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Pyrazolones
Pyrazolone is 5-membered heterocycle containing two adjacent nitrogen atoms. It can be viewed as a derivative of pyrazole possessing an additional carbonyl (C=O) group. Compounds containing this functional group are useful commercially in analgesics and dyes. Structure and synthesis Pyrazolone can exist in two isomers: 3-pyrazolone and 4-pyrazolone. These isomers can interconvert via lactam–lactim and imine–enamine tautomerism; these conversion often display photochromism. For pyrazolone derivatives, the 3-pyrazolone isomer can be stabilized with ''N''-alkyl or ''N''-aryl substituents. : The first synthesis of pyrazolones was reported in 1883 by Ludwig Knorr Ludwig Knorr (2 December 1859 – 4 June 1921) was a German chemist. Together with Carl Paal, he discovered the Paal–Knorr synthesis, and the Knorr quinoline synthesis and Knorr pyrrole synthesis are also named after him. The synthesis in 1883 ..., via a condensation reaction between ethyl acetoacetate and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminophenazone
Aminophenazone (or aminopyrine, amidopyrine, Pyramidon) is a non-narcotic analgesic substance. It is a pyrazolone and a derivative of phenazone, which also has anti-inflammatory and antipyretic properties. While inexpensive and effective, especially in the treatment of rheumatism, the drug carries a serious risk of severe and sometimes fatal side-effects, including agranulocytosis. While its production and use have been banned in many countries, including France, Thailand, India and Japan, it is still sometimes used in the developing world. A breath test with 13C-labeled aminopyrine has been used as a non-invasive measure of cytochrome P-450 metabolic activity in liver-function tests. It is also used in measuring the total body water in the human body system. History Aminophenazone was first synthesized by Friedrich Stolz and Ludwig Knorr in the late nineteenth century, and sold as an anti-fever medicine known as Pyramidon by Hoechst AG from 1897 until its eventual replacem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
