3-Methyl-1-phenyl-5-pyrazolon Chemische Eigenschaften,Einsatz,Produktion Methoden
Beschreibung
Das 3-Methyl-1-phenyl-2-pyrazolin-5-on bildet gelbe, in Wasser schwerl?sliche Kristalle. Der Stoff wird in der chemischen Industrie zur Herstellung von Pyrazolonfarbstoffen und pharmazeutischen Produkten (Antipyretika) verwendet.
Synthese
In einem 250-ml-Rundkolben werden 72 ml Acetessigs?ureethylester und 34 ml 60 proz. Ethanol vorgelegt. In diese L?sung tr?gt man langsam unter ?u?erer Kühlung 55 ml Phenylhydrazin ein. Dabei darf die Temperatur zu keinem Zeitpunkt 50℃ überschreiten. Wenn das gesamte Phenylhydrazin eingetragen wurde, versieht man den Kolben mit einem Dimroth-Kühler und erhitzt das Gemisch in einem ?lbad noch 30 min zum lebhaften Sieden. Nach dem Abkühlen wird das ausgeschiedene Reaktionsprodukt abgesaugt, mit Wasser gewaschen und abschlie?end im Vakuumexsikkator getrocknet. Die Ausbeute betr?gt 90 g (93 % der Theorie) eines bei 130℃ schmelzenden Produktes.
R-S?tze Betriebsanweisung:
R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
S-S?tze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S36:DE: Bei der Arbeit geeignete Schutzkleidung tragen.
Beschreibung
Edaravone was marketed in Japan for improving neurologic recovery
following acute brain infarction. Currently, several agents classified as neuroprotectants
and acting by diverse mechanisms (inhibition of glutamate release, blockade of calcium
channels, lazaroids) have been marketed for treating the outcomes of brain damage due to
trauma, ischemia or cardiac arrest. Edavarone is the first antioxidant with free radical
scavenging activity to be introduced for this pathology. This previously described molecule
(in particular as norantipyrine, one of three metabolites of antipyrine in mammals) can be
simply prepared by direct cyclization of phenylhydrazine with alkylacetoacetate. Edarevone
is a lipophilic agent, readily accessible to brain tissue, that is capable of reducing edema
in the brain following ischemia by blocking the arachidonic acid cascade triggering
peroxidative neurodegeneration. Interestingly, this agent has been shown to quench active
oxygen species in endothelial cell homogenate, as well as inhibiting in vitro lipid peroxidative disintegration of membranes, so making this compound effective during
reperfusion following ischemic injury. As an additional indication, phase III trials started with edaravone for increasing the chance of recovery after subarachnoid hemorrhage.
Chemische Eigenschaften
Off white to light yellow powder
Verwenden
Edaravone inhibits the disease activity in rheumatoid arthritis.
Definition
ChEBI: A pyrazolone that is 2,4-dihydro-3H-pyrazol-3-one which is substituted at positions 2 and 5 by phenyl and methyl groups, respectively.
Allgemeine Beschreibung
A free radical scavenger and antioxidant that reduces post-ischemic brain injury. Inhibits iron-dependent peroxidation in rat brain homogenates (IC
50 = 15 μM). Inhibits mitochondrial permeability transition pore.
Hazard
Toxic by ingestion.
Biologische Aktivit?t
A radical scavenger and antioxidant which is able to protect against the effects of ischemia, probably by inhibiting the lipoxygenase system. Protects against MPTP-induced neurotoxicity.
Sicherheitsprofil
Moderately toxic by ingestion andintraperitoneal routes. An eye irritant. When heated todecomposition it emits toxic fumes of NOx.
l?uterung methode
Crystallise the pyrazolone from hot H2O, EtOH or EtOH/water (1:1). It complexes with metals. [Veibel et al. Acta Chim Scand 6 1066 1952, Beilstein 24 II 9, 24 III/IV 71.]
3-Methyl-1-phenyl-5-pyrazolon Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte