Synthesis of benzoquinoline derivatives from formyl naphthylamines via Friedländer annulation under metal-free conditions

Abstract

The synthesis of benzoquinolines and benzoquinolinones via Friedländer-type condensation of aminonaphthalene carbaldehydes with (1) primary or secondary alcohols mediated by urea/KOH or with (2) diketones or b-ketoesters is described. The behavior of naphthalene derivatives in the Friedländer annulation, resulted in the formation of Friedländer or non-Friedländer products, is also presented. Graphical abstract

Modulation of Chiroptical Properties in a Series of Helicene-like Compounds

“…A strategic role of bis-tetralone 1 as a building block in the synthesis of enantiopure dibenzo­[ c ]­acridine derivatives has been already proven. , Helicene-like structures are obtained by extending π-conjugation of the skeleton of 1 , thanks to the Friedlaender condensation of aromatic 2-amino-substituted carbonyl compounds with carbonyl derivatives containing nonsubstituted α-methylene, leading to quinolines . Few limitations for this reaction have been encountered, and a large variety of resulting quinolines containing polyaromatics has been reported. − As shown in Scheme , this reaction allowed a straightforward conversion of 1 into two new helically shaped (i.e., axially chiral) compounds 5 and 7 composed of 11 rings. Starting from 1 and 1-amino-2-naphthaldehyde 2 , two simultaneous condensations give 2,2′-dimethoxy-5,5′,6,6′-tetrahydro-1,1′-bidibenzo­[ c , h ]­acridine, 4 .…”

Synthesis of Trans‐4a,12b/3,4‐Dihydrodibenzo[f,h]quinolin‐2(1H)‐Ones and Dibenzo[f,h]quinolin‐2(1H)‐Ones via Irradiation of 6‐Biphenylpyridine‐2(1H)‐Ones

“…Zbigniew et al described the synthesis of benzoquinolin-2(1H)-ones via the Friedlander-type condensation of aminonaphthalene with diketones or β-ketoesters (Scheme 1, a). [10] Ying Cheng et al developed the Rhodium (III)catalyzed annulation of N-methoxybenzamides with 7oxa/azabenzonorbornadienes by ortho CÀ H activation to obtain benzoquinolin-2(1H)-ones (Scheme 1, b). [11] Benzoquinolin-2(1H)-ones were also obtained under solvent-free condition with the presence of TiO 2 nanopowder (Scheme 1, c).…”