In the chemical sciences, methylation denotes the addition of a
methyl group
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ma ...
on a
substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of
alkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecti ...
, with a methyl group replacing a
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
atom. These terms are commonly used in
chemistry,
biochemistry
Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and ...
,
soil science
Soil science is the study of soil as a natural resource on the surface of the Earth including soil formation, classification and mapping; physical, chemical, biological, and fertility properties of soils; and these properties in relation to th ...
, and the
biological sciences
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary ...
.
In
biological systems, methylation is
catalyzed
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
by
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
s; such methylation can be involved in modification of
heavy metals, regulation of
gene expression, regulation of
protein function, and
RNA processing
Transcriptional modification or co-transcriptional modification is a set of biological processes common to most eukaryotic cells by which an RNA primary transcript is chemically altered following transcription from a gene to produce a mature, f ...
. In vitro methylation of tissue samples is also one method for reducing certain
histological staining artifacts. The reverse of methylation is
demethylation Demethylation is the chemical process resulting in the removal of a methyl group (CH3) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen at ...
.
In biology
In biological systems, methylation is accomplished by enzymes. Methylation can modify heavy metals, regulate gene expression, RNA processing and protein function. It has been recognized as a key process underlying
epigenetics
In biology, epigenetics is the study of stable phenotypic changes (known as ''marks'') that do not involve alterations in the DNA sequence. The Greek prefix '' epi-'' ( "over, outside of, around") in ''epigenetics'' implies features that are ...
.
Methanogenesis
Methanogenesis, the process that generates methane from CO
2, involves a series of methylation reactions. These reactions are effected by a set of enzymes harbored by a family of anaerobic microbes.
In reverse methanogenesis, methane serves as the methylating agent.
O-methyltransferases
A wide variety of
phenols
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (— O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, . Phenolic compounds are ...
undergo O-methylation to give
anisole
Anisole, or methoxybenzene, is an organic compound with the formula CH3OC6H5. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound i ...
derivatives. This process, catalyzed by enzymes such as
caffeoyl-CoA O-methyltransferase, is a key reaction in the biosynthesis of
lignols,
percursors to
lignin, a major structural component of plants.
Plants produce flavonoids and isoflavones with methylations on hydroxyl groups, i.e.
methoxy bonds. This 5-O-methylation affects the flavonoid´s water solubility. Examples are
5-O-methylgenistein,
5-O-methylmyricetin or
5-O-methylquercetin, also known as azaleatin.
Proteins
Together with ubiquitin and phosphorylation, methylation is a major biochemical process for modifying protein function. The most prevalent protein methylations affect arginine and lysine residue of specific histones. Otherwise histidine, glutamate, asparagine, cysteine are susceptible to methylation. Some of these products include
''S''-methylcysteine, two isomers of ''N''-methylhistidine, and two isomers of ''N''-methylarginine.
Methionine synthase
Methionine synthase
Methionine synthase also known as MS, MeSe, MTR is responsible for the regeneration of methionine from homocysteine. In humans it is encoded by the ''MTR'' gene (5-methyltetrahydrofolate-homocysteine methyltransferase). Methionine synthase forms ...
regenerates
methionine (Met) from
homocysteine
Homocysteine is a non-proteinogenic α-amino acid. It is a homologue of the amino acid cysteine, differing by an additional methylene bridge (-CH2-). It is biosynthesized from methionine by the removal of its terminal Cε methyl group. In th ...
(Hcy). The overall reaction transforms
5-methyltetrahydrofolate
Levomefolic acid ( INN, also known as L-5-MTHF, L-methylfolate and L-5-methyltetrahydrofolate and (6''S'')-5-methyltetrahydrofolate, and (6''S'')-5-MTHF) is the primary biologically active form of folate used at the cellular level for DNA reprod ...
(N
5-MeTHF) into
tetrahydrofolate
Tetrahydrofolic acid (THFA), or tetrahydrofolate, is a folic acid derivative.
Metabolism
Human synthesis
Tetrahydrofolic acid is produced from dihydrofolic acid by dihydrofolate reductase. This reaction is inhibited by methotrexate.
It is co ...
(THF) while transferring a methyl group to Hcy to form Met. Methionine Synthases can be cobalamin-dependent and cobalamin-independent: Plants have both, animals depend on the methylcobalamin-dependent form.
In methylcobalamin-dependent forms of the enzyme, the reaction proceeds by two steps in a ping-pong reaction. The enzyme is initially primed into a reactive state by the transfer of a methyl group from N
5-MeTHF to Co(I) in enzyme-bound
cobalamin
Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. ...
(Cob), forming methyl-cobalamin(Me-Cob) that now contains Me-Co(III) and activating the enzyme. Then, a Hcy that has coordinated to an enzyme-bound
zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
to form a reactive thiolate reacts with the Me-Cob. The activated methyl group is transferred from Me-Cob to the Hcy thiolate, which regenerates Co(I) in Cob, and Met is released from the enzyme.
Heavy metals: arsenic, mercury, cadmium
Biomethylation is the pathway for converting some heavy elements into more mobile or more lethal derivatives that can enter the
food chain
A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), de ...
. The
biomethylation
In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These ...
of
arsenic
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, ...
compounds starts with the formation of
methanearsonate
Methylarsonic acid is an organoarsenic compound with the formula CH3AsO3H2. It is a colorless, water-soluble solid. Salts of this compound, e.g. disodium methyl arsonate, have been widely used in as herbicides and fungicides in growing cotton a ...
s. Thus, trivalent inorganic arsenic compounds are methylated to give methanearsonate.
S-adenosylmethionine is the methyl donor. The methanearsonates are the precursors to dimethylarsonates, again by the cycle of
reduction (to methylarsonous acid) followed by a second methylation.
Related pathways apply to the
biosynthesis of
methylmercury.
Epigenetic methylation
DNA/RNA methylation
DNA methylation in vertebrates typically occurs at
CpG site
The CpG sites or CG sites are regions of DNA where a cytosine nucleotide is followed by a guanine nucleotide in the linear sequence of bases along its 5' → 3' direction. CpG sites occur with high frequency in genomic regions called CpG isl ...
s (cytosine-phosphate-guanine sitesthat is, where a
cytosine
Cytosine () ( symbol C or Cyt) is one of the four nucleobases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an ...
is directly followed by a
guanine
Guanine () ( symbol G or Gua) is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine (uracil in RNA). In DNA, guanine is paired with cytosine. The guanine nucleoside is c ...
in the DNA sequence). This methylation results in the conversion of the cytosine to
5-methylcytosine. The formation of Me-CpG is
catalyzed
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
by the enzyme
DNA methyltransferase
In biochemistry, the DNA methyltransferase (DNA MTase, DNMT) family of enzymes catalyze the transfer of a methyl group to DNA. DNA methylation serves a wide variety of biological functions. All the known DNA methyltransferases use S-adenosyl m ...
. In mammals, DNA methylation is common in body cells,
and methylation of CpG sites seems to be the default.
Human DNA has about 80–90% of CpG sites methylated, but there are certain areas, known as
CpG islands
The CpG sites or CG sites are regions of DNA where a cytosine nucleotide is followed by a guanine nucleotide in the linear sequence of bases along its 5' → 3' direction. CpG sites occur with high frequency in genomic regions called CpG isl ...
, that are CG-rich (high cytosine and guanine content, made up of about 65% CG
residues), wherein none is methylated. These are associated with the
promoters of 56% of mammalian genes, including all
ubiquitously expressed genes. One to two percent of the human genome are CpG clusters, and there is an inverse relationship between CpG methylation and transcriptional activity. Methylation contributing to epigenetic inheritance can occur through either DNA methylation or protein methylation. Improper methylations of human genes can lead to disease development,
including cancer.
Similarly, RNA methylation occurs in different RNA species viz.
tRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ...
,
rRNA
Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosoma ...
,
mRNA
In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein.
mRNA is created during the ...
,
tmRNA
Transfer-messenger RNA (abbreviated tmRNA, also known as 10Sa RNA and by its genetic name SsrA) is a bacterial RNA molecule with dual tRNA-like and messenger RNA-like properties. The tmRNA forms a ribonucleoprotein complex (tmRNP) together with ...
,
snRNA
Small nuclear RNA (snRNA) is a class of small RNA molecules that are found within the splicing speckles and Cajal bodies of the cell nucleus in eukaryotic cells. The length of an average snRNA is approximately 150 nucleotides. They are transcri ...
,
snoRNA
In molecular biology, Small nucleolar RNAs (snoRNAs) are a class of small RNA molecules that primarily guide chemical modifications of other RNAs, mainly ribosomal RNAs, transfer RNAs and small nuclear RNAs. There are two main classes of snoRNA, ...
,
miRNA
MicroRNA (miRNA) are small, single-stranded, non-coding RNA molecules containing 21 to 23 nucleotides. Found in plants, animals and some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miR ...
, and viral RNA. Different catalytic strategies are employed for RNA methylation by a variety of RNA-methyltransferases. RNA methylation is thought to have existed before DNA methylation in the early forms of life evolving on earth.
N6-methyladenosine (m6A) is the most common and abundant methylation modification in RNA molecules (mRNA) present in eukaryotes. 5-methylcytosine (5-mC) also commonly occurs in various RNA molecules. Recent data strongly suggest that m6A and 5-mC RNA methylation affects the regulation of various biological processes such as RNA stability and mRNA translation, and that abnormal RNA methylation contributes to etiology of human diseases.
Protein methylation
Protein methylation typically takes place on
arginine or
lysine amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...
residues in the protein sequence.
Arginine can be methylated once (monomethylated arginine) or twice, with either both methyl groups on one terminal nitrogen (
asymmetric dimethylarginine) or one on both nitrogens (symmetric dimethylarginine), by
protein arginine methyltransferases (PRMTs). Lysine can be methylated once, twice, or three times by
lysine methyltransferases. Protein methylation has been most studied in the
histone
In biology, histones are highly basic proteins abundant in lysine and arginine residues that are found in eukaryotic cell nuclei. They act as spools around which DNA winds to create structural units called nucleosomes. Nucleosomes in turn a ...
s. The transfer of
methyl groups from
S-adenosyl methionine
''S''-Adenosyl methionine (SAM), also known under the commercial names of SAMe, SAM-e, or AdoMet, is a common cosubstrate involved in methyl group transfers, transsulfuration, and aminopropylation. Although these anabolic reactions occur throug ...
to histones is catalyzed by enzymes known as
histone methyltransferases. Histones that are methylated on certain residues can act
epigenetically
In biology, epigenetics is the study of stable phenotypic changes (known as ''marks'') that do not involve alterations in the DNA sequence. The Greek prefix '' epi-'' ( "over, outside of, around") in ''epigenetics'' implies features that are "o ...
to repress or activate gene expression.
Protein methylation is one type of
post-translational modification
Post-translational modification (PTM) is the covalent and generally enzymatic modification of proteins following protein biosynthesis. This process occurs in the endoplasmic reticulum and the golgi apparatus. Proteins are synthesized by ribos ...
.
Evolution
Methyl metabolism is very ancient and can be found in all organisms on earth, from bacteria to humans, indicating the importance of methyl metabolism for physiology.
Indeed, pharmacological inhibition of global methylation in species ranging from human, mouse, fish, fly, round worm, plant, algae and cyanobacteria causes the same effects on their biological rhythms, demonstrating conserved physiological roles of methylation during evolution.
In chemistry
The term methylation in
organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, ...
refers to the
alkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecti ...
process used to describe the delivery of a group.
Electrophilic methylation
Methylations are commonly performed using
''electrophilic'' methyl sources such as
iodomethane
Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one ...
,
dimethyl sulfate,
dimethyl carbonate
Dimethyl carbonate (DMC) is an organic compound with the formula OC(OCH3)2. It is a colourless, flammable liquid. It is classified as a carbonate ester. This compound has found use as a methylating agent and more recently as a solvent that is ...
, or
tetramethylammonium chloride
Tetramethylammonium chloride is one of the simplest quaternary ammonium salts, with four methyl groups tetrahedrally attached to the central N. The chemical formula (CH3)4N+Cl− is often abbreviated further as Me4N+Cl−. It is a hygroscopic col ...
. Less common but more powerful (and more dangerous) methylating reagents include
methyl triflate
Methyl trifluoromethanesulfonate, also commonly called methyl triflate and abbreviated MeOTf, is the organic compound with the formula CF3SO2OCH3. It is a colourless liquid which finds use in organic chemistry as a powerful methylating agent. T ...
,
diazomethane
Diazomethane is the chemical compound CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost ...
, and methyl fluorosulfonate (
magic methyl
Methyl fluorosulfonate, also known as magic methyl, is the organic compound with the formula FSO2OCH3. It is a colorless liquid that is used as a strong methylating agent in organic synthesis. Because of its extreme toxicity, it has largely been ...
). These reagents all react via S
N2
nucleophilic substitution
In chemistry, a nucleophilic substitution is a class of chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group within another electron-deficient molecule (known as the electrophile). The ...
s. For example, a
carboxylate
In organic chemistry, a carboxylate is the conjugate base of a carboxylic acid, (or ). It is an ion with negative charge.
Carboxylate salts are salts that have the general formula , where M is a metal and ''n'' is 1, 2,...; ''carboxylat ...
may be methylated on oxygen to give a methyl
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...
; an
alkoxide salt may be likewise methylated to give an
ether
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be ...
, ; or a ketone
enolate
In organic chemistry, enolates are organic anions derived from the deprotonation of carbonyl () compounds. Rarely isolated, they are widely used as reagents in the synthesis of organic compounds.
Bonding and structure
Enolate anions are electr ...
may be methylated on carbon to produce a new
ketone.
:
The
Purdie methylation is a specific for the methylation at oxygen of
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...
s using
iodomethane
Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one ...
and
silver oxide
Silver oxide is the chemical compound with the formula Ag2O. It is a fine black or dark brown powder that is used to prepare other silver compounds.
Preparation
Silver oxide can be prepared by combining aqueous solutions of silver nitrate and a ...
.
:
Eschweiler–Clarke methylation
The
Eschweiler–Clarke reaction
The Eschweiler–Clarke reaction (also called the Eschweiler–Clarke methylation) is a chemical reaction whereby a primary (or secondary) amine is methylated using excess formic acid and formaldehyde. Reductive amination reactions such as this on ...
is a method for methylation of
amine
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen
Hydrogen is the chemical element wi ...
s. This method avoids the risk of
quaternization
In organic chemistry, the Menshutkin reaction converts a tertiary amine into a quaternary ammonium salt by reaction with an alkyl halide. Similar reactions occur when tertiary phosphines are treated with alkyl halides.
The reaction is the met ...
, which occurs when amines are methylated with methyl halides.
Diazomethane and trimethylsilyldiazomethane
Diazomethane
Diazomethane is the chemical compound CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost ...
and the safer analogue
trimethylsilyldiazomethane
Trimethylsilyldiazomethane is the organosilicon compound with the formula (CH3)3SiCHN2. It is classified as a diazo compound. Trimethylsilyldiazomethane is a commercially available reagent used in organic chemistry as a methylating agent and as ...
methylate carboxylic acids, phenols, and even alcohols:
:
RCO2H + tmsCHN2 + CH3OH -> RCO2CH3 + CH3Otms + N2
The method offers the advantage that the side products are easily removed from the product mixture.
Nucleophilic methylation
Methylation sometimes involve use of
''nucleophilic'' methyl reagents. Strongly nucleophilic methylating agents include
methyllithium
Methyllithium is the simplest organolithium reagent with the empirical formula CH3Li. This s-block organometallic compound adopts an oligomeric structure both in solution and in the solid state. This highly reactive compound, invariably used in so ...
() or
Grignard reagents such as
methylmagnesium bromide (). For example, will add methyl groups to the
carbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containi ...
(C=O) of ketones and aldehyde.:
:
Milder methylating agents include
tetramethyltin,
dimethylzinc
Dimethylzinc, also known as Zinc methyl, DMZ, or DMZn is a colorless volatile liquid Zn(CH3)2, formed by the action of methyl iodide on zinc at elevated temperature or on zinc sodium alloy.
:2Zn + 2CH3I → Zn(CH3)2 + ZnI2
The sodium assists the ...
, and
trimethylaluminium
Trimethylaluminium is one of the simplest examples of an organoaluminium compound. Despite its name it has the formula Al2( CH3)6 (abbreviated as Al2Me6 or TMA), as it exists as a dimer. This colorless liquid is pyrophoric. It is an industriall ...
.
See also
Biology topics
*
Bisulfite sequencing
Bisulfite sequencing (also known as bisulphite sequencing) is the use of bisulfite treatment of DNA before routine sequencing to determine the pattern of methylation. DNA methylation was the first discovered epigenetic mark, and remains the mo ...
– the biochemical method used to determine the presence or absence of methyl groups on a DNA sequence
*
MethDB DNA Methylation Database
*
Microscale thermophoresis
Microscale thermophoresis (MST) is a technology for the biophysical analysis of interactions between biomolecules. Microscale thermophoresis is based on the detection of a temperature-induced change in fluorescence of a target as a function of th ...
– a biophysical method to determine the methylisation state of DNA
Organic chemistry topics
*
Alkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecti ...
*
Methoxy
In organic chemistry, a methoxy group is the functional group consisting of a methyl group bound to oxygen. This alkoxy group has the formula .
On a benzene ring, the Hammett equation classifies a methoxy substituent at the ''para'' position a ...
*
Titanium–zinc methylenation
*
Petasis reagent
The Petasis reagent, named after Nicos A. Petasis, is an organotitanium compound with the formula Cp2Ti(CH3)2. It is an orange-colored solid.
Preparation and use
The Petasis reagent is prepared by the salt metathesis reaction of methylmagnesium ...
*
Nysted reagent
The Nysted reagent is a reagent used in organic synthesis for the methylenation of a carbonyl group. It was discovered in 1975 by Leonard N. Nysted in Chicago, Illinois. It was originally prepared by reacting dibromomethane and activated zinc i ...
*
Wittig reaction
The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide called a Wittig reagent. Wittig reactions are most commonly used to convert aldehydes and ketones to alkenes. Mos ...
*
Tebbe's reagent
Tebbe's reagent is the organometallic compound with the formula (C5H5)2TiCH2ClAl(CH3)2. It is used in the methylenation of carbonyl compounds, that is it converts organic compounds containing the R2C=O group into the related R2C=CH2 derivative. It ...
References
External links
deltaMassesDetection of Methylations after Mass Spectrometry
{{Authority control
Epigenetics
Organic reactions
Post-translational modification