3,4-dihydro-2H-pyran → 2-(2-Bromoethoxy)tetrahydro-2H-pyran

To a mechanically stirred solution of dihydropyran (1000 mL) and a strong acid resin (10.0 g) in hexane (2000 mL) was added 2-bromoethanol (985 g) dropwise over a period of 1.5 hours in a cold water bath to maintain an internal temperature of 35°-40° C. After being stirred overnight at room temperature, the reaction mixture was chromatographed, with hexane as the eluent. The hexane was evaporated to give an amber liquid which was distilled through a 2 inch (5 cm) diameter vigreux cole, collecting the material boiling between 75°-95° C. (3,300-4,700 Pa). This material was redistilled to give the ether as an oil (1195.5 g); bp 80°-90° C. (2666 Pa); NMR: 4.68 (m, 1), 4.01 (m, 1), 3.89 (m, 1), 3.77 (m, 1), 3.52 (m, 3), 1.75-1.50 (m, 6).

1. temperatureto maintain an internal temperature of 35°-40° C
2. customthe reaction mixture was chromatographed, with hexane as the eluent
3. customThe hexane was evaporated
4. customto give an amber liquid which
5. distillationwas distilled through a 2 inch (5 cm) diameter vigreux cole
6. customcollecting the material
7. customboiling between 75°-95° C.
8. distillationThis material was redistilled
9. customto give the ether as an oil (1195.5 g)

ORD record

ord-9dec31d0b08c48afae3b3d1ef5d24bb4

Source dataset

uspto-grants-1997_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05654299