JPS5913513B2 - Shinkitsu Fuenki Kagobutsu no Seizouhou - Google Patents

Description

Detailed Description of the Invention The present invention is based on the general formula (■) R_' R_□)CH=N((■) 20 (wherein, R_ is a hydrogen atom, a lower alkyl group, a lower alkoxy group, or a halogen atom). The present invention relates to a method for producing a novel Schiff base compound represented by the following formula: (represents a hydrogen atom or a dialkylamino group).

5 More specifically, the general formula (I) 7,R_□2)CH2shell(oR_,)2(I) (in the formula,
R_ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, or a halogen atom, and R_ represents a lower alkyl group or a phenyl group.

) and a nitrosobenzene compound represented by the general formula (■) (where k represents a hydrogen atom or a dialkylamino group) in an organic in solvent,
The present invention relates to a method for producing a novel Schiff base compound represented by the above general formula () by reacting it in the presence of a basic substance.

Dou (in the expression (),
R1 means the same as in general formula (1),
R represents an aromatic monovalent residue. ) Therefore, the novel Schiff base compound of the general formula () according to the present invention has not been known at all.

The reason for this is that it is generally extremely difficult to obtain 2-formylallyloxazoles (2), which are normally used as raw materials for synthesizing these Schiff base compounds. (In the formula, R means the same as in general formula (1).

) As a result of intensive studies to overcome the difficulties involved in the synthesis of the general formula (), the present inventors have discovered that the benzoxazolylmethanephosphonic acid ester compound represented by the general formula (1) and the general formula ( ) By reacting the compound with a nitrosobenzene compound represented by the formula (), they succeeded in obtaining the desired new Schiff base compound represented by the general formula () easily and in high yield.

Examples of the novel citrus base compounds represented by the general formula ( The general formula (
) are useful as starting materials for chemical products such as dyes and fluorescent brighteners.

For example, as shown in reaction formula (1) below, various arylooxazolyl ethylenes of general formula (V) that easily react with active methylene compounds such as general formula () and are important as fluorescent whitening agents. It is possible to lead to compounds. Therefore,
The method of the present invention is of extremely high industrial value. Benzoxazol-2-ylmethylene-4'dimethylaminoaniline, 5-methylbenzoxazol-2-ylmethyleneaniline, 5-methylbenzoxazol-2-ylmethylene-45dimethylaminoaniline, 6-methylbenzoxazole-2- ylmethyleneaniline, 5-ethylbenzoxazol-2-ylmethyleneaniline, 5-tert-butylbenzoxazole-2-ylmethyleneaniline, 5-methoxybenzoxazole-2-ylmethyleneaniline, 5-chlorobenzoxazole-2- Ilmethyleneaniline.

The benzoxazolylmethanephosphonic acid ester compound of the general formula (1) used as a raw material for producing the novel Schiff base compound having the general formula ( - After the halomethyloxazole compound is reacted with an excess amount of phosphite triester by heating under reflux in a nitrogen stream, the excess amount of phosphite triester is distilled off, and further distilled under reduced pressure if necessary. Examples include: diethyl benzoxazole-2-ylmethanephosphonate, diethyl 5-methylbenzoxazole-2-ylmethanephosphonate, 5-methylbenzoxazole-2- Dimethyl ylmethanephosphonate, diethyl 6-methylbenzoxazol-2-ylmethanephosphonate, 5-ethylbenzoxazole-2-
Diethyl ylmethanephosphonate, 5-n-n-propylbenzoxazole-2-ylmethanephosphonate, diphenyl 5-isopropylbenzoxazol-2-ylmethanephosphonate, 5-n-n-butylbenzoxazol-2-ylmethanephosphonate, diethyl methanephosphonate, 5 Diethyl tertiary-butylbenzoxazole-2-ylmethanephosphonate, 5-methoxybenzoxazole-2
-diethyl methanephosphonate, di-n-butyl 6-methoxybenzoxazol-2-ylmethanephosphonate, diethyl 5-ethoxybenzoxazol-2-ylmethanephosphonate, dimethyl 5-chlorobenzoxazol-2ylmethanephosphonate, diphenyl 6-chlorobenzoxazol-2-ylmethanephosphonate,
Diethyl 5-bromobenzoxazole-2ylmethanephosphonate, and among the raw materials, examples of nitrosobenzene compounds represented by the general formula () include the following: nitrosobenzene, 4-N-N- Dimethylaminonitrosobenzene, 4-N-N-diethylaminonitrosobenzene.

The basic substance used in the production method of the present invention is an alkali metal, an alkaline earth metal, or a hydroxide, oxide, alcoholade, hydride, or amidide of these metals, such as sodium hydroxide, Examples include potassium hydroxide, sodium oxide, sodium methylate, sodium ethylate, sodium hydride, sodium amide, metallic sodium, and metallic potassium.

In addition, reaction solvents include aliphatic and alicyclic alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and cyclohexanol; benzene, toluene,
Aromatic/alicyclic hydrocarbons such as ethylbenzene, xylene, cyclohexane, chlorobenzene, dichlorobenzene, or alkylated or halogenated products thereof;
Ethers such as diethyl ether, dioxane, tetrahydrofuran; N-N-dimethylformamide, N-
Examples include dialkylcarboxylic acid amides or dialkylsulfonamides such as N-dimethylacetamide and dimethylsulfoxide, and these may be used alone or in combination of two or more.

To carry out the method of the present invention, raw materials of general formulas () and () are taken in approximately equimolar ratios, and 3 of the total amount is
In an organic solvent of 0 to 100 times (by weight), in the presence of the above basic substance in an amount of 0.8 gram equivalent or more, preferably 1.0 to 2.0 gram equivalent, O to 100
The reaction is carried out at a temperature in the temperature range of 5°C to 40°C. The time required for the reaction is 10 minutes to 3 hours,
The target product can be obtained in extremely good yield. In carrying out the reaction, the order of charging the raw materials is arbitrary, and addition thereof in portions is also possible. At the start of the reaction, the raw materials are generally dissolved. As the reaction progresses, the reaction product usually precipitates as crystals, which are filtered out after the reaction is complete. Furthermore, if necessary, crystals of the reaction product can be precipitated more completely by cooling the reaction-completed liquid, distilling off the solvent from the reaction-completed liquid, or injecting the reaction-completed liquid into ice water. I can do it. Next, the details of the method of the present invention will be explained by way of examples.

Example 1 4-dimethylaminonitrosobenzene 15.07 was dissolved in 75 ml of methanol, and while stirring while keeping the temperature below 10°C, 26.8 f of diethyl benzoxazole 2-ylmethanephosphonate and 3.0 g of metal sodium were added thereto. 57
A solution prepared by dissolving .

The precipitated crystals were collected by straining, washed with methanol and water, and dried to give benzoxazol-2-ylmethylene-4'
-dimethylaminoaniline 24.47 is obtained. After recrystallization from ethanol, it exhibits a melting point of 166-166.5°C.
Benzoxazole-2- used as a raw material for this synthesis
Diethyl ylmethanephosphonate is obtained by the condensation reaction of 2-aminophenol and chloroacetyl chloride.
- Obtained as a pale yellow liquid by reacting chloromethylbenzoxazole with an excess amount of triethyl phosphite under reduced pressure in a nitrogen stream, followed by distillation under reduced pressure, with a boiling point of 0.09 mmHg under reduced pressure. 148~150'
C, and the refractive index (n is also 0) is 1.5169.

Example 2 10.7 y of nitrosobenzene was added to 5 y of methanol.
Dissolve in 0 ml and keep at 10℃ or less while stirring.
Into this were added 28.27 g of diethyl 5-methylbenzoxazol-2-ylmethanephosphonate and 3.7 g of sodium metal.
57 in 50 mj of methanol was added dropwise, and after the dropwise addition, the mixture was stirred at room temperature for 30 minutes.

The reaction solution was poured into 200 ml of ice water while stirring to sufficiently precipitate crystals.
23.6y of ylmethyleneaniline is obtained. When recrystallized from n-hexane, it has a melting point of 141-142°C.a Diethyl 5-methylbenzoxazolelylmethanephosphonate used as a raw material for this synthesis is 2-amino-4
-Methylphenol and chloroacetyl chloride? The 2-chloromethyl 5-methylbenzoxazole obtained by the condensation reaction of 5-methylbenzoxazole was reacted with excess triethyl ryleite under heating under reflux in a nitrogen stream, and then distilled under reduced pressure to obtain a pale yellow liquid. The boiling point was 0.05 mw! H
It exhibits a temperature of 139-140°C under reduced pressure of g, and the refractive index (n is also 0
) indicates 1,520.

Example 3 15.07 ml of 4-dimethylaminonitrosobenzene was dissolved in 75 ml of methanol, and 5-methylbenzoxazole-2-
A solution prepared by dissolving 28.2I17 of diethyl ylmethane sulfonate and 3.5f1 of sodium metal in 50ml of methanol was added dropwise, and after the dropwise addition, the mixture was stirred at room temperature for 2 hours.

The precipitated crystals were collected by straining, washed with methanol and water, and then dried to obtain 23.27 of 5-methylbenzoxazol-2-ylmethylene-4'-dimethylaminoaniline. Melting point 183.5-184℃ after recrystallization from ethanol
shows. Example 4 The same treatment was carried out using diethyl 5-methoxybenzoxazol-2-ylmethanephosphonate (29.87%) instead of diethyl 5-methylbenzoxazol-2-ylmethanephosphonate in Example 2. , yielding 23.77 g of pale yellow 5-methoxybenzoxazol-2-ylmethyleneaniline.

After recrystallization from ethanol, it exhibits a melting point of 128-129°C. Diethyl 5-methoxybenzoxazol-2-ylmethanephosphonate used as a raw material for this synthesis was
-2-chloromethyl-5 obtained by condensation reaction of amino-4-methoxyphenol and chloroacetyl chloride
-Methoxybenzoxazole is reacted with an excess amount of triethyl phosphite by heating under reflux in a nitrogen stream, and then the excess triethyl phosphite is distilled off under reduced pressure. Obtained as a brown-yellow oily residue. .

Example 5 27.6f7 of dimethyl 5-chlorobenzoxazol-2-ylmethanephosphonate was dissolved in 100ml of N.N-dimethylformamide, 10.77ml of nitrosobenzene was added, and the mixture was stirred while keeping the temperature below 10°C. An Alcolade solution consisting of 3.57 ml of sodium metal and 50 ml of methanol was added dropwise into the solution, and after the addition, the mixture was stirred at room temperature for 1 hour.

While cooling the reaction solution to below 10° C., 150 ml of water is added dropwise to sufficiently precipitate crystals. The crystals are collected, washed with methanol and water, and dried to yield 25.27 g of 5-chlorobenzoxazol-2-ylmethyleneaniline.
When recrystallized from benzene, it exhibits a melting point of 174-175°C. Dimethyl 5-chlorobenzoxazol-2-ylmethanephosphonate used as a raw material for this synthesis was obtained by the condensation reaction of 2-amino-4-chlorophenol and chloroacetyl chloride. Benzoxazole is reacted with an excess amount of trimethyl phosphite by heating under reflux in a nitrogen stream, and then the excess trimethyl phosphite is distilled off under reduced pressure to obtain a brown-yellow oily residue.

Claims (1)

[Claims] 1 General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R
represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, or a halogen atom, and R_1 represents a lower alkyl group or a phenyl group. ) and the general formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (wherein R' represents a hydrogen atom or a dialkylamino group) By reacting a nitrosobenzene compound represented by the following in an organic solvent in the presence of a basic substance, the general formula (III) ▲ has mathematical formulas, chemical formulas, tables, etc. ▼ (III) (in the formula, R and R'
means the same as in general formulas (I) and (II). ) A method for producing a novel Schiff base compound represented by