| 词条 | N,N,N′,N′-Tetramethylformamidinium chloride |
| 释义 |
| Name =N,N,N′,N′-Tetramethylformamidinium chloride | ImageFile = File:Tetramethylformamidiniumchlorid Struktur.svg | ImageSize = 200px | ImageAlt = | IUPACName = | OtherNames =(Dimethylaminomethylene)dimethylammonium chloride | Section1 = {{Chembox Identifiers | CASNo = 1071-38-1 | PubChem = 9793790 | ChemSpiderID = 7969557 | SMILES = [Cl-].[N+](=C\(C)C)(\\C)C | StdInChI = 1S/C5H13N2.ClH/c1-6(2)5-7(3)4;/h5H,1-4H3;1H/q+1;/p-1 | StdInChIKey = BPBLGCSAYMJJJW-UHFFFAOYSA-M }} | Section2 = {{Chembox Properties | C=5|H=13|Cl=1|N=2 | Appearance = Solid | Density = | MeltingPt = | BoilingPt = | Solubility = }} | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}N,N,N′,N′-Tetramethylformamidinium chloride is the simplest representative of quaternary formamidinium cations of the general formula [R2N−CH=NR2]+ with a chloride as a counterion in which all hydrogen atoms of the protonated formamidine [HC(=NH2)NH2]+ are replaced by methyl groups.[1] Deprotonation results in the exceptionally basic bis(dimethylamino)carbene R2N−C̈−NR2.[2] PreparationN,N,N′,N′-Tetramethylformamidinium chloride is obtained in very high yield (95%) in the reaction of dimethylformamide (DMF) with dimethylcarbamoyl chloride:[3]The conversion of DMF with thionyl chloride in a ratio of 3:1 obtains the product in a is significantly lower yield (72%) which appears, however, more realistic in view of the tricky handling of the chloride salt.[4] PropertiesN,N,N′,N′-Tetramethylformamidinium chloride is a light yellow, strongly hygroscopic solid.[5]For drying, the salt is dissolved in dichloromethane and the solution is treated with solid anhydrous sodium sulfate. After several dissolutions in dichloromethane and acetone, and precipitations with tetrahydrofuran, a colorless solid is obtained, which is stable under air and moisture sealing.[1] The presumption of a mesomeric equilibrium between ionic formamidinium chloride and covalent bis(dimethylamino)chloromethane structure: could be decided by reaction with germanium(II) chloride or tin(II) chloride in favour of the presence of N,N,N′,N′-tetramethylformamidinium chloride.[6] The extreme hygroscopy of the chloride salt considerably complicates the handling of the compound. Therefore, also syntheses of the much better processible salts N,N,N′,N′-tetramethylformamidinium methylsulfate[5] (from the dimethylformamide–dimethylsulfate complex[7]) and of N,N,N′,N′-tetramethylformamidinium p-toluenesulfonate (from dimethylformamide and p-toluenesulfonyl chloride) were investigated.[8][9] ApplicationsN,N,N′,N′-Tetramethylformamidinium chloride is useful as a reagent for aminomethylenation (that is, to introduce a =CH−NR1R2 function to CH-acidic compounds). For example, ethyl cyanoacetate reacts with the formamidinium salt in the presence of solid sodium hydroxide to give ethyl (dimethylaminomethylene)cyanoacetate in practically quantitative yields.[10]The aminomethylenation provides intermediates for the synthesis of heterocycles such as indoles, pyrimidines, pyridines and quinolones. N,N,N′,N′-Tetramethylformamidinium chloride reacts with alkali metal dimethylamides (such as lithium dimethylamide or sodium dimethylamide) to tris(dimethylamino)methane in yields of 55% to 84%.[11][12][13]The reaction product is suited as a reagent for formylation and aminomethylenation. From N,N,N′,N′-tetramethylformamidinium chloride and sodium ethoxide in ethanol, dimethylformamide diethyl acetal is formed in 68% yield.[14] In aqueous sodium cyanide, N,N,N′,N′-tetramethylformamidinium reacts to bis(dimethylamino)acetonitrile.[15] From N,N,N′,N′-tetramethylformamidinium and anhydrous hydrogen cyanide, dimethylaminomalonic acid dinitrile is obtained in 92% yield.[18] N,N,N′,N′-Tetramethylformamidinium can be regaminated with cyclo-aliphatic amines to the corresponding heterocyclic formamidines.[16]More recently, the use of N,N,N′,N′-tetramethylformamidinium as a catalyst in the preparation of acyl chlorides from carboxylic acids and phosgene has been reported.[17] Strong bases (such as phenyllithium) can abstract a proton from the formamidinium cation of N,N,N′,N′-tetramethylformamidinium forming bis(dimethylamino)carbene.[1][2]References1. ^1 2 {{cite journal|first1=R. W. |last1=Alder |first2=M. E. |last2=Blake |first3=S. |last3=Bufali |first4=C. P. |last4=Butts |first5=A. G. |last5=Orpen |first6=J. |last6=Schütz |first7=S. J. |last7=Williams |journal=Journal of the Chemical Society, Perkin Transactions |title=Preparation of tetraalkylformamidinium salts and related species as precursors to stable carbenes |issue=1 |volume=2001 |page=1586–1593 |date=2001 |DOI=10.1039/B104110J}} {{DEFAULTSORT:Tetramethylformamidinium chloride, N,N,N',N'-}}2. ^1 {{cite journal|first1=A. M. |last1=Magill |first2=K. J. |last2=Cavell |first3=B. F. |last3=Yates |journal=Journal of the American Chemical Society |title=Basicity of nucleophilic carbenes in aqueous and nonaqueous solvents – theoretical predictions |volume=126 |issue=28 |page=8717–8724 |date=2004 |DOI=10.1021/ja038973x}} 3. ^{{cite journal|first=Z. |last=Arnold |journal=Collection of Czechoslovak Chemical Communications |title=The preparation of tetramethylformamidinium salts and their vinylogues |volume=24 |page=760–765 |date=1959 |DOI=10.1135/cccc19590760}} 4. ^{{cite journal|first1=W. |last1=Kantlehner |first2=P. |last2=Speh |journal=Chemische Berichte |title=Säureamid-Reaktionen. LI. Notiz zur Darstellung von N,N,N′,N′-Tetramethylformamidiniumchlorid |trans-title=Acyl amide reactions. LI. Note on the presentation of N,N,N′,N′-tetramethylformamidinium chloride |volume=104 |issue=11 |page=3714–3715 |date=1971 |language=German |DOI=10.1002/cber.19711041136}} 5. ^1 {{Cite patent|country = DE|number =1205528 |Code= |title=Verfahren zur Herstellung von N-substituierten Amidinen oder deren Vinylogen |trans-title=Process for the preparation of N-substituted amidines or their vinylogues |gdate=1965-11-25 |fdate=1962-02-08 |invent1=Bredereck, H. |invent2=Effenberger, F. |invent3=Simchen, G. |assign1=Bredereck, H.}} 6. ^{{cite journal|first1=X. |last1=Tian |first2=T. |last2=Pape |first3=N. W. |last3=Mitzel |journal=Zeitschrift für Naturforschung |title=Formamidinium Salts of Low Valent Metal Halide Anions {{chem|MX|3|-}} (M = Ge, Sn) and {{chem|M|2|X|6|2-}} (M = Ga, In) |volume=59b |issue=11–12 |page=1524–1531 |date=2004 |DOI=10.1515/znb-2004-11-1224}} 7. ^{{cite journal|first1=H. |last1=Bredereck |first2=F. |last2=Effenberger |first3=G. |last3=Simchen |periodical=Chemische Berichte |title=Säureamid-Reaktionen. XXXII. Über Säureamid-Dialkylsulfat-Komplexe |trans-title=Acyl amide reactions. XXXII. On acyl amide–dialkylsulfate complexes |volume=96 |issue=5 |page=1350–1355 |date=1963 |language=German |DOI=10.1002/cber.19630960526}} 8. ^{{Cite patent|country = US|number =3707553 |title=Tetramethylformamidinium arenesulfonates and method of preparation |gdate=1972-12-26 |fdate=1965-8-24 |invent1=Bagley, G. E. |invent2=Poshkus A. 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The reaction of arylsulfonyl chlorides and arylsulfonic acids with dimethylformamide |volume=100 |issue=5 |page=1590–1595 |date=1969 |language=German |DOI=10.1007/BF00900174}} 10. ^{{Cite patent|country = US|number =5241099 |title=Process for the preparation of aminomethylene compounds |gdate=1993-08-31 |fdate=1992-03-16 |invent1=Blank, H.-U. |invent2=Kraus, H. |assign1=Bayer AG}} 11. ^{{cite journal|first1=H. |last1=Bredereck |first2=F. |last2=Effenberger |first3=T. |last3=Brendle |journal=Angewandte Chemie |title=Synthese und Reaktionen von Trisdimethylaminomethan |trans-title=Synthesis and reactions of tris(dimethylamino)methane |volume=78 |issue=2 |page=147–148 |date=1966 |language=German |DOI=10.1002/ange.19660780212}} 12. ^{{Cite patent|country =DE |number =1217391 |title=Verfahren zur Herstellung von Tris-dimethylaminomethan |trans-title=Process for the preparation of tris(dimethylamino)methane) |gdate=1966-12-08 |fdate=1964-09-29 |invent1=Bredereck, H. |invent2-first=Effenberger, F. |invent3-first=T. |invent3-last=Brendle |assign1=Bredereck, H.}} 13. ^{{cite journal|first1=H. |last1=Bredereck |first2=F. |last2=Effenberger |first3=T. |last3=Brendle |first4=H. |last4=Muffler |journal=Chemische Berichte |title=Orthoamide. 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Synthesis of O,N- and N,N-acetals of α-keto-carboxylic acid nitriles as well as imino esters |volume=104 |issue=3 |page=924–931 |date=1971 |language=German |DOI=10.1002/cber.19711040331}} 16. ^1 {{cite journal|first1=H. |last1=Gold |first2=O. |last2=Bayer |journal=Chemische Berichte |title=Die Darstellung basisch substituierter Malonsäure-dinitrile |trans-title=Presentation of base-substituted malonic acid dinitriles |volume=94 |issue=10 |page=2594–2596 |date=1961 |language=German |DOI=10.1002/cber.19610941004}} 17. ^{{Cite patent|country =EP |number =1124783 |Code=A1 |title=Method for producing carboxylic acid chlorides |gdate=2001-08-22 |fdate=1998-11-04 |invent1=Henkelmann, J. |invent2=Stamm, A. |assign1=BASF AG}} 1 : Amidines |
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