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A synthesis method and naphthalene formaldehyde technology are applied in the chemical field, can solve the problems of difficult synthesis, high cost, expensive oxidant TEMPO and the like, and achieve the effects of simple reaction conditions and low cost
Inactive Publication Date: 2013-07-24
SHANGHAI RECORD PHARM CO LTD
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[0005] Its disadvantage is that 6-hydroxy-2-naphthylmethanol is rare and expensive. If it is difficult to synthesize by itself, the cost is high, and the oxidant TEMPO used is also very expensive, and
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Embodiment 1
[0031] Step A: In the reaction vessel, add 288g of ethyl naphthol and 1300mL of glacial acetic acid, cool to 10-20°C, and control this temperature, slowly add 704g of bromine dropwise, after the addition is complete, heat up to 50-60°C for reaction After 2 hours, the reaction is complete, add 124g of iron powder, keep warm at 50-60°C for 2 hours, filter while hot, and concentrate the filtrate to dryness to obtain 440g of 6-bromo-2-naphthol, HPLC purity 97.2%, molar yield 95.8 %.
[0032] Step B: In the reaction vessel, put 334.5g of 6-bromo-2-naphthol, add 1500ml of water, add 72g of sodium hydroxide after stirring, stir evenly, control the temperature between 0 and 10°C, slowly add 246g of disulfuric acid disulfide After the addition of methyl ester was completed, the temperature was raised to 20-30°C to react for 4 hours. After the reaction was completed, extract 3 times with ethyl acetate, each time with 750ml of ethyl acetate, combine the ethyl acetate, add 225g of anhydro...
Embodiment 2
[0036] Step A: In the reaction vessel, add 432g of ethyl naphthol and 1950mL of glacial acetic acid, cool to 10-20°C, and control the temperature between 10-20°C, slowly add 960g of bromine dropwise, after the addition is complete, heat up to 50-60°C ℃ for 2 hours, the reaction is complete, add 219g of iron powder, keep warm at 50-60 ℃ for 2 hours, filter while hot, and concentrate the filtrate to dryness to obtain 666g of 6-bromo-2-naphthol, HPLC purity 97.0%, molar yield 96.5% .
[0037] Step B: Put 624.4g of 6-bromo-2-naphthol into the reaction vessel, add 2800ml of water, add 168g of sodium hydroxide after stirring, stir evenly, control the temperature between 0 and 10°C, and slowly add 705.6g of sulfuric acid dropwise After the addition of dimethyl ester is completed, the temperature is raised to 20-30°C for 4 hours. After the reaction is complete, extract with ethyl acetate for 3 times, each time with 1400ml of ethyl acetate, combine the ethyl acetate, add 420g of anhydr...
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Abstract
The invention discloses a synthetic method of 6-hydroxy-2-naphthaldehyde, which comprises the following steps: A. beta-naphthol and bromine are reacted for generating 1, 6-dibromo-2-naphthol; then 1, 6-dibromo-2-naphthol and a reducing agent are reacted for obtaining 6-bromine-2-naphthol; B. 6-bromine-2-naphthol and a methyl esterification reagent are reacted for obtaining 6-bromine-2-naphthyl methyl ether; C. 6-bromine-2-naphthyl methyl ether and magnesium are reacted in a Grignard reaction solvent for generating a Grignard reagent; and then the Grignard reagent and N,N-dimethyl formamide are reacted for obtaining 6-methoxy-2-naphthaldehyde; D. 6-methoxy-2-naphthaldehyde and a demethylating reagent lithium chloride are dissolved in a high boiling point aprotic polar solvent for reaction, thereby obtaining a 6-hydroxy-2-naphthaldehyde. Cheap and easily obtained beta-naphthol is used as raw material according to the invention, and after bromination, reduction, methylation, Grignard, demethylating and other reactions, 6-hydroxy-2-naphthaldehyde is obtained; the invention has good advantages of industrial amplification maturation, simple reaction condition and low cost, and the demethylating yield reaches up to 91% and the overall yield reaches up to 62.8%.
Description
technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for synthesizing 6-hydroxyl-2-naphthaldehyde. Background technique [0002] 6-Hydroxy-2-naphthaldehyde is an important pharmaceutical intermediate with extensive market demand. According to existing bibliographical reports, mainly contain following synthetic method: [0003] Method 1: Using 6-hydroxy-2-naphthalene methanol as raw material, it is obtained by oxidation with TEMPO under the catalysis of cuprous chloride, and the reaction formula is as follows: [0004] [0005] Its disadvantage is that 6-hydroxy-2-naphthylmethanol is rare and expensive. If it is difficult to synthesize by itself, the cost is high, and the oxidant TEMPO used is also very expensive, and industrial production is not competitive. [0006] Method 2: use 6-bromo-2-naphthol as raw material, react with butyllithium at minus 78 degrees, and then react with DMF. The reaction formula is...
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