Method for synthesizing tolfenpyrad

Abstract

The invention provides a method for synthesizing tolfenpyrad, relates to a preparation method of the tolfenpyrad, and the method is used for solving the problems such as tedious process and poor product purity of an existing tolfenpyrad synthesis method. The method comprises the following steps of: 1, synthesizing ethyl propionyl pyruvate; 2, synthesizing ethyl 3-ethyl-5-pyrazolecarboxylate; 3, synthesizing ethyl 1-methyl-3-ethyl-5-pyrazolecarboxylate; 4, synthesizing ethyl 1-methyl-3-ethyl-4-chloro-5-pyrazolecarboxylate; 5, synthesizing 4-(4-methyl phenoxy) cyanophenyl; 6, synthesizing 4-(4-methyl phenoxy) benzylamine; and 7, synthesizing the tolfenpyrad. Since sodium ethoxide is replaced by sodium hydroxide, the method provided by the invention has the characteristics of short reaction time, no generation of isomer and high purity of the product; and the obtained product has high purity and does not need re-crystallization.

Description

technical field

[0001] The invention relates to a preparation method of tofenpyrad. Background technique

[0002] At present, it is reported in the literature that the method for synthesizing the insecticide and fungicide tonpyradram is mainly to use butanone and diethyl oxalate as raw materials, through condensation and cyclization with hydrazine hydrate, to obtain ethyl 3-ethyl-5-pyrazolecarboxylate , and then through methylation, chlorination, hydrolysis, acidification to obtain the intermediate 1-methyl-3-ethyl-4-chloro-5-pyrazole carboxylic acid, and then with thionyl chloride, or solid light (also reported for Oxalyl chloride) reacts to generate active acyl chloride, and then generates the final product tonamirad with compound 4-(4-methylphenoxy)benzylamine. The first step condensation part of this method uses toluene as a solvent and sodium ethoxide as a base for the reaction. There is a common problem that isomers are produced, which are close to the boiling point o...

Examples

specific Embodiment approach 1

[0034] Specific embodiment one: the method for synthesizing tofenpyrad according to the present embodiment is carried out according to the following steps:

[0035] 1. Synthesis of ethyl propionyl acetonate:

[0036] Mix 160g of toluene with 22g of NaH, then add 116g of diethyl oxalate butanone solution dropwise for 10 minutes while stirring at -5°C to 5°C. Ethyl ester and 36g butanone, then add 300mL water, add dropwise concentrated hydrochloric acid to adjust the pH value to 5 (add 48.5g concentrated hydrochloric acid in total), let stand, separate the water layer, then use 50mL toluene to extract the separated water layer once, Combine the organic phases, wash the combined organic phases once with 100 mL of saturated brine, and collect the fractions under the conditions of a pressure of 358 Pa and a temperature of 121 to 123° C. to obtain ethyl propionyl acetonate;

[0037] 2. Synthesis of ethyl 3-ethyl-5-pyrazolecarboxylate:

[0038] Add 100 g of dichloroethane to ethyl ...

specific Embodiment approach 2

[0049] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that in step 1, 116 g of diethyl oxalate in butanone solution was added dropwise for 10 minutes under the condition of -3°C to 3°C while stirring. Others are the same as in the first embodiment.

specific Embodiment approach 3

[0050] Embodiment 3: The difference between this embodiment and Embodiment 1 is that in step 1, 116 g of diethyl oxalate in butanone solution was added dropwise for 10 minutes while stirring at 0°C. Others are the same as in the first embodiment.

technical field

[0001] The invention relates to a preparation method of tofenpyrad. Background technique

[0002] At present, it is reported in the literature that the method for synthesizing the insecticide and fungicide tonpyradram is mainly to use butanone and diethyl oxalate as raw materials, through condensation and cyclization with hydrazine hydrate, to obtain ethyl 3-ethyl-5-pyrazolecarboxylate , and then through methylation, chlorination, hydrolysis, acidification to obtain the intermediate 1-methyl-3-ethyl-4-chloro-5-pyrazole carboxylic acid, and then with thionyl chloride, or solid light (also reported for Oxalyl chloride) reacts to generate active acyl chloride, and then generates the final product tonamirad with compound 4-(4-methylphenoxy)benzylamine. The first step condensation part of this method uses toluene as a solvent and sodium ethoxide as a base for the reaction. There is a common problem that isomers are produced, which are close to the boiling point o...

Examples

specific Embodiment approach 1

[0034] Specific embodiment one: the method for synthesizing tofenpyrad according to the present embodiment is carried out according to the following steps:

[0035] 1. Synthesis of ethyl propionyl acetonate:

[0036] Mix 160g of toluene with 22g of NaH, then add 116g of diethyl oxalate butanone solution dropwise for 10 minutes while stirring at -5°C to 5°C. Ethyl ester and 36g butanone, then add 300mL water, add dropwise concentrated hydrochloric acid to adjust the pH value to 5 (add 48.5g concentrated hydrochloric acid in total), let stand, separate the water layer, then use 50mL toluene to extract the separated water layer once, Combine the organic phases, wash the combined organic phases once with 100 mL of saturated brine, and collect the fractions under the conditions of a pressure of 358 Pa and a temperature of 121 to 123° C. to obtain ethyl propionyl acetonate;

[0037] 2. Synthesis of ethyl 3-ethyl-5-pyrazolecarboxylate:

[0038] Add 100 g of dichloroethane to ethyl ...

specific Embodiment approach 2

[0049] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that in step 1, 116 g of diethyl oxalate in butanone solution was added dropwise for 10 minutes under the condition of -3°C to 3°C while stirring. Others are the same as in the first embodiment.

specific Embodiment approach 3

[0050] Embodiment 3: The difference between this embodiment and Embodiment 1 is that in step 1, 116 g of diethyl oxalate in butanone solution was added dropwise for 10 minutes while stirring at 0°C. Others are the same as in the first embodiment.

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