JPS632554B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2-methoxy-6-methylaminopyridine.

2-methoxy-6-methylaminopyridine is
It is a novel compound and is useful as an intermediate for pharmaceuticals and agricultural chemicals.

The present inventors first reacted 2,6-dihalopyridine with memethiamine to form a solid 2-halo-6-
We proposed a method for producing 2-methoxy-6-methylaminopyridine by obtaining methylaminopyridine and then reacting solid 2-halo-6-methylaminopyridine with methanol in the presence of an alkali metal hydroxide.

As a result of further intensive study, the inventor found that 2.6-
The present invention was completed by discovering that 2-methoxy-6-methylaminopyridine can be produced using dihalopyridine as a starting material without separating 2-halo-6-methylaminopyridine as a solid intermediate.

That is, the present invention is characterized by reacting 2,6-dihalopyridine and methylamine in water, separating an aqueous layer and an organic layer when heated, and reacting the organic layer with methanol in the presence of an alkali metal hydroxide. A method for producing -methoxy-6-methylaminopyridine is provided.

In the method of the present invention, methylamine is 2.6
-Used at least 2 times the mole, usually 3 to 4 times the mole, relative to the dihalopyridine.

The reaction is usually carried out at 80-160°C, preferably 100-130°C.
Conducted at °C.

The reaction time is influenced by the molar ratio of methylamine to 2,6-dihalopyridine used as raw materials, reaction temperature, etc., but is usually 1 to 10 hours. For example, if the reaction is carried out at 130°C using 3 times the mole of methylamine relative to 2,6-dichloropyridine, the reaction can be completed in about 3 hours.

After the above reaction, the reaction solution is transferred to a separator while hot and separated into an aqueous layer and an organic layer, and only the organic layer is separated. Methanol and an alkali metal hydroxide are added to the organic layer, and the temperature is usually about 160 to about 200°C, preferably about 120 to about 200°C.
Heat to about 180℃.

Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, etc., and are used in an amount of 1 or more moles, preferably about 2 to about 3 moles, relative to 2,6-dihalopyridine.

The heating time may be changed depending on the heating temperature, the amount of alkali metal hydroxide used, and other conditions. Usually about 1 to about 10 hours is sufficient.

By using this method, 2,6-dihalopyridine is used as a starting material, but 2-6-dihalopyridine is used as an intermediate.
2-methoxy-6-methylaminopyridine can be produced without removing halo-6-methylaminopyridine as a solid.

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

Example 1 2.6- in a 200ml electromagnetic stirring autoclave
37.0 g of dichloropyridine and 75.0 g of a 40% methylamine aqueous solution were taken and reacted at 130°C for 3 hours.
After the reaction was completed, the autoclave was opened, the reaction solution was transferred to a separatory funnel, and the organic layer was separated.

Next, 70 ml of methanol and 20 g of sodium hydroxide were added to the organic layer, and the mixture was heated at 160° C. for 4 hours.

After heating, the autoclave was cooled, the contents were taken out, and the solids were filtered. Then, methanol was distilled off from the liquid, water was added to the residue, and the mixture was extracted with ether. The ether extract was dried over anhydrous magnesium sulfate, and after distilling off the ether, it was distilled under reduced pressure to a boiling point of 88-92.
21.7 g of 2-methoxy-6-methylaminopyridine was obtained at a temperature of 5 mmHg.

Infrared absorption spectrum (NaCl) 3420 (-NH), 2950 (C-H), 1600, 1475, Nuclear magnetic resonance absorption spectrum ( _CCl4 , internal standard
TMS) δ 2.86(d)ppm(3H) δ 3.85(s)ppm(3H) δ 4.40ppm(1H) δ 5.84(d)ppm(1H) δ 5.94(d)ppm(1H) δ 7.12(t)ppm (1H) The results of elemental analysis (as C ₇ H ₁₀ N ₂ O) were as follows.

C H N O Analytical value (%) 60.73 7.25 20.35 11.67 Theoretical value (%) 60.85 7.30 20.27 11.58 Molecular weight by GC-MS 138 Example 2 55.0 g of 2,6-dibromopyridine, 40 % methylamine aqueous solution 50.3
g was taken and reacted at 100°C for 3 hours. After the reaction was completed, the autoclave was opened, the reaction solution was transferred to a separatory funnel, and the organic layer was separated.

Next, 80 ml of methanol and 26 g of potassium hydroxide were added to the organic layer, and the mixture was heated at 150°C for 5 hours.

Thereafter, 2-methoxy-
21.2 g of 6-methylaminopyridine was obtained.

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

2-methoxy- which is the target substance of the method of the present invention
1.38 g of 6-methylaminopyridine and the same amount of anhydrous potassium carbonate were stirred in 20 ml of acetone at room temperature, 2.23 g of 2-naphthyl chlorothioformate dissolved in 20 ml of acetone was added, and after 30 minutes the reaction mixture was extracted with benzene and washed with water. , dried and recrystallized to give 0-2-naphthyl N-(6-methoxy-2-pyridyl)-N
2.73 g of -methyl-thiocarbamate were obtained.

Melting point 95.5-97℃ Elemental analysis value (as C ₁₈ H ₁₆ N ₂ O ₂ S) C H N Analysis value (%) 66.48 4.90 8.79 Theoretical value (%) 66.65 4.97 8.64 Paddy soil was placed in a porcelain pot with a diameter of 9 cm. , After watering and plowing, weed seeds are sown on the soil surface layer, 2
Paddy rice seedlings (variety, Nipponbare) in the leaf stage are planted at a depth of 1 cm.
Two plants were planted. The next day, the water was flooded to a depth of 2 cm, and the water level reached 0-
A wettable powder containing 10% of 2-naphthyl N-(6-methoxy-2-pyridyl)-N-methylthiocarbamate was diluted in 10 ml of water per pot and dropped onto the water surface. Thereafter, the plants were left in a greenhouse and three weeks after the chemical treatment, the herbicidal effect and the effect on paddy rice were investigated. As a result, the test chemical amount of 125g/10a caused no chemical damage to paddy rice seedlings, and 100% control of grasshopper, Japanese cyperus, bulrush, Japanese cypress, and staghorn grass was achieved.

Claims (1)

[Claims] 1 2-Methoxy, which is characterized by reacting 2,6-dihalopyridine and methylamine in water, separating an aqueous layer and an organic layer when heated, and reacting the organic layer with methanol in the presence of an alkali metal hydroxide. −
Method for producing 6-methylaminopyridine.