Organic Disulfides and Related Substances. VIII. Preparation and Oxidation of Some Unsymmetrical Dialkyl and Alkyl Pyridinium Disulfides<sup>1</sup>

Field, Lamar; Härle, Horst; Owen, Terence C.; Ferretti, Aldo

doi:10.1021/jo01029a510

Cited by 28 publications

(10 citation statements)

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“…Such an observation probably precludes any triflinic acid-based strategy for the synthesis of thio- or selenoesters of triflic acid. ,, Likewise, the oxidation of phenyl trifluoromethyl disulfide does not seem suited to our purpose since it would probably deliver CF 3 SSO 2 Ph rather than CF 3 SO 2 SPh. , …”

Section: Resultsmentioning

confidence: 99%

A New Route to Thio- and Selenosulfonates from Disulfides and Diselenides. Application to the Synthesis of New Thio- and Selenoesters of Triflic Acid

et al. 1996

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Alkyl and aryl trifluoromethanethiosulfonates(1) (or selenosulfonates) were prepared in one step either from alkyl and aryl sulfenyl (or selenenyl) chlorides and sodium trifluoromethanesulfinate (3) or, more generally, from disulfides (or diselenides), 3, and bromine. The second method involved trifluoromethanesulfonyl bromide as key intermediate. Benzenethiosulfonates were obtained in a similar way from disulfides, benzenesulfinate, and bromine but benzeneselenosulfonates could not be obtained by the same method from diselenides.

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Section: Resultsmentioning

confidence: 99%

A New Route to Thio- and Selenosulfonates from Disulfides and Diselenides. Application to the Synthesis of New Thio- and Selenoesters of Triflic Acid

et al. 1996

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“…A doubly positively charged thiosulfonate, 2-aminoethyl-2-aminoethanethiosulfonate, NH 3 + CH 2 CH 2 SO 2 SCH 2 CH 2 NH 3 + (AEAETS), adds the 2-aminoethylthio group to the Cys −SH, just like MTSEA. It was synthesized as previously described ( Field et al, 1961 , 1964 ). It was recrystallized by dissolving in methanol, adding about one-third volume of diethyl ether, and storing at 4°C for 2 d. By thin-layer chromatography on cellulose, developed in 60% ethanol/30% 0.1 N HCl/10% t-butanol, the product in methanol gave one ninhydrin-positive spot with an R f = 0.26.…”

Section: Methodsmentioning

confidence: 99%

State-dependent Accessibility and Electrostatic Potential in the Channel of the Acetylcholine Receptor

Pascual

Karlin

1998

The Journal of General Physiology

109

107

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Ion channel function depends on the chemical and physical properties and spatial arrangement of the residues that line the channel lumen and on the electrostatic potential within the lumen. We have used small, sulfhydryl-specific thiosulfonate reagents, both positively charged and neutral, to probe the environment within the acetylcholine (ACh) receptor channel. Rate constants were determined for their reactions with cysteines substituted for nine exposed residues in the second membrane-spanning segment (M2) of the α subunit. The largest rate constants, both in the presence and absence of ACh, were for the reactions with the cysteine substituted for αThr244, near the intracellular end of the channel. In the open state of the channel, but not in the closed state, the rate constants for the reactions of the charged reagents with several substituted cysteines depended on the transmembrane electrostatic potential, and the electrical distance of these cysteines increased from the extracellular to the intracellular end of M2. Even at zero transmembrane potential, the ratios of the rate constants for the reactions of three positively charged reagents with αT244C, αL251C, and αL258C to the rate constant for the reaction of an uncharged reagent were much greater in the open than in the closed state. This dependence of the rate constants on reagent charge is consistent with an intrinsic electrostatic potential in the channel that is considerably more negative in the open state than in the closed state. The effects of ACh on the rate constants for the reactions of substituted Cys along the length of αM2, on the dependence of the rate constants on the transmembrane potential, and on the intrinsic potential support a location of a gate more intracellular than αThr244.

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“…This was prepared from 2 thiopyridone and 2aminoethyl 2'-aminoethanethiolsulphonate by the Vol. 151 method of Field et al (1964). The product was obtained in 70% yield and had m.p.…”

Section: -Aminoethyl-2'-pyridyl Disulphide Hydrochloridementioning

confidence: 99%

A reporter group delivery system with both absolute and selective specificity for thiol groups and an improved fluorescent probe containing the 7-nitrobenzo-2-oxa-1,3-diazole moiety

Stuchbury¹,

Shipton²,

Norris³

et al. 1975

Biochemical Journal

205

130

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1. 4-(N-2-Aminoethyl2'-pyridyl disulphide)-7-nitrobenzo-2-oxa-1,3-diazole (compound I) was synthesized and evaluated as a fluorescent labelling reagent for thiol groups. 2. The design of compound (I) as one example of a general type of reporter group delivery reagent (2-pyridyl-S-S-X, where X contains an environmentally sensitive spectroscopic probe) is discussed. 3. The electronic absorption spectrum of compound (I) was determined over a wide range of pH and the spectral changes that accompany its reaction with low-molecular-weight thiols, e.g. L-cysteine, and with papain (EC 3.4.22.2) and bovine serum albumin are discussed. 4. A new value of epsilon343 for 2-thiopyridone (Py-2-SH) was determined as 8.08 X 10(3) +/- 0.08 X 10(3)M-1-cm-1. 5. Spectral analysis of the reactions of compound (I) with L-cysteine and with papain (in the pH range 3.5-8.0) showed that even under equimolar conditions the reaction (thiol-disulphide interchange to release Py-2-SH) is essentially stoicheimoetric and probably proceeds by specific attack at the sulphur atom distal from the pyridyl ring of compound (I). 6. The fluorescence-emission spectra of compound (I) and of the products of its reaction with papain and with ficin (EC 3.4.22.3) were determined. Compound (I) is highly fluorescent in aqueous solution. Excitation within the intense visible absorption band (lambda max. 481 nm, epsilon max. 2.52 X 10(4)M-1-cm-1) provides green fluorescence with an emission maximum at 540 nm. Both papain and ficin labelled by reaction with compound (I) are characterized by fluorescence-emission maxima (535 nm and 530 nm respectively) of even higher intensity. The fluorescence emission of the product of the reaction of papain with compound (I) was shown to be 25 times more intense than that of the product of the reaction of papain with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (Nbd chloride). 7. The second-order rate constants (k2) for the reactions of compound (I) and of Nbd chloride with GSH, papain, albumin, ficin, 2-benzimidazolylmethanethiol and 2-benzimidazolylethanethiol were determined at 25.0 degrees C and various pH values. At pH4 the values of k2(compound I)/k2(Nbd chloride) are: GSH, 288; albumin, 36; papain 3 X 10(3); ficin, 3 X 10(4). 8. The pH-k2 profiles for the reactions of compound (I) and of Nbd chloride with the two 2-benzimidazolylalkanethiols were determined. Of the four profiles only that for the reaction of compound (I) with 2-benzimidazolylmethanethiol is characterized by a striking rate maximum in acidic media.

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Organic Disulfides and Related Substances. VIII. Preparation and Oxidation of Some Unsymmetrical Dialkyl and Alkyl Pyridinium Disulfides¹

Cited by 28 publications

References 0 publications

A New Route to Thio- and Selenosulfonates from Disulfides and Diselenides. Application to the Synthesis of New Thio- and Selenoesters of Triflic Acid

A New Route to Thio- and Selenosulfonates from Disulfides and Diselenides. Application to the Synthesis of New Thio- and Selenoesters of Triflic Acid

State-dependent Accessibility and Electrostatic Potential in the Channel of the Acetylcholine Receptor

A reporter group delivery system with both absolute and selective specificity for thiol groups and an improved fluorescent probe containing the 7-nitrobenzo-2-oxa-1,3-diazole moiety

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Organic Disulfides and Related Substances. VIII. Preparation and Oxidation of Some Unsymmetrical Dialkyl and Alkyl Pyridinium Disulfides1

Cited by 28 publications

References 0 publications

A New Route to Thio- and Selenosulfonates from Disulfides and Diselenides. Application to the Synthesis of New Thio- and Selenoesters of Triflic Acid

A New Route to Thio- and Selenosulfonates from Disulfides and Diselenides. Application to the Synthesis of New Thio- and Selenoesters of Triflic Acid

State-dependent Accessibility and Electrostatic Potential in the Channel of the Acetylcholine Receptor

A reporter group delivery system with both absolute and selective specificity for thiol groups and an improved fluorescent probe containing the 7-nitrobenzo-2-oxa-1,3-diazole moiety

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Organic Disulfides and Related Substances. VIII. Preparation and Oxidation of Some Unsymmetrical Dialkyl and Alkyl Pyridinium Disulfides¹