54-12-6Relevant articles and documents
Dynamic Kinetic Resolution for Asymmetric Synthesis of L-Noncanonical Amino Acids from D-Ser Using Tryptophan Synthase and Alanine Racemase
Yu, Jinhai,Li, Jing,Gao, Xia,Zeng, Shuiyun,Zhang, Hongjuan,Liu, Junzhong,Jiao, Qingcai
, p. 6618 - 6625 (2019/11/03)
L-Ser is often used to synthesize some significant l-noncanonical α-amino acids(l-ncAAs), which are the prevalent intermediates and precursors for functional synthetic compounds. In this study, threonine aldolase from Escherichia coli k-12 MG1655 has been used to synthesize l-Ser. In contrast to the maximum catalytic capacity (20 g/L) for l-threonine aldolase(LTA), d-Ser was synthesized with high yield (240 g/L) from cheap Gly and paraformaldehyde using d-threonine aldolase (DTA) from Arthrobacter sp ATCC. In order to fully utilize d-Ser and expand the resource of l-Ser, a dynamic kinetic resolution system was constructed to convert d/dl-Ser to l-Ser through combining alanine racemase (Alr) from Bacillus subtilis with l-tryptophan synthase (TrpS) from Escherichia coli k-12 MG1655, and l-ncAAs including l-Trp and l-Cys derivatives were synthesized with excellent enantioselectivity and in high yields. The results indicated l-ncAAs could be efficiently synthesized from d-Ser using this original and green dynamic kinetic resolution system, and the reliable l-Ser resource has been established from simple and achiral substrates.
Feed additive method for preparing DL-tryptophan
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Paragraph 0027; 0037; 0038, (2016/10/07)
The invention provides a method for preparing a feed additive DL-tryptophan. The method comprises the following steps of: 1) preparing indole-3-formaldehyde; 2) preparing aceturic acid; 3) preparing 3-indolyl-2-acetamino acrylic acid; 4) preparing N-acetyltryptophan; 5) preparing the DL-tryptophan. The method for preparing the feed additive DL-tryptophan is easy in acquisition of raw materials, low in raw material cost, high in reaction efficiency, and simple in process; the method can be carried out at the normal temperature and under the normal pressure without environmental pollution.
Two-photon sensitive protecting groups operating via intramolecular electron transfer: Uncaging of GABA and tryptophan
Korzycka, Karolina A.,Bennett, Philip M.,Cueto-Diaz, Eduardo Jose,Wicks, Geoffrey,Drobizhev, Mikhail,Blanchard-Desce, Mireille,Rebane, Aleksander,Anderson, Harry L.
, p. 2419 - 2426 (2015/03/30)
Improved photo-labile protecting groups, with high sensitivity to two-photon excitation, are needed for the controlled release of drugs, as tools in neuroscience and physiology. Here we present a new modular approach to the design of caging groups based on photoinduced electron transfer from an electron-rich two-photon dye to an electron acceptor, followed by scission of an ester to release a carboxylic acid. Three different electron acceptors were tested: nitrobenzyl, phenacyl and pyridinium. The nitrobenzyl system was ineffective, giving only photochemical decomposition and no release of the carboxylic acid. The phenacyl system also performed poorly, liberating the carboxylic acid in 20% chemical yield and 0.2% photochemical yield. The pyridinium system was most successful, and was tested for the release of two carboxylic acids: γ-amino butyric acid (GABA) and tryptophan. The caged GABA undergoes photochemical cleavage with a chemical yield of >95% and a photochemical yield of 1%; it exhibits a two-photon absorption cross section of 1100 GM at 700 nm, corresponding to a two-photon uncaging cross section of 10 ± 3 GM. This journal is
