Two nitrogen atoms containing heterocyclic compounds or diazines, pyridazines, pyrimidines and piperazines are important structural feature of many biologically active compounds and show diverse pharmacological properties. These diazines hold considerable interest in the preparation of organic intermediates and physiologically active compounds. Diazines focus our attention because of their easy...

The vaporization enthalpies and liquid vapor pressures of quinoxaline, quinazoline, phthalazine, benzo[c]cinnoline, 1,10-phenanthroline, phenazine, and triphenylamine are measured by correlation-gas chromatography and compared to values calculated from available literature vaporization, sublimation, and fusion enthalpy data. Good agreement with the literature is observed for all compounds excep...

The vaporization enthalpies of 1-methyl-, 1-ethyl-, 1-phenyl-, and 1-benzylimidazole, 1-methyl- and 1-phenylpyrazole, and trans-azobenzene are evaluated by correlation-gas chromatography (C-GC) using a variety of azines and diazines as standards. The vaporization enthalpies obtained by C-GC when compared to literature values are approximately 14 kJ·mol(-1) smaller for the imidazoles and 6 kJ·mo...

Copper(I) and nickel(0) complexes catalyze the formal [4 + 2] cycloaddition reactions of 1,2-diazines and siloxyalkynes, a reaction hitherto best catalyzed by silver salts. These catalysts based on earth abundant metals are not only competent, but the copper catalyst, in particular, promotes cycloadditions of pyrido[2,3-d]pyridazine and pyrido[3,4-d]pyridazine, enabling a new synthesis of quino...

This critical review targets as a readership researchers generally oriented toward organic synthesis and in particular those active in heterocyclic chemistry. Diazines and benzo derivatives can undergo deprotonative metalation provided that the base is properly chosen. Metalation reactions of a large range of substrates can be performed using hindered lithium dialkylamides such as lithium 2,2,6...

Ion-molecular reactions of nucleogenic phenyl cations with the nucleophilic centers of 1,4-diazines have been investigated for the first time. Previously unknown tritium labeled N-phenyl quaternary derivatives of pyrazine and quinoxaline, which are potential radioactive biomarkers, have been obtained by nuclear-chemical method.

An efficient iodine-mediated oxidative annulation of aryl acetylenes-arylethenes-aromatic ketones with 1,2-diamines for the synthesis of pyrazines and regioselective synthesis of quinoxalines is presented. A multipathway coupled domino approach has been developed for the one-pot synthesis of 1,4-diazines with high functional group compatibility.

This study establishes a new trans-metal-trapping (TMT) procedure based on a mixture of LiTMP (the base) and tris(trimethylsilylmethyl)gallium [Ga(CH2 SiMe3 )3 , GaR3 ] (the trap) that, operating in a tandem manner, is effective for the regioselective deprotonation of sensitive diazines in hydrocarbon solution, as illustrated through reactions of pyrazine, pyridazine, and pyrimidine, as well as...