N-bromobutanimide → HCID 86112953, compound

Temperature

0 °C

Following a general procedure,50 a stirred solution of 3-methyl-pyrrole-2-carboxaldehyde (2, 5.63 g, 51.6 mmol) in THF (52 mL) was cooled to 0° C. NBS (9.19 g, 51.6 mmol; reagent grade, unrecrystallized) was added all at once. The reaction mixture was stirred for 15 min at 0° C. under argon before the solvent was removed on a rotary evaporator. The resulting solid was dried under high vacuum for 2 h. Water (100 mL, room temperature) was added to the flask and the suspension was filtered (Büchner funnel). The filter cake was washed with an additional 100 mL of water. The solid filtered material was recrystallized from water/ethanol as follows. The solid filtered material was transferred to a 250 mL round bottom flask equipped with a reflux condenser. Water/ethanol (150 mL, 5:1) were added and the mixture was refluxed in a hot water bath until all solid material had dissolved. Upon allowing the solution to cool to room temperature the product crystallized. The mixture was cooled to 4° C. for 2 h to promote more crystallization. The mixture was vacuum-filtered and the resulting off-white crystals were dried under high vacuum for 24 h (7.78 g, 80%): mp 140-143° C.; 1H NMR δ 2.32 (s, 3H), 7.08 (d, J=3.3 Hz, 1H), 9.60 (s, 1H), 9.95 (brs, 1H); 13C NMR δ 9.8, 101.7, 126.0, 129.3, 131.7, 177.9; ESI-MS obsd 187.9708, calcd 187.9706 [(M+H)+, M=C6H6BrNO].

1. customwas removed on a rotary evaporator
2. customThe resulting solid was dried under high vacuum for 2 h
3. additionWater (100 mL, room temperature) was added to the flask
4. filtrationthe suspension was filtered (Büchner funnel)
5. washThe filter cake was washed with an additional 100 mL of water
6. filtrationThe solid filtered material
7. customwas recrystallized from water/ethanol
8. filtrationThe solid filtered material
9. customwas transferred to a 250 mL round bottom flask
10. customequipped with a reflux condenser
11. additionWater/ethanol (150 mL, 5:1) were added
12. temperaturethe mixture was refluxed in a hot water bath until all solid material
13. dissolutionhad dissolved
14. temperatureto cool to room temperature the product
15. customcrystallized
16. temperatureThe mixture was cooled to 4° C. for 2 h
17. customcrystallization
18. filtrationThe mixture was vacuum-filtered
19. customthe resulting off-white crystals were dried under high vacuum for 24 h (7.78 g, 80%)

ORD record

ord-15fd2a094e8c4cd2846d9a678989e100

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09303165B2