Cytochrome P450 2A13-catalyzed alpha-hydroxylation is a critical step in the activation of the tobacco carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and (S)-N'-nitrosonornicotine [(S)-NNN]. In the enzyme's active site, a single polar residue, Asn297, can influence substrate binding, orientation, and metabolism. We determined the effects of N297A mutation on enzyme kinetics an...

In order to find a highly sensitive fluorophore, 3-azolyl-7-diethylaminocoumarin derivatives were synthesized. Both the absorption and fluorescence maxima of the coumarin-thiazole compounds showed red shifts with increases of the molar absorptivities and fluorescence intensities, in comparison with those of the corresponding coumarin-oxazole compounds. Among them, 3-(5-ethoxycarbonyl-1,3-thiazo...

The title compound, C(26)H(24)N(2)O(2), was prepared from the reaction of 4-chloro-3-formyl-coumarin with p-methyl-benzyl-amine. Even though there are no strong and specific inter-actions in the crystal structure, the translationally related mol-ecules form chains along the b axis. The coumarin moieties are stacked through π-π inter-actions [centroid-centroid distance = 3.5275 (7) Å], forming l...

The title compound, C(21)H(19)ClF(3)N(3)O(2), has a structure related to other coumarin derivatives that have been used as fluorescent probes of metal ions. The dihedral angle between the coumarin ring system and the chlorobenzene ring is 42.99 (9)°. Intra-molecular hydrogen bonding occurs via N-H⋯O and N-H⋯Cl inter-actions, generating S(7) and S(5) rings, respectively. The crystal packing is s...

In the title compound, C(17)H(13)ClO(3), the coumarin and phen-oxy moieties are essentially co-planar, making a dihedral angle of 1.99 (7)°. The phen-oxy moiety is oriented anti-periplanar with respect to the coumarin ring as indicated by the C-C-O-C angle of -179.97 (16)°. In the crystal, the sheet-like packing is stabilized by inter-molecular C-H⋯O and C-H⋯Cl hydrogen bonds.

Five new 1,3-diarylpropan-1-ols, combretol A-E (1- 5), together with one known coumarin (6) and ten known triterpenes (7-16), were isolated from Combretum yunnanense. Their structures were determined by spectroscopic investigation, including ¹H and ¹³C NMR, NOESY, HSQC, HMBC, and HRESIMS analyses. This is the first report on the occurrence of 1,3-diarylpropan-1-ols and coumarin in the Combretum...