Team:TU Darmstadt/Protocols/Synthesis of paranitrophenylesters with acyl chlorides in presence of triethylamine

Synthesis of paranitrophnylesters with acyl chlorides in presence of triethylamine

Preparation

Diparanitrophenyl succinate

In a 250 mL triple-neck round-bottom flask with reflux 6.79 g (48.82 mmol/ 2.01 eq.) paranitrophenole and 5.16 g (51.01 mmol/ 2.10 eq.) triethylamine are dissolved in 100 mL acetone under inert conditions and kept at 0 °C using a water/ice mixture. A solution of 1.70 g (10.07 mmol/ 1.00 eq.) succinyl chloride in 50 mL acetone is added dropwise with stirring 2 h at 0 °C. The resulting ester is precipitated in 400 mL distilled water, recrystallized from ethyl acetate three times and dried at 60 °C in a cabinet dryer over night. The yield is 2.3381 g (26.73 % of the theory).

Paranitrophenyl dihydrocinnamate

In a 100 mL triple-neck round-bottom flask with reflux 1.41 g (10.17 mmol/ 1.01 eq.) paranitrophenole and 1.07 g (10.57 mmol/ 1.05 eq.) triethylamine are dissolved in 50 mL acetone under inert conditions and kept at 0 °C using a water/ice mixture. A solution of 3.76 g (24.29 mmol/ 1.00 eq.) dihydrocinnamoyl chloride in 20 mL acetone is added dropwise with stirring 2 h at 0 °C. The resulting ester is precipitated in 200 mL distilled water, filtrated washed with ice cold acetone, stirred in distilled water for 2 h and dried at 60 °C in a cabinet dryer over night. The yield is 1.0623 g (34.69 % of the theory).

Analysis (¹NMR-spectroscopy)

Diparanitrophenyl succinate

(300 MHz, CDCl₃): δ = 2.99 (2 H), 7.19-7.25 (2 H), 8.18-8.24 (2 H)

Paranitrophenyl dihydrocinnamate

(300 MHz, CDCl₃): δ = 2.94-2.97 (2 H), 3.07-3.10 (2 H), 7.18-7.21 (2 H), 7.26-7.35 (5 H), 8.24-8.28 (2 H)

Sources

[http://patentscope.wipo.int/search/en/detail.jsf?docId=WO2009073541&recNum=1&maxRec=&office=&prevFilter=&sortOption=&queryString=&tab=PCT+Biblio: Thermoresponsive arginine-based hydrogels as biologic carriers 11.06.2009]