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Benzylidene
Benzylidene compounds are, formally speaking, derivatives of benzylidene, although few are prepared from the carbene. Benzylidene acetal is a protecting group in synthetic organic chemistry of the form PhCH(OR)2. For example, 4,6-O-benzylidene-glucopyranose is a glucose derivative. Benzylidene is an archaic term for compounds of the type PhCHX2 and PhCH= substituents (Ph = C6H5). For example, dibenzylideneacetone is (PhCH=CH)2CO. Benzal chloride, PhCHCl2, is alternatively named benzylidene chloride. Benzylidene is the molecule C6H5CH. It is a triplet carbene (CAS RN 3101-08-4). It is generated by irradiation of phenyldiazomethane. See also * Aurone An aurone is a heterocyclic chemical compound which is a type of flavonoid. There are two isomers of the molecule, with (''E'')- and (''Z'')-configurations. The molecule contains a benzofuran element associated with a benzylidene linked in posit ... References External links * Aromatic compounds {{aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aurone
An aurone is a heterocyclic chemical compound which is a type of flavonoid. There are two isomers of the molecule, with (''E'')- and (''Z'')-configurations. The molecule contains a benzofuran element associated with a benzylidene linked in position 2. In aurone, a chalcone-like group is closed into a 5-membered ring instead of the 6-membered ring more typical of flavonoids. Aurone derivatives Aurone forms the core for a family of derivatives which are known collectively as aurones. Aurones are plant flavonoids that provide yellow color to the flowers of some popular ornamental plants, such as snapdragon and cosmos. Aurones including 4'-chloro-2-hydroxyaurone (C15H11O3Cl) and 4'-chloroaurone (C15H9O2Cl) can also be found in the brown alga ''Spatoglossum variabile''. Most aurones are in a (''Z'')-configuration, which is the more stable configuration according to Austin Model 1 computation, but there are also some in the (''E'')-configurations such as (E)-3'-O-β-d-glucopyran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzylidene Acetal
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, ..., a benzylidene acetal is the functional group with the structural formula C6H5CH(OR)2 (R = alkyl, aryl). Benzylidene acetals are used as protecting groups in glycochemistry. These compounds can also be oxidized to carboxylic acids in order to open important biological molecules, such as glycosaminoglycans, to other routes of synthesis. They arise from the reaction of a 1,2- or 1,3- diols with benzaldehyde. Other aromatic aldehydes are also used.{{cite journal, title=Protection Of Diols With 4-(Tert-butyldimethylsilyloxy)benzylidene Acetal And Its Deprotection, authors=Hiroyuki Osajima, Hideto Fujiwara, Kentaro Okano, Hidetoshi Tokuyama, Tohru Fukuyama, journal=Org. Synth., year=2009, volume=86, page=130, doi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzal Chloride
Benzal chloride is an organic compound with the formula C6H5CHCl2. This colourless liquid is a lachrymator and is used as a building block in organic synthesis. Preparation and usage Benzal chloride is produced by the free radical chlorination of toluene, being preceded in the process by benzyl chloride (C6H5CH2Cl) and followed by benzotrichloride (C6H5CCl3): : C6H5CH3 + Cl2 → C6H5CH2Cl + HCl : C6H5CH2Cl + Cl2 → C6H5CHCl2 + HCl : C6H5CHCl2 + Cl2 → C6H5CCl3 + HCl Benzylic halides are typically strong alkylating agents, and for this reason benzal chloride is treated as a hazardous compound. Treatment of benzal chloride with sodium gives stilbene. Most benzal chloride main industrial use is as a precursor to benzaldehyde. This conversion involves hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protecting Group
A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis. In many preparations of delicate organic compounds, some specific parts of their molecules cannot survive the required reagents or chemical environments. Then, these parts, or groups, must be protected. For example, lithium aluminium hydride is a highly reactive but useful reagent capable of reducing esters to alcohols. It will always react with carbonyl groups, and this cannot be discouraged by any means. When a reduction of an ester is required in the presence of a carbonyl, the attack of the hydride on the carbonyl has to be prevented. For example, the carbonyl is converted into an acetal, which does not react with hydrides. The acetal is then called a protecting group for the carbonyl. After the step involving the hydride is complete, the acet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dibenzylideneacetone
Dibenzylideneacetone or dibenzalacetone, often abbreviated dba, is an organic compound with the formula C17H14O. It is a pale-yellow solid insoluble in water, but soluble in ethanol. It was first prepared in 1881 by the German chemist Rainer Ludwig Claisen (1851–1930) and the Swiss chemist Charles-Claude-Alexandre Claparède (14 April 1858 – 1 November 1913). Preparation The ''trans'',''trans'' isomer can be prepared in high yield and purity by condensation of benzaldehyde and acetone with sodium hydroxide in a water/ethanol medium followed by recrystallization. : This reaction, which proceeds via the intermediacy of benzylideneacetone, is often performed in organic chemistry classes, and is called Claisen-Schmidt condensation. Reactions and derivatives Prolonged exposure to sunlight initiates +2cycloadditions, converting it to a mixture of dimeric and trimeric cyclobutane cycloadducts. Uses Dibenzylideneacetone is used as a component in sunscreens and as a ligand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbene
In organic chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons. The general formula is or where the R represents substituents or hydrogen atoms. The term "carbene" may also refer to the specific compound , also called methylene, the parent hydride from which all other carbene compounds are formally derived. Carbenes are classified as either singlets or triplets, depending upon their electronic structure. Most carbenes are very short lived, although persistent carbenes are known. One well-studied carbene is dichlorocarbene , which can be generated ''in situ'' from chloroform and a strong base. Structures and bonding The two classes of carbenes are singlet and triplet carbenes. Singlet carbenes are spin-paired. In the language of valence bond theory, the molecule adopts an sp2 hybrid structure. Triplet carbenes have two unpaired electrons. Most carbenes have a nonlinear triplet ground state, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
