Reiji Takeda

Microscale cleavage reaction of (phenyl)benzyl ethers by ferric chloride

Abstract Anhydrous FeCl3 in CH2Cl2 cleaves benzyl and p-phenylbenzyl ethers of sugars in 15–30 minutes and 2–3 minutes, respectively, at room temperature in >70% yields; methyl ethers and acyl groups are not affected.

The first isolation of lignans, megacerotonic acid and anthocerotonic acid, from non-vascular plants, anthocerotae (hornworts)

Abstract Two new lignans, megacerotonic acid and anthocerotonic acid, were isolated from the Anthocerotae (Hornworts), Megaceros flagellaris and Anthoceros punctatus. Their structures were determined by spectroscopic methods. This is the first known example of lignans isolated from non-vascular plants.

Ptychanolide, a sesquiterpenoid with a new type skeleton from the liverwort ptychanthus striatus (lehm. et lindenb.) nees

Abstract The structure of ptychanolide, isolated from the liverwort Ptychanthus striatus , has been determined by spectroscopic analysis and chemical transformation.

Two azulenes produced by the liverwort, Calypogeia azurea, during in vitro culture

Abstract Two new sesquiterpenoids, 4-methylazulene-1-carbaldehyde and 4-methylazulene-1-carboxylic acid, were isolated from cultures of Calypogeia azurea . Their structures were established by spectroscopic analysis. The sodium salt of 4-methylazulene-1-carboxylic acid was a naturally occurring water-soluble azulene that displayed anti-inflammatory and anti-ulcer activity.

Additivity in CD amplitudes of p-phenylbenzyl ethers and p-phenylbenzoates of 2-aminosugars

Abstract The additivity relation in amplitudes (A values) of split CD curves holds for p-phenylbenzyl ethers 1-12 and phenylbenzoates 13-28 of amino sugars. Thus the glycosidic linkage determination methods based on CD amplitudes are applicable to oligosaccharides containing amino sugars as well.

Zur Chemie der Proto-und allo-Proto-lichesterinsäure / Contribution to the Chemistry of Proto- and allo-Proto-lichesterinic Acids

The isolation and spectroscopic characterization of (-)-allo-proto-lichesterinic acid from Cetraria komarovii is described. Proto-lichesterinic and allo-proto-lichesterinic acids are transformed into numerous nitrogen-containing derivatives and the isomerization of the dihydro acids is investigated.