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Hantzsch River
Hantzsch is a surname. Notable people with the surname include: * Arthur Rudolf Hantzsch (1857–1935), German chemist ** Hantzsch–Widman nomenclature, type of systematic chemical nomenclature for naming heterocyclic parent hydrides ** Hantzsch pyridine synthesis, multi-component organic reaction between an aldehyde a β-keto ester and a nitrogen donor ** Hantzsch pyrrole synthesis, the chemical reaction of β-ketoesters with ammonia and α-haloketones to give substituted pyrroles * Bernhard Hantzsch (1875–1911), German ornithologist, Arctic researcher and writer, who discovered two Icelandic bird subspecies ** Hantzsch Island, uninhabited island in the Qikiqtaaluk Region of Nunavut, Canada named after Bernhard Hantzsch See also * Tzsch In the Latin script, pentagraphs are found primarily in Irish orthography. There is one archaic pentagraph in German orthography, which is found in the English word '' Nietzschean''. Irish ''Used between a velarized ("broad") and a palatalize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur Rudolf Hantzsch
Arthur Rudolf Hantzsch (7 March 1857 – 14 March 1935) was a German chemist. Life and work Hantzsch studied chemistry in Dresden and graduated at the University of Würzburg under Johannes Wislicenus. As a professor, he taught at the Universities of Zürich, Würzburg und Leipzig Leipzig ( , ; Upper Saxon: ) is the most populous city in the German state of Saxony. Leipzig's population of 605,407 inhabitants (1.1 million in the larger urban zone) as of 2021 places the city as Germany's eighth most populous, as .... The Hantzsch pyridine synthesis, a multi-component organic reaction, is named after him, as is the Hantzsch pyrrole synthesis. His surname is correctly pronounced /Haːntʃ/ (rhymes with cattle ranch). References 1857 births 1935 deaths 20th-century German chemists Scientists from Dresden ETH Zurich faculty 19th-century German chemists {{Germany-chemist-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hantzsch–Widman Nomenclature
In organic chemistry, Hantzsch–Widman nomenclature, also called the extended Hantzsch–Widman system (named for Arthur Rudolf Hantzsch and ), is a type of systematic chemical nomenclature used for naming heterocyclic parent hydrides having no more than ten ring members. Some common heterocyclic compounds have retained names that do not follow the Hantzsch–Widman pattern.. A Hantzsch–Widman name will always contain a prefix, which indicates the type of heteroatom present in the ring, and a stem, which indicates both the total number of atoms and the presence or absence of double bonds. The name may include more than one prefix, if more than one type of heteroatom is present; a multiplicative prefix if there are several heteroatoms of the same type; and locants to indicate the relative positions of the different atoms. Hantzsch–Widman names may be combined with other aspects of organic nomenclature, to indicate substitution or fused-ring systems. Prefixes The Hantzsch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hantzsch Pyridine Synthesis
The Hantzsch pyridine synthesis or Hantzsch dihydropyridine synthesis is a multi-component organic reaction between an aldehyde such as formaldehyde, 2 equivalents of a β-keto ester such as ethyl acetoacetate and a nitrogen donor such as ammonium acetate or ammonia. The initial reaction product is a dihydropyridine which can be oxidized in a subsequent step to a pyridine. The driving force for this second reaction step is aromatization. This reaction was reported in 1881 by Arthur Rudolf Hantzsch. A 1,4-dihydropyridine dicarboxylate is also called a 1,4-DHP compound or a Hantzsch ester. These compounds are an important class of calcium channel blockers and as such commercialized in for instance nifedipine, amlodipine or nimodipine. The reaction has been demonstrated to proceed in water as reaction solvent and with direct aromatization by ferric chloride, manganese dioxide or potassium permanganate in a one-pot synthesis. The Hantzsch dihydropyridine synthesis has been eff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hantzsch Pyrrole Synthesis
The Hantzsch Pyrrole Synthesis, named for Arthur Rudolf Hantzsch, is the chemical reaction of β-ketoesters (1) with ammonia (or primary amines) and α-haloketones (2) to give substituted pyrroles (3). Pyrroles are found in a variety of natural products with biological activity, so the synthesis of substituted pyrroles has important applications in medicinal chemistry. Alternative methods for synthesizing pyrroles exist, such as the Knorr pyrrole synthesis, Knorr Pyrrole Synthesis and Paal-Knorr Synthesis. Mechanism Below is one published mechanism for the reaction: The mechanism starts with the amine (1) attacking the β carbon of the β-ketoesters (2), and eventually forming an enamine (3). The enamine then attacks the carbonyl carbon of the α-haloketone (4). This is followed by the loss of H2O, giving an imine (5). This intermediate undergoes an intramolecular nucleophilic attack, forming a 5-membered ring (6). Finally, a hydrogen is eliminated and the pi-bonds are r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernhard Hantzsch
Bernhard Adolph Hantzsch (12 January 1875 – June 1911) was a German ornithologist, Arctic researcher, and writer, notable for his discovery of two Icelandic bird subspecies. Hantzsch was the first white man to cross Baffin Island.Anderson (1928), p. 460 Early life Hantzsch was born in Dresden, Germany the youngest son of the school master and researcher Adolf Hantzsch (1841–1920) and his wife Emma Jencke (1842–1889), niece of Johann Friedrich Jencke (1812–1893), the founder of the Dresden Institute, the first deaf institution. Hantzsch's siblings include the geographer and historian Viktor Hantzsch (1868–1910), the builder Hermann Hantzsch (1870–1945), and the clergyman Paul Kleinert's wife, Bertha Kleinert (1873–1924). He was baptised on 8 February 1875 by the deacon, Dr. Frommhold from Dresden's Anne Church ('' Annenkirche''). During the period of 1881 to 1889, he attended the second public school in Dresden. At an early age, Hantzsch spent time in Tharandt Fores ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hantzsch Island
Hantzsch Island is an uninhabited island in the Qikiqtaaluk Region of Nunavut, Canada. It is located in Frobisher Bay off the southern tip of Baffin Island's Meta Incognita Peninsula and the northeastern tip of Edgell Island. The closest community is the community of Iqaluit, northwest of Hantzsch Island. Geography The island is small and dome-shaped. Its habitat is characterized by coastal cliffs, grassy slopes, and a rugged shoreline. Fauna Hantzsch Island is a Canadian Important Bird Area (#NU025), an International Biological Program site, and a Key Migratory Terrestrial Bird Site (NU Site 49). Notable bird species include black-legged kittiwakes, thick-billed murres, northern fulmars, and other colonial waterbirds and seabirds. Beluga whales, bearded seal, ringed seal, harp seal, polar bears, and walrus frequent the area. History The island is named in honour of Bernhard Hantzsch, a German ornithologist Ornithology is a branch of zoology that concerns the "methodologic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tzsch
In the Latin script, pentagraphs are found primarily in Irish orthography. There is one archaic pentagraph in German orthography, which is found in the English word '' Nietzschean''. Irish ''Used between a velarized ("broad") and a palatalized ("slender") consonant:'' To write the sound (in Donegal, ): :, , , , and To write the sound (in Donegal, ): :, To write the sound : : and To write the sound : : ''Used between a slender and a broad consonant:'' To write the sound (in Donegal, ): : and To write the sound (in Donegal, ): : ''Used between two slender consonants:'' :To write the sound : and Dutch is used as the transcription of the Cyrillic letter Щ, representing the consonant in Russian, for example in the name ''Chroesjtsjov''. English is used in the English names '' Gaughan'' and ''Vaughan'' to represent the sound /ɔː/. French is used as the transcription of the Cyrillic letter Щ, representing the consonant in Russian, for example in the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
