Tohru Yasuzawa

Four new prostanoids: Claviridenone-A, -B, -C, and -D from the okinawan soft coral Clavularia viridis

The structures of four new prostanoids named claviridenone-a, -b, -c, and -d, which were isolated from the Okinawan soft coral Clavularia viridis, were elucidated as 1, 2, 3, and 4, respectively.

New prostanoids from soft coral

Abstract Four new anti-tumor active prostanoids, named claviridenone-a (3), claviridenone-b (4). claviridenone-c (5), and claviridenone-d (6), as well as 20-acetoxy-claviridenone-b (7) and 20-acetoxy-claviridenone-c (8), have been isolated from the Okinawan soft coral (stolonifer) Clavularia viridis Quoy and Gaimard (Stolonifera, Clavulariidae). The absolute stereostructures of these six prostanoids have been elucidated on the basis of chemical and physicochemical evidence which includes the application of the CD exciton chirality method to their various benzoyl derivatives having benzoate and conjugated diene chromophores. Claviridenones possess a characteristic cross-conjugated dienone-enone chromophore.

Alcyonolide, a novel diterpenoid from a soft coral

Abstract A novel diterpenoid acetate named alcyonolide has been isolated from an Okinawan soft coral of the genus Alcyonium and the absolute stereostructure 1 has been assigned on the basis of chemical and physicochemical evidence.

Structure of paxisterol, a sterol from Penicillium paxilli

The complete structure of paxisterol 1, produced by a Penicillium species, was determined by means of spectral and chemical studies of the parent compound and several of its derivatives. Paxisterol is a unique sterol, having an acetal structure at C-18. Application of 2D-INADEQUATE technique in 13C NMR spectral analysis was useful in this structure determination, where all carbon-carbon bonds in the molecule were demonstrated. Absolute stereochemistry was confirmed by the CD spectrum of 3-keto derivative 10 of compound 1 to be the same as that of cholesterol. An interesting acetal migration reaction was observed during the chemical conversions.