JPS6013762A - Preparation of 2-halo-6-methylaminopyridine - Google Patents

Abstract

NEW MATERIAL:2-Halo-6-methylaminopyridine of formula (X is Br or Cl). EXAMPLE:2-Chloro-6-methylaminopyridine. USE:Raw material of compounds useful as agricultural chemicals and pharmaceuticals, e.g. O-2-naphthyl N-(6-methoxy-2-pyridyl)-N-methylthiocarbamate (a herbicide). PREPARATION:The compound of formula can be produced in high yield by reacting 2,6-dihalopyridine with 1-1.5 times mole of methylamine in the presence of a dehydrohalogenation agent such as NaOH, Na2CO3, etc. if necessary in a solvent, at 60-180 deg.C for 3-15hr.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2-no-6-methylaminopyridine.

2-halo 6-methylaminopyridine indicates the structure. ) is a novel compound that is useful as an intermediate for substances that can be used in medicines, agricultural chemicals, etc.

The present inventors previously proposed a method for producing the compound of the present invention by reacting 26-dino lopyridine with methylamine.

When producing 2-hao-6-methylaminopyridine, if 2,6-cyhalobidine and methylamine are simply reacted, a hydrogen halide salt of methylamine will be produced as a by-product, so at least 2,6-di/ - Twice the theoretical amount of methylamine is required per mole of ropyridine, and in reality it is more than that.

The present inventors have carried out various tests and intensively studied methods for reducing the amount of methylamine used. the result,
The present invention was completed by discovering that the amount of methylamine used can be reduced to 1 to 1.5 times the mole by adding a dehydrohalogenation agent.

That is, the present invention provides a method for producing 2-halo-6-methylaminopyridine, which is characterized by reacting 2,6-cyhalopyridine and methylamine in the presence of a dehydrohalogenating agent.

Dehydrohalogenating agents used in the method of the present invention include bases such as alkali metal hydroxides, alkaline earth metal hydroxides, and alkali metal carbonates. and these bases to approximately Q for 2,6-valoviridine.
, 5 to about 2 times the mole amount.

A solvent can be used to facilitate the reaction.

As a solvent, 2,6-cyhalopyridine.

A material that does not react with methylamine or dehydrohalogenation reagent is selected. Since methylamine is available as an aqueous solution, it is usually convenient to use water.

The reaction is usually carried out at about 60 to about 180°C, preferably about 100°C.
Perform at ~150<0>C. The reaction time is closely related to the reaction temperature, the molar ratio of methylamine and 26-cyhalopyridine, etc. For example, when the reaction temperature is 130°C and the molar ratio of methylamine and '2,6-cyhalopyridine is t5, the reaction The time is about 5 hours, generally about 6 to about 1 hour.
It is 5 hours.

By using the method of the present invention, 2-chloro-6-methylaminopyridine can be produced in high yield even if the amount of dimethylamine used is reduced to 1 to 1.5 times the mole.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 2,6-cyclopyridine 6&69,40-thi-methylamine aqueous solution 41 in a 200 d electromagnetic stirring autoclave
．． 9g and 189g of sodium hydroxide were taken and reacted at 130°C for 7 hours.

After the reaction was completed, the autoclave was cooled, the contents were taken out, and the solids were collected by filtration to obtain 5a8 g of 2-chloro-6-methylaminopyridine.

The yield of 2-chloro-6-methylaminopyridine is 2.6
-9t7% based on dichloropyridine.

Melting point 615-64.5°C Infrared spectrum (KBr) ss 10 (-NH), 2950 (0-H), 15
95.1450° nuclear magnetic resonance absorption spectrum (CCl4
．． Internal standard TMS) δ 22-85 (d) pp 5H δ alo (a) # IH a &43 (d) I IH δ &40 1H δ zzs (t) I 1a Elemental analysis value (as 06H, OIN) OHN C! 1 Analysis value ←) 5 (L41 4.99 19.75 24
．． 87 theoretical value ←) 5 [L54 4.95 19.64
24.86 Molecular weight by QC-Mass 142 Comparative Example In the same reactor as Example 1, 26-cyclopyridine 6
&69.9 g of a 40% methylamine aqueous solution was taken and reacted at 130°C for 7 hours.

After the reaction was completed, the autoclave was cooled, the contents were taken out, and the solids were collected by filtration to obtain 35 qy of 2-chloro-6-methylaminopyridine.

The yield of 2-chloro-6-methylaminopyridine is z6-
It was 52.9% based on dichloropyridine.

Example 2 26-dipromopyridine 7 was added to the same reactor as Example 1.
1.19, 65.1 g of a 40% methylamine aqueous solution and 1 and 5 g of potassium hydroxide were taken and reacted at 120°C for 5 hours.

After the reaction was completed, the autoclave was cooled, the contents were taken out, and the solids were collected by filtration to obtain 52.79 g of 2-bromo-6-methylaminopyridine.

The yield of 2-promo-6-methylaminopyridine is 2.
It was 959% based on 6-dibromopyridine.

Melting point 63-64°C Infrared absorption spectrum (KBr) ss2o (-NH), 29so (c-H), 159
0.1440.141o(o)cPrrl nuclear magnetic resonance absorption spectrum (cDc4, internal standard TMS) δ 19
0(d)ppm 3H δ 5.30 1H δ t2s(a)y 1a δ &67(d) #11(δ z, 22(t)l IH elemental analysis value (as C!aH7Br4) CHN Br analysis value &b) 3a56 385 14.88 42L
91 theoretical value (a) 3a53 577 14.97 4
2.72 Molecular weight by GO-Mass 186 Example 3 In the same reaction apparatus as in Example 1, 59.29, 40% methylamine aqueous solution of 2.6-dichloropyridine was added 4 t9 g
Then, 253 g of sodium carbonate was taken and reacted at 150°C for 6 hours.

After the reaction was completed, the autoclave was cooled, the contents were taken out, and the solids were collected by filtration to obtain 51.69 g of 2-chloro-6-methylaminopyridine.

The yield of 2-chloro-6-methylaminopyridine is 2.
Based on 6-dichloropyridine, 9 [1! It was J.

Next, examples of compounds obtained from the compounds of the present invention and their use as herbicides will be shown.

2-Chloro-6-methylaminopyridine, which is the target substance of the process of the present invention, is reacted with sodium methoxide to obtain 2-chloro-6-methylaminopyridine (boiling point 88-9
This 1,389 was stirred in 20 mg of acetone with the same amount of anhydrous potassium carbonate, and 2-7-tylchlorothioformate 2.239 dissolved in 20 Wt of acetone was added and reacted after 60 minutes. Extract the mixture with benzene and wash with water.

Dry and recrystallize to obtain 0-2-naphthyl N-(6-medoxy-2-pyridyl)-N-methylthiocarbamate.2.
75g was obtained.

Melting point 95.5-97℃ Elemental analysis value (as 0, sH,, N, 0.S) Q HN Analysis value S) 6&42 4.89 a81 Theoretical value (S)
6 & 65 4.97 a642-promo 6-methylaminopyridine and sodium methoxide are reacted in the same manner to form 2-methoxy-6-methylaminopyridine, and 2-
Q-2-naphthyl N-(6-medoxy-2-pyridyl)-N-methylthiocarbamate can be obtained by reaction with naphthyl chlorotheoformate.

Fill a porcelain pot with a diameter of 9 ounces with paddy soil, add water and plow through the soil, sow weed seeds on the surface layer of the soil, and place two paddy rice seedlings (variety, Nipponbare) at the two-leaf stage at a depth of one sub, two plants and two plants. It was planted.

The next day, 2cIn of water was poured into the water and 0-2-naphthyl N-(
A wettable powder containing 10% of 6-medoxy (2-pyridyl)-M-methylthiocono(mate) was diluted in 10 d of water per pot and dropped onto the water surface.

Thereafter, the plants were left in a greenhouse, and 5 weeks after the chemical solution treatment, the herbicidal effect and the effect on paddy rice were investigated.

As a result, the test chemical amount of 125 g/10 a caused no phytotoxicity to paddy rice seedlings and controlled 100 plants of Japanese grasshopper, Japanese cypress, firefly, Japanese grasshopper, and Japanese grassweed.

Patent applicant: Toyo Soda Kogyo Co., Ltd.

Claims (1)

[Claims] 2. A method for producing 2-halo-6-methylaminopyridine, which comprises reacting 6-cyhalopyridine and methylamine in the presence of a dehydrohalogenating agent.