Chlorosulfonyl isocyanate

Chlorosulfonyl isocyanate

Names
IUPAC name Chlorosulfonyl isocyanate
Other names N-Carbonylsulfamyl chloride Chloropyrosulfonyl isocyanate Sulfuryl chloride isocyanate
Identifiers
CAS Number	1189-71-5 Y
3D model (JSmol)	Interactive image
ChemSpider	64080 Y
EC Number	214-715-2
PubChem CID	70918
UNII	2903Y990SM Y
InChI InChI=1S/CClNO3S/c2-7(5,6)3-1-4 Y Key: WRJWRGBVPUUDLA-UHFFFAOYSA-N Y InChI=1/CClNO3S/c2-7(5,6)3-1-4 Key: WRJWRGBVPUUDLA-UHFFFAOYAX
SMILES ClS(=O)(=O)N=C=O
Properties
Chemical formula	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)
Solubility in water	decomposition
Solubility in other solvents	Chlorocarbons MeCN
Refractive index (nD)	1.447
Structure
Molecular shape	tetrahedral at S
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	toxic, corrosive, flammable, reacts violently with water
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H312, H314, H330, H332, H334
Precautionary statements	P260, P261, P264, P270, P271, P280, P284, P285, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P312, P304+P340, P304+P341, P305+P351+P338, P310, P312, P320, P321, P322, P330, P342+P311, P363, P403+P233, P405, P501
NFPA 704 (fire diamond)	<imagemap> File:NFPA 704.svg|80px|alt=NFPA 704 four-colored diamond poly 150 150 300 300 150 450 0 300 Health 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gas poly 300 0 450 150 300 300 150 150 Flammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oil poly 450 150 600 300 450 450 300 300 Instability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorus poly 300 300 450 450 300 600 150 450 Special hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid desc none </imagemap> 3 1 2 W
Safety data sheet (SDS)	"External MSDS"
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). Y verify (what is YN ?) 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.

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.

Uses

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

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. Other reactions of CSI:

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

Safety considerations

CSI is toxic, corrosive and reacts violently with water.