SU1657495A1 - Method for obtaining 3-ciano-4-methyl-5-chloro-6-hydroxypyridone- 2 - Google Patents

Abstract

The invention relates to heterocyclic substances, in particular the preparation of 3-cyano-4-methyl-5-chloro-6-hydroxy-pyridone-2 for the synthesis of 4-me-amides. Tyl-2,5,6-trichloronicotinic acid, which has fungicidal activity. The purpose of the invention is to create a new method of obtaining the specified product. The process is carried out by the reaction of 3-cyano-4-methyl-6-hydroxypyridone-2 with chlorine or sulfuryl chloride, followed by reduction of the obtained dione with zinc in alcohol or in a mixture of water and acetone or dioxane at their molar ratio of 1: 2. the target product is obtained with a yield of 77-98%. 1 hp Y) ly. § k /

Description

The invention relates to a method for producing 3-cyan-4-methyl-5-chloro-6hydroxypyridone-2 of the formula cr_ClyVCN 'noAgo which can be used as an intermediate for the synthesis of 4-methyl-2,5,6-trichloronicotinic acid amides, with fungicidal activity.

The aim of the invention is to develop a method for the preparation of 3-cyan-4-methyl ^- 5-chloro-6-hydroxypyridone-2, which can be used for the synthesis of compounds with a fungicidal effect.

Example 1. A mixture of 3.0 g (0.02 mol) of 3-cyan-4-methyl-6-hydroxypyridone-2, 3.38 g (0.025 mol) of sulfuryl chloride and 30 ml of dried carbon tetrachloride is heated at the boiling point for 1 hour. After cooling the reaction mass, the precipitate is separated, washed with carbon tetrachloride until neutral, dried. Obtain 4.0 g (91%) of 1-H-Z-cyan-4-methyl-

5,5-dichloropyrid-2,6-dione, mp = = 163-164 ° C. Mol.m. = 219.03.

Found,%: C 38.25; Η 1, 62; C1 32.23; N, 12.62.

C ₇ H ₄ C1 ₂ N _g O _g

Calculated,%: C 38.38; H, 1.84; C1, 32.37; N, 12.79.

1657495 A1

4.0 g (0.0183 mol) of 1-H-3-cyan-4methyl-5,5-dichloropyrid-2,6-dione are dissolved in 60 ml of ethanol and 2.34 g (0) are added in portions at room temperature with stirring. , 0366 mol) zinc dust. 5-10 minutes after the completion of zinc addition, the precipitate is filtered off by reprecipitation of potassium hydroxide solution from ΙΟΖ-ηογο. get rid of excess zinc, dried. 3.3 g (84Ζ) of zinc salt are obtained.

3-cyan-4-methyl-5-chloro-6-hydroxypyridone-2, mp > 400 ° С, mol.m.431.18, С ₁₄ Н _В С1 ^ N ^ O ^ Zn. The composition of the named zinc salt is confirmed by quantitative * determination of zinc by atomic absorption analysis.

Found, X: Zn ⁱ 1 45 mg / g.

Calculated: X: Zn ^x 148 mg / g. 2θ

The obtained zinc salt is dissolved in 100 ml of boiling water, the cooled solution is acidified with conc. HCl to pH> 1, the precipitate formed is filtered off, dried in vacuum at 110 ° C. Get 25

2.6 g ¢ 77/5) 3-cyan-4-methyl-5-chloro-6-hydroxypyridone-2, mp "248-249 ° C. Mol.m. = 184.59.

Found, X: C 44, £ 9; H 2.64 ;. C1 19.64; N, 15.58.

C ^ HgClNjOg, ^L

Calculated, X: C, 45.54; H 2.74; C1 19.20; N, 15.18.

I

Example 2. Through a suspension of 3.0 g (0.02 mol) of 3-cyan-4-methyl-6hydroxypyridone-2 in 40 ml of dry carbon tetrachloride, chlorine is bubbled at room temperature until the evolution of hydrogen chloride ceases. The precipitate is filtered off, washed on the filter with tetrachloride carbon until neutral, dried. 4.35 g of (99X) 1-H-3-cyan-4-methyl-5,5 5-dichloropyrid-2,6-dione are obtained, m.p. ^I 163164 ° C.

4.35 g (O, 0199 mol) l-H-3-cyan-

4-methyl-5,5-dichloropyrid-2,6-dione is dissolved in 40 ml of dioxane, 20 ml of water are added and at room temperature 2.50 g (0.0398 mol) of zinc dust are added in portions. Through

5-10 minutes after the addition of zinc, the precipitate is filtered off, reprecipitated from the lOZ KOH solution, then dissolved in 100 ml of boiling water, acidified with conc. HC1 to pH> 1. After separation of the precipitate and drying under vacuum at 110 ° C, 2.5 g (74 () of 3-cyan-4-methyl are obtained

5-chloro-6-hydroxypyridone-2, mp 248-249 ⁱⁿ S.

Example 3. A suspension of 5 g (0.0333 mol) of 3-cyan-4-methyl-b-hydroxypyridio-2 in 60 ml of dry carbon tetrachloride is cooled to -10 ° C and chlorine is passed through it, maintaining the temperature at -10 ° C. until the evolution of hydrogen chloride ceases. The precipitate is filtered off, washed with carbon tetrachloride, dried, and 7.2 g of (98Ζ) 1 ^- H-3-cyan-4-methyl-5,5-dichloropyrid-2,6-dione are obtained, m.p. = * 163 ~ 164 ^Q C.

Recovery of the latter is carried out as described in example 1 or 2.

The proposed compound can be used for the synthesis of substituted amides of 4-methyl-2,5,6-trichloronicotinic acid (by replacing the hydroxyl groups with chlorine and subsequent hydrolysis of the cyano group), which have fungicidal activity. They reduce the incidence of wheat brown rust by 74-82X when using a concentration of 0.1 X.

Thus, the proposed method allows to synthesize in high yield the proposed compound, which can be used for the synthesis of compounds with fungicidal action.

Claims (2)

Claim 1. A method of obtaining a 3-cyan-4-methyl5-chloro-6-hydroxypyridone-2 of the formula characterized in that 3 cyan-4-methyl-6-hydroxypyridone-2 is reacted with chlorine or chloride sulfuryl followed by zinc reduction of the resulting 1-H -3-cyan-4-methyl-5,5-dichloropyridine- 2,6-dione in alcohol or in a mixture of water-acetone or dioxane with a volume ratio of 1: 2. I 2. The method of pop. 1, characterized in that the interaction with chlorine is carried out at (-10) -80 ° C.