- Carbanionic friedel-crafts equivalents. Regioselective directed Ortho and remote metalation-C-N cross coupling routes to acridones and dibenzo[b,f]azepinones
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(Chemical Equation Presented) Carbanion-mediated general regioselective routes to acridones 4 (Table 2) and dibenzo[b,f]azepinones 20 (Table 4) are described. Buchwald-Hartwig C-N cross coupling of o-halo benzamides 1 with anilines 2 or 16, followed by simple N-methylation, dependably provides N-methyl diarylamines 3 (Table 1) and 18 (Table 3). Upon treatment with LDA, 3 and 18 are converted into acridones 4 and dibenzo[b,f]azepinones 20, respectively, in good to excellent yields with regioselectivity which depends upon the presence or absence of directed metalation groups (DMGs). Brief investigations as follows are described: the synthesis of desmethyl acridone 15 (Scheme 4), an attempt to effect a double-directed remote metalation sequence which leads only to a monocyclization product 13 (Scheme 3), and an analogous but nonregioselective route to a xanthone 22 and dibenzo[b,f]oxepinone 24 (Scheme 5). DFT calculations reveal low energy conformations for compounds 18b and 23 which account for product formation and indicate that the cyclization reactions are under kinetic control.
- MacNeil, Stephen L.,Gray, Matthew,Gusev, Dmitry G.,Briggs, Laura E.,Snieckus, Victor
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supporting information; experimental part
p. 9710 - 9719
(2009/04/07)
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- New synthesis of oxcarbazepine via remote metalation of protected N-o-tolyl-anthranilamide derivatives
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Benzyl and allyl protected N-o-tolyl-anthranilamides were efficiently prepared by Buchwald-Hartwig C-N cross coupling reactions, followed by protection of the amino group. Under directed remote metalation conditions, protected dibenzoazepinones were obtained in good yields. Deprotection of the amine and conversion to an urea furnished a new and efficient synthesis of the antiepileptic drug Trileptal.
- Lohse, Olivier,Beutler, Ulrich,Fünfschilling, Peter,Furet, Pascal,France, Julien,Kaufmann, Daniel,Penn, Gerhard,Zaugg, Werner
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p. 385 - 389
(2007/10/03)
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