Acetic Acid → Cholesterol

Participants

Reaction Conditions

Reaction Steps

The bromobutylated Tecothane (1.14 g, containing approximately 0.5 mmol of 4-bromobutyl groups) described above was dissolved in DMAc (20 ml) under argon and cooled to −2° C. A solution of 3-mercapto-2-hydroxypropyl-cholesterol (0.495 g, 1.04 mmol) in DMAc (8 ml) was added and a freshly prepared 0.12 M DMAc-solution of (Bu4N)2B4O7 (5 ml, 6 mmol) was also added. The mixture was stirred at −1 to 1° C. for one hour and acidified with acetic acid (0.12 ml, 2 mmol). The reaction solution was then filtered and the polymer was precipitated with methanol (150 ml). The precipitate was washed with methanol alternating with 2-propanol and stirred consequently with large amounts of 2-propanol, methanol, and water and dried under 0.05 mm Hg conditions. The procedure yielded 1.31 g of cholesterol-modified Tecothane. 1H NMR analysis of this polymer (DMF-d7) indicated covalent attachment of cholesterol to 20% of the urethane segments via noncleavable sulfide bonds (see FIG. 2) corresponding to approximately 0.4 mmol of pendant cholesterol moieties per gram of polymer.

Provenance & Evidence