scholarly journals Direct amidation of unprotected amino acids using B(OCH2CF3)3

2016 ◽  
Vol 52 (57) ◽  
pp. 8846-8849 ◽  
Author(s):  
Rachel M. Lanigan ◽  
Valerija Karaluka ◽  
Marco T. Sabatini ◽  
Pavel Starkov ◽  
Matthew Badland ◽  
...  
Keyword(s):  
Amino Acids ◽  
Methyl Ether ◽  
Protecting Group ◽  
Borate Ester ◽  
Direct Amidation

A commercially available borate ester, B(OCH2CF3)3, can be used to achieve protecting-group free direct amidation of α-amino acids with a range of amines in cyclopentyl methyl ether.

The 4-(methylthio)phenyl ester for the synthesis of polypeptides of a known repeating sequence of amino acids. Synthesis of poly-(L-lysylglycyl)glycine 1-C14 ethyl ester hydrobromide

1970 ◽  
Vol 48 (16) ◽  
pp. 2509-2511 ◽  
Author(s):  
Brian J. Johnson ◽  
Donna S. Rea
Keyword(s):  
Amino Acids ◽  
Ethyl Ester ◽  
Title Compound ◽  
Ester Hydrochloride ◽  
Phenyl Ester ◽  
Protecting Group ◽  
High Dilution ◽  
Protective Groups ◽  
Protected Tetrapeptide

The synthesis of the tetrapeptide, N-t-butoxycarbonyl-ε-N-carbobenzoxy-L-lysylglycyl-ε-N-carbobenzoxy-L-lysylglycine 4-(methylthio)phenyl ester is described. The utility of this protective ester is shown by its easy conversion to the protected tetrapeptide 4-(methylsulfonyl)phenyl activated ester without decomposition. Removal of the N-butoxycarbonyl protecting group afforded the polymerizing unit, ε-N-carbobenzoxy-L-lysylglycyl-ε-N-carbobenzoxy-L-lysylglycine 4-(methylsulfonyl)phenyl ester. Polymerization of this material on the partially blocked monomer glycine-1-C14 ethyl ester hydrochloride, at a relatively high dilution, gave poly-(ε-N-carbobenzoxyl-L-lysylglycyl)glycine-1-C14 ethyl ester. The carbobenzoxy protective groups were removed to give the title compound.

Short protecting-group-free synthesis of 5-acetylsulfanyl-histidines in water: novel precursors of 5-sulfanyl-histidine and its analogues

2016 ◽  
Vol 14 (44) ◽  
pp. 10473-10480 ◽  
Author(s):  
Sylvain Daunay ◽  
Remi Lebel ◽  
Laurence Farescour ◽  
Jean-Claude Yadan ◽  
Irene Erdelmeier
Keyword(s):  
Amino Acids ◽  
Protecting Group ◽  
One Pot ◽  
Step Procedure ◽  
Sulfur Containing

Natural and novel sulfur-containing amino acids are preparedviaa new regioselective one-pot two-step procedure.

2,5-Dimethylphenacyl carbamate: a photoremovable protecting group for amines and amino acids

2007 ◽  
Vol 6 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Laxminarayana Kammari ◽  
Lukáš Plíštil ◽  
Jakob Wirz ◽  
Petr Klán
Keyword(s):  
Amino Acids ◽  
Protecting Group

A multigram-scale lower E-factor procedure for MIBA-catalyzed direct amidation and its application to the coupling of alpha and beta aminoacids

2015 ◽  
Vol 17 (7) ◽  
pp. 4016-4028 ◽  
Author(s):  
Solmaz Fatemi ◽  
Nicolas Gernigon ◽  
Dennis G. Hall
Keyword(s):  
Amino Acids ◽  
Carboxylic Acids ◽  
Direct Amidation

More economical conditions for direct amidation between amines and carboxylic acids, including α- and β-amino acids, have been optimized using the MIBA catalyst (5-methoxy-2-iodophenylboronic acid, 6).

scholarly journals Synthesis of Chiral Thiourea-Thioxanthone Hybrids

Synthesis ◽  
2017 ◽  
Vol 49 (23) ◽  
pp. 5238-5250 ◽  
Author(s):  
Florian Mayr ◽  
Lisa-Marie Mohr ◽  
Elsa Rodriguez ◽  
Thorsten Bach
Keyword(s):  
Amino Acids ◽  
Phenyl Isothiocyanate ◽  
Carboxyl Group ◽  
Amino Group ◽  
Protecting Group

Four different 1-aminocyclohexanes bearing a tethered thioxanthone group in the 2-position were prepared. The synthesis commenced with the respective N-protected β-amino acids, the carboxyl group of which was employed for the introduction of the thioxanthone moiety. After construction of the thioxanthone and protecting group removal, the conversion of the amino group into the respective thiourea was accomplished by treatment with N-3,5-bis(trifluoromethyl)phenyl isothiocyanate and yielded the title compounds in which the thioxanthone resides in different spatial positions relative to the thiourea motif. Overall yields varied between 20–35%.

The 2,2,2-Trichloroethyl Group for Carboxyl Protection During Peptide Synthesis

1973 ◽  
Vol 51 (2) ◽  
pp. 208-214 ◽  
Author(s):  
Bernard Marinier ◽  
Yoon C. Kim ◽  
Jean-Marie Navarre
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Peptide Synthesis ◽  
Optical Activity ◽  
Selective Removal ◽  
Acid Chlorides ◽  
Protecting Group

The 2,2,2-trichloroethyl esters of several N-carbobenzoxy-amino acids were prepared by reacting the corresponding acid chlorides with trichloroethanol and the carbobenzoxy groups were selectively removed by HBr–AcOH. The resulting esters were then coupled with various N-carbobenzoxy-amino acids or peptides using dicyclohexylcarbodiimide in acetonitrile to give N-carbobenzoxy-peptide trichloroethyl esters. The selective removal of the trichloroethyl protecting group was effected by reduction using zinc in acetic acid. The optical activity of the N-carbobenzoxy-peptides so obtained agreed well with the values reported in the literature. The overall results suggest that the 2,2,2-trichloroethyl group could be useful for carboxyl protection during peptide synthesis.

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