Abstract: Pyrimidine derivatives represented by the formula, ##SPC1##Wherein R.sub.1 and R.sub.2 are individually a hydrogen atom or a methyl group, and R.sub.3 is a group formed by removing the carboxyl group from a carboxylic acid, are quite useful in acylating compounds having amino and/or imino and/or hydroxyl groups. The pyrimidine derivatives can easily be prepared by reacting a 2-mercapto-4- and/or 6-methyl-substituted or unsubstituted pyrimidine with a carboxylic acid or a reactive derivative thereof in an inert solvent.

Abstract: Thiolcarbonates represented by the formula, ##SPC1##Wherein R.sub.1 and R.sub.2 are individually a hydrogen atom or a methyl group, and R.sub.3 is a straight chain or branched chain saturated or unsaturated alkyl group having 1 to 5 carbon atoms or is a benzyl or benzhydryl group which may be nuclear substituted, are easily produced by reacting an alkali metal salt of 2-mercaptopyrimidine with phosgene, and reacting the resulting thiolchloroformate with an alcohol (R.sub.3 OH).

Abstract: Thiolcarbonates represented by the formula, ##SPC1##Wherein R.sub.1 and R.sub.2 are individually a hydrogen atom or a methyl group, and R.sub.3 is a straight chain or branched chain saturated or unsaturated alkyl group having 1 to 5 carbon atoms or is a benzyl or benzhydryl group which may be nuclear substituted, are quite useful for protecting the amino or imino groups of amines, hydrazines, amino acids and peptides with groups of the formula ##EQU1## The thiolcarbonates can be easily produced by reacting an alkali metal salt of 2-mercaptopyrimidine with phosgene, and reacting the resulting thiolchloroformate with an alcohol (R.sub.3 OH), or by reacting a 2-mercaptopyrimidine with a halocarbonic acid ester.