Sulfilimine

Ball-and-stick model of the diphenylsulfimide molecule, Ph₂S=NH ^[1]

A sulfilimine (sulfimide) is a type of chemical compound containing a sulfur to nitrogen double bond. The parent compound is sulfilimine H₂S=NH, which is mainly of theoretical interest. Other simple examples are methylphenylsulfoximine^[2] and S,S-diphenylsulfilimine:^[3]

Methyl-phenylsulfoximine, a sulfur(VI) compound, and S,S-diphenylsulfilimine, a sulfur(IV) compound.

Preparation

Most sulfilimines are N-substituted with electron-withdrawing groups. These compounds are typically prepared by oxidation of thioethers with electrophilic amine reagents, such as chloramine-T in the presence of a base:^[4]

R₂S + ClNHTs → R₂S=NTs + HCl

An alternative route involves reactions of electrophilic sulfur compounds with amines. The limidosulfonium reagents provide a source of "Me₂S²⁺", which are attacked by amines.

Sulfilimine bonds in proteins

Sulfilimine bonds stabilize collagen IV strands found in the extracellular matrix.^[5] These bonds covalently connect hydroxylysine and methionine residues of adjacent polypeptide strands to form a larger collagen trimer.

References

1. The preparation and structure of novel sulfimide systems; X-ray crystal structures of 1,4-(PhS{NH})2C6H4(and dihydrate), 1,2-(PhS{NH})(PhS)C6H4·H2O and of [Ph2SNH] and its hydrate Mark R. J. Elsegood, Kathryn E. Holmes, Paul F. Kelly, Jonathan Parr and Julia M. Stonehouse New J. Chem., 2002, 26, 202 - 206. doi:10.1039/b103502a
2. sigmaaldrich.com/catalog methyl-phenylsulfoximine
3. sigmaaldrich.com/catalog S,S-diphenylsulfilimine
4. Gilchrist, T. L.; Moody, C. J., "The chemistry of sulfilimines", Chem. Rev. 1977, 77, 409-435. doi:10.1021/cr60307a005
5. Vanacore R, Ham AL, Voehler M, Sanders CR, Conrads TP, Veenstra TD, Sharpless KB, Dawson PE, Hudson BG (September 4, 2009). "A sulfilimine bond identified in collagen IV.". Science 325 (5945): 1230–1234. Bibcode:2009Sci...325.1230V. doi:10.1126/science.1176811. PMC 2876822. PMID 19729652.