waitaminute

2+ Year Member
Sep 20, 2014
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In TBR's carbohydrates section #51, it says that the addition of H2SO4 to a sugar will dehydrate a sugar to carbon, while Br2 will oxidize only carbon 1 of a sugar to a carboxylic acid. Can anyone explain the mechanisms (and whether these reactions only occur specifically with H2SO4/Br2, or with a group of reactants) of these reactions to me? I read through EK Organic Chemistry but they made no mention of these reactions. Thanks!
 

Neuroplasticity

2+ Year Member
Jul 27, 2015
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If the Br2 reaction is with base and for a ketose, the haloform reaction could work:
 

adianadiadi

7+ Year Member
Jul 15, 2010
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sulfuric acid is strong dehydrating agent. It protonates the OH groups in sugar. You know the H2O+ group thus formed is a good leaving group and triggers elimination reactions.

However, the aldehyde group in sugars are oxidized with bromine water. bromine water generates nascent oxygen.
Br2 + H2O------> 2HBr +(O)
Thus acting as oxidizing agent.

For basic understanding of organic chemistry, you can visit: http://www.adichemistry.com/organic/organic-chemistry.html