NEW METHOD FOR THE SYNTHESIS OF THIENO[2,3-<i>d</i>]PYRIMIDINES
DOI:
https://doi.org/10.1007/s10593-005-0082-yKeywords:
isothiazolo[5,4-d]pyrimidine, nitromethane, thieno[2,3-d]pyrimidine, 5-formylpyrimidineAbstract
The reaction of 5-formyl-4-thiocyanatopyrimidines with nitromethane was studied under various conditions. The reaction was found unexpectedly to proceed with closure of a thiophene ring to give thieno[2,3-d]pyrimidines. The use of ammonium acetate as the catalyst leads to a side reaction involving closure of an isothiazole ring to give isothiazolo[5,4-d]pyrimidines. X-ray diffraction crystallographic analysis was used to confirm the structure of thieno[2,3-d]pyrimidine.