Chlorosulfonyl isocyanate
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| Names | |
|---|---|
| IUPAC name
Chlorosulfonyl isocyanate | |
| Other names
N-Carbonylsulfamyl chloride Chloropyrosulfonyl isocyanate Sulfuryl chloride isocyanate | |
| Identifiers | |
1189-71-5  | |
| 3D model (Jmol) | Interactive image |
| ChemSpider | 64080 |
| ECHA InfoCard | 100.013.378 |
| PubChem | 70918 |
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| Properties | |
| CNClO3S | |
| Molar mass | 141.53 g/mol |
| Appearance | colorless liquid |
| Density | 1.626 g/cm3 |
| Melting point | −44 °C (−47 °F; 229 K) |
| Boiling point | 107 °C (225 °F; 380 K) |
| decomposition | |
| Solubility in other solvents | Chlorocarbons MeCN |
| Refractive index (nD) |
1.447 |
| Structure | |
| tetrahedral at S | |
| Hazards | |
| Main hazards | toxic, corrosive, flammable, reacts violently with water |
| Safety data sheet | "External MSDS" |
| R-phrases | R14 R20 R24/25 R29 R34 R42/43[1] |
| S-phrases | (S1/2) S8 S24 S26 S30 S36/37/39 S38 S45 [1] |
| NFPA 704 | |
| Related compounds | |
| Related compounds |
Thionyl chloride Cyanogen bromide Phosphoryl chloride |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
Chlorosulfonyl isocyanate is the chemical compound ClSO2NCO, 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.[2]
- 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.[3]
Uses
The molecule has two electrophilic sites, the carbon and the S(VI) center.[4]
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.[5] Other reactions of CSI:
- Cycloaddition to alkynes to give 1,2,3-oxathiazine-2,2-dioxide-6-chlorides.
- Conversion of primary alcohols to carbamates.[6]
- 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 2 http://fscimage.fishersci.com/msds/54436.htm
- ↑ 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