Saflufenacil is the

ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

for an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

of the

pyrimidinedione Pyrimidinediones are a class of chemical compounds characterized by a pyrimidine ring substituted with two carbonyl groups. Examples include naturally occurring metabolites: drugs: * Fluorouracil * Idoxuridine * Primidone * Trifluridine Trif ...

chemical class used as an

herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...

. It acts by inhibiting the enzyme

protoporphyrinogen oxidase Protoporphyrinogen oxidase or protox is an enzyme that in humans is encoded by the ''PPOX'' gene. Protoporphyrinogen oxidase is responsible for the seventh step in biosynthesis of protoporphyrin IX. This porphyrin is the precursor to hemoglobin, ...

to control broadleaf weeds in crops including

soybeans The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu and ...

and

corn Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...

History

In 1985, chemists at the Dr R. Maag subsidiary of

Hoffmann-La Roche F. Hoffmann-La Roche AG, commonly known as Roche, is a Swiss multinational healthcare company that operates worldwide under two divisions: Pharmaceuticals and Diagnostics. Its holding company, Roche Holding AG, has shares listed on the SIX ...

filed patents to 3-aryl

uracil Uracil () (symbol U or Ura) is one of the four nucleobases in the nucleic acid RNA. The others are adenine (A), cytosine (C), and guanine (G). In RNA, uracil binds to adenine via two hydrogen bonds. In DNA, the uracil nucleobase is replaced by ...

derivatives which had herbicidal activity. The work was continued by

Ciba-Geigy Novartis AG is a Swiss-American multinational pharmaceutical corporation based in Basel, Switzerland and Cambridge, Massachusetts, United States (global research).name="novartis.com">https://www.novartis.com/research-development/research-loca ...

and further patents claiming additional

esters In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are ...

were published, including to butafenacil (CGA276854), which was marketed in 2001.

BASF BASF Societas Europaea, SE () is a German multinational corporation, multinational chemical company and the List of largest chemical producers, largest chemical producer in the world. Its headquarters is located in Ludwigshafen, Germany. The ...

scientists investigated the chemistry and patented an

analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog ...

where the carboxylic ester of butafenacil was replaced by a sulfamoyl

carboxamide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it is ...

. It was developed under the code number BAS800H and first marketed in 2008 with the

brand name A brand is a name, term, design, symbol or any other feature that distinguishes one seller's good or service from those of other sellers. Brands are used in business, marketing, and advertising for recognition and, importantly, to create an ...

Kixor.

Synthesis

As described in the BASF patent, the key step in the preparation of saflufenacil involved the reaction between a substituted

aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine In organic chemistry, an aromatic amine is an organic compound consisting of an aroma ...

and an oxazinone. 2-chloro-4-fluoro-5-aminobenzoic acid and 2-dimethylamino-4-(trifluoromethyl)-6H-1,3-oxazin-6-one were heated in acetic acid to form the ring systems of the herbicide in over 90% yield, with further standard chemical transformations to generate the final product.

Mechanism of action

Saflufenacil works by inhibiting protoporphyrinogen IX oxidase (PPO), preventing

chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...

formation, and resulting in accumulation of

protoporphyrin IX Protoporphyrin IX is an organic compound, classified as a porphyrin, that plays an important role in living organisms as a precursor to other critical compounds like heme (hemoglobin) and chlorophyll. It is a deeply colored solid that is not sol ...

which is a potent

photosensitizer Photosensitizers produce a physicochemical change in a neighboring molecule by either donating an electron to the substrate or by abstracting a hydrogen atom from the substrate. At the end of this process, the photosensitizer eventually returns to ...

. This activates oxygen, causing lipid peroxidation with rapid loss of membrane integrity and function. The effects visible on whole plants are

chlorosis In botany, chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. The affected plant has little or no ability to ...

and

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...

. In corn and some varieties of soyabean the effects are insufficient to cause serious damage, leading to useful selectivity.

Usage

Saflufenacil is registered for use in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, where the

Environmental Protection Agency A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...

(EPA) is responsible for regulating pesticides under the

Federal Insecticide, Fungicide, and Rodenticide Act The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) is a United States federal law that set up the basic U.S. system of pesticide regulation to protect applicators, consumers, and the environment. It is administered and regulated by t ...

(FIFRA), the

Food Quality Protection Act The Food Quality Protection Act (FQPA), or H.R.1627, was passed unanimously by Congress in 1996 and was signed into law by President Bill Clinton on August 3, 1996. The FQPA standardized the way the Environmental Protection Agency (EPA) would man ...

(FQPA) and the Pesticide Registration Improvement Act (PRIA). A pesticide can only be used legally according to the directions on the label that is included at the time of the sale. The herbicide controls only broadleaf weeds but is effective both pre- and post-emergence on a very wide range of these species including ''

Abutilon theophrasti ''Abutilon theophrasti'' (velvetleaf, velvet plant, velvetweed, Chinese jute, China jute, crown weed, buttonweed, lantern mallow, butterprint, pie-marker, or Indian mallow) is an annual plant in the family Malvaceae, native to southern Asia. It' ...

'', '' Acalypha virginica'', '' Acanthospermum hispidum'', ''

Amaranthus hybridus ''Amaranthus hybridus'', commonly called green amaranth, slim amaranth, smooth amaranth, smooth pigweed, or red amaranth, is a species of annual flowering plant. It is a weedy species found now over much of North America and introduced into Europ ...

'', '' Amaranthus palmeri'', '' Amaranthus powellii'', ''

Amaranthus retroflexus ''Amaranthus retroflexus'' is a species of flowering plant in the family Amaranthaceae with several common names, including red-root amaranth, redroot pigweed, red-rooted pigweed, common amaranth, pigweed amaranth, and common tumbleweed. page 47 ...

'', ''

Ambrosia artemisiifolia ''Ambrosia artemisiifolia'', with the common names common ragweed, annual ragweed, and low ragweed, is a species of the genus '' Ambrosia'' native to regions of the Americas. Taxonomy The species name, ''artemisiifolia'', is given because the le ...

'', ''

Chenopodium album ''Chenopodium album'' is a fast-growing weedy annual plant in the genus ''Chenopodium''. Though cultivated in some regions, the plant is elsewhere considered a weed. Common names include lamb's quarters, melde, goosefoot, wild spinach and fat-h ...

'', ''

Conyza canadensis ''Erigeron canadensis'' ( synonym ''Conyza canadensis'') is an annual plant native throughout most of North America and Central America. It is also widely naturalized in Eurasia and Australia. Common names include horseweed, Canadian horseweed ...

'', ''

Datura stramonium ''Datura stramonium'', known by the common names thorn apple, jimsonweed (jimson weed), devil's snare, or devil's trumpet, is a poisonous flowering plant of the nightshade family Solanaceae. It is a species belonging to the ''Datura'' genus a ...

'', ''

Galinsoga parviflora ''Galinsoga parviflora'' is a herbaceous plant in the Asteraceae (daisy) family. It has several common names including guasca ( Colombia), pacpa yuyo, paco yuyo and waskha (Peru), burrionera (Ecuador), albahaca silvestre and saetilla (Argentina), ...

'', ''

Helianthus annuus The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as b ...

'', ''

Hibiscus trionum ''Hibiscus trionum'', commonly called flower-of-an-hour, bladder hibiscus, bladder ketmia, bladder weed, modesty, puarangi, shoofly, and venice mallow, is an annual plant native to the Old World tropics and subtropics. It has spread throughout s ...

'', ''

Ipomoea hederacea ''Ipomoea hederacea'', the ivy-leaved morning glory, is a flowering plant in the Convolvulaceae, bindweed family. The species is native to tropical parts of the Americas, and has more recently been introduced to North America. It now occurs the ...

'', ''

Ipomoea purpurea ''Ipomoea purpurea'', the common morning-glory, tall morning-glory, or purple morning glory, is a species in the genus ''Ipomoea'', native to Mexico and Central America. Description Like all morning glories, the plant entwines itself around stru ...

'', ''

Kochia scoparia ''Bassia scoparia'' is a large annual herb in the family Amaranthaceae (''sensu lato'') native to Eurasia. It has been introduced to many parts of North America,

'', ''

Mollugo verticillata ''Mollugo verticillata'', the green carpetweed (also known as Indian chickweed), is a rapidly spreading annual plant from tropical Americas, America. In eastern North America, it is a common weed growing in disturbed areas. It forms a prostrate ...

'', ''

Physalis angulata ''Physalis angulata'' is an erect, herbaceous, annual plant belonging to the nightshade family Solanaceae. It reproduces by seed. Its leaves are dark green and roughly oval, often with tooth shapes around the edge. The flowers are five-sided an ...

'', '' Polygonum convolvulus'', '' Polygonum persicaria'', ''

Portulaca oleracea ''Portulaca oleracea'' (common purslane, also known as little hogweed, or pursley) is an annual (actually tropical perennial in USDA growing zones 10–11) succulent in the family Portulacaceae. Description The plant may reach in height. It ...

'', '' Richardia scabra'', '' Salsola kali'', '' Sicyos angulatus'', ''

Sinapis arvensis ''Sinapis arvensis'', the charlock mustard, field mustard, wild mustard, or charlock, is an annual or winter annual plant of the genus '' Sinapis'' in the family Brassicaceae. It is found in the fields of North Africa, Asia and Europe. ''Pieris ...

'', ''

Solanum nigrum ''Solanum nigrum'', the European black nightshade or simply black nightshade or blackberry nightshade, is a species of flowering plant in the genus ''Solanum'', native to Eurasia and introduced in the Americas, Australasia, and South Africa. Ripe ...

'', '' Stellaria media'', ''

Thlaspi arvense ''Thlaspi arvense'', known by the common name field pennycress, is a flowering plant in the cabbage family Brassicaceae. It is native to Eurasia, and is a common weed throughout much of North America and its home. Description ''Thlaspi arvense' ...

'', ''

Tribulus terrestris ''Tribulus terrestris'' is an annual plant in the caltrop family (Zygophyllaceae) widely distributed around the world. It is adapted to thrive in dry climate locations in which few other plants can survive. It is native to warm temperate and t ...

'' and ''

Xanthium strumarium ''Xanthium strumarium'' (rough cocklebur, clotbur, common cocklebur, large cocklebur, woolgarie bur) is a species of annual plants of the family Asteraceae. Some sources claim it originates in southern Europe and Asia, but has been extensively na ...

''. The product is typically used at application rates of 0.1 lb a.i. per acre and may also be applied for

crop desiccation Pre-harvest crop desiccation refers to the application of an agent to a crop just before harvest to kill the leaves and/or plants so that the crop dries out from environmental conditions ("dry-down") more quickly and evenly. In agriculture, the ter ...

pre-harvest. The estimated annual use of saflufenacil in US agriculture is mapped by the US Geological Service and shows that in 2018, the latest date for which figures are available, approximately were applied — mainly in corn and soybean. The compound is also registered for use in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

but not in the

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...

References

{{herbicides PPO herbicides Pyrimidinediones Benzamides Trifluoromethyl compounds Fluoroarenes Chloroarenes Sulfamides Isopropyl compounds