Semisynthesis, or partial chemical synthesis, is a type of chemical synthesis that uses chemical compounds isolated from natural sources 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.
Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or improved bioactivity.
A natural product is a natural compound or substance produced by a living organism—that is, found in nature. In the broadest sense, natural products include any substance produced by life. Natural products can also be prepared by chemical synthesis and have played a central role in the development of the field of organic chemistry by providing challenging synthetic targets. The term natural product has also been extended for commercial purposes to refer to cosmetics, dietary supplements, and foods produced from natural sources without added artificial ingredients.
The Weinreb ketone synthesis or Weinreb–Nahm ketone synthesis is a chemical reaction used in organic chemistry to make carbon–carbon bonds. It was discovered in 1981 by Steven M. Weinreb and Steven Nahm as a method to synthesize ketones. The original reaction involved two subsequent nucleophilic acyl substitutions: the conversion of an acid chloride with N,O-Dimethylhydroxylamine, to form a Weinreb–Nahm amide, and subsequent treatment of this species with an organometallic reagent such as a Grignard reagent or organolithium reagent. Nahm and Weinreb also reported the synthesis of aldehydes by reduction of the amide with an excess of lithium aluminum hydride.
Bohemic acid is a mixture of chemical compounds which is obtained through fermentation by actinobacteria species in the genus Actinosporangium (Actinoplanaceae). The name honors the Puccini opera La Bohème and many individual components of the acid carry the names of characters from La Bohème. Most of those components are antitumor agents and anthracycline antibiotics active against Gram-positive bacteria.
Anthony Gerard Martin Barrett FRS, FMedSci is a British chemist, and Sir Derek Barton Professor of Synthesis, Glaxo Professor of Organic Chemistry at Imperial College London. He is Director of the Wolfson Centre for Organic Chemistry in Medical Science. He was elected a fellow of the Royal Society in 1999 and Academy of Medical Sciences in 2003. He obtained a BSc as well as PhD from Imperial College London in 1973 and 1975 respectively.
Lavendamycin is a naturally occurring chemical compound discovered in fermentation broth of the soil bacterium Streptomyces lavendulae. Lavendamycin has antibiotic properties and anti-proliferative effects against several cancer cell lines. The use of lavendamycin as a cytotoxic agent in cancer therapy failed due to poor water solubility and non-specific cytotoxicity. The study of lavendamycin-based analogs designed to overcome these liabilities has been an area of research.
Oudemansin A is a natural product first isolated from the basidiomycete fungus Oudemansiella mucida. Its chemical structure was determined by X-ray crystallography in 1979 and absolute stereochemistry by total synthesis. Two closely related derivatives, oudemansin B and X have also been isolated from other basidiomycetes. They are all biologically active against many filamentous fungi and yeasts but with insufficient potency and stability to become useful commercial products. However, their discovery, together with the strobilurins led to agricultural fungicides including azoxystrobin with the same mechanism of action.
Penicillium viridicatum is a psychrophilic species of fungus in the genus, penicillic acid and citrinin. Penicillium viridicatum can spoil grapes and melons.
Streptomyces coeruleorubidus is a bacterium species from the genus of Streptomyces which has been isolated from marine sediment. Streptomyces coeruleorubidus produces the following medications: pacidamycin 1, baumycin B1, baumycin B2, baumycin C1, feudomycin A, feudomycin B, feudomycin C, ficellomycin, feudomycinone A, and rubomycin.
Doisynolic acid is a synthetic, nonsteroidal, orally active estrogen that was never marketed. The reaction of estradiol or estrone with potassium hydroxide, a strong base, results in doisynolic acid as a degradation product, which retains high estrogenic activity, and this reaction was how the drug was discovered, in the late 1930s. The drug is a highly active and potent estrogen by the oral or subcutaneous route. The reaction of equilenin or dihydroequilenin with potassium hydroxide was also found to produce bisdehydrodoisynolic acid, the levorotatory isomer of which is an estrogen with an "astonishingly" high degree of potency, while the dextrorotatory isomer is inactive. Doisynolic acid was named after Edward Adelbert Doisy, a pioneer in the field of estrogen research and one of the discoverers of estrone.
Streptomyces hawaiiensis is a bacterium species from the genus of Streptomyces which has been isolated from soil in Hawaii in the United States. Streptomyces hawaiiensis produces bryamycin and acyldepsipeptides.
Carbocyclic nucleosides are nucleoside analogues in which a methylene group has replaced the oxygen atom of the furanose ring. These analogues have the nucleobase attached at a simple alkyl carbon rather than being part of a hemiaminal ether linkage. As a result, they have increased chemical stability. They also have increased metabolic stability because they are unaffected by phosphorylases and hydrolases that cleave the glycosidic bond between the nucleobase and furanose ring of nucleosides. They retain many of the biological properties of the original nucleosides with respect to recognition by various enzymes and receptors.
Streptomyces prunicolor is a bacterium species from the genus of Streptomyces which has been isolated from soil in Russia. Streptomyces prunicolor produces Pironetin and the free radical scavengers benthocyanin A, benthocyanin B and benthocyanin C.
Streptomyces sanglieri is a bacterium species from the genus of Streptomyces which has been isolated from soil from a hay meadow. Streptomyces sanglieri produces the antibiotic lactonamycin Z.
Gougerotin is a water-soluble pyrimidine-based antibiotic which is produced by the bacteria Streptomyces graminearus and Streptomyces gougerotii. Gougerotin is named after the dermatologist Henri-Eugène Gougerot. Gougerotin has activity against Gram-positive and Gram-negative bacteria as well as against viruses.
Frenolicin B is an antibiotic and antitumor agent with the molecular formula C18H16O6 which is produced by the bacterium Streptomyces roseofulvus. Frenolicin B is a selective inhibitor of glutaredoxin 3 and peroxiredoxin 1.
Spicamycin is an antibiotic with the molecular formula C30H51N7O7 which is produced by the bacterium Streptomyces alanosinicus. Spicamycin also shows antitumor activity.
Gilvocarcin V is an antitumor agent and an antibiotic which is active against Gram-positive bacteria with the molecular formula C27H26O9.Gilvocarcin V is produced by the bacterium Streptomyces griseoflavus and other Streptomyces bacteria. Gilvocarcin V is a strong inhibitor of the DNA synthesis.
Sibiromycin is an antitumor antibiotic with the molecular formula C24H33N3O7 which is produced by the bacterium Streptosporangium sibiricum. Sibiromycin is a pyrrolobenzodiazepine.
