Camphorsulfonic acid

Camphorsulfonic acid

Wireframe model of camphorsulfonic acid
Names
Preferred IUPAC name (7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonic acid
Other names Reychler's acid; 2-Oxobornane-10-sulfonic acid
Identifiers
CAS Number	5872-08-2^Y 35963-20-3 (1R)^Y 3144-16-9 (1S)^Y
3D model (JSmol)	Interactive image Interactive image
Beilstein Reference	2216194
ChEBI	CHEBI:55379^Y
ChemSpider	17438^Y 116050 (1R)^Y 189449 (1S)^Y 2318313 (4S)^Y
ECHA InfoCard	100.025.024
EC Number	227-527-0
MeSH	10-Camphorsulfonic+acid
PubChem CID	18462 131278 (1R) 218580 (1S) 43833349 (4R) 3057042 (4S)
UNII	D8D049375Q^Y Y6075I4FXE (1R)^Y 9TLZ01S15L (1S)^Y
UN number	1759
CompTox Dashboard (EPA)	DTXSID60863113
InChI InChI=1S/C10H16O4S/c1-9(2)7-3-4-10(9,8(11)5-7)6-15(12,13)14/h7H,3-6H2,1-2H3,(H,12,13,14)^Y Key: MIOPJNTWMNEORI-UHFFFAOYSA-N^Y
SMILES CC1(C2CCC1(C(=O)C2)CS(=O)(=O)O)C O=S(=O)(O)CC12C(=O)CC(CC1)C2(C)C
Properties
Chemical formula	C10H16O4S
Molar mass	232.29 g·mol^−1
Melting point	195 °C (decomposes)
Acidity (pKa)	1.2
Hazards
Safety data sheet (SDS)	External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references

Camphorsulfonic acid, sometimes abbreviated CSA or 10-CSA is an organosulfur compound. Like typical sulfonic acids, it is a relatively strong acid that is a colorless solid at room temperature and is soluble in water and a wide variety of organic substances.

This compound is commercially available. It can be prepared by sulfonation of camphor with sulfuric acid and acetic anhydride:[1]

Although this reaction appears to be a sulfonation of an unactivated methyl group, the actual mechanism is believed to involve a retro-semipinacol rearrangement, deprotonation next to the tertiary carbocation to form an alkene, sulfonation of the alkene intermediate, and finally, semipinacol rearrangement to re-establish the ketone function.[2]

In organic synthesis, CSA and its derivatives can be used as resolving agents for chiral amines and other cations.[3][4] The synthesis of osanetant was an example of this. 3-bromocamphor-8-sulfonic acid was used in the synthesis of enantiopure devazepide.[5]

Camphorsulfonic acid is also being used for the synthesis of quinolines.[6] Camphorsulfonic acid is used in some pharmaceutical formulations, where is it referred to as camsilate or camsylate, including trimetaphan camsilate and lanabecestat camsylate. Some studies (c.f. Lednicer) support that D-CSA was used for the resolution of Chloramphenicol.

References

1. Bartlett, Paul D.; Knox, L. H. (1965). "D,L-10-Camphorsulfonic acid (Reychler's Acid)". Organic Syntheses. 45: 12. doi:10.15227/orgsyn.045.0012.
2. Brückner, Reinhard (2002). Advanced organic chemistry : reaction mechanisms. San Diego: Harcourt/Academic Press. ISBN 9780080498805. OCLC 269472848.
3. Clark, Robin D.; Kern, John R.; Kurz, Lilia J.; Nelson, Janis T. (1990). "Preparation of Enatiomerically Pure Decahydro-6H-isoquino[2,1-g][1,6]naphthyridines Utilizing the Openshaw-Whittaker Hexahydrobenzo[a]quinolizinone Resolution". Heterocycles. 31 (2): 353. doi:10.3987/COM-89-5250.
4. Charette, André B. (2001). "3-Bromocamphor-8-sulfonic Acid". Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons. doi:10.1002/047084289X.rb283. ISBN 0471936235.
5. Reider, Paul J.; Davis, Paul; Hughes, David L.; Grabowski, Edward J. J. (1987). "Crystallization-induced asymmetric transformation: Stereospecific synthesis of a potent peripheral CCK antagonist". J. Org. Chem. 52 (5): 955–957. doi:10.1021/jo00381a052.
6. Chandra, Devesh; Dhiman, Ankit K; Kumar, Rakesh; Sharma, Upendra (2019). "Microwave-Assisted Metal-Free Rapid Synthesis of C4-Arylated Quinolines via Povarov Type Multicomponent Reactiont". Eur. J. Org. Chem. 2019 (16): 2753–2758. doi:10.1002/ejoc.201900325. S2CID 107383202.