33294-54-1Relevant academic research and scientific papers
Induced axial chirality in the biphenyl core of the proatropoisomeric, Cα-tetrasubstituted α-amino acid residue Bip in peptides
Mazaleyrat, Jean-Paul,Wright, Karen,Gaucher, Anne,Toulemonde, Nathalie,Dutot, Laurence,Wakselman, Michel,Broxterman, Quirinus B.,Kaptein, Bernard,Oancea, Simona,Peggion, Cristina,Crisma, Marco,Formaggio, Fernando,Toniolo, Claudio
, p. 6921 - 6929 (2005)
An induced axial chirality in the biphenyl core of the 2′,1′:1,2;1″,2″:3,4-dibenzcyclohepta-1, 3-diene-6-amino-6-carboxylic acid (Bip) residue, a conformationally labile, atropoisomeric, Cα-tetrasubstituted α-amino acid, was observed by CD and 1H NMR spectroscopic techniques in the linear dipeptides Boc-Bip-Xaa*-OMe where Boc = tert-butoxycarbonyl, OMe = methoxy, and Xaa* = D- and/or L-Ala, -Val, -Leu, -Phe, -(αMe)Val and -(αMe)Leu. Chiral induction was significantly lower in the isomeric dipeptides Boc-Xaa*-Bip-OMe, with the Xaa* residue located at the N-terminus of Bip, as well as in the cyclic dipeptide cyclo-[Bip-L-Ala]. The results obtained in solution were confirmed by X-ray diffraction analysis of a crystalline sample of Boc-(R)-Bip-D-Ala-OMe.
Electrophilic Activation of Carboxylic Anhydrides for Nucleophilic Acylation Reactions
Kumar, Varun,Kumar, Yashwant,Lal Meena, Chhuttan,Mahajan, Dinesh,Rana, Anil,Sharma, Nidhi
, p. 3902 - 3910 (2018/09/29)
Nucleophilic acylation of symmetrical carboxylic anhydrides has inherited limitation of reaction efficiency along with relatively poor reactivity. Traditionally, one equivalent carboxylic acid is generated during nucleophilic acylation of a symmetrical anhydride, which always limits the yield of final product to 50percent or less. This is a major drawback, which discourages the use of anhydrides for laboratory or industrial applications. Electrophilic activation of carboxylic anhydride using methanesulfonyl chloride is found to be an efficient method for nucleophilic acylation, which increases product yield by restricting the formation of corresponding acid as a side product. The developed protocol found to be a mild and high yielding methodology for one-pot nucleophilic acylation of carboxylic anhydrides with several type of N- and S-nucleophiles demonstrating appreciable functional group tolerance.
Synthesis of 6- and 7-membered cyclic enaminones: Scope and mechanism
Niphakis, Micah J.,Turunen, Brandon J.,Georg, Gunda I.
supporting information; experimental part, p. 6793 - 6805 (2010/12/20)
Six- and seven-membered cyclic enaminones can be prepared using common, environmentally benign reagents. Amino acids are used as synthetic precursors allowing diversification and the incorporation of chirality. The key reaction in this multistep process involves deprotection of Boc-amino ynones and subsequent treatment with methanolic K2CO3 to induce cyclization. A β-amino elimination side reaction was identified in a few labile substrates that led to either loss of stereochemical purity or degradation. This process can be mitigated in specific cases using mild deprotection conditions. NMR and deuterium-labeling experiments provided valuable insight into the workings and limitations of this reaction. Although disguised as a 6-endo-dig cyclization, the reagents employed in the transformation play a direct role in bond-making and bond-breaking, thus changing the mode of addition to a 6-endo-trig cyclization. This method can be used to construct an array of monocyclic and bicyclic scaffolds, many of which are found in well-known natural products (e.g., indolizidine, quinolizidine, and Stemona alkaloids).
Synthesis of amino-acid derivatives of chrysin
Veselovskaya,Garazd,Ogorodniichuk,Garazd,Khilya
experimental part, p. 704 - 711 (2009/04/10)
Various conjugates of amino acids with chrysin in which the amino acid was bonded through the C- or N-terminus to the flavone were prepared using peptide chemistry methods (symmetric anhydrides and activated esters).
Aziridinyl peptides as inhibitors of cysteine proteases: Effect of a free carboxylic acid function on inhibition
Schirmeister,Peric
, p. 1281 - 1291 (2007/10/03)
Peptides containing aziridine-2,3-dicarboxylate (Azi) as electrophilic building block are evaluated as inhibitors of the cysteine proteases papain, cathepsin B, cathepsin L and clostripain. The influence of a free carboxylic acid as functional group at di
Design, synthesis, and evaluation of Phe-Gly mimetics: Heterocyclic building blocks for pseudopeptides
Borg, Susanna,Vollinga, Roeland C.,Labarre, Maryse,Payza, Kemal,Terenius, Lars,Luthman, Kristina
, p. 4331 - 4342 (2007/10/03)
Enantiopure heterocyclic Boc-protected Phe-Gly dipeptidomimetics containing 1,3,4-oxadiazole, 1,2,4-oxadiazole, and 1,2,4-triazole ring systems have been synthesized as building blocks in the synthesis of pseudopeptides. Three derivatives (1-3) have the c
Synthesis of 1,2,4-Oxadiazole-, 1,3,4-Oxadiazole-, and 1,2,4-Triazole-Derived Dipeptidomimetics
Borg, Susanna,Estenne-Bouhtou, Genevieve,Luthman, Kristina,Csoeregh, Ingeborg,Hesselink, Willy,Hacksell, Uli
, p. 3112 - 3120 (2007/10/02)
Three series of heterocyclic dipeptidomimetics have been synthesized.The compounds were designed as amino acid-glycine mimetics containing 1,2,4-oxadiazole, 1,3,4-oxadiazole, and 1,2,4-triazole ring systems, useful as building blocks in the synthesis of m
'Glycylcyclines'. 3. 9-Aminodoxycyclinecarboxamides
Barden,Buckwalter,Testa,Petersen,Lee
, p. 3205 - 3211 (2007/10/02)
A series of 9-(acylamino)doxycycline derivatives has been prepared. These analogs exhibit good activity against both tetracycline sensitive and tetracycline resistant Gram-positive (Staphylococcus aureus) and Gram- negative (Escherichia coli) bacteria tha
PHASE MANAGED ORGANIC SYNTHESIS 3. SYMMETRICAL ANHYDRIDES FROM CARBOXYLIC ACIDS VIA POLYMER ASSISTED REACTION.
Fife, Wilmer K.,Zhang, Zhi-dong
, p. 4937 - 4940 (2007/10/02)
Symmetrical anhydrides are produced quickly and in high yield by treating mixtures of a carboxylic acid and one-half equivalent thionyl chloride in dichloromethane with a solid-state copolymer of 4-vinylpyridine.This conversion is accomplished equally well in batch or column mode.
Synthesis of Pyridine Derivatives of L-Phenylalanine as Antisickling Reagents
Altman, Janina,Gorecki, Marian,Wilchek, Meir,Votano, Joseph R.,Rich, Alexander
, p. 596 - 600 (2007/10/02)
Several bicyclic agents composed of L-phenylalanine coupled to various pyridines were synthesized: 2-, 3-, and 4-(L-phenylalanylamino)pyridine.All three compounds at 3 mM gave positive morphological antisickling effects on homozygous SS cells under reduce
