反应详情

A solution of 19.0 g of the product of Example 2 and 0.1 g of 1,4-diazabicyclo[2.2.2.]octane (DABCO) in 90 ml of dry xylenes was heated to reflux temperature (139° ). To this solution was added 3.6 ml of liquid phosgene over a period of about 2 hours, keeping the temperature between 125° and 136° by adjusting the rate of phosgene addition. The reaction mixture was cooled to 25°, and filtered under nitrogen to remove DABCO hydrochloride. The filtrate was concentrated in vacuo to give the title compound as a viscous, moisture-sensitive oil. This material was carried on to the desired products without further purification.

1. temperatureto reflux temperature (139° )
2. customthe temperature between 125° and 136°
3. temperatureThe reaction mixture was cooled to 25°
4. filtrationfiltered under nitrogen
5. customto remove DABCO hydrochloride
6. concentrationThe filtrate was concentrated in vacuo