Chlorosulfonyl isocyanate
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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
- ^ Graf, R. "Chlorosulfonyl Isocyanate" Organic Syntheses, Collected Volume 5, pages 226ff.
- ^ 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.
- ^ D. N. Dhar, K. S. K. Murthy "Recent Advances in the Chemistry of Chlorosulfonyl Isocyanate" Synthesis 1986; pages 437-449.
- ^ Cremlyn, R. J. “An Introduction to Organosulfur Chemistry” John Wiley and Sons: Chichester (1996). ISBN 0-471-95512-4
- ^ 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