Masayuki Shibuya

Efficient Synthesis of Oligo-N-methylpyrrolecarboxamides and Relateed Compounds

A partir de methyl-1 nitro-4 pyrrolecarboxamides-2 et de methyl-1 nitro-4 trichloroacetyl-2 pyrrole, synthese de methyl-1 [methyl-1 nitro-4 pyrrolecarbonyl-2amino]-4 pyrrolecarboxamide-2 puis du tripeptide correspondant

Synthesis of the naphthalenecarboxylic acid derivative obtained from neocarzinostatin (NCS): a structure revision

Abstract The structure of the naphthalenecarboxylic acid derivative obtained from neocarzinostatin (NCS) was revised as methyl 2-hydroxy-7-methoxy-5-methyl-1-naphthalenecarboxylate ( 2a ) by its synthesis.

Tripterygium wilfordii var. regelii which are interleukin-1 inhibitors

Abstract Seven new quinoide-type diterpenes were isolated from the stems of Tripterygium wilfordii var. regelii and their structures were established on the basis of spectroscopic and chemical evidence. The isolated compounds showed extremely potent inhibitory activities against interleukin-lα and β releases for human peripheral mononticlear cells.

Cycloaromatization of a 10-membered enediyne derivative via an allenic sulfone intermediate and its DNA cleaving activity

Abstract Synthesis of the sulfone containing 10-membered enediyne derivative 3 and its cycloaromatization in basic conditions via an allenic sulfone intermediate as well as its DNA cleaving activities are described.

Triptoquinone A and B novel interleukin-1 inhibitors from Tripterygium wilfordii var Regeli

Abstract Novel interleukin-1 inhibitors, triptoquinone A (1) and B(2), have been isolated from Tripterygium wilfordii v a r regelli, and their structures were elucidated mainly by spectroscopic methods including X-ray.

Synthesis of a sulfulr-containing 10-membered enediyne model compound related to the esperamicin/calicheamicin/dynemicin agylcones

Abstract Synthesis of the 10-membered heterocyclic enediyne 4 and its conversion to the benzenoid adduct 10 via the Bergman reaction are described.

Fluorescent pigments by covalent binding of lipid peroxidation by-products to protein and amino acids.

The fluorescent products formed on reaction of 12-oxo-cis-9-octadecenoic acid (12-keto-oleic acid) with about 20 different amino acids, polylysine and bovine serum albumin (BSA) were studied. Besides glycine, only the basic amino acids histidine, lysine and arginine gave products with strong fluorescence. N-Acetylation of amino acids greatly reduced the fluorescence of their reaction products. The formation of fluorescent products was inhibited strongly by SH-amino acids such as N-acetyl-cysteine and glutathione. Polyacrylamide gel electrophoresis showed that BSA treated with 12-keto-oleic acid was more acidic than untreated or ricinoleic acid-treated BSA, indicating that basic amino acid residues in BSA were modified by reaction with the keto fatty acid. None of the structural analogs of 12-keto-oleic acid tested–12-oxo-trans-10-octadecenoic acid, 12-oxo-octadecanoic acid, 12-hydroxy-cis-9-octadecenoic acid (ricinoleic acid),cis-9-octadecenoic acid (oleic acid) and linoleic acid—reacted with glycine to give a fluorescent product. The fluorescent products formed on reaction of 12-keto-oleic acid methyl ester with benzyl amine and glycine methyl ester were shown to be 8-(N-substituted-4,5-dihydro-4-oxo-5-hexyl-5-hydroxy-2-pyrrolyl) octanoic acid methyl esters. The fluorescence properties of these compounds were attributed to the chromophobic system NC=CC=O which contains 6π electrons. This investigation contributes to insight of the mechanism of formation of fluorescent pigments, probably by a similar reaction of other compounds of the β,γ-unsaturated carbonyl type.

An efficient total synthesis of (−)-mintlactone and (+)-isomintlactone

Abstract Total synthesis of (−)-mintlactone and (+)-isomintlactone has been achieved diastereoselectively via a fused butenolide construction strategy based on an intramolecular [3+2] cycloaddition reaction of nitrile oxide.

A CONVENIENT SYNTHESIS OF ACYCLIC CONJUGATED ENEDIYNES

Abstract Novel synthetic method for acyclic cis -hex-3-ene-1,5-diyne derivatives via elimination of tert -hydroxy group has been described.

Novel and facile route to (+)-physovenine via intramolecular [2+2]cycloaddition reaction

Abstract A formal total synthesis of (±)-physovenine 1 from 2-amino-5-methoxyacetophenone 2 via an intramolecular [2+2]cycloaddition reaction is described.