[127-65-1]  · C7H13ClNNaO5S  · Chloramine-T  · (MW 281.69)

(source of chloronium cations and/or nitrogen anions; oxidizing agent; in conjunction with OsO4 can hydroxyaminate alkenes)

Alternate Names: N-chloro-N-sodio-p-toluenesulfonamide.

Physical Data: mp 167-170 °C (dec).

Solubility: insol ether, benzene and chloroform; sol cold H2O; v sol hot H2O; dec in EtOH.

Form Supplied in: white or pale yellow solid; widely available. While other N-halo-N-sodiosulfonamides and -carbamates have been reported in the literature and used in organic synthesis, only chloramine-T and its demethyl analog, chloramine-B, are commercially available. Drying: in some reactions, anhydrous chloramine-T [chloramine-T (anhyd)] is required; the drying of the trihydrate at 80 °C under vacuum has been described,2 although precautions should be taken (see below).

Analysis of Reagent Purity: by iodometric titration.3

Handling, Storage, and Precautions: irritant; keep containers tightly sealed and protect from light; although the trihydrate is stable, there have been reports of chloramine-T (anhyd) decomposing with explosive force;2,4 to minimize potential risks it is advised that chloramine-T (anhyd) be prepared in minimal amounts and all manipulations be performed behind safety shields (full-face and free-standing); use in a fume hood.

Reaction with Chalcogens and their Derivatives.

Chloramine-T reacts with a variety of sulfur-containing compounds to form sulfur-nitrogen bonds.1 A partial listing includes thiols, sulfides, sulfoxides, disulfides, sulfimides, xanthates, thioketones, sulfenyl chlorides, and sulfinyl chlorides. The reaction of chloramine-T with sulfides forms the basis for a deprotection of thioacetal groups. Thus 1,3-oxathiolanes,5 1,3-dithiolanes,6 and 1,3-dithianes7 are all cleaved by chloramine-T to regenerate the carbonyl compounds. However, with chloramine-T (anhyd), 1,3-dithianes yield ketene thioacetals (eq 1).8

Selenides react with chloramine-T (anhyd) to give selenimides (eq 2).9 In the case of primary alkyl phenyl selenides, the selenimide further undergoes b-elimination to give the terminal alkene (eq 3).10 Tellurides behave similarly.11 Allyl phenyl selenides can be converted to protected allylic amines via [2,3]-sigmatropic rearrangement of the selenimides (eq 4).12

Diphenyl disulfide and diphenyl diselenide react with chloramine-T (anhyd) to give reagents that convert alkenes to trans-vicinal phenylthio(seleno)-N-tosylamines (eq 5).13 Extension of this to the synthesis of a-phenylthio(seleno) ketones from silyl enol ethers has been reported.14

Chloramine-T (anhyd) converts selenium and tellurium metal to the diimide species (1) and (2), respectively. The selenium analog (1) has been used for the allylic amination of alkenes and alkynes (eq 6),2,15 while its tellurium counterpart (2) has found utility in the synthesis of N-tosylimines from aldehydes.16 Compound (1) has also been used in the 1,2-diamination of 1,3-dienes, but the yields were poor.17

Other Reactions with Alkenes.

Chloramine-T, either alone or in conjunction with other agents, reacts with a variety of carbon-carbon double bonds to generate useful products. Under acidic conditions in aqueous acetone, alkenes give chlorohydrins,18 while in an acetic acid medium the acetylated products are produced.19 An intramolecular version allows for the synthesis of chlorolactones (eq 7).20 Electron-rich alkenes, such as enamines, react to give a-aminated aldehydes (eq 8).21 Vinyl ethers give the a-(N-tosylamino)aldehydes.

The reaction of alkenes with chloramine-T in the presence of catalytic amounts of Osmium Tetroxide provides a convenient and general method for the vicinal oxyamination of alkenes (eq 9).22 Phase transfer conditions have also been employed.23

Other Oxidations.

Chloramine-T reacts with NaBr and NaI to provide a convenient method of generating BrCl and ICl, respectively, in situ (see Bromine Chloride).24,25 Chloramine-T has also been used to oxidize aldoximes to nitrile oxides as part of a synthesis of isoxazolines (eq 10).26 A similar oxidation of aldehyde hydrazones to nitrilimines has also been reported.27

1. (a) Campbell, M. M.; Johnson, G. CRV 1978, 78, 65. (b) Bremner, D. H. In Synthetic Reagents; Pizey, J. S., Ed.; Wiley: New York, 1985; Vol. 6, pp 9-59.
2. Sharpless, K. B.; Hori, T.; Truesdale, L. K.; Dietrich, C. O. JACS 1976, 98, 269.
3. Reagent Chemicals: American Chemical Society Specifications, 8th ed.; American Chemical Society: Washington, 1993; pp 242-244.
4. Klundt, I. L. Chem. Eng. News 1977, 55 (49), 56.
5. Emerson, D. W.; Wynberg, H. TL 1971, 3445.
6. Huurdeman, W. F. J.; Wynberg, H.; Emerson, D. W. TL 1971, 3449.
7. Huurdeman, W.; Wynberg, H.; Emerson, D. W. SC 1972, 2, 7.
8. Yoshida, H.; Ogata, T.; Inokawa, S. S 1976, 552.
9. Hellwinckel, D.; Fahrbach, G. LA 1968, 715, 68.
10. Sharpless, K. B.; Gordon, K. M.; Lauer, R. F.; Patrick, D. W.; Singer, S. P.; Young, M. W. CS 1975, 8A, 9 (CA 1976, 85, 4632k).
11. Otsubo, T.; Ogura, F.; Yamaguchi, H.; Higuchi, H.; Sakata, Y.; Misumi, S. CL 1981, 447.
12. (a) Fankhauser, J. E.; Peevey, R. M.; Hopkins, P. B. TL 1984, 25, 15. (b) For the use of N-chloro-N-sodiocarbamates to furnish the synthetically more useful Boc- or Cbz-protected primary allylic amines, see: Shea, R. G.; Fitzner, J. N.; Fankhauser, J. E.; Hopkins, P. B. JOC 1984, 49, 3647.
13. Barton, D. H. R.; Britten-Kelly, M. R.; Ferreira, D. JCS(P1) 1978, 1090.
14. Magnus, P.; Rigoller, P. TL 1992, 33, 6111.
15. The corresponding sulfur analog appears to be superior to (1) as an aminating agent. However, chloramine-T is not used in its synthesis; see: Sharpless, K. B.; Hori, T. JOC 1976, 41, 176.
16. Trost, B. M.; Marrs, C. JOC 1991, 56, 6468.
17. Sharpless, K. B.; Singer, S. P. JOC 1976, 41, 2504.
18. Damin, B.; Garapon, J.; Sillion, B. S 1981, 362.
19. Damin, B.; Garapon, J.; Sillion, B. TL 1980, 1709.
20. Damin, B.; Forestiere, A.; Garapon, J.; Sillion, B. JOC 1981, 46, 3552.
21. Dyong, I.; Lam-Chi, Q. AG(E) 1979, 18, 933.
22. (a) Sharpless, K. B.; Chong, A. O.; Oshima, K. JOC 1976, 41, 177. (b) Herranz, E.; Sharpless, K. B. OSC 1990, 7, 375.
23. Herranz, E.; Sharpless, K. B. JOC 1978, 43, 2544.
24. Kabalka, G. W.; Sastry, K. A. R.; Hsu, H. C.; Hylarides, M. D. JOC 1981, 46, 3113.
25. (a) Kabalka, G. W.; Gooch, E. E. JOC 1981, 46, 2582. (b) Kometani, T.; Watt, D. S.; Ji, T. TL 1985, 26, 2043.
26. Hassner, A.; Lokanatha Rai, K. M. S 1989, 57.
27. Lokanatha Rai, K. M.; Hassner, A. SC 1989, 19, 2799.

R. Richard Goehring

Scios Nova, Baltimore, MD, USA

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