Some 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐i,j]quinolines

Abstract

On the basis of structural features which relate 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐i,j]quinolines to indoles, several representative groups of derivatives were synthesized.

A new synthetic route to pyrroloquinolines and pyrroloindoles

“…Microanalyses were performed on Carlo Erba Elemental Analyser EA 1108 at the Campbell Microanalytical Laboratory, Univeristy of Otago, New Zealand. 1 H and 13 C NMR spectra were obtained on a Bruker DPX300 (300 MHz) spectrometer. Mass spectra were recorded on either a Bruker Daltonics Bio Apex II FTICR MS (HRMS-ESI) at School of Chemistry, University of New South Wales, or a Shimadzu LCMS QP 8000 (EI) at the University of Otago, New Zealand.…”

“…UV/Vis (λmax, nm, ε, cm -1 M -1 ): 237 (24,000), 271 (19,000), 400 (14,100). 1 Dimethyl 9-methyl-6,8-dimethoxy-3H-pyrrolo[1,2-a]indole-2,3-dicarboxylate (4a). To a cooled (0-5 ˚C) mixture of indole-2-carbaldehyde 3a 20 (50 mg, 0.228 mmol) and triphenylphosphine (66 mg, 0.251 mmol) in dry dichloromethane (4.5 mL) was added dimethyl acetylenedicarboxylate (30 μL, 0.246 mmol) in dry dichloromethane (0.5 mL) under an argon atmosphere, and the mixture stirred overnight.…”

“…UV/Vis (λmax, nm, ε, cm -1 M -1 ): 230 (20,400), 272 (8,900), 403 (20,900). 1 H NMR (300 MHz, CDCl3): δ H 2.45 (3H, d, Ј 1.5 Hz, Me), 3.74, 3.82, 3.83 and 3.86 (each 3H, s, OMe), 5.43 (1H, t, Ј 1.5 Hz, H3), 6.12 (1H, d, Ј 1.9 Hz, H7), 6.31 (1H, d, Ј 1.9 Hz, H5), 7.59 (1H, d, Ј 1.9 Hz, H1). 13…”

“…The pyrrolo[3,2,1-ij]quinoline framework can be synthesised by cyclisation of tetrahydroquinoline derivatives to complete the indole ring, 1,2 or by cyclisation of 1-or 7-substituted indoles to complete the tetrahydroquinoline ring. [3][4][5][6][7][8][9][10][11] Our methodology in this work has involved the specific activation at C7, as a consequence of placing the electron-donating methoxy groups at C4 and C6.…”

Synthesis of a Variety of Activated Pyrrolo[3,2,1-ij]quinolines

“…The earliest and most general methods involved cyclisation of tetrahydroquinoline derivatives to complete the indole ring. Thus, 1-aminotetrahydroquinolines undergo reaction with suitable ketones in the Fischer indole synthesis, 2 and simple tetrahydroquinolines react with α-halo ketones in the Bischler indole synthesis. 3 An alternative general approach focuses on cyclisation reactions of 1-or 7-substituted indoles to complete the tetrahydroquinoline ring.…”