Yoshitatsu Ichihara

CONVOLUTAMYDINE A, A NOVEL BIOACTIVE HYDROXYOXINDOLE ALKALOID FROM MARINE BRYOZOAN AMATHIA CONVOLUTA

Abstract Convolutamydine A ( 1 ), a new alkaloid containing a dibromohydroxyoxindole moiety, was isolated from the Floridian bryozoan Amathia convoluta and the structure was elucidated on the basis of spectroscopic data. Compound 1 exhibited a potent activity in the differentiation of HL-60 cells.

Isolation and structure of convolutamydines B ∼ D from marine bryozoan Amathia convoluta

Abstract Convolutamydines B ∼ D (2 ∼ 4), three new alkaloids containing a dibromohydroxyoxindole moiety, were isolated from the Floridian bryozoan Amathia convoluta and the structures were elucidated on the basis of spectroscopic data. Convolutamydine B (2) has been found to exhibit a biological activity in the differention of HL-60 cells.

Nor-clerodane diterpenes from Croton cajucara

Abstract A new nor -clerodane diterpene, t -crotonin, was isolated from the cortices of Croton cajucara along with the previously isolated diterpene, of which the structure was not confirmed, dehydrocrotonin. The structures of these compounds were elucidated by chemical and spectroscopic methods.

Lathyrane diterpenes from Euphorbia lathyris

A new 7-hydroxylathyrol ester, L9, in addition to three known lathyrane diterpenes (L1, L3 and L8) have been isolated from the seeds of Euphorbia lathyris. The relative configurations of L9 were established by NOE experiments. 13C NMR data for these diterpenes are also reported.

ISOLATION AND STRUCTURE OF THE SYMMETRICAL DISTEROIDAL ALKALOIDS CEPHALOSTATIN 12 AND CEPHALOSTATIN 13

Abstract Re-examination of a Western Indian Ocean worm Cephalodiscus gilchristi has led to discovery of cephalostatins 12 and 13. Cephalostatin 12 ( 2 ) proved to be the first example of a symmetrical disteroidal alkaloid. Both new cephalostatins significantly inhibited growth of animal and human cancer cell lines.

SYNTHESIS OF 4-OXA-2-AZAPODOPHYLLOTOXIN, A NOVEL ANALOG OF THE ANTITUMOR LIGNAN PODOPHYLLOTOXIN

Abstract 4-Oxa-2-azapodophyllotoxin (5) has been synthesized from sesamol (6). 5 showed significant activity against adriamycin-resistant P-388 leukemia cells.

Isolation and structure of halistatin 3 from the Western Pacific (Chuuk) marine sponge Phakellia sp

The Micronesian marine sponge Phakellia sp. has been found to contain key members of the extraordinarily potent (antineoplastic) halichondrin/halistatin polyether macrolide family.

DITERPENES FROM CROTON-SALUTARIS

The twigs of Croton salutaris afforded three new acyclic diterpenes and a new tricyclic diterpene as well as a known compound, sonderianol. The structures of three acyclic diterpenes [(10E)-3,12-dihydroxy-3,7,11,15-tetramethyl-1,10,14-hexadecatrien-5,13-dione, (6E,10E)-3,12-dihydroxy-3,7,11,15-tetramethyl-1,6,10,14-hexadecatetraen-5,13-dione and (6Z,10E)-3,12-dihydroxy-3,7,11,15-tetramethyl-1,6,10,14-hexadecatetraen-5,13-dione] and a tricyclic diterpene [12-hydroxy-13-methylpodocarpa-9,11,13-trien-3-one] were determined by spectral methods.