[Omim][BF4], a green and recyclable ionic liquid medium for the one-pot chemoselective synthesis of benzoxazinones

Relating the Induced Free Charge Density Gradient in a Room-Temperature Ionic Liquid to Molecular-Scale Organization

We report on dilution-dependent changes in the local environments of chromophores incorporated into room-temperature ionic liquid (RTIL)-molecular solvent binary systems where the ionic liquid cation and molecular solvent possess the same alkyl chain length. We have used the RTIL 1-decyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (DMPyrr⁺TFSI^-) and the molecular solvent 1-decanol. Perylene was used as a non-polar probe, and cresyl violet (CV⁺) was used as a polar probe chromophore. We observe that in both regions there is a change in the chromophore local environments with increasing 1-decanol content. The changes in the nonpolar regions of the binary RTIL-molecular solvent system occur at a lower 1-decanol concentration than changes in the polar regions. Both chromophores reorient as oblate rotors in this binary system, allowing detailed information on the relative values of the Cartesian components of the rotational diffusion constants to be extracted from the experimental data. The induced free charge density gradient, ρ_f, known to exist in RTILs, persists to high 1-decanol content (1-decanol mole fraction of 0.75), with the structural details of the gradient being reflected in depth-dependent changes in the Cartesian components of the rotational diffusion constants of CV⁺. This is the first time that changes in molecular organization have been correlated with ρ_f.

Influence of Selective Extraction/Isolation of Heme/Hemoglobin with Hydrophobic Imidazolium Ionic Liquids on the Precision and Accuracy of Cotinine ELISA Test

In this study, ionic liquids were used for the selective extraction/isolation of hemoglobin from human serum for cotinine determination using the ELISA Kit. The suitability of hydrophobic imidazolium-based ionic liquids was tested, of which OMIM BF₄ (1-methyl-3-octylimidazolium tetrafluoroborate) turned out to be the most suitable for direct extraction of hemoglobin into an ionic liquid without the use of any additional reagent at one extraction step. Hemoglobin was separated quantitatively (95% recovery) from the remaining types of proteins remaining in the aqueous phase. Quantum mechanical calculations showed that the interaction of the iron atom in the heme group and the nitrogen atom of the ionic liquid cation is responsible for the transfer of hemoglobin whereas molecular dynamics simulations demonstrated that the non-covalent interactions between heme and solvent are more favorable in the case of OMIM BF₄ in comparison to water. The opposite trend was found for cotinine. Selective isolation of the heme/hemoglobin improved the ELISA test's accuracy, depending on the cotinine level, from 15% to 30%.

Synergistic promoting effect of ball milling and Fe(ii) catalysis for cross-dehydrogenative-coupling of 1,4-benzoxazinones with indoles

In this work, a novel C(sp3)–C(sp2) cross-dehydrogenative-coupling method is developed to react benzoxazin-2-one derivatives with various indoles. As a result, combined use of ball milling and Fe(ii) catalysis leads to rapid coupling of 1,4-benzoxazinones with derivatives of indole. Under the conditions, derivatives of 1 couple with various indoles at room temperature to produce good yields of the desired compounds within 0.5–2 h time period. Thus, derivatives of both starting materials couple smoothly under relatively mild conditions to give good yields of 3.

Efficient synthesis of benzene-fused 6/7-membered amides via Xphos Pd G2 catalyzed intramolecular C–N bond formation

An efficient approach for benzene-fused 6/7-membered amides via intramolecular amidation of aryl chlorides catalyzed by a Buchwald–Hartwig second generation Pd catalyst (Xphos Pd G2) has been successfully developed.

Synthesis and antifungal activity of 2H-1,4-benzoxazin-3(4H)-one derivatives

A series of 2-alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-l) was easily synthesized by two-step process involving O-alkylation of 2-nitrophenols with methyl 2-bromoalkanoates and next "green" catalytic reductive cyclization of the obtained 2-nitro ester intermediates (3a-l). Further, 6,7-dibromo (5a-c) and N-acetyl (6) derivatives were prepared by bromination and acetylation of unsubstituted 2-alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-c). The novel compounds (3a-l, 4d-l, 5a-c and 6) were fully characterized by spectroscopic methods (MS, (1)H and (13)C NMR). 2-Alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-l, 5a-c and 6) were screened for antifungal activity. Preliminary assays were performed using two methods: in vitro against seven phytopathogenic fungi-Botrytis cinerea, Phythophtora cactorum, Rhizoctonia solani, Phoma betae, Fusarium culmorum, Fusarium oxysporum and Alternaria alternata-and in vivo against barley powdery mildew Blumeria graminis. The tested compounds displayed moderate to good antifungal activity at high concentration (200 mg L(-1)). The most potent compounds were 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a), 2-ethyl-7-fluoro-2H-1,4-benzoxazin-3(4H)-one (4g) and 4-acetyl-2-ethyl-2H-1,4-benzoxazin-3(4H)-one (6), which completely inhibited the mycelial growth of seven agricultural fungi at the concentration of 200 mg L(-1) in the in vitro tests. Moreover, 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a) and 4-acetyl-2-ethyl-2H-1,4-benzoxazin-3(4H)-one (6) were also screened for antifungal activity at concentrations of 100 mg L(-1) and 20 mg L(-1). In the concentration of 100 mg L(-1), the N-acetyl derivative (6) completely inhibited the growth of three strains of fungi (F. culmorum, P. cactorum and R. solani), while 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a) completely inhibited only R. solani strain. At the concentration of 20 mg L(-1), compound 6 showed good activity only against P. cactorum strain (72%).