Chlorosulfonyl isocyanate 4944916 171535045 2007-11-14T22:39:08Z 151.16.57.249 {{Chembox new | Name = Chlorosulfonyl isocyanate | ImageFile = Chlorosulfonyl-isocyanate-2D.png <!-- | ImageSize = 200px --> | ImageName = Chlorosulfonyl isocyanate | ImageFile1 = Chlorosulfonyl-isocyanate-3D-vdW.png <!-- | ImageSize1 = 200px --> | ImageName1 = Chlorosulfonyl isocyanate | IUPACName = Chlorosulfonyl isocyanate | OtherNames = N-Carbonylsulfamyl chloride<br />Isocyanic acid, anhydride<br />chloropyrosulfonyl isocyanate | Section1 = {{Chembox Identifiers | SMILES = ClS(=O)(=O)\N=C=O | CASNo = 1189-71-5 }} | Section2 = {{Chembox Properties | Formula = CNClO<sub>3</sub>S | MolarMass = 141.53 g/mol | Appearance = colorless liquid | Density = 1.626 g/cm<sup>3</sup> | Solubility = decomp. | Solvent = other solvents | SolubleOther = Chlorocarbons</br>[[Acetonitrile|MeCN]] | MeltingPt = -44 °C | BoilingPt = 107 °C | RefractIndex = 1.447 }} | Section3 = {{Chembox Structure | MolShape = tetrahedral at S | Dipole = }} | Section7 = {{Chembox Hazards | ExternalMSDS = | MainHazards = toxic, corrosive<br />hydrolyzes violently }} | Section8 = {{Chembox Related | Function = compounds | OtherFunctn = SOCl<sub>2</sub></br> [[cyanogen bromide|BrCN]], POCl<sub>3</sub> }} }} '''Chlorosulfonyl isocyanate''' is the chemical compound ClSO<sub>2</sub>NCO, known as CSI. This compound is a versatile reagent in [[organic synthesis]]. ==Preparation, structure, handling== CSI is prepared by treating [[cyanogen chloride]] with [[sulfur trioxide]], the product being distilled directly from the reaction mixture.<ref>Graf, R. "Chlorosulfonyl Isocyanate" [[Organic Syntheses]], Collected Volume 5, pages 226ff.</ref> ::SO<sub>3</sub> + ClCN → ClSO<sub>2</sub>NCO In this transformation, both the carbon and the nitrogen termini of CN are functionalized. The structure of CSI is represented as ClS(O)<sub>2</sub>-N=C=O. It consists of two electron-withdrawing components, the chlorosulfonyl group (SO<sub>2</sub>Cl) and the [[isocyanate]] group (-N=C=O). Because of its resulting electrophilicity, the use of CSI in chemical synthesis requires relatively inert solvents such as chlorocarbons, acetonitrile, and ethers.<ref>Miller, M. J.; Ghosh, M.; Guzzo, P. R.; Vogt, P. F.; Hu, J.; Filzen, G. F.; Geyer, A. G. "Chlorosulfonyl Isocyanate" in "Encyclopedia of Reagents for Organic Synthesis" 2005 John Wiley & Sons: New York.</ref> ==Uses== The molecule has two electrophilic sites, the carbon and the S(VI) center.<ref>D. N. Dhar, K. S. K. Murthy "Recent Advances in the Chemistry of Chlorosulfonyl Isocyanate" Synthesis 1986; pages 437-449.</ref> CSI has been employed for the preparation of β-[[lactam]]s, some of which are medicinally important. Thus, alkenes undergo a<nowiki>[2+2]</nowiki>-cycloaddition to give the sulfonamide. The SO<sub>2</sub>Cl group can be removed simply by hydrolysis, leaving the secondary amide.<ref>Cremlyn, R. J. “An Introduction to Organosulfur Chemistry” John Wiley and Sons: Chichester (1996). ISBN 0-471-95512-4</ref> Other reactions of CSI: *Cycloaddition to alkynes to give 1,2,3-oxathiazine-2,2-dioxide-6-chlorides. *Conversion of primary alcohols to [[urethane]]s.<ref>Burgess, E. M.; Penton, Jr., H. R.; Taylor, E. A.; Williams, W. M. "Conversion of Primary Alcohols to Urethanes via the Inner Salt of Triethylammonium Hydroxide: Methyl (Carboxylsulfamoyl) Triethylammonium Hydroxide Methyl n-Hexylcarbamate" Organic Syntheses, Coll. Vol. 6, p.788</ref> *Conversion of [[carboxylic acid]]s and the acid chlorides into [[nitrile]]s. *Preparation of N,N-disubstituted [[sulfamide]]s, R<sub>2</sub>NSO<sub>2</sub>NH<sub>2</sub> ==Safety considerations== CSI is toxic, corrosive and reacts violently with water. It cannot be stored in glass-stoppered flasks, requiring instead polyethylene bottles. ==References== <references/> [[Category:Inorganic carbon compounds]] [[Category:Oxides]] [[Category:Chlorides]] [[Category:Reagents for organic chemistry]] [[ca:Template:Chembox]] [[es:Plantilla:Chembox]] [[fr:Modèle:Chimiebox général]]