Preparation method of N-benzyl-3-indolemethanol_Industrial additives

Background and overview^[2]

N-Benzyl-3-indolecarbinol is an indole-3-carbinol derivative. Indole-3-carbinol is the main anti-cancer active ingredient in cruciferous vegetables. Since Wattenberg et al. first reported in 1978 that indole-3-carbinol can inhibit polycyclic aromatic hydrocarbon-induced tumors in rats, people have confirmed through different animal experimental studies that indole-3-carbinol and its derivatives have an inhibitory effect on tumors induced by chemical substances. It has an inhibitory effect on cancers such as breast cancer, endometrial cancer, thyroid cancer, colon cancer, pancreatic cancer, and liver cancer that occur spontaneously or spontaneously. Since indole-3-carbinol is derived from food, has almost no side effects, and has various anti-cancer activities, it has great development prospects and is expected to become a new generation of food anti-cancer agent and be widely used. As a food additive, indole-3-carbinol has great potential for development. Indole-3-methanol has passed the US FDA certification. At the same time, by using indole-3-carbinol as the core for structural modification and introducing some different substituent groups, it is expected to find chemical anticancer agents with higher efficacy.

Preparation^[1]

13.2g of alkaline catalyst sodium hydride (60%, dispersed in mineral oil) was added into the DMSO solution (1.8L) of 3-aldehyde indole (43.5g) in small amounts and multiple times while stirring at room temperature. After 1 hour, benzyl chloride (37.8g) was added dropwise, and the stirring reaction was continued for 3 hours. Inject 10L of water into the reaction system to terminate the reaction. Extract with 5L methylene chloride three times, then wash the organic phase three times with 10% NaCl solution, dry the organic phase with anhydrous Na₂SO₄, and filter out Na2SO4. Evaporate the methylene chloride in the filtrate under reduced pressure, dissolve the residue in 1L CHCl₃/MeOH (20/1, v/v), and purify the product with silica gel column chromatography. The eluent is CHCl₃/MeOH(20/1, v/v). 1-Benzyl-3-aldehyde-indole can be obtained. The white needle-like solid can also be obtained by recrystallization (Et2O/n-hexane). The molecular formula calculated by ESMS analysis is C16H13NO, [M+H]=236.

Stir the suspension of 1-benzyl-3-aldehyde-indole (0.1mol) in isopropyl alcohol (10L) in an ice bath, and add NaBH₄( 49.1g). After 10 minutes, stirring was continued at room temperature for 1-2 hours until the reaction was complete (endpoint monitored by TLC). The reaction was stopped by adding acetone (1 L). The reaction mixture was concentrated under reduced pressure. Dissolve the residue with ether or chloroform. After washing the organic phase with water (20L) and salt (20L), it was dried over anhydrous sodium sulfate. Removal of the organic solvent gave the crude product. For further purification, the method of recrystallization (Et₂O/n-hexane, 1/1) can also be used to obtain a white needle-like solid. The molecular formula calculated by ESMS analysis is C16H15NO, [M+H]=238.

References

[1][Chinese invention] Preparation method of CN200710069695.9 indole derivatives

[2] Zhou Jiadong, Cao Fei, Li Zhenjiang, An Xiao, Wei Ping. Synthesis of N-substituted indole-3-carbinol [J]. Fine Chemicals, 2007(04):380-384.