Palladium-Catalyzed 1,1-Alkynyloxygenation of 2-Vinylbenzoates with Alkynyl Bromides.

The palladium-catalyzed reaction of alkyl 2-vinylbenzoates with silyl-protected alkynyl bromides leads to the selective production of 3-alkynylated isochroman-1-ones. The use of an alkyl ester group as an effective oxygen nucleophile is crucial for the efficient 1,1-alkynyloxygenation of alkenes.

Tigliane-Type Diterpene Esters from the Fruits of Shirakiopsis indica and Their Anti-HIV Activity.

Four new diterpene esters, shirakindicans A-D (1-4), along with eight related known diterpene esters (5-12), were isolated from the fruits of the Bangladeshi medicinal plant Shirakiopsis indica. The structures of 1-4 were elucidated by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Shirakindican A (1) was assigned as a tigliane-type diterpene ester possessing an unusual 6ß-hydroxy-1,7-dien-3-one structure, while shirakindican B (2) exhibits a tiglia-1,5-dien-3,7-dione structure. The anti-HIV activities of the isolated diterpene esters were evaluated and showed significant activities for sapintoxins A (5) and D (11), with EC50 values of 0.0074 and 0.044 µM, respectively, and TI values of 1 100 and 5 290. Sapatoxin A (12) also exhibited anti-HIV activity with an EC50 value of 0.13 µM and a TI value of 161.

Studies on non-medicinal parts of plant materials: Triterpenes from the roots of Schisandra chinensis.

Phytochemical study on a non-medicinal part of a plant material for herbal medicine, the roots of Schisandra chinensis, was conducted to isolate five new triterpenes, schinensins A-D (1-4) and 3-O-methylchangnanic acid (5), together with 21 known compounds including 10 triterpenes, one sterol, two sesquiterpenes, seven lignans, and one flavonoid. The structures of new triterpenes (1-5) were assigned on the basis of spectroscopic analyses aided with TDDFT ECD calculations. Schinensin A (1) was a dinortriterpene possessing 28-norschiartane skeleton, while schinensins B-D (2-4) were assigned as 3,4:9,10-disecocycloartane, 3,4-secocycloartane, and cycloartane triterpenes, respectively. In an evaluation of antiproliferative activities against human cancer cell lines, some triterpenes exhibited significant activities against human breast carcinoma MCF-7 cells as compared to the other cell lines (A549, HeLa, and RPMI8226).

Diterpenes from an Uzbek medicinal plant Perovskia scrophulariifolia: Their structures and anti-neuroinflammatory activity.

Phytochemical investigation on the aerial parts of a Lamiaceous medicinal plant Perovskia scrophulariifolia collected in Uzbekistan resulted in the isolation of two new 20-norabietane diterpenes, along with thirteen known diterpenes including one 20-norabietane, eight abietanes, one 6,7-secoabietane, and three icetexanes. The structures of new 20-norabietane diterpenes, perovsfolins C (1) and D (2), were elucidated by spectroscopic analyses aided with calculations of ECD spectra. Perovsfolin C (1) is the first 20-norabietane diterpene possessing a 1,11-epoxy moiety, while perovsfolin D (2) is a 20-norabitetane diterpene with a 2-hydroxy-1,4-quinone moiety as C-ring. Anti-neuroinflammatory activity of the isolated diterpenes on microglial cells was evaluated.

Agesasines A and B, Bromopyrrole Alkaloids from Marine Sponges Agelas spp.

Exploration for specialized metabolites of Okinawan marine sponges Agelas spp. resulted in the isolation of five new bromopyrrole alkaloids, agesasines A (1) and B (2), 9-hydroxydihydrodispacamide (3), 9-hydroxydihydrooroidin (4), and 9E-keramadine (5). Their structures were elucidated on the basis of spectroscopic analyses. Agesasines A (1) and B (2) were assigned as rare bromopyrrole alkaloids lacking an aminoimidazole moiety, while 3-5 were elucidated to be linear bromopyrrole alkaloids with either aminoimidazolone, aminoimidazole, or N-methylated aminoimidazole moieties.