Sodium Hydroxide → 2-(4-Bromophenyl)thiophen-3-amine

Participants

Reaction Conditions

Reaction Steps

Charge a 10 L double jacketed reactor equipped with mechanical stirring, set under inert atmosphere of argon with [2-(4-bromo-phenyl)-thiophen-3-yl]-carbamic acid tert-butyl ester (800 g, 2.25 mol) and EtOAc (3.2 L). Cool the yellow solution is down to 16.9° C. and add a solution of 5-6N HCl/IPA (1600 mL) in 10 minutes via a dropping funnel between 10° C. and 25° C. Heat the reaction mixture to 50° C. Stir the resulting suspension for 90 minutes at 50° C. Cool the suspension below 10° C. and add 2N NaOH solution (2773 mL) over 25 minutes, maintaining the temperature below 20° C. Add 2N NaOH (450 mL) to reach a pH of 12-13. Separate the two layers by decantation. Re-extract the aqueous phase with EtOAc (500 mL). Dry the combined organic layers over MgSO4 (200 g) and evaporate to dryness to yield 2-(4-Bromo-phenyl)-thiophen-3-ylamine (562.3 g, 2.21 mol) as a beige solid. 1H NMR (250 MHz, CDCl3): 3.70(s (broad), 2 H) 6.65(d,1 H, J=5.4 Hz), 7.06(d, 1 H, J=5.2 Hz), 7.32(d, 2 H, J=8.9 Hz), 7.45 (d, 2H, J=8.8 Hz).

Provenance & Evidence