Synthesis
1) Synthesis of N,N-dimethyl-2-chloro-6-nitrostyrene amine: 200g of 2-chloro-6-nitrotoluene, 183g of DMFDMA was added to 150ml of anhydrous DMF solution, heated to 80-120 , the reaction was kept warm for 4 hours, and the end point of the reaction was detected by a GC detector, and the resulting product was cooled down to room temperature and dissolved by adding 1L of toluene solution to the reaction system. After the reaction was complete, the product was cooled to room temperature, and 1L of toluene solution was added to the reaction system to dissolve the product, and after dissolution, the product was washed with saturated brine, after which it was dried with anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain 290g of N,N-dimethyl-2-chloro-6-nitrostyrene vinylamine crude product;
2) Synthesis of 4-chloroindole: 290g of the crude N,N-dimethyl-2-chloro-6-nitrostyrene vinylamine was dissolved in 250 ml of THF and 250 ml of methanol, and then the crude was added to the reaction system and dissolved in 250 ml of THF and 250 ml of methanol. 250 ml of THF and 250 ml of methanol in a mixed solvent, dissolved, under nitrogen protection, 30 C, adding 40 g of Raney nickel, and dropwise addition of 300 ml of hydrazine hydrate with a purity of 80%, the N,N-dimethyl-2-chloro-6-nitrostyrene amine in the - NO2 is reduced to -NH2, the N,N-dimethyl-2-chloro-6-nitrostyrene amine in the - C = C- N- in the C-N bond is broken and the ring-closing reaction is carried out within the reaction system, the synthesis steps are as follows, the resulting product is filtered, the filtrate is concentrated and distilled under reduced pressure to obtain 135 g of 4-chloroindole pure product, and combining steps 1) and 2) to calculate the yield yields can be obtained from the 4-chloroindole obtained in a molar yield of 76.4%.
