Halocyclization of 3-Allyl-5-ethyl-6-methyl-2-thiouracil

The reaction of N-allylthiourea with ethyl 2-ethyl-3-oxobutanoate gave 3-allyl-5-ethyl-6-methyl-2- thiouracil which reacted with bromine and iodine to afford 6-ethyl-2-halomethyl-7-methyl-5-oxo-2,3-dihydro- 5H-[1,3]thiazolo[3,2-a]pyrimidinium halides. The product structure was confirmed by 1H and 13C NMR and mass spectra, elemental analyses, and X-ray diffraction data.