What molecule am I?
Eugenol is an aromatic liquid found in several natural essential oils, most abundantly in clove (Syzygium aromaticum, formerly Eugenia caryophyllata, from which it gets its name). Eugenol also occurs in allspice (Pimenta dioica), nutmeg (Myristica spp.), cinnamon (Cinnamomum spp.), and basil (Ocimum basilicum).
An early literature mention of eugenol was in 1891 US Patent 457,863 to Georges de Laire of Paris, who isomerized the molecule to isoeugenol1, which can be used to make vanillin2. In 1897, F. J. Bond and F. T. Beers at Penn State (then in State College, PA) expanded on de Laire’s work by synthesizing ester, ketone, and oxime derivatives of eugenol.
In 1919, noted chemist Rainer Ludwig Claisen of Godesberg am Rhein, Germany, described methods to make eugenol based on the rearrangement of the corresponding phenyl allyl ether. Ten years later, Hein Israël Waterman* and R. Priester at the Delft University of Technology (The Netherlands) isolated eugenol from clove oil, purified it, and verified that it was identical to the synthetic compound.3
Eugenol is the major flavor component of allspice, along with methyleugenol4, myrcene5, eucalyptol6, and β-caryophyllene7. Allspice is purported to have several health benefits, including reducing inflammation, treating nausea, preventing infection, and relieving pain, according to WebMD.
Thanksgiving brings out the best in allspice and therefore eugenol. Allspice is what makes your holiday cakes, pies, and cookies taste so good. Enjoy!
For more information, go to the ScienceDirect topics pages on eugenol and allspice and a 2022 book chapter on allspice by Yasvet Yareni Andrade Avila, Julián Cruz-Olivares, and César Pérez-Alonso.
1. CAS Reg. No. 97-54-1.
2. CAS Reg. No. 121-33-5.
3. It is curious that several references to the synthesis and reactions of eugenol appeared in the literature before its isolation as a natural product was described.—Ed .
4. CAS Reg. No. 93-15-2.
5. CAS Reg. No. 123-35-3.
6. CAS Reg. No. 470-82-6.
7. CAS Reg. No. 87-44-5.
Eugenol hazard information*
| Hazard class** | GHS code and hazard statement | |
|---|---|---|
| Acute toxicity, oral, category 4 | H302—Harmful if swallowed |  |
| Skin corrosion/irritation, category 2 | H315—Causes skin irritation | |
| Skin sensitization, category 1 | H317—May cause an allergic skin reaction | |
| Serious eye damage/eye irritation, category 2A | H319—Causes serious eye irritation | |
| Respiratory sensitization, category 1 | H334—May cause allergy or asthma symptoms or breathing difficulties if inhaled |  |
| Specific target organ toxicity, single exposure, respiratory tract irritation, category 3 | H335—May cause respiratory irritation | |
| Short-term (acute) aquatic hazard, category 2 | H401—Toxic to aquatic life | |
*Compilation of multiple safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Explanation of pictograms.
Molecules from the Journals
Benfotiamine1 is a derivative of thiamine2 (vitamin B1) that contains S-benzoyl and phosphate substituents. In the late 1950s and early 1960s, it was synthesized and developed by scientists at Sankyo (Tokyo) to create a fat-soluble form of thiamine that is easily absorbed into the body. Its original use was as a dietary supplement for treating diabetic polyneuropathy.
In 2021, Margaux Sambon, Pierre Wins, and Lucien Bettendorff* at the University of Liège (Belgium) reported that bioavailable forms of thiamine, including benfotiamine, exhibited neuroprotective effects in laboratory animals. This past October, because of the increased market demand for benfotiamine, Mihaela Matache, Daniel P. Funeriu, and co-workers at the University of Bucharest described their progress toward a large-scale synthesis of the medication.
Dithioformic acid3 is the sulfur analogue of formic acid4. It is a solid that melts at 55–60 ºC with decomposition and has a characteristic sulfur odor. It was first described in the 1920s by Italian chemist T. G. Levi, who synthesized it by treating chloroform with potassium sulfide, then acidifying the resulting potassium salt.
Dithioformic acid has few practical uses, but it was recently discovered in outer space. Earlier this month, Arijit Manna* and Sabyasachi Pal at Midnapore City College (India) reported the use of the Atacama Large Millimeter/Submillimeter Array (ALMA) to detect rotational emission lines of dithioformic acid in hot corino object5 NGC 1333 IRAS 4A in the interstellar medium.
1. CAS Reg. No. 22457-89-2.
2. CAS Reg. No. 59-43-8.
3. CAS Reg. No. 4472-10-0.
4. CAS Reg. No. 64-18-6.
5. A hot corino object is a low-mass region that forms during the formation of solar-type protostars.
Molecules from the Journals
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Eugenol fast facts
| CAS Reg. No. | 97-53-0 |
| SciFindern name | Phenol, 2-methoxy-4-(2-propen-1-yl)- |
| Empirical formula | C10H12O2 |
| Molar mass | 164.20 g/mol |
| Appearance | Colorless to pale yellow liquid |
| Boiling point | 253 °C |
| Water solubility | 2.5 g/L (25 ºC) |
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