802875-94-1Relevant academic research and scientific papers
Photochemical intramolecular aromatic substitutions of the imidazol-2-yl radical are superior to those mediated by Bu3SnH
Clyne, Mairead A.,Aldabbagh, Fawaz
, p. 268 - 277 (2007/10/03)
Six-membered photochemical cyclisations of 2-iodo-N-(2-arylethyl)imidazoles proceeded regioselectively in higher yields than the equivalent tin hydride-mediated reactions. The decrease in yield of cyclisation products, 5,6-dihydroimidazo[2,1-a]isoquinolines containing strongly deactivating substituents on the aryl ring confirmed the electrophilic nature of the σ-imidazol-2-yl radicals. The seven-membered cyclisation was only successful under photochemical conditions, as radical reduction occurred with tin hydride. Nitration of 5,6-dihydroimidazo[2,1-a]isoquinoline with nitric/sulfuric acid occurred at the 2- and 8-positions. The Royal Society of Chemistry 2006.
Aromatic homolytic substitution using solid phase synthesis
Allin, Steven M.,Bowman, W. Russell,Karim, Rehana,Rahman, Shahzad S.
, p. 4306 - 4316 (2007/10/03)
Solid phase synthesis has been used to carry out intramolecular aromatic homolytic substitution with benzoimidazole precursors. The protocol attaches the radical precursors to the resins via the radical leaving groups (in the aromatic homolytic substitution). When the radical reactions are complete, the leaving group, unaltered starting material and reduced uncylised products remain attached to the resin, which facilitates easy separation of the cyclised products. Novel use of focussed microwave irradiation in solid phase radical reactions drastically shortens the reactions times. Tributylgermanium hydride has been used to replace the toxic and troublesome tributyltin hydride in the radical reactions.
