4-Methylpyrrolo[1,2-a]quinoline (CAS NO.: ) could be produced through the following synthetic routes.

A. 1-(2-Iodophenyl)pyrrole (CAS NO.: ). A 50-mL, three-necked, round-bottomed, flame-dried flask equipped with a -coated stirbar, a glass stopper, an addition funnel and a reflux condenser is charged with 2-iodoaniline (12.5 g, 57.1 mmol) and glacial acetic acid (12.5 mL). The resulting solution is heated to reflux before 2,5-dimethoxytetrahydrofuran (7.8 mL, 59.0 mmol) is added over a period of 10 min via the dropping funnel and reflux is continued for 5 min once the addition is complete. The addition funnel and reflux condenser are replaced by an inlet for a thermocouple and a distillation head with condenser, respectively, and the acetic acid is slowly removed by distillation under reduced pressure (15 mmHg, bath temperature about 50 °C) over a period of approximately 4 h. During this time, the internal temperature slowly reaches 50 °C. The remaining brown residue is transferred to a 25-mL round-bottomed flask and is purified by short-path distillation in vacuum (0.04 mmHg). The fraction distilling at 90–102 °C is collected to give 1-(2-iodophenyl)pyrrole as a brown liquid (9.78–10.12 g, 64–66%).

B. 1-(2-(1-Propynyl)phenyl)pyrrole (CAS NO.: ). A flame-dried 250-mL, two-necked, round-bottomed flask equipped with a magnetic stirbar, a gas dispersion tube (5 mm OD), and a bubbler-sealed gas outlet is charged sequentially with 1-(2-iodophenyl)pyrrole (8.98 g, 33.4 mmol), piperidine (10 mL), (PPh₃)2PdCl₂ (1.20 g, 1.67 mmol), CuI (318 mg, 1.67 mmol) and toluene (90 mL) to give a homogeneous reddish solution. Propyne is bubbled through this solution for 90 min at 0.1 L/min via the dispersion tube until the reaction mixture turns black. For workup, the flask is vented, the reaction mixture is filtered through a short pad of silica (approximately 30 g) which is carefully rinsed with tert-butyl methyl ether (350 mL). The combined filtrates are transferred into a 1-L separatory funnel and are successively washed with water (2 × 200-mL portions) and brine (350 mL) before being dried over Na2SO4 and evaporated. The remaining orange liquid is transferred to a 25-mL round-bottomed flask and is purified by short-path distillation in vacuum to give 1-(2-(1-propynyl)phenyl)pyrrole as a pale yellow liquid (bp 70–75 °C, 0.005 mm Hg) (4.56–4.72 g, 75–78%).

C. 4-Methylpyrrolo[1,2-a]quinoline (CAS NO.: ). A 250-mL, three-necked, round-bottomed flask equipped with a reflux condenser fitted with an argon inlet, a glass stopper, a stopcock gas inlet and a Teflon-coated magnetic stirbar is evacuated and flame-dried before it is flushed with argon and allowed to cool to ambient temperature. The flask is charged with 1-(2-(1-propynyl)phenyl)pyrrole (4.53 g, 25 mmol), toluene (100 mL) and InCl₃ (277 mg, 1.25 mmol) and the resulting mixture is stirred at 80 °C bath temperature for 4 h until GC analysis shows complete conversion of the substrate. For workup, the dark mixture is filtered through a pad of silica gel (5 cm × 3 cm, approximately 30 g), which is then carefully rinsed with toluene (150 mL). The crude product was obtained as a yellow solid after removal of the solvent under reduced pressure. The product is dissolved in toluene (20 mL) and this solution is adsorbed on silica gel (approximately 10 g) and the resulting slurry is evaporated to dryness. The adsorbate is placed in a Soxhlet thimble (8.0 cm × 3.5 cm) and is extracted with pentane (80 mL) for 18 h using a Soxhlet apparatus of ca. 50 mL inner volume. Evaporation of the resulting pentane extract provides 4-methylpyrrolo[1,2-a]quinoline as a pale yellow solid, which is pure enough for most applications (mp 63–65°C, ≥95% by GC) (4.12 g, 91%). Analytically pure material is obtained by subsequent sublimation (60 °C bath temperature, 5 × 10-3 mmHg for 3.5 h) as a white solid (3.05 g, 67%), mp 67–68 °C.