Dihydroxyacetone → 2-Propanone, 1,3-bis[(tetrahydro-2H-pyran-2-yl)oxy]-

Temperature

85 °C

A mixture of 236.3 g 3,4-dihydropyran and 90.1 g 1,3-dihydroxy-2-propanone, to which had been added 20 drops of concentrated hydrochloric acid, was heated to 85° C at which temperature, an exothermic reaction began. A cooling bath was applied to maintain the temperature in the range 85°-95° C during the next 15 minutes when heat was again applied to maintain the temperature at 85°-95° C for 2 hours. Excess dihydropyran was removed by warming under reduced pressure and the residue was dissolved in 600 ml of diethyl ether. The ether solution was washed (4 × 200 ml) with 5% aqueous sodium carbonate, then with water (3 × 300 ml) and dried over magnesium sulfate. The dried solution was distilled under reduced pressure to give 172.7 g of 1,3-bis(2-tetrahydropyranyloxy)-2-propanone, b.p. 90°-97°/2 × 10-4 mm.

1. customan exothermic reaction
2. customA cooling bath was applied
3. temperatureto maintain the temperature in the range 85°-95° C during the next 15 minutes when
4. temperatureheat
5. temperatureto maintain the temperature at 85°-95° C for 2 hours
6. customExcess dihydropyran was removed
7. temperatureby warming under reduced pressure
8. dissolutionthe residue was dissolved in 600 ml of diethyl ether
9. washThe ether solution was washed (4 × 200 ml) with 5% aqueous sodium carbonate
10. dry with materialwith water (3 × 300 ml) and dried over magnesium sulfate
11. distillationThe dried solution was distilled under reduced pressure

ORD record

ord-9780089556d1415faf5812c03d4f4035

Source dataset

uspto-grants-1978_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04077982