A Bioinspired Synthesis of Polyfunctional Indoles.

Polyfunctional indoles bearing substituents at C5 and C6 are prevalent in natural products, pharmaceuticals, agrochemicals, and materials. Owing to the remoteness of the C5 and C6 positions, indoles of this family can be difficult to prepare, and often require multistep syntheses. Herein, we describe a concise process that converts simple derivatives of tyrosine into 5,6-difunctionalized indoles by direct oxidation of C-H, N-H, and O-H bonds.

Theoretical approaches for predicting the color of rigid dyes in solution.

Aiming at developing an affordable and easily implementable computational protocol for routine prediction of spectral properties of rigid molecular dyes, density functional theory, and time-dependent density functional theory were used in conjunction with a vibronic coupling scheme for band shape estimate. To predict the perceived color of molecules in solution, a model has been setup linking the UV-vis spectra predicted at ab initio level to the L*a*b* colorimetric parameters. The results show that a mixed protocol, implying the use of a global hybrid functional for the prediction of adiabatic energy differences and a range separated hybrid for the prediction of potential energy curvature, allows perceived colors to be quantitatively predicted, as demonstrated by the comparison of L*a*b* colorimetric parameters obtained from computed and experimental spectra.

Conformational equilibria and barriers to rotation in some novel nitroso derivatives of indolizines and 3- and 5-azaindolizines - an NMR and molecular modeling study.

Conformational equilibria in novel C-nitroso derivatives of indolizines and 3- and 5-azaindolizines have been studied by NMR. (13)C chemical shifts of the carbon alpha to the nitroso group confirmed that these compounds are present in solution as monomers. The conformers arising from restricted rotation about the C-NO bond in monomers were identified by the chemical shifts of the carbon beta to the nitroso group.

1H, 13C, and 15N NMR spectra of some pyridazine derivatives.

(1)H, (13)C, and (15)N NMR chemical shifts for pyridazines 4-22 were measured using 1D and 2D NMR spectroscopic methods including (1)H-(1)H gDQCOSY, (1)H-(13)C gHMQC, (1)H-(13)C gHMBC, and (1)H-(15)N CIGAR-HMBC experiments.