The use and synthesis method of DL-mandelic acid
Uses of Ambergris
14 5 月, 2021About Talc
31 7 月, 2021The use and synthesis method of DL-mandelic acid
DL-mandelic acid is also called mandelic acid, or α-hydroxyphenylacetic acid. Appearance: White crystalline powder, melting point range of 118.0 ~ 121.0°C. DL-mandelic acid is toxic and harmful in contact with skin and if swallowed. Because of its strong antibacterial effect, it can be directly used orally to treat urinary system infections. DL-mandelic acid has a chiral molecule and is an important chiral drug intermediate and fine chemical product. It can not only be used to synthesize vasodilator cyclic mandelate, urinary tract infection anti-inflammatory drug DL-mandelic acid urotropine and antispasmodic DL-Mandelic acid benzyl ester and other drugs, but also have the dual effect of killing sperm and killing trichomoniasis. At present, the demand for DL-mandelic acid in the international market is increasing at an average annual rate of about 10%. DL-mandelic acid and its derivatives have a wide range of applications in organic synthesis. For example, in medicine, it is an important intermediate for the urinary tract fungicide-urotropine mandelic acid, and the peripheral vasodilator-cyclomandelate; in the dye industry, it is also an excellent heterocyclic disperse dye-benzene. An important intermediate of difuranone.
The use of DL-mandelic acid
DL-mandelic acid is used in organic synthesis and pharmaceutical industry. In medicine, it is methyl benzoyl formate, cefoxizole, urotropine mandelic acid, a urinary tract fungicide, and cyclomandelic acid, a peripheral vasodilator, as well as eye drops. It is an important intermediate of Benzazole, Pemoline and Tropine antispasmodics. In addition, it is clinically used as a urethral antiseptic. Preservatives, chemical reagents, also used in organic synthesis, dyes, pesticide raw materials and intermediates, etc.
DL-mandelic acid is used in organic synthesis and pharmaceutical industry. In medicine, it is methyl benzoyl formate, cefoxizole, urotropine mandelic acid, a urinary tract fungicide, and cyclomandelic acid, a peripheral vasodilator, as well as eye drops. It is an important intermediate of Benzazole, Pemoline and Tropine antispasmodics. In addition, it is clinically used as a urethral antiseptic. Preservatives, chemical reagents, also used in organic synthesis, dyes, pesticide raw materials and intermediates, etc.
Resolve resolution
There are three common synthetic methods as follows:
Method one:
There are three common synthetic methods as follows:
Method one:
Mix 15 g of freshly distilled benzaldehyde and 50 ral saturated sodium bisulfite solution, stir with a glass rod, the adduct will precipitate out, stir for 15 minutes, filter with suction, wash the precipitate with a small amount of cold water, add 12 under stirring Grams of potassium cyanide, 25ml of water, the crystals disappeared, and the nitrile alcohol oily matter precipitated out, separated with a separatory funnel. The water layer is extracted once with 15ml of benzene, the benzene is evaporated, the oily substances are combined in an evaporating dish, and 4 times the amount of concentrated hydrochloric acid is added. The water bath is evaporated and concentrated until a large number of crystals appear on the liquid surface. Place it in a cold place overnight, and filter the crystals. ; The filtrate was extracted with ether, and the ether was evaporated to obtain crystals. Combine the crystals, dry for 24 hours, wash the crystals with a small amount of cold benzene, and then extract with hot benzene. The extracted benzene solution is cooled in an ice bath to precipitate crystals, filtered out, and dried. The collection rate is 50-60%. It is also possible to hydrolyze the nitrile alcohol with concentrated hydrochloric acid for 12 hours, then evaporate and concentrate it on a water bath for 5-6 hours, and filter the crystals. The filtrate was evaporated to dryness, and the solids were combined and extracted with hot benzene.
Method 2：
Method 2：
After mixing 0.1 mol of benzaldehyde and 0.005 mol of triethylbenzyl ammonium chloride, add 16 ml of chloroform, heat in a water bath, and slowly add 25 ml of 50% sodium hydroxide aqueous solution (1 to 2 drops per minute, The temperature of the water bath is maintained at 56±2°C for about 2 hours). After the addition, continue stirring at this temperature for 1 hour. After the reaction solution is cooled to room temperature, it is diluted with water. The aqueous solution is extracted twice with ether, and the water layer is separated with 50% sulfuric acid. Acidify and extract with ether. After the extract is dried with anhydrous sodium sulfate, the ether is distilled off, and the remaining oil is cooled and solidified, and then recrystallized with toluene to obtain.
1. Preparation of dichloroacetophenone
Put 384 grams (3.2m01) of acetophenone and 400 ml of glacial acetic acid in a 1-liter three-necked flask, and pour chlorine into the reaction solution at a rate of 200 grams per hour, and use an ice-water bath to control the temperature at 55-57. C. After about 3 hours of chlorine venting, the reaction liquid absorbs chlorine and reaches saturation, and a large amount of yellow-green gas escapes the liquid surface to fill the reaction flask. At this time, the temperature of the reaction liquid drops, and then slowly vent chlorine gas for 10 minutes. In a washing bottle with 1 liter of water, dichloroacetophenone sinks to the bottom of the bottle as a pale yellow oil. The upper layer of acetic acid liquid was decanted, and then washed twice with 500 ml of water, the oily substance, the oily dichloroacetophenone was separated, and the yield was over 90%.
2. Preparation of DL-mandelic acid
In a 1 liter reaction flask, put 96 grams of sodium hydroxide, add 600ral of water to dissolve. Under rapid stirring, slowly add 120 grams of dichloroacetophenone, while controlling the reaction temperature at 60-65 with a water bath. C is added in about 2 hours. After the addition is complete, continue to stir for 1.5 hours. Then add 100ml of concentrated hydrochloric acid to the reaction solution for acidification, then place it in the refrigerator overnight, filter out the crystals, and evaporate the filtrate under reduced pressure to dryness. Dry the residue and crystallize 3 to 4 times, distill the ether to recover the crude product, and add the same amount of water to heat the crude product to dissolve it. Decolorize, filter, place the filtrate in the refrigerator overnight to crystallize, filter the crystals, dehydrate with benzene, 60. C drying, the yield is 62-65%.
Put 384 grams (3.2m01) of acetophenone and 400 ml of glacial acetic acid in a 1-liter three-necked flask, and pour chlorine into the reaction solution at a rate of 200 grams per hour, and use an ice-water bath to control the temperature at 55-57. C. After about 3 hours of chlorine venting, the reaction liquid absorbs chlorine and reaches saturation, and a large amount of yellow-green gas escapes the liquid surface to fill the reaction flask. At this time, the temperature of the reaction liquid drops, and then slowly vent chlorine gas for 10 minutes. In a washing bottle with 1 liter of water, dichloroacetophenone sinks to the bottom of the bottle as a pale yellow oil. The upper layer of acetic acid liquid was decanted, and then washed twice with 500 ml of water, the oily substance, the oily dichloroacetophenone was separated, and the yield was over 90%.
2. Preparation of DL-mandelic acid
In a 1 liter reaction flask, put 96 grams of sodium hydroxide, add 600ral of water to dissolve. Under rapid stirring, slowly add 120 grams of dichloroacetophenone, while controlling the reaction temperature at 60-65 with a water bath. C is added in about 2 hours. After the addition is complete, continue to stir for 1.5 hours. Then add 100ml of concentrated hydrochloric acid to the reaction solution for acidification, then place it in the refrigerator overnight, filter out the crystals, and evaporate the filtrate under reduced pressure to dryness. Dry the residue and crystallize 3 to 4 times, distill the ether to recover the crude product, and add the same amount of water to heat the crude product to dissolve it. Decolorize, filter, place the filtrate in the refrigerator overnight to crystallize, filter the crystals, dehydrate with benzene, 60. C drying, the yield is 62-65%.