Pyrimidine Derivatives; 1. The Highly Regioselective 4-Thionation of Pyrimidine-2,4(1H,3H)-dione Derivatives with Lawesson Reagent

All articles of this category 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.