Methyl iodide → 3-Carboxy-4-ethyl-9-isopropyl-9H-pyrido[3,4-b]indole

Participants

Reaction Conditions

Reaction Steps

n-Butyllithium (2.5 M in hexanes, 3.2 ml, 8 mmol) and 3-carboxy-9-isopropyl-9H-pyrido[3,4-b]indole (Method 2; 504 mg, 2 mmol) were added to a solution of 2,2,6,6-tetramethyl piperidine (1.01 ml, 6 mmol) in THF (15 ml) at −50° C. The mixture was allowed to stir for 30 minutes warming to 0° C. Methyl iodide (0.15 ml, 2.4 mmol) was then added in a single portion and the mixture was left at 0° C. for a further 30 minutes and at room temperature for a further 16 hours. The mixture was concentrated in vacuo and the residue was dissolved in DCM. The solution was washed with 1 M HCl and then with water. The organic phase was separated, dried and concentrated in vacuo. The crude product was purified by preparative HPLC eluting over a gradient of 20-90% MeCN in water (0.1% TFA). The product was obtained as a yellow solid (190 mg) after evaporation of the appropriate fractions. NMR (300 MHz) 9.16 (s, 1H), 8.39 (d, 1H), 8.01 (d, 1H), 7.72 (t, 1H), 7.43 (t, 1H), 5.39 (m, 1H), 3.60 (q, 2H), 1.67 (d, 6H), 1.38 (t, 3H).

Provenance & Evidence