Conformational analysis of 4-(2′-furyl)-2-(methylamino)pyrimidine

Conformational transformations of the title compound 1 were studied using high-resolution ¹H-nmr techniques, semi-empirical PM3 calculations and molecular dynamics. The unfused furan-pyrimidine ring system of 1 predominantly exists in an s-trans conformation in solution and the considerable sp² character of the C2?amino bond results in the hindered rotation which is observed on the nmr time scale.