A green procedure for the synthesis of 1,8‐dioxo‐decahydroacridine derivatives is developed under microwave irradiation without catalyst in water. This method provides several advantages such as excellent yields (86–96%), simple workup procedure, and environment friendliness. J. Heterocyclic Chem., (2010).

Key indicators: single-crystal X-ray study; T = 298 K; mean (C-C) = 0.005 Å; R factor = 0.052; wR factor = 0.152; data-to-parameter ratio = 15.0.The title compound, C 30 H 32 FNO 2 , was synthesized by the reaction of dimedone with 4-fluorobenzaldehyde and ptoluidine in water. The dihydropyridine and both of the cyclohexenone rings are not planar and have flattened boat conformations. The dihedral angle between the planar aromatic rings is 15.33 (3) . In the crystal structure, intermolecular C-HÁ Á ÁO hydrogen bonds link the molecules into centrosymmetric dimers. Related literature

Co 2+ -doped MgGa 2 O 4 nanocrystals were prepared at 500°C by a low-temperature combustion method without any further calcination. Powder X-ray diffraction (XRD) indicated that the only crystalline phase in the product was MgGa 2 O 4 with a grain size of 33-36 nm. Scanning electron microscopy (SEM) showed that the products contained pores formed by the gases evolved during the combustion reaction. The excitation and emission spectra of the nanocrystalline powders in the visible and near infrared regions were characteristic of tetrahedral Co 2+ ions, suggesting that Co 2+ ions replaced tetrahedral Mg 2+ ions in the MgGa 2 O 4 crystals. We assigned the visible and near infrared luminescent bands to the spin-allowed 4 T 1 ( 4 P) ® 4 A 2 ( 4 F) and 4 T 1 ( 4 P) ® 4 T 2 ( 4 F) transitions.

The reaction tolerates a wide variety of differently substituted aldehydes and arylamines.