2-tert-butyl-7-fluoro-5-nitro-1H-indole synthesis

Yield:952664-94-7 81%

Reaction Conditions:

with potassium tert-butylate in N,N-dimethyl-formamide at 20 - 120;

Steps:

38

To a solution of N-[2-(3,3-dimethyl-but-1-ynyl)-6-fluoro-4-nitro-phenyl]-butyramide (3.2 g, 10 mmol) in DMF (20 mL) was added t-BuOK (2.3 g, 21 mmol) at room temperature. The mixture was heated at 120° C. for 2 g before being cooled down to room temperature. Water (50 mL) was added to the reaction mixture and the resulting mixture was extracted with CH₂Cl₂ (30 mL×3). The combined organic extracts were dried over anhydrous Na₂SO₄ and evaporated under vacuum to give 2-tert-butyl-7-fluoro-5-nitro-1H-indole (2.0 g, 81%), which was used in the next step without further purification. ¹H NMR (300 MHz, CDCl₃) δ9.95 (brs, 1H), 8.30 (d, J=2.1 Hz, 1H), 7.74 (dd, J=1.8, 11.1 Hz, 1H), 6.43 (dd, J=2.4, 3.3 Hz, 1H), 1.43 (s, 9H).

References:

US2007/244159,2007,A1 Location in patent:Page/Page column 124