Alpine borane is the commercial name for an organoboron compound that is used in organic synthesis . It is a colorless liquid, although it is usually encountered as a solution. A range of alkyl-substituted borane are specialty reagents in organic synthesis. Two such reagents that are closely related to Alpine borane are 9-BBN and diisopinocampheylborane .
15-521: This reagent is generated by treating 9-BBN with α-pinene . This sterically crowded chiral trialkylborane can stereoselectively reduce aldehydes in what is known as the Midland Alpine borane reduction , or simply the Midland reduction. Hydrolysis of the resulting borinic ester affords the alcohol: It is also effective for the stereoselective reduction of certain acetylenic ketones. The reaction
30-407: A cost-effective way of growing cells similar to those found in a multicellular organism in vitro . The cells are used for a wide variety of purposes, from testing toxicity of compounds or drugs to production of eukaryotic proteins. While immortalised cell lines often originate from a well-known tissue type, they have undergone significant mutations to become immortal. This can alter the biology of
45-470: A given biomolecule —for example a drug target —but are unlikely to be useful as drugs themselves, and are often starting points in the drug discovery process. However, many natural substances are hits in almost any assay in which they are tested, and therefore not useful as tool compounds. Medicinal chemists class them instead as pan-assay interference compounds . One example is curcumin . Immortalised cell line An immortalised cell line
60-489: A very important tool for research into the biochemistry and cell biology of multicellular organisms. Immortalised cell lines have also found uses in biotechnology . An immortalised cell line should not be confused with stem cells , which can also divide indefinitely, but form a normal part of the development of a multicellular organism. There are various immortal cell lines. Some of them are normal cell lines (e.g. derived from stem cells). Other immortalised cell lines are
75-421: Is a population of cells from a multicellular organism that would normally not proliferate indefinitely but, due to mutation , have evaded normal cellular senescence and instead can keep undergoing division. The cells can therefore be grown for prolonged periods in vitro . The mutations required for immortality can occur naturally or be intentionally induced for experimental purposes. Immortal cell lines are
90-616: Is its immortality; the cells can be grown indefinitely in culture. This simplifies analysis of the biology of cells that may otherwise have a limited lifetime. Immortalised cell lines can also be cloned, giving rise to a clonal population that can, in turn, be propagated indefinitely. This allows an analysis to be repeated many times on genetically identical cells, which is desirable for repeatable scientific experiments. The alternative, performing an analysis on primary cells from multiple tissue donors, does not have this advantage. Immortalised cell lines find use in biotechnology, where they are
105-428: Is proposed to involve formation of an adduct by coordination of the carbonyl oxygen to boron. Intramolecular hydride transfer from the pinane substituent to the carbonyl carbon ensues. Many substrates for the Midland reduction have a low steric group such as an alkyne or a nitrile so as to increase selectivity. Stereochemical control comes from coordination of the carbonyl bulky borane, followed by hydride transfer opposite
120-505: The in vitro equivalent of cancerous cells. Cancer occurs when a somatic cell that normally cannot divide undergoes mutations that cause deregulation of the normal cell cycle controls, leading to uncontrolled proliferation. Immortalised cell lines have undergone similar mutations, allowing a cell type that would normally not be able to divide to be proliferated in vitro . The origins of some immortal cell lines – for example, HeLa human cells – are from naturally occurring cancers. HeLa,
135-442: The reaction mechanism , are usually not called reactants. Similarly, catalysts are not consumed by the reaction, so they are not reactants. In biochemistry , especially in connection with enzyme -catalyzed reactions, the reactants are commonly called substrates . In organic chemistry , the term "reagent" denotes a chemical ingredient (a compound or mixture, typically of inorganic or small organic molecules) introduced to cause
150-529: The cell and must be taken into consideration in any analysis. Further, cell lines can change genetically over multiple passages, leading to phenotypic differences among isolates and potentially different experimental results depending on when and with what strain isolate an experiment is conducted. Many cell lines that are widely used for biomedical research have been contaminated and overgrown by other, more aggressive cells. For example, supposed thyroid lines were actually melanoma cells, supposed prostate tissue
165-627: The desired transformation of an organic substance. Examples include the Collins reagent , Fenton's reagent , and Grignard reagents . In analytical chemistry , a reagent is a compound or mixture used to detect the presence or absence of another substance, e.g. by a color change, or to measure the concentration of a substance, e.g. by colorimetry . Examples include Fehling's reagent , Millon's reagent , and Tollens' reagent . In commercial or laboratory preparations, reagent-grade designates chemical substances meeting standards of purity that ensure
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#1732852156380180-577: The field of biology, the biotechnology revolution in the 1980s grew from the development of reagents that could be used to identify and manipulate the chemical matter in and on cells. These reagents included antibodies ( polyclonal and monoclonal ), oligomers , all sorts of model organisms and immortalised cell lines , reagents and methods for molecular cloning and DNA replication , and many others. Tool compounds are an important class of reagent in biology. They are small molecules or biochemicals like siRNA or antibodies that are known to affect
195-528: The first immortal human cell line on record to be successfully isolated and proliferated by a laboratory, was taken from Henrietta Lacks in 1951 at Johns Hopkins Hospital in Baltimore , Maryland. Immortalised cell lines are widely used as a simple model for more complex biological systems – for example, for the analysis of the biochemistry and cell biology of mammalian (including human ) cells. The main advantage of using an immortal cell line for research
210-433: The largest group. Reagent In chemistry , a reagent ( / r i ˈ eɪ dʒ ən t / ree- AY -jənt ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction , or test if one occurs. The terms reactant and reagent are often used interchangeably, but reactant specifies a substance consumed in the course of a chemical reaction. Solvents , though involved in
225-688: The scientific precision and reliability of chemical analysis , chemical reactions or physical testing. Purity standards for reagents are set by organizations such as ASTM International or the American Chemical Society . For instance, reagent-quality water must have very low levels of impurities such as sodium and chloride ions, silica , and bacteria, as well as a very high electrical resistivity . Laboratory products which are less pure, but still useful and economical for undemanding work, may be designated as technical , practical , or crude grade to distinguish them from reagent versions. In
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