Reaction #1929056

Reaction equation

4-hydroxybenzoic acid

BOP

→

4-hydroxybenzamide

Solvents

DMF

DMF

Conditions

Workup

1. 1
   Otherthe DMF was removed by evaporation under vacuum
2. 2
   workup.DISSOLUTIONdissolved by addition of aqueous sodium hydroxide solution 1M (pH 10)
3. 3
   Othersubjected to dialysis
4. 4
   Otheragainst water hydrochloric acid 50 mM (1 L volume; 2 changes over 24 h) and water (1 L)

Procedure

A solution of freshly prepared 4-hydroxybenzoic acid (476 mg; 3.45 mmol) and BOP (1.7 g; 3.8 mmol) in DMF (20 mL) was added dropwise and at room temperature to a solution of PEI (1 g, 23.2 mmol) in DMF (30 mL). After 2 hours under stirring, the DMF was removed by evaporation under vacuum. The residue was taken in water (25 mL), dissolved by addition of aqueous sodium hydroxide solution 1M (pH 10) and subjected to dialysis using a SpectraPor 12-14 kDa membrane against water hydrochloric acid 50 mM (1 L volume; 2 changes over 24 h) and water (1 L). Lyophilization provided 4-hydroxybenzamide-PEI (1 g) at a modification degree of 13%. 1HNMR (D2O) δppm: 3.8-2.45 (m, 4H, NHCH2CH2NH), 6.9 (m, 0.25H, CHaro), 7.18 (m, 0.25H, CHaro).

Source