Protection of cysteine and histidine by the diphenyl-4-pyridylmethyl group during peptide synthesis

Coyle, Susan; Young, Geofrey T.

doi:10.1039/c39760000980

Cited by 12 publications

(3 citation statements)

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“…sulfur-protecting group) capable of forming a stabilized species upon cleavage of the bond between the S-atom and itself may yield a sulfenyl iodide iii, and hence a disulfide5). In the meantime, it has been shown that the following S-protected cysteine derivatives can be directly converted to cystine by iodine: S-benzamidomethyl-[ 18-20], S-tetrahydropyranyl- [21], S(5-dibenzo)suberyl- [22], and S-diphenyl(4-pyridy1)methyl-cysteine [23].…”

Section: -60b)mentioning

confidence: 99%

The Synthesis of Cystine Peptides by Iodine Oxidation of S‐Trityl‐cysteine and S‐Acetamidomethyl‐cysteine Peptides

Kamber

Hartmann

Eisler

et al. 1980

Helvetica Chimica Acta

277

171

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SummaryPreviously reported studies of the iodine oxidation of S-trityl-cysteine peptides and S-acetamidomethyl-cysteine peptides, leading directly to cystine peptides, have been extended. Detailed investigations have been made of the reactivities of the S-trityl and the S-acetamidomethyl group towards iodine in various solvents. In chloroform, methylene chloride, trifluoroethanol, and hexafluoroisopropyl alcohol the differences in the reaction rates of the two groups have been found to be extremely large, allowing the selective conversion of the tritylthio groups to disulfides in the presence of the S-acetamidomethyl derivatives. In a second group of solvents, consisting of methanol, acetic acid, dioxane, and mixtures of these solvents with water, simultaneous iodine oxidation of S-trityl-and S-acetamidomethyl-cysteine peptides leads to a preferential combination of these two residues, resulting in predominantly asymmetrical cystine derivatives. -The suitability of the two sulfur-protecting groups in the synthesis of cyclic cystine peptides has been assessed. -Possible reaction mechanisms are discussed. -The scope and limitations of iodine oxidation in peptide synthesis have been studied.The applicability of the method has been demonstrated in the preparation of the open-chain asymmetrical cystine peptide 5, the protected somatostatin derivative 17, and the A(l-13) segment 19 of human insulin, previously employed in the total synthesis of this hormone.Some years ago, we reported that S-trityl-cysteine peptides and S-acetamidomethyl-cysteine peptides [2] could be directly converted into cystine peptides by oxidation with iodine [3] [4]. In the meantime, this method has been applied by us and by others to the synthesis of a variety of structurally different cystine peptides PI ~61. I)Abbreviations are according to the IUPAC-IUB Commission on Biochemical Nomenclature [I]. In addition, the following abbreviations have been adopted in the text: Acm = acetamidomethyl; HFIP= hexafluoroisopropyl alcohol; TFE= trifluoroethanol; DMF = dimethylformamide.

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Section: -60b)mentioning

confidence: 99%

The Synthesis of Cystine Peptides by Iodine Oxidation of S‐Trityl‐cysteine and S‐Acetamidomethyl‐cysteine Peptides

Kamber

Hartmann

Eisler

et al. 1980

Helvetica Chimica Acta

277

171

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“…These include methionine ethyl ester-based polymers and various cysteine ethyl ester derivatives in which the S-H units were first protected, before linkage of the side groups to the phosphazene skeleton, and then deprotected to form the free thiol derivatives. [21][22][23][24][25] Experimental Section Reagents and Equipment. All synthesis reactions were carried out under a dry argon atmosphere using standard Schlenk line techniques except when aqueous solutions were used.…”

Section: Introductionmentioning

confidence: 99%

“…In this study we have synthesized several novel polyphosphazenes with sulfur-containing amino acid ester side groups. These include methionine ethyl ester-based polymers and various cysteine ethyl ester derivatives in which the S−H units were first protected, before linkage of the side groups to the phosphazene skeleton, and then deprotected to form the free thiol derivatives. − …”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Methionine- and Cysteine-Substituted Phosphazenes

et al. 2010

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The preparation of phosphazenes that possess reversible cross-linking groups to control mechanical stability and hydrolysis has been accomplished using cysteine and methionine amino acid side groups. Small molecule models and linear polymeric phosphazenes that contain methionine ethyl ester and cysteine ethyl disulfide ethyl ester side groups were synthesized. Protection of the free thiol groups was carried out to circumvent unwanted cross-linking of the phosphazenes through the cysteine ethyl ester N- and S-termini. Cyclic trimeric cysteine ethyl disulfide ethyl ester model compounds were deprotected by S−S bond cleavage using β-mercaptoethanol, dithiothreitol (DTT), and zinc in aqueous hydrochloric acid. For the high polymeric derivatives, the extent of S−S bond cleavage varied depending on the deprotection method used. With the exception of the Zn/HCl method, the resultant deprotected polymers were soluble in common organic solvents and underwent minimal chain cleavage during the reaction sequence. The protected or deprotected high polymers are candidates for reversible cross-linking in drug delivery systems and for cross-link stabilization of tissue engineering scaffolds.

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Protection for the Thiol Group

Greene¹,

Wuts

1999

Protective Groups in Organic Synthesis

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Protection of cysteine and histidine by the diphenyl-4-pyridylmethyl group during peptide synthesis

Cited by 12 publications

References 0 publications

The Synthesis of Cystine Peptides by Iodine Oxidation of S‐Trityl‐cysteine and S‐Acetamidomethyl‐cysteine Peptides

The Synthesis of Cystine Peptides by Iodine Oxidation of S‐Trityl‐cysteine and S‐Acetamidomethyl‐cysteine Peptides

Synthesis and Characterization of Methionine- and Cysteine-Substituted Phosphazenes

Protection for the Thiol Group

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