| 词条 | Pyrazolone |
| 释义 |
Pyrazolone is 5-membered heterocycle containing 2 adjacent nitrogen atoms. It can be viewed as a derivative of pyrazole possessing an additional keto (=O) group. Structure and synthesisPyrazolone can exist in 3 isomers: 3-pyrazolone, 4-pyrazolone, and 5-pyrazolone. These isomers can interconvert via lactam–lactim and imine–enamine tautomerism; these conversion often display photochromism. For pyrazolone derivatives, the 5-pyrazolone form can be stabilized with N-alkyl or N-aryl substituents. The synthesis of pyrazolones was first reported in 1883 by Ludwig Knorr, via a condensation reaction between ethyl acetoacetate and phenylhydrazine.[1] ApplicationsPharmaceuticalsPyrazolones are amongst the oldest synthetic pharmaceuticals, starting with the introduction of antipyrine (phenazone) in 1880's.[2][3] The compounds generally act as analgesics and include dipyrone (Metamizole), aminopyrine, ampyrone, famprofazone, morazone, nifenazone, piperylon and propyphenazone. Of these dipyrone is perhaps the most widely used.[2] DyesPyrazolone groups are present in several important dyes. They are commonly used in combination with azo groups to give a sub-family of azo dyes; sometimes referred to as azopyrazolones (tartrazine, orange B, mordant red 19, yellow 2G). LigandsPyrazolones have been studied as ligands.[4] References1. ^{{cite journal|last1=Knorr|first1=Ludwig|title=Einwirkung von Acetessigester auf Phenylhydrazin|journal=Berichte der deutschen chemischen Gesellschaft|date=July 1883|volume=16|issue=2|pages=2597–2599|doi=10.1002/cber.188301602194|language=German}} 2. ^1 {{cite journal|last1=Brogden|first1=Rex N.|title=Pyrazolone Derivatives|journal=Drugs|date=1986|volume=32|issue=Supplement 4|pages=60–70|doi=10.2165/00003495-198600324-00006}} 3. ^{{cite journal|last1=Brune|first1=Kay|title=The early history of non-opioid analgesics|journal=Acute Pain|date=December 1997|volume=1|issue=1|pages=33–40|doi=10.1016/S1366-0071(97)80033-2}} 4. ^{{cite journal|last1=CASAS|first1=J|last2=GARCIATASENDE|first2=M|last3=SANCHEZ|first3=A|last4=SORDO|first4=J|last5=TOUCEDA|first5=A|title=Coordination modes of 5-pyrazolones: A solid-state overview|journal=Coordination Chemistry Reviews|date=June 2007|volume=251|issue=11-12|pages=1561–1589|doi=10.1016/j.ccr.2007.02.010}} External links
1 : Pyrazolones |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。