Yoshinobu Inouye

Absolute configurations of cytotoxic marine cembranolides; Consideration of mosher's method

Abstract Stereochemistry of the cembranolides 1 and 5 , isolated from the soft coral Sinularia mayi , has been elucidated by means of 2D NMR spectroscopy and X-ray crystallography. The absolute configuration of denticulatolide 6 has been determined by X-ray analysis, and the validity of Moshers method is discussed as to the MTPA esters 3 , 4 , 7 , and 8 .

New chiral anisotropic reagents, NMR tools to elucidate the absolute configurations of long-chain organic compounds

Abstract Modified Moshers method has been extended by use of 9-anthranylmethoxyacetic acid (9ATMA) and 2-naphthylmethoxynaphthylacetic acid (2NMA) instead of MTPA of the conventional method. Anisotropic effects of these reagents are much greater than that of MTPA, and the reagents have been shown to be useful especially to determine the absolute configurations of the secondary alcohols involved in long-chain compounds.

Stolonidiol, a new marine diterpenoid with a strong cytotoxic activity from the Japanese soft coral

Abstract Structures of stolonidiol ( 1 ) and stolonidiol monoacetate ( 2 ), new marine diterpenoids with a strong cytotoxic activity from the Japanese soft coral Clavularia sp., were established by means of spectroscopic analyses, chemical reactions, and X-ray crystallographic analysis.

Structures of nine oxygenated 4-methylene sterols from Hachijo marine sponge Theonella swinhoei.

Nine new sterols have been isolated from a marine sponge, Theonella swinhoei. Of these, seven sterols were found to be conicasterol derivatives [(24R)-4-methylene-24-methyl-8(14)-cholesten-3 beta-ol] oxygenated at carbon-7 and/or carbon-15. The other two were (24R)-7 beta,8 beta-epoxy-14 alpha-methoxy-4-methylene-24-methylcholestan- 3 beta-ol and (24R)-8,14-seco-8,14-dioxo-4-methylene-24-methylcholestan-3 beta-ol.

Inhibition of the formation of adventitious roots on cucumber hypocotyls by the fractions and methoxybenzylglutamine from xylem sap of squash root

In studies of the functions of roots in the development of aboveground organs, the butanol fraction of xylem sap collected from squash root was found to have inhibitory activity against the formation of adventitious roots on the hypocotyls of cucumber in a culture of shoot cutting. The inhibitory activity was fractionated with reverse phase column chromatographies, and an inhibitory fraction was recovered with a single peak of absorbance at 280 nm, which contained a novel amino acid,N5-(4-methoxyphenyl) methyl-l-glutamine (methoxybenzylglutamine) as a major component (Inouyeet al. 1998). Chemically synthesized methoxybenzylglutamine (5 mM) inhibited the formation of adventitious roots and also inhibited the growth of first leaf and cotyledons in a culture of shoot cuttings. On the basis of the results obtained, discussed is possible regulation of the developmental events on the aboveground organs by the roots through xylem sap.

Chromotropism of imidazole derivatives. Part 1. 4,5-Bis-(4-methoxyphenyl)-2-(4-nitrophenyl)imidazolium acetate dihydrate

4,5-Bis-(4-methoxyphenyl)-2-(4-nitrophenyl)imidazolium acetate dihydrate (1) in the crystalline state exhibits a sensitive colour change from orange-yellow to red on treatment by various methods (drying, trituration, or heating). The colour change was reversible below 70 °C but above 70 °C the change was irreversible and the colour deepened. Compound (1) was deprotonated with the loss of one mole of water of crystallization under treatment and can revert to the original by absorption of one mole of water. On heating to 100 °C, (1) lost all solvent of crystallization to give a deep red material (2). (2) Was considered to be 4,5-bis-(4-methoxyphenyl)-2-(4-nitrophenyl)imidazole which was linked by hydrogen bond from the imino group in one molecule to the nitro oxygen in another. Compound (2) reverted to (1) in saturated AcOH–H2O vapour.

N5-(4-Methoxyphenyl)methyl-L-glutamine in xylem sap from squash root

Abstract A new amino acid derivative, N 5 -(4-methoxyphenyl)methyl- l -glutamine was found in the xylem sap from squash root. The structure was deduced from spectroscopic data and identified by chemical synthesis.

Polymorphisms and Colourations of 4,5,-Bis(4-Methoxyphenyl)-2-(3-Nitrophenyl0–1H-Imidazole

Abstract 4,5-Bis(4-methoxyphenyl)-2-(3-nitrophenyl)-1H-imidazole [I] crystallized in several coloured states such as red, orange, yellow, by changing solvents. From X-ray powder diffraction, d.s.c. thermograms and I.R. spectra, the red and the two yellow crystals were found to be polymorphic forms of [I]. The polymorphisms are based on differencies in the hydrogen bonds. The red crystals have a hydrogen bond of the type ‒NH—O˭. The NH hydrogen of one molecule bonds to the nitro oxygen of another. One of the two yellow crystals has hydrogen bonds of the type -NH—N =. The NH of one molecule bonds to the nitrogen on the others imidazole ring. Another yellow crystal has two kinds of hydrogen bonds, -NH—N= and -NH—OMe-, the NH of one molecule with the methoxy oxygen of another molecule. On the other hand, the orange crystals have solvent of crystallization. The solvent was connected with the imidazole ring and hinders direct hydrogen bonding between two imidazole rings. Colouration of the red crystals is due ...

Solid-state NMR and X-ray diffractional analysis of conformational effects in σ-symmetric bicyclo[2.2.1]hept-2-ene diester and monoesters

Abstract Solid state NMR and X-ray crystallographic analysis have proven that dissymmetrization by enzymatic asymmetric hydrolysis of meso bicyclo[2.2.1]hept-2-ene(norbornene) diesters does not induce significant electron distortion of the olefinic bond.

Simple and Excellent Preparation of Polymorphic Crystals of 4,5-Bis(4-Methoxyphenyl)-2-(3-Nitrophenyl)-1H-Imidazole

Abstract The title imidazole 1 forms inclusion complexes with ethyl acetate, tert-BuOH, and benzene. The complexes lost their guest molecule to give polymorphic crystals A, B, C and D in a pure state. A is red plates, B is yellow needles, C is pale yellow silky needles and D is light yellow cottony needles. The polymorphic crystal turns to the other one when the crystal contacts with organic vapor. The reactivity decreased with B>D>C>A. Structure and reactivity of the polymorphic crystals are discussed on the type of hydrogen bonding and on molecular arrangements in crystals.