4-Hydroxybenzaldehyde → m-PEG4-benzaldehyde

Participants

Reaction Steps

Chloride 603 (26 g, 0.14 mol, 1.3 equiv) and p-hydroxybenzaldehyde (13 g, 0.11 mol, 1 equiv) were dissolved in dry THF (40 mL). K2CO3 (15 g, 0.11 mol, 1 equiv) was added followed by 18-crown-6 (3.0 g, 11 mmol, 0.11 equiv) and KI (0.20 g, 1.2 mmol, 0.01 equiv). The reaction mixture was stirred at reflux for 48 h. The resulting mixture was cooled to room temperature, and water (200 mL) was added. The product was extracted with 3×350 mL portions of ethyl acetate and the combined organic layers were dried and concentrated. The oil was loaded onto a silica gel column and eluted with a 1:9 mixture of ethyl acetate/hexane, followed by a ratio of 1:4, 3:7, 4:1 of ethyl acetate/hexane and finally washed with ethyl acetate to afford 21 g (70%) of 604 as a clear oil. IR(cm−1): 1697 (s), 1165 (s). 1H NMR (400, CDCl3): δ 3.36 (s, 3), 3.54 (t, 2, J=4.6), 3.63-3.68 (m, 4), 3.72-3.75 (m, 2), 3.88 (t, 2, J=4.8), 4.20 (t, 2, J=4.8), 7.01 (d, 2, J=8.8), 7.82 (d, 2, J=8.8), 9.87 (s, 1). 13C NMR (CDCl3): δ 58.86, 67.59, 69.29, 70.40, 70.47, 70.71, 71.73, 114.71, 129.84, 131.76, 163.69, 190.63. Calcd: [M+H]+ (C14H21O5) m/z=269.13889. Found FAB-HRMS: [M+H]+ m/z=269.134487. Anal. Calcd. for C14H20O5: C, 62.67; H, 7.51. Found: C, 62.47; H, 7.74.

Provenance & Evidence