Sulfonation, oxidative

Pigment Blue 24 [6548-12-5] 42090 1 triarylcarbonium Ba salt (Peacock Blue) condensation of ben2aldehyde-(9-sulfonic acid with /V-ethy1-/V-hen2y1 aniline, followed by sulfonation, oxidation, and salt formation... 

The oxidation of thiophene and its derivatives with H202 was studied using a Ti-Beta molecular sieve. The oxidation product is very dependent from the aromaticity of model compounds. The thiophene oxidation product was mostly sulfates and the benzothiophene oxidation product was benzothiophene sulfone. Oxidation of mono and di-alkyl thiophenes also produced sulfates and sulfones. The diffusivity and aromaticity of the relevant sulfur compounds, intermediates and stable product, as well as the proposed new mechanism of oxidation will be discussed. This proposed new reaction pathway is different from current literature, which reports the formation of sulfones as a stable oxidation product. 

Buynak et al. [53] synthesized several 6-(mercaptomethyl) penicillanates (9r and 9s, Table 1) that include both C-6 stereoisomers as well as the sulfide and sulfone oxidation states of the penam thiazolidine sulfur. Selected mercaptomethyl penicillanates inactivated both metallo- and serine /5-lactamases, and displayed synergism with piperacillin against various //-lactamase-producing strains, including metallo-/5-lactamase-producing P. aeruginosa strain. Compound 9r would be capable of bidentate chelation of zinc subsequent to enzymatic hydrolysis of the /5-lactam (Scheme 3). 

It is obtained by condensing benzaldehyde-o-sulfonic acid with 2 equivalents of N-ethylbenzylaniline, followed by sulfonation, oxidation, and conversion to the ammonium salt. The dissolved dye is then immersed in a dispersion of aluminum hydroxide and converted to the corresponding salt using aluminum chloride or barium chloride solution ... 

Scheme 8 summarizes the introduction of the missing carbon atoms and the diastereoselective epoxidation of the C /C double bond using a Sharpless asymmetric epoxidation (SAE) of the allylic alcohol 64. The primary alcohol 62 was converted into the aldehyde 63 which served as the starting material for a Horner-Wadsworth-Emmons (HWE) reaction to afford an E-configured tri-substituted double bond. The next steps introduced the sulfone moiety via a Mukaiyama redox condensation and a subsequent sulfide to sulfone oxidation. The sequence toward the allylic alcohol 64 was com-... 

These sulfomethylated and sulfonated oxidized asphaltenes even remain in solution after acidification with 5% aqueous hydrochloric acid to a pH of 2.5-3.0 while the parent-oxidized asphaltenes can be precipitated from alkaline solution by acidification to a pH of 6.5. 

Cephalosporins in the sulfoxide or sulfone oxidation states can easily be obtained by treatment with different oxidants. This sulfur oxidation is usually accomplished for one of the following reasons (1) sulfoxide formation to obtain reactive intermediates for further transformations (2) sulfoxide formation with subsequent reduction in cephems to shift the double bond from position 2 to position 3 (3) preparation of sulfones as /3-lactamase or elastase inhibitors. 

The architecturally novel macrolide (+)-zampanolide was synthesized in the laboratory of A.B. Smith. The C8-C9 ( )-olefin moiety was constructed using the Kocienski-modified Julia oleHnation. The required PT-sulfone was prepared from the corresponding primary alcohol via a two-step protocol employing sequential Mitsunobu reaction and sulfide-sulfone oxidation. The primary alcohol and two equivalents of 1-phenyl-1 H-tetrazolo-5-thiol was dissolved in anhydrous THF at 0 °C and treated sequentially with triphenylphosphine and DEAD. The desired tetrazolo sulfide was isolated in nearly quantitative yield. 

The reactivity of the functional group is said to be independent of the molecular weights of the polymer. Polymers undergo chemical reactions as simple compounds which can generally be called low-molecular weight compounds except that in the former the reactants can be delivered to the sites of reactions. The main chemical reactions that rubbers undergo are nitration, sulfonation, oxidation, reduction and vulcanisation. 

The generally accepted mechanism for Pd-catalyzed allylic desulfonylations is illustrated in Scheme 1. The first step is coordination of the Pd(0) catalyst to the allylic sulfone. Oxidative addition or internal SN2-type nucleophilic attack of the electron-rich palladium at the allylic position generates a neutral Pd(II) r 3-allyl complex, which leads to a more reactive cationic complex that is finally reduced. The equilibrium between the neutral and the more reactive cationic complexes depends on the nature and concentration of the palladium ligands as well as the counter anions present in solution. 

In their second paper, Denison and Condit tracked the destruction of peroxides by dialkyl sulfides and sulfoxides and found that the former caused the rapid disappearance of peroxides until the sulfide had been converted to sulfoxide, and thereafter the slower rate of disappearance was identical to that caused by the sulfoxides.19 These authors also found that oxidation of the sulfoxide produced strong acids, which they conjectured were likely sulfonic acids. These acids can cause ionic decomposition of peroxides and this suggests a second route for interrupting the oxidation chain. In contrast, the dialkyl sulfones oxidized by a different route to produce weak—probably carboxylic—acids. 

Beyond the deprotonation studies discussed above, only the oxidation of ring sulfurs to the sulfone oxidation state, effected by treatment with either 5% peracetic acid (91) <89Mi 922-01) or 30% H2O2 (89 R = Ph) <81BCJ493), has been reported. 

Depending on the desired application, chemical modification of NCC can be carried out at the hydroxyl groups of the glucose units on the crystalline backbone structure [115]. Some reactions to accomplish such modifications include sulfonation, oxidation [115, 123], catlonization [115, 124], grafting [115, 125] (via acid chloride [115, 126], acid anhydride [115, 127], isocyanate [115, 128], and silylation [115,129] (Fig. 3.8). 

Sulfonation oxidation of hydrocarbon is similar to sulfonation-chlorination of hydrocarbon. Alkyl sulfonic acid can be synthesized under ultraviolet radiation by adopting saturated hydrocarbon, SO2, and O2 as raw materials. The reaction can be given by the following ... 

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