108-55-4, Dihydro-2H-pyran-2,6(3H)-dione is a Tetrahydropyrans compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated
Into a 3L three-necked RB flask were charged [500ML] of methylene chloride, 250gr of aluminum chloride and 45gr of fluorobenzene (benzene content 300ppm) under nitrogen atmosphere. ‘The reaction mixture was cooled to [10C] and a solution of [LOOGR] of glutaric anhydride, 45gr of fluorobenzene (benzene content 300ppm) and [500ML] of methylene chloride was added slowly over a period of 3hrs between [10-15C.] The reaction mixture was maintained for another one hour at the same temperature. The reaction mixture was slowly poured onto a mixture of crushed ice (700gr) and conc. HCI [(300ML)] below [10C.] The reaction mass temperature was allowed to reach [25C] and methylene chloride distilled off from the reaction mixture below [50C.] After cooling the reaction mixture to [20C,] solids were filtered off and washed with [500ML] of water. The wet cake thus obtained was suspended in [250-300ML] of methylene chloride and filtered. The solid compound was dissolved in [600ML] of 4% sodium hydroxide, treated with [LOGR] of activated charcoal and filtered. The filtrate was acidified with conc. HCI and the precipitated acid was filtered. After washing the wet cake with [500ML] of water, it 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 122gr of white crystalline solid, m. p. [143C.] Purity by [HPLC] is 99.65%. Desfluoro impurity is less than 0.05%. Example 2 Preparation of [4- (4-FLUOROBENZOY) LBUTYRIC ACID] of formula-I using fluorobenzene (benzene content [500PPM)] with methylene chloride as solvent: Into a 3L three-necked RB flask were charged [500MI] of methylene chloride, 250gr of aluminum chloride and 45gr of fluorobenzene (benzene content 500ppm) under nitrogen atmosphere. The reaction mixture was cooled to [10C] and a solution of [LOOGR] of glutaric anhydride, 45gr of fluorobenzene (benzene content [500PPM)] and [500ML] of methylene chloride was added slowly over a period of 3hrs between [10-15C.] The reaction mixture was maintained for another one hour at the same temperature. The reaction mixture was slowly poured onto a mixture of crushed ice (700gr) and conc. [HCL] [(300ML)] below [10C.] The reaction mass temperature was allowed to reach [25C] and methylene chloride distilled off from the reaction mixture below [50C.] After cooling the reaction-mixture to [20OC-1 SOLIDS :] were filtered off and washed with [500ML] of water. The wet cake thus obtained was suspended in [250-300ML OF] methylene chloride and filtered. The solid compound was dissolved in [600ML] of [4%] sodium hydroxide, treated with [10GR] of activated charcoal and filtered. The filtrate pH was adjusted’to 1.0-2. 0 with conc. [HCL] and the precipitated acid of formula-I was filtered. After washing the wet cake with [500ML] of water, it was dissolved in [500ML] of acetone. The acetone solution was slowly cooled to [15-20C,] maintained for 2h, and the solid filtered, washed with chilled acetone [(50ML)] and dried at [50-70C] to get 120gr of white crystalline solid of [FORMULA-1,] m. p. 143-143. [5C.] Purity by [HPLC] is 99. [7%.] Desfluoro impurity is less than 0.05%. Example 3 Preparation of [4- (4-FLUOROBENZOY)] lbutyric acid of formula-I using fluorobenzene (benzene content 700ppm) with methylene chloride as solvent: Tnto a 3L three-necked RB flask were charged 500ml of methylene chloride, 250gr of aluminum chloride and 45gr of fluorobenzene (benzene content [700PPM)] under nitrogen atmosphere. The reaction mixture was cooled to [10C] and a solution of [LOOGR] of glutaric anhydride, 45gr of fluorobenzene (benzene content 700ppm) and [500ML] of methylene chloride was added slowly over a period of 3hrs between [10-15C.] The reaction mixture was maintained for another one hour at the same temperature. The reaction mixture was slowly poured onto a mixture of crushed ice (700gr) [AND CONC. HCI (300ML)] below [10C.] The reaction mass temperature was allowed to reach [25C] and methylene chloride distilled off from the reaction mixture below [50C.] After cooling the reaction mixture to [20C,] solids were filtered off and washed with [500ML] of water. The wet cake thus obtained was suspended in [250-300ML] of methylene chloride and filtered. The solid compound was dissolved in [600ML] of 4% sodium hydroxide, treated with [LOGR] of activated charcoal and filtered. The filtrate pH was adjusted to 1.0-2. 0 with conc. [HCL] and the precipitated acid of formula-I was filtered. After washing the wet cake with [500ML] of water, it was dissolved in 500ml of acetone. The acetone solution was slowly cooled to [15-20C,] maintained for 2h, and the solid filtered, washed with chilled acetone [(50ML)] and dried at [50-70C] to get 123gr of white crystalline solid [OF FORMULA-1,] m. p. [143C.] Purity by [HPLC] is 99.6%. Desfluoro impurity is less than 0.05%.
108-55-4 Dihydro-2H-pyran-2,6(3H)-dione 7940, aTetrahydropyrans compound, is more and more widely used in various.
Reference£º
Patent; Natco Pharma Limited; Venkaian Chowdary Nannapaneni; WO2003/104180; (2003); A1;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics