- Reshaping the active pocket of esterase Est816 for resolution of economically important racemates
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Bacterial esterases are potential biocatalysts for the production of optically pure compounds. However, the substrate promiscuity and chiral selectivity of esterases usually have a negative correlation, which limits their commercial value. Herein, an efficient and versatile esterase (Est816) was identified as a promising catalyst for the hydrolysis of a wide range of economically important substrates with low enantioselectivity. We rationally designed several variants with up to 11-fold increased catalytic efficiency towards ethyl 2-arylpropionates, mostly retaining the initial substrate scope and enantioselectivity. These variants provided a dramatic increase in efficiency for biocatalytic applications. Based on the best variant Est816-M1, several variants with higher or inverted enantioselectivity were designed through careful analysis of the structural information and molecular docking. Two stereoselectively complementary mutants, Est816-M3 and Est816-M4, successfully overcame and even reversed the low enantioselectivity, and several 2-arylpropionic acid derivatives with highEvalues were obtained. Our results offer potential industrial biocatalysts for the preparation of structurally diverse chiral carboxylic acids and further lay the foundation for improving the catalytic efficiency and enantioselectivity of esterases.
- Liu, Xiaolong,Zhao, Meng,Fan, Xinjiong,Fu, Yao
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p. 6126 - 6133
(2021/09/28)
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- Nitrogen-Iodine Exchange of Diaryliodonium Salts: Access to Acridine and Carbazole
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A nitrogen-iodine exchange protocol of diaryliodonium salts with sodium azide salt is developed for general construction of significant functional acridines and carbazoles, in which introduction of nitrogen at a late stage was successfully established avoiding heteroatom incompatibility. Inorganic sodium azide served as the sole nitrogen atom source in this transformation. The diversiform functional acridines and carbazoles were comprehensively achieved through annulated diaryliodonium salts, respectively. Notably, Acridine orange (a fluorescent indicator for cell lysosomal dye) and Carprofen (a nonsteroidal anti-inflammatory drug) were efficiently established through this protocol.
- Wang, Ming,Fan, Qiaoling,Jiang, Xuefeng
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supporting information
p. 216 - 219
(2018/01/17)
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- Carbazole compound, and synthesis method and application of compound
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The invention discloses a carbazole compound represented by a formula (2) and a synthesis method of the compound. A high-iodine salt is taken as a reaction raw material, and under the action of an inorganic nitrogen reagent, an additive, a base and a metal catalyst, a reaction is carried out in a solvent under a condition of 80-150 DEG C to obtain various carbazole compounds. According to the method provided by the invention, nitrogen atoms are introduced in a later period, so that the non-compatibility of nitrogen heterocyclic rings to the reaction conditions such as the metal catalyst and the like in an early reaction period is avoided. In addition, two aryl groups in the high-iodine salt are fully utilized, so that the atomic economic efficiency of the method provided by the present invention is fully exhibited. The carbazole compound prepared by the method provided by the invention can be further applied to the synthesis of non-steroidal anti-inflammatory drug carprofen.
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Paragraph 0099-0102
(2018/06/15)
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- Dihydrocarbazole acetic acid and esters thereof
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A process for preparing 6-chloro-α-methylcarbazole-2-acetic acid and esters thereof by the steps of: (a) reacting 6-chloro-1,2,3,4-tetrahydrocarbazole-2-one with a trialkyl-α-methylphosphonoacetate to yield the corresponding 3,4-dihydro-α-methylcarbazole-2-acetic acid ester; and (b) aromatizing the reaction product of step (a), prior to or after saponification, to yield, respectively, 6-chloro-α-methylcarbazole-2-acetic acid or ester, is described. Additionally, there are described 6-chloro-1,2,3,4-tetrahydrocarbazole-2-one useful as an intermediate, and dihydrocarbazoles useful as intermediates and/or as anti-inflammatory and antirheumatic agents.
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