42977-21-9Relevant articles and documents
Oxidation chemistry of perfluoroalkyl-segmented thiols, disulfides, thiosulfinates and thiosulfonates: The role of the perfluoroalkyl group in searching out new chemistry
Brace, Neal O.
, p. 11 - 23 (2000)
The oxidation chemistry of perfluoroalkyl-segmented thiols, RF-R-SH (1), thiosulfinates, RF-R-S(O)S-R-RF (3), thiosulfonates, RF-R-S(O2)S-R-RF (4) and disulfides, RF-R-SS-R-RF (5) (in which RF=n-C6F13 or n-C8F17 and R=CH2CH2) is studied herein. Base catalyzed reaction of C6 thiol 1 with hydrogen peroxide gives pure disulfide 5, quantitatively. Other, less suitable methods for the oxidation of thiol 1 are also examined and compared. Selective oxidation of disulfide 5 by peroxy acids in chlorinated solvents gives excellent yields of thiosulfinate 3. Unlike their hydrocarbon analogues, which are unstable to heating or storage, the RF-segmented thiosulfinates 3 are relatively stable, crystalline compounds. Selective oxidation of 3 by sodium metaperiodate gives thiosulfonate 4 in high yield. Side reactions intervene with unfavorable conditions, or when peroxy acetic acid in acetic acid is used as oxidant,. Oxidation of 5 by hydrogen peroxide in low conversion gives 4 and two new compounds, 8 and 9. Compound 8 is n-C6F13S(O)2CH2CH2C 6F13 (probably the sulfinate ester and not the sulfone), and 9 is most likely the O,S-sulfenyl sulfinate or, possibly an isomer, the vic-disulfoxide. A free radical chain mechanism is proposed for conversion of 4 (or 9) to 8. Compounds 8 and 9 are stable in solution and are identified by MS/GC. In 3, 4 and 5, the ν CH bands correlate with NMR of CH2 at C(1) and C(2) positions, both 1H and 13C NMR. The RF-segment in these unique sulfur compounds enhances their utility and modifies their chemical and physical properties in important and interesting ways.
Exploiting Sm(ii) and Sm(iii) in SmI2-initiated reaction cascades: Application in a tag removal-cyclisation approach to spirooxindole scaffolds
Coote, Susannah C.,Quenum, Seidjolo,Procter, David J.
, p. 5104 - 5108 (2011/08/07)
A tag removal-cyclisation sequence is described that is initiated by reduction using a Sm(ii) species and completed by a Sm(iii) Lewis acid that is formed in an earlier stage. Therefore, the reaction cascade utilises both oxidation states of a samarium reagent in discrete steps and allows access to privileged, pyrrolidinyl-spirooxindole scaffolds and analogues inspired by the anti-cancer natural product spirotryprostatin A. The Royal Society of Chemistry 2011.
Preparation, reactions and physical properties of segmented 2-(perfluoroalkyl)ethanesulfinic acids and their derivatives. the role of the perfluoroalkyl group in finding new and useful compounds and in searching out new chemistry
Brace, Neal O.
, p. 21 - 41 (2007/10/03)
2-(Perfluoroalkyl)ethanesulfinic acids of the formula RFCH2CH2SO2H (2, where RF=n-C6F13, or n-C8F17) are synthesized from the thiol, RFCH2CH2SH (1). These segmented acids 2 have sharp melting point (mp) and can be recrystallized. The C6 or C8 perfluoroalkyl group confers unusual "fluophilic" properties to acids 2 and their derivatives. Water solutions of acids 2 and their Na, K, Cs and Bu4N salts are highly surface active and stable for several days, and are more effective in reducing surface tension at the air/water interface than sodium n-perfluorooctanesulfonate (10). Sodium salts 2 (C6, C8) are converted to K and Cs salts by methathesis in high yield. However, the amphiphilic Bu4N salts of 2 (C6, C8) are best prepared in a biphasic system (C6, 99.6% yield). Acids 2 are synthesized by three methods. (1) Oxidation of the C8 thiol 1 (at -35°C) by m-CPBA gives acid 2 (C8) in 73% yield and unwanted disulfide (3) in 27% yield. The bulky, strongly electronegative RF group of 1 may slow oxidation of the RSOH (intermediate) to allow disproportionation with RSH into disulfide 3 and water. (2) Hydrolysis of RFCH2CH2SO2SCH2CH 2RF (4) with strong base gives salt 2 (C6, or C8; 92% yield). (3) Heating sulfone, RFCH2CH2SO2CH2CH 2Y (8) with a base (M2CO3) eliminates RFCH2CH2SO2M (2, M=Na, K, Cs) in 95-100% yield (C6, C8). Alternatively, 8 with the sodium thiolate of 1 gives RFCnH2nSCH2CH2Y (7, 90%) and sodium salt 2 (C6, 95%). Conjugate addition of the RFCH2CH2SO2- to CH2CHY gives sulfones 8, and RFCH2CH2SO2- adds stereospecifically to cyclohexene oxide, giving the trans-adduct 13. RFCH2CH2SO2H (2), with azo initiator, telomerizes acrylamide to a water-soluble, surface active product.