A variety of 2-arylbenzothiazoles were prepared by the melt reaction of 2-aminothiophenol and aryl aldehydes under oxygen atmosphere. No further oxidative reagent is needed.

Solvent-free synthesis of substituted 2-amino-4H-chromenes is described using sodium carbonate as a green and reusable catalyst. The procedure is very simple, efficient and environmentally friendly as it does not use any toxic auxiliary or solvent.

Halogenated anthraquinones can be synthesized directly from halogenated thiophenes, when these are reacted with 1,4-naphthoquinones in the presence of meta chloroperoxybenzoic acid. The halogenated anthraquinones are versatile building blocks in the preparation of arylated anthraquinones and of extended p-systems with interspersed anthraquinone units.

Ethyl 2-(diisopropoxyphosphoryl)-2H-azirine-3-carboxylate was generated “in situ” and reacted with a number of 1,3-butadienes. Cycloadducts, or in one case an ensuing rearranged product, were isolated with moderate to good yields.

A novel proton transfer compound, pyridine-2-aminium-6-methyl pyridine-2,6-dicarboxylate, has been synthesized by the reaction between 2,6-pyridinedicarboxylic acid, [pydc,H2], and 2-amino-6-methyl- pyridine, [pya], in 1:1 molar ratio under ball milling conditions. The title compound has been characterized by spectral methods (1H-, 13CNMR, IR).

The cyclocondensation reaction of N-(4-methyl-6-oxo-1,6-dihydropyrimidin-2-yl)guanidine with benzaldehyde was found to result in the formation of 2-amino-4-phenyl-4,6-dihydro-1(3)(9)H-pyrimido[1,2-a][1,3,5]triazin-6-one. The reaction proceeded chemo- and regioselectively affording the 1,3,5-triazine ring closure at nitrogen atom adjacent to carbonyl group. The structure of 2-amino-4-phenyl-4,6-dihydro-1(3)(9)H-pyrimido[1,2-a][1,3,5]triazin-6-one was supported by 1H,13C NMR and 2D NOESY spectral data. From the experimental data, 3H- tautomeric form seemed to be predominant in DMSO-d6 solution. The relative energies of the tautomers were estimated using calculations at different levels of theory (HF/6-311G**, B3LYP/6-311++G** and MP2/6-311++G**). Both the experimental and theoretical results excluded 6-hydroxy tautomer from the equilibrium. 2-Amino-4-phenyl-4,6-dihydro-1H-pyrimido[1,2-a][1,3,5]triazin-6-one was calculated to be the energetically preferred tautomeric form in gas phase.

The hexadentate Schiff base ligands were prepared by condensation of 3-ethoxy-2-hydroxybenzaldehyde and different diamines (1,3-diaminopropane, 1,3-diamino-2,2-dimethylpropane, 1,4-diaminobutane) to yield H2Ln (H2L1, H2L2 and H2L3, respectively). The ligands have been characterised by elemental analysis, IR, 1H and 13C NMR spectroscopies and mass spectrometry (ES). The crystal structure of the H2L2 ligand was solved by X-ray crystallography, revealing its ability to bind metal centres.

Amide group reduction in monosaccharide derivative 2,3-epoxyamides were accomplished with a combination of two reagents: RedAl and NaBH4, successively added at 0ºC, without affecting the epoxide group. The obtained epoxyalcohols could be regioselectively opened at the vicinal carbon to the hydroxymethyl group, by NaN3/Me3B without detection of another azido isomer.

A new class of flavone which possess an aryl radical substituted in the A ring via C-C bond, arylchrysin analogues, has been synthesized from chrysin by Suzuki coupling reaction in three to five steps. Firstly, methylation or benzylation reaction was applied on chrysin to protect hydroxyl phenol moiety. Then, halogenation by iodine or bromine in anhydrous acetic acid was performed to obtain halogenated chrysin. Finally, intermediate compounds were treated with areneboronic derivatives catalyzed by palladium tetrakits to generate arylchrysin analogues with high yields.

An efficient one-pot synthesis of methyl-N-[2-(6-oxo-3-p-tolyl-5,6-dihydro-4Hpyridazin-1-yl)-acetamide]alkanoates 5a-j and dipeptides 8a-f was successfully realized starting from amino acid esters 4 and azides 3, 7, respectively. The hydrazide 6a was further reacted with selected aldehydes to give the corresponding hydrazones 9a-c.