Synthesis of a chito-tetrasaccharide β-1,4-GlcNAc-β-1,4-GlcN repeating unit

Abstract  

tert-Butyldimethylsilyl (4-O-acetyl-2-azido-3,6-di-O-benzyl-2-deoxy-β-d-glucopyranosyl)-(1 → 4)-3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranoside (Kawada and Yoneda [MOCHEM-D-09-00120], 2009), designed as a repeating disaccharide unit in a β-glucan having two different faces, was converted into a glycosyl donor and an acceptor. The glycosyl acceptor was glycosylated with the donor to afford a chito-tetrasaccharide derivative in good yield. Phthalimido and azido groups in the tetrasaccharide were successively converted into acetamido and free amino groups, and all other protecting groups were cleaved to obtain the chito-tetrasaccharide (2-amino-2-deoxy-β-d-glucopyranosyl)-(1 → 4)-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1 → 4)-(2-amino-2-deoxy-β-d-glucopyranosyl)-(1 → 4)-2-acetamido-2-deoxy-d-glucopyranose.     

手性β-氨基醇催化α,β-不饱和酮的不对称环氧化反应

将以烯烃为原料通过Sharpless不对称双羟化等多步反应合成的8种手性β-氨基醇, 作为有机小分子催化剂, 用于催化α,β-不饱和酮的不对称环氧化反应．考察了影响对映选择性的催化剂结构、催化剂用量、氧化剂种类、溶剂、反应温度等因素．结果表明, 当催化剂用量为30 mol%、氧化剂为TBHP(叔丁基过氧化氢)、正己烷溶剂、在室温下、以(1S,2R)-(＋)-1,2-二苯基-2-甲氨基乙醇(3)作催化剂时, 所得环氧化物的对映体过量最高为70% ee, 产率最高为84%.     

α-酮酯和α-酮酰胺的Henry反应

用三乙胺催化环状α-酮酯和α-酮酰胺同硝基甲烷的Henry反应, 首次合成了12个多官能团的β-硝基醇, 它们的结构用元素分析、红外光谱和核磁共振进行了表征. 这一反应速度较快, 室温下进行, 条件温和, 产率较好, 是合成多官能团硝基醇的有效方法.     

4d-4f异金属配位聚合物的合成、结构和荧光性质

在水热反应条件下成功地合成了3个4d-4f异金属化合物{[LnAg₂(QA)₄(H₂O)₅](ClO₄)}_n(Ln=Nd(1),Tb(2),Eu(3);HQA=3-喹啉羧酸)。用单晶衍射分析,元素分析和粉末衍射分析对晶体结构进行了表征。化合物1~3同构,在bc平面形成二维层结构,抗衡离子ClO₄^-与二维层通过氢键作用形成三维超分子结构。研究了配合物2和3的荧光性质。     

4d-4f异金属配位聚合物的合成、结构和荧光性质

在水热反应条件下成功地合成了3个4d-4f异金属化合物{[LnAg2(QA)4(H2O)5](ClO4)}n(Ln=Nd(1),Tb(2),Eu(3);HQA=3-喹啉羧酸)。用单晶衍射分析,元素分析和粉末衍射分析对晶体结构进行了表征。化合物1~3同构,在bc平面形成二维层结构,抗衡离子ClO4-与二维层通过氢键作用形成三维超分子结构。研究了配合物2和3的荧光性质。     

2-(N'-乙基咔唑-3'-烯基)-8-羟基喹啉的合成及理论研究

设计合成了2-(N'-乙基咔唑-3'-烯基)-8-羟基喹啉. 以UV-Vis, ¹H NMR, FT-IR, 元素分析和MS进行了结构表征, 并测定了产物的光致发光(PL)性质. 运用Gaussian98量子化学程序包, 采用B3LYP密度泛函(DFT)的方法, 在6-31G(d,p)水平上对分子的几何构型进行结构优化; 预测目标产物的振动光谱, 结果表明与实验值相符.     

Density, Excess Volume, and Viscosity of Vinyl Acetate or?Benzyl Acetate with (o-, m-, p-)Xylenes and?Ethylbenzene at T=(303.15 and 313.15) K

Viscosity η, and density ρ, of binary liquid mixtures of vinyl acetate or benzyl acetate with o-xylene, m-xylene, p-xylene and ethyl benzene have been determined at (303.15 and 313.15) K for the entire composition range. From the experimental values excess molar volume and deviations in viscosity have been calculated. These excess quantities were fitted to the Redlich-Kister polynomial equation. The viscosity data have been correlated using the Grunberg-Nissan, Tamura and Kurata, Auslander, and Jouyban-Acree models.     

在离子液体中一步法合成吡唑[5,4-b]-γ-吡喃衍生物

芳醛、丙二腈与4,5-二氢-3-甲基-5-氧代-1-苯基吡唑在离子液体[bmim][BF₄]中反应, 合成了2-氨基-4-芳基-3-氰基-5-甲基-7-苯基吡唑[5,4-b]-γ-吡喃衍生物, 该法快速、高效, 是一种洁净的合成方法. 产物的结构通过红外光谱、核磁共振氢谱和元素分析进行表征.     

水悬浮体系中α,β-环氧酮类化合物的合成研究

在水悬浮体系中使用三氯异氰尿酸/碱氧化体系对α,β-不饱和酮化合物进行环氧化和对烯丙基醇类化合物进行直接氧化-环氧化制备α,β-环氧酮, 考察了表面活性剂、碱等因素对反应的影响. 反应无需有机溶剂, 对于大部分的烯酮和烯丙基醇反应可以在数小时内完成, 产率良好.     

α-糜蛋白酶催化合成β-脲基巴豆酸酯

β-脲基巴豆酸酯是合成6-甲基嘧啶二酮衍生物及3,4-二氢嘧啶二酮衍生物的重要中间体,在生物制药中有着广泛的应用.由于酶具有绿色、安全、高效的催化特性,采用α-糜蛋白酶为生物催化剂,以N,N-二甲基甲酰胺为反应介质,37℃条件下,通过1,3-二羰基化合物和脲的缩合反应,合成了一系列β-脲基巴豆酸酯类化合物.     

咔唑-N，S-杂冠醚类荧光探针的合成及其检测Ag+性质

以双(2?氯乙基)氨基甲酸叔丁酯、2,2?(乙烷?1,2?二丁基(氧基))二乙硫醇和N?乙基咔唑为起始原料,设计、合成了一种含有杂冠醚基团的新型荧光探针分子L,其结构经¹H NMR、¹³C NMR及高分辨质谱进行了表征。随后利用荧光光谱在水/乙醇溶剂(4∶1,V/V)中研究了探针L对Ag⁺的选择性识别。研究结果表明,探针L与Ag⁺以1∶1的比例配位。通过计算得到配位常数K_a为2.01×10⁵ L·mol^-1,检测限为4.13μmol·L^-1。通过实验证明,该探针分子可应用于河流等环境水样中Ag⁺的检测。     

Synthesis and characterization of dinuclear p-, m- and o-xylyl bridged complexes of molybdenum and tungsten. The crystal structures of μ-p-xylyl- bis(η-pentamethyl-cyclopentadienyltri- carbonylmolybdenum) and μ-m-xylyl-bis(η- pentamethylcyclopentadienyltricarbonyltungsten)

The reactions of (M = Mo, W) with α,α′-p-, m- and o-dichloro-xylenes yielded p-, m- and o-xylyl bridged dinuclear complexes of in high yields. All of such new complexes are stable to air and water, even stable in dilute acids and bases.     

11β-羟基-16β-甲基-16α,17α-环丙烷基-孕甾-1,4-二烯-3,20-二酮的合成

由泼尼松龙(Prednisolone)为原料, 经甲磺酰化、甲基化、脱水、两次1,3-偶极反应以及其后的两次热分解共7步反应, 以23.5%的总收率首次制得了11β-羟基-16β-甲基-16α,17α-环丙烷基-孕甾-1,4-二烯-3,20-二酮这一重要的潜在药物及化学中间体. 实验同时发现, 1,3-偶极反应及其之后的热分解反应具有高度的立体选择性和区域选择性. 这种立体选择性和区域选择性通过¹H NMR数据加以了证明.     

Structural studies of 3-chloro-N-(8′-quinolyl)×benzo[b]thiophene-2-carboxamide

3-Chloro-N-(8′-quinolyl)benzo[b]thiophene-2-carboxamide was synthesized from 3-chlorobenzo[b] thiophene -2-carboxyl chloride and 8-aminoquinoline in the presence of triethylamine. The single crystal X-ray structure determination confirmed the earlier proposed structure and also characterized by ¹HNMR, and Mass spectroscopy. Crystallographic study reveals that the structure crystallizes in monoclinic system, a = 14.878(4) ?, b = 8.4292(15) ?, c = 25.461(7) ?, β = 112.022(18)°, Z = 8, V = 2960.20(12) ?³ with space group C2/c (No. 15). In the structure packing, three kinds of interactions are responsible for the stability of the structure. Infinite two-dimensional stair-like layered chains are formed by relatively strong intermolecular hydrogen bonds [C14—H14...O1]. These parallel chains are connected by several π—π and CH—π interactions, alternatively. There are two such parallel chains with 70.53°, which are in contact by van der Waals interactions.     

Rare earth metal-rich indides RE 4IrIn ( RE = Gd–Er), RE 4IrInO0.25 ( RE = Gd, Er), and RE 4 T In1– x Mg x ( RE = Y, Gd; T = Rh, Ir)

The rare earth-transition metal-indides RE ₄IrIn (RE = Gd–Er) and the solid solutions RE ₄ TIn_1–x Mg _x (RE = Y, Gd; T = Rh, Ir) were prepared by arc-melting of the elements and subsequent annealing. The rare earth sesquioxides were used as oxygen source for the suboxides RE ₄IrInO_0.25 (RE = Gd, Er). Single crystals of the indides were grown via slowly cooling of the samples and they were investigated via X-ray powder diffraction and single crystal diffractometer data: Gd₄RhIn type, F 3m, a = 1372.3(6) pm for Gd₄IrIn, a = 1365.3(6) pm for Tb₄IrIn, a = 1356.7(4) pm for Dy₄IrIn, a = 1353.9(4) pm for Ho₄IrIn, a = 1344.1(4) pm for Er₄IrIn, a = 1370.3(5) pm for Y₄RhIn_0.54Mg_0.46, a = 1375.6(5) pm for Gd₄IrIn_0.55Mg_0.45, a = 1373.0(3) pm for Gd₄IrInO_0.25, and a = 1345.1(4) pm for Er₄IrInO_0.25. The rhodium and iridium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ and IrRE ₆ prisms leads to three-dimensional networks which leave voids that are filled by regular In₄ or mixed In_4–x Mg _x tetrahedra. The indium (magnesium) atoms have twelve nearest neighbors (3In(Mg) + 9RE) in icosahedral coordination. The rare earth atoms build up a three-dimensional, adamantane-like network of condensed, edge and face-sharing octahedra. For Gd₄IrInO_0.25 and Er₄IrInO_0.25 the RE1₆ octahedra are filled with oxygen. The crystal chemical peculiarities of these rare earth rich compounds are discussed. Correspondence: Rainer P?ttgen, Institut für Anorganische und Analytische Chemie, Westf?lische Wilhelms-Universit?t Münster, Germany.     

MgCl2/Et3N催化合成α,β-不饱和氰代酯

用MgCl₂/Et₃N催化氰乙酸乙酯和芳香醛的缩合反应合成α,β-不饱和氰代酯, 反应可在室温进行. 产率87%～92%.     

Rare earth metal-rich indides RE 4IrIn ( RE = Gd–Er), RE 4IrInO0.25 ( RE = Gd, Er), and RE 4 T In1– x Mg x ( RE = Y, Gd; T = Rh, Ir)

The rare earth-transition metal-indides RE ₄IrIn (RE = Gd–Er) and the solid solutions RE ₄ TIn_1–x Mg _x (RE = Y, Gd; T = Rh, Ir) were prepared by arc-melting of the elements and subsequent annealing. The rare earth sesquioxides were used as oxygen source for the suboxides RE ₄IrInO_0.25 (RE = Gd, Er). Single crystals of the indides were grown via slowly cooling of the samples and they were investigated via X-ray powder diffraction and single crystal diffractometer data: Gd₄RhIn type, F [`4]\bar 4 3m, a = 1372.3(6) pm for Gd₄IrIn, a = 1365.3(6) pm for Tb₄IrIn, a = 1356.7(4) pm for Dy₄IrIn, a = 1353.9(4) pm for Ho₄IrIn, a = 1344.1(4) pm for Er₄IrIn, a = 1370.3(5) pm for Y₄RhIn_0.54Mg_0.46, a = 1375.6(5) pm for Gd₄IrIn_0.55Mg_0.45, a = 1373.0(3) pm for Gd₄IrInO_0.25, and a = 1345.1(4) pm for Er₄IrInO_0.25. The rhodium and iridium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ and IrRE ₆ prisms leads to three-dimensional networks which leave voids that are filled by regular In₄ or mixed In_4–x Mg _x tetrahedra. The indium (magnesium) atoms have twelve nearest neighbors (3In(Mg) + 9RE) in icosahedral coordination. The rare earth atoms build up a three-dimensional, adamantane-like network of condensed, edge and face-sharing octahedra. For Gd₄IrInO_0.25 and Er₄IrInO_0.25 the RE1₆ octahedra are filled with oxygen. The crystal chemical peculiarities of these rare earth rich compounds are discussed.     

微波辐射相转移催化下水相合成α,α'-双亚苄基环烷酮

芳醛与环戊酮或环己酮在碳酸钠水溶液中, 用微波辐射-相转移催化法合成 α,α'-双亚苄基环烷酮, 反应在0.5～7 min内完成, 产率高达80%～99%, 后处理极为简便, 是一种环境友好的绿色合成.     

Zn/AlCl3促进下二硫醚与α,β-不饱和化合物的共轭加成

二芳基二硫醚与锌粉在DMF 中110 ℃反应, 生成二硫醚与锌的复合物; 后者在无水AlCl₃存在下与丙烯酸酯、丙烯腈反应分别生成β-芳硫基丙酸酯和相应的腈, 产率48%～91%.