Thiocyanation in the 5-position occurs readily with pyrimidines bearing at least two hydroxyl or amino groups in positions 2, 4 and 6. An alternate synthesis of thiazold 4, 5-d] pyrimidines bearing non-functional substituents in the 2-and 4-position also was developed. In the latter method a 4-thiocyanopyrimidine is formed by the reaction of a 4-ehloropyrimidine with potassium thiocyanate and after isomerization is eventually converted to a ...