Photochemical Transformations of Pyridinium Salts: Mechanistic Studies and Applications in Synthesis

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Flow-Assisted Synthesis of Bicyclic Aziridines via Photochemical Transformation of Pyridinium Salts

“…11 The synthesis of a range of aminocyclopentitols by this short route is limited by the photolysis, which has been traditionally described under batch conditions. 5,7 In general, the reported photochemical transformation of pyridinium salts to bicyclic aziridines under batch conditions (Tables S1 and S2) gives low productivities of 0.0027−1.33 g L −1 h −1 (Table S1) and 0.01− 0.36 g L −1 h −1 (Table S2) using water and methanol, respectively, as the nucleophile/solvent. Consequently, only a few milligrams (less than 100 mg) of bicyclic aziridines are produced (Tables S1 and S2), which constrains the subsequent synthetic pathways.…”

“…This bicyclic aziridine can react with other nucleophiles (Nu 2 ) via S N 2 or S N 2′ pathways, providing two trisubstituted cyclopentene isomers (Scheme 1). These aziridines are versatile intermediates for the total synthesis of aminocyclopentitols 5,7 such as (+)-mannostantin A, 9 (+)-trehazolin, (−)-trehazolin, 8 and the aminocyclopentitol core of allosamidine. 11 The synthesis of a range of aminocyclopentitols by this short route is limited by the photolysis, which has been traditionally described under batch conditions.…”

Ionic Liquids: Methods of Degradation and Recovery

“…The majority of studies have looked at the photodegradation of imidazolium-based ILs. Nevertheless, there is some information on the photochemical transformations of pyridinium salts, which could be a good starting point for later IL degradation studies (Damiano et al, 2007). It seemed interesting to use the ultrasonic chemical oxidative degradation method proposed for 1,3-dialkylimidazolium ILs with different anions (chloride, bromide, hexafluorophosphate and tetrafluoroborate).…”