A solution of the diol (6Z,9Z,29Z,32Z)-octatriaconta-6,9,29,32-tetraene-18,20-diol (7) (500 mg, 0.89 mmol) and 4,4-Diethoxy-N,N-dimethyl-1-butanamine (301mL, 1.34 mmol) in toluene (10 mL) was treated with PPTS (671 mg, 2.67 mmol) and heated (80° C.). After stirring (1 h) the solution was poured into NaOH (5M aq.) and extracted with CH2Cl2. The organic layer was washed with brine, dried (Na2SO4), filtered and concentrated. The crude material was subjected to chromatography (100% EtOAc) to yield 3-(4-((8Z,11Z)-heptadeca-8,11-dien-1-yl)-6-((9Z,12Z)-octadeca-9,12-dien-1-yl)-1,3-dioxan-2-yl)-N,N-dimethylpropan-1-amine (9) (399 mg, 68%) as a colorless oil. Rf 0.5 (10% CH3OH—CH2Cl2);
