Facile convergent route to indoloquinolines

Abstract

General Information: Reagents were purchased from Sigma-Aldrich and were used without further purification. IR spectra were recorded with Shimadzu FTIR instrument. 1 H & 13 C NMR spectra were recorded in DMSO-d6 with Bruker AVANCE 400 MHz NMR Spectrometer. MS were recorded with Shimadzu LCMS instrument.

A Compilation of Synthetic Strategies to Access the Most Utilized Indoloquinoline Motifs

“…These precursors were subjected to cyclization conditions using Fe/HCl in a mixture of ethanol and acetic acid (Scheme 11b). [31] Another transformation via intramolecular cyclization was reported. Isoindigos (51), prepared by condensation of isatins and indolin-2-ones, were used as the substrates.…”

“…In addition, the aldol reaction between 2‐oxoindole and ortho ‐nitrobenzaldehdye in the presence of piperidine was employed to prepare substrate 50 which was used as the important key precursors for the synthesis of indoloquinolines 1 . These precursors were subjected to cyclization conditions using Fe/HCl in a mixture of ethanol and acetic acid (Scheme 11b) [31] . Another transformation via intramolecular cyclization was reported.…”

Oxidative route to pyrroloisoquinoline-2,3-dione

“…Pyrroloquinoline-1,2-diones [5][6][7][8][9][10][11][12][13] are observed in natural compounds such as telisatin A and B, laurodionine, annonbraine, methoxylettowianthine as depicted in Figure 1. During our studies towards medicinally important organic heterocycles, [14][15][16] we encountered a route for synthesis of Pyrroloisoquinoline-2,3-dione [17][18][19] which are structurally similar to pyrroloquinoline-1,2-diones. In this paper we describe an efficient, gram scale, purification free method for synthesis of pyrroloisoquinoline-2,3-dione 1 from dihydroisoquinoline 2 through oxidative cyclisation.…”