scholarly journals 2-Sulphobenzyl, a new solubilizing and reversible protecting group for cysteine in proteins. Its scope and limitations

1979 ◽  
Vol 179 (1) ◽  
pp. 127-134 ◽  
Author(s):  
U T Rüegg ◽  
D Jarvis ◽  
J Rudinger
Keyword(s):  
Control Experiment ◽  
Acid Group ◽  
Water Soluble ◽  
Protecting Groups ◽  
Protecting Group ◽  
Isoelectric Precipitation ◽  
Mild Conditions ◽  
Sulphonic Acid Group ◽  
A Chain ◽  
Sodium Amide

S-2-Sulphobenzylcysteine and S-2-(sulphomethyl)benzylcysteine are prepared by alkylation of cysteine with omega-toluenesultone and 2,3-benzo-1,4-butanesultone respectively. Owing to the presence of the sulphonic acid group, these protected cysteine derivatives are extremely water-soluble and are stable to acid hydrolysis. The groups can be removed by treatment with sodium in liquid NH3. Reduction with tributylphosphine and simultaneous alkylation of insulin with toluenesultone under mild conditions (pH 8.3, aq. 50% propanol) gives the fully S-substituted derivatives in excellent yield; they can be separated by isoelectric precipitation of the S-sulphobenzylated B-chain. Treatment of the latter with sodium in liquid NH3 led simultaneously to the removal of the protecting groups and to the well-documented cleavage at the threonine-proline bond which can be prevented by addition of sodium amide. When deprotected A-chain was recombined with B-chain, insulin was isolated in the same yield and with the same degree of biological activity as that in the control experiment.

Thietanyl Protection in the Synthesis of 8-Substituted 1-Benzyl-3-methyl-3,7-dihydro- 1H-purine-2,6-diones

2020 ◽  
Vol 17 (7) ◽  
pp. 535-539
Author(s):  
Ferkat Khaliullin ◽  
Yuliya Shabalina
Keyword(s):  
Hydrogen Peroxide ◽  
Benzyl Chloride ◽  
Bromine Atom ◽  
Protecting Groups ◽  
15N Nmr ◽  
Protecting Group ◽  
Mild Conditions ◽  
Protective Groups ◽  
The Stability ◽  
Substituted 1

Aim and Objective: 1-Аlkyl-3,7-dihydro-1H-purine-2,6-diones containing no substituents in the N7 position can be synthesized only using protecting groups, for example, benzyl protection. However, in the case of synthesis of 1-benzyl-3,7-dihydro-1H-purine-2,6-diones, the use of benzyl protection may lead to simultaneous debenzylation of both N1 and N7 positions. Therefore, it is necessary to use other protective groups for the synthesis of 1-benzyl-3,7-dihydro-1H-purine-2,6-diones. Materials and Methods: 8-Bromo- and 8-amino-substituted 1-benzyl-3-methyl-3,7-dihydro-1H-purine-2,6-diones unsubstituted in the N7 position were synthesized with the use of thietanyl protecting group. The thietane ring was introduced via the reaction of 8-bromo-3-methyl-3,7-dihydro-1H-purine-2,6-dione with 2-chloromethylthiirane, giving rise to 8-bromo-3-methyl-7-(thietan-3-yl)-3,7-dihydro-1H-purine-2,6-dione. The subsequent alkylation with benzyl chloride yielded 1-benzyl-8-bromo-3-methyl-7-(thietan-3-yl)-3,7-dihydro-1H-purine-2,6-dione, which was oxidized with hydrogen peroxide to be converted to 1-benzyl-8-bromo-3-methyl-7-(1,1-dioxothietan- 3-yl)-3,7-dihydro-1H-purine-2,6-dione. This product reacted with amines to give 8-amino-substituted 1-benzyl-3- methyl-7-(1,1-dioxothietan-3-yl)-3,7-dihydro-1H-purine-2,6-diones. The reaction of 8-substituted 1-benzyl-3- methyl-7-(1,1-dioxothietan-3-yl)-3,7-dihydro-1H-purine-2,6-diones with sodium isopropoxide resulted in the removal of the thietanyl protection and afforded target 8-substituted 1-benzyl-3-methyl-3,7-dihydro-1H-purine-2,6- diones. The structures of the targets compounds have been deduced upon their elemental analysis and spectral data (IR, 1H NMR, 13C NMR and 15N NMR). Results and Discussion: A new 8-substituted 1-benzyl-3-methyl-3,7-dihydro-1H-purine-2,6-diones unsubstituted in the N7 position were synthesized using thietanyl protecting group. Conclusion: The present study described a new route to synthesize some new 1,8-disubstituted 3-methyl-3,7- dihydro-1H-purine-2,6-diones unsubstituted in the N7 position starting from available 8-bromo-3-methyl-3,7- dihydro-1H-purine-2,6-dione with use of thietanyl protecting group. The advantages of this protocol are the possibility of the synthesis of 1-benzyl-substituted 3,7-dihydro-1H-purine-2,6-diones, the stability of the thietanyl protecting group upon nucleophilic substitution by amines of the bromine atom in the position 8, as well as mild conditions, and simple execution of experiments.

scholarly journals An amine protecting group deprotectable under nearly neutral oxidative conditions

2018 ◽  
Vol 14 ◽  
pp. 1750-1757 ◽  
Author(s):  
Shahien Shahsavari ◽  
Chase McNamara ◽  
Mark Sylvester ◽  
Emily Bromley ◽  
Savannah Joslin ◽  
...  
Keyword(s):  
Aliphatic Amines ◽  
Protecting Groups ◽  
Protecting Group ◽  
Weak Base ◽  
Amino Groups ◽  
Mild Conditions

The 1,3-dithiane-based dM-Dmoc group was studied for the protection of amino groups. Protection was achieved under mild conditions for aliphatic amines, and under highly reactive conditions for the less reactive arylamines. Moderate to excellent yields were obtained. Deprotection was performed by oxidation followed by treating with a weak base. The yields were good to excellent. The new amino protecting group offers a different dimension of orthogonality in reference to the commonly used amino protecting groups in terms of deprotection conditions. It is expected to allow a collection of transformations to be carried out on the protected substrates that are unattainable using any known protecting groups.

γ-Phosphono-γ-lactones. The use of allyl esters as easily removable phosphonate protecting groups

1985 ◽  
Vol 63 (4) ◽  
pp. 823-827 ◽  
Author(s):  
Matthias Kamber ◽  
George Just
Keyword(s):  
Carboxylic Acids ◽  
Phosphonic Acid ◽  
Acid Group ◽  
Protecting Groups ◽  
Protecting Group ◽  
Phosphonic Acids ◽  
Phosphonic Acid Group ◽  
Allyl Esters

During the synthesis of γ-lactones bearing a phosphonic acid group at the γ-position, difficulties were encountered generating the free phosphonic acids from corresponding esters. A protecting group used for carboxylic acids was adapted to phosphonic acids, making this transformation easy.

Insulin peptides. I. Some protected peptides with sequences derived from the A-chain of ovine insulin

1967 ◽  
Vol 20 (9) ◽  
pp. 1991 ◽  
Author(s):  
FHC Stewart
Keyword(s):  
Protecting Groups ◽  
Protecting Group ◽  
Protected Tetrapeptide ◽  
A Chain ◽  
Protected Peptides

Syntheses are described of two pentapeptide derivatives with the A5-9 and A17-21 sequences, respectively, of ovine insulin, and of a protected tetrapeptide with a modified A1-4 sequence. Preparation of the three compounds involved the use of the 2,4,6-trimethylbenzyl carboxyl-protecting group in conjunction with the o-nitrophenylsulphenyl and benzyloxycarbonyl amino-protecting groups.

scholarly journals Electronic and Assembly Properties of a Water-Soluble Blue Naphthalene Diimide

2021 ◽  
Author(s):  
Thomas Welsh ◽  
Olga Matsarskaia ◽  
Ralf Schweins ◽  
Emily Rose Draper
Keyword(s):  
Careful Consideration ◽  
Water Soluble ◽  
Mild Conditions ◽  
Deep Blue ◽  
Naphthalene Diimide

Herein we report on the synthesis and characterisation of a water soluble deep blue naphthalene diimide, (iPrNH)2NDI‒V. The synthesis is performed under mild conditions and careful consideration of the purification...

Synthesis of oxytocin, arginine-vasopressin and its deamino-analogue using 2,4,6-trimethylbenzyl group for protection of the cysteine sulfur

1981 ◽  
Vol 46 (1) ◽  
pp. 286-299 ◽  
Author(s):  
František Brtník ◽  
Milan Krojidlo ◽  
Tomislav Barth ◽  
Karel Jošt
Keyword(s):  
Peptide Synthesis ◽  
Hydrogen Fluoride ◽  
Sulfur Atom ◽  
Arginine Vasopressin ◽  
Liquid Hydrogen ◽  
Trifluoromethanesulfonic Acid ◽  
Protecting Groups ◽  
Mild Conditions

Preparation of oxytocin, arginine-vasopressin and its deamino-analogue serves as an example of use of 2,4,6-trimethylbenzyl group for protection of the cysteine sulfur atom in the peptide synthesis. This modified benzyl group is sufficiently stable under conditions of solvolytic removal of common amino-protecting groups and it can be cleaved off under mild conditions with liquid hydrogen fluoride or trifluoromethanesulfonic acid.

Bioinspired and Multifunctional Phospholipid Polymer Nanoparticles

2016 ◽  
Vol 102 ◽  
pp. 3-11
Author(s):  
Kazuhiko Ishihara ◽  
Wei Xin Chen ◽  
Yuuki Inoue
Keyword(s):  
Acid Group ◽  
Covalent Bonding ◽  
Water Soluble ◽  
Polymer Nanoparticles ◽  
Butyl Methacrylate ◽  
Carboxylic Acid Group ◽  
Cleavage Reaction ◽  
Phospholipid Polymer ◽  
Biodegradable Poly ◽  
Immobilized Proteins

Photoreactive and cytocompatible polymer nanoparticles for immobilizing and photoinduced releasing proteins were prepared. A water-soluble and amphiphilic phospholipid polymer, poly (2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate (BMA)-co-4-(4-(1-methacryloyloxyethyl)-2-methoxy-5-nitrophenoxy) butyric acid (PL)) (PMB-PL) was synthesized. The PMB-PL underwent a cleavage reaction at the PL unit by photoirradiation at a wavelength of 365 nm. Additionally, the PMB-PL took polymer aggregate in aqueous medium and was used to modify the surface of biodegradable poly (L-lactic acid) (PLA) nanoparticle as an emulsifier. The morphology of the PMB-PL/PLA nanoparticle was spherical and approximately 130 nm in diameter. The carboxylic acid group in the PL unit could be used for immobilization of proteins by covalent bonding. The bound proteins were released by a photoinduced cleavage reaction. Within 60 sec, up to 90% of the immobilized proteins were released by photoirradiation and activity of the protein released in the medium was maintained as well as that the original proteins before immobilization. Octa-arginine (R8) could promote internalization of the protein/PLA/PMB-PL nanoparticles into cells when the R8 was co-immobilized on the nanoparticles. After that, photoirradiation induced protein release from the nanoparticles and proteins distributed more evenly inside cells. From these results, we concluded that PMB-PL/PLA nanoparticles have the potential to be used as smart carriers to deliver proteins to biological systems, such as the inside of living cells.

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