Azines are a functional class of organic compounds with the connectivity RR'C=N-N=CRR'. These compounds are the product of the condensation of hydrazine with ketones and aldehydes, although in practice they are often made by alternative routes. Ketazines are azines derived from ketones. [1] For example, acetone azine is the simplest ketazine. Aldazines are azines derived from aldehydes. [2]
The usual method of industrial production is the peroxide process, starting from the ketone, ammonia, and hydrogen peroxide. [3]
In the laboratory, azines are typically prepared by condensation of hydrazine with two equivalents of a carbonyl. [4]
Azines are also produced when chalcone reacts with a hydrazone to produce 3,5-diphenyl-1H-pyrazole, [5] in a conversion also carried out with hydrazine hydrate. [6] [7]
Azines characteristically undergo hydrolysis to hydrazines. The reaction proceeds by the intermediacy of a hydrazone:
Azines have been used as precursors to hydrazones: [4] [8]
They are also precursors to diazo compounds. [9] [8] [10]
The coordination chemistry of azines (as ligands) has also been studied. [11] [12] [13]
Acetone is used to derivatize hydrazine into acetone azine for analysis by gas chromatography. This method is used to determine trace levels of hydrazine in drinking water [14] and pharmaceuticals. [15]
Ketazines are also important intermediates in the industrial production of hydrazine hydrate by the peroxide process. [3] In the presence of an oxidant, ammonia and ketones react to give hydrazine via ketazine:
The ketazine can be hydrolyzed to the hydrazine and regenerate the ketone:
Ketazines have been also used as sources of hydrazine produced in situ, for example in the production of herbicide precursor 1,2,4-triazole. [16]
In organic chemistry, a ketone is an organic compound with the structure R−C(=O)−R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group −C(=O)−. The simplest ketone is acetone, with the formula (CH3)2CO. Many ketones are of great importance in biology and in industry. Examples include many sugars (ketoses), many steroids, and the solvent acetone.
Hydrazine is an inorganic compound with the chemical formula N2H4. It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine hydrate.
Butanone, also known as methyl ethyl ketone (MEK) or ethyl methyl ketone, is an organic compound with the formula CH3C(O)CH2CH3. This colorless liquid ketone has a sharp, sweet odor reminiscent of acetone. It is produced industrially on a large scale, but occurs in nature only in trace amounts. It is partially soluble in water, and is commonly used as an industrial solvent. It is an isomer of another solvent, tetrahydrofuran.
Hydroxylamine is an inorganic compound with the chemical formula NH2OH. The compound is in a form of a white hygroscopic crystals. Hydroxylamine is almost always provided and used as an aqueous solution. It is consumed almost exclusively to produce Nylon-6. The oxidation of NH3 to hydroxylamine is a step in biological nitrification.
Hydrazones are a class of organic compounds with the structure R1R2C=N−NH2. They are related to ketones and aldehydes by the replacement of the oxygen =O with the =N−NH2 functional group. They are formed usually by the action of hydrazine on ketones or aldehydes.
In organic chemistry, an imine is a functional group or organic compound containing a carbon–nitrogen double bond. The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions.
Azo compounds are organic compounds bearing the functional group diazenyl.
The peroxide process is a method for the industrial production of hydrazine.
In organic chemistry, the diazo group is an organic moiety consisting of two linked nitrogen atoms at the terminal position. Overall charge-neutral organic compounds containing the diazo group bound to a carbon atom are called diazo compounds or diazoalkanes and are described by the general structural formula R2C=N+=N−. The simplest example of a diazo compound is diazomethane, CH2N2. Diazo compounds should not be confused with azo compounds or with diazonium compounds.
2,4-Dinitrophenylhydrazine (2,4-DNPH or DNPH) is the organic compound C6H3(NO2)2NHNH2. DNPH is a red to orange solid. It is a substituted hydrazine. The solid is relatively sensitive to shock and friction. For this reason DNPH is usually handled as a wet powder. DNPH is a precursor to the drug Sivifene.
Azobisisobutyronitrile (abbreviated AIBN) is an organic compound with the formula [(CH3)2C(CN)]2N2. This white powder is soluble in alcohols and common organic solvents but is insoluble in water. It is often used as a foamer in plastics and rubber and as a radical initiator.
Pyrazole is an organic compound of azole group with the formula C3H3N2H. It is a heterocycle characterized by a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in ortho-substitution. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugate acid 2.49 at 25 °C). Pyrazoles are also a class of compounds that have the ring C3N2 with adjacent nitrogen atoms. Notable drugs containing a pyrazole ring are celecoxib (celebrex) and the anabolic steroid stanozolol.
Hydrazides in organic chemistry are a class of organic compounds with the formula R−NR1−NR2R3 where R is acyl, sulfonyl, phosphoryl, phosphonyl and similar groups, R1, R2, R3 and R' are any groups. Unlike hydrazine and alkylhydrazines, hydrazides are nonbasic owing to the inductive influence of the acyl, sulfonyl, or phosphoryl substituent.
Hydrazines (R2N−NR2) are a class of chemical compounds with two nitrogen atoms linked via a covalent bond and which carry from one up to four alkyl or aryl substituents. Hydrazines can be considered as derivatives of the inorganic hydrazine (H2N−NH2), in which one or more hydrogen atoms have been replaced by hydrocarbon groups.
Semicarbazide is the chemical compound with the formula OC(NH2)(N2H3). It is a water-soluble white solid. It is a derivative of urea.
Carbohydrazide is the chemical compound with the formula OC(N2H3)2. It is a white, water-soluble solid. It decomposes upon melting. A number of carbazides are known where one or more N-H groups are replaced by other substituents. They occur widely in the drugs, herbicides, plant growth regulators, and dyestuffs.
An oxaziridine is an organic molecule that features a three-membered heterocycle containing oxygen, nitrogen, and carbon. In their largest application, oxaziridines are intermediates in the industrial production of hydrazine. Oxaziridine derivatives are also used as specialized reagents in organic chemistry for a variety of oxidations, including alpha hydroxylation of enolates, epoxidation and aziridination of olefins, and other heteroatom transfer reactions. Oxaziridines also serve as precursors to amides and participate in [3+2] cycloadditions with various heterocumulenes to form substituted five-membered heterocycles. Chiral oxaziridine derivatives effect asymmetric oxygen transfer to prochiral enolates as well as other substrates. Some oxaziridines also have the property of a high barrier to inversion of the nitrogen, allowing for the possibility of chirality at the nitrogen center.
Acetone azine is the simplest ketazine. It is an intermediate in some hydrazine manufacturing processes.
3,5-Dimethylpyrazole is an organic compound with the formula (CH3C)2CHN2H. It is one of several isomeric derivatives of pyrazole that contain two methyl substituents. The compound is unsymmetrical but the corresponding conjugate acid (pyrazolium) and conjugate base (pyrazolide) have C2v symmetry. It is a white solid that dissolves well in polar organic solvents.
Acetone hydrazone (isopropylidenehydrazine) is the product of condensation of acetone and hydrazine, as typical for hydrazone formation. It is an intermediate in the synthesis of 2-diazopropane.
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