My watch list
my.chemeurope.com  
Login  

Chlorosulfonyl isocyanate



Chlorosulfonyl isocyanate
IUPAC name Chlorosulfonyl isocyanate
Other names N-Carbonylsulfamyl chloride
Isocyanic acid, anhydride
chloropyrosulfonyl isocyanate
Identifiers
CAS number 1189-71-5
SMILES ClS(=O)(=O)\N=C=O
Properties
Molecular formula CNClO3S
Molar mass 141.53 g/mol
Appearance colorless liquid
Density 1.626 g/cm3
Melting point

-44 °C

Boiling point

107 °C

Solubility in water decomp.
Solubility in other solvents Chlorocarbons
MeCN
Refractive index (nD) 1.447
Structure
Molecular shape tetrahedral at S
Hazards
Main hazards toxic, corrosive
hydrolyzes violently
Related Compounds
Related compounds SOCl2
BrCN, POCl3
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Chlorosulfonyl isocyanate is the chemical compound ClSO2NCO, known as CSI. This compound is a versatile reagent in organic synthesis.

Additional recommended knowledge

Contents

Preparation, structure, handling

CSI is prepared by treating cyanogen chloride with sulfur trioxide, the product being distilled directly from the reaction mixture.[1]

SO3 + ClCN → ClSO2NCO

In this transformation, both the carbon and the nitrogen termini of CN are functionalized.

The structure of CSI is represented as ClS(O)2-N=C=O. It consists of two electron-withdrawing components, the chlorosulfonyl group (SO2Cl) 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.[2]

Uses

The molecule has two electrophilic sites, the carbon and the S(VI) center.[3]

CSI has been employed for the preparation of β-lactams, some of which are medicinally important. Thus, alkenes undergo a[2+2]-cycloaddition to give the sulfonamide. The SO2Cl group can be removed simply by hydrolysis, leaving the secondary amide.[4] Other reactions of CSI:

  • Cycloaddition to alkynes to give 1,2,3-oxathiazine-2,2-dioxide-6-chlorides.
  • Conversion of primary alcohols to urethanes.[5]
  • Conversion of carboxylic acids and the acid chlorides into nitriles.
  • Preparation of N,N-disubstituted sulfamides, R2NSO2NH2

Safety considerations

CSI is toxic, corrosive and reacts violently with water. It cannot be stored in glass-stoppered flasks, requiring instead polyethylene bottles.

References

  1. ^ Graf, R. "Chlorosulfonyl Isocyanate" Organic Syntheses, Collected Volume 5, pages 226ff.
  2. ^ 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.
  3. ^ D. N. Dhar, K. S. K. Murthy "Recent Advances in the Chemistry of Chlorosulfonyl Isocyanate" Synthesis 1986; pages 437-449.
  4. ^ Cremlyn, R. J. “An Introduction to Organosulfur Chemistry” John Wiley and Sons: Chichester (1996). ISBN 0-471-95512-4
  5. ^ 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
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Chlorosulfonyl_isocyanate". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE