A series of thiazolo[5,4-d]pyrimidine derivatives were synthesized and evaluated for their antiproliferative activities against several human cancer cell lines. Structure–activity relationship studies were carried out, showing that most of the target compounds had good inhibition against the tested cell lines. Among them, compound 7i exhibited potent inhibition against human gastric cancer cells MGC-803 and HGC-27 with IC₅₀ values of 4.64 and 5.07 μM, respectively and around 12-fold selectivity between MGC-803 and GES-1, indicating a relatively low toxicity to normal cells. The potency and low toxicity of compound 7i make the thiazolo[5,4-d]pyrimidine an attractive scaffold for designing new derivatives selectively targeting MGC-803 cells.

中文翻译：

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新的噻唑并[5,4- d ]嘧啶衍生物作为有效抗增殖剂的设计，合成及生物学评价

合成了一系列噻唑并[5,4- d ]嘧啶衍生物，并评估了其对几种人类癌细胞系的抗增殖活性。进行了结构-活性关系研究，结果表明大多数目标化合物对受试细胞系均具有良好的抑制作用。其中，化合物7i对人胃癌细胞MGC-803和HGC-27表现出强抑制作用，IC ₅₀值分别为4.64和5.07μM，在MGC-803和GES-1之间的选择性约为12倍，表明相对较低对正常细胞有毒性。化合物7i的效力和低毒性使噻唑洛[5,4- d]嘧啶是一种有吸引力的支架，用于设计选择性靶向MGC-803细胞的新衍生物。