Terpendole E,a Kinesin Eg5 Inhibitor,Is a Key Biosynthetic Intermediate of Indole-Diterpenes in the Producing Fungus Chaunopycnis alba

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Highlights? The terpendole biosynthetic gene cluster was isolated ? Terpendole E is a key biosynthetic intermediate of indole-diterpenes ? Terpendole E was overproduced by gene knockout of the bispecific enzyme TerP ? Indole-diterpene biosynthetic pathways can be classified into two groups     

A Convenient,Room‐Temperature–Organic Base Protocol for Preparing Chiral 3‐(Enoyl)‐1,3‐oxazolidin‐2‐ones

In this study, we developed a new protocol for the preparation of the chiral 3‐[(E)‐enoyl]‐1,3‐oxazolidin‐2‐ones under the ultimately simple reaction conditions starting with the corresponding enoyl chlorides and 1,3‐oxazolidin‐2‐ones with Et₃N/LiCl at room temperature. The method generally allows efficient preparation of various derivatives regardless of the steric and electronic nature of the substituents on both the enoyl or the oxazolidinone sites. Excellent yields, combined with the simplicity of the experimental procedures, render the present method immediately useful for preparing the target compounds.     

Quantum tunneling of magnetization via well-defined Dy–Cu exchange coupling in a ferrimagnetic high-spin [Dy4Cu] single-molecule magnet

A centrosymmetric rectangular complex [Dy₄Cu] was prepared from dysprosium(III) 1,1,1,5,5,5-hexafluoropentane-2,4-dionate and copper(II) dimethylglyoximate. From magnetic studies, the Dy magnetic moments are all aligned parallel at the ground state via antiferromagnetic superexchange interaction with the central Cu spin. In pulsed-field magnetization measurements at 0.5 K, complex [Dy₄Cu] exhibited magnetization steps with hysteresis, which is typical of a single-molecule magnet. This behavior is explained in terms of a simple Ising model together with well-defined Dy–Cu exchange coupling (−0.64 K).     

The first A2B2-heterometal ferrimagnetic chain. Structures and magnetic properties of polymeric [Gd2Cu2]n and the corresponding monomer

One-dimensional polymeric complexes consisting of alternating dicopper(II) and digadolinium(III) units exhibited ferrimagnetic behavior which was ascribable to antiferromagnetic coupling across the oximate N-O bridges between the high-spin homodinuclear units.     

Total synthesis of murisolins and evaluation of tumor-growth inhibitory activity

Convergent total syntheses of murisolin (1), natural 16,19-cis-murisolin 2, and unnatural 16,19-cis-murisolin 3 were accomplished by asymmetric alkynylation of alpha-tetrahydrofuranic aldehyde with a diyne and Sonogashira coupling with a gamma-lactone segment as the key steps. Stereoisomers of alpha-tetrahydrofuranic aldehyde were synthesized with high optical purity and the asymmetric alkynylation of these with 1,6-heptadiyne proceeded in good yield and with high diastereoselectivity. The cell-growth inhibition profile and COMPARE analysis of the synthetic compounds 1-3 were also investigated.     

Regio- and stereoselective reactions of gem-difluorinated vinyloxiranes with heteronucleophiles

[Reaction: see text]. Regio- and stereoselectivity in reactions of gem-difluorinated vinyloxiranes with heteronucleophiles were successfully controlled. Halogen atoms were introduced regioselectively at the allylic epoxide carbon with an inversion in stereochemistry using MgBr2*Et2O or Li2CuCl4 to produce anti-vic-halohydrine. The other diastereomers were obtained selectively using LiBr/AcOH or BCl3, and SN2' type products were formed selectively with excellent E preference by changing the reaction temperature. Moreover, a further investigation led us to find that a regio- and stereoselective SN2' addition of several Brnsted acids was dependent on the pKa values of the acids. Under strong acidic conditions, we exclusively obtained E allylic alcohols.     

Phase equilibrium in the system Y-Fe-O at 1100°C

Phase equilibrium was established in the Y-Fe-O system at 1100°C by varying the oxygen partial pressure from −log(P_O2/atm)=15.00 to 0, allowing construction of a phase diagram at 1100°C for the system Y₂O₃-Fe-Fe₂O₃. In the system, two ternary compounds, YFeO₃ and Y₃Fe₅O₁₂, were stable and had nonstoichiometric composition, whereas YFe₂O₄ was not found to be stable. The present result was different from that of previous studies at 1200°C, in which YFe₂O₄ was stable, along with the above two ternary compounds. Lattice constants of YFeO₃ and Y₃Fe₅O₁₂, prepared in air by a quenching method, were determined and compared with previous values, and showed close agreement. The standard Gibbs energy changes of the reactions in the Fe-O system, Fe+1/2O₂=FeO, 3FeO+1/2O₂=Fe₃O₄, and 2/3Fe₃O₄+1/6O₂=Fe₂O₃, were determined, and the obtained values were compared with the previous values. The standard Gibbs energy changes of the reactions, Fe+1/2Y₂O₃+3/4O₂=YFeO₃, and 3YFeO₃+2/3Fe₃O₄+1/6O₂=Y₃Fe₅O₁₂, were calculated from the oxygen partial pressures in equilibrium.     

Anticoagulant action of vanadate.

Sodium orthovanadate (vanadate) prolonged the clotting time of normal human plasma in a dose-dependent manner. The prolongation of clotting time by vanadate linearly decreased with an increase in the concentration of amiloride. Vanadate also was completely additive to prolongation by heparin. When factor Xa or thrombin was incubated with vanadate, the amidolytic activity of each decreased in a dose-dependent manner with vanadate. Amiloride protected the decrease of amidolytic activity of both factor Xa and thrombin by vanadate. The amidolytic activity of trypsin also was inhibited by vanadate, but that of alpha-chymotrypsin was not inhibited, suggesting that vanadate preferentially inhibits the amidolytic activity of trypsin and trypsin-like enzymes. These results show that vanadate prolongs the clotting time of plasma through mechanisms involving in part the inhibition of the activity of both factor Xa and thrombin.