Allyl bromide → 1-Allyl-2-(4-(tert-butoxycarbonyl)pyridin-3-yl)-3-cyclohexyl-1h-indole-6-carboxylic acid

Participants

Reaction Steps

To a suspension of NaH (19.5 mg of 60% dispersion in mineral oil, 0.488 mmol) in DMF (2 mL), methyl 2-(4-(tert-butoxycarbonyl)pyridin-3-yl)-3-cyclohexyl-1H-indole-6-carboxylate (100 mg, 0.222 mmol) was added and the reaction mixture was stirred at rt for 10 min. Allyl bromide (0.040 mL, 0.466 mmol) was then added, and the reaction mixture was stirred at rt for 3 hr. It was then quenched by the addition of water and acidified using 1N HCl solution. A yellowish precipitate formed which was collected by filtration to give the crude ester product in sufficient purity to proceed to the next step. This material was then dissolved in a THF/Methanol mixture (3 mL/3 mL) and 2N NaOH solution (2 mL) was added. The reaction mixture was heated at 100° C. under microwave conditions for 15 min. It was then concentrated and the pH was adjusted to 4–5 using 1N HCl solution. This mixture was then extracted using ethyl acetate and the organic layer was dried with MgSO4, filtered and evaporated and the resultant residue was purified using Prep. reverse phase HPLC to afford the title compound as a yellow solid, (50 mg, 44% yield two steps). MS m/z 516(MH+); 1H NMR (500 MHz, CD3OD) □ ppm 1.22–1.48 (m, 13 H) 1.70–2.02 (m, 5 H) 2.15 (m, 1 H) 2.37 (m, 1 H) 3.88 (dd, J=16.63, 5.04 Hz, 1 H) 4.13 (m, 1 H) 4.51 (m, 1 H) 4.76 (m, 1 H) 4.87 (m, 1 H) 5.04–5.21 (m, 3 H) 5.79 (m, 1 H) 5.97 (m, 1 H) 7.58 (d, J=5.80 Hz, 1 H) 7.78 (m, 1 H) 7.90 (d, J=8.24 Hz, 1 H) 8.13 (s, 1 H) 8.50 (s, 1 H) 8.67 (d, J=5.80 Hz, 1 H).

Provenance & Evidence