Production of Chiral Aromatic Alcohol by Asymmetric Reduction with Vegetable Catalyst

Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceu-ticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral alcohol using vegetables as the biocatalyst. Acetophenone was chosen as the model substrate. The results in-dicate that acetophenone can be reduced to the corresponding chiral alcohols with high enantioselectivity by the chosen vegetables,i.e. apple(Malus pumila),carrot(Daucus carota),cucumber(Cucumis sativus),onion(Allium cepa),potato(Soanum tuberosum),radish(Raphanus sativus),and sweet potato(Ipomoea batatas) . In the reaction,R-1-phenylethanol is produced with apple,sweet potato and potato as the catalyst,while S-1-phenylethanol is the product with the other vegetables as the catalyst. In term of the enantioselectivity and reaction yield,carrot(D. ca-rota) is the best catalyst for this reaction. Furthermore,the reaction characteristics were studied in detail using car-rot(D. carota) as the biocatalyst. The effects of various factors on the reaction were investigated and the optimal reaction conditions were determined. Under the optimal reaction conditions(reaction time 50 h,substrate concen-tration 20 mmol·L-1,reaction temperature 35 °C and pH 7),95% of e.e.(to S-1-phenylethanol) and 85% chemical yield can be obtained. This work extends the biocatalyst for the asymmetric reduction reaction of prochiral aromatic ketones,and provides a novel potential route to produce enantiopure aromatic alcohols.

A Chiral Phosphorous Derivatizing Agent for the Determination of the Enantiomeric Excess of Chiral Alcohols, Amines by ^(31)P NMR

A chiral phosphorous derivatizing agent prepared from PCl3 and (S)-BINOL was described. It is used to determine the enantiomeric excess of chiral alcohols and amines by 31P NMR.

Enantioselective Synthesis of Chiral 1-Ferrocenyl Alcohol via CBS-Reduction

Reduction of prochiral ferrocenyl ketones 2a-e in the presence of 10 mol% of chiral beta -amino alcohols 4a-b provides 1-ferrocenyl alcohols 1a-e in high yields (> 85%) with high optically purity (e.e. up to 96%).

Synthesis of a New Chiral Cyclicβ-Amino Alcohol

A new chiral cyclic β-amino alcohol (R)- 1 -(l '-amino-2'-naphthylethyl)-cyclopentanol2, which had notbeen reported previously, was prepared from (R) - 3 - (2 - naphthy1 )- alanine 3.

The Ability of Edible Mushrooms to Act as Biocatalysts: Preparation of Chiral Alcohols Using Basidiomycete Strains

To examine the potential ability of edible mushrooms to act as biocatalysts, 19 basidiomycete strains were screened. Modified media (PG, O, and PGO medium) for liquid cultivation of these basidiomycete strains were designed and tested. Wet cells (>10 g) of 4 basidiomycete strains (Pleurotus salmoneostramineus H7, P. salmoneostramineus H13, Ganoderma lucidum NBRC31863, Flammulina velutipes NBRC31862) were harvested from PGO medium for 7 days. The stereoselective reduction of α-keto esters using the 4 strains was tested. It was found that each of these strains had a reducing activity toward 6 aliphatic α-keto esters. In the presence of L-alanine as an additive, the reduction of ethyl 2-oxobutanoate and ethyl 2-oxopentanoete by P. salmoneostramineus H7 produced the corresponding alcohol with a high conversion ratio and with excellent enantiomeric excess (>99% e.e. (R)). Furthermore, ethyl pyruvate, ethyl 2-oxobutanoate, and ethyl 2-oxopentanoate were predominantly reduced to the corresponding (R)-hydroxy ester (>99% e.e.) by G. lucidum. Thus, we found that these edible mushrooms have great potential to be used as biocatalysts for the stereoselective reduction of carbonyl compounds.

Synthesis,Characterization and Structure of Chiral Amino Acids and Their Corresponding Amino Alcohols with Camphoric Backbone

Chiral amino acids and their corresponding amino alcohols bearing camphoric backbone were prepared from D-（＋）-camphoric imide and characterized by infrared, elemental analysis, ESI-MS, and NMR measurements. Among them, one intermediate （1S,3R）-3-amino-2,2,3- trimethyl cyclopentane-1-carboxylic acid hydrochloride 3 was structurally elucidated by X-ray diffraction techniques. Versatile intermolecular hydrogen bonding interactions observed in its packing structure result in a two-dimensional framework.

Boosting chiral carboxylic acid hydrogenation by tuning metal-MO_(x)-support interaction in Pt-ReO_(x)/TiO_(2) catalysts

Engineering the surface microenvironment by tuning the binary interactions between a supported metal with a secondary metal oxide(MO_(x))or support has been a common method for improving the catalytic performance of supported metal catalysts.However,few studies have investigated the ternary interactions among the metal,MO_(x),and support.Here,we report for the first time the formation of metal-MO_(x)-support interaction(MMSI)in reducible TiO_(2)-supported PtReO_(x) catalysts,affording 87% yield and 100% ee in the tandem hydrogenation of an aqueous chiral cyclohexane-1,2-dicarboxylic acid into the corresponding diol;the catalytic activity is eight times higher than that obtained with non-reducible support counterparts in the same reaction via traditional batch synthesis with multiple steps and unfriendly reagents.Detailed experimental and computational studies suggest that the TiO_(2) crystalline phase-dependent density of the oxygen vacancies induces different Pt-ReO_(x)-TiO_(2) interactions,which dominate the electron transfer therein and tune the adsorption strength of the carbonyl moiety of the substrate/intermediate,thus promoting the hydrogenation activity and selectivity.In addition,the strong MMSI endows the optimal rutile TiO_(2) supported PtReO_(x) catalyst with an outstanding lifetime of 400 h in a fixed-bed reactor under acidic aqueous conditions and ensures efficient applications in the selective hydrogenation of aliphatic dicarboxylic acids and functional carboxylic acids.This work provides a promising strategy for the development of efficient and stable supported catalysts for the selective hydrogenation of diverse C-O and C=O bonds.

Schiff-base Amino Alcohol-zinc Complex for Enantioselective Addition of Phenylacetylene to Aromatic Ketones

A complete study of the asymmetric addition of phenylacetylene to ketones catalyzed by Schiff-base amino alcohol-Zn complex is reported in this article. The Schiff-base amino alcohols were easily prepared from amino acids in three steps. When the amount of ligand was 1%（molar fraction）, an e.e. value up to 94% was obtained. A series of practical chiral ligands were applied in the enantioselective addition of phenylacetylene to ketones without adding another stronger Lewis acid except zinc.

Chiralcel OD-H手性柱拆分醇类对映体

以Chiralcel OD-H手性商品柱在正相条件下对9种醇类对映异构体进行拆分,考察了流速、流动相中异丙醇含量、柱温等主要因素对手性拆分的影响.试验结果表明:当流动相为正己烷∶异丙醇(90∶10,v/v)、流速为0.5 mL/min、柱温为25℃、检测波长为254 nm时,8种手性醇得到分离,其中7种化合物达到基线分离,且分离度分别为R s1=12.73、R s 3=4.67、R s4=1.75、R s5=11.80、R s6=1.84、R s8=2.22、R s9=12.34,对映体在色谱固定相上的分离过程中主要受吸附焓控制.该方法快速、高效、简便,适用于手性醇类化合物的拆分.

Asymmetric hydrogenation of aromatic ketones using new chiral-bridged diphosphine/diamine-Ru(Ⅱ) complexes

A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new（（Rax）-BuP）/（R,R）-DPEN-Ru（Ⅱ） complex catalyst system.The hydrogenation of 2-methylacetophenone in n-butanol （t-BuOK/Ru =45.6/1,S/C = 500,20 atm.of H2,20℃,48 h） afforded（S）-1-（2＇-methylphenyl）ethanol in 92%ee and〉99% conversion.

Enantiomeric Separation of Amino Alcohols by Ion-pair Chromatography

Enantiomers of four amino alcohols were resolved by ion-pair chromatography with (+)-10-camphorsulphonic acid as chiral counter ion. Studies of the influence of the mobile phase composition, the solute structure and the mobile phase flow-rate on separation are presented. Under the optimized conditions enantiomeric propanolol, norephedrine, metropolol and salbutamol were separated using dichloromethane-1-pentanol (97:3 v/v) as mobile phase on Lichrospher-100-DIOL column.

Reductive amination of ketones with ammonium catalyzed by a newly identified Brevibacterium epidermidis strain for the synthesis of(S)-chiral amines

The asymmetric reductive amination of achiral ketones with ammonia is a particularly attractive reaction for the synthesis of chiral amines.Although several engineered amine dehydrogenases have been developed by protein engineering for the asymmetric reductive amination of ketones,they all display(R)‐stereoselectivity.To date,there is no report of an(S)‐stereoselective biocatalyst for this reaction.Herein,a microorganism named Brevibacterium epidermidis ECU1015 that catalyzes the(S)‐selective reductive amination of ketones with ammonium has been successfully isolated from soil.Using B.epidermidis ECU1015 as the catalyst,the asymmetric reductive amination of a set of phenylacetone derivatives was successfully carried out,yielding the corresponding(S)‐chiral amines with moderate conversion and>99%enantiomeric excess.

Microbial Production of Chiral Hydroxy Esters and Their Analogs: Biocatalytic Reduction of Carbonyl Compounds by Actinobacteria, <i>Agromyces</i>and <i>Gordonia</i>Strains

We screened 15 Agromyces strains from the Microbacteriaceae family and 16 Gordonia strains from the Gordoniaceae family to investigate their biocatalytic ability to reduce carbonyl compounds. Two Agromyces strains (A. soli NBRC109063 and A. humatus NBRC109085) and two Gordonia strains (G. hydrophobica NBRC16057 and G. malaquae NBRC108250) grew well in 230 medium. The stereoselective reduction of various carbonyl compounds using these four strains was investigated. We discovered that these strains can reduce aliphatic and aromatic α-keto esters and an aromatic α-keto amide. On the basis of the conversion rate and stereoselectivity of the alcohols produced, G. hydrophobica NBRC16057 is a potential biocatalyst for the stereoselective reduction of α-keto esters and an aromatic α-keto amide to the corresponding chiral alcohols. Our results also suggest that the reduction of ethyl 2-methylacetoacetate by wet G. hydrophobica NBRC16057 cells in the presence of L-glutamate is useful for the production of chiral ethyl 3-hydroxy-2-methylbutanoate.

Binol Based Chirality Conversion Reagents for Underivatized Amino Acids

Four binol based pyrrole carboxamide chiral receptors has been synthesized and effectively used as a Chirality Conversion Reagent (CCR) for underivatized amino acids. Three points of interactions take place for the conversion process. They are the reversible imine formation, the internal resonance assisted Hydrogen Bonding (RAHB) and the additional hydrogen bonds between the amino acids and the heterocylic moiety of the pendant groups. The conversion efficiency of all the receptors was found to be comparable with those of the receptors reported earlier.

Preparation of Chiral Hydroxy Esters Using Actinobacteria: Biocatalyst Activity of Marine-Derived <i>Micromonospora</i>and <i>Streptomyces</i>Strains

To research the potential ability of marine-derived actinomycetes to act as biocatalysts, 8 Micromonospora strains and 5 Streptomyces strains were screened. Two recommended media (227 and 1076 media) and 2 modified media (1076-25% and P-1076-25% media) for liquid culture of these marine-derived actinomycetes were tested. As a result, 2 Micromonospora strains (Micromonospora sp. NBRC107096 and 107097) cultured with the 1076-25% medium and 2 Streptomyces strains (Streptomyces tateyamensis NBRC105048 and Streptomyces sp. NBRC105896) cultured with P-1076-25% medium showed a good growth. The stereoselective reduction of α-keto esters using these 4 actinomycetes was tested. As a result, it was found that these strains had a reducing activity toward various α-keto esters. The introduction of L-glutamate or sucrose as an additive remarkably increased the conversion ratios in the reduction of substrates by the Micromonospora strain. Furthermore, in the presence of L-alanine, Streptomyces tateyamensis NBRC105048 reduced ethyl pyruvate, ethyl 2-oxobutanoate, ethyl 2-oxopentanoate, ethyl 2-oxohexanoate, and ethyl 3-methyl-2-oxobutyrate to the corresponding α-hydroxy ester with a high conversion ratio and with excellent enantiomeric excess. Thus, we found that these marine-derived actinomycetes have great potential to be used as biocatalysts for stereoselective reduction of carbonyl compounds.

生物高纯精草:高光学纯L-草铵膦生物制造的创新与发展

草铵膦是全球三大除草剂之一,具有广谱、高活性、非选择性等特点,市场前景被广泛看好。然而,草铵膦具有两种对映异构体(D型和L型),其除草活性主要来自于其中的L型对映体(L-草铵膦)。因此,高光学纯L-草铵膦高效合成至关重要。本文作者团队者研究团队在中国“生物农药之父”沈寅初院士的指导下,开展生物合成L-草铵膦的科学研究和产业化实践长达二十余年,涵盖合成路线重构、生物无机胺化技术建立、生物催化剂创制、产物分离纯化、反应装备、过程智能化控制等方面,开发了“生物高纯精草生产技术”(BioHPP^(®)),建成了万吨级L-草铵膦数字智能化生产线,利用智能传感器和执行器,实现超千个控制点的实时数据采集、传输、分析和反馈调节,全自动化参数采集与控制生产效率提高50%,劳动强度降低70%以上,实现了万吨级L-草铵膦的生物智能制造。本文在研究团队长期积累的基础上,总结和分析了D,L-草铵膦主流生产工艺路线,详述了创新生物制造技术、合成生物技术构筑L-草铵膦关键合成体系的原理和方法,从底物合成与选择、生物催化剂类型、氨基供体使用、分离纯化等方面比较了这些路线的各自特点及实现产业化的关键要点。可以预见,在合成生物技术的助力下,未来将有越来越多的高光学纯度手性农药通过生物制造实现大规模生产。

基于TRIZ理论的酶催化制备手性仲醇工艺改进

手性仲醇在化工制品的合成中总是被作为重要的手性中间体,其光学纯对映体的制备是手性化合物制备过程中的关键步骤。根据现有制备手性仲醇工艺中所存在的收率较低、对映体纯度不高、生产成本高等问题,运用TRIZ理论,按照发现问题、分析问题和解决问题的逻辑,对制备工艺进行优化,提出了一锅法制备手性仲醇工艺,预期有效提高收率和对映体纯度,降低生产成本。为进一步优化制备手性仲醇工艺提供了理论指导和实践参考。

手性胺类医药中间体的绿色合成研究进展

医药生产中普遍存在高污染、高能耗、低效率等问题,急需开发经济、清洁、绿色、低碳的技术。对手性医药中间体进行分类并介绍了含手性胺结构的医药分子,综述了不对称还原胺化法、生物催化法等绿色合成方法应用于手性胺类医药中间体的研究进展,重点阐述了以铵盐、伯胺为氮源的不对称还原胺化法以及利用转氨酶、亚胺还原酶、胺脱氢酶、多酶级联和光-酶级联的生物催化法,并对手性胺类医药中间体领域所面临挑战及发展方向进行了展望。

生物酶在手性胺合成中的研究进展

手性胺类化合物是重要的医药中间体,是多种药物分子的重要结构单元,可通过生物催化的方式制备手性胺化合物。生物催化具有高效、绿色、可持续等优势,对于手性胺的合成以及在医药领域的应用具有重要的促进作用。本文概述了胺脱氢酶和亚胺还原酶在手性胺类化合物合成中的研究进展,着重介绍了天然酶的发现和酶的突变改造等相关研究。此外,还对酶法合成手性胺化合物所面临的挑战进行了总结,并对未来的研究方向进行展望。

固定化脂肪酶手性拆分(R,S)-1-苯基乙醇研究进展

(R,S)-1-苯基乙醇是药物合成与精细化学品的重要中间体,可经固定化脂肪酶不对称催化获得光学纯1-苯基乙醇。本文分别从脂肪酶类型、溶剂工程、固定化技术三方面综述了国内外固定化脂肪酶手性拆分(R,S)-1-苯基乙醇的研究进展,并指明该领域中亟待解决的关键问题及解决思路,以期为后续固定化脂肪酶应用于手性拆分(R,S)-1-苯基乙醇提供参考。