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ChemicalBook CAS DataBase List 7,10-Dimethoxy-10-DAB III
183133-94-0

7,10-Dimethoxy-10-DAB III synthesis

14synthesis methods
Solvent is methylene dichloride, and alkali is the two dimethylamino naphthalene of 1,8-, and the mol ratio of 10-deacetylate Bakating III and trimethylammonium oxygen Tetrafluoroboric acid is 1:35; The mol ratio of 10-deacetylate Bakating III and alkali is 1:45;By 10-Dab (10g, 18.4mmol) be dissolved in methylene dichloride (200ml), add 1, the two dimethylamino naphthalene (177.2g of 8-, 828mmol), stirring at room temperature half an hour, add trimethylammonium oxygen Tetrafluoroboric acid (95.2g, 643.4mmol) again, stirring at room temperature 20h, suction filtration reaction solution, filter cake methylene dichloride washes 3 times, collects filtrate, and after concentrated, column chromatography (chloroform: methyl alcohol=100:3) obtains 7,10-dimethoxy-10Dab III 4.6g, yield 43.7%.
32981-86-5 Synthesis
10-Deacetylbaccatin III

32981-86-5
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7,10-Dimethoxy-10-DAB III

183133-94-0
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Yield: 89.6%

Reaction Conditions:

with dmap;caesium bromide;sodium hydride in tetrahydrofuran;N,N-dimethyl-formamide at -30; for 3 h;Temperature;Reagent/catalyst;

Steps:

1.1 (1) Preparation of 7,10 methoxy 10-DAB
Add 100 g of 10-DAB to a dry three-necked flask, dissolve in 50 mL of DMF and 150 mL of tetrahydrofuran, stir magnetically, wait for complete dissolution, add 50 g of cesium bromide, and cool to -30 ° C under ice bath conditions, and add sequentially. 10 g of sodium hydride and 1 g of DMAP were kept under low temperature conditions, 50 mL of dimethyl carbonate was added dropwise, and the reaction was carried out for 3 hours after mixing. After the TLC test showed that the reaction was completed, the reaction solution was added to a solution of 20% by mass aqueous sodium hydrogencarbonate solution in 2000 mL. After 2 hours, the kaba intermediate intermediate 7,10 methoxy 10-DAB crystal was obtained by vacuum distillation; the crystal was washed successively with ethyl acetate for several times, and dried to obtain 105 g of white crystals, and the detected content was 85.3%, and the reaction yield was obtained. It is 89.6%.

References:

Yunnan Han De Biological Co., Ltd.;Ma Huimin;Yang Qingchun;Li Yanlan;Ma Huaihu CN108003119, 2018, A Location in patent:Paragraph 0017; 0021; 0025

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