Large-Scale Asymmetric Synthesis of Fmoc-(S)-2-Amino-6,6,6-Trifluorohexanoic Acid

Here we report the first large-scale synthesis of Fmoc-(S)-2-amino-6,6,6-trifluorohexanoic acid via asymmetric alkylation of chiral Ni(II)-complex of glycine Schiff base with CF₃(CH₂)₃I. The synthesis was performed on over 100 g scale and can be recommended as the most advanced procedure for reliable preparation of large amounts of enantiomerically pure Fmoc-(S)-2-amino-6,6,6-trifluorohexanoic acid for protein engineering and drug design. Chiral auxiliary used in this protocol can be >90 % recovered and reused.     

Sulfamic Acid: Efficient,Cost-Effective Catalyst for Facile Synthesis of Deazaoxaflavin at Ambient Temperature

A facile, ecofriendly procedure has been developed for the synthesis of substituted 5-deaza-10-oxaflavins by sulfamic acid–catalyzed two-component condensation of salicylaldehyde and barbituric acid at ambient temperature. Mild reaction conditions, short reaction time, ambient temperature, ecofriendly solvent system, wide substrate scope, simple workup procedure, no need for chromatographic separation, and good yields are auxiliary advantages of the present protocol.     

Improved One-pot Synthesis of 4,6-Dihydroxyisophthalic Acid and 2,3-Dihydroxyterephthalic Acid

An improved method for the large-scale preparation of 4,6-dihydroxyisophthalic acid and 2,3-dihydroxyterephthalic acid has been developed.Compared to the previous procedures,this new process-requires much lower CO2 pressure of 0.3 Mpa and shorter reaction time.thus providing a convenient access for large-scale synthesis.The yield is high （93% and 65%,respectively）, and the oxidation of phenol is nearly inhibited,neither decolorization nor further chromatographic purification is required.     

大黄酚和大黄酸的合成

以3-硝基邻苯二甲酸为原料,经脱水、傅克酰基化、还原、重氮化、水解和环合反应合成了大黄酚(6),总收率40.4%。6再经乙酰化、氧化、脱乙酰化反应合成了大黄酸(8),总收率22.3%。6和8的结构经1H NMR表征。     

阿魏酸的合成和应用

介绍了阿魏酸的结构、性质、合成方法,其中生物合成法具有广阔的开发和应用前景。阿魏酸因其独特而优良的药理活性在食品、保键品、化妆品、医药等方面有着广泛的用途。     

三氧化硫脲的合成

三氧化硫脲 (Aminoiminomethanesulfonicacid,简称 AIMSO3H)是十分有效的脒化试剂 ,它可在温和条件下将氨基转化成胍基 [1,2 ] . 1 965年Debowski[3] 报道了 AIMSO3H的合成 .此后 ,Miller[1] ,Kim等 [2 ]又相继报道了它的合成及物理常数 .他们多以硫脲或二氧化硫脲为原料 ,以过氧乙酸为氧化剂 .本文报道用 H2 O2 作氧化剂的合成方法 ,并对其热稳定性进行了研究 .二氧化硫脲 ,由烟台化工总厂提供 ,经重结晶提纯至 99.98% [5] ;市售 30 % H2 O2 试剂 .取 65m L H2 O2 于烧杯中 ,加入 1 .7m L浓硫酸 ,搅拌 ,配成 H2 O2 酸性溶液 .在…     

Concise Synthesis of Ximenynic Acid

Abstract

An improved synthesis of ximenynic acid (1) starting from castor oil has been developed with the direct chlorination of ricinstearolic acid as the key step. By this modification, the synthetic route was more concise and economic. The separation of geometric somers was achieved by repeated urea fractionation.

Supplemental materials are available for this article. Go the publisher's online edition of Synthetic Communications to view the free supplemental file.     

Synthesis of Δ-OPC-8:0 and OPC-6:0

CuCN-catalyzed reaction of the (1R)-isomer of 4-cyclopentene-1,3-diol monoacetate with TBDPSO(CH₂)₆MgCl produced an S_N2-type product regioselectively in high yield. Mitsunobu inversion of the product and subsequent Claisen rearrangement furnished aldehyde with the two side chains, from which the title compounds were synthesized efficiently.     

聚天冬氨酸的合成

以马来酸酐和碳酸铵为原料,合成了高纯度的聚天冬氨酸(PASP),其结构经IR,TG-DTA等表征。优化反应条件为:马来酸酐200 mmol,n(马来酸酐)∶n(碳酸铵)=1.0∶1.2,于180℃反应1.0 h,收率98.11%,PASP的分子量为8 600。     

对三氟甲基肉桂酸的合成

以对三氟甲基苯胺为原料,经重氮化和缩合反应合成了高纯度的对三氟甲基肉桂酸,总收率41.4%。其结构经1H NMR表征。     

牛磺熊去氧胆酸的合成研究

以熊去氧胆酸为原料，先与氯甲酸乙酯形成混酐，再与牛磺酸反应合成牛磺熊去氧胆酸。通优化反应条件、简化后处理等工艺改进，提高了收率，得到了较高纯度的结晶产品。     

Sulfamic Acid: A Mild,Efficient, and Cost-Effective Catalyst for Synthesis of Indoloquinoxalines at Ambient Temperature

A simple, cost-effective method for synthesis of indoloquinoxalines from isatin and o-phenylenediamine employing a catalytic amount of sulfamic acid at ambient temperature is reported. Moreover, the method is applicable for a variety of isatins, ninhydrin, 4-hydroxynaphthaquinone, and 1,2-diketones. The key features of the protocol include rapid reactions with good yields, simple workup procedure, and easy isolation of products.     

Lysophosphatidic acid receptor 2 and Gi/Src pathway mediate cell motility through cyclooxygenase 2 expression in CAOV-3 ovarian cancer cells

Lysophosphatidic acid (LPA) is a bioactive phospholipids and involves in various cellular events, including tumor cell migration. In the present study, we investigated LPA receptor and its transactivation to EGFR for cyclooxygenase-2 (COX-2) expression and cell migration in CAOV-3 ovarian cancer cells. LPA induced COX-2 expression in a dose-dependent manner, and pretreatment of the cells with pharmacological inhibitors of Gi (pertussis toxin), Src (PP2), EGF receptor (EGFR) (AG1478), ERK (PD98059) significantly inhibited LPA-induced COX-2 expression. Consistent to these results, transfection of the cells with selective Src siRNA attenuated COX-2 expression by LPA. LPA stimulated CAOV-3 cell migration that was abrogated by pharmacological inhibitors and antibody of EP2. Higher expression of LPA2 mRNA was observed in CAOV-3 cells, and transfection of the cells with a selective LPA2 siRNA significantly inhibited LPA-induced activation of EGFR and ERK, as well as COX-2 expression. Importantly, LPA2 siRNA also blocked LPA-induced ovarian cancer cell migration. Collectively, our results clearly show the significance of LPA2 and Gi/Src pathway for LPA-induced COX-2 expression and cell migration that could be a promising drug target for ovarian cancer cell metastasis.     

聚天冬氨酸的合成

缓蚀阻垢;热稳定性;水解稳定性;生物降解性;聚天冬氨酸的合成     

用三氧化硫脲合成氨基胍

氨基胍是重要的精细化工原料 ,广泛应用于医药、农药、发泡剂和染料等多种精细化学品的合成 ,近年来大量应用于阳离子染料合成 .由氨基氰与肼在水溶液中反应制备氨基胍已有报道 .但现行工业方法生产氨基胍收率和产品纯度均比较低 [1] .三氧化硫脲 ( Aminoiminomethanesulfonicacid,简称 AIMSO3H)自 1 965年问世以来研究很少 .本文讨论用三氧化硫脲与水合肼作用合成氨基胍 .合成手续简单 ,收率和产品纯度均较高 .仪器和试剂 :Nicolot公司 MAGAN- 5 5 0( series )型红外分光光度计 ,GRT- 1型差热分析仪 (上海天平仪器厂 ) ,p Hs- 2型酸…     

Studies on the Total Synthesis of Crotocembreneic Acid and Neocrotocembreneic Acid:A Perchloric Acid-induced Lactonization Reaction of Epoxy Ester

Cembranoids, a large family of diterpenoid natural products characterized by the presence of fourteen-membered ring, have been isolated from various marine sources as well as some terrestrial organisms since the 1960's1. Crotocembraneic acid 1 and neocrotocembraneic acid 2 have been isolated from the stem bark of Croton oblongifolius Roxb. (Euphorbiaceae)2. In our studies on the total synthesis of 1 and 2, we find a novel perchloric acid-induced lactonization reaction of epoxy ester 9 (Scheme…     

2-氯烟酸的合成

以3-氰基吡啶(2)为原料,经氧化、氯化和水解反应合成了2-氯烟酸(1),总收率75.1%,其结构经IR和MS表征.最点考察了影响氧化反应的因素,最佳氧化反应条件为: 2 410 mmol,n(H2O2) ∶ n(2)＝1.2 ∶ 1.0,在钨酸盐催化下于70 ℃反应8 h,收率92.2%.     

Convenient Synthesis of Dicyclohexyldithiophosphinic Acid

Dicyclohexyldithiophosphinic acid was synthesized by a three-step strategy through the Grignard reaction of PSCl₃ with cyclo-C₆H₁₁MgBr and the P-P bond-cleavage reaction of the intermediate. The ¹H NMR data of ammonium dicyclohexyldithiophosphinate 4 and dicyclohexyldithiophosphinic acid 5 were characterized by ¹H-¹H correlation spectra.     

脱落酸的全合成

脱落酸是一种广泛存在于植物体内的抑制性植物激素,与植物离层形成、诱导休眠、抑制发芽、促进器官衰老和脱落、增强抗逆性等密切相关。本文简要综述了脱落酸的全合成路线,并对各路线的优劣与存在的问题进行了分析、比较。     

乙醇酸的合成及应用

综述了乙醇酸的合成方法,分离提纯以及在有机合成和生物中的应用,参考文献25篇。