What molecules are we?
In the late 1980s, A. Paul Schaap and co-workers at Wayne State University (Detroit) reported the synthesis of dioxetane derivatives that trigger bright chemiluminescence when activated by alkaline phosphatase enzymes (see image). These compounds came to be known as 鈥淪chaap鈥檚 dioxetanes鈥�.
One of Schaap鈥檚 compounds, 3-(2鈥�-spiroadamantane)-4-methoxy-4-(3鈥�-phosphoryloxy)phenyl-1,2-dioxetane1鈥攌nown as PPD marketed by Lumigen2 (Southfield, MI)鈥攊s of particular interest. It is stable at ambient temperature; and in 1989, Schaap*, Hashem Akhavan, and Louis J. Romano reported that it is suitable for . The same year, Irena Bronstein and co-workers at Tropix3 (Bedford, MA) described its use in . Typically, PPD鈥檚 more stable disodium salt is used in immunoassays rather than the free acid.
PPD is used in more than 2 billion chemiluminescent immunoassays per year for clinical diagnosis, food safety, pharmaceutical analysis, and environmental monitoring. In 2018, Roland Lindh at Uppsala University (Sweden) and Harvard University (Cambridge, MA) and coauthors around the world wrote a , including Schaap鈥檚 dioxetanes. The following year, Nir Hananya and Doron Shabat*4 at Tel Aviv University reported that adding an electron-withdrawing group to one of the dioxetanes .
1. SciFinder: phenol, 3-(4-methoxyspiro[1,2-dioxetane-3,2鈥�-tricyclo[3.3.1.13,7]decan]-4-yl)-, 1-(dihydrogen phosphate).
2. Now part of Beckman Coulter (Brea, CA).
3. Now part of PerkinElmer (Waltham, MA).
4. Shabat was one of the early coiners of 鈥淪chaap鈥檚 dioxetanes鈥�.
PPD hazard information
| Hazard class* | GHS code and hazard statement |
|---|---|
| Not a hazardous substance or mixture | 听 |
*Globally Harmonized System (GHS) of Classification and Labeling of Chemicals.
Molecules from the journals
Pentachloronitrobenzene1 (PCNB), also called quintozene, was first synthesized in 1868 by Emil Jungfleisch at the 脡cole Sup茅rieure de Pharmacie (Paris) via the reaction of pentachlorobenzene with fuming nitric acid. Its use as a pesticide began in the 1930s; it is marketed as a fungicide for turfgrass and some food crops. Because of its hazards to humans and the environment, the US Environmental Protection Agency proposed a in September 2022.
Pterostilbene2 (trans-3,5-dimethoxy-4-hydroxystilbene) is a natural product related to trans-resveratrol3; it is found in almonds, some berries, and grape leaves and vines. It acts as an antimicrobial in plants; but in concentrated form, it is an eye hazard and harmful to aquatic environments. In October 2022, Hao Zhang, Tian Wang, and colleagues at Nanjing Agricultural University (China) and Jiangsu Academy of Agricultural Sciences (Nanjing) reported that pterostilbene by targeting endoplasmic reticulum stress, oxidative stress, autophagy, and gut microbiota in piglets.听
1. CAS Reg. No. 82-68-8.
2. CAS Reg. No. 537-42-8.
3. CAS Reg. No. 501-36-0.
Molecules from the Journals
MOTW briefly describes noteworthy molecules that appeared in recent ACS journal articles. See this week's edition.
This molecule was suggested by a reader. We present听almost all of the molecules suggested by our readers.听If you have a molecule you would like us to consider, please send us a message. And thank you for your interest in Molecule of the Week! 鈥擡d.
PPD fast facts
| CAS Reg. No. | 122341-56-4 |
| Empirical formula | C18H23O7P |
| Molar mass | 382.34 g/mol |
| Appearance | White crystals |
| Melting point | 鈮�250 掳C (dec., luminescence) |
| Water solubility | 630 g/L (est.) |
, the most authoritative and comprehensive source for chemical information.
Molecule of the Week needs your suggestions!
If your favorite molecule is not in our听archive, please send us a message. The molecule can be notable for its current or historical importance or for any quirky reason. Thank you!
Stay Ahead of the Chemistry Curve
Learn how ACS can help you stay ahead in the world of chemistry.
