| Abstract [eng] |
The cyclization reactions of initial ethyl (E)-2-cyano-3-(S-methylisothioureido)-2-propenoate under acid and basic catalysis conditions has been studied. It was determined that boiling in glacial acetic acid proceeds selectively and leads to formation of ethyl 4-amino-2-methylsulfanylpyrimidine-5-carboxylate, while ring closure in alkaline media gives rise to a mixture of 5-cyano-2-methylsulfanyl-4(3H)-pyrimidinone (major product), small amounts of ethyl 4-amino-2-methylsulfanylpyrimidine-5-carboxylate and uncyclisized products – ethyl 2-cyano-3-ureido-2-propenoates. Alkylation of 5-cyano-2-methylsulfanyl-4(3H)-pyrimidinone with 4-substituted ω- bromoacetophenones in the system CH3CN–K2CO3–[KI] has been investigated and influence of aromatic ring substituent for alkylation product distribution has been determined. The all three series of O-, N3- and N1-alkylated isomers have been isolated by means of fraction crystallization. Novel method for the synthesis of furo[2,3-d]pyrimidines by cyclization of of O-alkylated isomers – 2-methylsulfanyl-4-(4´-R-phenacyloxy)pyrimidine-5-carbonitriles – has been developed and functionalization (acetylation, oxidation, hydrolysis and hydrazinolysis) possibilities of synthesized 5-amino-6-(4´-R-benzoyl)-2-methylsulfanylfuro[2,3-d]pyrimidines has been examined. |
