4-Hydroxybenzoic Acid → 4-Hydroxybenzamide

Participants

Reaction Steps

A solution of freshly prepared 4-hydroxybenzoic acid (635 mg; 4.6 mmol) and BOP (1.7 g; 5.06 mmol) in DMF (20 mL) was added dropwise and at room temperature to a solution of PEI (1 g, 23.2 mmol) in DMF (50 mL). After 2 hours under stirring, the DMF was removed by evaporation under reduced pressure. The crude product was taken in water, dissolved by addition of aqueous sodium hydroxide solution 1M (pH 11) and subjected to dialysis using a SpectraPor 12-14 kDa membrane against water (1 L, 2 changes over 24 h). Lyophilization provided 4-hydroxybenzamide-PEI (0.7 g) at a modification degree of 28%. 1H NMR (D2O) δppm: 2.6 (bm, 2.9H, —NHCH2CH2NH—), 3.22 (m, 0.55H, Phe-CONHCH2CH2NH—), 3.35 (m, 0.55H, Phe-CONHCH2CH2NH) 6.57 (d, J=7.3 Hz, 0.55 H, CHaro), 6.97 (m, 0.55H, CHaro).

Provenance & Evidence