What molecule am I?
L-Thyroxine is an amino acid that is one of two hormones located in the thyroid gland; the other is triiodothyronine1. Under the name levothyroxine, it is also a manufactured drug used to treat hypothyroidism. The molecule鈥檚 enantiomer, D-thyroxine, has no pharmacological activity.
In 1915, chemist Edward. C. Kendall at the Mayo Foundation (Rochester, MN) from unspecified animals. In the following decade, Kendall wrote several more articles on the biochemistry and pharmacology of thyroxine, including the . Kendall received the Nobel Prize for Physiology or Medicine in 1950 for his research on adrenal gland hormones, not thyroid hormones.
In 1926, Charles R. Harington听at University College London . The next year, he and George Barger beginning with p-hydroxyanisole and 3,4,5-triidonitrobenzene; later in the synthesis, they introduced the tyrosine moiety.
To this day, thyroxine, familiarly known by the trade name Synthroid (Abbvie, North Chicago, IL), is the second most prescribed drug in the United States. The active ingredient is the sodium salt, not the free acid.
1. CAS Reg. No. 6893-02-3.
L-Thyroxine hazard information*
| Hazard class** | GHS code and hazard statement | |
|---|---|---|
| Acute toxicity, oral, category 4 | H302鈥擧armful if swallowed |  |
| Skin corrosion/irritation, category 2 | H315鈥擟auses skin irritation | |
| Serious eye damage/eye irritation, category 2A | H319鈥擟auses serious eye irritation | |
| Specific target organ toxicity, single exposure, respiratory tract irritation, category 3 | H335鈥擬ay cause respiratory irritation | |
*Compilation of multiple safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals.听
Molecules from the journals
1,3,3-Trinitroazetidine1 (TNAZ) is a strained molecule with a high density of nitrogen atoms. This combination gives it considerable potential energy, with a heat of decomposition of >6 J/g.
in 1989 by T. G. Archibald and coauthors at Fluorochem (Azusa, CA) and the US Naval Research Laboratory (Washington, DC). Because of its low melting point and high thermal stability as a liquid, it was proposed as a replacement for TNT2, but its high vapor pressure eliminated it as a melt-castable TNT substitute.
This past October, Jesse J. Sabatini, Corinna S. Schindler, and collaborators at the DEVCOM Army Research Laboratory (Aberdeen Proving Ground, MD) and the University of Michigan (Ann Arbor) described photochemical strategies for and other azetidines for use as melt-castable energetic compounds and propellant plasticizers.
Sesamol3 is a natural benzodioxole derivative found in sesame seeds and oil. In 1928, Dutch chemist W. Adriani , sesamolin4 and sesamin5, both of which contain two benzodioxole units.
Sesamol has been used as an antioxidant for diverse substances such as soybean oil, methyl linoleate, and phosphatidylcholine hydroperoxide. Recently, Tian Yuan and colleagues at Northwest A&F University (Yangling) and BGI Institute of Applied Agriculture (Shenzhen, both in China) reported a potentially valuable medical use of the compound.
Yuan et al. discovered that sesamol in mice. Their finding that sesamol supplementation alleviates cognitive dysfunction could lead to new treatments for Alzheimer鈥檚 disease.
1. CAS Reg. No. 97645-24-4.
2. CAS Reg. No. 118-96-7.
3. CAS Reg. No. 533-31-3.
4. CAS Reg. No. 526-07-8.
5. CAS Reg. No. 607-80-7.
Molecules from the Journals
MOTW briefly describes noteworthy molecules that appeared in recent ACS journal articles. See this week's edition.
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L-Thyroxine听Fast Facts
| CAS Reg. No. | 51-48-9 |
| SciFinder nomenclature | L-Tyrosine, O-(4-hydroxy-3,5-diiodophenyl)-3,5-diiodo- |
| Empirical formula | C15H11I4NO4 |
| Molar mass | 776.87 g/mol |
| Appearance | White to cream-colored crystals or powder |
| Melting point | 235鈥�236 掳C (dec.) |
| Water solubility | 鈮�0.2 mg/L (est.) |
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