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Riccardin C
Riccardin C is a macrocyclic bis(bibenzyl). It is a secondary metabolite isolated from the Siberian cowslip subspecies '' Primula veris subsp. macrocalyx'', in '' Reboulia hemisphaerica'' and in the Chinese liverwort '' Plagiochasma intermedium''. In 2005, the compound was prepared by total synthesis together with the strained compound cavicularin Cavicularin is a natural phenolic secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animal ....Kostiuk, S. L., Woodcock, T., Dudin, L. F., Howes, P. D. and Harrowven, D. C. (2011), Unified Syntheses of Cavicularin and Riccardin C: Addressing the Synthesis of an Arene Adopting a Boat Configuration. Chemistry - A European Journal, 17: 10906–10915. References {{Dihydrostilbenoid Dihydrostilbenoids Macrocycles Cyclophanes Heterocyclic compounds with 5 rings Oxygen heteroc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrocycle
Macrocycles are often described as molecules and ions containing a ring of twelve or more atoms. Classical examples include the crown ethers, calixarenes, porphyrins, and cyclodextrins. Macrocycles describe a large, mature area of chemistry. Synthesis The formation of macrocycles by ring-closure is called macrocylization. Pioneering work was reported for studies on terpenoid macrocycles. The central challenge to macrocyclization is that ring-closing reactions do not favor the formation of large rings. Instead, small rings or polymers tend to form. This kinetic problem can be addressed by using high-dilution reactions, whereby intramolecular processes are favored relative to polymerizations. Some macrocyclizations are favored using template reactions. Templates are ions, molecules, surfaces etc. that bind and pre-organize compounds, guiding them toward formation of a particular ring size. The crown ethers are often generated in the presence of an alkali metal cation, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Metabolite
Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the normal growth, development, or reproduction of the organism. Instead, they generally mediate ecological interactions, which may produce a selective advantage for the organism by increasing its survivability or fecundity. Specific secondary metabolites are often restricted to a narrow set of species within a phylogenetic group. Secondary metabolites often play an important role in plant defense against herbivory and other interspecies defenses. Humans use secondary metabolites as medicines, flavourings, pigments, and recreational drugs. The term secondary metabolite was first coined by Albrecht Kossel, a 1910 Nobel Prize laureate for medicine and physiology in 1910. 30 years later a Polish botanist Friedrich Czapek described secondary metabolit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primula Veris Subsp
''Primula'' () is a genus of herbaceous flowering plants in the family Primulaceae. They include the primrose ('' P. vulgaris''), a familiar wildflower of banks and verges. Other common species are '' P. auricula'' (auricula), '' P. veris'' (cowslip), and '' P. elatior'' (oxlip). These species and many others are valued for their ornamental flowers. They have been extensively cultivated and hybridised (in the case of the primrose, for many hundreds of years). ''Primula'' are native to the temperate Northern Hemisphere, south into tropical mountains in Ethiopia, Indonesia, and New Guinea, and in temperate southern South America. Almost half of the known species are from the Himalayas. ''Primula'' has over 500 species in traditional treatments, and more if certain related genera are included within its circumscription.''Primula''. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reboulia Hemisphaerica
''Reboulia hemisphaerica'', the hemisphaeric liverwort or small mushroom-headed liverwort, is the only species of liverwort in the genus ''Reboulia''. A possible second species ''Reboulia queenslandica'' (Stephani) M. Hicks was published in 1992, but it was later determined to be a polyploid cross between two varieties of ''R. hemisphaerica'', so not a distinct species. Subsequent lists and publications do not recognize it as distinct. Riccardin C Riccardin C is a macrocyclic bis(bibenzyl). It is a secondary metabolite isolated from the Siberian cowslip subspecies '' Primula veris subsp. macrocalyx'', in '' Reboulia hemisphaerica'' and in the Chinese liverwort '' Plagiochasma intermedium'' ... is a phenolic cyclic bibenzyl secondary metabolite isolated from ''R. hemisphaerica'', as is marchantinquinone. References External links * * Marie L. Hicks. 2004. ''Bryophyte Flora of North America'' Reboulia Aytoniaceae Marchantiales genera Monotypic bryophyte genera {{Br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plagiochasma Intermedium
''Plagiochasma intermedium'' is a liverwort species in the genus '' Plagiochasma'' found in China. Riccardin C Riccardin C is a macrocyclic bis(bibenzyl). It is a secondary metabolite isolated from the Siberian cowslip subspecies '' Primula veris subsp. macrocalyx'', in '' Reboulia hemisphaerica'' and in the Chinese liverwort '' Plagiochasma intermedium'' ..., a macrocyclic bis(bibenzyl), can be found in ''P. intermedium''.Antifungal macrocyclic bis(bibenzyls) from the Chinese liverwort Ptagiochasm intermedlum L. Chun-Feng Xie, Jian-Bo Qu, Xiu-Zhen Wu, Na Liu, Mei Ji and Hong-Xiang Lou, Natural Product Research: Formerly Natural Product Letters, 2010, Volume 24, Issue 6, pages 515-520, References External links Aytoniaceae {{Bryophyte-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Synthesis
Total synthesis is the complete chemical synthesis of a complex molecule, often a natural product, from simple, commercially-available precursors. It usually refers to a process not involving the aid of biological processes, which distinguishes it from semisynthesis. Syntheses may sometimes conclude at a precursor with further known synthetic pathways to a target molecule, in which case it is known as a formal synthesis. Total synthesis target molecules can be natural products, medicinally-important active ingredients, known intermediates, or molecules of theoretical interest. Total synthesis targets can also be organometallic or inorganic, though these are rarely encountered. Total synthesis projects often require a wide diversity of reactions and reagents, and subsequently requires broad chemical knowledge and training to be successful. Often, the aim is to discover a new route of synthesis for a target molecule for which there already exist known routes. Sometimes, however, no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavicularin
Cavicularin is a natural phenolic secondary metabolite isolated from the liverwort '' Cavicularia densa''. This macrocycle is unusual because it was the first compound isolated from nature displaying optical activity solely due to the presence of planar chirality and axial chirality. The specific rotation for (+)-cavicularin is +168.2°. It is also a very strained molecule. The ''para''-substituted phenol ring is bent about 15° out of planarity, adopting a somewhat boat-like geometry. This type of angle strain in aromatic compounds is normally reserved for synthetic cyclophanes. The liverwort was obtained from Mount Ishizuchi in the district of Shikoku. The material was dried for one day, ground to a powder and 5 grams were refluxed in methanol for 4 months 'reference needed''/sup> to yield 2.5 mg (0.049%) of cavicularin after column chromatography and preparative TLC. Total synthesis In 2005 and again in 2011, the compound was prepared by total synthesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydrostilbenoids
Dihydrostilbenoids (bibenzyls) are natural phenols formed from the dihydrostilbene ( bibenzyl) backbone. Examples Dihydro-resveratrol is a natural phenol with a bibenzyl structure found in wine. It is also a metabolite of trans-resveratrol formed in the intestine by the hydrogenation of the double bond by microflora. Combretastatin and combretastatin B-1 are two dihydrostilbenoids found in ''Combretum caffrum'', an African tree. Isonotholaenic acid is another dihydrostilbenoid found in the Andean fern '' Argyrochosma nivea''. Bibenzyls ( 3,4'-dihydroxy-5,5'-dimethoxybibenzyl, 3,3'-dihydroxy-5-methoxybibenzyl ( batatasin III)) can be found in the orchid '' Bulbophyllum vaginatum''. Bis(bibenzyls) and macrocyclic bis(benzyls) can be found in bryophytes, such as the compounds plagiochin E, 13,13'-O-isoproylidenericcardin D, riccardin H, marchantin E, neomarchantin A, marchantin A and marchantin B in the Chinese liverwort ''Marchantia polymorpha''. Prenylated bibenzyls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrocycles
Macrocycles are often described as molecules and ions containing a ring of twelve or more atoms. Classical examples include the crown ethers, calixarenes, porphyrins, and cyclodextrins. Macrocycles describe a large, mature area of chemistry. Synthesis The formation of macrocycles by ring-closure is called macrocylization. Pioneering work was reported for studies on terpenoid macrocycles. The central challenge to macrocyclization is that ring-closing reactions do not favor the formation of large rings. Instead, small rings or polymers tend to form. This kinetic problem can be addressed by using high-dilution reactions, whereby intramolecular processes are favored relative to polymerizations. Some macrocyclizations are favored using template reactions. Templates are ions, molecules, surfaces etc. that bind and pre-organize compounds, guiding them toward formation of a particular ring size. The crown ethers are often generated in the presence of an alkali metal cation, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic Compounds With 5 Rings
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of heterocyclic chemistry focuses especially on unsaturated derivatives, and the preponderance of work and applications involves unstrained 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of pyridine, thiophene, pyrrole, and furan are quinol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
