Chlorosulfonyl isocyanate
Encyclopedia
Chlorosulfonyl isocyanate is the chemical compound ClSO2NCO, known as CSI. This compound is a versatile reagent in organic synthesis
.
with sulfur trioxide
, the product being distilled directly from the reaction mixture.
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.
CSI has been employed for the preparation of β-lactam
s, 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:
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
.
Preparation, structure, handling
CSI is prepared by treating cyanogen chlorideCyanogen chloride
Cyanogen chloride is an inorganic compound with the formula NCCl. This linear, triatomic pseudohalogen is an easily condensed colorless gas. More commonly encountered in the laboratory is the related compound cyanogen bromide, a room-temperature solid that is widely used in biochemical analysis and...
with sulfur trioxide
Sulfur trioxide
Sulfur trioxide is the chemical compound with the formula SO3. In the gaseous form, this species is a significant pollutant, being the primary agent in acid rain. It is prepared on massive scales as a precursor to sulfuric acid.-Structure and bonding:Gaseous SO3 is a trigonal planar molecule of...
, 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
Isocyanate
Isocyanate is the functional group of elements –N=C=O , not to be confused with the cyanate functional group which is arranged as –O–C≡N or with isocyanide, R-N≡C. Any organic compound which contains an isocyanate group may also be referred to in brief as an isocyanate. An isocyanate may have more...
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-lactam
Lactam
A lactam is a cyclic amide. Prefixes indicate how many carbon atoms are present in the ring: β-lactam , γ-lactam , δ-lactam...
s, some of which are medicinally important. Thus, alkenes undergo a
Other reactions of CSI:
- Cycloaddition to alkynes to give 1,2,3-oxathiazine-2,2-dioxide-6-chlorides.
- Conversion of primary alcohols to carbamateCarbamateCarbamates are organic compounds derived from carbamic acid . A carbamate group, carbamate ester, and carbamic acids are functional groups that are inter-related structurally and often are interconverted chemically. Carbamate esters are also called urethanes.-Synthesis:Carbamic acids are derived...
s. - Conversion of carboxylic acidCarboxylic acidCarboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
s and the acid chlorides into nitrileNitrileA nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...
s. - Preparation of N,N-disubstituted sulfamideSulfamideSulfamide is a chemical compound with the molecular structure H2NSO2NH2. Sulfamide is produced by the reaction of sulfuryl chloride with ammonia.-Sulfamide functional group.:...
s, R2NSO2NH2