N-ACYLATED AMINO ACID IMINO CHLORIDES AND A QUALITATIVE STUDY OF RING CLOSURE AMONG N-ACYLAMINO ACID CHLORIDES

1957 ◽  
Vol 35 (9) ◽  
pp. 1031-1038 ◽  
Author(s):  
Edward Ronwin
Keyword(s):  
Amino Acid ◽  
Nitrogen Atom ◽  
Ring Closure ◽  
Acid Chlorides ◽  
Reaction Intermediates ◽  
Open Chain ◽  
Imino Acid ◽  
Infrared Spectral ◽  
Salt Forms ◽  
Predominant Product

Products have been isolated from the treatment of N-acylaminoacetonitriles with dry hydrogen chloride which are either the open-chain imino acid chlorides or the dissociated salt forms. These compound types have often been postulated as reaction intermediates but never isolated with an unsubstituted nitrogen atom. In the unsubstituted condition they are analogous to regular or oxygen acid chlorides.Several N-acylamino acids were treated with PCl5 and the reaction solutions were subjected to infrared spectral analyses. The results indicate that the open-chain acid chloride, rather than the azlactone salt, is the predominant product obtained with the compounds used in this investigation.

Eco-Friendly Synthesis of Peptides Using Fmoc-Amino Acid Chlorides as Coupling Agent Under Biphasic Condition

2020 ◽  
Vol 27 ◽  
Author(s):  
Santosh Y. Khatavi ◽  
K. Kantharaju
Keyword(s):  
Amino Acid ◽  
Acid Chloride ◽  
Acid Ester ◽  
Analytical Techniques ◽  
Peptide Bond ◽  
Amino Acid Ester ◽  
Acid Chlorides ◽  
Peptide Bond Formation ◽  
Green Protocol ◽  
Additional Base

Background: Agro-waste derived solvent media act as a greener process for the peptide bond formation using Nα - Fmoc-amino acid chloride and amino acid ester salt with in situ neutralization and coupling under biphasic condition. The Fmoc-amino acid chlorides are prepared by the reported procedure of freshly distilled SOCl2 with dry CH2Cl2. The protocol found many added advantages such as neutralization of amino acid ester salt and not required additional base for the neutralization, and directly coupling take place with Fmoc-amino acid chloride gave final product dipeptide ester in good to excellent yields. The protocol occurs with complete stereo chemical integrity of the configuration of substrates. Here, we revisited Schotten-Baumann condition, instead of using inorganic base. Objective: To develop green protocol for the synthesis of peptide bond using Fmoc-amino acid chloride with amino acid esters salt. Methods: The final product isolated is analyzed in several spectroscopic and analytical techniques such as FT-IR, 1H-, 13CNMR, Mass spectrometry and RP-HPLC to check stereo integrity and purity of the product. Conclusion: The present method developed greener using natural agro-waste (lemon fruit shell ash) derived solvent medium for the reaction and not required chemical entity.

β-Amino acid facilitates macrocyclic ring closure in a combinatorial library

1999 ◽  
Vol 40 (44) ◽  
pp. 7757-7760 ◽  
Author(s):  
Elizabeth A. Jefferson ◽  
Eric E. Swayze
Keyword(s):  
Amino Acid ◽  
Combinatorial Library ◽  
Ring Closure ◽  
Macrocyclic Ring

Exotic collagen gradients in the byssus of the mussel Mytilus edulis.

1995 ◽  
Vol 198 (3) ◽  
pp. 633-644 ◽  
Author(s):  
X Qin ◽  
J H Waite
Keyword(s):  
Amino Acid ◽  
Mytilus Edulis ◽  
Tandem Repeats ◽  
Inner Core ◽  
Immunogold Labelling ◽  
Outer Core ◽  
Complementary Distribution ◽  
Imino Acid ◽  
Molecular Masses ◽  
Straight Fiber

Byssal threads of the common mussel Mytilus edulis contain collagenous molecules from which two pepsin-resistant fragments have been isolated and characterized. These show a complementary distribution along the length of the thread, such that one predominates distally (Col-D) and the other proximally (Col-P). Both fragments contain three identical alpha-like chains with molecular masses of 50 kDa (Col-P) and 60 kDa (Col-D) and have typically collagenous amino acid compositions; for example, 35% glycine and almost 20% proline plus 4-trans-hydroxyproline. Hydroxylysine and 3-hydroxyproline were absent. Col-P sequences are also typical of collagen in consisting of tandem repeats of the triplet Gly-X-Y in which X and Y generally represent any amino acid. When proline occurs, it is hydroxylated to 4-trans-hydroxyproline only in the Y position. Seven instances where X is glycine have been detected in Col-P. Specific polyclonal anti-Col antibodies were used to isolate the precursors of Col-P and Col-D from the mussel foot. PreCol-P has a molecular mass of 95 kDa and contains 36% glycine but a lower imino acid content (13%). It has a complementary distribution with another precursor (preCol-D, 97 kDa) along the length of the foot. The two precursor compositions suggest resilin-like and silk-fibroin-like structures, respectively, in the noncollagenous domains of preCol-P and preCol-D. Immunogold labelling studies indicate that Col-P is associated with the coiled fibers of the inner core in the proximal portion of the thread, whereas Col-D is localized to the straight fiber bundles of the distal thread as well as to the outer core of the proximal thread.

-9-Fluorenylmethoxycarbonyl Amino Acid Chlorides

2005 ◽  
pp. 1
Author(s):  
W. D. Lubell ◽  
J. W. Blankenship ◽  
G. Fridkin ◽  
R. Kaul
Keyword(s):  
Amino Acid ◽  
Acid Chlorides

scholarly journals Concise Synthesis of Macrocycles by Multicomponent Reactions

Synthesis ◽  
2018 ◽  
Vol 50 (05) ◽  
pp. 1027-1038 ◽  
Author(s):  
Alexander Dömling ◽  
Eman Abdelraheem ◽  
Samad Khaksar
Keyword(s):  
Amino Acid ◽  
Multicomponent Reaction ◽  
Ring Opening ◽  
Multicomponent Reactions ◽  
Reaction Pathway ◽  
Ring Closure ◽  
Side Chains ◽  
Reaction Sequence ◽  
Cyclic Anhydride

A short reaction pathway was devised to synthesize a library of artificial 18–27-membered macrocycles. The five-step reaction sequence involves ring opening of a cyclic anhydride with a diamine, esterification, coupling with an amino acid isocyanide, saponification, and, finally, macro-ring closure using an Ugi or, alternatively, a Passerini multicomponent reaction. Three out of the five steps allow for the versatile introduction of linker elements, side chains, and substituents with aromatic, heteroaromatic, and aliphatic character. The versatile pathway is described for 15 different target macrocycles on a mmol scale. Artificial macrocycles have recently become of great interest due to their potential to bind to difficult post-genomic targets.

Sign in / Sign up

Export Citation Format

Share Document