Direct substitution of protonated heteroarom. bases by nucleophilic carbon-centered radicals involved use of the redox system N+H3OH/Ti(III) in several solvents, use of benzoyl peroxide in alcs., and carbamoylation by HCONH2 and H2O2 in the presence of catalytic Fe(II). Thus lepidine I (R = H) in MeOH gave 98% I (R = CH2OH) in the presence of benzoyl peroxide. These systems gave hitherto unobtainable substitution products and reactions of industrial interest. Polar effects det. reactivity, selectivity and synthetic applications; in particular the role of the strongly nucleophilic intermediate radicals of pyridinyl type in the rearomatization step is emphasized
Polar effects in free-radical reactions. New synthetic developments in the functionalization of heteroaromatic bases by nucleophilic radicals
CITTERIO, ATTILIO;VISMARA, ELENA;
1985-01-01
Abstract
Direct substitution of protonated heteroarom. bases by nucleophilic carbon-centered radicals involved use of the redox system N+H3OH/Ti(III) in several solvents, use of benzoyl peroxide in alcs., and carbamoylation by HCONH2 and H2O2 in the presence of catalytic Fe(II). Thus lepidine I (R = H) in MeOH gave 98% I (R = CH2OH) in the presence of benzoyl peroxide. These systems gave hitherto unobtainable substitution products and reactions of industrial interest. Polar effects det. reactivity, selectivity and synthetic applications; in particular the role of the strongly nucleophilic intermediate radicals of pyridinyl type in the rearomatization step is emphasizedI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
