Synthesis of Morpholine-Based Analogues of (−)-Zampanolide and Their Biological Activity

We describe the convergent synthesis of three prototypical examples of a new class of analogues of the complex, cytotoxic marine macrolide (−)-zampanolide that incorporate an embedded N-substituted morpholine moiety in place of the natural tetrahydropyran ring. The final construction of the macrolactone core was based on a high-yielding intramolecular HWE olefination, while the hemiaminal-linked side chain was elaborated through a stereoselective, BINAL-H-mediated addition of (Z,E)-sorbamide to a macrocyclic aldehyde precursor. The synthesis of the common functionalized morpholine building block involved two consecutive epoxide openings with tosylamide and the product of the first opening reaction, respectively, as nucleophiles. Of the three morpholino-zampanolides investigated, the N-acetyl and the N-benzoyl derivatives both exhibited nanomolar antiproliferative activity, thus being essentially equipotent with the natural product. In contrast, the activity of the N-tosyl derivative was significantly reduced.     

Synthesis of Tetracycline Analogues and Test of Their Affinity of Synthetic Hydroxyapatite

Eight of new 5-oxo[1] benzopyrano [2,3-b] pyridines as the analogues of tetracycline, were designed and synthesized, and their affinity to the hydroxyapatite-the inorganic composition of bone were tested.     

Synthesis of Tetracycline Analogues and Test of Their Affinity on Synthetic Hydroxyapatite

To develop bone target drugs is an attractive field for increasing the potency and selectivity of these drugs in the treatment of osteoporosis and Pagets disease etc. As known, after systematic administration tetracycline can be distributed in bone and bind to hydroxyapatite with high affinity1. Thus we tried to use tetracycline as a bone targeted carrier. However, tetracycline is less stable, and its complex structure bring much difficulty in the coupling reaction and purification of the p…     

An Economical Synthesis of Lewis X,Sialyl Lewis X and Their α-Galactosyl Analogues

Abstract

Economical syntheses of the Lewis X trisaccharide 8 and sialyl Lewis X tetrasaccharide 18 epitopes and the syntheses of the α-galactosyl epimers 9 and 20 of these structures are described. Thioglycosides 2, 5, 11 and 15 were used as glycosyl donors to construct the desired compounds in a stepwise manner in dimethyl(methylthio)sulphonium triflate promoted couplings. Benzyl 3-O-(2,3,4-tri-O-benzyl-α-L-fucopyranosyl)-2-acetamido-6-O-benzyl-2-deoxy-α-D-glucopyranoside (4) was a key structure in these syntheses, and was synthesised in multi-gram scale.     

Synthesis and Antitumor Activity of Tanshinone Analogues

8, 8-Dimethyl-5, 6, 7,8-tetrahydrophenanthrene-3, 4-dione (3) and 8, 8-dimethyl-2- ( 1-hydroxy ethyl) -5,6, 7, 8-tetrahydrophenanthrene-3,4-dione (4), two analogues of the antitumor active tanshinone, were synthesized from anisole. The synthesized compounds 3 and 4 were shown to be highly active against leukemia P-388 cell fine as assayed by in vitro MTT method.     

Synthesis and Antioxidant Activity of Sapriparaquinone Analogues

It has been considered that the lipid peroxidition damage was involved in aging and pathological disorders. Some phases of atherosclerosis, neuronal ceroid lipofuscinosis, intermittent claudication, oxygen toxicity, and liver injury caused by orotic acid, ethanol, phosphorous or chlorinated hydrocarbons have been discussed in relation to lipid peroxidion1-3. We found that a series of unique 4,5-secoditerpenoidal compounds isolated from the medicinal plant Salvia prionitis showed various bioact…     

Mononuclear and Dinuclear Yttrium Complexes Supported by Pyrrolide Ligands: Syntheses,Structures and Catalytic Behaviors towards the Ring-opening Polymerization of ε-Caprolactone

The syntheses, structures and catalytic activities of two yttrium complexes supported by pyrrolide ligands are reported. Treatment of Y(N(Si Me3)2)3 with one equivalent of H3bptd(H3bptd = 1,9-bis(2-pyrrolyl)-2,5,8-triazanona-1,8-diene) in THF gave a complex of composition [Y(bptd)(THF)]2(1). Reaction of Y(N(Si Me3)2)3 with one equivalent of H3tpa(H3tpa = tris(pyrrolyl-?-methyl)amine) in THF generated [Y(tpa)(THF)3](2) in good yield. Complexes 1and 2 have been characterized by single-crystal X-ray diffraction, elemental analyses and NMR spectroscopy. Complex 1 is dinuclear. The two metal centers are doubly bridged by two amine nitrogen atoms to form a Y–N–Y–N four-membered rhombus ring. The geometries of Y3+ ions in 1and 2 are well described as pentagonal bipyramid and capped octahedron, respectively. The ring-opening polymerization reactions of ?-caprolactone initiated by 1 and 2, respectively, were investigated. They both exhibited good catalytic activity for the polymerization of ?-caprolactone. All of the obtained polymers have high molecular weights and relatively narrower PDIs. The polymers generated by 2 possessed polydispersity close to 1.1. The good catalytic activities of 1 and 2 reveal their potential applications in polymer industry.     

Mononuclear and Dinuclear Copper Complexes of Tridentate Redox-active Ligands with Tunable H-bonding Donors: Structure,Spectroscopy and H+/e− Reactivity

In this research article, we describe the synthesis and characterization of mononuclear and dinuclear Cu complexes bound by a family of tridentate redox-active ligands with tunable H-bonding donors. The mononuclear Cu-anion complexes were oxidized to the corresponding “high-valent” intermediates by oxidation of the redox-active ligand. These species were capable of oxidizing phenols with weak O−H bonds via H-atom abstraction. Thermodynamic analysis of the H-atom abstractions, which included reduction potential measurements, pK_a determination and kinetic studies, revealed that modification of the anion coordinated to the Cu and changes in the H-bonding donor did not lead to major differences in the reactivity of the “high-valent” CuY complexes (Y: hydroxide, phenolate and acetate), which indicated that the tridentate ligand scaffold acts as the H⁺ and e⁻ acceptor.     

Synthesis and Antioxidant Properties of Novel Silybin Analogues

Eight novel silybin analogues (7a-h) were synthesized and their antioxidant properties including the capability of scavenging superoxide anion free radicals and the inhibitory effect on DPPH free radicals were determined. Several synthetic compounds showed comparable antioxidative effect to that of quercetin.     

Synthesis and Biological Evaluation of Pyranone Analogues of Territrem B

As a highly selective and potent acetylcholinesterase(AChE)inhibitor,territrem B wasisolated by Ling et al.from a strain of Aspergillus terreus in19791,2.Zhao et alreported mimic preparation of territrem B analogues from triterpenoids and found thatthe enone moiety and aromatic ring played important roles in their syntheticcompounds3,4.To further detect essential pharmacophors for AChE inhibitors,wesimplified the A/B ring system of territrem B and synthesized a number of pyranonepharmacop…     

Synthesis and Structure of a New Dinuclear Uranyl Complex

Dinuclear complexes have been widely investigated since 1970s when Robson proposed the conception of dinucleating ligand1,2. These compounds attracted much interests because of their applications as metal-enzemy model in bioinorganic chemistry or promising applications as functional materials. Most of these dinuclear complexes contain d transition metals as central ions. Few dinuclear U complexes have been reported. It is known, in most complexes of axial ion, five donors from ligands shou…     

Synthesis of ( ) 8-O-Cinnamyl-p-chlorogoniotriol and its Analogues

HowiinolAI',anovellactoneisolatedfromtheethanolicextractsoftherootandsternbarkofGoniolhanlush()TI)iiMerr.(Annoaceae)inourlaboratory.hasbeenshowntopossesssignificantantitullloractivitiestowardhumantumor117vilroandI,71'if'oandfoxytoxlcit}.Recently.wehavesynthesized1anditsderivativeswitllditTerentestergroupsstartingfromcommerciallyavailablea-D-glucoheptonic-y-lactone.Inordertotindtheirrelationshipofstructureandactivityandtosearchfordrugswithmorepotentantitumoractivity.wehavesynthesized( )8-O-…     

Synthesis and Crystal Structure of a New Mononuclear Copper Complex

<正>A new kind of Cu (II) complex [Cu(tpmb)2Cl2]·CH3OH·H2O (tpmb = 1,3,5-tri(2-pyrimidinyl)sulfanylmethyl-2,4,6-trimethylbenzene) was synthesized, and its structure has been determined by X-ray single-crystal diffraction. It crystallizes in the triclinic, space group P 1 with a = 8.8397(2), b = 13.327(3), c = 13.926(3) A, α = 63.27(3), β = 86.96(3), r = 80.68(3)°, V = 1445.6(5) A3, C49H51Cl2CuN12O2S6, Mr= 1166.82,Z=1, F(000) = 604, Dc = 1.340 g/cm3, μ = 0.735 mm-1, R = 0.0545 and wR = 0.1575 for 4521 observed reflections (I > 2σ(I)). X-ray analysis reveals that the Cu (II) ion is coordinated by two Cl- anions and two nitrogen atoms from different pyrimidine groups, forming a square structure.     

Mononuclear Carbonyl Anion Complexes of Groups Ⅳ and Ⅴ Metals

The anionic carbonyl complexes of groups IV and V metals TM(CO)\begin{document}$ _{6,7} $\end{document} (TM=Ti, Zr, Hf, V, Nb, Ta) are prepared in the gas phase using a laser vaporation-supersonic expansion ion source. The infrared spectra of TM(CO)\begin{document}$ _{6,7} $\end{document}\begin{document}$ ^- $\end{document} anion complexes in the carbonyl stretching frequency region are measured by mass-selected infrared photodissociation spectroscopy. The six-coordinated TM(CO)\begin{document}$ _6 $\end{document}\begin{document}$ ^- $\end{document} anions are determined to be the coordination saturate complexes for both the group IV and group V metals. The TM(CO)\begin{document}$ _6 $\end{document}\begin{document}$ ^- $\end{document} complexes of group IV metals (TM=Ti, Zr, Hf) are 17-electron complexes having a \begin{document}$ ^2 $\end{document}A\begin{document}$ _{\rm{1g}} $\end{document} ground state with \begin{document}$ D_{\rm{3d}} $\end{document} symmetry, while the TM(CO)\begin{document}$ _6 $\end{document}\begin{document}$ ^- $\end{document} complexes of group V metals (TM=V, Nb, Ta) are 18-electron species with a closed-shell singlet ground state possessing \begin{document}$ O_{\rm{h}} $\end{document} symmetry. The energy decomposition analyses indicate that the metal-CO covalent bonding is dominated by TM\begin{document}$ ^- $\end{document}(d)\begin{document}$ \rightarrow $\end{document}(CO)\begin{document}$ _6 $\end{document} \begin{document}$ \pi $\end{document}-backdonation and TM\begin{document}$ ^- $\end{document}(d)\begin{document}$ \leftarrow $\end{document}(CO)\begin{document}$ _6 $\end{document} \begin{document}$ \sigma $\end{document}-donation interactions.     

Synthesis and Characterization of the Tetrazole Analogues of α-Amino Acids

Tetrazoles have found wide applications in coordination chemistry, medicinal chemistry and material science. Especially, when the tetrazole moiety is served as a surrogate for terminal carboxylic acid residues, the peptides have been presented some pharma…     

A 1010 Rate Enhancement of Phosphodiester Hydrolysis by a Dinuclear Aminopeptidase—Transition-State Analogues as Substrates?

Streptomyces dizinc aminopeptidase (sAP) shows a specific activity of 33.7 nmol min⁻¹ mg⁻¹ toward the hydrolysis of the transition-state analogue bis-p-nitrophenylphosphate with a rate constant of k_cat/K_m=100 M ⁻¹ s⁻¹ and a first-order rate enhancement of about 10¹⁰, which is much superior to several Zn chemical models and comparable to some phosphodiesterases. This study suggests that sAP can serve as a novel dinuclear model system to provide further insight into dinuclear hydrolysis.     

A New and Efficient Synthetic Method and Antibacterial Activities of Oxazolidinone Analogues

A series of novel oxazolidinone analogues were prepared by a new and efficient synthetic method and their antibacterial activities were determined. These compounds wer echaracterized by LC-MS and ^1H NMR.     

Solvent‐Free Synthesis of Arylamides and Arylimides,Analogues of Acetylcholine

Abstract

Several arylamides and arylimides, novel inhibitors of acetylcholinesterase, were obtained under solventless conditions; the target molecules were produced with a good overall yield and short reaction times.     

Total Synthesis of (±) Euphraticol and Its Analogues

Total syntheses of racemic Euphraticol and its analogues are described, they constitute anew and efficient synthetic route to abietane diterpenoids. The key steps are alkylation of lithium eno-late of 8 with iodides in the presence of HMPA.     

Facile Synthesis of Ophipogonin C′ and its Three Analogues

Among the huge number of glycoconjuates, the steroidal glycosides are often found as the major components in traditional Chinese medicine. Steroidal glycosides constitute a structurally and biologically diverse class of molecules which have been isolated from a wide variety of both plant and animal species 1. Because of the variety of promising pharmaceutical properties2, the large family of steroidal glycosides has received considerable attention of chemist. Figure 1 OOOOR4R3OR2OOR1O …