Utilizing 2,4-bis(4-methoxyphenyl)-2,4-dithioxo-1,3,2,4-dithiadiphosphetane (Lawesson reagent), the 4-oxo group of pyrimidine bases such as 5-fluorouracil, uracil, and thymine were selectively converted into the corresponding 4-thioxo analogous. 2-Thiouracil was similarly transformed into 2,4-dithiouracil, but 4-thiouracil remains almost intact.
利用2,4-bis(4-methoxyphenyl)-2,4-dithioxo-1,3,2,4-dithiadiphosphetane(Lawesson试剂),选择性地将5-
氟尿
嘧啶、尿
嘧啶和胸腺
嘧啶等
嘧啶碱基的4-氧基转化为相应的4-
硫代类似物。2-
硫尿
嘧啶也被转化为2,4-二
硫尿
嘧啶,但4-
硫尿
嘧啶几乎保持不变。