Method for synthesizing tolfenpyrad
A technology of pyrenpyran and ethyl pyrazole carboxylate, which is applied in the field of preparation of tonenpyrad, can solve the problems of low product purity and lengthy methods, and achieve the effects of short reaction time and high product purity
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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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