4,5-Bis(2,2-dimethyl-1,3-dioxolan-4-yl)-2,2-dimethyl-1,3-dioxolane synthesis

Yield:-

Reaction Conditions:

toluene-4-sulfonic acid at 70; for 5.33333 h;Product distribution / selectivity;oil bath;

Steps:

1

Examples 1-3Ketalization of sorbitol using 2.2-dimethoxypropane and para-toluene sulfonic acid To a 2L round bottom flask was added D-sorbitol (199.49g, 1.1 mol, obtained from Acros Organics of Geel, Belgium), 2,2-dimethoxypropane (DMP) (628.48g, 6.0 mol, obtained from the Sigma-Aldrich Company of St. Louis, MO), and para-toluene sulfonic acid (pTSA) (0.413g, approximately 500 ppm based on total weight of reactants, obtained from the Sigma-Aldrich Company of St. Louis, MO). The flask was placed on a rotary evaporator, and the oil bath set to 70⁰C. The flask immersed in the oil bath and rotated at this temperature for approximately 5 hours and 20 minutes and then removed from the oil bath and cooled to room temperature. A magnetic stir bar was added to the flask along with 150 mesh activated basic Al₂O₃ (about 75g, or about 10% wt. based on mass of reagents, obtained from the Sigma- Aldrich Company of St. Louis, MO ). The mixture was stirred for approximately 1 hour, and then the Al₂O₃ removed by vacuum filtration on a sintered glass funnel. The crude mixture was then placed on the rotary evaporator and immersed in the oil bath set to 8O⁰C and the DMP was stripped by applying a vacuum of approximately 20 Torr during heating and rotation. The reaction product was then distilled into a bump flask on the rotary evaporator by setting the temperature of the oil bath to 153°C, and employing pressure of about 4 - 6 Torr. The recovered product was observed to form a while, crystalline appearing product as it cooled.

References:

WO2009/146202,2009,A2 Location in patent:Page/Page column 84-85