With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.108-55-4,Dihydro-2H-pyran-2,6(3H)-dione,as a common compound, the synthetic route is as follows.
Into a 3L three-necked RB flask was charged ethylene dichloride [(500ML),] aluminum chloride [(250GR)] and fluorobenzene [(45GR)] under nitrogen atmosphere. The reaction mixture was cooled to [10C] and a solution of glutaric anhydride [(LOOGR),] fluorobenzene (45gr) and ethylene dichloride [(500ML)] was added slowly over a period of 3hrs between [10-15C.] After maintaining for one hour at [15-18C] the reaction mixture was slowly poured onto a mixture of crushed ice (700gr) and conc. HCI [(300ML)] below [10C.] The reaction mass temperature was raised to reach [25C] and distilled off ethylene dichloride from the reaction mixture below [100C.] After cooling the reaction mixture to [20C,] crude solid was filtered off and washed with [500ML] of water. The wet cake-thus obtained was suspended in 300ml of ethylene dichloride and filtered. The solid compound was dissolved in [600ML] of 4% sodium hydroxide, treated with [15GR] of activated charcoal and filtered. The filtrate was acidified to pH 1. [5-2.] 0 with conc. [HCI] and the precipitated acid was filtered. After washing the wet cake with [500ML] of water, it was dried at [60-70C] to get 130gr of white solid, rn. p. [140-142C.] This solid was dissolved in [500ML] of acetone. The acetone solution was slowly cooled to [15-20C] and the solid filtered, washed with chilled acetone [(50ML)] and dried at [50-70C] to get 120gr of white crystalline solid, m. p. [143C.] Purity by [HPLC] is 99.65%. Desfluoro impurity is less than 0. [05%.]
108-55-4, As the paragraph descriping shows that 108-55-4 is playing an increasingly important role.
Reference£º
Patent; Natco Pharma Limited; Venkaian Chowdary Nannapaneni; WO2003/104180; (2003); A1;,
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