Benzyl Bromide → HCID 89610365, compound

Participants

Reaction Conditions

Reaction Steps

Benzyl bromide (2.13 ml, 17.9 mmol) was added dropwise to a suspension of DIPEA (3.12 mL, 17.9 mmol) and diethyl 3,4-dihydroxy-1-(4-methoxyphenyl)-1H-pyrrole-2,5-dicarboxylate (UL2-001) (5 g, 14.3 mmol) in EtOH (200 mL). The reaction mixture was stirred at 50° C. for 18 h. Additional benzyl bromide (0.85 mL, 7.20 mmol) and DIPEA (1.25 mL, 7.20 mmol) were added and the reaction stirred at 60° C. for 24 h, after which further portions of benzyl bromide (0.85 ml, 7.20 mmol) and DIPEA (1.25 mL, 7.20 mmol) were added and the reaction mixture stirred at 60° C. for 24 h. The reaction mixture was allowed to cool to RT, and partitioned between EtOAc (200 mL) and sat. NaHCO3 (aq.) (200 mL), the organic layer was separated and washed with sat. NaHCO3 (aq.) (2×200 mL) dried (MgSO4), filtered and solvents removed in vacuo to give an orange oil. The residue was purified by silica gel chromatography (80 g, 0-100% EtOAc in isohexane) to afford a yellow solid. The product was recrystallised from EtOH (100 mL) to afford diethyl 3-(benzyloxy)-4-hydroxy-1-(4-methoxyphenyl)-1H-pyrrole-2,5-dicarboxylate (23) (2.89 g, 37%) as a pale yellow solid: m/z 440 (M+H)+ (ES+). 1H NMR (400 MHz, DMSO-d6) δ: 8.82 (s, 1H), 7.52-7.30 (m, 5H), 7.16-7.03 (m, 2H), 6.94-6.83 (m, 2H), 5.09 (s, 2H), 4.10-3.91 (m, 4H), 3.79 (s, 3H), 1.02-0.92 (m, 6H).

Provenance & Evidence