AbstractHydroxymethyl‐benzamide and hydroxymethylphthalimide interact with uracil in the presence of concentrated sulfuric acid. Substitution takes place in the 5‐position of the uracil molecule giving derivatives of thymine namely: benzoylthyminylamine and 5‐phthalimidomethyluracil respectively.These two derivatives of thymine undergo hydrolysis with regeneration of uracil by digestion with acids.Neither of these two acylderivatives of thyminylamine can be recommended as practical intermediates for the synthesis of reduced pyrimidine derivatives related to thiamin