Pyridine → 5-Cyclopropylcarbonyl-2,2-dimethyl-1,3-dioxan-4,6-dione

Temperature

0 °C

A mixture of 2,2-dimethyl-1,3-dioxan-4,6-dione (20.0 g) and pyridine (22,0 g) in dichloromethane (200 ml) was stirred and cooled to 0° C. in an ice bath. A solution of cyclopropylcarbonyl chloride (16.0 g) in dichloromethane (50 ml) was added dropwise with stirring in an atmosphere of nitrogen whilst maintaining the temperature below 3° C. by external cooling. The mixture was stirred at 0° C. for 1 hour and at ambient temperature for 2 hours. The resultant orange suspension was washed with hydrochloric acid (2M, 2×50 ml), water (2×50 ml), dried (anhydrous sodium sulphate) and filtered. The filtrate was evaporated to dryness. The residue was dissolved in ether (150 ml) and the solution was treated with decolourizing charcoal and filtered. The filtrate was evaporated to dryness to give 5-cyclopropylcarbonyl-2,2-dimethyl-1,3-dioxan-4,6-dione (24.2 g) as a yellow solid mp 44°-46° C.

1. stirringwith stirring in an atmosphere of nitrogen
2. temperaturewhilst maintaining the temperature below 3° C. by external cooling
3. stirringThe mixture was stirred at 0° C. for 1 hour and at ambient temperature for 2 hours
4. washThe resultant orange suspension was washed with hydrochloric acid (2M, 2×50 ml), water (2×50 ml)
5. dry with materialdried (anhydrous sodium sulphate)
6. filtrationfiltered
7. customThe filtrate was evaporated to dryness
8. dissolutionThe residue was dissolved in ether (150 ml)
9. additionthe solution was treated with decolourizing charcoal
10. filtrationfiltered
11. customThe filtrate was evaporated to dryness

ORD record

ord-13bfda98dfdb483fbc9a8d57881c1189

Source dataset

uspto-grants-1998_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05747424