Acetonide Explained

In organic chemistry, an acetonide is the functional group composed of the cyclic ketal of a diol with acetone. The more systematic name for this structure is an isopropylidene ketal. Acetonide is a common protecting group for 1,2- and 1,3-diols.^[1] The protecting group can be removed by hydrolysis of the ketal using dilute aqueous acid.

Example

The acetonides of small di- and triols, as well as many sugars and sugar alcohols, are common.^[2] The hexaol mannitol reacts with 2,2-dimethoxypropane to give the bis-acetonide, which oxidizes to give the acetonide of glyceraldehyde:^{[3] [4]}

(CHOHCHOHCH₂OH)₂ + 2 (MeO)₂CMe₂ → (CHOHCHCH₂O₂CMe₂)₂ + 4 MeOH

(CHOHCHOCH₂OCMe₂)₂ + [O] → 2 OCHCHCH₂O₂CMe₂ + H₂O

An example of its use as a protecting group in a complex organic synthesis is the Nicolaou Taxol total synthesis. It is a common protecting group for sugars and sugar alcohols, a simple example being solketal.

The acetonides of corticosteroid are used in dermatology, because their increased lipophilicity leads to better penetration into the skin.^{[5] [6]}

• Fluclorolone acetonide
• Fluocinolone acetonide
• Triamcinolone acetonide

See also

• Acetophenide
• Acroleinide
• Aminobenzal
• Cyclopentanonide
• Pentanonide

Notes and References

1. Book: Kocieński, Philip j. . Protecting Groups . 1994 . . Foundations of Organic Chemistry Series . 3.2.2: Diol Protecting Groups—Acetals—Isopropylidene Acetals . 103.
2. Rychnovsky, S. D.. Rogers, B. N.. Richardson, T. I. . Configurational Assignment of Polyene Macrolide Antibiotics Using the [13c]Acetonide Analysis. Acc. Chem. Res.. 1998. 31. 9–17. 10.1021/AR960223N.
3. D-(R)-Glyceraldehyde Acetonide. Christopher R. Schmid. Jerry D. Bryant. Org. Synth.. 1995. 72. 6. 10.15227/orgsyn.072.0006.
4. L-(S)-glyceraldehyde Acetonide. Christian Hubschwerlen. Jean-luc Specklin. J. Higelin. Org. Synth.. 1995. 72. 1. 10.15227/orgsyn.072.0001.
5. Book: Medizinische Chemie. 337. Steinhilber. D. Schubert-Zsilavecz. M. Roth. HJ. Deutscher Apotheker Verlag. Stuttgart. 2005. 3-7692-3483-9. German.
6. Derendorf, H.. Hochhaus, G.. Meibohm, B.. Mollmann, H.. Barth, J.. Pharmacokinetics and Pharmacodynamics of Inhaled Corticosteroids. J. Allergy Clin. Immunol.. 1998. 101. S440-S446. 10.1016/S0091-6749(98)70156-3. free.