PROBLEM TO BE SOLVED: To provide an agent for amplifying hematopoietic stem cells and/or hematopoietic precursor cells, which is useful in a therapeutic method for various types of hematopoietic system diseases and also useful in improving efficiency of gene transfer to hematopoietic stem cells at the time of a gene therapy.SOLUTION: A method for producing hematopoietic stem cells and/or hematopoietic precursor cells comprises cultivating and amplifying the hematopoietic stem cells in the presence of at least one of compounds represented by formula (1) (Rto Rand Y in the formula are as defined in the specification), at least one of tautomers of them, at least one of pharmaceutically acceptable salts of the compounds, or at least one of solvates of the compounds.【課題】 各種の造血系疾患に対する治療方法として有用であり、遺伝子治療時の造血幹細胞への遺伝子導入効率の向上に有用である、造血幹細胞及び／又は造血前駆細胞の増幅剤を提供する。【解決の手段】 下記式（１）（式中のＲ１～Ｒ３、Ｙは、本文中において定義される。）で表される化合物、該化合物の互変異性体、それらの医薬的に許容され得る塩又はそれら化合物の溶媒和物の存在下、造血幹細胞を培養して増幅させることを特徴とする造血幹細胞及び／又は造血前駆細胞の製造方法。【化１】【選択図】なし
