Synthesis of Dehydroabietic Acid (2-Acryloyloxy) Ethyl Ester in Ionic Liquids

Abstract

A simple ionic liquid methodology for the synthesis of a novel derivative of dehydroabietic acid is described. 1-Butyl-3-methylimidazolium tetrafluoroborate [bmim]BF₄, a typical ionic liquid, was used as an efficient and environmentally benign solvent in the synthesis of dehydroabietic acid (2-acryloloxy) ethyl ester by O-acylation reaction of dehydroabietic acid chloride with 2-hydroxyethyl acrylate. This new method showed the advantages of mild reaction conditions, short reaction times, good yields, and recyclable solvent.

Keywords:

• Dehydroabietic acid
• dehydroabietic acid (2-acryloloxy) ethyl ester
• ionic liquid
• O-acylation

ACKNOWLEDGMENT

This research was supported by the Science Foundation of Guangxi Province of China (Grant No. 0832091) and the Science Foundation of Guangxi University of China (Grant No. X071076).

Notes

^a Reaction temperature 50°C, reaction time 2 h, molar ratio of dehydroabietic acid chloride to 2-hydroxyethyl acrylate to pyridine 1:3:1.

^b [bmim]Br: 47.1 mmol.

^c [bmim]PF₆: 47.1 mmol.

^d [bmim]BF₄: 47.1 mmol.

^e Tetrahydrofuran: 10 mL.

^f Benzene: 10 mL.

^g Methylbenzene: 10 mL.

^a The reaction conditions were the same as in Table 1.

^a Molar ratio of dehydroabietic acid chloride to [bmim]BF₄ to pyridine 1:3:1.

^b Molar ratio of reactants dehydroabietic acid chloride–2-hydroxyethyl acrylate.