5-Aminothiazolium Salts as Potential Cyclic Azomethine Ylides – Base-Induced Intramolecular Cycloaddition Reactions of N-(o-Allylphenyl)- and N-(o-(Allyloxy)phenyl)-Substituted Derivatives

✍ Scribed by Georges Morel; Evelyne Marchand; Adile Touimi Benjelloun; Sourisak Sinbandhit; Olivier Guillou; Philippe Gall

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 334 KB
• Volume: 1998
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(199811)1998:11<2631::aid-ejoc2631>3.0.co;2-w

✦ Synopsis

A series of 5-aminothiazolium chlorides (1) bearing tethered cycloadducts are deduced from their spectroscopic NMR properties and unequivocally established by an X-ray benzene ring on N-3, C-4 or the exocyclic nitrogen atom are prepared by a three-component methodology and subjected diffraction analysis. Intramolecular sequence also occurs using the 2-(allyloxy)phenyl substituent on the same position to basic treatment. The initially generated mesoionic thiazoles 2 undergo internal 1,3-dipolar cycloaddition across to give a single regioisomeric 1,4-methanothiazolobenzoxazepine (7). On the contrary, hydrolysis and ring-opening the pendant olefin when the 2-allylphenyl group is connected to the endocyclic N-3. The reaction leads to the or oxidation and rearrangement of the mesoionic intermediates are the exclusive base-promoted conversions of formation of original N-bridged thiazoloquinolines as a mixture of two regioisomers 3 ,4 which are readily separated other thiazolium salts 1. by chromatography. The structural assignments of the