Etsuro Kurosawa

Teurilene and thyrsiferyl 23-acetate, meso and remarkably cytotoxic compounds from the marine red alga laurencia obtusa (hudson) lamouroux

Abstract Two new cyclic ethers consisting of squalene carbon skeleton have been isolated from the red alga L. obtusa . The absolute stereostructure of teurilene ( 1 ) was elucidated by x-ray crystallographic method, and the structure of thyrsiferyl 23-acetate ( 2 ) was established from the spectral and chemical evidence.

Laurinterol, debromolaurinterol and isolaurinterol, constituents of Laurencia intermedia Yamada

Abstract A new type of sesquiterpenoid containing bromine and its debromo analog, laurinterol (I) and debromolaurinterol (II), as well as an isomeric bromo compound, isolaurinterol (III), have been isolated from Laurencia intermedia Yamada (Rhodomelaceae), and their structures determined.

Laureatin and isolaureatin, constituents of Laurencia nipponica Yamada☆

Abstract Laureatin and isolaureatin, new bromo compounds isolated from Laurencia nipponica Yamada, are shown to possess structures I and II, respectively.

Laurene, a sesquiterpene hydrocarbon from Laurencia species.

Abstract Laurene, a new sesquiterpene hydrocarbon from Laurencia glandulifera Kutzing and L. nipponica Yamada, is shown to possess structure I. Isolaurene (IV) and epilaurene (XX) have been synthesized.

The absolute configurations of halogenated chamigrene derivatives from the marine alga, laurencia glandulifera kützing

Abstract The absolute configurations of halogenated chamigrene derivatives, isolated from L. glandulifera Kutzing, 10-bromo-3,4-epoxy-α-chamigrene (1), glanduliferol (2), 10-bromo-α-chamigren-4-one (3), 4,10-dibromo-3-chloro-α-chamigrene (4) and 10-bromo-α-chamigrene (5), have been determined by X-ray diffraction analysis of 1 and subsequently, by relating 2, 3, 4 and 5 to 1 with the chemical methods. In addition, the absolute configuration of (−)-α-chamigrene (6), yielded on the process of the above chemical transformation, has been elucidated.

A C-15 non-terpenoid from the red alga Laurencia okamurai

Abstract The structure of a new C-15 bromoallene from the red alga Laurencia okamurai was deduced by spectral methods.

Laurallene, new bromoallene from the marine red alga Laurencia nipponica Yamada☆

Abstract Laurallene ( 1 ), a new brominated cyclic ether having a terminal allene moiety, has been isolated as a main constituent from the marine red alga Laurencia nipponica Yamada (Rhodomelaceae, Rhodophyta) and its structure was determined by its physical and chemical properties.

Okamurallene, a novel halogenated C15 metabolite from the red alga laurencia okamuhai yamada

Abstract Okamurallene ( 1 ), a novel nonterpenoid C 15 bromoallene containing cyclopropane ring, has been isolated from the red alga Laurencia okamurai Yamada and its structure was determined by the spectral evidence.

Laureepoxide, new bromo ether from the marine red alga Laurencia nipponica Yamada☆

Abstract An interesting bromine containing compound, laureepoxide ( 1 ), has been isolated from L . nipponica Yamada (Rhodomelaceae, Rhodophyta) and its structure has been determined by the chemical degradations and spectral properties.

Structure revision of okamurallene and structure elucidation of further C15 non-terpenoid bromoallenes from Laurencia intricata

Abstract The structures of okamurallene related metabolites, which have previously been isolated from the red alga Laurencia intricata , have been revised. In addition, two new C 15 non-terpenoid bromoallenes with a halohydrin moiety have also been obtained, and their structures determined by chemical and spectroscopic methods.