Reaction #1929057

Reaction equation

4-hydroxybenzoic acid

BOP

→

4-hydroxybenzamide

Solvents

DMF

DMF

Conditions

Workup

1. 1
   Otherthe DMF was removed by evaporation under reduced pressure
2. 2
   workup.DISSOLUTIONdissolved by addition of aqueous sodium hydroxide solution 1M (pH 11)
3. 3
   Othersubjected to dialysis
4. 4
   Otheragainst water (1 L, 2 changes over 24 h)

Procedure

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).

Source