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Partial Synthesis
Semisynthesis, or partial chemical synthesis, is a type of chemical synthesis that uses chemical compounds isolated from natural sources (such as microbial cell cultures or plant material) as the starting materials to produce novel compounds with distinct chemical and medicinal properties. The novel compounds generally have a high molecular weight or a complex molecular structure, more so than those produced by total synthesis from simple starting materials. Semisynthesis is a means of preparing many medicines more cheaply than by total synthesis since fewer chemical steps are necessary. Overview Drugs derived from natural sources are usually produced by isolation from the natural source or, as described here, by semisynthesis from such an isolated agent. From the viewpoint of chemical synthesis, living organisms are remarkable chemical factories that can easily produce structurally-complex chemical compounds by biosynthesis. In contrast, engineered chemical synthesis is necessar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Synthesis
As a topic of chemistry, chemical synthesis (or combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses, the process is reproducible and reliable. A chemical synthesis involves one or more compounds (known as '' reagents'' or ''reactants'') that will experience a transformation when subjected to certain conditions. Various reaction types can be applied to formulate a desired product. This requires mixing the compounds in a reaction vessel, such as a chemical reactor or a simple round-bottom flask. Many reactions require some form of processing (" work-up") or purification procedure to isolate the final product. The amount produced by chemical synthesis is known as the ''reaction yield''. Typically, yields are expressed as a mass in grams (in a laboratory setting) or as a percentage of the total theoretical quantity that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactant
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a substance ''consumed'' in the course of a chemical reaction. ''Solvents'', though involved in the reaction mechanism, are usually not called reactants. Similarly, ''catalysts'' are not consumed by the reaction, so they are not reactants. In biochemistry, especially in connection with enzyme-catalyzed reactions, the reactants are commonly called substrates. Definitions Organic chemistry In organic chemistry, the term "reagent" denotes a chemical ingredient (a compound or mixture, typically of inorganic or small organic molecules) introduced to cause the desired transformation of an organic substance. Examples include the Collins reagent, Fenton's reagent, and Grignard reagents. Analytical chemistry In analytical chemistry, a reagent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemurgy
Chemurgy is a branch of applied chemistry concerned with preparing industrial products from agricultural raw materials. The concept developed by the early years of the 20th century. For example, products such as brushes and motion picture film were made from cellulose. Beginning in the 1920s, William J. Hale, agricultural journalist Wheeler McMillen, and other Americans began advocating a greater link between farmers and industry. The word "chemurgy" was coined by chemist William J. Hale and first publicized in his 1934 book ''The Farm Chemurgic''. The ''Hemp Body or Soybean Car'' Automaker Henry Ford began to test farm crops for their industrial potential around 1930, and soon settled on hemp and the soybean as particularly promising (the famous Hemp Body or '' Soybean Car''). The Ford Motor Company used soybeans in such parts as gearshift knobs and horn buttons, and hemp for the body of the car. The automobile was designed to run on hemp diesel. Ford Motor Company accessed thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artemisinin
Artemisinin () and its semisynthetic derivatives are a group of drugs used in the treatment of malaria due to ''Plasmodium falciparum''. It was discovered in 1972 by Tu Youyou, who shared the 2015 Nobel Prize in Physiology or Medicine for her discovery. Artemisinin-based combination therapies (ACTs) are now standard treatment worldwide for ''P. falciparum'' malaria as well as malaria due to other species of ''Plasmodium''. Artemisinin is extracted from the plant ''Artemisia annua'', sweet wormwood, a herb employed in Chinese traditional medicine. A precursor compound can be produced using a genetically engineered yeast, which is much more efficient than using the plant. Artemisinin and its derivatives are all sesquiterpene lactones containing an unusual peroxide bridge. This endoperoxide 1,2,4-trioxane ring is responsible for their antimalarial properties. Few other natural compounds with such a peroxide bridge are known. Artemisinin and its derivatives have been used for the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artemether
Artemether is a medication used for the treatment of malaria. The injectable form is specifically used for severe malaria rather than quinine. In adults, it may not be as effective as artesunate. It is given by injection in a muscle. It is also available by mouth in combination with lumefantrine, known as artemether/lumefantrine. Artemether causes relatively few side effects. An irregular heartbeat may rarely occur. While there is evidence that use during pregnancy may be harmful in animals, there is no evidence of concern in humans. The World Health Organization (WHO) therefore recommends its use during pregnancy. It is in the artemisinin class of medication. Artemether has been studied since at least 1981, and been in medical use since 1987. It is on the World Health Organization's List of Essential Medicines. Medical uses Artemether is an antimalarial drug for uncomplicated malaria caused by '' P. falciparum'' (and chloroquine-resistant '' P. falciparum'') or chloroqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ergot
Ergot ( ) or ergot fungi refers to a group of fungi of the genus ''Claviceps''. The most prominent member of this group is ''Claviceps purpurea'' ("rye ergot fungus"). This fungus grows on rye and related plants, and produces alkaloids that can cause ergotism in humans and other mammals who consume grains contaminated with its fruiting structure (called ''ergot sclerotium''). ''Claviceps'' includes about 50 known species, mostly in the tropical regions. Economically significant species include ''C. purpurea'' (parasitic on grasses and cereals), ''C. fusiformis'' (on pearl millet, buffel grass), ''C. paspali'' (on dallis grass), ''C. africana'' (on sorghum), and ''C. lutea'' (on paspalum). ''C. purpurea'' most commonly affects outcrossing species such as rye (its most common host), as well as triticale, wheat, and barley. It affects oats only rarely. ''C. purpurea'' has at least three races or varieties, which differ in their host specificity: *G1 — land grasses of open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ergotamine
Ergotamine, sold under the brand names Cafergot (with caffeine) and Ergomar among others, is an ergopeptine and part of the ergot family of alkaloids; it is structurally and biochemically closely related to ergoline. It possesses structural similarity to several neurotransmitters, and has biological activity as a vasoconstrictor. It is used Pharmacology, medicinally for treatment of acute migraine attacks (sometimes in combination with caffeine). Medicinal usage of ergot fungus began in the 16th century to induce childbirth, yet dosage uncertainties discouraged the use. It has been used to prevent post-partum hemorrhage (bleeding after childbirth). It was first isolated from the ergot, ergot fungus by Arthur Stoll at Sandoz in 1918 and marketed as Gynergen in 1921. Biosynthesis Ergotamine is a secondary metabolite (natural product) and the principal alkaloid produced by the ergot fungus, ''Claviceps purpurea'', and related fungi in the family Clavicipitaceae. Its biosynthesis in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxus Baccata
''Taxus baccata'' is a species of evergreen tree in the family Taxaceae, native to western, central and southern Europe (including Britain and Ireland), northwest Africa, northern Iran, and southwest Asia.Rushforth, K. (1999). ''Trees of Britain and Europe''. Collins . It is the tree originally known as yew, though with other related trees becoming known, it may now be known as common yew, English yew, or European yew. It is primarily grown as an ornamental. Most parts of the plant are poisonous, with toxins that can be absorbed through inhalation and through the skin; consumption of even a small amount of the foliage can result in death. Taxonomy and naming The word ''yew'' is from Proto-Germanic ''*īwa-'', possibly originally a loanword from Gaulish ''*ivos'', compare Breton ''ivin,'' Irish '' ēo'', Welsh ''ywen'', French '' if'' (see Eihwaz for a discussion). In German it is known as ''Eibe''. ''Baccata'' is Latin for ''bearing berries''. The word ''yew'' as it was originally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paclitaxel Total Synthesis
Paclitaxel total synthesis in organic chemistry is a major ongoing research effort in the total synthesis of paclitaxel (Taxol). This diterpenoid is an important drug in the treatment of cancer but, also expensive because the compound is harvested from a scarce resource, namely the Pacific yew (''Taxus brevifolia''). Not only is the synthetic reproduction of the compound itself of great commercial and scientific importance, but it also opens the way to paclitaxel derivatives not found in nature but with greater potential. The paclitaxel molecule consists of a tetracyclic core called baccatin III and an amide tail. The core rings are conveniently called (from left to right) ring A (a cyclohexene), ring B (a cyclooctane), ring C (a cyclohexane) and ring D (an oxetane). The paclitaxel drug development process took over 40 years. The anti-tumor activity of a bark extract of the Pacific yew tree was discovered in 1963 as a follow up of a US government plant screening program already in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tigecycline
Tigecycline, sold under the brand name Tygacil, is an tetracycline antibiotic medication for a number of bacterial infections. It is a glycylcycline administered intravenously. It was developed in response to the growing rate of antibiotic resistant bacteria such as ''Staphylococcus aureus'', ''Acinetobacter baumannii'', and ''E. coli''. As a tetracycline derivative antibiotic, its structural modifications has expanded its therapeutic activity to include Gram-positive and Gram-negative organisms, including those of multi-drug resistance. It was given a U.S. Food and Drug Administration (FDA) fast-track approval and was approved on 17 June 2005. It was approved for medical use in the European Union in April 2006. It was removed from the World Health Organization's List of Essential Medicines in 2019. The World Health Organization classifies tigecycline as critically important for human medicine. Medical uses Antibacterial use Tigecycline is used to treat different kinds of ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetracycline
Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including Acne vulgaris, acne, cholera, brucellosis, plague (disease), plague, malaria, and syphilis. Common side effects include vomiting, diarrhea, rash, and loss of appetite. Other side effects include poor tooth development if used by children less than eight years of age, kidney problems, and sunburning easily. Use during pregnancy may harm the baby. It works by inhibiting protein synthesis in bacteria. Tetracycline was patented in 1953 and came into commercial use in 1978. It is on the World Health Organization's List of Essential Medicines. Tetracycline is available as a generic medication. Tetracycline was originally made from bacteria of the genus ''Streptomyces''. Medical uses Spectrum of activity Tetracyclines have a broad spectrum of antibiotic action. Originally, they possessed some level of bacteriostatic acti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlortetracycline
Chlortetracycline (trade name Aureomycin, Lederle Laboratories) is a tetracycline antibiotic, the first tetracycline to be identified. It was discovered in 1945 at Lederle Laboratories under the supervision of scientist Yellapragada Subbarow and Benjamin Minge Duggar. Duggar identified the antibiotic as the product of an actinomycete he cultured from a soil sample collected from Sanborn Field at the University of Missouri. The organism was named ''Streptomyces aureofaciens'' and the isolated drug, Aureomycin, because of their golden color. It is on the World Health Organization's List of Essential Medicines. Medical uses A combination cream with triamcinolone acetonide is available for the treatment of infected allergic dermatitis in humans. In veterinary medicine, chlortetracycline is commonly used to treat conjunctivitis in cats, dogs and horses. It is also used to treat infected wounds in cattle, sheep and pigs, and respiratory tract infections in calves, pigs and chickens. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
