Dimethylformamide → 1-[3-(Trifluoromethyl)phenyl]-1H-pyrazole-4-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

Into a 500 ml., 2-neck flask, fitted with a condenser and a magnetic stirrer, containing 60.5 ml. (0.78 M.) of absolute dimethylformamide (dried over 3A sieves) is slowly added, while the temperature is maintained at less than 10° C., 36.9 ml. (0.39 M.) of phosphorus oxychloride, after which time the reaction mixture is allowed to stand at room temperature until a bright red color develops (typically, between 30 and 60 minutes). To the resultant reaction mixture is then added 23.2 g. (0.109 M.) of 1-(m-trifluoromethylphenyl)-pyrazole, while the temperature is maintained at between 50° and 70° C. The reaction mixture is then slowly heated to 100° C. and allowed to stand overnight, while the temperature is maintained at 100° C. The reaction mixture is then cooled, quenched in ice water and allowed to stand overnight at room temperature. The resultant precipitated solids are then filtered and washed successively with water and petroleum ether. The solvent is then removed under vacuum to yield 1-(m-trifluoromethylphenyl)pyrazole-4-carboxaldehyde (Yield: 57%). A second crop was also obtained, m.p. 80°-82° C. (Yield: 63%).

Provenance & Evidence