Dieldrin

Dieldrin is a chlorinated hydrocarbon originally produced in 1948 by J. Hyman & Co, Denver, as an insecticide. Dieldrin is closely related to aldrin. Aldrin reacts further to form dieldrin. Aldrin is not toxic to insects; it is oxidized in the insect to form dieldrin which is the active compound. Both dieldrin and aldrin are named after the Diels-Alder reaction which is used to form aldrin from a mixture of norbornadiene and hexachlorocyclopentadiene.

Dieldrin
IUPAC name	(1aR,2R,2aS,3S,6R,6aR,7S,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
Other names	Dieldrin, HEOD
Identifiers
CAS number	60-57-1
PubChem	969491
KEGG	C13718
ChEBI	CHEBI:34696
SMILES	ClC5(Cl)[C@]3(Cl)C(\Cl)=C(\Cl)[C@@]5(Cl)[C@H]4[C@H]1C[C@H]([C@@H]2O[C@H]12)[C@@H]34
InChI InChI=1/C12H8Cl6O/c13-8-9(14)11(16)5-3-1-2(6-7(3)19-6)4(5)10(8,15)12(11,17)18/h2-7H,1H2/t2-,3+,4+,5-,6-,7+,10+,11-
Properties
Molecular formula	C12H8Cl6O
Molar mass	380.9 g mol-1
Appearance	colorless to light tan crystals
Density	1.75 g/cm3
Melting point	176 to 177 °C,  K,  °F
Boiling point
Solubility in water	0.02%
Hazards
Main hazards	potential carcinogen
Flash point	noncombustible
U.S. Permissible exposure limit (PEL)	TWA 0.25 mg/m3 [skin]
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Dieldrin was developed as an alternative to DDT and has proved to be a highly effective insecticide. It was very widely used during the 1950s to early 1970s. Endrin is a stereoisomer of dieldrin.

However, it is an extremely persistent organic pollutant; it does not degrade easily. Furthermore, it tends to biomagnify as it is passed along the food chain. Long-term exposure has proven toxic to a very wide range of animals including humans. For this reason it is now banned in most of the world.

It has been linked to health problems such as Parkinson's disease, breast cancer, and immune, reproductive, and nervous system damage. It can also adversely affect testicular descent in the fetus if a pregnant woman is exposed to Dieldrin.

Dieldrin is listed in the Stockholm Convention on Persistent Organic Pollutants.

Synthesis

It can be formed from the synthesis of hexachloro-1,3-cyclopentadiene with norbornadiene in a Diels-Alder reaction, followed by epoxidation of the norbornene ring.

Synthesis of Dieldrin via a Diels-Alder reaction

Dieldrin is named after Otto Paul Hermann Diels, the co-inventor of the Diels-Alder reaction.