6-AMINOURACIL-2-THIONE (1) and its 5-bromo derivative 2 underwent alkylation yielding their respective S-alkyl products 4_a-j. The reaction of compound 1 and aldehydes in the presence of chloroacetic acid afforded the respective thiazolopyrimidinyl acetamides 7_a-d. The C-glycosides 8_a,b and 9_c-e were successfully prepared through condensing compound 1 and the appropriate sugar in the presence of chloroacetic acid. The behavior of certain S-alkyl derivative 4 towards amines and hydrazines was also studied. Structure elucidations for the new products were supported by compatible chemical and spectral measurements.