A new protecting group for the sulfhydryl function of cysteine

Schroll, Alayne L.; Bárány, George

doi:10.1021/jo00262a051

Cited by 24 publications

(36 citation statements)

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“…While the ZumachÀK€ uhle review 1 alluded to a range of primary and secondary, aliphatic and aromatic carbamoyl moieties (legend to Scheme 1), we elected to study principally compounds based on N-methylaniline, especially because an extensive set of derivatives 13,14 were available in our laboratory that could be used as reference compounds in elucidating the subsequent chemistries. To facilitate and standardize spectroscopic characterization and comparisons, the described reactions (Scheme 2) were generally carried out in CDCl 3 solution, although for completeness, selected experiments were repeated in other aprotic solvents, specifically CD 3 CN, dioxane-d 8 , and benzene-d 6 . Outcomes of such experiments were similar, although kinetics varied, consistent with the range of polarities for the solvents tested.…”

Section: ' Introductionmentioning

confidence: 99%

Synthetic Routes to, Transformations of, and Rather Surprising Stabilities of (N-Methyl-N-phenylcarbamoyl)sulfenyl Chloride, ((N-Methyl-N-phenylcarbamoyl)dithio)carbonyl Chloride, and Related Compounds

2011

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The title compound classes, (carbamoyl)sulfenyl chlorides and ((carbamoyl)dithio)carbonyl chlorides, have been implicated previously as unstable, albeit trappable, intermediates in organosulfur chemistry. The present work reports for each of these functional groups: (i) several routes to prepare it in the N-methylaniline family; (ii) its direct structural characterization by several spectroscopic techniques; (iii) its rather unexpected stability and its ultimate fate when it decomposes; (iv) a series of further chemical transformations that give highly stable derivatives, each in turn subject to thorough characterization. Relevant kinetic and mechanistic experiments were carried out, including some with p-methyl- and 2,6-dimethyl-substituted N-methylanilines. Given that the title compounds can be isolated and are relatively stable, they may find applications in the preparation of thiolyzable and/or photolabile protecting groups for the sulfhydryl function of cysteine and for the development of new protein synthesis and modification reagents.

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Section: ' Introductionmentioning

confidence: 99%

Synthetic Routes to, Transformations of, and Rather Surprising Stabilities of (N-Methyl-N-phenylcarbamoyl)sulfenyl Chloride, ((N-Methyl-N-phenylcarbamoyl)dithio)carbonyl Chloride, and Related Compounds

2011

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“…A fare more versatile application was found in the thiolysis [24] of disulfides (e.g. 15), because the resulting 2-pyridyldisulfides 16 can be N-alkylated to Nalkylpyridinium disulfides 17, shown by the late D. H. R. Barton [25] to be potent sulfenyl transferring reagents.…”

Section: Methodsmentioning

confidence: 99%

2-Mercaptopyridine - anchimerically-assisted activation of thiols, thioates and ketene thioacetals

Schmidt¹,

Kühn

1999

J. prakt. Chem.

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Abstract. The 2-mercaptopyridine reagent is reviewed with particular emphasis on a) recent developments, and b) comparison to alternative and sometimes superior methodologies. The useful application to macrocyclization or carboxyl activation is limited to special cases featuring additional functionalities. More recently, the reagent was utilized for the stereoselective synthesis of substituted β-lactones, β-lactames and carbohydrates. Scheme 1The reaction mechanism was already lined out in Mukaiyama's first report. The reaction is assumed to proceed via thioate coordination of the Grignard reagent to give the reactive intermediate 5, which is further activated by the Lewis acid for attack by the nucleophile. The immediate delivery of the nucleophile to the carbonyl group gives the complex 6, slowing down further attack from nucleophiles. The stability of this complex 114

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“…It has been reported in the literature that the cysteinyl radical can abstract sulfur atoms yielding the CysSS · radical with a transi-ent absorption at λ ഠ 380 nm. We recorded 1 H NMR, 13 C NMR, and HMQC spectra. Thiyl radicals add quickly to double bonds in an anti-Markovnikov fashion.…”

Section: Photochemistry Of Boc؊cys(snm)؊ohmentioning

confidence: 99%

“…The tubes were fused and 1 H, 13 C, and HMQC NMR spectra were taken before and after the photolysis (Bruker, Avance DPX 200, 200.13 MHz and Bruker, Avance DRX 600, 600.13 MHz). The preparative photolysis was carried out with 0.6 W·s Ϫ1 for 1 h. Samples (0.04 mol/L) were poured in quartz NMR tubes and degassed by the use of a supersonic bath and the ''freeze-andpump'' technique.…”

Section: Calculationsmentioning

confidence: 99%

“…[6,7] Several techniques have been reported to monitor the radicals. A variety of molecules have been investigated, but the thiol protection group Snm [methyl-(phenyl)thiocarbamic acid] published by Barany et al, [13] which can be cleaved under mild thiolytic conditions, was found to be most suitable for this application. Thiyl radicals, such as the cysteinyl radical, show only very weak absorptions in the IR spectrum, and thus the direct detection of the cysteinyl radical by the comparatively insensitive step-scan technique is not possible.…”

Section: Introductionmentioning

confidence: 99%

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Snm as a Photolabile Protecting Group for the Cysteinyl Radical − Direct Evidence from Time‐Resolved IR and UV/Vis Spectroscopies

Kolano

Sander

2003

Eur J Org Chem

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The cysteinyl radical and the methyl(phenyl)thiocarbamic acid radical have been generated by laser flash photolysis (266 nm) of BOC−Cys(Snm)−OH in acetonitrile and characterized both by time‐resolved (IR and UV/Vis) and standard spectroscopic methods (UV, IR, and NMR). The mode of action of the Snm unit [methyl(phenyl)thiocarbamic acid] is similar to the so‐called “caging” technique. Cleavage of the disulfide bridge by irradiation is possible in acceptable quantum yields. Time‐resolved IR (TR‐IR) spectroscopic experiments using the step‐scan FTIR technique allowed the detection of the methyl(phenyl)thiocarbamic acid radical (νC=O = 1607.7 and 1579.3 cm−1), which has a lifetime of about 3 µs. Because of the weak absorptions in the IR spectrum and the tendency for fast recombination to BOC‐protected cystine, the cysteinyl radical cannot be monitored by TR‐IR spectroscopy. Time‐resolved UV/Vis spectroscopy revealed the formation of both of these radicals and permitted the determination of the decay rates of the methyl(phenyl)thiocarbamic acid radical in the presence of several quenchers. NMR spectroscopic studies of the photolysis of BOC−Cys(Snm)−OH allowed us to identify N‐methylaniline, carbonyl sulfide, and BOC‐protected cystine as the major products. This study clearly demonstrates that the thiol protection group Snm is a suitable photolabile protecting group. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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A new protecting group for the sulfhydryl function of cysteine

Cited by 24 publications

References 0 publications

Synthetic Routes to, Transformations of, and Rather Surprising Stabilities of (N-Methyl-N-phenylcarbamoyl)sulfenyl Chloride, ((N-Methyl-N-phenylcarbamoyl)dithio)carbonyl Chloride, and Related Compounds

Synthetic Routes to, Transformations of, and Rather Surprising Stabilities of (N-Methyl-N-phenylcarbamoyl)sulfenyl Chloride, ((N-Methyl-N-phenylcarbamoyl)dithio)carbonyl Chloride, and Related Compounds

2-Mercaptopyridine - anchimerically-assisted activation of thiols, thioates and ketene thioacetals

Snm as a Photolabile Protecting Group for the Cysteinyl Radical − Direct Evidence from Time‐Resolved IR and UV/Vis Spectroscopies

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