Diethyl Ether → HCID 57276089, compound

Temperature

-70 °C

1,3-bis-trimethylsilyloxy propandiol (38.5 grams, 175 mmol, prepared from 1,3-propanediol, triethylamine, and chlorotrimethyl silane in tetrahydrofuran) was slowly added to a stirring solution of trimethylsilyl trifluoromethanesulfonate (0.5 mL, 2.6 mmol) in methylene chloride (100 mL, -70° C.), while keeping the reaction temperature between -70° and -60° C. The solution was allowed to stir for 10 minutes at -70° C. A solution of 6-bromo-2-tetralone (35.5 grams, 158 mmol) in methylene chloride (100 mL) was slowly added over a 10 minute period. The resulting reaction mixture was allowed to warm slowly to 15° C. over 15 hours, after which time thin layer chromatography (55:45 diethyl ether:hexanes) and high pressure liquid chromatography showed complete consumption of the starting tetralone. The reaction was quenched with saturated sodium bicarbonate (200 mL) and the layers were separated. The aqueous layer was extracted with methylene chloride (50 mL). The combined methylene chloride solution was washed with brine (200 mL), dried with sodium sulfate, and concentrated at reduced pressure to a gold colored residue. This was filtered through 300 grams of silica gel and eluted with 3:1 hexanes/ethyl acetate. The filtrate was concentrated at reduced pressure and the product recrystallized from hexanes to obtain 33.5 grams (75% yield) of 6-bromo-2-tetralone propylene ketal as white crystals (NMR, MS). Calculated for C13H15O2Br: C, 55.14; H, 5.34. Found C, 55.05; H, 5.52.

1. customthe reaction temperature between -70° and -60° C
2. customThe resulting reaction mixture
3. temperatureto warm slowly to 15° C. over 15 hours
4. customconsumption of the starting tetralone
5. customThe reaction was quenched with saturated sodium bicarbonate (200 mL)
6. customthe layers were separated
7. extractionThe aqueous layer was extracted with methylene chloride (50 mL)
8. washThe combined methylene chloride solution was washed with brine (200 mL)
9. dry with materialdried with sodium sulfate
10. concentrationconcentrated at reduced pressure to a gold colored residue
11. filtrationThis was filtered through 300 grams of silica gel
12. washeluted with 3:1 hexanes/ethyl acetate
13. concentrationThe filtrate was concentrated at reduced pressure
14. customthe product recrystallized from hexanes

ORD record

ord-dbd667ea055c4f7eac818922c9a4edf1

Source dataset

uspto-grants-2000_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06111110