Studies On Synthetic Methods Using KF/Al₂O₃ Catalyst, Chemical Properties And Biological Activities Of Polysubstituted Pyrimidines

The KF/Al2O3 catalyst, which mainly be applied to alkylations of C, N, O, S and some condensation reactions of straight chain carbon compounds, was first used to catalyze the synthesis of polysubstituted pyrimidines from [bis(methylthio)methylene]propanedinitrile (1a) with isothiuronium salts. Six 2-alkylthio-4-amino-5-cyano-6-methylthio- pyrimidines (3) were obtained in the average yield of 77.7% under solvent acetonitrile and the catalyst amount 1.5g/(5mmol 1a). It was found that 3 could be synthesized with "one-step reaction" and "dry reaction". When [bis(alkyllthio)methylene]propanedinitrile reacted with thiourea in the present of KF/Al2O3, the products were 2,6-dialkylthiopyrimidines instead of 2-mercapto-6-alkylthio- pyrimidines.The chemical properties of compounds 3 were investigated. We found the alkylthio group could be substituted by morpholine and alkoxide. For morpholine, the product was single substituted and disubstituted for alkoxide. The amino group could be single alkylated with KF/Al2O3 catalyst. The highest yield reached to 96% when amino group was acetylated with acetic anhydride.19 novel polysubstituted pyrimidines were obtained and all the structures were confirmed by 1H NMR, IR and MS.Some also confirmed by elemental analysis. The medicinal and pesticidal activities of five compounds were measured. They revealed high herbicidal activities under the condition of measurement.One C60-polysubstituted pyrimidine derivative also was synthesized and basically confirmed for its structure by MS, 1H NMR and IR. The hydrolysis product of 1a was firstly found and the structure was also confirmed.