Method of combatting microorganisms employing substituted oxazolines

A method of combatting microorganisms by applying to them or to their habitat an oxazoline represented by the formula ##STR1## where R and R.sup.1 can be methyl, ethyl or hydroxymethyl and can be the same or different; X is H.sub.2 or (--CH.sub.2 OH).sub.2 and R.sup.2 is alkyl of 4 to 16 carbon atoms.

BACKGROUND OF THE INVENTION 
This invention relates to a method of combatting microorganisms. In a 
particular aspect, this invention relates to a method of combatting 
microorganisms by the use of a member of the class of substituted 
oxazolines. 
H. L. Wehrmeister, in U.S. Pat. No. 3,509,260 disclosed that oxazolines 
wherein X in the formula below is H.sub.2 and R.sup.2 is the terminally 
unsaturated decene radical were effective bactericides and fungicides. 
Such compounds have many advantages. They contain no halogens and are of a 
very low order of toxicity to warm-blooded animals; they readily hydrolyze 
with rupture of the ring in the presence of an acid, so such compounds are 
non-persistent. Because of these properties they do not constitute a 
threat to the user nor to wildlife that might encounter them. There is 
however a continuing need for additional anti-microbials, especially those 
of the oxazoline class. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a method of combatting 
microorganisms. 
It is another object of this invention to provide a method of combatting 
microorganisms using a substituted oxazoline. 
Other objects of this invention will be apparent to those skilled in the 
art from the disclosure herein. 
It is the discovery of this invention to provide a method of combatting 
microorganisms by applying to them or to their habitat an oxazoline 
represented by the formula 
##STR2## 
where R and R.sup.1 can be methyl, ethyl or hydroxymethyl and can be the 
same or different, X is H.sub.2 or (--CH.sub.2 OH).sub.2 and R.sup.2 is an 
alkyl group of 4 to 16 carbon atoms.

DETAILED DISCUSSION 
The compounds used in the practice of this invention are known in the art. 
Compounds wherein X is (--CH.sub.2 OH).sub.2 were disclosed by H. L. 
Wehrmeister in U.S. Pat. No. 3,523,123, which is incorporated herein by 
reference. Compounds wherein X is H.sub.2 are old in the art. A good 
description for their preparation is described by R. F. Purcell in U.S. 
Pat. No. 3,336,145, which is also incorporated. herein by reference. 
The oxazoline preferred for the practice of this invention depends to a 
considerable degree on the particular organism to be combatted, since 
there is a surprising degree of selectivity. Generally, however, those 
oxazolines wherein X is (--CH.sub.2 OH).sub.2, R and R.sup.1 are each 
--CH.sub.2 OH and R.sup.2 is alkyl of from 8 to 14 carbon atoms are broad 
spectrum anti-microbials. However those wherein X is (--CH.sub.2 
OH).sub.2, R and R.sup.1 are each CH.sub.3 and R.sup.2 is 10 or 12 are 
also very effective. When X is H.sub.2 and R and R.sup.1 are methyl, the 
compound wherein R.sup.2 is alkyl of 10 carbon atoms is also a preferred 
oxazoline. 
The preferred oxazolines accordingly include but are not limited to: 
2-[1,1 -bis(hydroxymethyl)undecyl]-4,4-dimethyl-2-oxazoline 
2-[1,1-bis(hydroxymethyl)tridecyl]-4,4-dimethyl-2-oxazoline 
2-[1,1-bis(hydroxymethyl)nonyl]-4,4-bis(hydroxymethyl)-2-oxazoline 
2-[1,1-bis(hydroxymethyl)undecyl]-4,4-bis(hydroxymethyl)-2-oxazoline 
2-[1,1-bis(hydroxymethyl)tridecyl]-4,4-bis(hydroxymethyl)-2-oxazoline 
2[1,1-bis(hydroxymethyl)pentadecyl]-4,4-bis(hydroxymethyl)-2-oxazoline. 
2-undecyl-4,4-dimethyl-2-oxazoline. 
The compounds useful in the practice of this invention are generally 
effective to combat the growth of bacteria or fungi at low concentrations, 
e.g. 10 ppm. There is of course no upper limit to the amount that can be 
used but generally they become uneconomical above about 5000 ppm and 
accordingly a use concentration of 10-5000 ppm is contemplated. Generally, 
however, a concentration between 100 and 2000 ppm is preferred and a 
concentration of 500-1000 ppm is particularly preferred. 
Most of the oxazolines wherein X is (--CH.sub.2 OH).sub.2 are conveniently 
applied to the environment inhabited by microorganisms as an aqueous 
solution or dispersion. They are particularly effective in aqueous systems 
such as starch adhesives and solutions, drilling muds for the petroleum 
industry and in water-dilutable cutting oils based on petroleum 
hydrocarbons. 
These oxazolines, especially those wherein X is H.sub.2, are also soluble 
in, e.g., alcohols, ketones and most other organic solvents, including 
hydrocarbons. Solutions of the water-insoluble oxazolines in such solvents 
can be used in substantially non-aqueous or 2-phase systems when desired. 
The method of combatting microoganisms of this invention comprises 
application of the anti-microbial oxazolines of this invention to a 
substratum infested with the microorganisms to be combatted or to a 
substratum to be protected from infestation with the microorganisms. The 
term substratum as used herein is intended to mean the environment or 
medium upon which an organism grows and includes both animate and 
inanimate matter, such as animal and vegetable, living or dead, and the 
soil. The term microorganisms as used herein is intended to include 
bacteria and fungi but not algae, viruses, protozoa, etc. The term 
anti-microbial as used herein is intended to include the terms 
bactericidal, bacteriostatic, fungicidal and fungistatic. No attempt has 
been made to determine if the products actually cause the death of the 
organism or merely prevent their growth. 
The anti-microbial oxazolines of this invention can be used without 
dilution for the control of a wide variety of organisms. Preferably, 
however, they are used in a dispersed form in a suitable extending agent. 
The term "dispersed" is used herein in the widest possible sense. When the 
anti-microbial agents of this invention are said to be dispersed, it can 
mean that the particles of the anti-microbial agents are molecular in the 
form of a true solution in a suitable organic solvent. It can also mean 
that the particles are colloidal in size and distributed throughout a 
liquid phase in the form of particles held in suspension by wetting 
agents. The term also includes particles which are distributed in a 
semi-solid viscous carrier such as petrolatum or soap or other ointment 
base in which they may be actually dissolved in the semi-solid or held in 
suspension in the Semi-solid with the aid of suitable wetting or 
emulsifying agents. The term "dispersed" also means that the particles may 
be mixed with and distributed throughout a solid carrier providing a 
mixture in particulate form, e.g. pellets, granules, powders, or dusts. 
The term "dispersed" also includes mixtures which are suitable for use as 
aerosols including solutions, suspensions, or emulsions of the 
anti-microbial oxazolines of this invention in a carrier such as the 
chlorofluoroalkanes which boil below room temperature at atmospheric 
pressure. 
The term "extending agent" as used herein includes any and all of those 
substances in which the anti-microbial oxazolines of this invention are 
dispersed. It includes, therefore, the solvents of a true solution, the 
liquid phase of suspensions, emulsions or aerosols, the semisolid carrier 
of ointments and the solid phase of particulate solids, e.g. pellets, 
granules, dusts and powders. 
Usually it is preferred to supply these oxazolines as a concentrate such as 
a spray base or a wettable powder, i.e., a particulate solid base in such 
form that it can be easily mixed with water or a solid extender (e.g. 
powdered clay or talc) or other low-cost material available at the point 
of use. In such a concentrate, the oxazoline generally will be present in 
a concentration of 5 to 95 percent by weight. The remainder can be any one 
or more of the well-known adjuvants, such as a surface active agent (e.g. 
a detergent, soap, or other emulsifying or wetting agent) clays, solvents 
diluents, carrier media, adhesives, spreading agents, humectants, and the 
like. 
When the anti-microbial oxazolines of this invention are to be used in the 
form of aerosols, it is convenient to dissolve them in a suitable solvent 
and disperse the resulting solution in the aerosol propellant, i.e., 
dimethyl ether, propane, dichlorodifluoromethane or other 
chlorofluoroalkane. 
The anti-microbial oxazolines of this invention are preferably supplied to 
the microorganisms or to their environment in the form of emulsions or 
suspensions. Emulsions or suspensions are prepared by dispersing one or 
more of the oxazolines of this invention in water with the aid of a 
surface active agent. The anti-microbial oxazolines can be emulsified 
directly or they can first be dissolved in an organic solvent and then 
emulsified. The term "surface active agent" includes the various 
"emulsifying agents", "dispersing agent", "wetting agents" and "spreading 
agents" that can be mixed with the oxazolines of this invention in order 
to obtain a dispersion of the oxazolines in water. These surface active 
agents include the well-known anionic, cationic, or non-ionic surface 
active agents. In general, the water-soluble non-ionic surface active 
agents are preferred. 
The anti-microbial oxazolines of this invention can be dispersed by 
suitable methods (e.g., tumbling or grinding) in solid extending agents 
and supplied to the organisms' environment in particulate form. Solid 
extending agents include both inorganic and organic materials. Inorganic 
materials include tricalcium phosphate, calcium carbonate, kaolin, bole, 
kieselguhr, talc, bentonite, fuller's earth, pyrophillite diatomaceous 
earth, calcined magnesia, volcanic ash, sulfur and the like. Organic 
materials include powdered cork, powdered wood, and powdered nut shells. 
The preferred solid extending agents are the adsorbent clays, e.g., 
bentonite. These mixtures can be used for anti-microbial purposes in the 
dry form, or by addition of water-soluble surface active agents the dry 
particulate solids can be rendered wettable by water so as to obtain 
stable aqueous dispersions or suspensions suitable for use as sprays. 
For some purposes the anti-microbial oxazolines of this invention can be 
advantageously dispersed in a semi-solid extending agent such as 
petrolatum or soap (e.g., the sodium salt of a fatty acid) with or without 
the aid of solubility promoters and/or surface active agents. 
The dispersions described above can be used as such in combatting 
microorganisms or they can be formulated in a concentrated form suitable 
for mixing with other extending agents. A useful concentrate is a mixture 
of one or more anti-microbial oxazolines of this invention with a 
water-soluble surface active agent in the weight proportions of 0.1 to 15 
parts of surface active agent with sufficient of the anti-microbial 
oxazoline of this invention to make 100 parts by weight. Such a 
concentrate can be readily made into a spray for combatting microorganisms 
by diluting with water. An example of such a concentrate is a mixture of 
95 parts by weight of oxazoline and 5 parts by weight of water-soluble 
non-ionic surface active agent such as polyoxyethylene derivative of 
sorbitan monolaurate. 
Another useful concentrate which can be readily made into a spray for 
combatting microorganisms is a solution (preferably as concentrated as 
possible) of one or more anti-microbial oxazolines of this invention in an 
organic solvent therefor, to form a liquid concentrate. Preferably a minor 
amount (e.g., 0.5 to 10 percent by weight of the weight of the oxazoline) 
of a water-soluble surface active agent is also dissolved therein. An 
example of such a concentrate is a solution of oxazoline in acetone 
containing a water-polyoxyethylene glycol non-ionic surface active agent 
and a water-soluble alkylaryl sulfonate anionic surface active agent. 
The preferred surface active agents which can be employed in preparing the 
emulsifiable, wettable or dispersible compositions of this invention 
include the anionic and non-ionic surface active agents. The preferred 
anionic surface active agents are the well-known water-soluble alkali 
metal alkylaryl sulfonates, e.g., sodium dodecylbenzene sulfonate. The 
preferred non-ionic surface active agents are the water-soluble 
polyoxyethylene derivatives of the mono-higher fatty acid esters of 
hexitol anhydrides such as mannitan or sorbitan. 
In contolling or combatting microorganisms the oxazolines of this invention 
are supplied to the organisms or to their environment in a lethal or toxic 
amount. This can be done by dispersing one or more of the oxazolines or a 
composition containing it, in, on or over an environment or substratum 
infested with, or to be protected from, the microorganisms. The oxazoline 
or composition containing it can be dispersed in any conventional method 
which permits contact between the organisms and the anti-microbial agents 
of this invention. Conventional methods include power dusters, boom and 
hand sprayers, and spray dusters. For subsurface application to the soil 
such dispersing can be carried out by simply mixing the oxazoline as is or 
compositions containing one or more of them with the soil or by applying a 
liquid solution of the oxazoline to accomplish subsurface penetration and 
impregnation therein. 
The invention will be better understood with reference to the following 
examples. The examples are intended only to illustrate the invention and 
it is not intended that the invention be limited thereby. 
EXAMPLE 1 
2-Pentyl-4,4-bis(hydroxymethyl)-2-oxazoline was prepared by reacting 
caproic acid with 2-amino-2-methyl-1-propanol according to the method of 
Purcell, U.S. Pat. No. 3,336,145. This product was then condensed with 
formaldehyde in a 1:2 mole ratio, respectively, according to the method of 
Wehrmeister, U.S. Pat. No. 3,523,123. There was obtained 
2-[1,1-bis(hydroxymethyl)butyl]-4,4-bis(hydroxymethyl)-2-oxazoline. It was 
tested for anti-bacterial and anti-fungal activity against nine bacteria 
(4 Gram positive and 5 Gram negative) and eight fungi (6 molds and 2 
yeasts). These organisms are listed in Table 1 wherein each of them is 
assigned a number which identifies it in Table 3. Results are reported as 
minimum inhibitory concentration, which is the range between the highest 
concentration which permits growth and the lowest concentration which 
prevents growth. These ranges are listed in Table 2. They increase 
exponentially and each range is identified by an alphabetical letter from 
A to H. Because of uncontrollable variables, such as the vigor of the 
organism, the data are reproducible to about plus or minus one range. The 
results obtained by the use of the oxazoline of this example and of 
examples 2-12 are given in Table 3. The results show that the oxazoline of 
example 1 is effective in combatting at least some organisms in 
concentrations as low as 250 ppm. 
Table 1 
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IDENTIFYING 
NUMBER 
ORGANISMS IN TABLE 3 
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Bacteria 
Bacillus subtilis 1 
Staphylococcus aureus 2 
Streptococcus faecalis 3 
Sarcina lutea 4 
Escherichia coli 5 
Aerobacter aerogenes 6 
Pseudomonas aeruginosa 7 
Salmonella typhii 8 
Desulfovibrio aestaurii 9 
Fungi 
Cladosphorium herbarum 10 
Cephalosporium species 11 
Trichophyton mentagrophytes 
12 
Aspergillus niger 13 
Aureobasidium pullulans 14 
Fusarium moniliforme 15 
Sacchromyces cerevisiae 16 
Candida albicans 17 
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Table 2 
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MINIMUM INHIBITORY IDENTIFIED IN 
RANGE, ppm TABLE 3 AS 
______________________________________ 
&lt;33 A 
33-65 B 
65-125 C 
125-250 D 
250-500 E 
500-1000 F 
1000-2000 G 
&gt;2000 H 
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EXAMPLES 2-12 
The experiment of example 1 was repeated in all essential details except 
that various oxazolines were substituted for the oxazoline of example 1. 
The oxazolines are represented by the formula in Table 4 and the 
substituents R, R.sup.1 and R.sup.2 are identified. In Table 4 are listed 
the lowest concentration of oxazoline which prevented growth of at least 
one organism. 
3 Table 3 
##STR3## 
Inhibitory Properties of Oxazolines Oxazoline Activity Range Against 
Microorganism Ex. Bacteria Fungi No. R R.sup.1 R.sup.2 1 2 3 4 5 6 7 
8 9 10 11 12 13 14 15 16 17 
1 CH.sub.3 CH.sub.3 C.sub.4 H.sub.9 F F G F F D F F D G E D G G -- D 
H 2 CH.sub.3 CH.sub.3 C.sub.8 H.sub.17 F E E E F -- F F E D B -- E F F 
B E 3 CH.sub.3 CH.sub.3 C.sub.10 H.sub.21 A A A A F B G F E D A -- F G 
-- A H 4 CH.sub.3 CH.sub.3 C.sub.12 H.sub.25 C C D A G A G G A G A D G F 
H A H 5 CH.sub.3 CH.sub.3 C.sub.14 H.sub.29 G F G E F D F F F F D E F F 
G E H 5A CH.sub.3 CH.sub.3 C.sub.16 H.sub.33 G G F E G F G G G G F -- G 
H F D H 6 CH.sub.2 OH CH.sub.2 OH C.sub.4 H.sub.9 F F F E G -- G E E F E 
D G G -- D H 7 CH.sub.2 OH CH.sub.2 OH C.sub.6 H.sub.13 D D C C E E F E 
C E B D F F C -- G 8 CH.sub.2 OH CH.sub.2 OH C.sub.8 H.sub.17 A-B A-C 
A.sup.2* A.sup.2 F.sup.2 A.sup.2 F-G F.sup.2 E.sup.2 B-C B.sup.2 B-C 
E.sup.2 E.sup.2 E A-C E-F 9 CH.sub.2 OH CH.sub.2 OH C.sub.10 H.sub.21 A 
B C A F A G E D C A B E D D A B 10 CH.sub.2 OH CH.sub.2 OH C.sub.12 
H.sub.25 A-B A-D A-B A.sup.2 G-H B-D H F-G F-G D-E A.sup.2 D-E F-G F-H H 
A.sup.2 H.sup.2 11 CH.sub.2 OH CH.sub.2 OH C.sub.14 H.sub.29 A A A A G 
-- H H F F B -- G H G A H 12 CH.sub.2 OH CH.sub.2 OH C.sub.16 H.sub.33 G 
G B A H C H H D E B D H G A C H 
*The superscript signifies duplicate results. 
Table 4 
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CONCENTRATION PREVENTING 
OXAZOLINE OF GROWTH OF AT LEAST 
EXAMPLE NO. ONE ORGANISM, PPM 
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2 65 
3 &lt;33 
4 &lt;33 
5 250 
5A 500 
6 250 
7 65 
8 &lt;33 
9 &lt;33 
10 &lt;33 
11 &lt;33 
12 &lt;33 
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EXAMPLE 13-14 
The experiment of example 1 was repeated in all essential details except 
that oxazolines wherein X is H.sub.2 were used. The results, which are 
given in Table 5, show that the oxazoline of example 13 is effective 
against several organisms at a concentration less than 33 ppm and the 
oxazoline of example 14 is effective against at least one organism at a 
concentration of 65 ppm. The substituents R, R.sup.1 and R.sup.2 are 
identified in Table 5. 
Table 5 
__________________________________________________________________________ 
##STR4## 
Inhibitory Properties of Oxazolines 
Activity Range Against Microorganism 
Ex. Oxazoline Bacteria Fungi 
No. R R.sup.1 
R.sup.2 
1 2 3 4 5 6 7 8 9 10 
11 
12 
13 
14 
15 
16 
17 
__________________________________________________________________________ 
13 CH.sub.3 
CH.sub.3 
C.sub.10 H.sub.21 
A A A A E B H H E C A A H H -- 
A H 
14 CH.sub.2 OH 
CH.sub.2 OH 
C.sub.12 H.sub.25 
F F E -- 
H -- 
H H G E C -- 
H H H B 
H 
__________________________________________________________________________ 
examples 15-16 
the experiment of example 1 is repeated in all essential details except 
that oxazolines having the following substituents are substituted for the 
oxazoline of example 1. In each case, X is (--CH.sub.2 OH).sub.2. 
______________________________________ 
Example R R.sup.1 R.sup.2 
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15 CH.sub.3 CH.sub.2 OH 
C.sub.12 H.sub.25 
16 C.sub.2 H.sub.5 
CH.sub.2 OH 
C.sub.14 H.sub.29 
17 H C.sub.2 H.sub.5 
C.sub.14 H.sub.29 
______________________________________ 
The compounds are inhibitory to most microorganisms at a concentration of 
1000 ppm. 
EXAMPLE 17 
A cutting oil emulsion is prepared according to the following formula: 
______________________________________ 
Light mineral oil 20 parts 
Water 76.5 
Oxazoline of Example 1 
0.5 
Mixed C.sub.18 fatty acids 
3 
100 
______________________________________ 
The emulsion remains free from microbial contamination when used as a 
cutting oil.