Abstract: The invention relates to a process for the preparation of an oligopeptide or amino acid alkyl ester.HCl salt, the alkyl group being methyl, ethyl, isopropyl or n-propyl, by converting an oligopeptide.HCl salt or amino acid.HCl salt with an alkanol corresponding to the alkyl group under the influence of an acid catalyst, 0.01-0.5 mol HCl relative to the oligopeptide.HCl salt or amino acid.HCl salt in combination with an acid ion exchange resin being used as acid catalyst.

Abstract: The invention relates to a process for preparing a 2-alkyl-1,4,5,6-tetrahydropyrimidine with the formula ##STR1## where R represents a straight or branched chain with 1-8 C-atoms or a phenyl group from 1,3-diaminopropane and an alkanecarboxylic acid, in which the alkyl group of such an acid is the same as the R group described above, wherein the starting materials are reacted in the gas phase in the presence of an oxide catalyst at a temperature of between 250.degree. and 450.degree. C. and from the reaction mixture thus obtained the 2-alkyl-1,4,5,6-tetrahydropyrimidine is recovered.

Abstract: The invention provides a process for the preparation of pyrimidine, 2-methyl- and/or 2-ethylpyrimidine, characterized in that for pyrimidine a nitrogen reactant, chosen from the reaction product of formamide with 1,3-diaminopropane in the liquid phase, 1-amino-3-formamidopropane, 1,4,5,6-tetrahydropyrimidine and/or 1,3-diformamidopropane, that for 2-methylpyrimidine 1-amino-3-acetamidopropane, 2-methyl-1,4,5,6-tetrahydropyrimidine and/or 1,3-diacetamidopropane, and that for 2-ethylpyrimidine 1-amino-3-propionamidopropane, 2-ethyl-1,4,5,6-tetrahydropyrimidine and/or 1,3-dipropionamidopropane is/are contacted with a palladium-containing catalyst, this being effected in the gas phase at a temperature between 200.degree. and 550.degree. C. and in the presence of a carbon monoxide-hydrogen reactant, and that pyrimidine, 2-methyl-and/or 2-ethyl-pyrimidine is recovered from the reaction mixture obtained.

Abstract: The process according to the invention for the preparation of a 2-propyl- or 2-butylpyrimidine, in which the corresponding 2-alkyl-1,4,5,6-tetrahydropyrimidine is dehydrogenated in the gas phase with a palladium-containing catalyst and in which a 2-propyl- or 2-butylpyrimidine is recovered from the reaction mixture, is characterized in that the gas-phase reaction is carried out using a carbon monoxide-hydrogen reactant. As this is understood a mixture of carbon monoxide and hydrogen and/or a compound capable of at least partial decomposing into CO and H.sub.2 under the reaction conditions.