ISSN:
1434-193X
Keywords:
Isocyanides
;
Mesoionic compounds
;
Azomethine ylides
;
Cycloadditions
;
Polyheterocycles
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A series of 5-aminothiazolium chlorides (1) bearing tethered benzene ring on N-3, C-4 or the exocyclic nitrogen atom are prepared by a three-component methodology and subjected to basic treatment. The initially generated mesoionic thiazoles 2 undergo internal 1,3-dipolar cycloaddition across the pendant olefin when the 2-allylphenyl group is connected to the endocyclic N-3. The reaction leads to the formation of original N-bridged thiazoloquinolines as a mixture of two regioisomers 3,4 which are readily separated by chromatography. The structural assignments of the cycloadducts are deduced from their spectroscopic NMR properties and unequivocally established by an X-ray diffraction analysis. Intramolecular sequence also occurs using the 2-(allyloxy)phenyl substituent on the same position to give a single regioisomeric 1,4-methanothiazolobenzoxazepine (7). On the contrary, hydrolysis and ring-opening or oxidation and rearrangement of the mesoionic intermediates are the exclusive base-promoted conversions of other thiazolium salts 1.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
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