共查询到20条相似文献,搜索用时 156 毫秒
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氟化铝是金属氟化物中最具代表性的一类无机材料,具有L酸中心,广泛用作催化剂或催化剂载体,主要应用于氟氯烃及其ODS替代品的气固相催化合成。高比表面积氟化铝具有更多的表面L酸中心。综述了近年国内外高比表面积氟化铝合成的研究成果,评述了高比表面积无定形AlF3和晶型AlF3(β-AlF3、α-AlF3和γ-AlF3等)的合成方法,分析了溶胶-凝胶法、气相氟化法和加热分解法等方法对高比表面积氟化铝合成的影响。分析了高比表面积氟化铝合成中存在的一些问题,展望了高比表面积氟化铝合成的发展趋势和应用。 相似文献
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本文探索了一条基于钯催化的、通过β-偕二氟氨基酸衍生物与杂环硼酸的Suzuki交叉偶联反应,制备氨基酸衍生物的合成路线。合成路线的起始原料是二苄胺和溴乙酸乙酯,经过胺醛缩合反应、亲核加成反应、羟基Appel溴化反应、heck重排、Suzuki还原交叉偶联等5个反应步骤,成功合成了2-(苄基(3-(4-(呋喃-3-基)苯基)烯丙基)氨基)-3-苯基己酸乙酯等氨基酸衍生物。该合成路线的起始原料价廉易得,合成步骤简便,具有清洁易操作、条件温和等优点,可为非天然氨基酸的合成提供参考。 相似文献
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稀土固体超强酸SO2-4/TiO2/La3+催化合成醋酸丁酯 总被引:13,自引:0,他引:13
《化学世界》2001,42(12):653-654
研究了以固体超强酸SO24-/TiO2/La3+催化剂,醋酸和正丁醇为原料合成醋酸丁酯,并考察了影响反应的因素.结果表明醇酸物质的摩尔比为1.61、催化剂用量0.6
g、带水剂甲苯7 mL、反应时间2.5 h是最适宜的反应条件,其酯化率可达96.2%. 相似文献
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以苯甲醛和氯乙酸乙酯为原料,经Darzens缩合反应生成反式-3-苯基缩水甘油酸乙酯,然后用氨水开环得赤型-3-苯基异丝氨酰胺,再以苯甲酰氯酰化得赤型-N-苯甲酰基-3-苯基异丝氨酰胺,用甲醇酯化生成赤型-N-苯甲酰基-3-苯基异丝氨酸甲酯,最后水解即得目标产物赤型-N-苯甲酰基-3-苯基异丝氨酸。 相似文献
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Marek Krl Grzegorz
lifirski Jerzy Kleps Piotr Podsadni Ilona Materek Anna E. Kozio Franciszek Herold 《International journal of molecular sciences》2023,24(1)
This article describes the synthesis of new chiral 3-(piperidin-3-yl)-1H-indole derivatives (R)-10a-c and (S)-11a-c from the corresponding diastereomers: (3R, 2R) and (3S, 2R)-2-[3-(1H-indol-3-yl)-1-piperidyl]-2-phenyl-acetamides (3R, 2R)-4a, (3R, 2R)-6b, (3R, 2R)-8c and (3S, 2R)-5a, (3S, 2R)-7b, (3S, 2R)-9c. Diastereomers were obtained by N-alkylation of derivatives of racemic 3-(piperidin-3-yl)-1H-indoles 1a-c using (S)-2-(4-toluenesulfonyloxy)-phenylacetic amide (S)–II. The same method was applied to obtain (3R, 2S)-methyl-2-[3-(1H-indole-3-yl)-1-piperidyl]-2-phenylacetate (3R, 2S)-2a and (3S, 2S)-methyl-2-[3-(1H-indole-3-yl)-1-piperidyl]-2-phenylacetate (3S, 2S)-3a diastereomers by treating amine 1a with (R)-2-(4-toluenesulfonyloxy)-phenylacetic acid methylester (R)-I. Systematic studies via single crystal X-ray crystallography were used to determine the molecular structure of the racemates 1a-c and the absolute configuration of the enantiomers. The solid racemates 1b and 1c were “true racemates” crystallizing in a centrosymmetric space group, while 1a formed a racemic conglomerate of homoenantiomeric crystals. The absolute configuration was determined for the enantiomeric pairs (R)-10a/(S)-11a, (R)-10b/(S)-11b, and (R)-12c/(S)-13c, as well as for (3S,2S)-3a. Spectra of 1H, 13CNMR, HPLC, and HRMS for diastereomers and enantiomers were consistent with the determined structures. 相似文献
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亚磷酸三乙酯与氯乙酸乙酯进行缩合、重排、脱氯乙烷合成磷酸酯,再与对氟苯甲醛经Knoevenagel反应合成肉桂酸酯,肉桂酸酯与丙二酸二乙酯胺解合成的N-甲胺基羰基乙酸乙酯环合得到哌啶二酮,环化物用硼氢化钾复合还原剂还原得±4-(4-氟苯基)-3-羟甲基-1-甲基哌啶,把混旋体进行手性拆分得目标产物(-)反式-4R(4-氟苯基)-3-羟甲基-1-甲基哌啶。选择自制硅胶酸载催化剂Cat1#、醋酸-乙二胺催化剂Cat2#、复合相转移催化剂Cat3#为各步催化剂,反应收率分别为89.1%、96.3%、86.5%、76.3%、87.2%、43.7%,总收率24.3%,比旋光度-36 ̄-38°,纯度大于99%。 相似文献
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Huang LF Su B Jao SC Liu KT Li WS 《Chembiochem : a European journal of chemical biology》2006,7(3):506-514
The activity of the aminopeptidase P from Escherichia coli in hydrolyzing a series of organophosphonate sarin analogues (1-6) was evaluated. The enzymatic rates of hydrolysis for methylphosphonate 1 with a methoxy group attached to the phosphorus center were 7- to 15-fold higher than those for the corresponding analogues 2-6. Double mutant R153W/R370L was able to hydrolyze the S(p) enantiomer of racemic 1 at a considerable rate. This mutant allowed the preparation of the R(p) isomer of the sarin analogue 1. All the mutants, R370L, R153A, W88L, R153L/R370L, and R153W/R370L, preferred the formation of (S(p))-8 to that of the corresponding (R(p))-8 enantiomer and displayed a better enantiomeric excess of products, by 1.4- to 2-fold as compared to the wild-type enzyme. Enzymatic hydrolysis of O,O-diisopropyl-p-nitrophenyl phosphate (9) in H(2) (18)O led to the formation of the (18)O-labeled O,O-diisopropyl phosphate product and confirmed that the catalytic reaction starts with cleavage of the P--O bond. From chemical and kinetic studies, the utilization of an optically pure S(p) enantiomer of O-methyl-p-nitrophenyl methylphosphonothioate (S(p))-MNMPT, 7) has demonstrated that the enzymatic reaction proceeds through a displacement mechanism and generates a chiral product in situ with an inversion of stereochemical configuration at the phosphorus atom. The results also lead to the conclusion that alteration of the active site through site-directed mutagenesis can result in a preference for (S(p))-MNMPT (7) rather than the R(p) isomer. 相似文献
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Zada A Ben-Yehuda S Dunkelblum E Harel M Assael F Mendel Z 《Journal of chemical ecology》2004,30(3):631-641
Stereoisomers of 4-methyl-3-heptanol are major components of aggregation pheromones of bark beetles and trail pheromones of ants. Recently, (3S,4S)-4-methyl-3-heptanol (I) has been tentatively identified as the main component of the aggregation pheromone of the almond bark beetle, Scolytus amygdali (Coleoptera: Scolytidae). The four stereoisomers of 4-methyl-3-heptanol were prepared and bioassayed. Key steps included preparation of chiral 4-methyl-3-heptanones using SAMP and RAMP reagents, reduction to the corresponding alcohols, and stereospecific transesterification with vinyl acetate with lipase AK catalysis. In field tests, only (3S,4S)-4-methyl-3-heptanol attracted beetles in combination with the synergist (3S,4S)-4-methyl-3-hexanol, whereas (3R,4S)- and (3R,4R)-4-methyl-3-heptanols were inhibitory. 相似文献
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本文以异香草醛为原料经过5步反应合成了Aliskiren的一个重要中间体——(R)-2-[4-甲氧基-3-(3-甲氧基丙氧基)苄基]-3-甲基丁酸。醚化中采用超声波反应,缩短了反应时间,提高了产率。所需手性中心由(R)-3-异戊酰基-4-苄基-2-噁唑烷酮诱导产生,针对去除诱导剂时需断裂环外酰胺键,通常会先引起分子中的酯键断裂,因而很难将诱导剂断裂下来,实验采用氢过氧化锂(LiOOH)高选择性地断裂环外酰胺键,实验还选用钙盐沉淀法纯化目标产物,均取得良好的效果。 相似文献
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W. Werner D. Tresselt W. Ihn G. Ziebell 《Advanced Synthesis \u0026amp; Catalysis》1987,329(6):1031-1037
Resolution of the Enantiomers of (S,R)-1,1′-Bi-2,2′-naphthylhydrogenphosphate by (1R,2R)- and (1S,2S)-2-Amino-1-(4-nitrophenyl)-propane-1,3-diol The resolution of the diastereoisomeric salts of the title compounds was possible in the presence of a ketone, especially acetone, which forms oxazolidines ( 3a–d ) with the chiral bases. These oxazolidines afforded separable salts with the (S,R)-1,1′-Bi-2,2′-naphthylhydrogenphosphate ( 4 ). The structures of these salts were proved by m.s. and n.m.r. spectroscopy. 相似文献