Paraquat
Overview
Viologen
Viologens are toxic bipyridinium derivatives of 4,4'-bipyridyl. The name is because this class of compounds is easily reduced to the radical mono cation, which is intensely blue coloured....
, is quick-acting and non-selective, killing green plant tissue on contact. It is also toxic to human beings and animals. Research has shown that it is linked to development of Parkinson's disease
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
.
Pyridine
Pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...
is coupled with sodium in anhydrous ammonia to give 4,4'-bipyridine
4,4'-Bipyridine
4,4'-Bipyridine is a bipyridine which is mainly used as a precursor to N,N'-dimethyl-4,4'-bipyridinium [2]2+, known as paraquat. This species is electroactive, and its toxicity arises from the ability of this dication to interrupt biological electron transfer...
, which is then methylated with chloromethane
Chloromethane
Chloromethane, also called methyl chloride, R-40 or HCC 40, is a chemical compound of the group of organic compounds called haloalkanes. It was once widely used as a refrigerant. It is a colorless extremely flammable gas with a minorly sweet odor, which is, however, detected at possibly toxic levels...
to give the desired compound:
Although first synthesized in 1882, paraquat's herbicidal properties were not recognized until 1955.
Unanswered Questions
