KR800000431B1 - Preparing process for 3-isoxazolyl urea derivatives - Google Patents

Abstract

3-Isoxazolyl urea derivs.(I, R =H, alkyl or aryl; R2,R3 = H, alkyl, alkenyl, alkinyl, aralkyl, aryl, alkoxy or alkylthio; X = H, alkyl or halogen), useful as herbicides or algicides, were prepd. by reaction of isoxyano-3-isoxazolyl ester(II, R is given) and amine(III, R2 and R3 are given). Thus, 1.15 g N-methylbutylamine was added to 1.99 g isocyano-5-t-butyl-3-isoxazolyl ester in 120ml benzene, and refluxed for 3 hr to give 2.73 g 1-butyl-l- methyl-3-(5-t-butyl- 3-isoxazolyl)urea.

Description

Method for preparing 3-isoxazolyl urea derivative

The present invention relates to a process for the preparation of isoxazolyl derivatives of the general formula (I).

Where

R represents hydrogen, an alkyl group or an aryl group,

R ² and R ³ represent hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group, an alkoxy group or an alkylthio group, and R ² and R ³ are connected directly or indirectly by containing a hetero atom. A nitrogen-containing ring may be formed,

X represents hydrogen, an alkyl group or a halogen, R and X may be connected to form an alkylene group, and the alkyl group, aralkyl group and aryl group may have one or more substituents selected from halogen, alkyl group, nitro group and hydroxy group. .

The isoxazolyl urea derivative of the general formula (I) according to the present invention reacts the isocyanic acid 3-isoxazolyl ester of the following general formula (II) with an amine of the following general formula (III) as shown in the following reaction formula: Can be prepared.

Where

R, R ² , R ³ and X are as described above.

When the terms defined above are supplemented, the alkyl group includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. Examples of the alkynyl group include vinyl, aryl, propenyl, butenyl, butadienyl, and cyclohexenyl. Examples of the alkynyl group include ethynyl, propenyl and butynyl, and aralkyl groups include benzyl and phenethyl. Examples of the alkoxy group include methoxy, ethoxy, propoxy and butoxy, and alkylthio groups include methylthio, ethylthio, propylthio, butylthio, pentylthio, and the like. Examples thereof include chlorine, fluorine, bromine and iodine, and examples of the alkylene group include tetramethylene and pantamethylene.

The method of the present invention is a reaction of isocyanic acid or isocyanic acid ester with amine, and suitable inert solvents (e.g., benzene, toluene, dioxane, diglyme, dimethylform) at room temperature or under cooling or heating by conventional methods. Amide). In order to perform reaction smoothly, you may add a basic catalyst (for example, pyridine and triethylamine).

Another raw material isocyanate ester (II) is derived from the corresponding carboxylic acid (IV) or amine (VI) as shown in the following formula.

Where

R and X are as described above.

The 3-isoxazolylurea derivative (I) thus obtained is useful as a novel compound immer, herbicide or algae.

The method of the present invention is described in detail below as examples.

Example 1

1.99 g of isocyanate 5-t-butyl-3-isoxazolyl ester is suspended in 120 ml of benzene, and 1.15 g of N-methylbutylamine is added thereto and refluxed for 3 hours. After cooling, the solvent is distilled off from the reaction solution, and the residue is obtained by thin layer chromatography on silica gel, obtaining 2.73 g of 1-butyl-1-methyl-3- (5-t-butyl-3-isoxazolyl) urea. This product was recrystallized with hexane to obtain a crystal having a melting point of 65.5 to 66.5 ° C. Yield 89.8%

[Examples 2 to 73]

The reaction was carried out in the same manner as in Example 66, using the following starting material (II) to obtain the corresponding target material (I).

Example 74

1.54 g of 3-methylamino-5-t-butylisoxazole is dissolved in 50 ml of toluene, hydrogen chloride gas is introduced at room temperature for 30 minutes, stirred for 1 hour, and then distilled under reduced pressure to remove excess hydrogen chloride gas. 30 ml of toluene is added and phosgene gas is introduced at 50 to 70 ° C for 3.5 hours. The mixed solution is allowed to stand overnight at room temperature, and toluene is distilled off at a bath temperature of 40 to 45 ° C. 20 ml of pyridine and 1 g of dimethylamine are added to the residue, which is stirred for 6 hours at 50 ° C. The pyridine is distilled off under reduced pressure from the reaction solution, 20 ml of water is added to the residue, acidified with hydrochloric acid, and extracted with chloroform. The chloroform layer was concentrated under reduced pressure, and the residue was purified by column chromatography on silica gel to give 1,1,3-trimethyl-3- (5-t-butyl-3-isoxazolyl) as a crystal having a melting point of 90.0 to 91.0 ° C. Got urea.

Claims (1)

A process for the preparation of 3-isoxazolyl urea derivatives of the following general formula (I) characterized by reacting an isocyanic acid 3-isoxazolyl ester of the following general formula (II) with an amine of the following general formula (III):

Where R represents hydrogen, an alkyl group or an aryl group, R ² and R ³ represent hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group, an alkoxy group or an alkylthio group, and R ² and R ³ may be directly connected or indirectly contain a hetero atom to be contained. May summon a summons, X represents hydrogen, an alkyl group or a halogen, R and X may be connected to form an alkylene group, and the alkyl group, aralkyl group and aryl group may have one or more substituents selected from halogen, alkyl group, nitro group and hydroxy group. .