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1,1,3,3-Tetramethylguanidine
Tetramethylguanidine is an organic compound with the formula HNC(N(CH)). This colourless liquid is a strong base, as judged by the high pK of it conjugate acid. It was originally prepared from tetramethylthiourea via ''S''-methylation and amination, but alternative methods start from cyanogen iodide. Uses Tetramethylguanidine is mainly used as a strong, non-nucleophilic base for alkylations, often as a substitute for the more expensive DBU and DBN. Since it is highly water-soluble, it is easily removed from mixtures in organic solvents. It is also used as a base-catalyst in the production of polyurethane Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethan .... References {{DEFAULTSORT:Tetramethylguanidine, 1, 1, 3, 3- Guanidines Reagents for organic chemistry Non-nucleophilic b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethylurea
Dimethylurea (DMU) (IUPAC systematic name: 1,3-Dimethylurea ) is a urea derivative and used as an intermediate in organic synthesis. It is a colorless crystalline powder with little toxicity. Uses 1,3-Dimethylurea is used for synthesis of caffeine, theophylline, pharmachemicals, textile aids, herbicides and others.http://www.inchem.org/documents/sids/sids/96311.pdf SIDS Initial Assessment Report In the textile manufacturing, textile processing industry 1,3-dimethylurea is used as intermediate for the production of formaldehyde-free easy-care textile finishing, finishing agents for textiles. The estimated world production of DMU is estimated to be less than 25,000 tons. References {{Authority control Ureas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allantoic Acid
Allantoic acid is an organic compound with the chemical formula C4H8N4O4. It is a crystalline acid obtained by hydrolysis of allantoin. In nature, allantoic acid is produced from allantoin by the enzyme allantoinase (encoded by the gene AllB (UniprotP77671 in ''Escherichia coli'' and other bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...). References Ureas Acetic acids {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carmustine
Carmustine, sold under the brand name BiCNU among others, is a medication used mainly for chemotherapy. It is a nitrogen mustard β-chloro- nitrosourea compound used as an alkylating agent. Description Carmustine is an orange-yellow solid medication used mainly for chemotherapy. It is a nitrogen mustard β-chloro- nitrosourea compound. Mechanism of action As an alkylating agent, carmustine can form interstrand crosslinks in DNA, which prevents DNA replication and DNA transcription. Uses Carmustine is used as an alkylating agent to treat several types of brain cancer including glioma, glioblastoma multiforme, medulloblastoma and astrocytoma), multiple myeloma, and lymphoma (Hodgkin's and non-Hodgkin). Carmustine is sometimes used in conjunction with alkyl guanine transferase (AGT) inhibitors, such as ''O''6-benzylguanine. The AGT-inhibitors increase the efficacy of carmustine by inhibiting the direct reversal pathway of DNA repair, which will prevent formation of the inters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noxytiolin
Noxytiolin is an anti-infective used for irrigation of the peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesoth .... References Thioureas {{blood-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanogen Iodide
Cyanogen iodide or iodine cyanide (ICN) is a pseudohalogen composed of iodine and the cyanide group. It is a highly toxic inorganic compound. It occurs as white crystals that react slowly with water to form hydrogen cyanide. Synthesis Cyanogen iodide is prepared by combining I2 and a cyanide, most commonly sodium cyanide in ice-cold water. The product is extracted with ether. :I2 + NaCN → NaI + ICN Applications Cyanogen iodide has been used in taxidermy as a preservative because of its toxicity. History Cyanogen iodide was first synthesized in 1824 by the French chemist Georges-Simon Serullas (1774–1832). Cyanogen iodide was considered one of the impurities in commercially sold iodine before the 1930s. Hazards Cyanogen iodide is toxic if inhaled or ingested and may be fatal if swallowed or absorbed through the skin. Cyanogen iodide may cause convulsions, paralysis and death from respiratory failure. It is a strong irritant and may cause burns to the eyes and skin if contac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guanidines
Guanidine is the compound with the formula HNC(NH2)2. It is a colourless solid that dissolves in polar solvents. It is a strong base that is used in the production of plastics and explosives. It is found in urine predominantly in patients experiencing renal failure. A guanidine moiety also appears in larger organic molecules, including on the side chain of arginine. Structure Guanidine can be thought of as a nitrogenous analogue of carbonic acid. That is, the C=O group in carbonic acid is replaced by a C=NH group, and each OH is replaced by a group. Isobutene can be seen as the carbon analogue in much the same way. A detailed crystallographic analysis of guanidine was elucidated 148 years after its first synthesis, despite the simplicity of the molecule. In 2013, the positions of the hydrogen atoms and their displacement parameters were accurately determined using single-crystal neutron diffraction. Production Guanidine can be obtained from natural sources, being first isolat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyurethane
Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane is produced from a wide range of starting materials. This chemical variety produces polyurethanes with different chemical structures leading to many List of polyurethane applications, different applications. These include rigid and flexible foams, varnishes and coatings, adhesives, Potting (electronics), electrical potting compounds, and fibers such as spandex and Polyurethane laminate, PUL. Foams are the largest application accounting for 67% of all polyurethane produced in 2016. A polyurethane is typically produced by reacting an isocyanate with a polyol. Since a polyurethane contains two types of monomers, which polymerize one after the other, they are classed as Copolymer#Alternating copolymers, alternating copolymers. Both the isocy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,8-Diazabicycloundec-7-ene
1,8-Diazabicyclo .4.0ndec-7-ene, or more commonly DBU, is a chemical compound and belongs to the class of amidine compounds. It is used in organic synthesis as a catalyst, a complexing ligand, and a non-nucleophilic base. Occurrence Although all commercially available DBU is produced synthetically, it may also be isolated from the sea sponge '' Niphates digitalis''. The biosynthesis of DBU has been proposed to begin with 1,6-hexanedial and 1,3-diaminopropane. Uses As a reagent in organic chemistry, DBU is used as a catalyst, a complexing ligand, and a non-nucleophilic base. It is also used as a curing agent for epoxy resins. It is used in the separation of fullerenes in conjunction with trimethylbenzene. It reacts with C70 and higher fullerenes, but not with to C60 It is also used as a catalyst in the production of polyurethanes. It also exhibited its dual character (base and nucleophile) in the synthesis of aryl- and styryl-terminal acetylenes. See also * 1,5-Diazabic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins. For upgrading of petroleum, alkylation produces a premium blending stock for gasoline. In medicine, alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells. Alkylation is accomplished with the class of drugs called alkylating antineoplastic agents. Nucleophilic alkylating agents Nucleophilic alkylating agents deliver the equivalent of an alkyl anion ( carbanion). The formal "alkyl anion" attacks an electrophile, forming a new covalent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-nucleophilic Base
As the name suggests, a non-nucleophilic base is a sterically hindered organic base that is a poor nucleophile. Normal bases are also nucleophiles, but often chemists seek the proton-removing ability of a base without any other functions. Typical non-nucleophilic bases are bulky, such that protons can attach to the basic center but alkylation and complexation is inhibited. Non-nucleophilic bases A variety of amines and nitrogen heterocycles are useful bases of moderate strength (pKa of conjugate acid * ''N'',''N''-Diisopropylethylamine (DIPEA, also called Hünig's Base), p *1,8-Diazabicycloundec-7-ene (DBU) - useful for E2 elimination reactions, pKa = 13.5 * 1,5-Diazabicyclo(4.3.0)non-5-ene (DBN) - comparable to DBU * 2,6-Di-tert-butylpyridine, a weak non-nucleophilic base pKa = 3.58 * Phosphazene bases, such as t-Bu-P4''Activation in anionic polymerization: Why phosphazene bases are very exciting promoters'' S. Boileau, N. Illy Prog. Polym. Sci., 2011, 36, 1132-1151, {{doi, 10. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylation
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 terms are commonly used in chemistry, biochemistry, soil science, and the biological sciences. In biological systems, methylation is catalyzed by enzymes; such methylation can be involved in modification of heavy metals, regulation of gene expression, regulation of protein function, and RNA processing. In vitro methylation of tissue samples is also one method for reducing certain histological staining artifacts. The reverse of methylation is demethylation. 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. Methanogenesis Methanogenesis, the process th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
