Description
Pyridazine, sometimes called 1,2-diazine, is a six-membered ring containing two adjacent nitrogen atoms. Pyridazine is a privileged structure in medicinal chemistry and can be used as an isosteric replacement of phenyl or heteroaromatic rings. Pyridazines can improve the physiochemical properties of drug molecules by increasing their water solubility, participating as hydrogen bond acceptors, and have a high capacity to complex with targets due to their dipole moment. Pyridazine confers bioavailability, especially to the CNS, and can reduce toxicity. Pyridazine is a part of several drug molecules, and the pyradzine pharmacophore has led to a variety of pharmacologically active compounds.
Heterocyclic compound
Pyridazine refers to a heterocyclic azine compound containing a nitrogen hexaheterocyclic , it and pyrimidine, pyrazine are isomers of each other , it is insoluble in petroleum ether, soluble in methanol, ethanol and ether, and it can be miscible with water, benzene and dimethyl formamide immiscibility. Pyridazine is a weak base, which can form salts with picric acid, and hydrochloric acid; pyridazine is not prone to nucleophilic and electrophilic aromatic substitution reaction; it is stable to potassium permanganate; sodium or alcohols may be reduced open-chain , and converted to 1,4-diaminobutane. Pyridazine is widely used as pharmaceutical raw materials, such as long-term sulfa SMP which is pyridazine derivative, 4-amino-cinnoline which belongs to antimalarials, blood pressure drug hydralazine, etc. all use pyridazine as raw materials; it can also be used as raw material of pesticides, for the production of herbicides, "herbicide-sensitive", "Milstem", "bromine herbicide-sensitive", "Kusakira," "maleic hydrazide", "Norflurazon", "pyridate "" insecticide "," imputed phosphorus "and so on.
Synthesis and Structure
Pyridazines are heterocyclic compounds with an N-N bond in their ring structure. The pyridazine molecule is a π-deficient heteroaromatic compound similar to pyridine. Due to the presence of the π-deficient nitrogen aromatic heterocycles these compounds are more easily soluble in water when compared to other hydrocarbons. The basic aromatic ring system of pyridazine contains two adjacent nitrogen atoms.
The parent heterocycle was first prepared by oxidation of benzocinnoline to the pyridazinetetracarboxylic acid followed by decarboxylation. A better route to this otherwise esoteric compound starts with the maleic hydrazide. These heterocycles are often prepared via condensation of 1,4-diketones or 4-ketoacids with hydrazines.
Pyridazines are effective water oxidation catalysts with high efficiency turnover numbers up to 700.
Chemical Properties
Clear yellowish-brown liquid
Uses
Pyrrolo[1,2-b]pyridazine 1 is a N-bridgehead aromatic heterocycle containing two nitrogen atoms, is obtained by the condensation of pyridazine and pyrrole.
Definition
ChEBI: Pyridazine is a member of pyridazines and a diazine.
General Description
Pyridazine is a mono-basic 1,2-diazine compound, which is commonly prepared by the reaction of 1,4-dicarbonyls with hydrazines. Pyridazine ring is found in many herbicides like credazine, pyridatol and many pharmaceutical drugs like cefozopran, olaparib, talazoparib, and cadralazine.
Safety Profile
Moderately toxic by intraperitoneal route. When heated to decomposition it emits toxic vapors of NOx.
