NO812579L - MICROBICID AGENT. - Google Patents

Description

The invention relates to microbicidal agents containing N-alkyl-2,3-dichloromaleimides.

From the U.S. patent no. 2,865,730 it is known that halogen-maleimides have herbicidal action. British patent no. 1,094,802 mentions the use of halogen-maleimides as growth substances.

It is also known (DE-OS 2,156,967 and U.S. Patent No. 3,734,927) that N-(p-fluorophenyl)-2,3-dichloromaleimide is an active substance against citrus scab. From Japan Kokai 73/39, 638, the use of N-(fluorophenyl)-2,3-dichloromaleinimides for combating Trichoderma viridei fungal cultures is known.

New microbicidal agents containing N-alkyl-2,3-dichloromaleimides with the formula have been found

in which

R"<*>" means an optionally substituted alkyl or cycloalkyl.

The new N-alkyl resp. -cycloalkyl-substituted di-chloromaleinimides have a surprisingly greater microbicidal effect than the corresponding N-phenyl-substituted compounds.

Alkyl is preferably a straight or branched hydrocarbon residue with 1-16 carbon atoms. Particularly preferred is a lower alkyl residue with up to approx. 6 carbon atoms. For example, the following alkyl residues should be mentioned: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl and isohexyl.

Cycloalkyl is preferably a cyclic hydrocarbon residue with 3-10 carbon atoms. Particular preference is given to the cyclopentyl and cyclohexyl residues.

As substituents of the residue R" there must be mentioned in microbicide agents usual substituents. For example, the following residues can be mentioned: halogen such as fluorine, chlorine, bromine and iodine (preferably fluorine and chlorine, thiocyanate, C^-C^-alcok- sy, C 1 -C 4 -alkylthio and phenyl.

As a preferred microbicidal agent with formula (I), mention must be made of N-alkyl-2,3-dichloromaleimide with formula

in which

R 2 means a lower alkyl, cyclopentyl or cyclohexyl residue.

The N-alkyl-2,3-dichloromaleinimides according to the invention can be prepared in a manner known per se (British patent 818-192). For example, amines with formula can

where in

R^ has the above meaning,

is reacted with dichloromaleic anhydride at elevated temperatures, for example 70 - 120°C in the presence of acids, for example glacial acetic acid or hydrochloric acid.

The N-alkyl-2,3-dichloromaleinimides according to the invention can preferably be used as active substances for combating microorganisms in technical materials.

Technical materials that must be protected using the active substances according to the invention against microbial change and destruction are, for example, adhesives, glue, paper and cardboard, textiles, leather, wood, coating agents, plaster, emulsions and plastic articles that can be attacked and/or destroyed by microorganisms. Within the framework of materials to be protected, parts of production facilities can also be mentioned, for example cooling water and cooling lubricant circuits, which can be affected by microorganisms.

Microorganisms that can cause a breakdown or a change in the technical materials are, for example, bacteria, fungi, yeast, algae, mucus and viruses. Preferably, the N-alkyl-2,3-dichloromaleinimides according to the invention are used against fungi, especially against wood-discoloring and wood-destroying fungi and molds.

For example, the following genera can be mentioned as microorganisms:

Alternaria, such as Alternaria tenuis,

Aspergillus, such as Aspergillus niger,

Chaetomium, as Chaetomium globosum,.

Coniophora, such as Coniophora cerebella,

Lentinus, as Lentinus tigrinus,

Penicillium, such as Penicillium glaucum,

Polyporus, such as Polyporus versicolor,

Pullularia, such as Pullularia pullulans,

Scerophoma, such as Sclerophoma pityophila, Trichoderma, such as Tr'ichoderma viride, Staphylococcus, such as Staphylococcus aureus.

Depending on the area of application, the N-alkyl-2,3-dichloromaleimides according to the invention can be transferred in the usual formulations such as solutions, emulsions, suspensions, powders, pastes and granules. These can be produced in a manner known per se, e.g. by mixing the active substances with a suspending agent of liquid solvent and/or solid carriers, possibly using surface-active agents such as emulsifiers and/or dispersing agents, as, for example, when using water suspending agents, organic solvents may possibly be used as co-solvents.

Liquid solvents of the active substances can e.g. be water, alcohol, for example lower aliphatic alcohol, preferably ethanol and isopropanol, and aromatic alcohols such as benzyl alcohol, liquid hydrocarbons sqm gasoline fractions, chlorinated hydrocarbons such as 1,2-dichloroethane.

Solid carriers that can be added during the production of the finished application forms of the active substance can be, for example, talc, diatomaceous earth, bentonite, kaolin, diatomaceous earth and synthetic rock flour.

Surfactants can be commercially available emulsifiers such as alkyl sulfonate, alkyl aryl sulfonates, aryl sulfonates, alkyl amide sulfonates, alkyl aryl polyether alcohols, polyoxyethylene fatty acid esters or dispersing agents such as lignin, methyl cellulose, polyoxyethylene polyoxypropylene block polymer.

The application form of the microbicidal agent according to the invention usually contains 0.1 - 95% by weight, preferably 0.5 - 90% by weight, of the N-alkyl-2,3-dichloromaleinimide according to the invention as active substance.

The effective amounts of substances required for the protection of technical materials can be varied within large areas. Usually they are in the range of 0.0001 - 5% by weight, preferably in the range of 0.01 - 2% by weight, referred to the total amount of the material to be protected.

The active substances according to the invention can be present in formulations mixed with other known active substances. For example, the following active substances should be mentioned: Benzimidazolyl methyl carbamate, tetramethyl thiuram disulphide, N-fluorodichloromethylthiophthalimide and N,N'-dimethyl-N'-phenyl-(N-fluorodichloromethylthio)-sulfamide.

A) Manufacturing example

To a solution of 334 g (2.0 mol) of dichloromaleic anhydride in 1400 ml of glacial acetic acid is added 146 g (2.0 mol) of n-butylamine dissolved in 300 ml of glacial acetic acid. After stirring for 2 hours at 80°C, it is allowed to cool and the reaction mixture is mixed with ice water. The precipitated yellowish crystals are filtered off, washed with water and dried. Yield: 390.0 g (88% of theoretical), melting point 37°C.

B) Determination of the minimum inhibitory concentration ( MHK); An agar made from beer wort and peptone is mixed with the active substance in concentrations of 0.1 mg/l to 2000 mg/l. After solidification of the agar, contamination takes place with the pure cultures of the test organisms listed in Table 1. After 2 weeks of storage at 28°C and 60 - 70% relative humidity, the MHK is determined. MHK is the lowest concentration of active substance at which the growth of the specified microbetype is inhibited. It is indicated in the following table 1.

Claims (4)

1. Microbicidal agent containing N-alkyl-2,3-dichloromaleimides with formula in which R" <*> " means optionally substituted alkyl or cycloalkyl. 2. Microbicidal agent according to claim 1, containing N-alkyl-2,3-dichloromaleinimides of formula where R 2 denotes a lower alkyl or cyclohexyl residue. 3. Use of microbicide agents according to claim 1 for the protection of technical materials. 4. Microbicidal agent according to claims 1 and 2 containing 0.1 - 55% by weight of N-alkyl-2,3-dichloromaleimide.