Hydrazone on:
[Wikipedia]
[Google]
[Amazon]
Hydrazones are a class of
Hydrazones are the basis for various analyses of ketones and aldehydes. For example, dinitrophenylhydrazine coated onto a silica sorbent is the basis of an adsorption cartridge. The hydrazones are then eluted and analyzed by high-performance liquid chromatography (HPLC) using a ultraviolet, UV detector.
The compound carbonyl cyanide-p-trifluoromethoxyphenylhydrazone, carbonyl cyanide-''p''-trifluoromethoxyphenylhydrazone (abbreviated as FCCP) is used to uncouple ATP synthesis and reduction of
File:Benzophenone hydrazone-structure.png, Benzophenone hydrazone, an illustrative hydrazone
File:Carbonyl cyanide m-chlorophenyl hydrazone.svg, Carbonyl cyanide ''m''-chlorophenyl hydrazone
File:Gyromitrin.svg,
Hydrazones are a class of organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
s with the structure . They are related to ketone
In organic chemistry, a ketone is an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone ( ...
s and aldehyde
In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...
s by the replacement of the oxygen =O with the = functional group
In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...
. They are formed usually by the action of hydrazine
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...
on ketones or aldehydes.
Synthesis
Hydrazine, organohydrazines, and 1,1-diorganohydrazines react with aldehydes and ketones to give hydrazones. :
Phenylhydrazine
Phenylhydrazine is the chemical compound with the formula . It is often abbreviated as . It is also found in edible mushrooms.
Properties
Phenylhydrazine forms monoclinic prisms that melt to an oil around room temperature which may turn yellow ...
reacts with reducing sugar
A reducing sugar is any sugar that is capable of acting as a reducing agent. In an alkaline solution, a reducing sugar forms some aldehyde or ketone, which allows it to act as a reducing agent, for example in Benedict's reagent. In such a react ...
s to form hydrazones known as osazone
Osazone are a class of carbohydrate derivatives found in organic chemistry formed when reducing sugars are reacted with excess of phenylhydrazine at boiling temperatures.
Formation
Osazone formation was developed by Emil Fischer, who used t ...
s, which was developed by German chemist Emil Fischer
Hermann Emil Louis Fischer (; 9 October 1852 – 15 July 1919) was a German chemist and List of Nobel laureates in Chemistry, 1902 recipient of the Nobel Prize in Chemistry. He discovered the Fischer esterification. He also developed the Fisch ...
as a test to differentiate monosaccharide
Monosaccharides (from Greek '' monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built.
Chemically, monosaccharides are polyhy ...
s.
Uses
left, Pigment Yellow 97, a popular yellow colorant, is a hydrazone.">160px Sixteen or 16 may refer to: *16 (number) *one of the years 16 BC, AD 16, 1916, 2016 Films * '' Pathinaaru'' or ''Sixteen'', a 2010 Tamil film * ''Sixteen'' (1943 film), a 1943 Argentine film directed by Carlos Hugo Christensen * ''Sixteen'' ...oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
in oxidative phosphorylation
Oxidative phosphorylation(UK , US : or electron transport-linked phosphorylation or terminal oxidation, is the metabolic pathway in which Cell (biology), cells use enzymes to Redox, oxidize nutrients, thereby releasing chemical energy in order ...
in molecular biology
Molecular biology is a branch of biology that seeks to understand the molecule, molecular basis of biological activity in and between Cell (biology), cells, including biomolecule, biomolecular synthesis, modification, mechanisms, and interactio ...
.
Hydrazones are the basis of bioconjugation
Bioconjugation is a chemical strategy to form a stable Covalent bond, covalent link between two molecules, at least one of which is a biomolecule. Methods to conjugate biomolecules are applied in various field, including medicine, diagnostics, ...
strategies. Hydrazone-based coupling methods are used in medical biotechnology to couple drugs to targeted antibodies (see ADC), e.g. antibodies against a certain type of cancer cell. The hydrazone-based bond is stable at neutral pH (in the blood), but is rapidly destroyed in the acidic environment of lysosome
A lysosome () is a membrane-bound organelle that is found in all mammalian cells, with the exception of red blood cells (erythrocytes). There are normally hundreds of lysosomes in the cytosol, where they function as the cell’s degradation cent ...
s of the cell. The drug is thereby released in the cell, where it exerts its function.
Reactions
Hydrazones are susceptible to hydrolysis: :Alkyl
In organic chemistry, an alkyl group is an alkane missing one hydrogen.
The term ''alkyl'' is intentionally unspecific to include many possible substitutions.
An acyclic alkyl has the general formula of . A cycloalkyl group is derived from a cy ...
hydrazones are 102- to 103-fold more sensitive to hydrolysis than analogous oximes
In organic chemistry, an oxime is an organic compound belonging to the imines, with the general formula , where R is an organic side-chain and R' may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substituted ...
.
When derived from hydrazine itself, hydrazones condense with a second equivalent
Equivalence or Equivalent may refer to:
Arts and entertainment
*Album-equivalent unit, a measurement unit in the music industry
*Equivalence class (music)
*'' Equivalent VIII'', or ''The Bricks'', a minimalist sculpture by Carl Andre
*'' Equiva ...
of a carbonyl
In organic chemistry, a carbonyl group is a functional group with the formula , composed of a carbon atom double bond, double-bonded to an oxygen atom, and it is divalent at the C atom. It is common to several classes of organic compounds (such a ...
to give azines:
:
Hydrazones are intermediates in the Wolff–Kishner reduction.
Hydrazones are reactants in hydrazone iodination, the Shapiro reaction
The Shapiro reaction or tosylhydrazone decomposition is an organic reaction in which a ketone or aldehyde is converted to an alkene through an intermediate hydrazone in the presence of 2 equivalents of organolithium reagent. The reaction was disco ...
, and the Bamford–Stevens reaction to vinyl
Vinyl may refer to:
Chemistry
* Polyvinyl chloride (PVC), a particular vinyl polymer
* Vinyl cation, a type of carbocation
* Vinyl group, a broad class of organic molecules in chemistry
* Vinyl polymer, a group of polymers derived from vinyl ...
compounds. Hydrazones can also be synthesized by the Japp–Klingemann reaction via β-keto acids or β-keto-esters and aryl diazonium salts. Hydrazones are converted to azines when used in the preparation of 3,5-disubstituted 1''H''-pyrazole
Pyrazole is an organic compound with the chemical formula, formula . It is a heterocycle characterized as an azole with a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in Arene substitution pattern, ortho-substi ...
s, a reaction also well known using hydrazine hydrate
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...
. With a transition metal catalyst, hydrazones can serve as organometallic reagent surrogates to react with various electrophiles.
:
''N'',''N''-dialkylhydrazones
In ''N'',''N''-dialkylhydrazones the C=N bond can be hydrolysed, oxidised and reduced, the N–N bond can be reduced to the free amine. The carbon atom of the C=N bond can react with organometallic nucleophiles. The alpha-hydrogen atom is more acidic by 10orders of magnitude
In a ratio scale based on powers of ten, the order of magnitude is a measure of the nearness of two figures. Two numbers are "within an order of magnitude" of each other if their ratio is between 1/10 and 10. In other words, the two numbers are wi ...
compared to the ketone and therefore more nucleophilic. Deprotonation with for instance lithium diisopropylamide
Lithium diisopropylamide (commonly abbreviated LDA) is a chemical compound with the molecular formula . It is used as a strong base and has been widely utilized due to its good solubility in non-polar organic solvents and non-nucleophilic nature ...
(LDA) gives an azaenolate which can be alkylated by alkyl halides. The hydrazines SAMP and RAMP function as chiral auxiliary
In stereochemistry, a chiral auxiliary is a Stereogenic center, stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis. The chirality present in the auxil ...
.
:
Recovery of carbonyl compounds from N,N-dialkylhydrazones
Several methods are known to recover carbonyl compounds from N,N-dialkylhydrazones. Procedures include oxidative, hydrolytic or reductive cleavage conditions and can be compatible with a wide range of functional groups.Gallery
Gyromitrin
Gyromitrin is a toxin and carcinogen present in several members of the fungal genus '' Gyromitra'', like '' G. esculenta''. Its formula is . It is unstable and is easily hydrolyzed to the toxic compound monomethylhydrazine . Monomethylhydraz ...
(acetaldehyde methylformylhydrazone), a toxin
File:Dihydralazine structure.svg, Dihydralazine, an antihypertensive drug
File:NERYOZ.png, X-ray structure of DNP-derived hydrazone of benzophenone
Benzophenone is a naturally occurring organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. Benzophenone has been found in some fungi, fruits and plants, including grapes. It is a white solid with a low melting point and ros ...
. Selected parameters: C=N, 128 pm; N-N, 138 pm, N-N-C(Ar), 119 pm
See also
*Azo compound
Azo compounds are organic compounds bearing the functional group diazenyl (, in which R and R′ can be either aryl or alkyl groups).
IUPAC defines azo compounds as: "Derivatives of diazene (diimide), , wherein both hydrogens are substituted ...
*Imine
In organic chemistry, an imine ( or ) 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 bon ...
*Nitrosamine
Nitrosamines (or more formally ''N''-nitrosamines) are organic compounds produced by industrial processes. The chemical structure is , where R is usually an alkyl group. Nitrosamines have a nitroso group () that are "probable human carcinogens", ...
* Hydrogenation of carbon–nitrogen double bonds
References
{{Authority control Functional groups