N-bromobutanimide → 2-(5-bromothiophen-2-yl)ethanol

Temperature

-20 °C

2-(2-thienyl)ethanol (Aldrich, 5.0 g, 39 mmol) was diluted in toluene (50 mL) and cooled to −20° C. using an ice/NaCl bath. NBS (6.95 g, 39 mmol, 1 eq) was added portionwise over 15 minutes and the mixture was stirred at rt overnight. After quenching with 10% aq potassium hydroxide (20 mL), the layers were separated and the aqueous layer was extracted twice with dichloromethane (50 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated. Purification by Isco Combiflash, eluting with 0-80% ethyl acetate in hexanes (120 g column), afforded the desired as a slightly yellow oil (6.72 g, 83%).

1. customAfter quenching with 10% aq potassium hydroxide (20 mL)
2. customthe layers were separated
3. extractionthe aqueous layer was extracted twice with dichloromethane (50 mL)
4. dry with materialThe combined organic layers were dried over sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated
7. customPurification by Isco Combiflash
8. washeluting with 0-80% ethyl acetate in hexanes (120 g column)
9. customafforded the

ORD record

ord-5a3dcb3461cb4191b94ab2a114ff37bd

Source dataset

uspto-grants-2011_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08071584B2