Crystal structure of 5-benzoylamino-5-isopropyl-4-oxo-1,3-dioxane

C₁₄H₁₇NO₄ crystallizes in the monoclinic space groupP2₁/n (Z=4) witha=10.208(2),b=10.888(2),c=11.909(2) Å, and=90.89(2)°. The structure was solved by direct methods and refined by full-matrix LSQ to anR factor of 0.036. The 4-oxo-1,3-dioxane ring is in a slightly distorted O(1)-sofa conformation flattened at the C(4) end with the 5-isopropyl substituent in a pseudoaxial position and planar lactone group. The molecules form dimers by means of intermolecular N-HO(4) hydrogen bonds of 3.091(2) Å. The¹H NMR spectrum of the title compound shows unusual features.