Curved Arrow Press Forum

An organic chemistry forum of Curved Arrow Press. (Oh, would you believe we accept donations.) Registration closed.

You are not logged in.

  • Index
  •  » OrgoForum
  •  » Conversion of cyclohexane-1,3-dione to glutaric acid

#1 2011-11-22 15:26:38


Conversion of cyclohexane-1,3-dione to glutaric acid

Yahoo!Answers in chemistry wrote:

When cyclohexan-1,3-dione is heated in the presence of Br2 (bromine) under basic conditions, the main organic products are 1,5-pentanedioc acid and CHBr3. Explain the result.

This is a combination question. The first reaction is a base catalyzed bromination. This reaction occurs three times. Its mechanism is illustrated for the first bromination step. It is repeated to give 2,2-dibromocyclohexane-1,3-dione.

At this point, the addition to a carbonyl group becomes evident. If hydroxide adds, it can reversibly eliminate hydroxide. However, as a alternate, it can eliminate the enolate of a dibromoketone (shown as its enolate). In the presence of bromine, a third bromination step can take place. A proton transfer step must also take place because the solution much contain excess hydroxide.

The product at this stage is a tribromomethyl ketone with a carboxylate ion. Addition and elimination of a tribromomethyl anion will give the disodium salt of pentanoic acid (glutaric acid). This step should be familiar to anyone familiar with the haloform reaction. [The tribromomethane will pick up a proton from water to give tribromomethane (bromoform).] Acidification will give the free glutaric acid.


  • Index
  •  » OrgoForum
  •  » Conversion of cyclohexane-1,3-dione to glutaric acid

Board footer

Powered by PunBB 1.2.16
© Copyright 2002–2005 Rickard Andersson

//google analytics added