Organic Communications Articles

The donor-acceptor (D - A) system, which is one of the main methods implemented in material chemistry, has been widely used to construct low band-gap semiconductors. It is desirable that donor molecules have π-conjugation in these structures. Thienothiophene (TT) derivatives have been used extensively as donors and are preferred in optoelectronic applications. As a strong acceptor, boron unit with a vacant p orbital is linked to donor TT groups. Bulky tetraphenylethylene (TPE) subunits were appended as end groups to afford an aggregation-induced emission (AIE).

Diamondoid assemblies have a potential in nanoelectronics as the substrates for self-assembled monolayer formation. However, selective functionalization of such molecules is cumbersome. We demonstrate that the McMurry cross-coupling reaction is useful for the preparation of 3-(2-adamantylidene)diamantane derivatives with substituents at the tertiary and secondary positions of the diamantane moiety. This allows to create the surface attachment points in the diamondoid structure.

A family of bisurea derivatives of 4,4′-methylenebis(phenyl isocyanate) have been synthesized with simple, effective and efficient procedure in high yields. The new compounds showed moderate bioactivity (at 32.0 µg/µL concentration) against selected bacterial pathogens, viz., Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa; and two fungal species, Candida albicans and Cryptococcus neoformans var. grubii. Alternatively, their antioxidant activity was also evaluated by DPPH radical scavenging assay which revealed that the compounds, 10d, 10e, 10h and 10m exhibited moderate activity. However, the molecular docking studies of all the title compounds showed surprisingly higher binding energies with DNA gyrase A protein of E. coli when compared to the reference, streptomycin. Among the compounds 10e, 10f, 10g, 10k,10l and 10m showed very good binding energies which implied that they could be promising next generation antimicrobials.

β-Ketoester and ethanone derivatives, potentially functional molecules, containing the pyrazole/thiazole scaffolds were synthesized. The structures of the synthesized novel compounds were confirmed by FTIR, 1H NMR and 13C NMR spectroscopy and elemental analysis. The NMR spectra of the synthesized compounds are analyzed. Furthermore, ABX systems in pyrazole ring were studied in detail and the coupling constants of the diastereotopic protons.

A facile and useful method for synthesis of benzalazines was introduced in this work. The reaction of synthesis of the relevant azines is carried out in the presence of acetonitrile-H 2O 2/(NH 4) 2CO 3 without using hydrazine. This reaction affords symmetrical azines in excellent yields with high purity. Products were characterized by the Common techniques (infrared, 1H NMR and melting point).

An unusual reaction of selective demethylation of 5-O-methylated flavones, during the reaction with semicarbazide in glacial acetic acid, is reported. The generality of the method was ascertained for various 5-O-methylated flavones. However, the method is unsuitable for chalcones, flavanones, aurones, and acetophenones. Four different flavones including heterocyclic flavone were selectively demethylated and the products were characterized by their spectral data.