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Communication | Regular issue | Vol 19, No. 11, 1982, pp.2061-2066
Published online, 1st January, 1970
DOI: 10.3987/R-1982-11-2061
Ring-Transformation of 1,2,4-Oxadiazine Derivatives into 4-Hydroxypyrimidine Derivatives: Catalytic Hydrogenation of 3-Aryl-5-ethoxycarbonylmethelene-5,6-dihydro-4H-1,2,4-oxadiazine Derivatives

Katsumi Tabei, Estuko Kawashima, Toyozo Takada, and Tetsuzo Kato

*Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan


Catalytic hydrogenation of 3-aryl-5-ethoxycarbonylmethylene-5,6-dihydro-4H-1,2,4-oxadiazine derivatives (1) is described. The method leads to new synthesis of 2-aryl-4-hydroxypyrimidine derivatives (3) involving cyclization of ethyl 3-benzimidoylimino-4-hydroxybutanoate derivatives (2) by the elimination of ethanol. Nickel catalyzed hydrogenation of 1 gave ethyl 2-aryl-4-oxazolylacetate (4) as a by-product besides product 3.