Study On The Synthesis Crafts Of The D-tryptophan

D-tryptophan can be used as feed additives and non-nutritive sweetener, It is also a non-amino acid protein activity which has the advantages of hypoallergenic and resistant, So it is in the feed industry and the pharmaceutical industry has great market and value.The splitting and synthesis of D-tryptophan has been reported early in foreign countries, there is few research in domestic. Therefore, to develope a more economical and efficient route for preparing D-tryptophan is very valuable.Taking indole as a starting material, sequentially synthesize Gramine, DEAM, Diethyl 2-((1H-indol-3-yl) methyl)-2-acetmidomalonate, N-Acetyl-DL-tryptophan, DL-tryptophan, DL-tryptophan is split to obtain the final product namely D-tryptophan at last, and each reaction is optimized in order to obtain better reaction parameters.The optimum conditions for synthesis of gramine:n(indole):n(paraformaldehyde): n(aqueous dimethylamine):n(acetic acid)= 1.0:1.2:1.1:2.5, the reaction at 55℃ for 3h obtain gramine yield up to 98.0%.The optimum conditions for synthesis of DEOM:n(malonate):n(NaON2):n(water): n(acetic acid)= 1.0:1.25:0.3:1.75, the reaction at 40℃ for 6h obtain product yield up to 92.3%. The optimum conditions for synthesis of DEAM:n(DEOM):n(acetic acid): n(acetic anhydride):n(zinc)=1.0:3.0:3.3:2.8, the reaction at 65℃ for 4h obtain DEAM yield up to 86.6%.The optimum conditions for synthesis of Diethyl 2-((1H-indol-3-yl) methyl)-2-acetmidomalonate:n(Gramine):n(DEAM):n(KOH)= 1.0:1.2:0.2, the reaction at 100℃ for 8h obtain product yield up to 93.7%.The optimum conditions for synthesis of N-Acetyl-DL-tryptophan:Diethyl 2-((1H-indol-3-yl) methyl)-2-acetmidomalonate in ethanol with 4%(W/W) sodium methoxide solution, the hydrolysis at 78℃ for 6h obtaine product yield up to 87.5%.The optimum conditions for synthesis of DL-tryptophan:with 10%(W/W) potassium hydroxide solution, the hydrolysis at 100℃ for 8h obtain product yield up to 96.5%.The optimum conditions for spliing DL-tryptophan:n(DL-tryptophan): n(D-camphorsulfonic acid)=1:1, with 70%(V/V) aqueous methanol, the hydrolysis at room temperature for 6h obtain product yield up to 70.4%. optical purity 98.4%. The optimum conditions for hydrolysis D-tryptophan-D-camphorsulfonic acid:with 1 mol/L of triethylamine neutralize D-tryptophan-D-camphor sulfonic acid until PH to 5.9 in water, Stiring for 7h room temperature obtain product yield up to 87.2%. optical purity 97.4%.