Dimethylamine → 6-chloro-L-tryptophan

Participants

Reaction Conditions

Reaction Steps

Under inert atmosphere and rapid stirring 52 mg of NaOH are pulverized into anhydrous xylene (20 ml), heating the suspension at approximately 90° C. 550 mg of 6-chlorogramine (prepared as described in example 1) and 460 mg of ethyl-acetamido-acetate are then added. The mixture is refluxed for approximately 7 hours and the development of dimethylamine, extremely vigorous at the start of the heating, practically ceases after about 6 hours of heating. The reaction mixture is cooled for 12 hours at 5° C. and then filtered to recover the abundant precipitate. This crude solid is treated with a hot solution of benzene/absolute ethanol, and the insoluble material is hot-filtered. The solution is left to rest at 5° C. for 12 hours. Crystals slowly separate, which are filtered and dried. 750 mg of ethyl-α-acetamido-α-cyano-β-(6-chloro-indole-3-yl)-propioanate are recovered, with a yield of 84%. 600 mg of this compound are added to 15 ml of water, containing 40 mg of NaOH and the mixture is boiled for 24 hours. During this time the solid material dissolves and ammonia is developed. After the reflux time, the reaction mixture is cooled at room temperature and neutralized with acetic acid at 50%. It is filtered, recovering and washing with cold water the solid which has formed. After drying 410 mg of 6-chloro-DL-tryptophan are recovered, with a yield of 95%.

Provenance & Evidence