78354-24-2Relevant academic research and scientific papers
Carbanionic friedel-crafts equivalents. Regioselective directed Ortho and remote metalation-C-N cross coupling routes to acridones and dibenzo[b,f]azepinones
MacNeil, Stephen L.,Gray, Matthew,Gusev, Dmitry G.,Briggs, Laura E.,Snieckus, Victor
supporting information; experimental part, p. 9710 - 9719 (2009/04/07)
(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.
An In-depth Study of the Azidobenzophenone-Anthranil-Acridone Transformation
Hawkins, David G.,Meth-Cohn, Otto
, p. 2077 - 2087 (2007/10/02)
The title transformation, particularly the conversion of anthranils into acridones, is shown to be critically sensitive to temperature, solvent, substituent, and metal catalysts.Thus the conversion of 3-(p-tolyl)anthranil into an acridone gives a ratio of 2-and 3-methyl derivatives varying from 0.6:1 to 4.7:1 with changing temperature and solvent.In other similar thermolyses, solvents (e.g. 1,2,4-trichlorobenzene) were incorporated into the product and traces of metals and their derivatives had a dramatic effect on the rate and course of the reaction.The most effective catalysts were iron powder and aluminium acetylacetonate. 3-(2,6-Disubstituted phenyl)anthranils gave acridones in which the substituents were either lost or rearranged onto N or C, the last cases involving sequential -sigmatropic shifts. 3-Thienylanthranils gave related thienoquinolones on thermolysis; again the reaction were very sensitive to catalysis.Blocked thienylanthranils also gave rearrangement products, but the non-aromatic intermediates could be isolated.
