Abstract: The invention relates to a process for preparing .alpha.-amino acid amides, the corresponding .alpha.-amino acids, or salt thereof, which are substituted at the .beta.-site with at least one (hetero)aromatic group. This is achieved according to the invention by subjecting a 4-carbamoyl-2-oxazolidinone compound, respectively a 4-carboxy-2-oxazolidinone compound, wherein each of them is substituted at the 5-site with at least one (hetero)aromatic group, to a treatment with H.sub.2 in the presence of a catalyst. The invention also relates to a process for preparing a 4-carbamoyl-2-oxazolidinone compound substituted at the 5-site with at least one (hetero)aromatic group, in which process an .alpha.-amino-.beta.-hydroxy-propane nitrile substituted at the .beta.-site with at least one (hetero)aromatic group, or a salt thereof, is subjected to a treatment in the presence of CO.sub.2 and a base.

Abstract: Process for the preparation of a heterocyclic o-dicarboxylic acid containing at least one N atom, in which a corresponding benzo-fused heterocyclic compound containing at least one N atom is oxidised in the presence of hydrogen peroxide, a Bronsted acid and an iron compound.Preferably Fe(NO.sub.3).sub.3 is used as the iron compound and HNO.sub.3 as the Bronsted acid. The amount of iron compound to be used preferably lies between 0.1 and 2 mol. %, relative to the amount of employed benzo-fused heterocyclic compound containing at least one N atom. Even higher yields can be obtained if a copper compound or an organic electron-transferring compound is also used, in addition to the iron compound.In particular, the process according to the invention can be used to prepare 2,3-pyridine dicarboxylic acids from corresponding quinoline compounds.