes typified by the following example.
EXAMPLE 2
3-dibromonitromethyl-5-phenylisoxazole
A 5.9 g. portion of the nitronate salt made in Example 1 was dissolved in 45 ml. of water, and the solution was filtered. The solution was then added to a solution of 15.1 g. of KOH and 15.1 g. of bromine in 60 ml. of water at 0.degree.-5.degree.C. The reaction mixture was stirred for 1 hour at about 5.degree.-10.degree.C. during which time a precipitate formed. The solids were collected by filtration, washed with water and dried. The product was recrystallized from hexane, and identified by nuclear magnetic resonance analysis. The yield was 0.50 g. of 3-dibromonitromethyl-5-phenylisoxazole (I), m.p. 72.degree.-74.degree.C.
The following exemplary compounds were made by the processes of Examples 1 and 2 with small modifications which can readily be supplied by one skilled in the art.
2-dichloronitromethylnaphtho[2,1-d]thiazole (II), m.p. 114.degree.-116.degree.C.
2-dibromonitromethylbenzoxazole (III), m.p. 76.degree.-80.degree.C.
2-dibromonitromethylnaphtho[1,2-d]thiazole (IV), m.p. 116.degree.-117.degree.C.
2-dichloronitromethyl-5-methyl-1,3,4-thiadiazole (V), oil
2-dichloronitromethyl-4-methylthiazole (VI), oil
4-dibromonitromethyl-2-methylthiazole (VII), 95-95-98.degree.c.
5-dibromonitromethyl-3-methylisoxazole (VIII), m.p. 59.degree.-62.degree.C.
5-dichloronitromethyl-3-methylisoxazole (IX), oil
3-dichloronitromethyl-5-phenylisoxazole (X), m.p. 65.degree.-67.degree.C.
2-dichloronitromethyl-2-oxazoline (XI), oil
2-dichloronitromethylnaphtho[1,2-d]thiazole (XII), m.p. 108.degree.-112.degree.C.
2-dichloronitromethylbenzothiazole (XIII), m.p. 38.degree.38.degree.43.degree.C.
2-dichloronitromethylbenzoxazole (XIV), m.p. 41.degree.-45.degree.C.
2-dibromonitromethylbenzothiazole (XV), m.p. 71.degree.-73.degree.C.
2-dibromonitromethyl-5-methyl-1,3,4-thiadiazole (XVI), m.p. 76.degree.-72.degree.C.
2-dibromonitromethylnaphtho[2,1-d]thiazole (XVII), m.p. 129.degree.-130.degree.C.
2-dichloronitromethyl-2-thiazoline (XVIII), m.p. 58.degree.-62.degree.C.
2-dibromonitromethyl-2-oxazoline (XIX), m.p. 60.degree.-62.degree.C.
The compounds of the present invention are biocides in a broad sense. As the examples below indicate, the compounds kill or control microorganisms such as bacteria, fungi, protozoa, and algae, as well as some aquatic weeds. Those skilled in the art will appreciate that the biocidal properties of the compounds make them useful in many ways.
For example, the compounds can be added to bodies of water such as cooling towers and ponds, lagoons, lakes and the like for the control of aquatic weeds, algae, and slime-forming microorganisms. The control is brought about by adding an effective, economical amount such as from about 0.1 to about 100 ppm. of the compound to the water to be protected from aquatic organisms. It is often convenient to formulate the compound in an easily water-dispersible mixture before addition. Such formulations are known to the art, and comprise a finely divided powder, or a solution or suspension of the compound in a liquid such as water or an organic solvent, to which surfactants such as ethylene oxide adducts of nonylphenol and alkylbenzenesulfonates are often added to increase the dispersibiility of the mixture.
The compounds can also be added to such compositions as adhesives, inks, plasticizers, latices, polymers, resins, fuels, lubricants, soaps and detergents, cutting oils, and paints to prevent the growth of mold and the degradation of the products which results from attack by microorganisms.
The compounds can also be coated on or distributed through products such as textiles, paper and other cellulose products and may be impregnated into wood, wall paneling and plaster to protect such products from mold and decay caused by microbial infestation. The compounds are especially useful for the preservation of such products as cosmetic formulations.
The compounds are valuable disinfectants and sterilizing agents for surfaces such as floors, walls, hospital equipment, kitchen equipment and the like.
The compounds of this invention can be used to control microorganisms, especially fungi, growing on the skin and outer tissues of animals. The examples below show, for example, that the compounds are especially effective in the control of Candida tropicalis and Trichomonas vaginalis, both of which are important causes of vaginal infections. The compounds are used for the control of such infections by formulating them into ointments, creams and the like according to the usual pharmaceutical methods and applying them topically to the site of the infection.
The outstanding efficacy of the compounds against representative microorganisms is illustrated by the examples below.
EXAMPLE 3
in vitro agar dilution test
Bacteria and fungi in an agar medium were stamped on a plate to which one drop of a 100 .mu.g./ml. or a 10 .mu.g./ml. solution of the compound was surface applied. The agar plates were then incubated at 35.degree.C. for 12 hours, at which time the antibacterial activities were evaluated. The fungi were incubated at 25.degree.C. for an additional 60 hours before evaluation. The procedure was essentially that recommended in Acta Pathol. Microbiol. Scand. B., Suppl. 217, 11 (1971). A rating of 100 indicates that the compound prevented growth of the microbe at 100 .mu.g./ml. and 10 indicates prevention at the 10 .mu.g./ml. level. NT indicates the compound was not tested for activity against an organism, while a blank space indicates the compound was not active at the highest level tested (100 .mu.g./ml.).
__________________________________________________________________________Com- Staphylo- Streptocc- Proteus Salmonella Klebsiella- Klebsiella- Escherichia Pseudomonas C-476pound coccus us typhosa aerobacter sp. aerobacter sp. coli aeruginosa aureus faecalis KA14 KA17__________________________________________________________________________I 10 100 100 100 10 10 10 100 100II 10 10 10III 10 10 100 10 10 10 10 10 10VIIX 10 10 10 10 10 10 10 10 100XII 100 100XIII 100 100 100 100 100 100XIV 10 100 100 100 100 100 10 100 100XVIII 100 100 100 100 100 100 100 100__________________________________________________________________________Com- Salmon- Pseudomonas Erwinia Xanthomo- Candida Trichophyton Botrytis Cerato- Fusarium Verticill-pound ella solanacearum amylovora nas tropic- mentagrophy- cinerea cystis oxysporum ium typhi- phaseoli alis tes ulmi lycopersici albo-atrum murium__________________________________________________________________________I 10 10 100 10 100 10 10 10 100 10II 100 100 100 100III 10 10 10 10 10 10 100 100 10VII 100X 10 10 100 10 10 10 10 10 10 10XIIXIII 100 100 100 100 100 100 100 100XIV 100 100 100 100 10 10XVIII 100 100 100 100 100 10 100 100 100 100__________________________________________________________________________
Staphyloccus Staphyloccus Streptoccus Proteus Salmonella Klebsiella EnterobacterCompound aureus 3055 aureus 3074 faecalis X66 Morganii Pris typhosa SA12 pneumoniae Aerogenes__________________________________________________________________________ EB17IV 100 100 100 100 100 100 100V 100VI 100 100 100 100VIII 100 100 100 100 100 100 100IX 100 100 100 100 100 100 100XI 10 10 100 10 10 100 100XV 100 100 100 100 100 100 100XVI 100 100 100 100 100 100 100XVII 100 100 100 100 100 100 100XIX 100 100 100 100 100 100 100__________________________________________________________________________ Serratia Escherichia Citrobacter Pseudomonas Bordetella SalmonellaCompound marcescens SE3 coli EC14 freundii CF17 aeruginosa X239 bronchiseptica typhimurium__________________________________________________________________________IV 100 100 100 100 100 100V 100VI 100VIII 100 100 100 100 100 100IX 100 100 100 100 100XI 100 10 100 100 10 10XV 100 100 100 100 100 100XVI 100 100 100 100 100 100XVII 100 100 100 100 100 100XIX 100 100 100 100 100 100__________________________________________________________________________ Psuedomonas Erwinia Candida Trichophyton Aspergillis Ceratocystis Compound solanacearum X185 amylorora tropicalis A17 mentagrophyles 27 flavis ulmi__________________________________________________________________________ IV 100 100 100 100 100 100 V 100 100 VI 100 100 10 10 10 VIII 100 100 100 100 100 100 IX 100 100 100 10 10 10 XI 100 10 10 100 100 10 XV 100 100 100 100 100 100 XVI 100 100 100 100 100 XVII 100 100 100 100 100 XIX 100 100 100 100 100 100__________________________________________________________________________
The example below reports representative results of testing the compounds in a slightly different in vitro test against a different group of microorganisms.
EXAMPLE 4
in vitro tube dilution test
The organisms against which the compounds were to be tested were grown in nutrient broth in test tubes under sterile conditions. One hundred .mu.g./ml. of the compound to be tested was added to a tube of broth, and the treated broth was serially diluted with untreated broth in which the culture had been inoculated. The tubes were observed, and the results for each compound were recorded as the lowest concentration, in micrograms per milliliter, in which the compound prevented the growth of the microorganism.
__________________________________________________________________________ Staphylococcus Streptococcus Mycoplasma Escherichia Salmonella PseudomonasCompound sp. 1130 sp. 80 Vibrio coli gallisepticum coli dublin sp.__________________________________________________________________________I 50 50 50 25 >50 >50 >50III 50 50 25 25 >50 >50 50IV >50 >50 >50 50 >50 >50 >50V >50 50 50 25 >50 >50 >50VI 12.5 12.5 25 6.25 50 25 >50VII >50 >50 50 >50 >50 >50 >50VIII >50 >50 >50 50 >50 >50 >50IX 25 25 <.78 25 50 50 >50X 12.5 6.25 25 12.5 25 25 50XI 12.5 25 6.25 6.25 25 25 >50XII 25 12.5 3.12 25 >50 >50 >50XIII 50 25 25 12.5 50 50 50XIV 25 25 12.5 50 50 50 >50XV >50 >50 >50 >50 >50 >50 >50XVI >50 >50 50 50 >50 >50 >50XVII >50 >50 50 50 >50 >50 >50XVIII 12.5 6.25 6.25 6.25 12.5 12.5 50XIX >50 >50 50 25 >50 >50 50__________________________________________________________________________ Pasteurella P. multocida Mycoplasma Compound multocida turkey isolate Bordetella syroviae M. hyorhinis M. granularum__________________________________________________________________________ I 25 25 50 50 50 25 III 50 50 50 25 50 >50 IV 50 >50 50 25 25 50 V 50 50 50 25 >50 50 VI 12.5 6.25 50 12.5 25 12.5 VII >50 50 >50 50 50 50 VIII >50 >50 >50 50 50 >50 IX 12.5 3.12 50 50 25 X 3.12 3.12 12.5 12.5 50 6.25 XI 6.25 12.5 12.5 12.5 50 50 XII 12.5 25 25 12.5 25 12.5 XIII 25 25 50 25 50 25 XIV 12.5 12.5 25 12.5 50 25 XV >50 >50 >50 >50 >50 >50 XVI 50 50 >50 50 50 >50 XVII 50 >50 >50 50 50 >50 XVIII 3.12 6.25 12.5 12.5 25 6.25 XIX >50 >50 >50 50 50 50__________________________________________________________________________
A generally similar test was performed to evaluate the compounds against additional species of fungi.
EXAMPLE 5
in vitro antifungal test
Compound Trichophyton CandidaNo. mentagrophytes albicans______________________________________VI 0.2 .mu.g./ml. 2.0 .mu.g./ml.VIII >2.0 20XI 0.2 20XIII 0.02 0.2XIV 0.02 2.0XV 0.002 20XVI >2.0 20XVIII 0.2 2.0XIX 2.0 20______________________________________
In a different antifungal test, the compounds to be tested were absorbed on paper discs, and the discs were laid on plates of fungus-infected agar medium. The results were reported as the last amount of compound per disc which produced a measurable inhibition of the fungus.
______________________________________Compound Trichophyton CandidaNo. mentagrophytes albicans______________________________________X 0.625 .mu.g./ml. 0.078 .mu.g./ml.______________________________________
Compounds of this invention were tested in vitro to determine their ability to control protozoa and algae. The examples below report representative results of such tests.
EXAMPLE 6
in vitro protozoa inhibition tests
The tests were run against four representative protozoa, Tetrahymena pyriformis (T), Ochromonas malhamensis (O), Euglena gracilis (E), and Trichomonas vaginalis (TV). The protozoa were grown in the laboratory in nutritive media. When a test was to be run, nutritive medium containing the test protozoa was mixed with sterile agar medium, and the mixed medium poured into plates.
Absorbent discs were treated with 0.02 ml. of a solution containing a known concentration of the compound to be tested. The concentrations used are indicated in the table below. The discs were placed on the surfaces of the protozoa-containing agar plates.
The plates were incubated for a time, and were then inspected to determine if the test compounds absorbed on the discs had inhibited the growth of the protozoa. Inhibition, if present, was measured as the diameter in millimeters of the zones of inhibition surrounding the discs.
The table below reports the zones of inhibition produced by representative compounds of this invention. The notation TR indicates that the compound gives a trace of inhibition. NT indicates that the compound was not tested against a given organism, and a blank space indicates that the compound was inactive.
______________________________________CompoundNo. Conc. T O E TV______________________________________I 2000 17 28 11 500 12 17 TR 125 TR 10III 2000 46 25 50 15 500 25 15 20 10 125 14 10 11IV 2000 25 25 23 11 500 12 14 10 125 TRV 2000 26 30 38 500 16 17 16 125 11 11 11VI 2000 17 19 22 500 TR 12 11X 2000 16 18 13 36 500 13 12 12 23 125 TR TR TR 15XI 2000 14XII 2000 10 17 500 TRXIII 2000 17 25 24 500 15 18 17 125 13 14 15XIV 2000 24 18 20 12 500 18 17 17 125 14 TR TRXV 2000 20 24 25 TR 500 12 11 10XVI 2000 16 18 28 11 500 12 TR 12 TRXVII 2000 26 38 14 500 12 18 TR 125 TRXVIII 2000 20 17 20 10 500 13 12 10 TR 125 12 10 TRXIX 2000 25 17 24 15 500 13 14 12 TR______________________________________
EXAMPLE 7
in vitro algae inhibition test
The activity of the compounds against a typical alga was determined by conducting a test, substantially identical to the test described above, against Chlorella vulgaris. Representative results are reported below.
______________________________________CompoundNo. Conc. Chlorella______________________________________I 2000 72 500 32 125 10III 2000 77 500 40 125 12IV 2000 39 500 19 125V 2000 26 500 13 125VI 2000 10 500X 2000 16 500 13 125 11XI 2000XII 2000 TR 500XIII 2000 21 500 15 125 TRXIV 2000 30 500 17 125 TRXV 2000 38 500 16XVI 2000 42 500 13XVII 2000 58 500 20 125XVIII 2000 42 500 23 125 10XIX 2000 18 500 11______________________________________
The tests reported below show the ability of the compounds of the invention to eradicate microorganisms established in a culture.
EXAMPLE 8
in vitro eradication test
Aqueous dispersions of 3-dibromonitromethyl-5-phenylisoxazole were inoculated to contain known concentrations of the organisms shown below. Viable organism counts, in organisms per milliliter, were made initially and after times of 25.degree.C. incubation shown in the table below. A count of less than 100 organisms per milliliter is regarded as equivalent to complete kill of the organism.
______________________________________0.5% of Compound Pseudomonas AspergillusDays aeruginosa niger______________________________________ 0 3.4 .times. 10.sup.6 6 .times. 10.sup.3 1 <100 <100 7 <100 <10028 <100 <100______________________________________
0.1% of Compound Pseudomonas AspergillusDays aeruginosa niger______________________________________ 0 6.4 .times. 10.sup.6 5 .times. 10.sup.3 1 <100 4 .times. 10.sup.3 7 <100 <10014 NT <10028 <100 <100______________________________________
Similar tests were performed with 3-dichloronitromethyl5-phenylisoxazole.
______________________________________0.5% of Compound Pseudomonas AspergillusDays aeruginosa niger______________________________________ 0 5.9 .times. 10.sup.6 1 .times. 10.sup.4 1 1.9 .times. 10.sup.5 2.7 .times. 10.sup.3 7 <100 <10014 <100 <10028 <100 <100______________________________________
A similar test, against a broader range of microorganisms, was performed with 3-dibromonitromethyl-5-phenylisoxazole as the test compound. In this test, the fungi were inoculated in Sabouraud dextrose agar, and the bacteria in soybean-casein medium. The test was otherwise similar to the test described immediately above.
__________________________________________________________________________0.05% of Compound Staphylococcus Escherichia Pseudomonas Candida Aspergillus StreptococcusDays aureus coli aeruginosa albicans niger faecalis__________________________________________________________________________ 0 4.3 .times. 10.sup.6 6.9 .times. 10.sup.6 4.5 .times. 10.sup.6 3.2 .times. 10.sup.6 3.2 .times. 10.sup.5 2.5 .times. 10.sup.6 1 <100 <100 <100 3.6 .times. 10.sup.5 3.9 .times. 10.sup.5 <100 7 <100 <100 <100 3.7 .times. 10.sup.4 4.4 .times. 10.sup.5 <10014 NT NT NT <100 1.7 .times. 10.sup.5 NT21 NT NT NT <100 7.5 .times. 10.sup.2 NT28 <100 <100 <100 <100 <100 <100__________________________________________________________________________
The compounds also kill or control many aquatic weeds. For example, hydrilla, coontail, and duckweed were controlled by adding 10 ppm. of 2-dibromonitromethyl-2-oxazoline to the water in which the weeds were growing. Similar weed control was produced by, for example, 3-dichloronitromethyl-5-phenylisoxazole and 2-dibromonitromethylbenzothiazole.

Antimicrobial dihalonitromethylisoxazoles

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