Ten new 6-bromo-4-alkylthioquinazoline compounds were synthesized by the reaction of 6-bromo-4-thiolquinazoline with alkylhalide under the conditions of phase-transfer catalysis. The structures of the new compounds were characterized by 1H NMR, 13C NMR, IR spectra and elemental analyses. Bioac-tivity of the new compounds was tested. The preliminary bioassay showed that compound 6g had certain an-tifungal activities against Fusarium graminearum, Cytospora mandshurica and Fusarium oxysporum with rate of 63.8%, 51.9% and 55.1% at the concentration of 50 mg•L－1, respectively, similarly to that of control (hymexozole).

Key words: bromine, thioether, antifungal activity, quinazoline