Furo[3,2-b]pyridine: a convenient unit for the synthesis of polyheterocycles

Investigation of Solvent Effect and H-Bonding on Spectroscopic Properties of 1-(3-Amino-6-(2,5-dichlorothiophen-3-yl)-4-phenylfuro[2,3-b]Pyridin-2-yl) Ethenone: Experimental and Computational Study

The furo[2,3-b]pyridine moiety is an important scaffold for many biologically active compounds, therefore, the spectral data of the derivative 1-(3-Amino-6-(2,5-dichlorothiophen-3-yl)-4-phenylfuro[2,3-b]pyridin-2-yl) ethenone (FP1) were investigated. Analysis of absorption-pH profile and Förster cycle of FP1 revealed that its excited state is more acidic than its ground state ([Formula: see text] < [Formula: see text]). The main fluorescence emission band of FP1 at 480 nm (in hexane) is shifted to longer wavelengths with increasing polarities of solvents. Linear Lippert's plot and linear correlation between bands maxima and Camlet-Taft parameter, α, of the protic solvents indicated efficient intramolecular charge transfer and noticeable H-bonding. Moreover, the disappearance of the absorption band of FP1 at 385 nm in water, along with the noticeable red shift and quenching of the emission band, and the lower lifetime, relative to nonaqueous solvents, indicate the interruption of the furo[2,3-b]pyridine aromatic moiety. In addition, results from the Time Dependent Density Functional Theory (TDDFT) and Molecular Mechanic (MM) calculations were in agreement with experimentally determined spectra of FP1.

Furo[3,2-b]pyridine: A Privileged Scaffold for Highly Selective Kinase Inhibitors and Effective Modulators of the Hedgehog Pathway

Reported is the identification of the furo[3,2-b]pyridine core as a novel scaffold for potent and highly selective inhibitors of cdc-like kinases (CLKs) and efficient modulators of the Hedgehog signaling pathway. Initially, a diverse target compound set was prepared by synthetic sequences based on chemoselective metal-mediated couplings, including assembly of the furo[3,2-b]pyridine scaffold by copper-mediated oxidative cyclization. Optimization of the subseries containing 3,5-disubstituted furo[3,2-b]pyridines afforded potent, cell-active, and highly selective inhibitors of CLKs. Profiling of the kinase-inactive subset of 3,5,7-trisubstituted furo[3,2-b]pyridines revealed sub-micromolar modulators of the Hedgehog pathway.

Rational Improvement of Molar Absorptivity Guided by Oscillator Strength: A Case Study with Furoindolizine-Based Core Skeleton

The rational improvement of photophysical properties can be highly valuable for the discovery of novel organic fluorophores. Using our new design strategy guided by the oscillator strength, we developed a series of full-color-tunable furoindolizine analogs with improved molar absorptivity through the fusion of a furan ring into the indolizine-based Seoul fluorophore. The excellent correlation between the computable values (oscillator strength and theoretical S0 -S1 energy gap) and photophysical properties (molar absorptivity and emission wavelength) confirmed the effectualness of our design strategy.

A novel one-pot method for the synthesis of substituted furopyridines: iodine-mediated oxidation of enaminones by tandem metal-free cyclization

A novel iodine-mediated oxidative tandem cyclization reaction of simple enaminones has been developed for the synthesis of substituted furopyridines through C–C/C–N/C–O bond formation in a one-pot procedure.

C7-derivatization of C3-alkylindoles including tryptophans and tryptamines

A versatile strategy for C7-selective boronation of tryptophans, tryptamines, and 3-alkylindoles by way of a single-pot C2/C7-diboronation-C2-protodeboronation sequence is described. The combination of a mild iridium-catalyzed C2/C7-diboronation followed by an in situ palladium-catalyzed C2-protodeboronation allows efficient entry to valuable C7-boroindoles that enable further C7-derivatization. The versatility of the chemistry is highlighted by the gram-scale synthesis of C7-boronated N-Boc-L-tryptophan methyl ester and the rapid synthesis of C7-halo, C7-hydroxy, and C7-aryl tryptophan derivatives.