共查询到19条相似文献,搜索用时 609 毫秒
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建立了利用高效液相色谱对葡萄糖发酵产2-酮基-L-古龙酸体系中的4种代谢产物D-葡萄糖酸、2-酮基-D-葡萄糖酸、2,5-二酮基-D-葡萄糖酸和2-酮基-L-古龙酸的定量测定方法,分析条件为:300 mm′7.8 mm Aminex HPX-87H柱,柱温30℃,流动相为50 mmol/L硫酸,流速0.2 mL/min,RID-10A示差检测器,以丙二酸为内标物. 结果表明,4种物质分离较好. 该方法对2-酮基-D-葡萄糖酸、2,5-二酮基-D-葡萄糖酸和2-酮基-L-古龙酸3种代谢物的检测平均误差分别为1.53%, 0.89%和1.84%. 相似文献
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研究了一种以草酸二乙酯、异丁醛和甲醛为原料合成酮基泛内酯,再通过催化加氢合成α-羟基-β,β-二甲基-γ-丁内酯的清洁工艺,并用核磁共振、红外及色质联用对产品的结构进行了表征。 相似文献
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泛解酸内酯是合成D-泛酸钙和D-泛醇的重要中间体,国内主要采用生物拆分法,虽取得一定进展,但存在底物浓度偏低、反应条件苛刻、光学纯度不高和催化剂活性不强等问题。化学不对称合成法成为近年来制备手性泛内酯的研究热点。根据手性源的不同,介绍过渡金属配合物催化不对称还原酮基泛内酯,过渡金属配合物催化羟醛缩合反应,有机小分子及其衍生物不对称催化羟醛缩合反应并经还原内酯化合成泛内酯以及光学活性化合物作为反应底物或非手性底物中加入手性助剂的合成手性泛内酯工艺。其中,有机小分子催化乙醛酸酯与醛的反应表现出良好的催化效果,且催化剂易得,反应条件温和,操作简单。缩合产物的收率和对映选择性均不高,设计具有高活性和高选择性的有机小分子手性催化剂是今后研究的重点。 相似文献
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韩文 《精细化工原料及中间体》2006,(3):15-17
泛酸钙,化学名为N-(α,γ-二羟基-β,β-二甲基丁酰)-β-氨基丙酸钙,是水溶性维生素B族的一种,也是生物正常生长必需的营养物质之一。泛酸钙有三种形式,即D-泛酸钙(右旋)、DL-泛酸钙(混旋)和L-泛酸钙(左旋),其中仅D-泛酸钙具有生物活性。泛酸钙进入体内可释放出泛酸和钙元素,而泛酸作为辅酶A前体物质,进而转化为辅酶A而产生诸多生理作用。泛酸钙以其特有的生化功能广泛应用于饲料、医药、食品等工业。1D-泛酸钙生产现状1.1生产工艺D-泛酸钙的制备方法较复杂,首先要制备两个重要的中间体,分别为β-氨基丙酸和DL-泛解酸内酯。由上述中间… 相似文献
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合成新型甾体激素类化合物依普利酮(eplerenone)。以17β-羟基-3-氧代-11α-甲磺酸基-17α-孕甾-4-烯-7α,21-二羧酸,γ-内酯,7-甲酯(甲磺酸酯)为原料,经消除、环氧化反应得(7α,11α,17α)-9,11-环氧-17-羟基-3-氧代-孕甾-4-烯-7,21-二羧酸,γ-内酯,7-甲酯(依普利酮)。合成出依普利酮。经相关谱图(IR、1H-NMR)的表征,合成的化合物为目标化合物。 相似文献
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在利用微生物氧化合成维生素C(VC)的研究方面,阐述了微生物通过以D-山梨醇和D-葡萄糖为底物进行生物转化的代谢途径,以合成维生素C前体--2-酮基-L-古龙酸(2-KGA)的研究现状和发展趋势。 相似文献
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生物技术法制备D-泛酸钙和D-泛醇 总被引:4,自引:0,他引:4
综述了发酵法和酶法制备D 泛酸钙和D 泛醇的研究概况 ,详述了不对称还原酮基泛解酸内酯、微生物选择性水解L 泛解酸内酯 /D 泛解酸内酯的工艺 ,并对微生物酶法拆分生产D 泛解酸内酯工艺的产业化情况进行了介绍。 相似文献
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催化氢化合成三羟甲基丙烷 总被引:4,自引:1,他引:3
通过羟醛缩合,加氢催化两步反应,对三羟甲基丙烷的合成进行了研究。重点研究了影响羟醛的缩合反应,加氢还原的有关因素,如羟醛缩合反应中的催化剂用量,滴加温度,反应温度和时间,催化加氢中的催化剂性能,溶剂的选择等。 相似文献
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甲基丙烯酸甲酯(MMA)是一种重要的基础有机化工原料,主要用于生产有机玻璃、塑料改性剂及表面涂料等诸多行业,具有非常广阔的发展前景,MMA 合成路线众多。本文综述了以乙烯为起始原料,经过羰基化反应制备丙醛、丙酸和丙酸甲酯等中间产物,然后经羟醛缩合反应制备MMA的研究进展。概述了乙烯制备MMA的3条工艺路线及其发展趋势,指出中间产物与甲醛的缩合反应是乙烯路线的关键步骤,重点介绍了羟醛缩合反应及其催化剂的研究现状。目前用于气相催化羟醛缩合反应的催化剂主要有V、Si、P酸性催化剂和K、Cs碱性催化剂,其中以Cs为主活性组分的碱性催化剂研究最为广泛,载体种类、助剂、制备方法、反应条件等对催化剂的活性、选择性和寿命等具有较大影响。为进一步改善催化剂的性能,需加强对羟醛缩合反应催化机理的研究,具有酸碱两性的复合催化剂是今后重点研究方向。 相似文献
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The organoiron complex 4 is readily prepared from α-bromopyruvic ester diethyl acetal, and has been shown to serve as an effective α-acrylic ester cation equivalent, in the synthesis of α-methylene-γ-lactones. Cyclohexanone lithium enolate is transformed to either the cis or trans fused lactones 12c , t, and ethyl acetoacetate lithium enolate can be converted to the lactone 21 t. The use of methyl 3-oxohexadecanoate as starting material provides a stereospecific synthesis of protolichesterinic acid methyl ester. 相似文献
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Chein-Shyong Su Chin-Ping Yang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1990,48(3):313-323
Selected specific α-amylase and glucoamylase enzymes were immobilized and combined with immobilized cyclodextrin glycosyltransferase to continuously produce cyclodextrin (CD). The liquefied starch was cyclized to CD by ICGTase and then treated by immobilized α-amylase and glucoamylase to contain CD and glucose only. β-CD and soluble CD (α- and γ-CD) in the final CD solution could be easily separated. The pH-activity curve, temperature-activity curve, batch re-usability and continuous operation stability of immobilized enzymes were discussed. The continuous production of CD by an immobilized enzyme system was also reported. The optimal conditions for using immobilized α-amylase and glucoamylase simultaneously were 40°C and pH 4.5 adjusted by 1 mol dm?3 HCl/NaOH. A 70% yield of CD could be obtained from 1% (w/v) of liquefied starch under continuous operation at 0.055 h?1 space velocity, and almost all the oligosaccharides (β 98%) were converted to glucose. In this study, the separation of α-CD, γ-CD and glucose, using organic solvent from the final product after precipitating β-CD, was also investigated. 相似文献
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Vanja Kaswurm Wouter Van Hecke Klaus Dieter Kulbe Roland Ludwig 《Advanced Synthesis \u0026amp; Catalysis》2013,355(9):1709-1714
Glucose dehydrogenase (GDH) is frequently used for the reduction of NAD+ and NADP+ in bench‐ and industrial‐scale syntheses because the coenzyme regenerating system GDH is easy to apply, robust and relatively inexpensive. To optimize the application of this long known coenzyme regeneration system we investigated the commonly applied Bacillus GDH and characterized this enzyme by its kinetic features in the presence of substrates and products at pH 6.4 and 8.0. Three substrates/products were found to inhibit GDH considerably: (i) the reaction product glucono‐1,5‐lactone, (ii) the reduced coenzyme NAD(P)H and (iii) the oxidized coenzyme NAD(P)+. The inhibition of GDH under several process conditions was modeled using the determined kinetic constants. It was found that the GDH regeneration system is strongly inhibited by the usually applied conditions. This study provides the rate equation of the GDH reaction and simulations of this coenzyme regenerating system leading to an improved prediction and, thus, to a faster scale‐up and increased efficiency of NAD(P)H‐dependent synthetic processes. 相似文献
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