Methane → 6-[3-(Trifluoromethyl)phenyl]pyridazin-3-ol

참여 물질

반응 단계

A 112 g. portion of p-toluenesulfonic acid is dissolved in 500 ml. of tetrahydrofuran with stirring. Then 106 g. of morpholine is added portionwise with stirring. A 95.63 g. portion of m-trifluoromethylbenzaldehyde is added and the reaction mixture is stirred at reflux for 2 hours. The reaction mixture is cooled and a solution of 42.2 g. of potassium cyanide in 75 ml. of water is added. The mixture is then allowed to stir at reflux overnight. The reaction mixture is concentrated free of solvent and the concentrate is partitioned between water and chloroform. The organic layer is washed with saturated sodium bisulfite, dried over magnesium sulfate, treated with activated charcoal and filtered. The filtrate is concentrated in vacuo to afford α-(α,α,α-trifluoro-m-tolyl)-4-morpholineacetonitrile as a dark yellow oil. A 67.0 g. portion of the oil above is dissolved in two liters of tetrahydrofuran with stirring at room temperature. Stirring is continued while eight 10 ml. portions of ethyl acrylate and nine 5 ml. portions of a 30% solution of potassium hydroxide in ethyl alcohol are added to the reaction mixture over a 5 hour period. This reaction is slightly exothermic. The reaction mixture is allowed to stir at room temperature overnight. The mixture is treated with activated charcoal and filtered. The filtrate is concentrated free of solvent then is stripped several times with toluene. The concentrate is stirred with diethyl ether and filtered to remove insolubles. The filtrate is concentrated to a yellow oil then is chromatographed on a 75 cm. × 8 cm. glass column containing silica gel with chloroform as the solvent. The chromatographed material is stripped of chloroform to afford 47.0 g. of γ-cyano-γ-(α,α,α-trifluoro-m-tolyl)-4-morpholinebutyric acid as a yellow oil. The entire amount of the preceding product is combined with two liters of ethyl alcohol and 7.3 ml. of hydrazine hydrate. The mixture is stirred at reflux for 18 hours, then is concentrated free of solvent to afford a yellow oil which is stirred with petroleum ether to yield 14.55 g. of 4,5-dihydro-6-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone as a white solid. The total amount of the product above is dissolved in 225 ml. of glacial acetic acid at ambient temperature, then 3.33 ml. of bromine is dissolved in 25 ml. of acetic acid and 2.5 ml. of this solution is added to the starting material above at room temperature. The reaction mixture is warmed on a steam bath for half an hour while the remaining bromine-acetic acid solution is added dropwise. Following complete discoloration, the reaction mixture is heated on a steam bath for half an hour, and is concentrated free of solvent. The solid concentrate is washed with water, filtered and air dried to afford 6-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone as a cream colored solid.

출처 및 근거