Methyl in the context of Skeletal formula

In organic chemistry, an acetyl group is a functional group denoted by the chemical formula −COCH₃ and the structure −C(=O)−CH₃. It is sometimes represented by the symbol Ac (not to be confused with the element actinium). In IUPAC nomenclature, an acetyl group is called an ethanoyl group.

An acetyl group contains a methyl group (−CH₃) that is single-bonded to a carbonyl (C=O), making it an acyl group. The carbonyl center of an acyl radical has one non-bonded electron with which it forms a chemical bond to the remainder (denoted with the letter R) of the molecule.

In organic chemistry, a ketone /ˈkiːtoʊn/ 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)− (a carbon-oxygen double bond C=O). A ketone derived from an alkane is an alkanone. The simplest ketone is acetone (where R and R' are methyl), with the formula (CH₃)₂CO. Many ketones are of great importance in biology and industry. Examples include many sugars (ketoses), many steroids, e.g., testosterone, and the solvent acetone.

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 −C_nH_2n+1. A cycloalkyl group is derived from a cycloalkane by removal of a hydrogen atom from a ring and has the general formula −C_nH_2n−1.Typically an alkyl is a part of a larger molecule. In structural formulae, the symbol R is used to designate a generic (unspecified) alkyl group. The smallest alkyl group is methyl, with the formula −CH₃.

Methyl benzoate is an organic compound. It is an ester with the chemical formula C₆H₅COOCH₃, sometimes abbreviated as PhCO₂Me, where Ph and Me are phenyl and methyl, respectively. Its structure is C₆H₅−C(=O)−O−CH₃. It is a colorless liquid that is poorly soluble in water, but miscible with organic solvents. Methyl benzoate has a pleasant smell, strongly reminiscent of the fruit of the feijoa tree, and it is used in perfumery. It also finds use as a solvent and as a pesticide used to attract insects such as orchid bees.

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 is mainly made synthetically and is a precursor to other synthetic compounds. Structurally, it is an ether (−O−) with a methyl (−CH₃) and phenyl (−C₆H₅) group attached. Anisole is a standard reagent of both practical and pedagogical value.

Branched-chain fatty acids (BCFA) are usually saturated fatty acids with one or more methyl branches on the carbon chain. BCFAs are most often found in bacteria, but can be found in nattō, dairy, vernix caseosa of human infants and California sea lions where they may play a role in fostering the development of their intestinal microbiota. Another waxy animal material containing BCFAs is lanolin.

Branched chain fatty acids are considered to be responsible for the smell of mutton and higher content causes consumers to dislike the smell of lamb meat.Branched-chain fatty acids are synthesized by the branch-chain fatty acid synthesizing system.

o-Xylene (ortho-xylene) is an aromatic hydrocarbon with the formula C₆H₄(CH₃)₂, with two methyl substituents bonded to adjacent carbon atoms of a benzene ring (the ortho configuration). It is a constitutional isomer of m-xylene and p-xylene, the mixture being called xylene or xylenes. o-Xylene is a colourless slightly oily flammable liquid.

Dimethylmercury is an extremely toxic organomercury compound with the formula (CH₃)₂Hg. A volatile, flammable, dense and colorless liquid, dimethylmercury is one of the strongest known neurotoxins. Less than 0.1 mL is capable of inducing severe mercury poisoning resulting in death.

Silicone resins are a type of silicone material which is formed by branched, cage-like oligosiloxanes with the general formula of R_nSiX_mO_y, where R is a non-reactive substituent, usually methyl (Me = −CH₃) or phenyl (Ph = −C₆H₅), and X is a functional group: hydrogen (−H), hydroxyl (−OH), chlorine (−Cl) or alkoxy (−O). These groups are further condensed in many applications, to give highly crosslinked, insoluble polysiloxane networks.

When R is methyl, the four possible functional siloxane monomeric units are described as follows:

Omega−9 fatty acids (ω−9 fatty acids or n−9 fatty acids) are a family of unsaturated fatty acids which have in common a final carbon–carbon double bond in the omega−9 position; that is, the ninth bond from the methyl end of the fatty acid.

Unlike omega−3 fatty acids and omega−6 fatty acids, omega−9 fatty acids are not classed as essential fatty acids (EFA). This is both because they can be created by the human body from unsaturated fat, and are therefore not essential in the diet, and because the lack of an omega−6 double bond keeps them from participating in the reactions that form the eicosanoids.

Omega−6 fatty acids (also referred to as ω−6 fatty acids or n−6 fatty acids) are a family of polyunsaturated fatty acids (PUFA) that share a final carbon-carbon double bond in the n−6 position, that is, the sixth bond, counting from the methyl end. Health and medical organizations recommend intake of omega−6 fatty acids as part of healthful dietary patterns.

Demethylases are enzymes that remove methyl (CH₃) groups from nucleic acids, proteins (particularly histones), and other molecules. Demethylases are important epigenetic proteins, as they are responsible for transcriptional regulation of the genome by controlling the methylation of DNA and histones, and by extension, the chromatin state at specific gene loci.

Dimethylformamide, DMF is an organic compound with the chemical formula HCON(CH₃)₂. Its structure is HC(=O)−N(−CH₃)₂. Commonly abbreviated as DMF (although this initialism is sometimes used for dimethylfuran, or dimethyl fumarate), this colourless liquid is miscible with water and the majority of organic liquids. DMF is a common solvent for chemical reactions. Dimethylformamide is odorless, but technical-grade or degraded samples often have a fishy smell due to impurity of dimethylamine. Dimethylamine degradation impurities can be removed by sparging samples with an inert gas such as argon or by sonicating the samples under reduced pressure. As its name indicates, it is structurally related to formamide, having two methyl groups in the place of the two hydrogens. DMF is a polar (hydrophilic) aprotic solvent with a high boiling point. It facilitates reactions that follow polar mechanisms, such as S_N2 reactions.

Tetracyclines are a group of broad-spectrum antibiotic compounds that have a common basic structure and are either isolated directly from several species of Streptomyces bacteria or produced semi-synthetically from those isolated compounds. Tetracycline molecules comprise a linear fused tetracyclic nucleus (rings designated A, B, C and D) to which a variety of functional groups are attached. Tetracyclines are named after their four ("tetra-") hydrocarbon rings ("-cycl-") derivation ("-ine"). They are defined as a subclass of polyketides, having an octahydrotetracene-2-carboxamide skeleton and are known as derivatives of polycyclic naphthacene carboxamide.While all tetracyclines have a common structure, they differ from each other by the presence of chloro, methyl, and hydroxyl groups. These modifications do not change their broad antibacterial activity, but do affect pharmacological properties such as half-life and binding to proteins in serum.

Tetracyclines were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydiota, mycoplasmatota, rickettsiae, and protozoan parasites. Tetracycline itself was discovered later than chlortetracycline and oxytetracycline but is still considered as the parent compound for nomenclature purposes.Tetracyclines are among the cheapest classes of antibiotics available and have been used extensively in prophylaxis and in treatment of human and animal infections, as well as at subtherapeutic levels in animal feed as growth promoters.

Trimethylborane (TMB) is a toxic, pyrophoric gas with the formula B(CH₃)₃ (which can also be written as Me₃B, with Me representing methyl).