The photocatalytic activity of powdered TiO2 was increased enormously by supporting various catalysts such as Pt and RuO2·Water was decomposed into hydrogen and oxygen by using such photocatalysts. Interestingly, hydrogen evolution rate was enhanced remarkably by adding solid carbon or various organic compounds such as alcohols, carbohydrates or various biomasses to the aqueous suspension of the photocatalyst. For the decomposition of methanol and ethanol the quantum yield of hydrogen evolution exceeds 40-50 %. Those organic compounds were found to work as reducing agents and to be oxidized into CO2. Water was reduced photocatalytically to produce hydrogen. In addition to TiO2, various semiconductors which have the band gap in the visible wave-length region were found to evolve hydrogen by the same method. In the photocatalytic reactions of a large molecule such as carbohydrates with water, simple organic comounds such as methane, ethane, and ethanol were produced, showing some similarities with fermentation by microorganisms. The possibility of the application to organic synthesis was suggested. A water splitting system to produce hydrogen by using sun light was proposed combining these photocatalytic reactions with the photosynthesis of green plants.
The chemistry of carbonyl oxides is reviewed. Carbonyl oxides are known to be produced in the ozonolysis of olefins, and to react with carbonyl compounds, alcohols, and carboxylic acids. Such reactions are characterized as nucleophilicity of carbonyl oxide. Electrophilic and radical natures are also described in the reactions with hydrocarbons, aromatic compounds, olefins, sulfides, and sulfoxides. Oxygenations of diazo compounds and ylids can also produce carbonyl oxides. The intramolecular reactions of carbonyl oxides are also reported.
1977 witnessed almost simultaneous announcements of two completely independent syntheses of trans-doubly bridged ethylenes, one from Osaka University group and the other from Northwestern University group. This review provides a critical survey on the recent development in the chemistry of this unique and fascinating class of cyclic compounds with unsaturated center buried in the molecular cavity.
Highly stereocontrolled reduction of α-methyl β-keto esters, 3-hydroxy-2-methyl ketones, and α, β-epoxy ketones with Zn(BH4)2 has been described. In every case, the predominated products were found to be erythro-alcohols. A plausible mechanism to account for these high selectivity is discussed. Synthetic studies of erythronolide A starting from erythro-3-hydroxy-2-methylpropionates prepared by the reduction of the corresponding β-keto esters with Zn(BH4)2 have also been described.
This review deals with the synthetic studies on trichothecane-type sesquiterpenes and verrucarins. Although more than forty compounds were isolated from natural sources, only a few examples of total synthesis of natural products in this class have been reported. They are trichodermin, trichodermol, 12, 13-epoxytrichothec-9-ene, and trichodiene. The total synthesis of an important sesquiterpene, verrucarol, having tow hydroxyl groups at C-4 and C-15 positions, has not yet succeeded. However, some synthetic studies towards the total synthesis of verrucarol are discussed. In the last part, partial syntheses of macrocyclic derivatives of verrucarol, tetrahydroverrucarin J and 2'-deoxy-3'-hydroxytetrahydroverrucarin A, are described.
Recently a number of phenalenone derivatives have been reported. In this paper are described synthetic methods for monoaminophenalenones (i. e., 2-, 3-, 4-, 5-, 6-, 7-, and 9-aminophenalenone) which have been reported as dyes and its intermediates.
It is very interesting that the assay of hydrogen peroxide can be carried out by colorimetric, amperometric, chemiluminescent and other methods in clinical laboratory. Because hydrogen peroxide is generated by enzyme (oxidase) action from various biological substances. This methodology is now available in monitoring enzymeimmunoassay systems.