Synthesis of dihydrochromeno[4,3-b]pyrrolo[3,2-f]quinolines via intramolecular aza Diels-Alder reaction

An efficient and convenient one-pot intramolecular aza Diels-Alder approach for the synthesis of dihydrochromeno[4,3-b]pyrrolo[3,2-f]quinolines has been reported. Particularly valuable features of this methodology include simple execution, inexpensive catalyst, and good product yields.     

One-pot synthesis of furo[2,3-h]quinoline and furo[2,3-h]isoquinoline derivatives using Fischer carbene complex

A new route for the synthesis of furo[2,3-h]quinoline and furo[2,3-h]isoquinoline derivatives have been explored through the coupling of carbene complexes with pyridine-bridged enynes. This reaction process, involving the annulation of both furan and benzene ring on to a pre-existing pyridine ring is highly efficient in the presence of triphenylphosphine as ligand additive.     

Synthesis and cytotoxic activity of 2,5-disubstituted pyrimido[5,4-c]quinoline derivatives

A series of 2,5-disubstituted pyrimido[5,4-c]quinoline derivatives were synthesized and their cytotoxic activity against H460, HT-29 and MDA-MB-231 cell lines was evaluated in vitro.It was found that most of the tested compounds especially compound 17, shown stronger activity to the selected three cell lines than ZM447439.     

Quinoline-Based “On-Off” Fluorescent Sensor for Acetate: Effect of Link Mode between Binding Sites and Fluorophore on Fluorescence Changes

ABSTRACT

A novel colorimetric and fluorescence anion sensor based on 8-nitroquinolyl-2-aldehyde phenyl-thiosemicarbazone (1) was designed and synthesized according to the approach that the binding sites were covalently linked to the signaling units. In DMSO, sensor 1 exhibited a naked-eye color change from colorless to yellow upon complexation with acetate. The association constant of 1 for acetate ion was determined to be 1.20 × 10³ M^?1 by nonlinear fitting analyses of the titration curves. The strong interactions of compound 1 with acetate ion could be rationalized on basis of not only the guest basicity but also shape complementarity between 1 and acetate. In addition, the fluorescence emission of 1 was effectively quenched upon addition of acetate ions owing to the fact that the photoinduced electron transfer (PET) was enhanced.     

Trifluoromethyl group disorder in crystalline 2,8-bis(trifluoromethyl)-4-hydroxymethylquinoline

The title compound crystallized in space groupPna2₁ with lattice constantsa=13.406(1),b=18.799 (4), andc=4.785(1). The molecule is essentially flat with only fluorine atoms, methylene hydrogen atoms, and the hydroxyl hydrogen atom out of the plane of the quinoline ring. Only one of the trifluoromethyl groups of the title compound is disordered following a pattern observed in other crystal structures. Quantum chemical calculations at the AM1 level are consistent with this phenomenon. Although the carbon atom of the fixed trifluoromethyl group is further from the quinoline nitrogen atom than the carbon atom of the disordered trifluoromethyl group, the fluorine atoms of the fixed trifluoromethyl group more closely approach the quinoline nitrogen atom by 0.3 Å if the C(8)–C(10) bond in the crystal structure is freely rotated.National Research Council Associate     

Syntheses of Conjugated Polymers for Photonics

Summary: By the Suzuki coupling reaction of 9,9-dioctyl-2,7-bis(1,3,2-dioxaborinan-2-yl)fluorene ( I ) and 3,5-di-tert-butylphenyl 2,5-dibromobenzenesulfonate ( II ) the alternating poly{[9,9-dioctylfluoren-2,7-diyl]-alt-[2-(3,5-di-tert-butyl-phenoxysulfonyl)-1,4-phenylene]} ( III ) was synthesized. Alkaline hydrolysis of III gave a conjugated polyelectrolyte carrying sulfonic acid groups ( IV ). Monomers 2,5-dibromo-3-[2-(pyren-1-yl)vinyl]thiophene and 2,5-dibromo-3-[2-(quinolin-4-yl)vinyl)thiophene were prepared and copolymerized with I to afford poly{[9,9-dioctylfluoren-2,7-diyl]-alt-[3-(2-(pyren-1-yl)vinyl)thiophen-2,5-diyl]} ( V ) and poly{[9,9-dioctylfluoren-2,7-diyl]-alt-[3-(2-(quinolin-4-yl)-vinyl)thiophen-2,5-diyl] ( VI ), respectively. Conjugated backbone of V contains the conjugated pyrene unit in the side chain. Similarly the side chain of VI contains the conjugated quinoline structure unit which can be for instance protonated. By the Suzuki polycondensation reaction of I and of the prepared methyl 3-(2,7-dibromocarbazole-9-yl)propionate ( VII ) the new poly{[9,9-dioctylfluorene-2,7-diyl]-alt-[9-(2-methoxycarbonylethyl)carbazole-2,7-diyl]} ( VIII ) was synthesized and characterized.