28094-25-9Relevant academic research and scientific papers
Synthesis of enantiopure free and N-benzyloxycarbonyl-protected 3-substituted homotaurines from naturally occurring amino acids
Zheng, Yongpeng,Xu, Jiaxi
, p. 5197 - 5206 (2014/12/10)
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.
Synthesis of enantiopure free and N-benzyloxycarbonyl-protected 3-substituted homotaurines from naturally occurring amino acids
Zheng, Yongpeng,Xu, Jiaxi
, p. 5197 - 5206 (2014/07/08)
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.
Design and synthesis of potent Quillaja saponin vaccine adjuvants
Adams, Michelle M.,Damani, Payal,Perl, Nicholas R.,Won, Annie,Hong, Feng,Livingston, Philip O.,Ragupathi, Govind,Gin, David Y.
supporting information; experimental part, p. 1939 - 1945 (2010/05/11)
The success of antitumor and antiviral vaccines often requires the use of an adjuvant, a substance that significantly enhances the immune response to a coadministered antigen. Only a handful of adjuvants have both sufficient potency and acceptable toxicity for clinical investigation. One promising adjuvant is QS-21, a saponin natural product that is the immunopotentiator of choice in many cancer and infectious disease vaccine clinical trials. However, the therapeutic promise of QS-21 adjuvant is curtailed by several factors, including its scarcity, difficulty in purification to homogeneity, dose-limiting toxicity, and chemical instability. Here, we report the design, synthesis, and evaluation of chemically stable synthetic saponins. These novel, amide-modified, non-natural substances exhibit immunopotentiating effects in vivo that rival or exceed that of QS-21 in evaluations with the GD3-KLH melanoma conjugate vaccine. The highly convergent synthetic preparation of these novel saponins establishes new avenues for discovering improved molecular adjuvants for specifically tailored vaccine therapies.
Facile synthesis of optically active imidazole derivatives
Marek, Ales,Kulhanek, Jiri,Ludwig, Miroslav,Bures, Filip
, p. 1183 - 1190 (2008/02/07)
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
Effective methods for the synthesis of N-methyl β-amino acids from all twenty common α-amino acids using 1,3-oxazolidin-5-ones and 1,3-oxazinan-6-ones
Hughes, Andrew B.,Sleebs, Brad E.
, p. 2611 - 2637 (2007/10/03)
N-Methyl β-amino acids are generally required for application in the synthesis of potentially bioactive modified peptides and other oligomers. Previous work highlighted the reductive cleavage of 1,3-oxazolidin-5-ones to synthesise N-methyl α-amino acids. Starting from α-amino acids, two approaches were used to prepare the corresponding N-methyl β-amino acids. First, α-amino acids were converted to N-methyl α-amino acids by the so-called '1,3-oxazolidin-5-one strategy', and these were then homologated by the Arndt-Eistert procedure to afford N-protected N-methyl β-amino acids derived from the 20 common α-amino acids. These compounds were prepared in yields of 23-57% (relative to N-methyl α-amino acid). In a second approach, twelve N-protected α-amino acids could be directly homologated by the Arndt-Eistert procedure, and the resulting β-amino acids were converted to the 1,3-oxazinan-6-ones in 30-45% yield. Finally, reductive cleavage afforded the desired N-methyl β-amino acids in 41-63% yield. One sterically congested β-amino acid, 3-methyl-3-aminobutanoic acid, did give a high yield (95%) of the 1,3-oxazinan-6-one (65), and subsequent reductive cleavage gave the corresponding AIBN-derived N-methyl β-amino acid 61 in 71% yield (Scheme 2). Thus, our protocols allow the ready preparation of all N-methyl β-amino acids derived from the 20 proteinogenic α-amino acids.
Chiral imidazole derivatives synthesis from enantiopure N-protected α-amino acids
Bures, Filip,Kulhanek, Jiri
, p. 1347 - 1354 (2007/10/03)
A route to the preparation of enantiopure ligands based on a 2-phenylimidazol ring is described. The stereogenic centre is placed into the chain bonded to the fourth carbon of the imidazole ring. The synthesis starts from inexpensive and readily available
Enantiopure N-protected α-amino glyoxals 1. Synthesis from α-amino acids and some condensation reactions with amines
Darkins, Paul,Groarke, Michelle,McKervey, M. Anthony,Moncrieff, Hazel M.,McCarthy, Noreen,Nieuwenhuyzen, Mark
, p. 381 - 389 (2007/10/03)
A series of N-protected α-ammo diazoketones has been prepared from L-amino acids and dipeptides and used as precursors in the synthesis of novel N-protected α-amino glyoxals via oxidation with distilled dimethyldioxirane (DMD) in acetone. The glyoxals have been converted, without purification, into enantiopure imines, pyrazines, quinoxalines, and pyrido[2,3-b]pyrazines via condensation with the appropriate amine or diamine. The molecular structure of the pyrido[2,3-b]pyrazine derived from N-Cbz-L-phenylalanine has been determined by X-ray analysis.
SYNTHESIS OF DIAZOKETONES DERIVED FROM α-AMINO ACIDS; PROBLEM OF SIDE REACTIONS
Plucinska, Krystyna,Liberek, Bogdan
, p. 3509 - 3518 (2007/10/02)
Optimum conditions of synthesis of eight diazoketones derived from optically active N-(t-butyloxycarbonyl)- and N-benzyloxycarbonylamino acids have been described.The problem of formation of by-products during Arndt-Eistert synthesis of β-homoamino acids at the stage of reaction of mixed anhydride with a weak nucleophile-diazomethane - has been discussed.
