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Cinerin
The pyrethrins are a class of organic compounds normally derived from ''Chrysanthemum cinerariifolium'' that have potent insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum flowers and is often considered an organic insecticide when it is not combined with piperonyl butoxide or other synthetic adjuvants.Mader, Eric, and Nancy Lee Adamson. "Organic-Approved Pesticides."Organic-Approved Pesticides (n.d.): n. pag. The Xerxes Society. The Xerces Society for Invertebrate Conservation, Oct. 2012. Web. 10 Mar. 2015. Their insecticidal and insect-repellent properties have been known and used for thousands of years. Pyrethrins are gradually replacing organophosphates and organochlorides as the pesticides of choice as the latter compounds have been shown to have significant and persistent toxic effects to humans.They first appeared on markets in the 1900's and have been continually used since then in products such as bug bombs, bui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrethrin
The pyrethrins are a class of organic compounds normally derived from ''Chrysanthemum cinerariifolium'' that have potent Insecticide, insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum flowers and is often considered an organic horticulture, organic insecticide when it is not combined with piperonyl butoxide or other synthetic agricultural spray adjuvant, adjuvants.Mader, Eric, and Nancy Lee Adamson. "Organic-Approved Pesticides."Organic-Approved Pesticides (n.d.): n. pag. The Xerxes Society. The Xerces Society for Invertebrate Conservation, Oct. 2012. Web. 10 Mar. 2015. Their insecticidal and insect-repellent properties have been known and used for thousands of years. Pyrethrins are gradually replacing organophosphates and organochlorides as the pesticides of choice as the latter compounds have been shown to have significant and persistent toxic effects to humans.They first appeared on markets in the 1900's and have bee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrethrin II
The pyrethrins are a class of organic compounds normally derived from ''Chrysanthemum cinerariifolium'' that have potent insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum flowers and is often considered an organic insecticide when it is not combined with piperonyl butoxide or other synthetic adjuvants.Mader, Eric, and Nancy Lee Adamson. "Organic-Approved Pesticides."Organic-Approved Pesticides (n.d.): n. pag. The Xerxes Society. The Xerces Society for Invertebrate Conservation, Oct. 2012. Web. 10 Mar. 2015. Their insecticidal and insect-repellent properties have been known and used for thousands of years. Pyrethrins are gradually replacing organophosphates and organochlorides as the pesticides of choice as the latter compounds have been shown to have significant and persistent toxic effects to humans.They first appeared on markets in the 1900's and have been continually used since then in products such as bug bombs, bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrethrum
''Pyrethrum'' was a genus of several Old World plants now classified as ''Chrysanthemum'' or ''Tanacetum'' which are cultivated as ornamentals for their showy flower heads. Pyrethrum continues to be used as a common name for plants formerly included in the genus ''Pyrethrum''. Pyrethrum is also the name of a natural insecticide made from the dried flower heads of '' Chrysanthemum cinerariifolium'' and ''Chrysanthemum coccineum''. The insecticidal compounds present in these species are pyrethrins. Description Some members of the genus ''Chrysanthemum'', such as the following two, are placed in the genus ''Tanacetum'' instead by some botanists. Both genera are members of the daisy (or aster) family, Asteraceae. They are all perennial plants with a daisy-like appearance and white petals. * '' Tanacetum cinerariifolium'' is called the Dalmatian chrysanthemum, denoting its origin in that region of the Balkans (Dalmatia). It looks more like the common daisy than other pyrethrums do. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chrysanthemic Acid
Chrysanthemic acid is an organic compound that is related to a variety of natural and synthetic insecticides. It is related to the pyrethrin I and II, as well as the pyrethroids. One of the four stereoisomers, (1''R'',3''R'')- or (+)-''trans''-chrysanthemic acid (pictured), is the acid part of the ester pyrethrin I, which occurs naturally in the seed cases of ''Chrysanthemum cinerariaefolium''. Many synthetic pyrethroids, for example the allethrins, are esters of all four stereoisomers. Staudinger and Ružička named chrysanthemic acid in 1924.H. Staudinger, L. Ružička: "Insektentotende Stoffe H. Zur Konstitution der Chrysanthemummonocarbonsiiure und -dicarbonsiiure", Helv. Chem. Acta 7 (1924) 201 Biosynthesis Chrysanthemic acid is derived from its pyrophosphate ester, which in turn is produced naturally from two molecules of dimethylallyl diphosphate. Industrial synthesis Chrysanthemic acid is produced industrially in a cyclopropanation reaction of a diene In orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopropane
Cyclopropane is the cycloalkane with the molecular formula (CH2)3, consisting of three methylene groups (CH2) linked to each other to form a ring. The small size of the ring creates substantial ring strain in the structure. Cyclopropane itself is mainly of theoretical interest but many of its derivatives are of commercial or biological significance. History Cyclopropane was discovered in 1881 by August Freund, who also proposed the correct structure for the substance in his first paper. Freund treated 1,3-dibromopropane with sodium, causing an intramolecular Wurtz reaction leading directly to cyclopropane. The yield of the reaction was improved by Gustavson in 1887 with the use of zinc instead of sodium. Cyclopropane had no commercial application until Henderson and Lucas discovered its anaesthetic properties in 1929; industrial production had begun by 1936. In modern anaesthetic practice, it has been superseded by other agents. Anaesthesia Cyclopropane was introduced into cli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties. '' Nomenclature Etymology The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrethrin I
Pyrethrin I is one of the two pyrethrins, natural organic compounds with potent insecticidal activity. It is an ester of (+)-''trans''-chrysanthemic acid with (''S'')-(''Z'')-pyrethrolone. Total synthesis The synthesis of pyrethrin I involves the esterification of (+)-''trans''-chrysanthemic acid with (S)-(Z)-pyrethrolone. One synthetic method for each of these is shown in the images below. Sobti and Dev of the Malti-Chem Research Centre in Nadesari, vadodara, India published this method for chrysanthemic acid in 1974. The starting material for the synthesis uses commercially available (+)-3α, 4α-epoxycarane (1). A lactone is eventually formed and the ring is opened by the use of a Grignard reagent to give (+)-trans-chrysanthemic acid. The preparation of (''S'')-pyrethrolone is essentially a 2 step synthesis. The starting material (S)-4-hydroxy-3-methyl-2-(2-propynyl)-2-cyclopenten-1-one (7) is also commercially available as the alcohol moiety of ETOC. Tetrakis(triphenylphosphin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermann Staudinger
Hermann Staudinger (; 23 March 1881 – 8 September 1965) was a German organic chemist who demonstrated the existence of macromolecules, which he characterized as polymers. For this work he received the 1953 Nobel Prize in Chemistry. He is also known for his discovery of ketenes and of the Staudinger reaction. Staudinger, together with Leopold Ružička, also elucidated the molecular structures of pyrethrin I and II in the 1920s, enabling the development of pyrethroid insecticides in the 1960s and 1970s. Early work Staudinger was born in 1881 in Worms. Staudinger, who initially wanted to become a botanist, studied chemistry at the University of Halle, at the TH Darmstadt and at the LMU Munich. He received his "Verbandsexamen" (comparable to Master's degree) from TH Darmstadt. After receiving his Ph.D. from the University of Halle in 1903, Staudinger qualified as an academic lecturer at the University of Strasbourg in 1907. It was here that he discovered the ketenes, a family ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Napoleonic Wars
The Napoleonic Wars (1803–1815) were a series of major global conflicts pitting the French Empire and its allies, led by Napoleon I, against a fluctuating array of European states formed into various coalitions. It produced a period of French domination over most of continental Europe. The wars stemmed from the unresolved disputes associated with the French Revolution and the French Revolutionary Wars consisting of the War of the First Coalition (1792–1797) and the War of the Second Coalition (1798–1802). The Napoleonic Wars are often described as five conflicts, each termed after the coalition that fought Napoleon: the Third Coalition (1803–1806), the Fourth (1806–1807), the Fifth (1809), the Sixth (1813–1814), and the Seventh (1815) plus the Peninsular War (1807–1814) and the French invasion of Russia (1812). Napoleon, upon ascending to First Consul of France in 1799, had inherited a republic in chaos; he subsequently created a state with stable financ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Persian Powder
:''The term Persian powder can also refer to a type of dry snow in the Zagros Mountains.'' Persian powder is an insecticide powder. It is also known as Persian pellitory and insect powder. Biological pest control Persian powder is a green pesticide that has been used for centuries for the biological pest extermination of household insects, garden pests, and agricultural pests.''Bioaromatica'The history of pyrethrum It is used indoors, in gardens and the horticulture industry, and in agriculture. It is produced from the powdered flowers of certain species of pyrethrum, plants in the genera ''Chrysanthemum'' and ''Tanacetum''. In more recent times it has had formulations with brand names such as Zacherlin. Synthetic forms Pyrethroids are synthetic insecticides based on natural pyrethrum (pyrethrins), such as permethrin. A common formulation of pyrethrin is in preparations containing the synthetic chemical piperonyl butoxide: this has the effect of enhancing the toxicity to inse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
