PROBLEM TO BE SOLVED: To provide a new compound having fungicidal activity.SOLUTION: This invention relates to: thieno[2,3-d]pyrimidines of the formula (I) and a method for the control or prevention of fungal attack, including applying to the soil, plant, roots, foliage, seed or locus of the fungus, or to a locus in which the infestation is to be prevented, a fungicidal effective amount of one or more of the compounds.COPYRIGHT: (C)2012,JPO&INPIT【課題】殺真菌活性を有する新規化合物の提供。【解決手段】式(I)のチエノ[2,3-d]ピリミジン化合物、および土壌、植物、根、葉、種子、もしくは真菌の所在地に、または侵襲を予防すべき位置に、殺真菌有効量の、上記化合物の1つまたはそれ以上を散布することを含む、真菌侵襲の防除または予防方法。【選択図】なし