Abstract: The present invention relates to a photochemical process for the manufacture of hydrogen peroxidewherein a 9,10-phenanthraquinone compound is exposed, in the presence of an effective amount of a hydrogen donor alcohol, to electromagnetic radiation to photoreduce the 9,10-phenanthraquinone compound to the correpsonding dihydro-compound,wherein the dihydro-compound obtained is oxidized to produce hydrogen peroxide and to regenerate the 9,10-phenanthraquinone compound, andcharacterized in that said 9,10-phenanthraquinone compound is selected from the group of compounds consisting of unsubstituted 9,10-phenanthraquinone and 9,10-phenanthraquinone substituted by one or more members of the class consisting of alkyl groups of 1 to 8 carbon atoms, --CF.sub.3, F and --SO.sub.3 M, M being H or an alkali metal.

Abstract: Photochemical conversion of tachysterols to previtamins is conducted in the presence of a polymeric photosensitizer which has the appropriate chromophore groups, e.g. anthracene groups, attached to a medium or high molecular weight, substantially uncrosslinked polymer backbone. The polymeric photosensitizer is soluble in solvents normally used for conducting the photochemical reaction (diethyl ether, dioxane, THF, t.butyl methyl ether) but insoluble in lower alcohols and hydrocarbons, so that it may be readily and simply recovered from the product mixture by use of such non-solvents.

Abstract: A process for electrochemically reducing 7-ketolithocholic acid to ursodeoxycholic acid is disclosed. The process may be conducted alone or in conjunction with a simultaneous electrochemical oxidation of chenodeoxycholic acid to 7-ketolithocholic acid. Solvents for the electrochemical reaction which promote stereoselectivity to ursodeoxycholic acid are also disclosed.

Abstract: A process for preparing ampicillin trihydrate is disclosed which comprises acylating silylated 6-aminopenicillanic acid with D(-)-.alpha.-phenylglycylchloride hydrochloride directly in the silylation reaction mixture in the presence of urea as an acid acceptor, hydrolyzing the reaction product and precipitating ampicillin-trihydrate from the resulting aqueous solution. The amounts of reactants, in particular of solvents and water, are adjusted to provide good yields of a product of high purity.