Mitsuru Nakayama

Perilloside a, a monoterpene glucoside from Perilla frutescens

Abstract A new monoterpene glucoside named perilloside A has been isolated from the fresh leaves of Perilla frutescens . Its structure has been characterized on the basis of spectral and chemical evidence.

A phenylpropanoid glucoside from Perilla frutescens

Abstract The glycosidic constituents of two varieties of Perilla frutescens have been compared. A new phenylpropanoid glucoside named perilloside E has been isolated from the fresh leaves of the purple type plant. The structure was determined on the basis of spectral and chemical evidence.

(–)-Herbertene, an aromatic sesquiterpene with a novel carbon skeleton from the liverwort Herberta adunca

The structure of (–)-herbertene, an aromatic sesquiterpene hydrocarbon isolated from the liverwort Herberta adunca, has been determined as (1S)-1,2,2-trimethyl-m-tolycyclopentane (3) on teh basis of chemical and spectral evidence.

Monoterpene glucosides and other constituents from Perilla frutescens

Abstract Three new monoterpene glucosides named perilloside B-D have been isolated from the fresh leaves of Perilla frutescens. The structures were determined on the basis of spectral and chemical evidence.

(–)-Myltaylenol, a tricyclic sesquiterpene alcohol with a novel carbon skeleton from the liverwort Mylia taylorii

A sesquiterpene alcohol (–)-myltaylenol with a novel carbon skeleton has been isolated from the liverwort Mylia taylorii, and its structure (3), including the absolute configuration, has been determined on the basis of chemical and spectroscopic evidence as well as X-ray analysis of the benzoate derivative (7).

(1R,6R,9S,10S)-9-Chloro-10-hydroxy-8-methoxycarbonyl-4-methylene-2,5-dioxabicyclo[4.4.0]Dec-3-one-7-ene, a first chlorine-containing shikimate-related metabolite from fungi

Abstract A new chlorine-containing metabolite has been isolated from two fungi, and its structure including absolute stereochemistry was established by spectroscopic and X-ray crystallographic studies.

γ-selective hydroxylation of α,β,γ,δ-unsaturated carbonyl compounds and its application to syntheses of (±)-6-hydroxyshogaol and related furanoids

Abstract α,β,γ,δ-Unsaturated carbonyl compounds were converted regioselectively into γ-hydroxy-α,β-unsaturated carbonyl compounds by reduction-oxygenation with molecular oxygen and triethylsilane in the presence of cobalt(II) porphyrin as a catalyst followed by treatment with trimethyl phosphite. (±)-6-Hydroxyshogaol and related furanoids isolated from ginger were synthesized via this method.

Structures and conformations of (―)-isobicyclogermacrenal and (―)-lepidozenal, two key sesquiterpenoids of the cis- and trans-10,3-bicyclic ring systems, from the liverwort Lepidozia vitrea: X-ray crystal structure analysis of the hydroxy derivative of (―)-isobicyclogermacrenal

The structures and absolute configurations of the two sesquiterpene aldehydes, (–)-isobicyclogermacrenal (1) and (–)-lepidozenal (2), which were isolated from the liverwort Lepidozia vitrea, have been determined on the basis of chemical and spectroscopic evidence to be (6R,7S)-6,11-cyclogermacra-1(10)-E,4E-dien-14-al and (6R,7S)-lepidoza-1 (10)E,4E-dien-14-al, consisting of the cis- and trans-10,3-bicyclic ring systems. The structure of the former (1) has been confirmed by a single-crystal X-ray analysis of its hydroxy derivative (7). The molecular conformations, biogenetical features, and biological activity are also described.

A novel quasi-dimeric oxidation product of (+)-catechin from lipid peroxidation

A novel quasi-dimeric oxidation product of (+)-catechin, formed during the radical-scavenging reaction that prevents lipid peroxidation, was isolated by chromatography, and its structure was elucidated by infrared, ultraviolet and1H and13C nuclear magnetic resonance spectra and mass spectrometry. It was 5′-[3-[3,4-(3′,5′-dihydroxy) benzo-8-oxo-2,7-dioxabicyclo [4.4.0] deca-3,9-dien-10-yl]acryloyl]-(+)-catechin. It is an unusual type of dimer of flavan-3-ol derivatives, which is different from the naturally formed dimer, procyanidin.

Structures of ent-herbertane sesquiterpenoids displaying antifungal properties from the liverwort Herberta adunca

Several aromatic sesquiterpenoids displaying antifungal properties have been isolated from the liverwort Herberta adunca together with a mother hydrocarbon with a novel irregular sesquiterpene skeleton, ent-herbertane, and their structures and absolute configurations have been determined on the basis of extensive degradation reactions and spectroscopic evidence. The biological activity is also described.