- N-Terminal Selective C?H Azidation of Proline-Containing Peptides: a Platform for Late-Stage Diversification
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A methodology for the C?H azidation of N-terminal proline-containing peptides was developed employing only commercially available reagents. Peptides bearing a broad range of functionalities and containing up to 6 amino acids were selectively azidated at the carbamate-protected N-terminal residue in presence of the numerous other functional groups present on the molecules. Post-functionalizations of the obtained aminal compounds were achieved: cycloaddition reactions or C?C bond formations via a sequence of imine formation/nucleophilic addition were performed, offering an easy access to diversified peptides.
- Allouche, Emmanuelle M. D.,Simonet-Davin, Rapha?l,Waser, Jerome
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supporting information
(2022/02/25)
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- Highly Diastereoselective Synthesis of Cyclic α-Aminophosphonic and α-Aminophosphinic Acids from Glycyl-l-Proline 2,5-Diketopiperazine
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This paper describes the first diastereoselective synthesis of cyclic α-aminophosphonic and α-amino phosphonic acids from glycyl-l-proline 2,5-diketopiperazine (S)-6 prepared according to the usual peptide coupling procedures. The highlights of this contribution is the chemoselective reduction of the carbamate-imide activated carbonyl group in the N-Boc 2,5-diketopiperazine (S)-11 to generate the unstable hemiaminals (1R,8aS)-12 and (1S,8aS)-13, followed by the highly diastereoselective nucleophilic addition of trimethyl phosphite or dimethyl phenylphosphonite to the chiral carbenium ion (S)-5. Acid hydrolysis of the phosphonate and phosphinate functionalities with simultaneous cleavage of the tert-butyl carbamate protecting group led to the target compounds. The high diastereoselectivity in the nucleophilic addition of trivalent phosphorus to the chiral carbenium ion (S)-5 is in agreement with our precedent reports.
- Ordó?ez, Mario,Torres-Hernández, Fernando,Viveros-Ceballos, José Luis
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p. 7378 - 7383
(2019/11/26)
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- A bio-inspired approach to proline-derived 2,4-disubstituted oxazoles
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A convenient four-step approach to the synthesis of (S)-4-alkyl-2-(pyrrolidin-2-yl)oxazoles starting from l-Boc-proline inspired by naturally occurring oxazole-containing peptidomimetics is described. The key step is the cyclization of 1-Boc-N-(1-oxoalkan
- Slobodyanyuk, Evgeniy Y.,Artamonov, Oleksiy S.,Kulik, Irene B.,Rusanov, Eduard,Volochnyuk, Dmitriy M.,Grygorenko, Oleksandr O.
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- Total Synthesis of the Cyclic Dodecapeptides Wewakazole and Wewakazole B
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The cyclic dodecapeptides wewakazole and wewakazole B have been synthesized by a divergent strategy via a common tris-proline containing oxazole octapeptide and two separate bis-oxazole containing tetrapeptide units, followed by peptide coupling and macro
- Inman, Martyn,Dexter, Hannah L.,Moody, Christopher J.
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supporting information
p. 3454 - 3457
(2017/07/15)
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- Aggregation propensity of amyloidogenic and elastomeric dipeptides constituents
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This study demonstrates the self-assembly of N- and C-terminal protected dipeptides Phe–Gly and Pro–Gly which were derived from amyloidogenic and elastomeric peptide sequences. These constituents afforded nanostructured supramolecular ensembles through va
- Kumar, Vikas,Krishna, K. Vijaya,Khanna, Shruti,Joshi, Khashti Ballabh
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p. 5369 - 5376
(2016/08/05)
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- 9-Silafluorenyl Dichlorides as Chemically Ligating Coupling Agents and Their Application in Peptide Synthesis
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A fundamentally simple, mild, and practical procedure for peptide bond formation is reported that employs a stoichiometric amount of easy-to-access 9-silafluorenyl dichlorides as the coupling agent. Without initial preactivation or elaboration of the carboxylic acid or amine termini of the amino acids, the developed reagent is proposed to act through an unprecedented chemical ligation mechanism, bringing the two coupling partners together before being subsequently eliminated. The desired amides or peptide bonds are thus furnished in good yields and with low to no epimerization.
- Aspin, Samuel J.,Taillemaud, Sylvain,Cyr, Patrick,Charette, André B.
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supporting information
p. 13833 - 13837
(2016/10/26)
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- Nucleophilic ring-opening of benzoxazinones by DBU: Some observations
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This communication demonstrates the formation of an unusual nucleophilic ring opening of benzoxazinones by 1,8-diazabicycloundec-7-ene (DBU). This observation contradicts the intrinsic feature of a hindered nonnucleophilic base like DBU. Confirmation of t
- Baravkar, Sachin B.,Roy, Arup,Gawade, Rupesh L.,Puranik, Vedavati G.,Sanjayan, Gangadhar J.
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p. 2955 - 2960
(2014/11/07)
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- A general method for the facile synthesis of optically active 2-substituted piperazines via functionalized 2,5-diketopiperazines
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Upon utilization of some common methods described in the literature for the synthesis of chiral, 2-substituted 2,5-diketopiperazines, extensive racemization was observed. Further investigation showed that heating in the presence of a mild base racemized the chiral center in the product diketopiperazines. A generalized, readily scalable route was sought and, after investigating the effect of base and temperature, conditions were identified that promoted cyclization without erosion of enantiomeric excess. An array of functionalization was tolerated and this procedure serves as a useful and reliable method for the facile synthesis of this important class of compounds.
- Ashton, Kate S.,Denti, Mitchell,Norman, Mark H.,St. Jean Jr., David J.
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supporting information
p. 4501 - 4504
(2014/08/05)
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- Synthesis, docking and anticancer activity studies of D-proline- incorporated wainunuamide
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D-proline-incorporated wainunuamide - a cyclic octapeptide was synthesized and characterized by FTIR, 1H and 13C NMR and Mass spectral analysis. Molecular docking studies were carried out for the designed cyclic octapeptide and the results showed greater affinity for HPV18-2IOI receptor (HeLa cancer cell line). The synthesized cyclic octapeptide exhibited potent anticancer activity against HeLa cancer cells. Indian Academy of Sciences.
- Himaja,Ranjitha,Mali, Sunil V.
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p. 1049 - 1055
(2013/03/13)
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- Concurrent display of both α- and β-turns in a model peptide
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This article describes a model peptide that concurrently displays both α- and β-turns, as demonstrated by structural investigations using single crystal X-ray crystallography and solution-state NMR studies. The motif reported herein has the potential for
- Srinivas, Deekonda,Vijayadas, Kuruppanthara N.,Gonnade, Rajesh,Phalgune, Usha D.,Rajamohanan, Pattuparambil R.,Sanjayan, Gangadhar J.
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supporting information; experimental part
p. 5762 - 5765
(2011/10/02)
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- Design, synthesis, and structure-activity relationship study of bicyclic piperazine analogs of indole-3-carboxamides as novel cannabinoid CB1 receptor agonists
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Bicyclic piperazine derivatives were synthesized as conformationally constrained analogs of N-alkyl piperazines and were found to be potent CB1 receptor agonists. The CB1 receptor agonist activity was dependent upon the absolute configuration of the chiral center of the bicyclic ring system. Although the conformational constraint did not protect the compounds from metabolism by N-dealkylation, several bicyclic analogs were found to be more potent than the unconstrained lead compound. Compound 8b demonstrated potent antinociceptive activity in vivo.
- Moir, Elizabeth M.,Yoshiizumi, Kazuya,Cairns, Jim,Cowley, Phillip,Ferguson, Morag,Jeremiah, Fiona,Kiyoi, Takao,Morphy, Richard,Tierney, Jason,Wishart, Grant,York, Mark,Baker, James,Cottney, Jean E.,Houghton, Andrea K.,McPhail, Petula,Osprey, Andrew,Walker, Glenn,Adam, Julia M.
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scheme or table
p. 7327 - 7330
(2011/01/12)
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- Synthesis of a phenylalanine-rich peptide as potential anthelmintic and cytotoxic agent
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A natural cyclic heptapeptide segetalin D [VIII] was synthesized by coupling of tripeptide unit Boc-Pro-Gly-Leu-OMe [V] with tetrapeptide unit Boc-Ser-Phe-Ala-Phe-OMe [VI] after proper deprotection at carboxyl and amino ends followed by cyclization of linear peptide segment. Structure of VIII was confirmed by spectral and elemental analyses. The newly synthesized cyclopeptide was tested for its antibacterial, antifungal, anthelmintic and cytotoxic activities. Compound VIII showed high cytotoxicity against Dalton's lymphoma ascites (DLA) and Ehrlichis ascites carcinoma (EAC) cell lines with CTC50 values of 7.54 and 13.56 μM. Moreover, VIII exhibited potent anthelmintic activity against earthworms Eudrilus species, Megascoplex konkanensis and Pontoscotex corethruses at a dose of 2 mg/mL.
- Dahiya, Rajiv
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p. 509 - 516
(2008/12/22)
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- Ring-closing alkyne metathesis approach toward the synthesis of alkyne mimics of thioether A-, B-, C-, and DE-ring systems of the lantibiotic nisin Z
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(Chemical Equation Presented) Ring-closing alkyne metathesis toward the synthesis of the alkyne-brigded A-, B-, C-, and (D)E-ring mimics of the peptide antibiotic nisin Z is described. We have successfully synthesized alkyne-bridged cyclic peptides containing 4-7 amino acid residues in yields ranging from 18 to 82%.
- Ghalit, Nourdin,Poot, Alex J.,Fuerstner, Alois,Rijkers, Dirk T. S.,Liskamp, Rob M. J.
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p. 2961 - 2964
(2007/10/03)
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- A rapid and efficient synthesis of β-casomorphin employing Boc-amino acids and 9-fluorenylmethyl chloroformate as a coupling agent
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The synthesis of β-casomorphin H-Tyr-Pro-Phe-Pro-Gly-OH employing Boc group for Nα-protection and 9-fluorenylmethyl chloroformate (Fmoc-Cl) for the formation of peptide bond is described. The protocol employing Fmoc-Cl as coupling reagent is found to be simple, efficient and rapid. All the intermediate peptides as well as the final protected peptide Boc-Tyr( iBu)-Pro-Phe-Pro-Gly-OMe have been isolated and fully characterized. They have been obtained in good yield and with high purity.
- Babu, V.V. Suresh,Tantry
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p. 2708 - 2712
(2007/10/03)
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- [Bis(2-methoxyethyl)amino]sulfur Trifluoride, the Deoxo-Fluor Reagent: Application toward One-Flask Transformations of Carboxylic Acids to Amides
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The use of the Deoxo-Fluor reagent is a versatile method for acyl fluoride generation and subsequent one-flask amide coupling. It provides mild conditions and facile purification of the desired products in good to excellent yields. We have explored the utility of this reagent for the one-flask conversion of acids to amides and Weinreb amides and as a peptide-coupling reagent.
- White, Jonathan M.,Tunoori, Ashok Rao,Turunen, Brandon J.,Georg, Gunda I.
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p. 2573 - 2576
(2007/10/03)
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- SUBSTITUTED HEXAHYDROPYRROLO[1,2-A]PYRAZINES, OCTAHYDROPYRIDO[1,2-A]-PYRAZINES AND DECAHYDROPYRAZINO[1,2-A]AZEPINES
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Novel substituted hexahydropyrrolo[1,2-a]pyrazines, octahydropyrido[1 , 2-a]-pyrazines and decahydropyrazino[1,2-a]azepines, use of these compounds as pharmaceutical compositions, pharmaceutical compositions comprising the compounds, and a method of treatment employing these compounds and compositions. The compounds show a high and selective binding affinity to the histamine H3 receptor indicating histamine H3 receptor antagonistic, inverse agonistic or agonistic activity. As a result, the compounds are useful for the treatment of diseases and disorders related to the histamine H3 receptor.
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Page/Page column 10
(2010/02/05)
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- SUBSTITUTED HEXAHYDROPYRROLO[1,2-A]PYRAZINES, OCTAHYDROPYRIDO[1,2-A]PYRAZINES AND DECAHYDROPYRAZINO[1,2-A]AZEPINES
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Novel substituted hexahydropyrrolo[1,2-a]pyrazines, octahydropyrido[1,2-a]-pyrazines and decahydropyrazino[1,2-a]azepines, use of these compounds as pharmaceutical compositions, pharmaceutical compositions comprising the compounds, and a method of treatment employing these compounds and compositions. The compounds show a high and selective binding affinity to the histamine H3 receptor indicating histamine H3 receptor antagonistic, inverse agonistic activity. As a result, the compounds are useful for the treatment of diseases and disorders related to the histamine H3 receptor.
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- Coupling in the absence of a tertiary base: A method for the deprotonation of hydrochloride salts of peptide esters to free amino peptide esters
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The deprotonation of hydrochloride salts of peptide esters is accomplished using activated zinc dust. The reaction is neat and quantitative. Addition of a tertiary base is eliminated during the coupling. The free amino peptide esters have been isolated in good yield and purity. This method is extended for the synthesis of β-casomorphin (Tyr-Pro-Phe-Pro-Gly). During its synthesis, all the intermediate free amino peptide esters have been isolated and characterized.
- Tantry, Subramanyam J.,Ananda,Suresh Babu
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p. 1028 - 1031
(2007/10/03)
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- Electrogenerated chiral cationic glycine equivalents - Part 1: The 6-methoxy derivative of cyclo(L-Pro-Gly)
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The cyclic N,O-acetal cyclo(L-Pro-Gly(OMe)OMe (8) has proved to be an effective chiral electrophilic glycine equivalent which is applicable in nucleophilic substitution reactions not only under Broenstedt acid catalysis but also under Lewis acid catalysis with excellent diastereoselectivities. This chiral building block can easily be obtained by electrochemical methoxylative decarboxylation of the cyclic dipeptide 6 generated from L-proline and aminomalonic diester. Thus, enantiomerically pure D-allyl glycine has been generated.
- Kardassis, Georgios,Brungs, Peter,Steckhan, Eberhard
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p. 3471 - 3478
(2007/10/03)
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- Electrogenerated chiral building blocks for diastereoselective amidoalkylation reactions
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Three different electrochemical methods have been applied for the synthesis of chiral building blocks for diastereoselective amidoalkylation reactions. These are A. the direct anodic α-methoxylation of amides and carbamates; B. anodic methoxylative decarboxylation of α-amino acid derivatives (Hofer-Moest reaction) C. indirect NaCl mediated anodic α-methoxylation of α-amino acid derivatives. The application of these building blocks for the synthesis of enantiomerically pure α-amino acids, dichiral 1,2-amino alcohols and chiral 1,3-diamines is described.
- Brungs,Danielmeier,Jakobi,Nothhelfer,Stahl,Zietlow,Steckhan
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p. 575 - 590
(2007/10/03)
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