5429-56-1Relevant articles and documents
Boron Accumulation in Brain Tumor Cells through Boc-Protected Tryptophan as a Carrier for Boron Neutron Capture Therapy
Chio, Chun-Ming,Chou, You-Cheng,Hsu, Fu-Chun,Huang, Ying-Cheng,Lai, Yen-Buo,Yu, Chung-Shan
supporting information, p. 589 - 596 (2020/04/30)
Boron neutron capture therapy (BNCT) is a binary therapeutic approach. Nonradioactive boron-10 atoms accumulated in tumor cells combining with the neutron beams produce two highly energetic particles that could eradicate the cell that takes it and the neighboring cells. Small molecules that carry boron atom, e.g. 5- and 6-boronated and 2,7-diboronated tryptophans, were assessed for their boron accumulation in U87-MG, LN229, and 3T3 for BNCT. TriBoc tryptophan, TB-6-BT, shows boron-10 at 300 ppm in both types of tumor cells with a tumor to normal ratio (T/N) of 5.19-5.25 (4 h). TB-5-BT and DBA-5-BT show boron-10 at 300 ppm (2 h) in U87-MG cells. TB-5-BT exerts a T/N of >9.66 (1 h) in LN229 compared with the current clinical boronophenyl alanine with a highest T/N of 2.3 (1 h) and accumulation concentration of 50 ppm. TB-5-BT and TB-6-BT warrant further animal study.
Tailored Approaches towards the Synthesis of l-S-(Trifluoromethyl)cysteine- and l-Trifluoromethionine-Containing Peptides
Gadais, Charlène,Saraiva-Rosa, Nathalie,Chelain, Evelyne,Pytkowicz, Julien,Brigaud, Thierry
supporting information, p. 246 - 251 (2017/01/24)
Among the fluorinated noncanonical amino acids, l-trifluoromethionine (TFM) and l-S-(trifluoromethyl)cysteine (TfmCys), fluorinated analogues of methionine and cysteine, are of particular interest because of their ability to locally increase the hydrophobicity of peptides. We report herein the synthesis of tert-butoxycarbonyl/benzyl-protected TFM and TfmCys by using a cheap and user-friendly radical trifluoromethylation approach. The benzyl protecting group of these fluorinated amino acids could be conveniently removed by hydrogenolysis, which circumvented troublesome saponification reactions. For the first time, TfmCys was inserted into a peptide sequence by liquid- or solid-phase peptide synthesis. Finally, a late trifluoromethylation strategy with the use of Togni's reagent on disulfide-bridged peptides was also efficient to incorporate TFM or TfmCys at both N-terminal and internal positions.
Synthesizing method using serine to prepare Ramipril key intermediate
-
Paragraph 0077; 0078, (2016/10/10)
The invention relates to a synthesizing method using serine to prepare a Ramipril key intermediate. The Ramipril key intermediate is 2-azabicyclo[3.3.0] octane-3-carboxylic acid hydrochloride or benzyl ester hydrochloride. The synthesizing method includes: using the serine as the initial raw material, and sequentially performing esterification, acyl chloride acylation, deacidification, Michael addition, hydrolysis and hydrogenation reduction to obtain the Ramipril key intermediate. The synthesizing method has the advantages that the key intermediate is synthesized by a five-step method, and the synthesizing method is cheap in raw material, environmentally friendly, simple in preparation process, simple to operate, mild in reaction condition, short in reaction cycle, convenient in post-treatment, low in equipment requirement, capable of avoiding heavy metal pollution and the use of expensive catalysts, few in three wastes, high in product yield and purity and suitable for industrial production.
First RAFT polymerization of captodative 2-acetamidoacrylic acid (AAA) monomer: An experimental and theoretical study
Dedeo?lu, Burcu,U?ur, Ilke,De?irmenci, Isa,Aviyente, Viktorya,Bar?in, Bilin?,?ayli, G?khan,Acar, Havva Yagci
, p. 5122 - 5132 (2013/09/02)
A capto-dative monomer, 2-acetamidoacrylic acid (AAA), was homopolymerized through RAFT polymerization method using 2-(2-cyanopropanyl dithiobenzoate) (CPDB) as a chain transfer agent and AIBN free radical initiator in DMF at 70 C. DFT calculations were performed in the selection of the CTA for this unique monomer as well as to elucidate the influence of cd-stabilized growing radical on the kinetic parameters in comparison to methacrylic acid (MAA) and N-(prop-1-en-2-yl)acetamide (NPAA), which represent the captive and dative groups of AAA, respectively. Keq for these three monomers is in the order of AAA β > k-add for NPAA and MAA, for AAA k-add is about four orders of magnitude larger than kβ. This is the major disadvantage in the RAFT process of AAA using CPDB. Yet, poly(AAA) could be achieved with PDI as low as 1.49. Molecular weight of the polymer can be tuned by the monomer/AIBN ratio. First block copolymers of AAA with MAA and MMA using poly(AAA) as a macro-CTA were also synthesized, indicating the presence of active chain ends.
Stable triazolylphosphonate analogues of phosphohistidine
Mukai, Shin,Flematti, Gavin R.,Byrne, Lindsay T.,Besant, Paul G.,Attwood, Paul V.,Piggott, Matthew J.
, p. 857 - 874 (2012/10/07)
Histidine-phosphorylated proteins and the corresponding kinases are important components of bacterial and eukaryotic cell-signalling pathways, and are therefore potential drug targets. The study of these biomolecules has been hampered by the lability of the phosphoramidate functional group in the phosphohistidines and the lack of generic antibodies. Herein, the design and concise synthesis of stable triazolylphosphonate analogues of N1-and N3-phosphohistidine, and derivatives suitable for bioconjugation, are described. Springer-Verlag 2011.
The facile synthesis of a series of tryptophan derivatives
Blaser, Georg,Sanderson, John M.,Batsanov, Andrei S.,Howard, Judith A.K.
, p. 2795 - 2798 (2008/09/19)
This study reports a facile method for the synthesis of a variety of 5- and 6-substituted tryptophan derivatives that are difficult to prepare using alternative enzymatic approaches. Acylation of an activated amino acid, derived from serine in situ, is coupled with an enzymatic resolution step to furnish enantiopure analogues bearing a range of electron withdrawing and releasing substituents. Isolation of a dehydroalanine derivative as a by-product from some reactions provides some insights into the likely mechanism of the reaction.
Syntheses without protection: A three-step synthesis of optically active clavicipitic acid by utilizing biomimetic synthesis of 4-bromotryptophan
Yokoyama, Yuusaku,Hikawa, Hidemasa,Mitsuhashi, Masaharu,Uyama, Aki,Murakami, Yasuoki
, p. 7803 - 7806 (2007/10/03)
The optically active clavicipitic acid (4), an ergot alkaloid, was synthesized by a three-step sequence from 4-bromoindole (1). The reaction of 1 with dl-serine (2) in the presence of Ac2O followed by enzymatic kinetic resolution gave (S)-4-bromotryptophan (3). The Heck reaction of 3 with 1,1-dimethylallylalcohol in aqueous media gave clavicipitic acid in one-pot.
A Useful and Biomimetic Synthesis of N-Acyl α,β-Dehydroalanine form Aspartic Acid
Seki, Masahiko,Moriya, Tamon,Matsumoto, Kazuo
, p. 1251 - 1256 (2007/10/02)
N-Acyl α,β-dehydroalanines (1) were synthesized from the corresponding N-acyl aspartic acids by a one-pot procedure through a biomimetic oxidative β-decarboxylation.In particular, the transformation using methanol-sodium hypochlorite aqueous solution, which served for N-chlorination and dehydrochlorination, afforded good yields of (1).
Metal phosphine complex
-
, (2008/06/13)
Group IB and IIB metal phosphine complexes are disclosed. These complexes are reacted with rhodium complex precursors to form useful enantioselective hydrogenation catalysts. Also disclosed is a method of preparing useful compounds having optical activity such as natural products and compounds useful as flavors and fragrances.
