Preparation method of 4-chloromethylthiazole

Abstract

The invention relates to the technical field of preparation of pesticide intermediates, and discloses a preparation method of 4-chloromethylthiazole, which comprises the following steps: step 1, solvation: adding 250ml of ethyl acetate into a four-neck flask with the volume of 500ml, cooling to 10-15 DEG C, adding 30g of ammonium dithiocarbamate at one time under the condition, stirring for 30 minutes at a uniform speed, adding 65g of 1, 3-dichloroacetone in multiple batches, stirring for 30 minutes at a constant speed, and cooling to the room temperature; the adding time is 2 hours, the reaction temperature is controlled to be 55-65 DEG C, heat preservation is conducted for 2 hours after adding is completed, cooling is conducted to 10-15 DEG C, and then filtering is conducted to obtain a material A; according to the method, the total yield reaches 95.2%, the reaction condition is mild at 70-75 DEG C, water is adopted as a solvent in the reaction steps, the safety risk is greatly reduced, meanwhile, the cost of adopted raw materials is low, and consumption of preparation resources is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pesticide intermediate preparation, in particular to a preparation method of 4-chloromethylthiazole. BACKGROUND

[0002] 4-chloromethylthiazole is an important organic synthesis intermediate, and its core use is as a key starting material or intermediate for synthesizing a series of thiazole ring-containing pesticides. Thiazole pesticides generally have excellent fungicidal, insecticidal or miticidal activity. Due to the highly active chloromethyl in its structure, 4-chloromethylthiazole is very active and can easily react with nucleophilic reagents (such as amines, alcohols, thiols, etc.) to introduce a thiazole group into a larger target molecule, which is the material basis for pesticide creation and production. Its synthesis process and quality directly affect the cost, yield and quality of the final pesticide product.

[0003] Current synthesis methods of 4-chloromethylthiazole include: 1. producing 4-chloromethylthiazole by chlorinating 4-methylthiazole; 2. synthesizing 4-chloromethylthiazole from 1,3-dichloroacetone and thioformamide; and 3. producing 4-chloromethylthiazole by reacting 1,3-dichloroacetone with thiourea.

[0004] The above methods have the following problems: low overall yield, high raw material cost, generation of a large amount of waste in the production process, generation of a large amount of phosphate in the wastewater, and insufficient product purification technology resulting in a large amount of waste.

[0005] The above information disclosed in the background section is only intended to increase the understanding of the background of the present application, and therefore, it can include information known by those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of 4-chloromethylthiazole to solve the problems raised in the background art.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solution: comprising the following steps:

[0008] Step one, dissolving: add 250ml of ethyl acetate to a 500ml four-necked flask, cool to 10-15°, under this condition, add 30g of dithioammonium carbamate at one time, stir at a constant speed for 30min, add 1,3-dichloroacetone in multiple batches, the addition time is 2 hours, the reaction temperature is controlled at 55-65°, after the addition is completed, keep for 2 hours, cool to 10-15°, then filter to obtain A material;

[0009] Step two, oxidation: after adding 2g catalyst into 500ml four-port flask, add tap water 100ml, add A material by one time, add potassium permanganate 86g by batches, keep temperature at 40-50°, keep temperature for 2 hours after adding, filter out manganese dioxide, wash filter cake with 20ml water, get combined liquid and filtrate;

[0010] Step three, neutralization: add 2g activated carbon into combined liquid from second step, mix for 20 minutes, decolorize and filter, neutralize filtrate with 30% concentration sodium hydroxide, PH=7.5-8.5, separate layers, take upper layer solution, get 4-chloromethylthiazole.

[0011] Preferably, A material in step one is 2-sulfenyl-4-chloromethylthiazole hydrochloride, get dry weight 80g, use for step two.

[0012] Based on the above, the present application includes the following beneficial technical effects:

[0013] Through the method, total yield reaches 95.2%, reaction condition is mild 70-75°, solvent in reaction step is water, greatly reduces safety risk, meanwhile, raw material cost is lower, reduces preparation resource consumption. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0015] The present application provides a technical solution: comprising the following steps:

[0016] Step one, solution: add 250ml ethyl acetate into 500ml four-port flask, cool to 10-15°, under this condition, add dithioammonium carbamate 30g by one time, stir at constant speed for 30min, add 1,3-dichloroacetone 65g by batches, add for 2 hours, control reaction temperature at 55-65°, keep temperature for 2 hours after adding, cool to 10-15°, then filter to get 2-sulfenyl-4-chloromethylthiazole hydrochloride, yield is 96.8%;

[0017] The formula is:

[0018]

[0019] Step two, oxidation: 2g catalyst was added into a 500ml four-necked flask, then 100ml tap water was added, 2-thio-4-chloromethylthiazole hydrochloride was added in batches, 86g potassium permanganate was added in batches, the temperature was kept at 40-50°, and after the addition was completed, the temperature was kept for 2 hours, finally manganese dioxide was filtered out, the filter cake was washed with 20ml water, and the combined liquid and filtrate were obtained;

[0020] The formula is:

[0021]

[0022] Step three, neutralization: the combined liquid obtained in the second step was added with 2g activated carbon, mixed for 20 minutes to decolorize and filter, the filtrate was neutralized with 30% concentration sodium hydroxide, PH=7.5-8.5, layered, and the upper layer solution was obtained, 4-chloromethylthiazole 65.61g was obtained, with a yield of 96.1%.

[0023] The formula is:

[0024] C4H7CLN2·HCL+NaOH→CLCH2CNS+NaCL+H2O

[0025] It should be noted that the relational terms such as first and second and the like are used herein solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0026] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for the preparation of 4-chloromethylthiazole, characterized in that, The method comprises the following steps: Step one, solvate: add 250ml of ethyl acetate into a 500ml four-necked flask, cool to 10-15°, under this condition, add 30g of dithioammonium formate at one time, stir at a constant speed for 30min, add 1,3-dichloroacetone in batches, the adding time is 2 hours, the reaction temperature is controlled at 55-65°, after adding, keep for 2 hours, cool to 10-15°, then filter to obtain A material; Step two, oxidation: add 2g of catalyst into a 500ml four-necked flask, then add tap water 100ml, add A material at one time and stir, add potassium permanganate in batches, the temperature is kept at 40-50°, after adding, keep for 2 hours, finally filter out manganese dioxide, wash the filter cake with 20ml of water, obtain the combined solution and filtrate; Step three, neutralization: add 2g of activated carbon into the combined solution obtained in the second step, mix for 20min, decolorize and filter, neutralize the filtrate with 30% concentration of sodium hydroxide, PH=7.5-8.5, separate the layers, take the upper layer solution, obtain 4-chloromethylthiazole.

2. The process for the preparation of 4-chloromethylthiazole according to claim 1, characterized in that: The A material in step one is 2-sulfido-4-chloromethylthiazole hydrochloride, after obtaining, take 80g of dry weight, which is used in step two.