ABSTRACT
Synthesis and chelation induced fluorescence emission from two imidazo[1,2-a]pyridine derivatives are described. The nonfluorescent molecule 1 containing N and O donor atoms, achieves coplanarity upon interactions with trivalent cations Al3+, Fe3+ and Cr3+, that favors fluorescence emission. Molecule 2 containing two N donor atoms attains coplanarity upon interaction with the only Zn2+ and becomes fluorescent. Both molecules 1 and 2 form a 1:1 complex with interacting metal ions. Other trivalent metal ions (including Bi3+ and In3+) and common divalent metal ions (including Hg2+ and Cd2+) fail to form any complex with 1 or 2, and they do not interfere in the detection of Zn2+, Al3+, Fe3+ or Cr3+ ions. Noninterference of other metal ions renders 1 and 2 suitable for the detection of fungal cells contaminated with Zn2+, Al3+, Fe3+ or Cr3+ ions.
Subject(s)
Chelating Agents/chemistry , Fluorescent Dyes/chemistry , Metals/analysis , Pyridines/chemistry , Cations/analysis , Microscopy, Fluorescence/methods , Models, Molecular , Optical Imaging/methods , Rhizoctonia/chemistry , Rhizoctonia/cytology , Spectrometry, Fluorescence/methodsABSTRACT
An unprecedented tandem oxidation/Michael/aldol reaction is reported. The diastereoselective formation of only a single isomer of dispirocyclopentanebisoxindole and dispiro[acenaphthylene-1,1'-cyclopentane-3',1''-acenaphthylene]-2,2''dione is presented. The reaction generates two new C-C bonds and two all-carbon quaternary chiral stereocenters in a single step.
ABSTRACT
A Lewis acid catalyzed domino reaction cascades through azide-alkene cycloaddition, rearrangement, aziridine ring opening, and azomethine cycloaddition with a parent dipolarophile, resulting in 3,3'-pyrrolidinyldispirooxindoles containing four contiguous chiral stereocenters with two contiguous quaternary spirostereocenters.
