Cycloheptanone


Cycloheptanone, 6CO, is a cyclic ketone also referred to as suberone. It is a colourless volatile liquid. Cycloheptanone is used as a precursor for the synthesis of pharmaceuticals.

Synthesis

In 1836, French chemist Jean-Baptiste Boussingault first synthesized cycloheptanone from the calcium salt of dibasic suberic acid. The destructive distillation of calcium suberate yields calcium carbonate and suberone:
Cycloheptanone is still produced by the cyclization and decarboxylation of suberic acid or suberic acid esters. This reaction is typically conducted in the gas phase at 400–450 °C over alumina doped with zinc oxide or cerium oxide.
Cycloheptanone is also produced by the reaction of cyclohexanone with sodium ethoxide and nitromethane. The resulting sodium salt of 1-cyclohexanol is added to acetic acid and shaken with hydrogen gas in the presence of W-4 Raney nickel catalyst. Sodium nitrite and acetic acid are then added to give cycloheptanone.
Cycloheptanone is also prepared by ring expansion of cyclohexanone with diazomethane as the methylene source.

Uses and reactions

Cycloheptanone has no direct applications, but is a precursor to other compounds. Bencyclane, a spasmolytic agent and vasodilator is produced from it, for example. Pimelic acid is produced by the oxidative cleavage of cycloheptanone. Dicarboxylic acids such as pimelic acid are useful for the preparation of fragrances and certain polymers.
Several microorganisms, including Mucor plumbeus, Mucor racemosus, and Penicillium chrysogenum, have been found to reduce cycloheptanone to cycloheptanol. These microorganisms have been investigated for use in certain stereospecific enzymatic reactions.