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Preparation method, product and application of a class of thiophene-linked 1,3,4-oxadiazole carboxamides

A technology of oxadiazole carboxamide and thiophene carboxyl hydrazide is applied in the field of pesticide synthesis and achieves the effects of novel molecular structure, easy control of reaction conditions and easy availability of raw materials

Inactive Publication Date: 2022-01-04
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] So far, there is no report on the use of thiophene-linked 1,3,4-oxadiazole carboxamides as agricultural fungicides

Method used

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  • Preparation method, product and application of a class of thiophene-linked 1,3,4-oxadiazole carboxamides
  • Preparation method, product and application of a class of thiophene-linked 1,3,4-oxadiazole carboxamides
  • Preparation method, product and application of a class of thiophene-linked 1,3,4-oxadiazole carboxamides

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preparation example Construction

[0043] The schematic diagram of the preparation method of the thiophene-linked 1,3,4-oxadiazole carboxamide compounds of the present invention is shown in figure 1 , including the following steps:

[0044] (1) 2-thiophenecarboxylic acid is esterified to synthesize 2-thiophenecarboxylic acid ester;

[0045] (2) 2-thiophenecarboxylate undergoes hydrazinolysis reaction to obtain 2-thiophenecarboxyhydrazide (1);

[0046] (3) 2-thiophenecarboxyl hydrazide reacts with oxalyl chloride monomethyl ester to generate bisamide intermediate (2);

[0047] (4) The bisamide intermediate (2) is reacted with phosphorus oxychloride to obtain thiophene-1,3,4-oxadiazole formate (3);

[0048] (5) Thiophene-1,3,4-oxadiazole carboxamide was reacted with substituted benzylamine to synthesize thiophene-1,3,4-oxadiazole carboxamide.

Embodiment 1

[0050] Preparation of 1,3,4-oxadiazole methyl ester of thiophene

[0051] Take 2-thiophenecarboxylic acid (6.41g, 50mmol) in a 250mL single-neck flask, add 100mL methanol and catalytic amount of concentrated sulfuric acid (0.5g, 5mmol), add, heat up to reflux temperature, react for 6h, TLC detection, the reaction is completed, cooled After reaching room temperature, saturated sodium bicarbonate solution was added dropwise with stirring until pH=7, ethyl acetate was added for extraction (50 mL×3), the organic layers were combined, washed with saturated brine (100 mL×2), dried over anhydrous sodium sulfate, and extracted. Filtration and desolubilization gave 6 g of oil.

[0052]Dissolve 6 g of the oily substance in 60 mL of ethanol, then add 85% hydrazine hydrate (7.94 g, 211 mmol), and after the addition, reflux for 5 h, TLC detects that the reaction of the raw materials is complete, cool, and rotate to concentrate to remove most of the ethanol. , washed with water (10 mL×3), ...

Embodiment 2

[0056] Preparation of Thiophene-1,3,4-oxadiazolecarboxamide

[0057]

[0058] 4-Chlorobenzylamine (1.2 mmol) was added to 10 mL of DMF solution in which the intermediate thiophene-1,3,4-oxadiazole methyl ester (1.0 mmol) was dissolved, and the temperature was raised to 80 °C and reacted for 2 h. TLC monitored the reaction of the raw materials. , the system was cooled to room temperature, poured into ice water (50 mL), a solid was precipitated under stirring, filtered with suction, and the crude product was recrystallized from petroleum ether / ethanol mixed solvent after drying N-(4-chlorobenzyl)-5-thiophene-2 -yl-[1,3,4]oxadiazole-2-carboxamide (I-1): white solid; yield, 53.3%, m.p.183.6-185.9°C; 1H NMR (600MHz, DMSO-d6) δ9. 91(t,J=6.1Hz,1H),8.03(d,J=4.9Hz,1H),7.93(d,J=3.6Hz,1H),7.40(q,J=8.6Hz,4H),7.33( t, J=4.0Hz, 1H), 4.48 (d, J=6.2Hz, 2H). 13C NMR (150MHz, DMSO-d6) δ161.36, 157.78, 153.04, 137.38, 132.69, 131.62, 131.42, 129.33, 128.95, 128.26 ,123.58,41.89.

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Abstract

The invention discloses a preparation method, product and application of a class of thiophene-linked 1,3,4-oxadiazole carboxamide compounds. 2-thiophenecarboxylic acid synthesizes 2-thiophene hydrazide through methyl esterification and hydrazinolysis reaction, and then reacts with monomethyl oxalyl chloride to obtain a bisamide intermediate, which reacts with phosphorus oxychloride for cyclization The reaction prepares thiophene-linked 1,3,4-oxadiazole carboxylate, and then reacts with substituted benzylamine in one step to synthesize thiophene-linked 1,3,4-oxadiazole carboxamides. The compound has good control effect on rape sclerotinia and tomato early blight under in vitro condition, and can be used to prevent and control agricultural or forestry plant fungal diseases. The preparation method of the compound is simple, the yield is high, and the product has stable properties.

Description

technical field [0001] The invention belongs to the technical field of pesticide synthesis, and particularly relates to a preparation method and product of a class of thiophene-linked 1,3,4-oxadiazole carboxamide compounds and applications thereof. Background technique [0002] The succinate dehydrogenase inhibitor has been developed for nearly 60 years since the commercialization of chlorpyrifosin in 1966, and was the first commercial fungicide containing an amide. The mechanism of action of succinate dehydrogenase fungicides is based on disruption of the mitochondrial tricarboxylic acid cycle and respiratory chain. [0003] The main structures of succinate dehydrogenase inhibitors all contain amide groups. As a kind of commonly used fungicides, the number of varieties accounts for a considerable proportion of fungicides. It develops resistance and, therefore, there is a continuing need to invent new and improved compounds and compositions with fungicidal activity to meet ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D413/04C07D413/14A01N43/824A01P3/00
CPCC07D413/04C07D413/14A01N43/82
Inventor 谷文杨子辉孙月刘青松王石发孙雪宝孙露陈霖霖
Owner NANJING FORESTRY UNIV
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