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A technology of tetramethoxytoluene and a synthesis method, which is applied in the field of chemical synthesis technology, can solve the problems of inconvenient operation, low yield, difficult product purification and the like
Inactive Publication Date: 2006-07-12
JIANGSU YABANG PHARMA RES & DEV
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Problems solved by technology
The synthetic preparation route is inconvenient in operation, the yield is not high, and the product is not easy to purify, so it is not suitable for industrial production
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Embodiment 1
[0023] Dissolve 91 grams of 3,4,5-trimethoxytoluene in 300 milliliters of DMF, add 250 grams of phosphorus oxychloride dropwise under cooling in a water bath, and control the temperature in the reactor below 50°C. React at 90°C until the raw materials are completely reacted. After cooling to room temperature, add ice-water mixture to the reaction kettle, neutralize to neutral with sodium hydroxide solution, then cool to room temperature, precipitate crystals, filter and wash with water. Vacuum drying gave 90.5 g of 2,3,4-trimethoxy-6-methylbenzaldehyde with a yield of 86.2%.
Embodiment 2
[0025] Add 500 milliliters of ethanol and 200 grams of m-chloroperoxybenzoic acid to the reaction kettle, dissolve 90.5 grams of 2,3,4-trimethoxy-6-methylbenzaldehyde in ethanol, add dropwise to the reaction kettle, and add dropwise After finishing, continue to react until raw material reaction is complete. Sodium thiosulfate solution was added, the aqueous phase was extracted with ethyl acetate, dried and then concentrated to obtain 81.3 g of 2,3,4-trimethoxy-6-methylphenol with a yield of 95.3%.
Embodiment 3
[0027] 81.3 g of 2,3,4-trimethoxy-6-methylphenol was dissolved in 500 ml of tetrahydrofuran solvent, 35 g of 60% sodium hydride was added, and 150 g of methyl iodide in tetrahydrofuran (200 ml) was added dropwise. After the dropwise addition, the reaction was refluxed until the reaction of the raw materials was complete, 500 ml of ethyl acetate was added, washed with water, dried and concentrated to obtain crude 2,3,4,5-tetramethoxytoluene. Fractions at 113-115° C. / 3 mmHg were collected by vacuum distillation to obtain 79 grams of pure 2,3,4,5-tetramethoxytoluene with a yield of 90.7%.
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Abstract
The invention relates to a method for synthesizing 2, 3, 4, 5-four metonym toluene, which comprises the following steps: using 3, 4, 5-three metonym toluene as starting raw material, obtaining the intermediate 2, 3, 4-three metonym-6-methxyl benzaldehyde after 2-bit formylated, obtaining 2, 3, 4-three metonym-6-methxyl benzene after oxidizing and obtaining 2, 3, 4, 5-four metonym toluene after methylamine. The methylamine reagent is cheesed form methyl iodide, methyl sulfate, methyl carbonate, and azimethane; the base is cheesed form caustic soda, caustic potash, potash and sodium hydride; the reagent is cheesed form alcohol, tetrahydropyran, acetone and propylidene chloride; the oxidant is cheesed form hydrogen diode solution and perbenzoic acid and so on. The formylation is N, N-dimethyl formamide solution with the drop phosphorus trichloride temperature below 50 deg. and the reacting temperature 60 deg.-100 deg.
Description
technical field [0001] The invention relates to a chemical synthesis process, in particular to a synthesis method of a pharmaceutical chemical intermediate 2,3,4,5-tetramethoxytoluene. Background technique [0002] 2,3,4,5-Tetramethoxytoluene is a very important pharmaceutical and chemical intermediate, mainly used in the synthesis of coenzyme Q series products (Q 0～10 ) raw materials. The synthesis method of 2,3,4,5-tetramethoxytoluene reported in the literature includes: taking p-cresol as raw material, after bromine bromination, methoxylation and methylation to obtain 2,3,4, 5-tetramethoxytoluene, or 3,4,5-trimethoxytoluene as raw material, after bromine bromination, methoxylation to obtain 2,3,4,5-tetramethoxytoluene. The synthetic route is shown in the figure below (J.Org.Chem.1987, 52, 3872-3875). The synthetic preparation route is inconvenient to operate, the yield is not high, the product is not easy to purify, and is not suitable for industrial production. [00...
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