Reaction Steps
The Boc pyrrole trimer (5) (0.6 g, 1.2 mmol) was dissolved in MeOH (5 mL) and treated with NaOH solution (0.1 g in 5 mL H2O). The reaction mixture was stirred overnight then heated at 60° C. for 2 hours. The MeOH was removed in vacuo and the aqueous fraction extracted with EtOAc (25 mL). The aqueous layer was adjusted to pH 2-3 with 1M HCl solution then extracted with EtOAc (3×30 mL). The combined organic layers were dried over MgSO4 then concentrated in vacuo to give an orange solid. The solid was suspended in Et2O (10 mL) and collected on a filter then dried in vacuo to give an orange solid 0.431 g (74%). 1H NMR d6-DMSO δ 12.11 (1H, s, OH), 9.89 (1H, s, N—H), 9.86 (1H, s, N—H), 9.09 (1H, s, Boc-N—H), 7.43 (1H, d, J=1.9 Hz, Py-H), 7.22 (1H, d, J=1.7 Hz, Py-H), 7.06 (1H, d, J=1.7 Hz, Py-H), 6.90 (1H, s, Py-H), 6.86 (1H, d, J=1.9 Hz, Py-H), 6.84 (1H, s, Py-H), 3.85 (3H, s, N—CH3), 3.83 (3H, s, N—CH3), 3.82 (3H, s, N—CH3), 1.46 (9H, s, Boc-H); 13C NMR d6-DMSO δ 161.9, 158.4, 158.4, 152.8, 122.8, 122.7, 122.5, 122.4, 122.3, 120.2 (CH), 119.5, 118.4 (CH), 117.0 (CH), 108.4 (CH), 104.7 (CH), 103.8 (CH), 78.2, 36.1 (CH3), 36.0 (CH3), 28.1 ([CH3]3).
