What molecule am I?
Borneol is a chiral bicyclic alcohol that exists in nature as two enantiomers, (鈥�)- or L-borneol (shown) and (+)- or D-borneol1. Along with former Molecules of the Week eucalyptol (aka 1,8-cineole), camphor, and 伪-辫颈苍别苍别, (鈥�)-borneol is a principal component of the oil and leaves of the herb rosemary (Salvia rosmarinus, formerly Rosmarinus officinalis).
Borneol was known as early as 1842, when French chemist Charles Fr茅d茅ric Gerhardt identified it and named it 鈥渃amphre de Born茅o鈥�, or 鈥淏orneo camphor鈥�. In the 1870s, English chemist Henry E. Armstrong and others measured the properties and reactions of borneol (which he called 鈥渃amphol鈥�) and related compounds. The 19th century chemists did not realize that borneol existed in two isomers and their publications are listed under racemic borneol2.
Borneol can be oxidized to camphor by treating it with sodium hypochlorite and other oxidizing agents. But when camphor is reduced to borneol (e.g., with sodium borohydride), the main product is borneol鈥檚 positional isomer isoborneol3. As seen in the fast facts table, (鈥�)-borneol鈥檚 melting and boiling temperatures are very close to each other. As a result, when the compound is heated up to 鈮�207 掳C, it melts and sublimes.
All of which brings us back to rosemary, which you might use 聽to season stuffing and vegetables for your Thanksgiving dinner. According to S. Kokkini, R. Karousou, and E. Hanlidou at Aristotle University (Thessaloniki, Greece) in the second edition of the Encyclopedia of Food Sciences and Nutrition, 鈥淸Rosemary oils] with a decreased amount of 伪-辫颈苍别苍别 and camphor and .鈥�
For more information on rosemary and borneol, see the .
1. CAS Reg. No. 464-43-7.
2. CAS Reg. No. 507-70-0.
3. CAS Reg. No. 124-76-5 (racemic).
(鈥�)-Borneol聽hazard information*
| Hazard class** | GHS code and hazard statement | |
|---|---|---|
| Flammable solids, category 1 | H228鈥擣lammable solid |  |
| Skin corrosion/irritation, category 2 | H315鈥擟auses skin irritation |  |
| Skin sensitization, category 1 | H317鈥擬ay cause an allergic skin reaction | |
Serious eye damage/eye irritation, category 2A | H319鈥擟auses serious eye irritation | |
| Short-term (acute) aquatic hazard, category 3 | H402鈥擧armful to aquatic life | |
Long-term (chronic) aquatic hazard, category 3 | H412鈥擧armful to aquatic life with long-lasting effects | |
*Compilation of multiple safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals.聽.
Molecule of the Future
Explosives chemists are always looking to make materials that are safer to handle and have lower environmental impact. The current trend is toward organic compounds that contain several nitrogen atoms; these substances are targeted to replace heavy metal鈥揷ontaining explosives such as lead azide1 [Pb(N3)2].
Last March, Hongwei Yang, Chuan Xiao, Guangbin Cheng, and colleagues at Nanjing University of Science and Technology (China) and China Northern Industries Group (Nanjing), reported 2, a [5,6,5]-tricyclic bistetrazole molecule (see image) that could replace lead azide as a 鈥済reen鈥� primary explosive with good priming ability.
DTAT-K, with the chemical name 5-azido-10-nitro-bis(tetrazolo)[1,5-c:5鈥�,1鈥�-f]pyrimidine, potassium salt, was synthesized from commercially available, inexpensive 4,6-dichloro-5-nitropyrimidine3 by treating it with sodium azide and then replacing the sodium ion with potassium. The authors鈥� discovery was somewhat serendipitous because they only expected the reaction to displace the chlorine atoms on the pyrimidine ring with azide groups. The formation of the tricyclic molecule and the addition of a third azide moiety were a big surprise.
1. CAS Reg. No. 13424-46-9.
2. CAS Reg. No. 2918805-26-0.
3, CAS Reg. No. 4316-93-2.
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(鈥�)-Borneol聽fast facts
| CAS Reg. No. | 464-45-9 |
| SciFinder nomenclature | Bicyclo[2.2.1]heptan-2-ol, 1,7,7-trimethyl-, (1S,2R,4S)- |
| Empirical formula | C10H18O |
| Molar mass | 154.25 g/mol |
| Appearance | White crystals, powder, or solid |
| Melting point | 207鈥�209 掳C |
| Boiling point | 210鈥�212 掳C |
| Water solubility | 0.74 g/L (25 掳C) |
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