Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Propanil: Difference between pages

| Watchedfields = changed

| verifiedrevid = 464216165

| Reference = <ref>''[[Merck Index]]'', 11th Edition, '''7814'''.</ref>

| ImageFile = 3,4-Dichloropropionanilide.svg

| ImageAlt = Skeletal formula of propanil

| ImageFile1 = File:Propanil-3D-balls.png

| ImageAlt1 = Ball and stick rendition of the propanil molecule

| PIN = ''N''-(3,4-Dichlorophenyl)propanamide

| OtherNames = ''N''-(3,4-Dichlorophenyl)propionamide

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChEBI = 34936

| CASNo =709-98-8

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = F57I4G0520

| PubChem =4933

| SMILES = Clc1ccc(NC(=O)CC)cc1Cl

| Formula =C₉H₉Cl₂NO

| MolarMass =218.08 g/mol

| Appearance =White crystalline solid (pure), Brown powder (impure)

| Density =

| MeltingPtC = 91 to 93

| MeltingPt_notes =

| BoilingPt =

| Solubility =225 ppm

| MainHazards =

| LD50 = 1384 mg/kg (rat, oral)

| FlashPt =

| AutoignitionPt =

}}

'''Propanil''' is a widely used contact [[herbicide]]. With an estimated use of about 8 million pounds in 2001, it is one of the more widely used herbicides in the United States.<ref>[http://www.epa.gov/oppbead1/pestsales/01pestsales/usage2001_2.htm 2000-2001 Pesticide Market Estimates], U.S. Environmental Protection Agency</ref> Propanil is said to be in use in approximately 400,000 acres of rice production each year.<ref>[http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=14349 ''Management of Propanil Resistant Sedges''], {{smallcaps|UC Rice Blog}} (June 19, 2014).</ref>

==Mode of action==

The principal mode of propanil's herbicidal action against weeds is inhibition of their photosynthesis and CO₂ fixation. Plants photosynthesize in two stages. In stage I photosynthetic reactions capture sunlight energy and yield molecules with high energy content. In stage II these molecules react to capture CO₂, yielding carbohydrate precursors. In the stage I reaction a chlorophyll molecule absorbs one photon (light) and loses one electron, starting an electron transport chain reaction leading to the stage II reactions. Propanil inhibits the electron transport chain reaction and its conversion of CO₂ to carbohydrate precursors. That inhibits further development of the weed.<ref>Irina V. Ustyugova, [https://books.google.com/books?id=dk9N93KhpCUC&dq=propanil+mode+of+action&pg=PA2 ''Propanil (3,4-DCPA)-induced alterations of macrophage function''] 2-3 (Ph.D. thesis 2007). See also

[https://www2.lsuagcenter.com/weedscience/pdf/AGRO4070/Handout11.pdf ''Inhibition of Photosynthesis: Inhibition at Photosystem II''] §§&nbsp;1–4.</ref>

Rice is relatively immune to propanil but most weeds are susceptible to it. The reason for the selectivity is that rice contains a high level of the enzyme aryl acylamidase (AAA), which rapidly metabolizes propanil to relatively nontoxic 3,4-dichloroaniline. Susceptible weeds lack the [[gene]](s) coding for the AAA enzyme and thus succumb to propanil. However, intensive use of propanil and [[natural selection]] have caused some weeds to become resistant to propanil.<ref>[https://books.google.com/books?id=eXVnpH5FAV0C&dq=propanil+mode+of+action&pg=PA216 {{smallcaps|Herbicide Resistance and World Grains}}] 215-16 (Stephen B. Powles & Dale L Shaner eds. 2001).</ref>

==Synthesis==

Propanil is made industrially by [[nitration]] of [[1,2-dichlorobenzene]] ('''1''') to give [[1,2-Dichloro-4-nitrobenzene|1,2-dichloro-4-nitrobenzene]] ('''2'''), followed by [[hydrogenation]] of the [[nitro group]] with [[Raney nickel]] to give [[3,4-dichloroaniline]] ('''3'''). [[Acylation]] of the [[amine]] with [[propanoyl chloride]] yields propanil ('''4''').<ref>{{cite book|last=Wyatt|first=Stuart Warren, Paul|title=Organic synthesis : the disconnection approach|year=2008|publisher=Wiley-Blackwell|location=Oxford|isbn=978-0-470-71236-8|page=25|edition=2nd}}</ref> The resulting product is white or brown crystals.<ref>[https://pubchem.ncbi.nlm.nih.gov/compound/propanil#section=Experimental-Properties Propanil] in {{smallcaps|PubChem Open Chemistry Database}}.</ref>

[[File:Propanil synthesis.svg|600px|center]]

==Patent litigation==

Propanil was the subject of several patent infringement suits. In one, ''[[Monsanto Co. v. Rohm and Haas Co.]]'',<ref>456 F.2d 592 (3d Cir. 1972).</ref> the [[United States Court of Appeals for the Third Circuit]] held that Monsanto committed fraud on the Patent Office in procuring its patent on propanil.

[[File:Compound 3,4-DCPA claimed in US Pat No. 3,382,280.gif|thumb|300px|right|Another 3,4-DCPA structural diagram showing (at far right) chemical groups involved in fraud controversy]]

Monsanto obtained the patent by providing data to the Patent Office showing that propanil "had "unusual and valuable herbicidal activity" and that its activity was "surprising" because "related compounds possess little or no herbicidal efficiency." Monsanto had conducted a number of tests and submitted test data to the Patent Office that indicated that propanil was superior to other similar chemicals, including one chemical that differed from propanil only in eliminating the CH₂ group to the left of the CH₃ group at the far right of the diagram shown at above right. (The two chemicals are so-called adjacent [[Homologous series|homologues]].)

But Monsanto had withheld data on those tests that showed that other similar compounds also had herbicidal activity similar to that of propanil. The court said that this amounted to a misrepresentation and Monsanto was not entitled to a patent, so that the patent was invalid or unenforceable. In an earlier case, however, a judge had accepted Monsanto's argument that Monsanto "did nothing more than put their best foot forward" with the Patent Office.<ref>See 456 F.2d at 597 n.4.</ref>

==References==

{{reflist}}

==External links==

* {{PPDB|545}}

{{herbicides}}

[[Category:Herbicides]]

[[Category:Chlorobenzene derivatives]]

[[Category:Anilides]]