Method 1: Take 5-bromo-4-chloro-3-indolyl-2,3,4,6-tetra-O-acetyl--D-glucopyranoside dissolved in 15mL of methanol and cooled to 0 in an ice bath; then add 3mL (0.5 mol/L) of sodium methanol methanol solution dropwise and stirred for 5h at this temperature; at the end of the reaction, the reaction solution was poured into pre-treated cationic exchange resin (cationic). After the reaction, the reaction solution was poured into the pre-treated cation exchange resin (pretreatment method of the resin: firstly, rinse the resin with water; then soak it in 5% hydrochloric acid for about 4h, and wash it to neutral; then soak it in 5% sodium hydroxide solution for about 4h, and wash it to neutral; finally, soak it in 5% hydrochloric acid for 4h, and wash it to neutral), and then it was slowly stirred for 5-10min, and then filtered, and then rinsed by methanol, and then the filtrate was evaporated and removed the solvent, and it was obtained as 0.49g of white solid 5-bromo-4-chloro-3-beta-indolyl-beta-indoline-3-beta-indole. -indolyl-beta-D-glucopyranoside, yield 81.6%, melting point 86.5 .
Method 2: 40 mg of compound 5 was dissolved in 5 mL of methanol, cooled to 0 C in an ice bath, then 5 mL (0.2 mol/L) of methanol solution of sodium methanol was added dropwise and stirred for 3 h at this temperature; at the end of the reaction, the reaction solution was poured into pre-treated cation-exchange resin (pre-treatment method as in section 1.2.1) and stirred slowly for 5~10 min; filtered, rinsed with methanol, the filtrate was evaporated to remove the solvent to obtain 10mg of white solid, i.e., 5-bromo-4-chloro-3-indolyl-beta-D-glucopyranoside, with a yield of 40.3% and a melting point of 82.1C. The reaction was completed by pouring the reaction solution into the pre-treated cation exchange resin (pretreatment method as in section 1.2.1).
