Studies On The Synthesis Of D-tryptophan

D-tryptophan, one of the non-protein and optically active amino acids, has some special physiological properties, It has great application value by acting as non-calorie sweet agent, toothpaste additive and feed additive in the field of food, commodity and feedstuff, especially as one of the important intermediates of peptide antibiotic and immunosuppressive agent in the field of medicine. Researches on D-tryptophan had been reported in the abroad, but works haven't carried out in our country deeply, so it is very necessary to take full study on it.The starting material is indole.D-tryptophan was prepared through five reactions: the synthesis of gramine, the synthesis of 3-indolyl-methyl-acetamidyl group-diethyl malonic ester, the synthesis of N-acetyl-DL-tryptophan, the resolution of N-acetyl-DL-tryptophan and the synthesis of D-tryptophan. The conditions of these reactions were optimized in the following.Under these process conditions: material quantity is n(indole): n(acetic acid): n(formaldehyde): n(dimethylamine)=1: 0.95: 1: 1.10, reaction temperature is 36 ℃, reaction time is 8h, the yield of gramine can reach the best.Under these process conditions: material quantity is n(gramine) : n(acetamidyl group- diethyl malonic ester)=1:1.1, reaction temperature is 95~100℃, reaction time is 8~9h, the yield of 3-indolyl-methyl-acetamidyl group-diethyl malonic ester can reach the best.Under these process conditions: material quantity is n(3-indolyl-methyl-acetamidyl group-diethyl malonic ester):n(sodium hydroxide)=l :2.5, reaction temperature is 76℃, reaction time is 6h, the concentration of sodium hydroxide solution is 4%, the yield of N-acetyl-DL-tryptophan can reach the best.Under these process conditions: the resolution reagent is A ,material quantity is n(N-acetyl-DL-tryptophan):n(A)=1:1, reaction temperature is 75℃, reaction ti-me is 5h,the yield of N-acetyl-D-tryptophan can reach the best.A mixture of two grams of N-acetyl-D-tryptophan and 20ml 10% sodium hydroxide solution were heated at 60℃ for five hours. We get D-tryptophan.