反应详情

To a 2 liter three neck flask equipped with a stopper, dropping funnel, stir bar, and reflux condenser was added trimethyl-1,6-diisocyanatohexane (mixture of 2,2,4- and 2,4,4-isomers, 118.7 grams, 0.57 mol, obtained from Sigma-Aldrich, Milwaukee, Wis.), dibutyltin dilaurate (3.56 grams, 5.6 mmol, obtained from Sigma-Aldrich) and anhydrous tetrahydrofuran (1 liter). 1,4-Butanediol vinyl ether (133.2 grams, 1.2 mol, obtained from Sigma-Aldrich) was added slowly dropwise to the stirring solution via the addition funnel. The reaction mixture was brought to reflux and was kept at this temperature until deemed complete by infrared spectroscopy (about 5 hours, confirmed by the disappearance of the isocyanate peak at 2200 cm−1). When the reaction was complete, methanol (500 milliliters) was added to quench any residual isocyanate and the solution was stirred for 0.5 hour. The solvent was stripped in vacuo and the residual oil was triturated with hexane (3×500 milliliters), dissolved in methylene chloride (1 liter), washed with water (1×750 milliliters), dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo to afford 221 grams of a pale yellow oil (89 percent yield). The product was believed to be a mixture of compounds of the formulae

1. temperaturereflux condenser
2. temperatureto reflux
3. customabout 5 hours
4. customto quench any residual isocyanate
5. stirringthe solution was stirred for 0.5 hour
6. customthe residual oil was triturated with hexane (3×500 milliliters)
7. dissolutiondissolved in methylene chloride (1 liter)
8. washwashed with water (1×750 milliliters)
9. dry with materialdried over anhydrous magnesium sulfate
10. filtrationfiltered
11. concentrationconcentrated in vacuo