Maleic Anhydride → Levopimaric acid

Participants

Reaction Conditions

Reaction Steps

Example 1 describes the preparation of quaternary ammonium-containing rosin acids and rosin esters, according to the exemplary method shown in FIG. 1. The synthesis for the integration of quaternary ammonium group into the moiety of rosin is described as follows: The abietic acid, maleic anhydride and acetic acid were mixed in a round bottom flask under a nitrogen atmosphere and heated at 120° C. for 12 h to yield levopimaric acid. The levopimaric acid is stirred with dimethylethylenediamine at 85° C. for 8 h, yielding a rosin-derived tertiary ammonium derivative, which is then stirred with an alkyl halide (e.g. bromoethane, bromohexane, bromooctane and bromododecane) at 40° C. in tetrahydrofuran for 48 h to yield quaternary ammonium-containing rosin acid 1. The quaternary ammonium-containing rosin acid is dissolved in thionyl chloride and refluxed for 12 h. Then, thionyl chloride is removed by reduced pressure distillation. Ethanol, triethylamine and tetrahydrofuran are added and stirred at room temperature for 24 h to yield the ethyl ester of quaternary ammonium-containing rosin acid 2.

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