The Hive => Chemistry Discourse => Topic started by: psyx7 on January 07, 2004, 06:52:00 AM
Title: Applications of NBS?
Post by: psyx7 on January 07, 2004, 06:52:00 AM
I know that N-BS can bee used to brominate substituted benzenes, and apparently also amines. But there a couple of questions that I have been unable to find answers to despite using both TFSE and Google:
Can NBS be used to selectively brominate aldehydes and ketones, e.g. 2,5-DMP2P __> 4-Br-2,5-DMP2P or 2,5-DMB __> 4-Br-2,5-DMB?
I have a feeling that the answer is probably no since I have been unable to find any references to it, but thought I'd check with the experts first ;D
TIA, psyx
Title: NBS
Post by: hest on January 07, 2004, 10:12:00 AM
Bromination of the aromatic core with NBS in the dark works greath, use DCM or Acetonitrile as solvent, red this [ url ]
Title: I don't think it would work for 2,5-DMP2P...
Post by: Nicodem on January 07, 2004, 11:45:00 AM
I don't think it would work for 2,5-DMP2P -> 4-Br-2,5-DMP2P because of the ketone group. Even though NBS does not produce Br2 it does produce free radicals and slowly also some electrophilic Br+ (in dark) and these react readily with the alpha-hydrogens of ketones like 2,5-DMP2P (producing some just some useless 'tear-gas' compounds).