Oxazines have brought much synthetic interest due to their extensive biological activities. These are the important category of heterocycles, which may be formally derived from benzene and its reduction products by convenient substitution of carbon (and hydrogen) atoms by nitrogen and oxygen. In the last few decades, oxazine derivatives have documented as worthy synthetic intermediates and also blessed with notable sedative, analgesic, anticonvulsant, antipyretic, antimicrobial, antitubercular, antimalarial, antioxidant, and anticancer activities. Nowadays, it is important to develop new classes of compounds with more effective mechanisms due to drug resistance activity in which the ability of drug to effectively treat disease can be reduced. The aim of the article is to collect and make a more generalized review on the synthesis of oxazine derivatives and their pharmaceutical and biological activities. We hope this review will provide ample references for the researchers concerned with azines in generally and oxazines in particular.

Influenza virus is the main cause of an infectious disease called influenza affecting the respiratory system including the throat, nose and lungs.

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Corrosion of a material by reaction with a corrosive environment is a common problem across many industries. Iraq is an oil country and corrosion represents a large portion of the total costs for oil producing and a natural potential hazard associated with oil production and transportation. The synthesis of novel thiosemicarbazone, namely 2-(2,4-dimethoxybenzylidene)hydrazinecarbothioamide (DMBHC), was conducted and the chemical structure was elucidated via the 1H and 13C NMR (Nuclear magnetic resonance), and FT-IR (Fourier-transform infrared) spectroscopic spectroscopic techniques in addition to carbon, hydrogen, and nitrogen analyses (CHN analyses). The inhibition properties of the investigated thiosemicarbazone were evaluated for mild steel (MS) corrosion in 1N H2SO4 using electrochemical impedance spectroscopy (EIS), weight loss method, and scanning electron microscopy (SEM). Electrochemical and weight loss techniques revealed that the tested thiosemicarbazone acted as a superior inhibitor for the acidic corrosion of MS and the efficiency increased with increasing concentrations. The EIS results revealed that thiosemicarbazone demonstrated the highest inhibition efficiency of 94.86%, at a concentration of 0.5 mM. Results from the weight loss technique suggested that the thiosemicarbazone acted as a mixed type corrosion inhibitor. The impact of temperature on the mechanism of inhibition of the new synthesized inhibitor of the surface of MS in 1N H2SO4 was investigated at various temperatures (30–60 °C) where the inhibitive efficiency diminished with increasing temperatures. The mechanism of inhibition was additionally verified with the methodological data.

Starting from known p38α mitogen-activated protein kinase (MAPK) inhibitors, a series of inhibitors of the c-Jun N-terminal kinase (JNK) 3 was obtained. Altering the substitution pattern of the pyridinylimidazole scaffold proved to be effective in shifting the inhibitory activity from the original target p38α MAPK to the closely related JNK3. In particular, a significant improvement for JNK3 selectivity could be achieved by addressing the hydrophobic region I with a small methyl group. Furthermore, additional structural modifications permitted to explore structure–activity relationships. The most potent inhibitor 4-(4-methyl-2-(methylthio)-1H-imidazol-5-yl)-N-(4-morpholinophenyl)pyridin-2-amine showed an IC50 value for the JNK3 in the low triple digit nanomolar range and its binding mode was confirmed by X-ray crystallography.

The first transition‐metal‐catalyzed cross‐coupling reactions of 2,3,5‐tribromo‐1H‐inden‐1‐one are reported. The Suzuki–Miyaura reaction of 2,3,5‐tribromo‐1H‐inden‐1‐one with three equivalents of arylboronic acid gave 2,3,5‐triaryl‐1H‐inden‐1‐ones. The reaction with one and two equivalents of arylboronic acid gave 2,5‐dibromo‐3‐aryl‐1H‐inden‐1‐ones and 5‐bromo‐2,3‐diaryl‐1H‐inden‐1‐ones, respectively, with very good site‐selectivity. The one‐pot reaction of 2,3,5‐tribromo‐1H‐inden‐1‐one with one equivalent of two different arylboronic acids afforded 5‐bromo‐2,3‐diaryl‐1H‐inden‐1‐ones containing two different terminal aryl groups. Other one‐pot reactions allowed the synthesis of 2,3,5‐triaryl‐1H‐inden‐1‐ones containing different aryl groups.

Suzuki-Miyaura reactions of 2,4,5,6-tetrachloropyrimidine allow a convenient synthesis of mono-, di-, tri-and tetraarylpyrimidines which are not readily available by other methods. All reactions proceed with excellent site-selectivity.

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