A second determination of the structure of hydroxyurea

Synthesis, antitumor evaluation and crystal structure of hydroxyurea derivatives

A series of hydroxyurea derivatives have been synthesized and elucidated by means of FT-IR, (1)H-, (13)C-NMR and MS. The exact stereostructures of representative compounds have been determined by X-ray crystal structure analysis. In the crystals, inversion dimers linked by pairs of N-H...O hydrogen bonds occurred, and further N-H...O links led to chains of molecules. In vitro antitumor activities against Tca8113 human tongue cancer cells and L1210 murine leukemia cells were evaluated. A total of 8 of the 12 compounds had higher inhibitory activities than hydroxyurea against L1210 cells. Among them, the most promising compounds were 3e, 3d, 3a and 2d.

1-(2-Fluorobenzyl)-1-(2-fluorobenzyloxy)urea

In the title hydroxy­urea derivative, C₁₅H₁₄F₂N₂O₂, the dihedral angle between the two benzene rings is 48.64 (19)°. The urea group forms dihedral angles of 48.1 (2) and 79.2 (2)° with the two benzene rings. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds occur, and further N—H⋯O links lead to chains of molecules.

Anomeric bond-character in the pyranose sugars

Evidence from determinations of crystal structure relating to the shortening of carbon-oxygen bonds in the anomeric position in pyranose sugars is presented. There is a high degree of probability that the C(1)-O(1) bond is shortened by about 0.04 A relative to the other C-O single-bond lengths, except in the case of an axially oriented glycosidic group where there is evidence of a distinction between the two ring C-O bonds.