反应详情

To a 100 ml. 3-necked flask equipped with magnetic stirring was added 20 g. (0.1 mole) of 2-bromo-2-nitropropane-1,3-diol and 30 ml. (0.5 mole) of acetone. After solution was complete, the temperature was 15° C. Then 13 ml. (0.1 mole) of boron trifluoride etherate was added to the reaction mixture from a dropping funnel over a period of about 2 minutes. The temperature rose to 47° C. and then dropped to 35° C. over a period of 10 minutes. The reaction mixture was then poured into 150 ml. of a saturated sodium bicarbonate solution and stirred for 15 minutes. The solids were filtered and washed with 200 ml. acetone, dried and an IR showed a reaction had occurred. About 18 g. of crude material was dissolved in 150 ml. of hot hexane and filtered. On cooling and standing overnight 9.0 g. (40% yield) of 5-bromo-2,2-dimethyl-5-nitro- 1,3-dioxane was obtained as pure white needles. An NMR and IR confirmed the structure. An elemental analysis disclosed the following percentage composition:

1. custom3-necked flask equipped
2. additionwas added 20 g
3. customwas 15° C
4. customrose to 47° C.
5. additiondropped to 35° C. over a period of 10 minutes
6. additionThe reaction mixture was then poured into 150 ml
7. filtrationThe solids were filtered
8. washwashed with 200 ml
9. dry with materialacetone, dried
10. dissolutionof crude material was dissolved in 150 ml
11. filtrationof hot hexane and filtered
12. temperatureOn cooling