WordNet
- performed comprehensively and completely; "an exhaustive study"; "made a thorough search"; "thoroughgoing research" (同)thorough, thoroughgoing
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- 余すところのない,徹底的な
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出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/10/28 19:24:05」(JST)
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Hofmann elimination, also known as exhaustive methylation, is a process where an tertiary amine is reacted to create a quat. amine salt and an alkene by treatment with excess methyl iodide followed by treatment with silver oxide, water, and heat.
After the first step, a quaternary ammonium iodide salt is created. After replacement of iodine by an hydroxyl anion, an elimination reaction takes place to the alkene.
With asymmetrical amines, the major alkene product is the least substituted and generally the least stable, an observation known as the Hofmann rule. This is in direct contrast to normal elimination reactions where the more substituted, stable product is dominant (Zaitsev's rule).
The reaction is named after its discoverer, August Wilhelm von Hofmann.[1]
An example is the synthesis of trans-cyclooctene:[2]
In a related chemical test called Herzig–Meyer alkimide group determination a tertiary amine with at least one methyl group and lacking a beta-proton is allowed to react with hydrogen iodide to the quaternary ammonium salt which when heated degrades to iodomethane and the secondary amine.[3]
See also
- Hofmann rearrangement
- Emde degradation
References
- ^ Aug. Wilh. von Hofmann (1851). "Beiträge zur Kenntniss der flüchtigen organischen Basen". Annalen der Chemie und Pharmacie 78 (3): 253–286. doi:10.1002/jlac.18510780302.
- ^ Arthur C. Cope; Robert D. Bach (1973). "trans-Cyclooctene". Org. Synth. ; Coll. Vol. 5, p. 315
- ^ J. Herzig; H. Meyer (1894). "Ueber den Nachweis und die Bestimmung des am Stickstoff gebundenen Alkyls". Berichte der deutschen chemischen Gesellschaft 27 (1): 319–320. doi:10.1002/cber.18940270163.
External links
- An animation of the mechanism of the Hofmann elimination
UpToDate Contents
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English Journal
- Exhaustive methylation analysis revealed uneven profiles of methylation at IGF2/ICR1/H19 11p15 loci in Russell Silver syndrome.
- Azzi S1, Steunou V2, Tost J3, Rossignol S4, Thibaud N5, Das Neves C5, Le Jule M5, Habib WA4, Blaise A6, Koudou Y7, Busato F8, Le Bouc Y4, Netchine I4.
- Journal of medical genetics.J Med Genet.2015 Jan;52(1):53-60. doi: 10.1136/jmedgenet-2014-102732. Epub 2014 Nov 13.
- BACKGROUND: The structural organisation of the human IGF2/ICR1/H19 11p15 domain is very complex, and the mechanisms underlying its regulation are poorly understood. The Imprinted Center Region 1 (ICR1) contains seven binding sites for the zinc-finger protein CTCF (CBS: CTCF Binding Sites); three add
- PMID 25395389
- MeCP2: the long trip from a chromatin protein to neurological disorders.
- Ausió J1, de Paz AM2, Esteller M3.
- Trends in molecular medicine.Trends Mol Med.2014 Sep;20(9):487-98. doi: 10.1016/j.molmed.2014.03.004. Epub 2014 Apr 21.
- Since the discovery of its fundamental involvement in Rett syndrome, methyl CpG binding protein 2 (MeCP2) has been the focus of an exhaustive biochemical and functional characterization. It is now becoming apparent that the intrinsic highly disordered nature of MeCP2, which is amenable to a plethora
- PMID 24766768
- Non-exhaustive DNA methylation-mediated transposon silencing in the black truffle genome, a complex fungal genome with massive repeat element content.
- Montanini B, Chen PY, Morselli M, Jaroszewicz A, Lopez D, Martin F, Ottonello S, Pellegrini M.
- Genome biology.Genome Biol.2014 Jul 31;15(7):411. doi: 10.1186/s13059-014-0411-5.
- BACKGROUND: We investigated how an extremely transposon element (TE)-rich organism such as the plant-symbiotic ascomycete truffle Tuber melanosporum exploits DNA methylation to cope with the more than 45,000 repeated elements that populate its genome.RESULTS: Whole-genome bisulfite sequencing perfor
- PMID 25091826
Japanese Journal
- 70(P49) 中国産桑白皮より得られるフェノール性成分sanggenon類の構造訂正について(ポスター発表の部)
- 野村 太郎,羽野 芳生,深井 俊夫,神崎 隆一
- 天然有機化合物討論会講演要旨集 (38), 415-420, 1996-09-02
- … Sanggenon A trimethyl ether (2e) having a diketone structure derived by exhaustive methylation with dimethyl sulfate gave a phenazine derivative by treatment with o-phenylenediamine under acidic condition. …
- NAID 110006679798
- Studies on the carbohydrate-protein linkage region in bovine corneal keratan sulfate. II. Structural studies on linkage region-enriched neutral glycopeptides.:II. Structural Studies on Linkage Region-Enriched Neutral Glycopeptides
- YAMAGUCHI Haruki
- The Journal of Biochemistry 94(1), 215-221, 1983
- … In order to elucidate the chemical structure of the carbohydrate-protein linkage region of bovine corneal keratan sulfate, glycopeptides which had been highly enriched in the linkage region under mild conditions were subjected to glycosidase digestion in combination with methylation analysis. …
- NAID 130003542540
- Structure of the alkali-insoluble skeletal glucan of Lentinus edodes.
- SHIDA Mariko,USHIODA Yoko,NAKAJIMA Tasuku,MATSUDA Kazuo
- The Journal of Biochemistry 90(4), 1093-1100, 1981
- … An alkali-insoluble core material was isolated from the fruit bodies of Lentinus edodes after exhaustive extraction with 24%. … Methylation analysis has shown that the glucan part of the core material (skeletal glucan) has a highly branched structure with 1, 6 and 1, 3 linkages in a molar ratio of 2:1. …
- NAID 130003541942
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- exhaustive methylation
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