Makoto Yamashita

Two neuraminidase (NA) inhibitors, zanamivir (Relenza) and oseltamivir phosphate (Tamiflu), have been licensed for the treatment of and prophylaxis against influenza. In this paper, the new potent NA inhibitor R-125489 is reported for the first time. R-125489 inhibited the NA activities of various type A and B influenza viruses, including subtypes N1 to N9 and oseltamivir-resistant viruses. The survival effect of R-125489 was shown to be similar to that of zanamivir when administered intranasall

The reaction of boryllithium 2 with 1.0 or 0.5 equiv of MgBr2·OEt2 provided boryl Grignard reagents, borylmagnesium bromides 3 and 4, or bis(boryl)magnesium 5. Structures of 3, 4, and 5 in the crystals and solutions indicated the ionic character of the B−Mg bonds. The reactivity of borylmagnesium 3 with benzaldehyde was different from that of boryllithium 2. Benzoylborane 7 was fully characterized as the first acylborane.

Pentacoordinate and tetracoordinate carbon and boron compounds (27, 38, 50-52, 56-61) bearing an anthracene skeleton with two oxygen or nitrogen atoms at the 1,8-positions were synthesized by the use of four newly synthesized tridentate ligand precursors. Several carbon and boron compounds were characterized by X-ray crystallographic analysis, showing that compounds 27, 56-59 bearing an oxygen-donating anthracene skeleton had a trigonal bipyramidal (TBP) pentacoordinate structure with relatively

Four three-coordinate arylpalladium amido complexes with a single hindered phosphine were isolated and structurally characterized. Each possessed a T-shaped geometry. Several of these complexes possessed true three-coordinate structures that lacked any additional coordination by ligand C-H bonds. All of the three-coordinate complexes underwent reductive elimination to form the corresponding triarylamine. A comparison of the rate of reaction of the three-coordinate compounds demonstrated that the

Two neuraminidase (NA) inhibitors, zanamivir (Relenza) and oseltamivir phosphate (Tamiflu), have been licensed for use for the treatment and prophylaxis of influenza. We have reported on laninamivir (code name, R-125489), a novel neuraminidase inhibitor, and have discovered that the laninamivir prodrug CS-8958 worked as a long-acting neuraminidase inhibitor in a mouse influenza virus infection model when it is intranasally administered. In this study, CS-8958 was administered just once 7 days be

A key reactive species, lithium borylcyanocuprate, was isolated and fully characterized in a one-pot carboboration of alkynes. The carboboration involves a boryllithium, CuCN⋅2 LiCl, an ester-substituted alkyne, and an organic electrophile (see scheme). By changing the reaction temperature, the syn/anti ratio of the carboborated products can also be changed.

A little help from my friends: a highly reactive, 16-electron square-planar rhodium complex was isolated. This species displays an intermolecular interaction between the rhodium and the C-H bond of another molecule as the fourth ligand to form an infinite network in the crystal lattice. The complex undergoes oxidative addition to the O-H bond of phenol or a primary alkyl alcohol to give the corresponding hydrido-phenoxido Rh(III) complex or carbonyl Rh(I) complex, respectively.

Crystals of the two-coordinate palladium(0) complex 1 bearing the new N-heterocyclic carbene ligand, ITmt, directly and rapidly fixed both O2 and CO2 from air to produce the corresponding palladium(II) peroxocarbonate complex 2. The present reaction consists of dioxygenation of the palladium(0) complex 1 to the palladium(II) peroxo complex 3 and the subsequent CO2 insertion to produce the peroxocarbonate complex 2. Reaction of the crystals of 1 with air was monitored by microscopic IR spectrosco

Oseltamivir and zanamivir are currently licensed worldwide for influenza treatment and chemoprophylaxis. Both drugs require twice-daily administration for 5 days for treatment. A new influenza drug, laninamivir (code name R-125489), and its prodrug form, CS-8958 (laninamivir octanoate or laninamivir prodrug), which are long-acting neuraminidase inhibitors, are introduced in this review. Laninamivir potently inhibited the neuraminidase activities of various influenza A and B viruses, including su

Several new bulky monophosphine-ligated methylpalladium complexes were synthesized. Treatment of Pd(cod)MeCl (cod = cyclooctadiene) with bulky phosphines, PtBu3, or P(o-tol)3 afforded monophosphine-ligated methylpalladium chloride complexes 1a and 1b, which were isolated as crystalline solids in excellent yields. The structures depended on the shape of the ligand: a mononuclear three-coordinate structure for 1a and a chloride-bridged dinuclear structure for 1b. Absorption of chloride from methyl

Abstract This account reviews the chemistry of “boryl anion.” Boryl anions can be classified with their metallic counterpart, such as Li, Mg, Cu, and Zn in a similar manner to the classification of carbanions. The early attempts to generate boryl anions by reductive dehalogenation of haloboranes with alkali metal or photolysis of tetraphenylborate compounds had no modern spectroscopic identification of the reactive “boryl anion.” Recent developments of base-stabilized boryl anion, base–BH2−M+ (b

To determine the trans effect on the rates of reductive eliminations from arylpalladium(II) amido complexes, the reactions of arylpalladium amido complexes bearing symmetrical and unsymmetrical DPPF (DPPF = bis(diphenylphosphino)ferrocene) derivatives were studied. THF solutions of LPd(Ar)(NMeAr') (L = DPPF, DPPF-OMe, DPPF-CF3, DPPF-OMe,Ph, DPPF-Ph,CF3, and DPPF-OMe,CF3; Ar = C6H4-4-CF3; Ar' = C6H4-4-CH3, Ph, and C6H4-4-OMe) underwent C-N bond forming reductive elimination at -15 C to form the c