Pepticle synthesis with the N-nitroso derivatives of sarcosine and proline

1969 ◽  
Vol 22 (11) ◽  
pp. 2451 ◽  
Author(s):  
FHC Stewart
Keyword(s):  
Anomalous Behaviour ◽  
Protecting Group ◽  
Model Peptide ◽  
Colour Reaction ◽  
Derivatives Of

Various esters and salts of N-nitrososarcosine and N-nitroso-L-proline have been prepared, and used to provide amino and carboxyl components in model peptide syntheses. The sequential polypeptide (Sar-Gly)n was synthesized using the nitroso residue as an acid-sensitive protecting group. ��� Anomalous behaviour of some of the N-nitroso derivatives in the Liebermann colour reaction is also discussed.

Cleavage of the Epimines of 1,6-Anhydrohexoses with Fluoride Anion

2005 ◽  
Vol 70 (12) ◽  
pp. 2075-2085 ◽  
Author(s):  
Jiří Kroutil ◽  
Klára Jeništová
Keyword(s):  
Fluoride Anion ◽  
Ring Cleavage ◽  
Protecting Group ◽  
Reaction Conditions ◽  
Aziridine Ring ◽  
Cleavage Reactions ◽  
Derivatives Of ◽  
Fluoro Derivatives

Aziridine ring cleavage reactions of five N-nosylepimines (2-6) having D-talo, D-galacto, D-manno, and D-allo configurations with potassium hydrogendifluoride under various reaction conditions have been performed. The cleavage regioselectively afforded diaxial isomers of vicinal amino-fluoro derivatives of 1,6-anhydro-β-D-gluco- and mannopyranose 7-11 in 51-94% yields. Removal of 2-nitrobenzenesulfonyl protecting group with benzenethiol has been attempted in the case of compound 10.

scholarly journals Self-Supporting Hydrogels Based on Fmoc-Derivatized Cationic Hexapeptides for Potential Biomedical Applications

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 678
Author(s):  
Carlo Diaferia ◽  
Elisabetta Rosa ◽  
Enrico Gallo ◽  
Giovanni Smaldone ◽  
Mariano Stornaiuolo ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Supporting Cell ◽  
Diagnostic Tools ◽  
Cationic Peptides ◽  
Protecting Group ◽  
Synthetic Hydrogel ◽  
Acetyl Group ◽  
Biophysical Techniques ◽  
Fmoc Protecting Group ◽  
Derivatives Of

Peptide-based hydrogels (PHGs) are biocompatible materials suitable for biological, biomedical, and biotechnological applications, such as drug delivery and diagnostic tools for imaging. Recently, a novel class of synthetic hydrogel-forming amphiphilic cationic peptides (referred to as series K), containing an aliphatic region and a Lys residue, was proposed as a scaffold for bioprinting applications. Here, we report the synthesis of six analogues of the series K, in which the acetyl group at the N-terminus is replaced by aromatic portions, such as the Fmoc protecting group or the Fmoc-FF hydrogelator. The tendency of all peptides to self-assemble and to gel in aqueous solution was investigated using a set of biophysical techniques. The structural characterization pointed out that only the Fmoc-derivatives of series K keep their capability to gel. Among them, Fmoc-K3 hydrogel, which is the more rigid one (G’ = 2526 Pa), acts as potential material for tissue engineering, fully supporting cell adhesion, survival, and duplication. These results describe a gelification process, allowed only by the correct balancing among aggregation forces within the peptide sequences (e.g., van der Waals, hydrogen bonding, and π–π stacking).

Derivatives of 5α-androstan-3α- and 3β-ol with acrylate side chain

1990 ◽  
Vol 55 (5) ◽  
pp. 1243-1256 ◽  
Author(s):  
Vladimír Pouzar ◽  
Hana Chodounská ◽  
Dalibor Sameš ◽  
Pavel Drašar ◽  
Miroslav Havel
Keyword(s):  
Ethyl Esters ◽  
Side Chain ◽  
Protecting Group ◽  
Derivatives Of

Hydroxy derivatives I, II, III, XVII and XX were oxidized to give the respective aldehydes IV, V, VI, XVIII and XXI which were further converted by Wittig-Horner reaction into unsaturated methyl and ethyl esters. Removal of the acetal protecting group in position 3 afforded methylesters X, XXIV and XXXVI and ethyl esters XIV, XXV and XXXVII. Compounds XXIV, XXV, XXXVI and XXXVII were converted into the corresponding hemisuccinates XXVIII, XXIX, XL and XLI and β-D-glucosides XXXII, XXXIII, XLIV and XLV.

scholarly journals A new class of organogelators based on triphenylmethyl derivatives of primary alcohols: hydrophobic interactions alone can mediate gelation

2017 ◽  
Vol 13 ◽  
pp. 138-149 ◽  
Author(s):  
Wangkhem P Singh ◽  
Rajkumar S Singh
Keyword(s):  
Hydrophobic Interactions ◽  
Water Soluble ◽  
Protecting Group ◽  
Primary Alcohols ◽  
Alkyl Chains ◽  
New Class ◽  
Group A ◽  
Gelation Concentration ◽  
Xrd Techniques ◽  
Derivatives Of

In the present work, we have explored the use of the triphenylmethyl group, a commonly used protecting group for primary alcohols as a gelling structural component in the design of molecular gelators. We synthesized a small library of triphenylmethyl derivatives of simple primary alcohols and studied their gelation properties in different solvents. Gelation efficiency for some of the derivatives was moderate to excellent with a minimum gelation concentration ranging between 0.5–4.0% w/v and a gel–sol transition temperature range of 31–75 °C. 1,8-Bis(trityloxy)octane, the ditrityl derivative of 1,8-octanediol was the most efficient organogelator. Detailed characterizations of the gel were carried out using scanning electron microscopy, FTIR spectroscopy, rheology and powder XRD techniques. This gel also showed a good absorption profile for a water soluble dye. Given the non-polar nature of this molecule, gel formation is likely to be mediated by hydrophobic interactions between the triphenylmethyl moieties and alkyl chains. Possible self-assembled packing arrangements in the gel state for 1,8-bis(trityloxy)octane and (hexadecyloxymethanetriyl)tribenzene are presented. Results from this study strongly indicate that triphenylmethyl group is a promising gelling structural unit which may be further exploited in the design of small molecule based gelators.

Dimedone (5,5-Dimethylcyclohexane-1,3-dione) as a protecting agent for amino groups in peptide synthesis

1964 ◽  
Vol 17 (11) ◽  
pp. 1282 ◽  
Author(s):  
B Halpern ◽  
LB James
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Amino Acid Esters ◽  
Protecting Group ◽  
Amino Groups ◽  
Active Esters ◽  
Optically Pure ◽  
Derivatives Of ◽  
Protected Peptides ◽  
Acid Esters

The reaction of dimedone (5,5-dimethylcyclohexane-1,3-dione) with amino-acid "active" esters leads to optically pure enamine derivatives. The dimedone derivatives of amino acid esters could also be converted by way of their hydrazides to the corresponding azides. The thiophenyl ester and azide derivatives have been used directly for peptide synthesis. The protecting group can easily be removed from the N-protected peptides by means of aqueous bromine, with the formation of 2,2-dibromodimedone and the hydrobromide of the corresponding peptide ester.

Linear oligopeptides. 118. Preferred conformations and modes of self-association of the fluoren-9-ylmethoxycarbonyl amino acid derivatives

1984 ◽  
Vol 62 (12) ◽  
pp. 2661-2666 ◽  
Author(s):  
Giovanni Valle ◽  
Gian Maria Bonora ◽  
Claudio Toniolo
Keyword(s):  
Solid State ◽  
Amide Bond ◽  
Experimental Result ◽  
Carbonyl Groups ◽  
Protecting Group ◽  
X Ray Diffraction ◽  
Aminoisobutyric Acid ◽  
Self Association ◽  
Associated Species ◽  
Derivatives Of

An analysis of the preferred conformations and modes of self-association of the N-fluoren-9-methoxycarbonyl derivatives of L-alanine and α-aminoisobutyric acid was performed in solution and in the solid state using infrared absorption, 1H nuclear magnetic resonance, and X-ray diffraction. In a solvent of low polarity (deuterochloroform) non-associated and self-associated species (involving predominantly the hydroxyl and carbonyl groups of the carboxylic acid moiety) simultaneously occur. At high dilution, where self-association is absent, the amount of intramolecularly H-bonded forms, if any, should be extremely small. Z(trans) [Formula: see text]E(cis) isomerism about the amide bond of the secondary urethane moiety was observed only for the less bulky L-alanine derivative. In the solid state all H-bonding donors and acceptors of the L-alanine and α-aminoisobutyric acid derivatives take part to complex schemes of intermolecular H-bonds. In the L-alanine derivative, crystallized as monohydrate, most of the intermolecular H-bonds involve the water molecule. Intramolecular H-bonds are not observed in either compound. The conformation about the secondary urethane CO—NH bond is Z(trans) in both compounds. Both L-alanine and α-aminoisobutyric acid residues are partially folded. The observation of the long C(sp3)—O bond of the fluoren-9-yl-methoxycarbonyl moiety might contribute to explain the unexpected experimental result that this protecting group can be removed by catalytic hydrogenation.

The synthesis of oligoribonucleotides. III. The use of silyl protecting groups in nucleoside and nucleotide chemistry. VIII

1979 ◽  
Vol 57 (17) ◽  
pp. 2230-2238 ◽  
Author(s):  
Kelvin K. Ogilvie ◽  
Aria L. Schifman ◽  
Christopher L. Penney
Keyword(s):  
Protecting Groups ◽  
Protecting Group ◽  
Cautionary Note ◽  
Derivatives Of ◽  
Isomeric Mono

The synthesis of all isomeric mono- and disilyl derivatives of cytidine, guanosine, and their N-benzoyl analogues using the tert-butyldimethylsilyl protecting group is described. These compounds and those containing a 5′-monomethoxytrityl group have been condensed via the phosphodichloridite procedure to produce nucleotides rapidly and in good yields. The synthesis of 2′–5′-linked nucleotides is described. A cautionary note is introduced in regard to the preparation of 5′-monomethoxytritylguanosine and a novel methanolysis of certain N-benzoylcytidines is mentioned.

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