Abstract: Process for regiospecific preparation of new 3-hydroxypyridine-4(1H)-one derivatives starting from monosaccharides or itols of general formula: in which R represents a radical, either saturated or not, branched or not, having carbon-atom groups, and having hetero-atoms or not, and Sub represents a saccharide derivative or an itol, either cyclic not, protected or not, the hydrocarbon skeleton of which is bound to the nitrogen atom of the pyridinone either directly or by the intermediary of a spacing group. The present invention is characterized in that the process comprises a first step of protection of the 3-hydroxy group of the pyranone derivative, a second basocatalyzed step of substitution of the intracyclic oxygen atom of the pyranone by the nitrogen atom of the amine function of the amino monosaccharide or amino itol, and a third step of de-protection of the 3-OH group of the pyridinone cycle and possibly of the OH groups of the glucide or itol residue.

Abstract: Esters associating phenylacetic, 3-phenylpropionic, 4-phenylbutyric and n-butyric acids with Su(OH).sub.n monosaccharides or sugar alcohols, of general formula (I), in which the Su(OH).sub.n precursor is a monosaccharide or sugar alcohol, selected so that its structure or that of its derivatives ensures that internal interesterification does not take place either because the ester based on the general formula does not have a free hydroxyl grouping, or because with regard to the ester grouping, the free hydroxyl groupings are remotely located and/or badly aligned and/or bonded to a secondary carbon atom, and in which the Su(OH).sub.n monosaccharide or sugar alcohol is preferably D-mannose carrying the ester grouping on the anomeric carbon atom or else is a pentitol, for example, xylitol carrying the ester grouping on the C-1 primary carbon atom. These novel esters are useful as drugs, in particular in the treatment of haemoglobin diseases and premalignant or malignant tumours.