Sheng-Li Hu

Efficient Selective Formation of C‐C Single Bonds and C˭C Double Bonds by NBS‐Promoted Oxidative Coupling of β‐Keto Esters

Abstract A new application of NBS, which results in the oxidative coupling of β‐keto esters to selectively form C‐C single and C˭C double bonds, can be controlled by the amount of NBS and t‐BuOK employed. This methodology adds a new entry to C‐C single and C˭C double‐bond formation between active methylene groups under mild conditions with high selectivity.

N-[(E)-4-Pyridylmethyl­ene]-4-[(E)-4-(4-pyridylmethyl­eneamino)benz­yl]aniline tetra­hydrate

The title compound, C25H20N4·4H2O, crystallizes with the organic molecule lying on a twofold rotation axis through the methylene bridge C atom; there are also two water molecules in the asymmetric unit. The crystal structure is stabilized by C—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds, linking the water molecules to each other and to the pyridine N atom.

(2RS,3SR)‐Diethyl 2,3‐bis­(1,3‐benzodioxole‐5‐carbon­yl)succinate

In the centrosymmetric title compound, C24H22O10, the two aromatic rings are parallel to each other. The crystal packing is stabilized mainly by van der Waals forces.

4-Hydroxy-2-[(4-hydroxy-1-oxo-1,2-dihydrophthalazin-2-yl)methyl]phthalazin-1(2H)-one methanol disolvate

The title compound crystallizes with the main molecule lying on a twofold axis passing through methylene atom C9 and two methanol solvent molecules in general positions. The benzene ring is coplanar with the six-membered C1/C6/C7/N1/ N2/C8 ring, making a dihedral angle of 0.62 (7) . Molecules of (I) are interlinked by the methanol molecules via O—H O and C—H O hydrogen bonds (Table 1). The methanol molecules serve as both hydrogen-bond donors and acceptors.