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1.
以L-阿拉伯糖为原料,经过钼酸盐类催化剂发生C-2立体异构化反应,生成以Mo为中心的络合物,C-1的酰基与苯胺反应得到糖胺,糖胺在苯甲酸条件下分解得到L-核糖,收率为30%,用1 H NMR和元素分析对产物进行了表征.  相似文献   

2.
以脂肪酶A为催化剂,水解L-亮氨酸异丁酯制备L-亮氨酸。研究了不同酶、缓冲液体系、物料比、反应温度、反应时间对L-亮氨酸收率的影响,通过正交试验确定了L-亮氨酸异丁酯最佳水解条件。以L-亮氨酸异丁酯为原料,在提取脂肪酶液为Gly-NaOH缓冲液体系、反应前添加L-亮氨酸达到L-亮氨酸溶解度的质量、物料比为1∶13、50℃、摇床转速为170r/min的条件下反应13h,L-亮氨酸的收率为95.23%。  相似文献   

3.
提出了L-苯丙氨酸苄酯盐酸盐合成的新工艺路线,以L-苯丙氨酸为起始原料,先用二碳酸二叔丁酯保护氨基,再与氯化苄缩合得到N-叔丁氧羰基-L-苯丙氨酸苄酯,最后用氯化氢脱保护,得到L-苯丙氨酸苄酯盐酸盐. 通过实验探索了反应温度、原料配比、缚酸剂以及溶剂种类等工艺条件对合成的影响. 实验结果表明,在优化的工艺条件下,合成总收率为90.8%,为L-苯丙氨酸苄酯盐酸盐的合成提供了新选择.  相似文献   

4.
以L-谷氨酸和L-赖氨酸为原料,经7步反应合成得到了具有谷氨酸-脲(Glu-Urea)骨架的前列腺特异性膜抗原小分子抑制剂,除了L-谷氨酸二叔丁基酯的合成,每一步的产率均高于60%,路线总产率为18%。产物经1H NMR,13C NMR及HR-MS(ESI)表征鉴定。针对中间体N6-(9-芴甲氧羰基)-L-赖氨酸叔丁酯的合成设计了一种合成新思路,一步实现了对赖氨酸α氨基的脱保护与羧基的Boc保护,简化了反应步骤,化合物3的合成产率由约20%提升到70%。  相似文献   

5.
探讨了以N-甲酰-L-天冬氨酸酐和L-苯丙氨酸为主要原料制备甜味剂阿斯巴甜中间体(N-甲酰-α-L-天冬氨酰-L-苯丙氨酸)的合成工艺.以乙酸为溶剂,N-甲酰-L-天冬氨酸酐与L-苯丙氨酸进行缩合反应生成N-甲酰-α-L-天冬氨酰-L-苯丙氨酸,考察了乙酸用量、反应温度、时间和N-甲酰-L-天冬氨酸酐与L-苯丙氨酸的比例对反应收率的影响,得到优化的工艺条件为:反应温度40℃,反应时间5 h,乙酸的量为L-苯丙氨酸质量的3.53倍,N-甲酰-L-天冬氨酸酐与L-苯丙氨酸的质量比为0.95:1,此时产物收率达95.46%.并且α-异构体与β-异构体的比例达到75:25.  相似文献   

6.
以L-酪氨酸、乙酰氯为主要原料合成了N-乙酰-L-酪氨酸,再和乙醇与氯化亚砜反应得到的氯化亚硫酸乙酯反应得到N-乙酰-L-酪氨酸乙酯,产物结构经IR、1H NMR确证.单因素试验和正交试验结果表明,N-乙酰-L-酪氨酸乙酯合成的最佳工艺条件为:n(L-酪氨酸)∶n(氯化亚砜)∶n(乙醇)=1∶1.3∶10,加热温度75℃,加热时间2 h.该工艺具有原料价廉易得、反应周期短、产物易分离的特点,适于工业化大规模生产.  相似文献   

7.
以L-(+)-酒石酸和苯甲醇为原料,甲苯为溶剂,硼酸为催化剂的条件下,合成L-(+)-酒石酸二卞酯,分析产物的旋光性,其结构经IR表征.试验得到最佳反应条件为:硼酸用量为0.75 g、反应时间为4 h、甲苯用量40 m L、酸醇摩尔比为1 2.8,产物的比旋光度为+5.325,收率达到83.57%,且硼酸能多次回收利用.  相似文献   

8.
为解决氨基酸金属螯合物采用NaOH调解体系pH值时其反应溶液碱性不易控制的问题,以L-赖氨酸和氯化铜为原料,选用NH3.H2O作为体系pH调节剂,合成了L-赖氨酸铜。单因素平行试验优选法得到L-赖氨酸铜的合成工艺条件为:氯化铜与赖氨酸盐酸盐的摩尔比为3∶5,pH≈8,反应温度为45℃,反应时间为60 min。反应全程在液相中进行,条件温和,避免了因碱性过大而出现沉淀;产品收率为71%;合成的L-赖氨酸铜为蓝色粉末,易溶于水,不溶于乙醇、乙醚等有机溶剂,熔点为227.3~227.5℃。  相似文献   

9.
利用美拉德反应制备鱼味香料   总被引:9,自引:0,他引:9  
以鳙鱼的酶解产物为基料,选择关键氨基酸和还原糖及其恰当配比进行美拉德反应,确定了能产生最逼真鱼香味的反应体系及其最佳配比与反应条件为:还原糖:L-谷氨酸(质量比)2:1;葡萄糖:木糖(质量比)1:2.5;L-谷氨酸:VB1(质量比)1:1;pH值7.0,反应温度115℃,反应时间40min,反应物体积分数40%。  相似文献   

10.
以北京棒杆菌(Corynebacterium pekinense)AS1.299为出发菌株,经复合诱变处理,L-精氨酸结构类似物平板进行抗性筛选,获得了一株L-精氨酸结构类似物抗性菌株FHA0055(D-Argr,SMCr,L-HAr),在糖含量为10%的培养基中,前期30℃,后期32℃,120r/min摇瓶发酵76 h,产L-精氨酸13.25 g/L,较出发菌株提高了140.6%.  相似文献   

11.
1,2,5,6四硝酸甘露醇酯类化合物的合成   总被引:1,自引:0,他引:1  
以海藻中提取的海洋活性物质D-甘露醇为原料,先与丙酮发生缩合反应,将1,2,5,6位羟基保护起来,再对3,4位的羟基分别甲醚化、甲基磺酸和对甲苯磺酸酯化后,脱去异亚丙基保护基团,还原1,2,5,6位的羟基,对其进行硝酸酯化,合成了标题化合物,产率达到了77%以上。合成的中间体和目标产物的结构经红外光谱(IR)、核磁共振氢谱(^1H—NMR)、碳谱(^13C—NMR)和元素分析证实与其分子式相符。此外,还通过质谱(MS)分析对目标产物的分子量进行了分析,结果C35.76%,H3.229/6,S9.45%,N8.309/6与理论值C35.82%,H3.289/6,S9.45%,N8.30完全相符。  相似文献   

12.
探讨了用玉米淀粉制备氧化淀粉,淀粉粘合剂的氧化反应历程和氧化剂进攻部位。研究发现两种反应虽然都是在淀粉团粒的凝胶相进行,但其氧化反应历程不同,氧化剂进攻淀粉链中脱水葡萄糖单元的主要部位也不相同,前者为离子型反应,氧化剂主要进攻C-2,C-3位的仲羟基,而后者为游离基反应,主要进攻C-6位的伯羟基。  相似文献   

13.
对黄芩素作结构修饰,利用黄芩素8位α氢的活泼性,通过Mannich反应引入了各种胺甲基类基团,合成并鉴定了3个Mannich碱衍生物,同时针对6、7位羟基进行修饰,分离鉴定出2个衍生物.该类反应条件温和,制备方法简便,产品收率高,是一种通过引入亲水性基团对黄芩素母核进行结构修饰,进而改善黄芩素类化合物水溶性以提高其生物利用度的有效方法.  相似文献   

14.
对N,N-二乙基二硫代氨基甲酸烯丙基酯(ADC)的1HNMR谱,13CNMR谱及H-1H.13C-1H化学位移相关谱测定结果进行了讨论。对13CNMR和1HNMR谱峰作出了归属,并确认了ADC的链结构。  相似文献   

15.
An acrylate emulsion was modified by adding vinyltriisopropoxy silane (trade name C-1706). By adding the multiple emulsifier which consists of an anionic emulsifier, sodium dodecyl benzene sulfonate (SDBS) and nonionic emulsifier, octyl phenolic divinyl oxide (OP-10), the acrylosilane microemulsion was synthesized by seeded emulsion polymerization. The influential factors including the kind and the adding amount of emulsifiers and the monomer variety of alkoxy silane and the added methods which influence on the properties of the microemulsion were investigated. It is found that SDBS and OP-10 as multiple emulsifiers with mass ratio of 1:1 and the adding amount of 2.5%-3.5% can act on co-effect for emulsion polymerization. The C-1706 possesses bulky isopropoxy substituent that can reduce hydrolysis reactivity during the polymerization process, so as to not only make the process smoothly but also advance the store stability of the emulsion. Moreover, the latter-addition mode of C-1706 can restrain its hydrolysis activity and polycondensation reaction during the polymerization process of the emulsion. The structure, the film cross section, the particle size and its distribution of the microemulsion were analyzed by the Fourier Transform Infrared Ray Spectrum (FTIR), Scanning Electron Microscopy (SEM) and a particle size analyzer, respectively. The results show that the particle diameter of the modified microemulsion can be controlled between 50 and 70 nm and its film hardness is 7.3. Only adding 1.5% of C-1706 into the system of emulsion polymerization can apparently improve the weathering resistance of the microemulsion, which undergo degradation with chromatism(△E) is 1.6 after 3 600 hours of QUV-aging.  相似文献   

16.
壳寡糖可以抑制多种病原微生物的生长,其抑菌活性与其数均相对分子质量有密切关系.由专一性的壳聚糖混合酶、内切酶和外切酶降解制备3种不同数均相对分子质量的壳寡糖C-1、C-2和C-3样品,通过抑制生长速率的方法,研究了3种壳寡糖对几种常见植物病原菌的拮抗作用,并采用抑菌圈法测定了壳寡糖对植物病原菌的最低抑菌质量浓度.结果表明,C-1和C-2都有较好的抑菌活性,C-2的抑菌活性明显优于C-1,C-3基本上没有抑菌活性,反而促进了植物病原菌的生长.抑菌效果因壳聚糖酶的酶切方式、壳寡糖的质量浓度和供试菌种而异.  相似文献   

17.
本文研究正戊醇、异戊醇与硫酸反应动力学,测定了反应速率常数和活化能。  相似文献   

18.
The liquid structure of Fe-4.30C and Fe-4.30C-0.21Ce alloys was studied by high temperature X-ray diffractometer. The results show that for Fe-C alloy the nearest neighbor distance of the eutectic alloy is 0.259-0.260 nm at the temperature range of 1200-1400℃, which increases to 0.269-0.271 nm with the addition of 0.21% (mass fraction) Ce in the Fe-C alloy at the same temperature range. There is a pre-peak at Q = 15.5 nm-1 on the original intensity curve and structure factor S(Q) of the liquid Fe-4.30C-0.21Ce alloy, which was caused by the Ce atoms in the C-Ce clusters. Combined with the shared face, the tetragonal structure can meet the requirement for the distance of Ce-Ce atoms. It also shows that the cluster size in the liquid Fe-4.30C-0.21Ce alloy increases with the decreasing temperature.  相似文献   

19.
17α-actoxy-19-nor-progesterone was synthesized by a new efficient stereoselective asymmertric pathway from 19-nor-androst-4-en-3,17-dione in 5-steps reactions with overall yield 63.3%. Consequently, a strategy was used to produce of 17-α-hydroxyl compound stereoselectively by addition 17-keto steroid with hydrogen cyanide, at the same time, the conditions of this asymmertric reaction were optimized. The titled compound and the intermediate were fully characterized by 1H, one dimension and two dimension 13C-nuclear magnetic resonance, and infrared spectrum. The results show that the rate of 17-α-hydroxyl compound isomeride is sensitively affected by the solution system and the best volume ratio of CH3 OH to H2 O is 36%. After the carbonyl and hydroxyl groups were protected by ethylenediol and vinyl butyl ether respectively, organometallic addition to CN group with CH3 Li, androstance compound was converted to pregnane compound. After removing the protective groups by a mild hydrolytic procedure with high yield, the titled compound was obtained by esterified the above intermidiate. The new pathway gives a good purity of 98% as determined by high performance liquid chromatography.  相似文献   

20.
纤维素降解菌绿色木霉C-08产酶条件研究   总被引:4,自引:0,他引:4  
为了确定绿色木霉C-08菌株的最佳产酶条件,对从土壤中筛选到一株具有较高纤维素酶活性的绿色木霉的液态发酵条件进行了优化,结果表明,麸皮和稻草作为最佳碳源可较大幅度地提高纤维素酶的产量,C-08的最佳麸皮和稻草质量比为5∶2.C-08株菌的最佳无机、有机氮源为(NH4)2SO4和豆饼粉,最佳无机、有机氮源比为1∶5.最适宜的碳氮比为5∶1,质量分数为3.6%.产酶的最适宜温度为30℃,最佳产酶pH为3.2,最佳产酶时间为96h.  相似文献   

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