Method for synthesizing 24-epibrassinolide

A technology of epibrassinolide and lactonization, which is applied in the direction of steroids and organic chemistry, can solve the problems of high toxicity, pollution, and environmental pollution, and achieve mild reaction conditions, short process flow, and low environmental pollution. pollution effect

Active Publication Date: 2020-04-14
JINGBO AGROCHEM TECH CO LTD
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Problems solved by technology

They optimized the synthetic route on the basis of Thompson et al., and reduced the synthetic steps to seven steps, with a total yield of only about 10%. Lower reduction system, while the sulfonylation step uses pyridine as a solvent and methanesulfonyl chloride is highly toxic, and the oxidation step uses a large amount of chromium

Method used

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  • Method for synthesizing 24-epibrassinolide

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (22E,24R)--5α-ergosterol-5,7,22-triene-3-p-toluenesulfonyl ester (compound 2) was prepared by putting ergosterol 39.6g (0.1mol) into the four-necked bottle, triethyl 12.1g (0.12mol) of amine, 300ml of toluene, lower the temperature to 0-5°C, add 21.0g (0.11mol) of p-toluenesulfonyl chloride dropwise, and react at 5°C for 2h. After the reaction, filter with suction and wash the filtrate twice with water. Negative pressure precipitation yielded 52.9 g of sulfonylated ergosterol (compound 2), with a yield of 95.9%.

[0025] Preparation of α-5-cyclo-5α-ergosta-7,22-dien-6-ol (compound 3)

[0026] Drop into potassium bicarbonate 9.1g (0.091mol) in the four-necked flask, 300ml water, and add 1200ml acetone, heat up to reflux, then 50g (0.091mol) compound 2 points are added in the four-necked flask in 2 times, after adding, Reflux reaction for 3h. After the reaction was completed, the acetone was distilled off, and then the reaction solution was lowered to room temperature, ...

Embodiment 2

[0041] (22E,24R)--5α-ergosta-5,7,22-triene-3-p-toluenesulfonyl ester (compound 2)

[0042] Put 39.6g (0.1mol) of ergosterol, 20.73g (0.15mol) of potassium carbonate, and 300ml of toluene into the four-necked bottle, cool down to 5-10°C, add 22.9g (0.12mol) of p-toluenesulfonyl chloride dropwise, 8 The reaction was carried out at ℃ for 2 hours. After the reaction was completed, suction filtration was carried out, the filtrate was washed twice with water, and the solvent was precipitated under negative pressure to obtain 52.8 g of sulfonylated ergosterol, with a yield of 94.7%.

[0043] α-5-cyclo-5α-ergosta-7,22-dien-6-one (compound 4):

[0044] Put 330g (0.076mol) of the compound and 100ml of methanol into the four-neck flask, add 19.83g (0.228mol) of manganese dioxide powder regenerated three times and 120ml of water, inject air with an air pump, and raise the temperature to 60°C for 8 hours. After suction filtration, the filtrate was extracted three times with ethyl acetate,...

Embodiment 3

[0049] (22E,24R)--5α-ergosta-5,7,22-triene-3-p-toluenesulfonyl ester (compound 2)

[0050] Put 39.6g (0.1mol) of ergosterol, 13.8g (0.13mol) of sodium carbonate, and 330ml of toluene into the four-necked bottle, cool down to 10°C, add 24.78g (0.13mol) of p-toluenesulfonyl chloride dropwise, and react at 10°C After 2 hours of reaction, suction filtration was performed, the filtrate was washed twice with water, and precipitation under negative pressure was performed to obtain 53.0 g of sulfonylated ergosterol with a yield of 96.3%.

[0051] α-5-cyclo-5α-ergosta-7,22-dien-6-one (Compound 4)

[0052] Put 30g (0.076mol) of compound 3 and 100ml of methanol into the four-neck flask, add 6.61g (0.076mol) of manganese dioxide regenerated six times and 110ml of water, use an air pump to introduce air, and heat up to 20°C for 14h. After suction filtration, the filtrate was extracted three times with ethyl acetate, dried, and concentrated to obtain 28.3 g of compound 4 with a yield of 93...

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Abstract

The invention belongs to the technical field of organic synthesis. Based on a seven-step synthesis process, p-toluene sulfonyl chloride is used as an acylation reagent; a manganese dioxide/air catalytic system is used in a water and methanol system; and a calcium/HMPA/R1(CH2)nR2 reduction system is used. According to the synthesis method of the 24-epibrassinolide, ergosterol is used as a startingraw material, a seven-step synthesis process is adopted, the method comprises esterification, hydrolysis, oxidation, reduction, rearrangement, dihydroxylation and lactonization; methylbenzene is usedas a solvent in the esterification process, and ergosterol reacts with benzene sulfonyl chloride in the presence of an acid-binding agent; wherein a manganese dioxide/air system is adopted in the oxidation process, methanol is used as a solvent, and oxidation is performed in air; and a calcium/R1(CH2)nR2//HMPA/reduction system is adopted in the reduction process. According to the synthesis method,the total yield is increased by 20 points or above, the product quantitative content is 85% or above, the reaction condition is mild, the technological process is short, the operation is convenient,manganese dioxide can be recycled, low toxicity and low environmental pollution are achieved, and the synthesis method is suitable for industrial production of 24-epibrassinolide.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, relates to the technical field of pesticide compound synthesis, in particular to the synthesis technology of chiral plant growth regulators. Background technique [0002] In the early 1980s, a research institute affiliated to the United States Department of Agriculture extracted a compound with a steroidal skeleton structure from rapeseed pollen, which was named brassinolide (also called brassinolide), 24-epi Brassinolide is the first sterol compound with plant growth regulation effect. In addition to inhibiting the activity of oxidase in plants, it can also increase plant respiration and regulate the balance of endogenous hormones, so that plant tissues can maintain a high Penetration and the ability to maintain young and prolong decline, thereby promoting plant growth and reproduction, and achieving the purpose of increasing production. At present, most of the plant growth regulators...

Claims

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Application Information

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IPC IPC(8): C07J73/00
CPCC07J73/003
Inventor 周芙蓉王中洋宫薇薇王祥传刘志远张道磊
Owner JINGBO AGROCHEM TECH CO LTD
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