Masako Akaji

MONOTERPENOID AND PHENYLETHANOID GLYCOSIDES FROM LIGUSTRUM PEDUNCULARE

Two new phenylethanoid glycosides, lipedosides A-I and A-II as well as six new monoterpene glycosides, lipedosides B-I-B-VI were isolated together with three known constituents, osmanthuside B, anatolioside and linalool from Ligustrum pedunculare. Their structures have been elucidated by chemical and spectroscopic methods.

Synthesis of cyclic RGD derivatives via solid phase macrocyclization using the Heck reaction

Abstract A novel intramolecular macrocyclization reaction on a solid support using the Heck reaction has been achieved. For head to tail cyclization on a solid support, the linear precursor was anchored to a chlorotrityl chloride resin via an ester linkage using the β-carboxyl group of Asp. The Heck coupling of acrylic acid amide to 3-iodobenzylamine on the solid support proceeds smoothly to yield a cyclic tetrapeptide derivative, which contains a new 3-substituted cinnamic acid template and Arg-Gly-Asp sequence. The macrocyclization reaction takes place considerably more rapidly on a solid support than in solution. The solid phase procedure was successfully used for the construction of cyclic RGD libraries having diverse side chain structures, combined with a variety of ring sizes.

Secoiridoid glucosides from Fraxinus malacophylla

Abstract Two new secoiridoid glucosides, butyl isoligustrosidate and fraximalacoside, were isolated from the leaves of Fraxinus malacophylla, together with the known constituents, isoligustroside, fraxiformoside, isoligustrosidic acid, 1′″-O-β- d -glucosylfraxiformoside, verbascoside, cosmosiin, sitosterol-β- d -glucoside and tyrosol. Their structures have been elucidated by chemical and spectroscopic methods.

An aza-Payne rearrangement-epoxide ring opening reaction of 2-aziridinemethanols in a one-pot manner: A regio- and stereoselective synthetic route to diastereomerically pure N-protected 1,2-amino alcohols

Abstract A regio- and stereoselective synthetic route to diastereomerically pure 1,2-amino alcohols via a one-pot aza-Payne rearrangement - epoxide ring opening reaction of 2-aziridinemethanols is reported.

A thermodynamic preference of chiral cis-γ,δ-epimino-(E)-α,β-unsaturated esters over other stereoisomers: Synthetically useful Pd(0)-catalyzed equilibrated reactions of aziridines bearing an α,β-unsaturated ester group

Abstract A practical synthesis of chiral N -arylsulfonyl- cis - γ , δ -epimino-( E )- α , β -enoates, key intermediates for the synthesis of ( E )-alkene dipeptide isosteres via Pd(0)-catalyzed equilibrated reactions, has been successfully achieved by exposing N -arylsulfonyl-γ,δ-epimino-α,β-unsaturated esters to a catalytic amount of Pd(PPh 3 ) 4 in THF at 0 ∼ 20 °C.

One-pot transformation of p-toluenesulfonates of 2,3-epoxy alcohols into allyic alcohols

Abstract A convenient and efficient method for the synthesis of synthetically useful non-racemic allylic alcohols from 4-methylbenzenesulfonates of non-racemic 2,3-epoxy alcohols is described. Satisfactory yields are obtained by treatment of 4-methylbenzenesulfonates of non-racemic 2,3-epoxy alcohols with potassium iodide followed by zinc powder and ammonium chloride in a one-pot manner. The method has been successfully applied to the synthesis of a key building block of C 30 C 37 botryococcenes.

Simple one-pot transformations of toluene-p-sulfonates of 2,3-epoxy alcohols into allylic alcohols

A simple synthetic method for the preparation of scalemic allylic alcohols from toluene-p-sulfonates of scalemic 2,3-epoxy alcohols is reported. Satisfactory yields are obtained by treatment of toluene-p-sulfonates of 2,3-epoxy alcohols with potassium iodide followed by triphenylphosphine and iodine in a one-pot synthesis.