- A Mild, General, Metal-Free Method for Desulfurization of Thiols and Disulfides Induced by Visible-Light
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A visible-light-induced metal-free desulfurization method for thiols and disulfides has been explored. This radical desulfurization features mild conditions, robustness, and excellent functionality compatibility. It was successfully applied not only to the desulfurization of small molecules, but also to peptides.
- Qiu, Wenting,Shi, Shuai,Li, Ruining,Lin, Xianfeng,Rao, Liangming,Sun, Zhankui
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supporting information
p. 1255 - 1258
(2021/05/05)
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- Desulfurization method of organic compounds containing mercapto or disulfide bond
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The invention relates to a desulfurization method of organic compounds, in particular, organic compounds containing mercapto or a disulfide bond. The method comprises following steps: dissolving organic compounds containing mercapto or a disulfide bond by a solvent; adding a phosphine reagent and an initiator; and carrying out reactions in the presence of light to convert the substrate into corresponding desulfurization products. The organic compounds containing mercapto or a disulfide bond is R-SH or R-S-S-R; wherein R represents a primary carbon group, a secondary carbon group, a tertiary carbon group, an aryl group, or an acyl group. The reactions do not need any metal, and the reaction conditions are mild. Moreover, the desulfurization method has the advantages of high yield, wide substrate application range, and multiple suitable solvents, and is widely suitable for multiple kinds of mercapto-removing reactions and desulfurization reactions of disulfide.
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Paragraph 0026
(2019/10/01)
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- Comparison of liquid chromatography-isotope ratio mass spectrometry (LC/IRMS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) for the determination of collagen amino acid δ13C values for palaeodietary and palaeoecological reconstruction
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Results are presented of a comparison of the amino acid (AA) δ13C values obtained by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) and liquid chromatography-isotope ratio mass spectrometry (LC/IRMS). Although the primary focus was the compound-specific stable carbon isotope analysis of bone collagen AAs, because of its growing application for palaeodietary and palaeoecological reconstruction, the results are relevant to any field where AA δ13C values are required. We compare LC/IRMS with the most up-to-date GC/C/IRMS method using N-acetyl methyl ester (NACME) AA derivatives. This comparison involves the analysis of standard AAs and hydrolysates of archaeological human bone collagen, which have been previously investigated as N-trifluoroacetyl isopropyl esters (TFA/IP). It was observed that, although GC/C/IRMS analyses required less sample, LC/IRMS permitted the analysis of a wider range of AAs, particularly those not amenable to GC analysis (e.g. arginine). Accordingly, reconstructed bulk δ13C values based on LC/IRMS-derived δ13C values were closer to the EA/IRMS-derived δ13C values than those based on GC/C/IRMS values. The analytical errors for LC/IRMS AA δ13C values were lower than GC/C/IRMS determinations. Inconsistencies in the δ13C values of the TFA/IP derivatives compared with the NACME- and LC/IRMS-derived δ13C values suggest inherent problems with the use of TFA/IP derivatives, resulting from: (i) inefficient sample combustion, and/or (ii) differences in the intra-molecular distribution of δ13C values between AAs, which are manifested by incomplete combustion. Close similarities between the NACME AA δ13C values and the LC/IRMS-derived δ13C values suggest that the TFA/IP derivatives should be abandoned for the natural abundance determinations of AA δ13C values.
- Dunn, Philip J. H.,Honch, Noah V.,Evershed, Richard P.
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p. 2995 - 3011
(2012/05/20)
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- The effect of substituents on the chiral solvating properties of (S)-1,6-dialkylpiperazine-2,5-diones
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The effect of substituents on the chiral solvating properties of 13 different (S)-1,6-dialkylpiperazine-2,5-diones (S)-1a-m and five (3S,6S)-1,3,6-trialkyl analogues (S,S)-1n-r was studied by NMR in CDCl 3 with methyl (RS)-N-benzoylleucinate (R
- Malavasic, Crt,Stanovnik, Branko,Wagger, Jernej,Svete, Jurij
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experimental part
p. 1364 - 1371
(2011/11/29)
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- ANTI-ODOR COMPOSITIONS AND THERAPEUTIC USE
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This application discloses a composition comprising a malodor compound and an anti-odor ingredient effective for reducing the presence or production of malodor. The composition may be topically applied to a subject and is useful for cosmetic conditions, pharmaceutical indications, or other objectives.
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- Use of enantio-, chemo- and regioselectivity of acylase I. Resolution of polycarboxylic acid esters
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Acylase I was used to catalyze the enantioselective butanolysis of trimethyl 2-[(carboxymethyl)oxy]succinate (E=30) and N-carboxymethylaspartate (E=9) exclusively at the most sterically hindered of the three ester groups (the position α to the asymmetric centre). Gram-scale resolution allowed the preparation of the less reactive trimethyl (S)-2-[(carboxymethyl)oxy]succinate (96% e.e.), that of the (R)-butyldimethyl regioisomer (78% e.e.) at 55% conversion and finally the preparation of the corresponding trisodium carboxylate by saponification. Acylase I was shown to transform (±)-methyl N-acetylmethionine and (±)-valine to the corresponding (S)-amino acids through ester hydrolysis-N-acetyl transfer sequence with absolute chemo- and enantioselectivity. Butanolysis of methyl N-acetylmethionine stopped in the formation of the butyl ester (E=12), the valine derivative being totally unreactive.
- Liljeblad, Arto,Aksela, Reijo,Kanerva, Liisa T.
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p. 2059 - 2066
(2007/10/03)
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- N-tert-butoxycarbonyl (BOC) deprotection using boron trifluoride etherate
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A mild and efficient procedure is described for the removal of the tert- butoxycarbonyl (BOC) group using boron trifluoride etherate and molecular sieves in dichloromethane at room temperature. The scope of this procedure is explored for the deprotection of a variety of amines including amino acid derivatives.
- Evans, Emily F.,Lewis, Norman J.,Kapfer, Isabelle,Macdonald, Gregor,Taylor, Richard J. K.
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p. 1819 - 1825
(2007/10/03)
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- Surprising Reactivity of (Methyl 2-Acetamidoacrylate)tricarbonyliron(0) leading to the Synthesis of β,β,β-Trialkyl α-Amino Acids
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Addition of methyllithium followed by tertiary haloalkanes to readily available and air-stable (methyl 2-acetamidoacrylate)tricarbonyliron(0) 1, gives protected β,β,β-trialkyl α-amino acids which are hydrolysed to give tert-leucine 10 and the new α-amino acids 2-amino-3,3-dimethylpentanoic acid 11 and 2-amino-3,3-dimethylhexanoic acid 12.
- Barker, James,Cook, Stephen L.,Lasterra-Sanches M. Elena,Thomas, Susan E.
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p. 830 - 832
(2007/10/02)
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- Efficient Asymmetric Hydrogenations of (Z)-2-Acetamidoacrylic Acid Derivatives with the Cationic Rhodium Complex of (2S,4S)-MOD-BPPM
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The preparation of (2S,4S)-MOD-BPPM ((2S,4S)-N-(t-butoxycarbonyl)-4-phosphino>-2-phosphino>methyl>pyrrolidine) and its application to highly effective asymmetric hydrogenations of (Z)-2-acetamidoacrylic acid derivatives are described.
- Takahashi, Hisashi,Achiwa, Kazuo
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p. 305 - 308
(2007/10/02)
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- Homogeneous Hydrogenation of Tetrasubstituted Alkene Moieties in Prochiral Didehydro Amino Acid Derivatives Catalysed by Iridium Complexes
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The hydrogenation of the tetrasubstituted alkene moieties of prochiral didehydro amino acid derivatives (1a and b), (2a and b), (3b), (+) and (-)-(6), (+)-(7), and (-)-(9) has been succesfully achieved under very mild homogeneous conditions (1 atm of H2;
- Cabeza, Javier A.,Cativiela, Carlos,de Villegas, Maria D. Diaz,Oro, Luis A.
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p. 1881 - 1884
(2007/10/02)
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- A general and accurate nmr determination of the enantiomeric purity of α-aminoacids and α-aminoacid derivatives
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Derivatization of α-aminoacids, α-aminoesters and α-aminolactones as N-acetyl derivatives allow the accurate NMR determination of the enantiomeric purity. In these conditions the major coordination site with a chiral shift reagent will correspond to the NMR observation site. Experimental factors leading to the highest ΔΔδ values are ascertained. No straightforward correlation with absolute configurations can be established.
- Calmes, Monique,Daunis, Jacques,Jacquier, Robert,Verducci, Jean
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p. 2285 - 2292
(2007/10/02)
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- Iridium-catalysed Homogeneous Hydrogenation of Prochiral Enamides Containing Tetrasubstituted Alkene Moieties
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The tetrasubstituted prochiral amido-alkenes (1a, b), (2a, b), and (3b) have been homogeneously hydrogenated under very mild conditions by iridium complexes of the type (cod = cyclo-octa-1,5-diene, bzn = benzonitrile, L = tricycloh
- Oro, Luis A.,Cabeza, Javier A.,Cativiela, Carlos,Villegas, Maria D. Diaz de,Melendez, Enrique
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p. 1383 - 1384
(2007/10/02)
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