Method for preparing 4-halo-2-trifluoromethyl acetophenone
A technology of trifluoromethyl acetophenone and methylation, which is applied in the preparation of halogenated hydrocarbons, carboxylic acid nitriles, carbon-based compounds, etc., can solve the problems of high production costs and harsh conditions, and achieve low production costs , mild reaction conditions, beneficial to the effect of industrialization
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preparation example
[0080] This preparation example is used for the preparation of the compound of formula (II)
[0081] X=Cl;
[0082] In a 2L four-necked flask, add 163 g (1 mol, 98%) of o-methyl trifluorotoluene, and then add NCS (1.2 mol, 90 wt %) in batches for 2 hours at 100°C. After the reaction for 4 hours, HPLC The monitoring reaction was completed; 200 mL of DCE and 10wt% sodium hydroxide solution were added to the reacted system to adjust the pH to 7, and the layers were left to stand for stratification, and the organic solvent was removed to obtain the compound shown in formula (II), which was directly used in Next step.
Embodiment 1
[0084] (1A) In a 2L four-necked flask, sequentially add the compound (1mol, 98wt%) of the formula (II) obtained in the preparation example and 600mL of DMF, dropwise add 145.7g (1.2mol, 98wt%) DMF-DMA After 2h dripping, the substitution reaction was carried out at 100 °C. After 6 hours, the raw materials were detected by HPLC, and 5 g of 50wt% sulfuric acid was added. At 60 °C, the hydrolysis reaction was carried out for 2 hours. The raw materials were detected by HPLC. Toluene and 10wt% aqueous sodium hydroxide solution were adjusted to pH 7, left to stand for stratification, the aqueous phase was discarded, and toluene was removed from the organic layer to obtain 204 g of the compound represented by formula (III) with a purity of 98wt% and a yield of 90 %. Wherein, in formula (III), X=Cl.
[0085] (2A) in the four-necked flask of 2L, add the compound 22.8g (0.1mol, 98wt%) shown in formula (III) and the DMF of 100mL successively, then add the hydroxylamine hydrochloride (0.1...
Embodiment 2
[0088] (1B) In a 2L four-necked flask, sequentially add the compound (1mol, 98wt%) of the formula (II) obtained in the preparation example, 600mL of p-chlorotrifluorotoluene, and then add NCS (1.2mol, 90wt%) in batches %), the addition time was 3h, and at 130°C, the halogenation reaction was carried out for 3h, and the reaction was monitored by HPLC; 200mL of DCE and 10wt% sodium hydroxide solution were added to the reaction system to adjust the pH to 7, and left to stand for stratification. , and the organic solvent was removed to obtain 226 g of the compound represented by formula (IV) with a purity of 98% by weight and a yield of 97%. Wherein, in formula (IV), X=Cl and Y=Cl.
[0089] (2B) In a 2L four-necked flask, successively add compound 23g (0.1mol, 98wt%), 100mL of DMF and 5.9g of sodium cyanide to obtain the compound shown in formula (IV), and carry out cyanation reaction at 130° C. for 8h Then, HPLC monitored the end of the reaction; remove the solvent, add 200 mL o...
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