Reactions of pyridine N-oxide with some hydroxypirimidines in the presence of platinated palladium-carbon catalyst
The reactions of pyridine N-oxide (1) with hydroxypirimidine derivatives (2-7) in the presence of platinated palladium-carbon (Pd-Pt/C) catalyst were studied. 5-Hydroxypyrimidine (2), 4-hydroxypyrimidines (3 and 4) and 1-methyl-2-pyrimidinone (6) gave the corresponding dimers and 2-pyridyl derivatives by this condensation with high regioselectivity at the dehydrogenative position, while 2-hydroxypyrimidine (5) gave only the 2-pyridyl derivative. 2,4-Dihydroxypirimidine (7) did not react under similar reaction conditions.All the products obtained in these reactions are new compounds.These dimerization reactions may be useful for the synthesis of the dimers of N-heteroaromatic compounds.Keywores - pyridine N-oxide; hydroxypyrimidine; platinated palladium-carbon catalyst; bipyrimidine; dimer; dehydrogenative dimerization; regioselectivity.