Retinol, acetate → Unii-61911N8D6W

Beteiligte Stoffe

Reaktionsschritte

Retinyl acetate (22.0 g; 80% in oil; 53.6 mmol) and linoleic acid (Pamolyn 200; 15.0 g; 53.6 mmol; 1.0 equiv) were dissolved in 160 mL of toluene in a 500 mL flask. A dip tube in the flask was connected through a peristaltic pump to a column containing 6.0 g of Novozyme 435 which was connected in sequence to a second column containing 6.0 g of dried Amberlyst A-21. A tube from this second column returned to the original flask. The pump was started (flow rate 6 mL/min) sending the reaction mixture through the two columns and then back to the pot. After 6 h conversion had reached 71%, and the pump was stopped and the Amberlyst resin was regenerated by removing the column and washing the contents with 100 mL of 10% triethylamine in toluene (with 100 mL of toluene chaser). The apparatus was reassembled and the pump re-started. After 3 more hours conversion had reached 75% and the pump was stopped. Approximately 50% of the contents of the pot (80 mL) was removed and a mixture of 11.0 g of 80% retinyl acetate and 7.5 g of linoleic acid in 80 mL of toluene was added to the pot to serve as a first reactant replenishment. The Amberlyst resin was regenerated as above, the apparatus reassembled, and the pump started. After 9 h 73.6% conversion had been achieved and the pump was stopped. Approximately 50% of the contents of the pot (80 mL) was removed and a mixture of 11.0 g of 80% retinyl acetate and 7.5 g of linoleic acid in 80 mL of toluene was added to the pot to serve as a second replenishment. The Amberlyst resin was regenerated as above, the apparatus reassembled, and the pump started. After 12 h 75.0% conversion had been achieved and the reaction was stopped.

Herkunft & Nachweise