A Stereoselective Synthesis of Two 2-Deoxy-3-Phosphasugars Epimeric at Phosphorus

Abstract

A synthetic route to 2-deoxy-3-phosphasugar derivatives utilising a stereoselective addition of a phosphinate to an aldehyde is described.     

Synthesis of the Epimeric Secosteroids Strophasterols A and B

Two epimeric rearranged ergostanes, strophasterols A and B, with an unprecedented carbon skeleton were synthesized from ergosterol, both in 17 steps via a common secosteroidal intermediate. The conversion of ergosterol into the pivotal intermediate involved an efficient acid‐catalyzed double‐bond migration from ring B to ring D, oxidative cleavage of the double bond, and a completely diastereoselective acyl radical cyclization to form an isolated cyclopentanone ring unique to this recently discovered family of steroidal compounds produced by mushrooms. The intermediate was transformed stereodivergently into two epimeric cyclopentane derivatives through hydrogenation using two types of catalysts. One epimer was elaborated into strophasterol B by utilizing peracid oxidation of an iodide to provide an epoxide directly, and the other epimer was elaborated into strophasterol A, which is known to be a suppressor of endoplasmic reticulum stress.     

Two Novel Epimeric Eremophilane Sesquiterpenes from the Flower of Cacalia tangutica

Two novel epimeric eremophilane sesquiterpenes, 7β-H-3α-angeloyl-9(10)-ene-11,12-epoxy-8-oxoeremophilane (1) and 7β-H-3α-angeloyl-9(10)-ene-11, 12-epoxy-8-oxoeremophilane (2) were isolated from the methanol extract of the flower of Cacalia tangutica (Franch.) Hand-Mazz. Their structures were characterized by 1D-, 2D-NMR (^1H-^1H COSY, HMQC, HMBC, ^1H-^1H NOESY) and HRESI-MS techniques.     

两个新颖的联环十二烷衍生物的合成及结构表征

2-（2＇-Oxo-3＇-oximidocyclododecyl） cyclododecanone （1） and 2-（1＇-hydroxylcyclododecyl） cyclododecanone （2） were synthesized and characterized. The conformation analysis was carried out based on the NMR, molecular mechanics calculation and X-ray diffraction. The conformation of two cyclododecyl moieties of both 1 and 2 was found to be the [3333]-2-one or [3333] square conformation both in the crystal state and the solution. The dihedral angle between carbonyl and the oxime double bond of the ring B is 180°in the crystal of 1. The protons or hydroxyl group of carbon atoms to link the two cyclododecyl moieties of 1 and 2 constitute dihedral angles of 174°in the crystal, and 175°in the solution, and the C-C 6 bond between two cyclododecyl moieties can not freely rotate in the solid state and the solution. In addition, compound 2 was the first example of a-comer-anti-monosubstituted cyclododecanone. synthesis     

两种有机-无机复合杂多化合物的水热合成及结构表征

利用水热法制备了基于饱和Keggin结构阴离子构筑的有机-无机复合多金属氧酸盐(4,4′-bipy)4H4[PMo12O40](CH3COO).1.5H2O(1)和(4,4′-Hbipy)2(4,4′-bipy)2H[PW12O40].3.5H2O(2)(4,4′-bipy=4,4′-联吡啶),并借助元素分析、红外光谱、紫外光谱、热分析和X射线单晶衍射分析了两种化合物的组成和结构.结果表明,化合物1和2均属于单斜晶系,P2(1)/c空间群.化合物的晶胞参数为:a=1.869 40(13)nm,b=1.404 23(9)nm,c=2.707 76(18)nm,β=105.848 0(10)°,V=6.837 9(8)nm3,Z=4,R1=0.095 4;化合物2的晶胞参数为:a=1.884 80(12)nm,b=1.409 89(9)nm,c=2.664 92(17)nm,β=105.368 0(10)°,V=6.828 4(8)nm3,Z=2,R1=0.097 2.两种化合物结构类似,其结构单元均是由饱和Keggin阴离子与游离的4,4′-联吡啶分子通过静电作用相结合形成的.     

Synthesis and Structural Chemistry of Two Novel Transition Metal Organic Phosphonates

Two novel transition metal phosphonate compounds, [Co（H2BDPP）（phen）]n 1 （BDPP = p-O3PCH2（C6H4）CH2PO3, phen = 1,10-phenanthroline） and [Pb3（BCP）2]n 2 （BCP = OOC（C6H4）CH2PO3）, have been synthesized and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallizes in the monoclinic system, space group C2/c with a = 21.169（4）, b = 12.001（2）, c = 7.6211（15）A, β = 98.03（3）°, V= 1917.2（6）A^3, C20H18N2O6P2Co, Mr = 505.22, Z = 8, De= 1.737 g/cm^3, p = 1.107 mm^-1, F（000） = 1020, the final R= 0.0450 and wR = 0.1306 for 2072 observed reflections （I 〉 2σ（I）. Compound 2 crystallizes in the monoclinic system, space group C2/c with a = 4.7167（9）, b = 18.753（2）, c = 22.781（3）A, β = 91.07（3）°, V= 2014.7（14）A^, C8H6O5PPb1.5, Mr = 523.88, Z = 8, Dc = 3.454 g/cm^3, p = 25.222 mm^-1, F（000） = 1856, the final R = 0.0441 and wR = 0.1906 for 2259 observed reflections （I 〉 2σ（I）. In compound 1, the 1D chain running along the c axis is bridged by four ligands （trans- HO3PCH2C6H4CH2PO3H） in four different directions to extend the structure into a three- dimensional network. In compound 2, the Pb（II） displays 4- and 5-coordination modes. There is a one-dimensional P-O-Pb band along the a axis formed by PO3 groups and Pb（II） cations. These bands are joined by μ2-O of -COO to yield two-dimensional inorganic P-O-Pb layers which are pillared by the OOCC6HaCH2PO3 ligands to form a three-dimensional network. Moreover, compound 2 displays a strong emission band attributed to the ligand-centered （LC） transition.     

Synthesis and Structural Characterisation of Two Novel Diastereoisomeric Naproxen Appended β-Cyclodextrin Derivatives

The condensation reaction of 6-deoxy-6-amino(2-aminoethyl)-cyclomaltoheptaose (β-CyDen) and racemic [(R, S)-2-(6-methoxy-2-naphthyl) propanoic acid] (R,S-naproxen) affords two new diastereoisomeric naproxen-appended β-cyclodextrin derivatives. The structural analysis of these two β-CyD derivatives, undertaken by combined use of circular dichroism (CD) and 1D or 2D NMR techniques, shows that the naphthalene ring of the naproxen is included in the CyD cavity in both derivatives. The CD spectra are consistent with an axial complexation model, moreover, the self-inclusion mode is further corroborated by ¹H NMR ROESY spectra which also suggest the orientation of the naphthyl moiety in the cavity of both the diastereoisomers.     

Solvothermal Synthesis, Structural Characterization and Properties of Two New Layered Lanthanide Sulfates

Two new layered lanthanide sulfates,[C₁₀H₁₀N₂][Pr₂(SO₄)₄(H₂O)₂](1)and[H₅O₂][Sm(SO₄)₂(H₂O)₃](2)were synthesized via solvothermal reaction and structurally characterized by single-crystal X-ray diffraction(XRD), infrared(IR) spectroscopy, thermal analysis, fluorescent spectra and inductively coupled plasma(ICP). Crystal data for compound 1, triclinic, P space group, a=0.8052(4) nm, b=0.9438(4) nm, c=1.4990(7) nm, α=79.450(5)°, β= 83.703(5)°, γ=74.048(5)°, V=1.0746(9) nm³, Z=2; for compound 2, monoclinic, P2₁/c space group, a=0.6599(11) nm, b=1.8940(3) nm, c=0.8765(14) nm, β=96.596(2)°, V=1.0883(3) nm³, Z=4. Structure analysis indicates that both the compounds exhibit a 2D corrugated layer structure, with protonated 4,4'-bipyridine cations and water dimmers (H₅O₂)⁺ located between the inorganic layers of compounds 1 and 2, respectively. Luminescent properties of compounds 1 and 2 were further investigated.     

Synthesis of the Four Epimeric Tosylates of (5R)-2, 3-Epoxy-5-isopropenyl-cyclohexanol

Described is the synthesis of the four optically pure epoxy-tosylates 5, 6, 9 and 12, each with four chiral centers determined, from a single starting material, (R)(-) carvone.     

两种含有十二元环的层状稀土硫酸盐的合成、结构表征及性质研究

通过溶剂热合成技术,我们得到了两种新的二维层状稀土硫酸盐:[Tb₂(SO₄)₅][(CH₃)₂NH₂]₄(1)和[Y₂(SO₄)₅][(CH₃)₂NH₂]₄(2),并通过X-射线衍射、元素分析及红外、热重对化合物进行了表征。两种化合物都属于三斜晶系,P1空间群。其中化合物1:a=0.9887(3)nm,b=1.1061(3)nm,c=1.5354(4)nm,α=70.45(0)°,β=75.12(0)°,γ=67.11(0)°,Z=2;化合物2:a=0.9816(5)nm,b=1.1001(5)nm,c=1.5286(8)nm,α=70.44(1)°,β=75.45(1)°,γ=67.48(1)°,Z=2。通过对晶体结构进行表征我们发现两种化合物都含有二维层状无机骨架结构,该层由2种不同类型的双链和十二元环构成。我们还对化合物1的荧光性质进行了研究,其在369nm的激发波长下表现出了Tb³⁺ 的特征发射。     

Synthesis,Structural Characterization and Properties of Two Strontium Borates Constructed from Oxo Boron Clusters

Two strontium borates Sr₂[B₆O₉(OH)₄] (1) and Sr₂B₅O₉(OH)·H₂O (2), with acentric structures have been synthesized under hydro/solvothermal conditions. Compound 1 is reported for the first time in the strontium borates system, and it crystallizes in the monoclinic space group P2₁ with unit cell parameters a = 6.8445(5) Å, b = 8.7033(6) Å, c = 8.4632(6) Å, β = 100.581(6)°, V = 495.58(6) ų and Z = 2. Its structure consists of unusual borate layers of 3, 11-membered rings, which are interconnected via Sr–O ionic bonds and hydrogen bonds to generate a 3D supramolecular network. Compound 2 is a known strontium borate, crystallizing in the monoclinic space group C ₂ with a = 10.161 (13) Å, b = 7.965(4) Å, c = 6.393(11) Å, β = 128.0(2)°, V = 407.7(14) ų and Z = 2. Second-harmonic generation measurements on the powder samples reveal that 1 and 2 exhibits good SHG efficiency about 1.5 and 2 times that of KDP (KH₂PO₄) powder respectively.     

Zopfiellasins A–D,Two Pairs of Epimeric Cytochalasins from Kiwi-Associated Fungus Zopfiella sp. and Their Antibacterial Assessment

In our continuous search for antibacterial agents against Pseudomonas syringae pv. actinidiae (Psa) from kiwi-associated fungi, two pairs of epimeric cytochalasins, zopfiellasins A–D (1–4), were characterized from the fungus Zopfiella sp. The structures were established on the basis of spectroscopic data analysis, while the absolute configurations were determined by single-crystal X-ray diffraction. Compounds 1 and 3 exhibited antibacterial activity against Psa with MIC values of 25 and 50 μg/mL, respectively. This is the first report of anti-Psa activity of cytochalasin derivatives.     

Total Synthesis and Biological Evaluation of the Antibiotic Lysocin E and Its Enantiomeric,Epimeric, and N‐Demethylated Analogues

Lysocin E, a macrocyclic peptide, exhibits potent antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA) through a novel mechanism. The first total synthesis of lysocin E was achieved by applying a full solid‐phase strategy. The developed approach also provides rapid access to the enantiomeric, epimeric, and N‐demethylated analogues of lysocin E. Significantly, the antibacterial activity of the unnatural enantiomer was comparable to that of the natural isomer, suggesting the absence of chiral recognition in its mode of action.     

Total Synthesis and Biological Evaluation of the Antibiotic Lysocin E and Its Enantiomeric,Epimeric, and N‐Demethylated Analogues

Lysocin E, a macrocyclic peptide, exhibits potent antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA) through a novel mechanism. The first total synthesis of lysocin E was achieved by applying a full solid‐phase strategy. The developed approach also provides rapid access to the enantiomeric, epimeric, and N‐demethylated analogues of lysocin E. Significantly, the antibacterial activity of the unnatural enantiomer was comparable to that of the natural isomer, suggesting the absence of chiral recognition in its mode of action.     

Synthesis, Structural Features and Evaluation of Antibacterial Activities of Two Schiff Bases Derived from 3,4-Dihydroxybenzhydrazide

A new Schiff base compound (I), (E)-N'-(2-hydroxy-3-methoxybenzylidene)-3,4-dihydroxybenzohydrazide-ethanol-water (1/1/1), has been synthesized and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 7.459(4), b = 18.316(10), c = 13.638(7), β = 101.585(9)o, V = 1825.2(17)3, Z = 4, μ = 0.104 mm-1, Dc = 1.333 g/cm3, F(000) = 776, the final R = 0.0635 and wR = 0.1302 for 3216 observed reflections with I 2σ(I). Another compound (Ⅱ), (E)-N'-(2,5-dimethoxybenzylidene)-3,4-dihydroxybenzohydrazide-ethanol-water (1/1/1), has been synthesized and reported before. The antibacterial activities of these two compounds against seven bacteria were first evaluated, and one compound showed considerable antibacterial activity against S. aureus.     

两种具有三维孔道结构有机模板稀土硫酸盐的合成、表征及性质研究

本文分别采用水热和溶剂热的方法,以乙二胺和哌嗪为有机模板剂分别合成了两种新的三维孔道结构的稀土硫酸盐[Gd2(SO4)5(H2O)2][C2N2H10]2(1),[Eu2(SO4)5(H2O)2][C4N2H12]2(2),并且通过单晶X射线衍射、元素分析、红外、热重对两种化合物进行了表征。化合物1和2都属于单斜晶系,P21/c空间群。化合物1:a=0.652 1(4)nm,b=1.692 0(9)nm,c=2.023 3(11)nm,β=95.168(7)°,Z=4。化合物2:a=1.972 1(2)nm,b=1.927 1(2)nm,c=1.323 20(14)nm,β=92.307 0(10)°,Z=8。单晶结构分析表明,这两种化合物的无机骨架都是由SO4连接具有交替十六元环与八元环二维层形成的三维孔道结构。化合物2的固体荧光分析表明,在396 nm的激发波长下表现出Eu3+的特有发光性质。