Adamantane

Adamantane is a colorless, crystalline chemical compound with a camphor-like odor. With a formula C₁₀H₁₆, it is the simplest diamondoid. Adamantane molecules consists of three connected cyclohexane rings arranged in the "armchair" configuration. It is unique in that it is both rigid and virtually stress-free. A boat-shaped configuration can also exist.

Adamantane is the most stable among all the isomers with formula C₁₀H₁₆, which include the somewhat similar twistane. The spatial arrangement of carbon atoms in adamantane is the same as in the diamond crystal. This motivates the name adamantane, which is derived from the Greek αδάμας (adamas, invincible). The name 'adamant' comes from the Greek adamas, meaning 'indestructible'.

The first synthesis of adamantane was reported in 1941 by Vladimir Prelog and D. R. Schaffner who obtained it by heating dicyclopentadiene in the presence of a catalyst. However, their method was not efficient for the synthesis of adamantane and other diamondoids. Nowadays, adamantane is prepared by isomerization of dicyclopentadiene under the influence of a catalyst.

Adamantane is a key raw material for the preparation of certain drugs, such as amantadine, rimantadine, and memantine. It is also used in the manufacture of certain lubricants and peptizing agents.

Chemical properties

Adamantane is a highly symmetrical molecule. The C-C-C bond angles are 109.47°, which is close to the ideal tetrahedral angle. The C-H bonds are 1.08 Å long, which is the typical length for a C-H bond. The molecule is free of torsional strain, which makes it very stable.

Biological activity

Adamantane derivatives have found application in medicine. The first adamantane derivative used as a drug was amantadine, which was introduced in the 1960s as an antiviral agent for the treatment of influenza. Other adamantane derivatives, such as rimantadine and memantine, have also been used as antiviral and neuroprotective drugs, respectively.

See also

• Diamondoid
• Dicyclopentadiene
• Amantadine
• Rimantadine
• Memantine