Hydrochloric Acid → Methyl 4-({4-[(4-{[4-({4-[(4-tert-butoxycarbonylamino-1-methyl-1H-pyrrole-2-carbonyl)-amino]-1-methyl-1H-pyrrole-2-carbonyl}-amino)-1-methyl-1H-pyrrole-2-carbonyl]-amino}-1-methyl-1H-pyrrole-2-carbonyl)-amino]-1-methyl-1H-pyrrole-2-carbonyl}-amino)-1-methyl-1H-pyrrole-2-carboxylate

Participants

Reaction Steps

The Boc pyrrole trimer (5) (0.2 g, 0.40 mmol) in a dry round bottomed flask was treated with 4M HCl in dioxane (2.5 mL). The reaction mixture was stirred at room temperature for 30 minutes during which time a precipitate (5′) formed. The solvent was removed and the residue dried under vacuum. The residue was dissolved in dry DMF (2.5 mL) and the Boc pyrrole trimer acid (6) (0.194 g, 0.40 mmol, 1 equiv.) was added followed by EDCI (0.115 g, 0.6 mmol, 1.5 equiv.) and DMAP (0.058 g, 0.47 mmol, 1.2 equiv.). The reaction mixture was stirred for 48 hours then diluted with EtOAc (50 mL) and washed with 10% HCl solution (3×30 mL) and saturated NaHCO3 solution (3×30 mL). The organic layer was dried over MgSO4 then concentrated in vacuo to give an orange solid 0.185 g (54%). 1H NMR d6-DMSO δ 9.95 (2H, s, N—H), 9.93 (2H, s, N—H), 9.86 (1H, s, N—H), 9.08 (1H, s, Boc-N—H), 7.47 (1H, d, J=1.8 Hz, Py-H), 7.25 (1H, d, J=2.2 Hz, Py-H), 7.24 (2H, d, J=2.0 Hz, Py-H), 7.22 (1H, d, J=1.6 Hz, Py-H), 7.07 (2H, d, J=1.6 Hz, Py-H), 7.07 (1H, d, J=2.0 Hz, Py-H), 6.91 (2H, d, J=1.9 Hz, Py-H), 6.89 (1H, s, Py-H), 6.84 (1H, s, Py-H), 3.86 (3H, s, N—CH3), 3.86 (6H, s, N—CH3), 3.85 (3H, s, N—CH3), 3.84 (3H, s, N—CH3), 3.81 (3H, s, N—CH3), 3.74 (3H, s, O—CH3), 1.46 (9H, s, Boc-H).

Provenance & Evidence