Abstract: A process for removing osmium from an aqueous solution of nucleosides comprising adding hydrogen sulfide, an aromatic pi base such as pyridine, and a mineral acid. The osmium is precipitated out of solution.

Abstract: Synthesis of the triol of formula (I) or its amine-protected derivative from a cyclopentene of the formula (II) or its amine-protected derivative: ##STR1## via steps including oxidation to the aldehyde, migration of the double bond, reduction of the aldehyde moiety back to the alcohol grouping and 1,2-cis-dihydroxylation of the double bond.

Abstract: The invention concerns a process for preparng a thiazolo[3,2-a]benzimidazole of formula I ##STR1## in which formula n is 1 or 2, and R.sub.1 is hydrogen, lower alkyl, lower alkoxy, trifluoromethyl or halo, or a salt thereof which comprises dehydrating a compound of formula II, ##STR2## or a salt thereof wherein n and R, are a defined above, and COOR is an acid or ester function in the presence of an acid selected from sulphuric, sulphonic and phosphoric acid or mixtures thereof and if desired or required an inert solvent provided that if water is present then the amount of water is less than about 15% by volume of the acid, the reaction being carried out with heating if necessary.

Abstract: The invention concerns a process for preparing a thiazolo[3,2-a]benzimidazole of formula I ##STR1## in which formula n is 1 or 2, and R.sub.1 is hydrogen, lower alkyl, lower alkoxy, trifluoromethyl or halo, or a salt thereof which comprises dehydrating a compound of formula II, ##STR2## or a salt thereof wherein n and R, are as defined above, and COOR is an acid or ester function in the presence of an acid selected from sulphuric, sulphonic and phosphoric acid or mixtures thereof and if desired or required an inert solvent provided that if water is present then the amount of water is less than about 15% by volume of the acid, the reaction being carried out with heating if necessary.