Grignard Reagent Utilization Enables a Practical and Scalable Construction of 3-Substituted 5-Chloro-1,6-naphthyridin-4-one Derivatives.

A robust, practical, and scalable approach for the construction of 3-substituted 5-chloro-1,6-naphthyridin-4-one derivatives 13 via the addition of Grignard reagents to 4-amino-2-chloronicotinonitrile (15) was developed. Starting with various Grignard reagents, a wide range of 3-substituted 5-chloro-1,6-naphthyridin-4-one derivatives 13 were conveniently synthesized in moderate-to-good yields through addition-acidolysis-cyclocondensation. In addition, the robustness and applicability of this synthetic route was proven on a 100 g scale, which would enable convenient sample preparation in the preclinical development of 1,6-naphthyridin-4-one-based MET-targeting antitumor drug candidates.

Ultrafast 2,7-Naphthyridine-Based fluorescent probe for detection of thiophenol with a remarkable Stokes shift and its application In vitro and in vivo.

2,7-Naphthyridine derivatives were developed as fluorophores for the first time to design two fluorescence probes, AND-DNP and ND-DNP, which can be applied for detecting thiophenol in aqueous media. Comparing with ND-DNP, AND-DNP showed more favorable properties such as lower background, larger Stokes shift, and higher fluorescence quantum yield for detecting thiophenol. Moreover, the experimental results were verified by theoretical calculations. Hence, AND-DNP was selected as the superior fluorescence probe to detect thiophenol because of its high sensitivity and selectivity. Based on the experimental results, AND-DNP showed a remarkably larger Stokes shift (225 nm), faster response speed (30 s) and higher fluorescence enhancement (240-fold) than most other fluorescent probes for thiophenol reported in the literature. For an extended application, AND-DNP was applied to detect thiophenol quantitatively in real water samples. Meanwhile, AND-DNP also detected thiophenol via red emission in living A549 cells and zebrafish. All these results proved AND-DNP's potential value as an accurate probe for imaging thiophenol in different environments.

Phenyl substituted indenylphosphine ruthenium complexes as catalysts for dehydrogenation of alcohols.

Thermal treatment of (1H-inden-3-yl)dicyclohexylphosphinium tetrafluoroborate (1) and (3-mesityl-1H-inden-3-yl)dicyclohexylphosphinium tetrafluoroborate (3) with tBuONa followed by [(η(6)-cymene)RuCl(2))](2) in methanol gave the adduct {(η(6)-cymene)RuCl(2)[(1H-inden-3-yl)PCy(2)]} (6) and {(η(6)-cymene)RuCl(2)[(3-mesityl-1H-inden-3-yl)PCy(2)]} (7), respectively. Thermal treatment of (2-phenyl-1H-inden-3-yl)dicyclohexylphosphinium tetrafluoroborate (4) with tBuONa followed by [(η(6)-cymene)RuCl(2))](2) or RuCl(3)·3H(2)O in methanol gave {Ru[κ(P):(η(6)-2-phenyl-1H-inden-3-yl)PCy(2)]Cl(2)} (8). Whereas (2-mesityl-1H-inden-3-yl)dicyclohexylphosphine (5) reacted with [(η(6)-cymene)RuCl(2))](2) (in toluene) or RuCl(3)·3H(2)O (in ethanol) to afford {Ru[κ(P):(η(6)-2-mesityl-1H-inden-3-yl)PCy(2)]Cl(2)} (9). The molecular structures of complexes 6, 8 and 9 have been determined by single-crystal X-ray diffraction analysis. In addition, complexes 8 and 9 have been found to catalyze the acceptorless dehydrogenation of alcohols in toluene. 9 displayed high activity and different substrates, including cyclic and linear alcohols, were efficiently oxidized to ketones by using 2.0 mol% of catalyst.

Novel fluorescent molecular clips: selective recognition towards Fe3+ in aqueous solution.

In this paper, we report the synthesis, characterization and Fe(3+)-sensing properties of a series of new artificial fluorescent molecular clips, and structure of clip 1 is confirmed by X-ray crystallography. All these molecular clips had the ability to bind and sense Fe(3+) selectively through decrease fluorescence responses in THF-MeOH-Water. Fluorimetric titration experiment indicated that the quenching of these compounds' fluorescence upon Fe(3+) probably arises from the electron/energy transfer between Fe(3+) and the excited chemosensors. The limit of detection, linear concentration range and selectivity of the fluorescent molecular clips were evaluated in this study as well.

An efficient synthesis of hydantoins via sustainable integration of coupled domino processes.

A highly efficient synthesis of hydantoins has been developed from simple and commercially available 1,3-dicarbonyl compounds, ureas, and methyl ketones or terminal aryl alkenes. This protocol involves a sustainable integration of two coupled domino processes: iodine-promoted synthesis of unsymmetrical 1,4-enediones (domino I) and the sequential transformation into hydantoins (domino II).

Supramolecular rhombic grids formed from bimolecular building blocks.

A programmed assembly process produces rhombic grid networks from compounds L1-L4 in the crystal by pi-pi stacking interactions that generate a bimolecular grid synthon, which undergoes further NH...N hydrogen-bond-mediated assembly.

Diethyl 2,6-(2,4-dichloro-phen-yl)-4,8-dioxo-2,3,6,7-tetra-hydro-1H,5H-2,3a,4a,6,7a,8a-hexa-azacyclo-penta-[def]fluorene-8b,8c-dicarboxyl-ate.

The title mol-ecule, C(28)H(28)Cl(4)N(6)O(6), is built up from four fused rings, viz. two nearly planar imidazole five-membered rings which adopt envelope conformations with the C=O groups at the flap position, and two triazine six-membered rings which adopt chair conformations. Each six-membered ring has a 2,4-dichloro-benzyl substituent attached to an N atom. In the mol-ecule, the two ethyl groups are each disordered between two orientations in 0.784 (16)/0.216 (16) and 0.631 (10)/0.37 (10) ratios. Weak inter-molecular C-H⋯O hydrogen bonds help to stabilize the crystal packing.

Tetrameric molecular bowl assembled from glycoluril building blocks.

Glycoluril derivative--whose bulky Ph-C[triple bond]C- substituents prevent formation of H-bonded tapes--undergoes solvent dependent assembly in the crystal; a tetrameric molecular bowl is formed by R(24) H-bonding interactions from CH(2)Cl(2) whereas DMF results in H-bond dimerization followed by oligomerization via C-H...pi interactions.

Two-dimensional hydrogen-bonded networks in two novel glycoluril derivatives.

Two new glycoluril derivatives, namely diethyl 6-ethyl-1,4-dioxo-1,2,2a,3,4,6,7,7b-octahydro-5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate, C(14)H(21)N(5)O(6), (I), and 6-ethyl-2a,7b-diphenyl-1,2,2a,3,4,6,7,7b-octahydro-5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-1,4-dione, C(20)H(21)N(5)O(2), (II), both bearing two free syn-urea NH groups and two ureidyl C=O groups, assemble the same one-dimensional chains in the solid state running parallel to the [010] direction via N-H...O hydrogen bonds. Furthermore, the chains of (I) are linked together into two-dimensional networks via C-H...O hydrogen bonds.