Synthesis
The general procedure for the synthesis of 1-(2-hydroxyethyl)-2,3,3-trimethyl-3H-indole and 2-bromoethanol as raw materials for the synthesis of 1-(2-hydroxyethyl)-2,3,3-trimethyl-3H-indole-1-bromonium was as follows: 3.18 g of 2,3,3-trimethyl-3H-indole and 3.125 g of 2-bromoethanol were dissolved in 30 ml of acetonitrile and transferred to a 100 ml three-necked flask fitted with a condenser. The reaction was slowly heated under nitrogen protection until complete. Upon completion of the reaction, the reaction mixture was slowly cooled to room temperature and the acetonitrile solvent was subsequently removed using a rotary evaporator to give a dark red solid product. To this solid 50 ml of hexane was added and purified by grinding, sonication and filtration. Three grams of the purified product was dissolved in 45 ml of chloroform and recrystallized in a fume hood at 45 °C to give 2.6 g of pink solid product in 87% yield.
References
[1] Synthetic Communications, 2005, vol. 35, # 4, p. 603 - 610
[2] RSC Advances, 2013, vol. 3, # 45, p. 23317 - 23326
[3] Chemical Communications, 2014, vol. 50, # 20, p. 2664 - 2666
[4] Angewandte Chemie - International Edition, 2010, vol. 49, # 43, p. 7968 - 7971
[5] Patent: CN107970448, 2018, A. Location in patent: Paragraph 0021; 0062; 0063
