Abamectin derivatives, and preparation method and application thereof
A technology of abamectin and derivatives, applied in the field of compound preparation, can solve the problem of insufficient contact killing activity of larvae
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Embodiment 1
[0096] Embodiment 1: the preparation of compound I
[0097] Get Abamectin B2 (Hebei Xingbai Co., Ltd., wherein B2a content is >97%, and B2b content is <2%) 40g and tert-butyldimethylsilyl chloride 38.58g in the 1000ml round bottom flask, add 2.94 g4-dimethylaminopyridine and 39.64g imidazole were dissolved in 400ml dry N,N-dimethylformamide, and stirred vigorously at room temperature for 8h. The temperature was lowered to 0°C, and 400ml of water was added to precipitate a solid. After continuing to stir and dissolve, it was extracted three times with 500ml of ether, and the organic phase was separated, and the separated organic phase was extracted with saturated NaCl. Excess ether was distilled off under reduced pressure. A viscous solid was obtained, which was separated and purified by column chromatography, using ethyl acetate:petroleum ether=1:9 as the eluent. 40 g of white solid was obtained, the content was 95.0%, and the yield was 99.04%. It is the compound I of the s...
Embodiment 2
[0099] Embodiment 2: the preparation of compound II
[0100] Take 10 g of compound I with the structure shown in formula I obtained in Example 1, dissolve it in 100 ml of β-trimethylsilyl ethanol, add 3.45 g of tetraisopropyl titanate, and put it in a 250 ml round bottom flask at 120 °C under the protection of inert gas Stir for 10 h, cool down to room temperature, pressure 100 Pa, and distill under reduced pressure at 80°C to remove excess solvent. An orange-red viscous solid was obtained, which was separated and purified by column chromatography, using ethyl acetate:petroleum ether=1:8 as the eluent. 5.2 g of milky white solid was obtained, the content was 92.2%, and the yield was 49.33%. That is, compound II with the structure shown in formula II.
[0101] H NMR spectrum and mass spectrometry analysis results: 1 HNMR (CHCl 3 , 400Hz) δppm: 6.09(d,1H), 5.59-5.79(m,2H), 5.39(m,2H), 5.33(d,2H), 4.77(s,1H), 4.72(d,1H), 4.64 (s,2H),4.52(s,1H),4.45(t,1H),4.24(t,1H),4.22(m,2H...
Embodiment 3
[0102] Embodiment 3: the preparation of compound III
[0103] Get 5g of the compound II of the structure shown in the obtained formula II of Example 2, 19 seco ester is dissolved in 50ml of dry dichloromethane, add 1.89g of pyridine, and 1.80g of Dess Martin oxidant, in a 100ml round bottom flask, at room temperature After reacting for 1 hour under the protection of an inert gas, 1.80 g of Dess Martin oxidant was added. After reacting for 2 hours, add the reaction solution to 100ml 1:1 saturated NaHCO 3 : saturated NaS 2 S 2 o 3 , the organic phase was separated by extraction with dichloromethane and MgSO 4 Dry, filter and distill off excess solvent under reduced pressure. Separation and purification by column chromatography, using ethyl acetate:petroleum ether=1:8 as the eluent, obtained 3.5 g of a light yellow solid with a content of 92.15% and a yield of 70.32%. It is the compound III of the structure shown in formula III.
[0104] H NMR spectrum and mass spectrometr...
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