Cycloheptanone, (CH₂)₆CO, is a

cyclic ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen doubl ...

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 Jean-Baptiste Joseph Dieudonné Boussingault (2 February 1801 – 11 May 1887) was a French chemist who made significant contributions to agricultural science, petroleum science and metallurgy. Biography Jean-Baptiste Boussingault – an agric ...

first synthesized cycloheptanone from the calcium salt of dibasic

suberic acid Suberic acid, also octanedioic acid, is a dicarboxylic acid, with formula C8H14O4. It is a colorless crystalline solid used in drug syntheses and plastics manufacture. Its name is derived from the Latin word ''suber'' which means cork Cork or COR ...

. The

ketonization In organic chemistry, ketonic decarboxylation (also known as decarboxylative ketonization) is a type of organic reaction and a decarboxylation converting two equivalents of a carboxylic acid () to a symmetric ketone () by the application of heat w ...

of calcium suberate yields calcium carbonate and suberone: :Ca(O₂C(CH₂)₆CO₂) → CaCO₃ + (CH₂)₆CO 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 Sodium ethoxide, also referred to as sodium ethylate, is the ionic, organic compound with the formula , or NaOEt (Et = ethane). It is a white solid, although impure samples appear yellow or brown. It dissolves in polar solvents such as ethanol. ...

and

nitromethane Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a polar liquid commonly used as a solvent in a variety of industrial applications such as in ...

. The resulting sodium salt of 1-(nitromethyl)cyclohexanol is added to

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...

and shaken with hydrogen gas in the presence of W-4 Raney nickel catalyst.

Sodium nitrite Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite ...

and acetic acid are then added to give cycloheptanone. Cycloheptanone is also prepared by ring expansion of

cyclohexanone Cyclohexanone is the organic compound with the formula (CH2)5CO. The molecule consists of six-carbon cyclic molecule with a ketone functional group. This colorless oily liquid has an odor reminiscent of acetone. Over time, samples of cyclohexan ...

with

diazomethane Diazomethane is the chemical compound CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost u ...

as the methylene source.

Uses and reactions

Cycloheptanone is a precursor to

bencyclane Bencyclane is an antispasmodic, vasodilator, and platelet aggregation inhibitor. Synthesis Grignard addition of benzylmagnesiumbromide to suberone would give 1-benzylcycloheptanol 006-73-9(1'). Williamson ether synthesis with 3-dimethylamino ...

, a spasmolytic agent and vasodilator.

Pimelic acid Pimelic acid is the organic compound with the formula HO2C(CH2)5CO2H. Pimelic acid is one unit longer than a related dicarboxylic acid, adipic acid, a precursor to many polyesters and polyamides. However compared to adipic acid, pimelic acid is ...

is produced by the oxidative cleavage of cycloheptanone.

Dicarboxylic acid In organic chemistry, a dicarboxylic acid is an organic compound containing two carboxyl groups (). The general molecular formula for dicarboxylic acids can be written as , where R can be aliphatic or aromatic. In general, dicarboxylic acids show ...

s such as

pimelic acid Pimelic acid is the organic compound with the formula HO2C(CH2)5CO2H. Pimelic acid is one unit longer than a related dicarboxylic acid, adipic acid, a precursor to many polyesters and polyamides. However compared to adipic acid, pimelic acid is ...

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.

References

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