- Facile synthesis of optically active imidazole derivatives
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Five optically active imidazole derivatives have been synthesized via a facile 4-step reaction sequence starting from commercially available and inexpensive N-Cbz amino acids. While microwave assisted condensation was unsuccessful, the condensation of the
- Marek, Ales,Kulhanek, Jiri,Ludwig, Miroslav,Bures, Filip
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- Investigation of permeation of theophylline through skin using selected piperazine-2,5-diones
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Transdermal administration of drugs that penetrate, in this case directly into the blood circulation, has many advantages and is promising for many drugs thanks to its easy application and good patient compliance. (S)-8-Methyl-6,9-diazaspiro[4.5]decan-7,10-dione (alaptide), has been studied as a potential chemical permeation enhancer. Based on its structure, four selected piperazine-2,5-diones were synthesized by means of multi-step synthetic pathways. All the compounds were investigated on their ability to enhance the permeation of the model drug theophylline from the hydrophilic medium propylene glycol:water (1:1). In vitro experiments were performed using vertical Franz diffusion cells at constant temperature 34 ± 0.5 ?C and using full-thickness pig (Sus scrofa f. domestica) ear skin. Withdrawn samples were analyzed by RP-HPLC for determination of the permeated amount of theophylline. All the compounds were applied in ratio 1:10 (w/w) relative to the amount of theophylline. One hour after application, the permeated amount of theophylline from formulations with alaptide and (3S,6S)-3,6-dimethylpiperazine-2,5-dione, was ca. 15- and 12-fold higher, respectively, than from the formulation without the tested compounds. Despite the enhancement ratio of both enhancers in a steady state was ca. 2.3, the pseudo-enhancement ratio in the time range from 1 to 3 h was 4.4. These enhancement ratios indicate that the compounds are able to enhance the permeation of agents through the skin; however, the short-term application of both compound formulations seems to be more advantageous. In addition, the screening of the cytotoxicity of all the prepared compounds was performed using three cell lines, and the compounds did not show any significant toxic effect.
- Pokorna, Aneta,Bobal, Pavel,Oravec, Michal,Rarova, Lucie,Bobalova, Janette,Jampilek, Josef
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- Synthesis of Acetaminophen Analogues Containing α-Amino Acids and Fatty Acids for Inhibiting Hepatotoxicity
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Acetaminophen is a popular antipyretic analgesic medicine that has weaker anti-inflammatory properties and lower incidence of side effects than nonsteroidal anti-inflammatory drugs (NSAIDs). However, acetaminophen causes hepatotoxicity due to the reactive metabolite N -acetyl- p -benzoquinone imine (NAPQI). We have obtained acetaminophen analogues in 57-99percent yields by using aniline derivatives with protected α-amino acids and fatty acids via the corresponding mixed carbonic carboxylic anhydrides in aqueous MeCN. We have also succeeded in synthesizing AM404 analogues in 76-97percent yields, which are expected to be promising candidates for reducing hepatotoxicity.
- Imai, Nobuyuki,Jung, Seunghee,Kawashima, Yuya,Noguchi, Takuya
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p. 3686 - 3696
(2019/09/30)
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- Ecological base-conditioned preparation of dipeptides using unprotected α-amino acids containing hydrophilic side chains
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The coupling reactions of 3-phenylpropanoic acid and Ncarboxybenzyl á-amino acids with unprotected á-amino acids containing hydrophilic side chains such as aliphatic alcohol, aromatic alcohol, thiol, carboxylic acid, and amide afforded the corresponding amides in 6696% yield without racemization via the corresponding mixed carbonic carboxylic anhydrides under basic conditions through an ecological green synthetic method.
- Ezawa, Tetsuya,Jung, Seunghee,Kawashima, Yuya,Noguchi, Takuya,Imai, Nobuyuki
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p. 689 - 696
(2017/07/22)
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- Double axial chirality promoted asymmetric [2,3] Stevens rearrangement of N-cinnamyl l-alanine amide-derived ammonium ylides
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The base-induced asymmetric [2,3] Stevens rearrangement of N-cinnamyl tetraalkylammonium ylides derived from l-alanine amides proceeds via a double axially chiral intermediate to afford the corresponding α-substituted alanine derivatives with high enantio- and diastereoselectivities. the Partner Organisations 2014.
- Tayama, Eiji,Naganuma, Noriko,Iwamoto, Hajime,Hasegawa, Eietsu
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supporting information
p. 6860 - 6862
(2014/06/23)
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- Synthesis of Nα-Z protected amino alkyl triazole acids and their application to neo-glycopeptides synthesis
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The synthesis of triazole linked glycopeptides employing 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) mediated coupling of Z-protected triazole acids with glycosyl amines and amino acid esters is described. The coupling proceeded smoothly at room temperat
- Madhu, Chilakapati,Panguluri, Nageswara Rao,Sureshbabu, Vommina V.
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p. 858 - 864
(2014/08/05)
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- Continuous flow synthesis of β-amino acids from α-amino acids via Arndt-Eistert homologation
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A fully continuous four step process for the preparation of β-amino acids from their corresponding α-amino acids utilizing the Arndt-Eistert homologation approach is described. the Partner Organisations 2014.
- Pinho, Vagner D.,Gutmann, Bernhard,Kappe, C. Oliver
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p. 37419 - 37422
(2014/12/09)
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- Synthesis of enantiopure free and N-benzyloxycarbonyl-protected 3-substituted homotaurines from naturally occurring amino acids
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Enantiopure N-benzyloxycarbonyl-protected and free 3-substituted homotaurines were synthesized from naturally occurring amino acids via N-benzyloxycarbonyl protection, Arndt-Eistert homologation, reduction, esterification with thioacetic acid, and oxidation with performic acid. The current method is a convenient, practical, and salt-free method for the synthesis of enantiopure 3-substituted homotaurine with moderate to good yields.
- Zheng, Yongpeng,Xu, Jiaxi
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p. 5197 - 5206
(2014/12/10)
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- One-pot synthesis of orthogonally protected dipeptide selenazoles employing Nα-amino selenocarboxamides and α-bromomethyl ketones
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A simple and efficient protocol for the synthesis of selenazole containing dipeptidomimetics using Nα-amino selenocarboxamides and α-bromomethyl ketones is described. All the compounds made were isolated in good yields and fully characterized.
- Madhu, Chilakapati,Panguluri, Nageswara Rao,Narendra,Panduranga,Sureshbabu, Vommina V.
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supporting information
p. 6831 - 6835
(2015/01/09)
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- A mild multistep conversion of n-protected α-amino acids into N-protected β3-amino acids utilizing the Nef reaction
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Current methods of homologation of α-amino acids to β-amino acids have limitations. To overcome these shortfalls the Nef reaction has been utilized in the multistep synthesis of β3-amino acids from α-amino acids. In this approach, N-protected a
- Sleebs, Brad E.,Nguyen, Nghi H.,Hughes, Andrew B.
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supporting information
p. 747 - 751
(2013/05/08)
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- Convenient preparation of primary amides via activation of carboxylic acids with ethyl chloroformate and triethylamine under mild conditions
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Primary amides were easily prepared in 22-99% yields from the corresponding carboxylic acids 1 or 5 with NH4Cl via activation with ClCO 2Et and Et3N. The enantiomers of the corresponding primary amides of Cbz-, Boc-, or Fmoc-α-amino acids can be separated by using a chiral column.
- Noguchi, Takuya,Sekine, Masahiro,Yokoo, Yuki,Jung, Seunghee,Imai, Nobuyuki
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p. 580 - 582
(2013/07/05)
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- Convenient synthesis of acetaminophen analogues containing α-amino acids and fatty acids via their mixed carbonic carboxylic anhydrides in aqueous organic solvent
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Acetaminophen analogues containing α-amino acid and fatty acids were easily synthesized in 77-99% yields from the corresponding mixed carbonic carboxylic anhydrides of α-amino acid and fatty acids using aniline derivatives in aqueous MeCN.
- Jung, Seunghee,Tsukuda, Yuki,Kawashima, Rie,Ishiki, Takumi,Matsumoto, Ayaka,Nakaniwa, Aya,Takagi, Miho,Noguchi, Takuya,Imai, Nobuyuki
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p. 5718 - 5720
(2013/09/24)
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- Synthesis of a new class of bis(thiourea)hydrazide pseudopeptides as potential inhibitors of β-sheet aggregation
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The modular synthesis of a novel pseudopeptide scaffold based on a bis(thiourea)hydrazide motif is reported. This compound class is designed to display "amphifinity", i.e. association with a peptide strand on one but not the other face of the scaffold, and hence could potentially inhibit β-sheet aggregation.
- Klein, Jan J.,Hecht, Stefan
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supporting information; experimental part
p. 330 - 333
(2012/02/04)
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- Direct synthesis of phosphinopeptides containing C-terminal α-aminoalkylphosphinic acids
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A series of phosphinopeptides containing C-terminal α- aminoalkylphosphinic acids were prepared in good yields directly in one-pot reactions of 2-(N-benzoxycarbonylamino)alkanamides/peptide amides, aldehydes, and aryldichlorophosphines, followed by hydrolysis. In the current method, the peptide bond was formed in a Mannichtype reaction. Springer-Verlag 2010.
- Meng, Fanhua,Xu, Jiaxi
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experimental part
p. 533 - 538
(2010/11/04)
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- Peptidomimetics through click chemistry: Synthesis of novel β-Keto triazole acids from N-protected amino acids
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An efficient procedure for the preparation of azidomethylketones from N-urethane protected amino acids and their application in Cu(I) catalyzed azide-alkyne cycloaddition reaction are described. The synthesis has been carried out under mild conditions wit
- Narendra,Vishwanatha,Sureshbabu, Vommina V.
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experimental part
p. 283 - 290
(2011/10/04)
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- Syntheses of peptidoglycolipid analogs with distinct immunomodulating activities
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Amphiphilic 2-amino-2-deoxy-β-D-glucopyranosylamides were synthesized from N-protected glucosamine derivatives via N-glycosidation with fatty amines, subsequent N-acylation with fatty acid derivatives and deprotection. They could further be modified with
- Lockhoff, Oswald,Hayauchi, Yutaka
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p. 603 - 619
(2007/10/03)
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- Synthesis of functionalised oxazoles and bis-oxazoles
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A new method for the synthesis of oxazoles, and in particular chiral non-racemic oxazoles derived from amino acids, has been developed. Thus, rhodium(II) catalysed reaction of diazocarbonyl compounds 6 and 11 in the presence of amides 8 and 10 results in regioselective insertion of the carbenoid into the amide N-H bond with formation of the β-carbonyl amides 9 and 12. Cyclodehydration of amides 9 and 12 using triphenylphosphine-iodine-triethylamine gives functionalised oxazoles 7 and 13. The oxazoles 13c and 13f were converted into the bis-oxazoles 17a and 17b by a second rhodium(II) catalysed regioselective N-H insertion reaction on the amides 15, followed by cyclodehydration.
- Bagley, Mark C.,Buck, Richard T.,Hind, S. Lucy,Moody, Christopher J.
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p. 591 - 600
(2007/10/03)
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- Die Arndt-Eistert-Reaktion in der Peptidchemie: ein einfacher Zugang zu Homopeptiden
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Stichworte: Arndt-Eistert-Reaktionen. β-Aminosaeuren.Dihydrooxazinone.Homopeptide.Peptid-Analoga
- Podlech, Joachim,Seebach, Dieter
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p. 507 - 509
(2007/10/02)
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- On the Preparation of β-Amino Acids from α-Amino Acids Using the Arndt-Eistert Reaction: Scope, Limitations and Stereoselectivity. Application to Carbohydrate Peptidation. Stereoselective α-Alkylations of Some β-Amino Acids
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The Arndt-Eistert homologation of α-amino acids was studied to determine the stereoselectivity in this reaction by chromatographic up-to-date analytical methods.While carbamate-protected phenylglycine was transformed to the corresponding β-amino acid methyl ester with a stereoselectivity of only 9:1, all other tested amino acid derivatives (Ala, Phe, Ser, Orn, tert-Leu and perhydro-azepine-2-carboxylic acid, suitably protected) were homologated with full retention of configuration (products 9-17).The intermediate diazo ketones 1-8 were purified and characterized by their NMR spectra.When nucleophiles derived from partially protected sugars were present during decomposition of the diazo ketones (derived from amino acids or dipeptides), a strong dependence of the yield (products 21-24) on the degree of steric hindrance of the nucleophilic OH group was observed.Two of the β-amino acids obtained from the homologation reaction were transformed to α-substituted (25-27, 31, 32) and α,α-disubstituted β-amino acid derivatives (28, 29) with excellent selctivities (in most cases, a single diastereoisomer was obtained). - Key Words: β-Amino acids, α-branched/Glycopeptides
- Podlech, Joachim,Seebach, Dieter
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p. 1217 - 1228
(2007/10/02)
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- Synthetic Analogues of Naturally Occurring Spider Toxins
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Naturally occurring spider toxins are potent inhibitors of glutamate receptors of the central nervous system and have the general structure (hetero)arylacyl->aminoacyl(I)-polyamine-aminoacyl(II) (the arrow indicates the direction of an amide linkage).In
- Kovacs, Lajos,Hesse, Manfred
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p. 1909 - 1924
(2007/10/02)
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- Preparation of N-acylated phosphonopeptides with free phosphonic group
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Aminoalkylphosphonic acids on heating with hexamethyldisilazane yield tris(trimethylsilyl) derivatives, which are used as amino components for the synthesis of N-acylated phosphonopeptides with free phosphonic group. These transformations proceed with complete retention of the stereoconfiguration of aminophosphonate moiety.
- Solodenko,Kasheva,Kukhar
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p. 1631 - 1641
(2007/10/02)
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- A Convenient One-Pot Conversion of N-Protected Amino Acids and Peptides into Alcohols
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N-Protected amino acids and peptides are converted to alcohols by chemoselective reduction of their corresponding mixed anhydrides with sodium borohydride in tetrahydrofuran with dropwise addition of methanol.
- Kokotos, George
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p. 299 - 301
(2007/10/02)
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- Synthesis of O-Glycopeptides of the N-Terminus of Interleukin-2
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The synthesis of a number of O-glycopeptides with different lengths of chain of between 3 and 10 amino acids that are part of the N-terminus of interleukin-2 is described.The key intermediate for the syntheses is O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-α-D-galactopyranosyl)-N-(9-fluorenylmethoxycarbonyl)-L-threonine tert-butyl ester (9b), to which suitably protected amino acids and peptides can be added C- or N-terminally. 9b is an element, which allows to insert glycosylated hydroxyamino acids with the Fmoc/tBu combination of protective groups, which are approved in peptide synthesis.During the syntheses peptide blocks are used.With the deprotected products it is possible to test the structural specificity of glycosyl transferases.
- Paulsen, Hans,Adermann, Knut
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p. 751 - 770
(2007/10/02)
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- Antibacterial Activity of Phosphono Dipeptides Related to Alafosfalin
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A series of dipeptides containing N-terminal alanine or leucine and a wide range of P-terminal racemic 1-aminoalkanephosphonates were prepared and tested in vitro for their ability to inhibit the growth of various bacterial species. The results demonstrat
- Lejczak, Barbara,Kafarski, Pawel,Sztajer, Helena,Mastalerz, Przemyslaw
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p. 2212 - 2217
(2007/10/02)
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- SYNTHESIS OF PEPTIDES, GLYCO DERIVATIVES AND GLYCOPEPTIDES FROM BACTERIAL CELL WALLS
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Synthesis in solution and in solid phase was used to prepare alanyl-D-isoglutamine (VI), alanyl-D-isoglutaminyl-Nε-p-toluenesulfonyl-lysyl-D-alanine methyl ester (XIII), alanyl-D-isoglutaminyl-Nε-acetyl-lysyl-D-alanine methyl ester (XIV), alanyl-D-isoglutaminyl-Nε-acetyl-lysyl-D-alanyl-pentaglycine methyl ester and amide (XXXI, XXXII), methyl ester (XXXV), methyl ester (XXXVII), N-acetylmuramyl-alanyl-D-isoglutaminyl-Nε-acetyl-lysyl-D-alanyl-pentaglycine amide (XXXIX), methyl ester (XLI), and methyl ester (XLIII).Thetetrapeptides, nonapeptides, and tridecapeptides show a pronounced pyrogenic effect.Imunoadjuvant activity was observed not only with the glycopeptides but also with nonapeptide XXXI.
- Zaoral, Milan,Jezek, Jan,Krchnak, Viktor,Straka, Radovan
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p. 1424 - 1446
(2007/10/02)
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