Synthesis, Characterization And Crystal Analysis Of Several2-Thiouracil Derivatives

Pyrimidine derivatives have wide occurrence in nature, some of which areimportant structural components in biological molecules DNA and RNA carrying thegenetic information and participate in activities of life in the body.2-Thiouracil, oneof the pyrimidine derivatives, has shown a variety of biological activities due to itsunique structure. Its derivatives have been widely used in medicine, pesticide andchemical fields.In this dissertation, the synthetic methods of2-thiouracil derivatives and theirapplications in the fields of medicine and supramolecular chemistry were brieflyreviewed. Then, a study on the selective alkylation of5,6-trimethylene-2-thiouracilwas carried out. The main results are as follows:1. A new method, in which CTAB, K2CO3and butanone were used as phase transfercatalyst (PTC), base and solvent, respectively, has been developed for selectivesynthesis of S-alkylated derivatives of5,6-trimethylene-2-thiouracil in excellentyields.2. Continued O-or N-alkylation of S-alkylated2-thiouracil derivatives was carriedout, giving a higher yield of S,N3-dialkylated product than that of S,O-dialkylatedone by using a PTC process, however, giving a reverse result by using a PTC-freeprocess.3. A similar dialkylation ratio was obtained by the more simple one-pot reactionusing5,6-trimethylene-2-thiouracil as starting material. For example, also a higheryield of S, N3-dialkylated product was given by using the PTC process.4. A total of sixteen2-thiouracil derivatives, of which thirteen are new compounds,were successfully synthesized and fully characterized by IR,1H NMR,13C NMRand HR-MS spectroscopies, as well as for five2-thiouracil derivative beingdetermined by X-ray diffraction techniques.5. Five2-thiouracil derivatives display a combination of N H O, N H S, C H O,C H N and C H F hydrogen bonds, which is significant in the development oflipoprotein-associated phospholipase A2inhibitors.