6-Nitro-1H-pyrrolo[2,3-b]pyridine

Synthesis

7-azaindole was added into 10mL dichloromethane, and 4.2mL glacial acetic acid was added slowly dropwise at 0C, stirring for 20min. Then liquid bromine was dissolved in 20mL dichloromethane, and then added into the reaction system dropwise, and the reaction was carried out at 0C for 2h. Thin-layer chromatography tracked and detected the progress of the reaction until the reaction was stopped when no reactant was seen, and TLC detected the product (methanol unfolded reagent), Rf=0.57. After the reaction was completed, saturated aqueous sodium sulfite solution was added to the reaction system until the starch KI paper did not turn blue. Concentrate dichloromethane, add 20 mL of water, at 0 , add NaOH adjusted to pH>13, the reaction mixture solvent spin dry, dissolved in dichloromethane, purified water washed 2 times, the organic phase was dried with anhydrous sodium sulfate, the mixture do silica gel column chromatography separation, the product was vacuum-dried to obtain 1H-pyrrolo[2,3-B]pyridine-6-bromide.

1H-pyrrolo[2,3-B]pyridine-6-bromide and liquid ammonia were added to a four-port round-bottomed flask equipped with magnetic stirring, a thermometer and a reflux condenser tube separator in a certain proportion, and then petroleum ether with a boiling range of 60~90 was added, and the reaction was carried out under nitrogen protection. Thin-layer chromatography tracked the progress of the reaction until the reaction was stopped when no reactants were seen, and the mixture was moved to a pumping flask and subjected to decompression distillation at 40~70C to remove the low-boiling-point amine and solvent to obtain 1H-pyrrolo[2,3-B]pyridin-6-amine.