Four-electron reduction of benzene by a samarium(II)-alkyl without the addition of external reducing agents.

Benzene reduction by molecular complexes remains an important synthetic challenge, requiring harsh reaction conditions involving group I metals. Reductions of benzene, to date, typically result in a loss of aromaticity, although the benzene tetra-anion, a 10π-electron system, has been calculated to be stable and aromatic. Due to the lack of sufficiently potent reductants, four-electron reduction of benzene usually requires the use of group I metals.

Natural and Semisynthetic Immunomodulatory Luakuliide Labdane Diterpenoids.

Spectroscopy-guided isolation of extracts of the Tongan marine sponge cf. (Lamarck, 1814) has resulted in the reisolation of the labdane diterpenoid luakuliide A () and one new congener, luakulialactam A (). In addition to establishing the absolute configuration of , synthetic modifications to the luakuliide framework at key positions has created a set of six derivatives (-) which were used to interrogate a structure-activity relationship relating to the immunomodulatory effects of luakuliide A.

Geographical distribution of freshwater fishes in Saudi Arabia.

Species presence/absence data in different water bodies in different regions of Saudi Arabia were collated from the literature and collected from field surveys to determine the geographical distribution of fish species in the country. Freshwater fish are mainly located in drainages in the south-west of the Kingdom of Saudi Arabia, both in the lowlands (western drainage systems) and highlands (eastern drainage systems) of the Sarawat Mountain Range. The eastern drainage systems were dominated by three endemic species, while the western drainage systems had a variety of endemic and non-native species.