Enhancing local-scale groundwater quality predictions using advanced machine learning approaches.

Assessing groundwater quality typically involves labor-intensive, time-consuming, and costly laboratory tests, making real-time monitoring impractical, especially at the local level. Groundwater quality projections at the local scale using broad spatial datasets have been inaccurate due to variations in hydrogeology, human activities, industrial operations, groundwater extraction, and waste disposal. This study aims to identify the most dependable and resilient machine learning algorithms for forecasting groundwater quality at nearby monitoring locations by utilizing simple water quality metrics that can be quickly assessed without extensive sampling and laboratory testing.

Organoselenium and DMAP co-catalysis: regioselective synthesis of medium-sized halolactones and bromooxepanes from unactivated alkenes.

A catalytic system consisting of bis(4-methoxyphenyl)selenide and 4-(dimethylamino)pyridine (DMAP) has been developed for the regioselective synthesis of medium-sized bromo/iodo lactones and bromooxepanes possessing high transannular strain. (77)Se NMR, mass spectrometry and theoretical studies reveal that the reaction proceeds via a quaternary selenium intermediate.

Synthesis and structural characterization of monomeric mercury(II) selenolate complexes derived from 2-phenylbenzamide ligands.

Monomeric Hg(II) selenolate complexes derived from 2-phenylbenzamide ligands were prepared by oxidative addition of diselenides [{C6H4(CONR2)Se}2, R = Me, Et, iPr] to elemental Hg and reductive cleavage of the Se–N bond of isoselenazolone derivatives [(NO2)C6H3(CONSe)R, (R = allyl, nbutyl)] followed by the treatment with HgCl2. The complexes have been characterized by multinuclear NMR (1H, 13C and 77Se) spectroscopy and mass spectrometry which suggest the monomeric form of these in solution. The molecular structures of diselenides [C6H4(CONR2)Se]2 and mercury selenolates [Hg{(NO2)C6H3(CONH-C3H5) Se}2], [Hg{C6H4(CONiPr2)Se}2] and [Hg{C6H4(CONMe2)Se}2] were established by a single crystal X-ray diffraction study.

KO(t)Bu-mediated annulation of acetonitrile with aldehyde: synthesis of substituted dihydropyridin-2(1H)-ones, pyridin-2(1H)-ones, and thiopyridin-2(1H)-ones.

The KO(t)Bu-mediated annulation of acetonitrile with aldehyde was observed, in which the cleavage of four C(sp(3))-H bonds occurred and a total of eight new bonds were formed during the synthesis of substituted dihydropyridinones in the presence of peroxide. Furthermore, dihydropyridinones have been transformed into pyridinones using KO(t)Bu in DMSO.

KO(t)Bu-mediated aerobic transition-metal-free regioselective β-arylation of indoles: synthesis of β-(2-/4-nitroaryl)-indoles.

A KO(t)Bu-mediated intermolecular oxidative C-C coupling of nitroarenes with indoles is presented in DMSO at room temperature in an open flask. By using this mild and economical methodology, syntheses of β-(2/4-nitroaryl)-indoles with sensitive functionalities such as bromo, iodo, cyano, and nitro were achieved chemo- and regioselectively. Synthesized β-(2/4-nitroaryl) indoles were transformed into densely functionalized biindoles, indoloindoles, and (4-aminoaryl)-indoles which demonstrate post-transformation utility of the developed methodology.

Transition metal free intramolecular selective oxidative C(sp3)-N coupling: synthesis of N-aryl-isoindolinones from 2-alkylbenzamides.

A synthetic method has been developed for the preparation of biologically important isoindolinones including indoprofen and DWP205190 drugs from 2-alkylbenzamide substrates by transition metal-free intramolecular selective oxidative coupling of C(sp(3))-H and N-H bonds utilizing iodine, potassium carbonate and di-tert-butyl peroxide in acetonitrile at 110-140 °C.

Chemoselective arylation of phenols with bromo-nitroarenes: synthesis of nitro-biaryl-ols and their conversion into benzofurans and carbazoles.

A series of electron withdrawing or donating group substituted phenols were chemoselectively arylated with various substituted bromo-nitroarenes using KO(t)Bu at room temperature via an SNAr pathway. The synthesis of natural alkaloids (carbazoles), dibenzofurans, and a biaryl-indole was achieved from the synthesized nitro-biaryl-ols.

KO(t)Bu-mediated synthesis of dimethylisoindolin-1-ones and dimethyl-5-phenylisoindolin-1-ones: selective C-C coupling of an unreactive tertiary sp3 C-H bond.

A new reaction for the synthesis of dimethylisoindolinones has been presented from 2-halo-N-isopropyl-N-alkylbenzamide substrates and KO(t)Bu by the selective C-C coupling of an unreactive tertiary sp(3) C-H bond. The reaction manifested an excellent selectivity toward a tertiary sp(3) C-H bond over primary or sec C-H bond. Moreover, biaryl C-C coupling along with alkyl-aryl C-C coupling can be achieved in one pot using dihalobenzamides for the synthesis of biaryl 5-phenylisoindolin-1-ones.