Imidazol-Farbstoffe VIII. Reaktion von substituierten Phthalsäureanhydriden mit 1,2-Diaminobenzol

11H-isoindolo[2,1-a]benzimidazoles (Review)

“…Thus, only the alcohol 6 was obtained during the reaction in a mixture of ether and dioxane [11,12]. Under other conditions it is possible to obtain either the same product 6 (4a:LiAlH 4 = 1:1.15, yield 76%) or the carbinolamine 63 (4a:LiAlH 4 = 1:0.77, low yield) [80]. The reduction of compound 42 (R = Ph) with lithium aluminum hydride in diethyl ether [81,82] gave an oil, which was transformed into a crystalline substance when dissolved in ethanol or chloroform.…”

“…The formation of two products is possible during the reduction of compound 4a with lithium aluminum hydride [11,12,22,79,80]. Thus, only the alcohol 6 was obtained during the reaction in a mixture of ether and dioxane [11,12].…”