S-Sulfonation

In the presence of catalytic amounts of cysteine, or -mercapto-ethylamine, and oxygen, sodium sulfite converts the half-cystine and cysteine residues of proteins to the S-sulfonate derivatives. 

The S-sulfo derivative is stable at neutral and acidic pH. Sulfitolysis has been employed as a mild procedure for the cleavage of disulfide bonds in multi-chain proteins, as a preliminary to polypeptide fractionation, and also to provide a protective blocking group for the cysteinyl residue. The S-sulfo derivative is readily reduced back to the thiol by the addition of sulfhydryl compounds, e.g. -mercaptoethanol. 

The following sulfitolysis procedure is based upon the work of Chan (1968). 

The completeness of the reaction is best assessed by employing Na2 of known specific activity, and determining the incorpora- 

Chan (1968) describes the following procedure for the regeneration of free thiol groups. 

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Table 2. Volume, Value, and Growth of U.S. Sulfonated and Sulfated Surfactant Products by Class ...

Sulfonation Plant Operations and Gas Effluent. Standards governing U.S. sulfonation plant gas effluents differ depending on whether or not the plant is equipped with a H2SO4 scmbbing system for adsorption of SO gas (see Fig. 3). The installation of the SO adsorber system qualifies the plant as a sulfuric production plant which has stringent regulations. Limitations and typical effluent from the sulfonation system are as follows ... 

S-Sulfonate, 488 S-Sulfenylthiocarbonate, 488 S-3-Nitro-2-pyridinesulfenyl Sulfide, 489 S-[Tricarbonyl[1,2,3,4,5-7]]-2,4-cyclohexadien-1-yl]-iron(1+), 490 Oxathiolone, 490... 

The conditions adopted in this procedure favor the production of a-monosulfonate in a state of high purity at the expense of a high conversion of anthraquinone. A better conversion can be achieved by conducting the sulfonation at a higher temperature, or by using more oleum, but in either case there is a considerable increase in the amount of disulfonic acids formed. The extent of /3-sulfonation is not influenced greatly by the temperature, but is dependent chiefly on the amount of mercuric salt present in the solution. The amount specified corresponds approximately to the limit of solubility of the salt in the acid employed, and very little of the /3-acid is formed. As the potassium /S-sulfonate is more soluble than the a-salt, traces of this isomer are easily eliminated by crystallization. 

An unknown analytical response in lettuce was detected61 and thought to contain P and S. The initial GC/MS Cl CH4 data were dominated by ions at m/z 121, 197 and 291 (equation 40). The GC/MS Cl NH3 data, however, indicated that perhaps the molecule had a higher molecular weight of 306 (MH+ equal to m/z 307, cf. equation 40). Comparison with the Cl CH4 and Cl NH3 spectra of demeton-S- (199) and demeton-O-sulfones showed, however, that the retention time and mass spectra of the former only matched the unknown (except the omission of the ion at m/z 307). On another stationary phase (OV-101) limited mass scanning of the ion at m/z 121 revealed a second unknown (200) eluting at 4.2 min (the major unknown, i.e. demeton-S-sulfone at 3.0 min). The molecular weight of 200 was believed to be 306. Because of the presence of ions at m/z 121,... 

A final method of forming disulfide crosslinks between toxins and targeting molecules is the use of S-sulfonate formation using sodium sulfite (Na2SC>3) in the presence of sodium tetrathion-ate (Na2S40g). Tetrathionate reacts with sulfhydryls to form sulfenylthiosulfate intermediates (section 1.1.5.2). These derivatives are reactive toward other thiols to create disulfide linkages... 

Poly(arylether ketone), conducting, 7 524 Poly(aryl ether ketone)s, sulfonation reaction of, 23 717-718 Poly(di-n-alkylsilanes), thermochromic materials, 6 619... 

Disulfoton causes neurological effects in humans and animals. The mechanism of action on the nervous system depends on the metabolism of disulfoton to active metabolites. The liver is the major site of metabolic oxidation of disulfoton to disulfoton sulfoxide, disulfoton sulfone, demeton S-sulfoxide and demeton S-sulfone, which inhibit acetylcholinesterase in nervous tissue. These four active metabolites are more potent inhibitors of acetylcholinesterase than disulfoton. Cytochrome P-450 monooxygenase and flavin adenine dinucleotide monooxygenase are involved in this metabolic activation. The active metabolites ultimately undergo nonenzymatic and/or enzymatic hydrolysis to more polar metabolites that are not toxic and are excreted in the urine. 

Evidence further suggests that male rats eliminate disulfoton at a faster rate than females. This difference may be due to differences in absorption, metabolism, retention, excretion, or a combination of factors. The metabolic pathways of disulfoton are relatively well understood based on data from animal studies (Bull 1965 Lee et al. 1985 March et al. 1957 Puhl and Fredrickson 1975). Similar metabolites have been detected in the urine and tissues from humans exposed to disulfoton (Brokopp et al. 1981 Yashiki et al. 1990). One study suggests that a greater percentage of disulfoton sulfoxide is oxidized to demeton S-sulfoxide, rather than disulfoton sulfone to form demeton S-sulfone (Bull 1965). Additional studies in animals, designed to measure the rate and extent of absorption, distribution, and excretion of disulfoton after inhalation or dermal exposure would be useful for predicting the toxicokinetics of disulfoton in humans at an occupational or hazardous waste site. 

Gunnison, A. F., and E. D. Palmes. S-sulfonates in human plasma following inhalation of sulfur dioxide. Amer. Ind. Hyg. Assoc. J. 35 288-291, 1974. 

Postsulfonation of polymers to form PEMs can lead to undesirable side reactions and may be hard to control on a repeatable basis. Synthesis of sulfonated macromolecules for use in PEMs by the direct reaction of sulfonated comonomers has gained attention as a rigorous method of controlling the chemical structure, acid content, and even molecular weight of these materials. While more challenging synthetically than postsulfonation, the control of the chemical nature of the polymer afforded by direct copolymerization of sulfonated monomers and the repeatability of the reactions allows researchers to gain a more systematic understanding of these materials properties. Sulfonated poly(arylene ether)s, sulfonated poly-(imide)s, and sulfonated poly(styrene) derivatives have been the most prevalent of the directly copolymerized materials. 

Triflate 17 was treated with 60% fuming sulfuric acid to give S-sulfonate 42. Similarly, S -sulfonates 44-47, Se-sulfonate 48, and Te-sulfonate 49 were synthesized (Eq. 11). 

Aminonaphthol has been prepared by the reduction of 1.4-nitronaphthol by tin and hydrochloric acid 1 by the reduction with sodiiun amalgam of i,4-aminonaphthol-3,8-disul-fonic acid or 1,4-aminonaphthol-s-sulfonic acid by the action of phenylhydrazine on 1,4-nitrosonaphthol. The more usual preparative method has been to start with a-Naphthol Orange (Orange I) and reduce it with stannous chloride. ... 

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