endrin

Endrin
IUPAC name	Mendrin, Compound 269 (1aR,2S,2aS,3S,6R,6aR,7R,7aS)-3,4,5,6,9,9-hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-dimethanonaphtho[2,3-b]oxirene
Identifiers
CAS number	[72-20-8]
SMILES	ClC1=C(Cl)[C@@]5(Cl)C(Cl)(Cl)[C@]1(Cl)[C@H]4[C@@H]3C[C@@H]([C@@H]2O[C@@H]23)[C@H]45
Properties
Molecular formula	C12H8Cl6O
Molar mass	380.91 g mol−1
Melting point	200 °C (decomposes)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Endrin is an organochloride that was primarily used as an insecticide. It is a colourless odorless solid, although commercial samples are often off-white. It is also a rodenticide. This compound became infamous as persistent organic pollutant and for this reason is banned in many countries.^[1][2]

Production and uses

Endrin is produced via a multistep route from hexachlorocyclopentadiene.^[2] Diels-Alder addition of acetylene gives an isomer of hexachloronorbornadiene. This compound undergoes a second Diels-Alder addition, this time with cyclopentadiene. The resulting polycyclic derivative is epoxidized to give endrin. Endrin is a stereoisomer of dieldrin.

The majority of endrin (about 80%) was consumed as a spray to control insect pests of cotton. It was also used on rice, to some extent on sugar cane, in a limited way on grain crops and sugar beets, and in Australia on tobacco and cole crops. It was occasionally used in orchards as a control of rodents, where it is sprayed on the ground under the trees in autumn or spring, often as a solution in mineral oil. As a seed treatment, it was used for cotton seed in the United States, and for beans seeds in Australia.

Environmental problems

The use of endrin is banned in many countries. Like related organochlorine pesticides, it is lipophilic. Thus, it tends to accumulate in fatty tissues of organisms living in water. Some estimates indicate its half-life in soil is over 10 years. In comparison with dieldrin, endrin is less persistent in the environment.

Safety

Endrin is toxic with an LD50 is 17.8 and 7.5 mg/kg (oral, rat). Acute endrin poisoning in humans affects primarily the nervous system. Food contaminated with endrin caused several clusters of poisonings worldwide, especially affecting children.^[1] Orally ingested endrin is eliminated mostly in feces.^[3] It is very toxic to aquatic organisms, namely fish, aquatic invertebrates, and phytoplankton. The U.S. EPA has set a freshwater acute criterion of 0.086ug/L and a chronic criterion of 0.036ug/L. In saltwater, the numbers are acute 0.037 and chronic 0.0023ug/L. ^[4] Human health contaminate criterion for water plus organism is 0.059ug/L. ^[5] Drinking water limits (maximum contaminant level (mcl)) is set to 2 ppb. ^[6]

References

1. ^ ^{a b} "Poison Control: Dangers of 'persistent organic pollutants' in the environment." [1]
2. ^ ^{a b} Robert L. Metcalf “Insect Control” in Ullmann’s Encyclopedia of Industrial Chemistry” Wiley-VCH, Weinheim, 2002. doi:10.1002/14356007.a14_263
3. ^ WHO report: 1970 Evaluations of some pesticide residues in food. 1970
4. ^ US EPA Criteria for Aquatic Life (pdf) [2]
5. ^ US EPA human health criteria document[3]
6. ^ US EPA Drinking water document[4]

See also

• Aldrin
• Dieldrin