Chlorosulfonyl isocyanate

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Chlorosulfonyl isocyanate
Chlorosulfonyl isocyanate

Chlorosulfonyl isocyanate

General
Systematic name Chlorosulfonyl isocyanate
Other names N-Carbonylsulfamyl chloride
Isocyanic acid, anhydride
chloropyrosulfonyl isocyanate
Molecular formula CNClO3S
SMILES  ?
Molar mass 141.53 g/mol
Appearance colorless liquid
CAS number [1189-71-5]
Properties
Density and phase 1.626 g/cm3
Solubility in water decomp.
Other solvents Chlorocarbons
MeCN
Melting point -44 °C
Boiling point 107 °C
Structure
Molecular shape tetrahedral at S
Dipole moment  ? D
Hazards
MSDS External MSDS
Main hazards toxic, corrosive
hydrolyzes violently
NFPA 704
R/S statement R: 14-22-34-42
S: 23-26-30-36/37/39-45
RTECS number  ?
Supplementary data page
Structure and
properties
n, 1.447
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
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.

Contents

[edit] 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]

[edit] 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

[edit] Safety considerations

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

[edit] 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

[edit] External links

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