- Beam-induced dehalogenation in LSIMS: Effect of halogen type and matrix chemistry
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The LSIMS beam-induced dehalogenation of several 4-halo-phenylalanine methyl esters (I, Br, Cl, F) was investigated and compared to that of atrazine using 12 different matrix compounds including diethyl phthalate for which the empirical electron affinity was known. The extent of dehalogenation, induced by a one-electron reduction process, is in agreement with the leaving group ability of the corresponding halogens (I > Br > Cl > F) and the dehalogenation inhibiting efficiency of the matrices. The latter is rationalized in terms of electron scavenging capacity and matrix structural features relating to that capacity. The extent of dehalogenation observed for 4-I-phenylalanine methyl ester is similar to that of atrazine, a chlorinated compound, which indicates that the halogen effect is not overwhelming in determining the extent of dehalogenation. The bracketing of matrix reduction potential was attempted based on the propensity of the matrices to induce M+. formation from analytes of known oxidation potentials. The ability of matrices to induce M+. formation parallels their dehalogenation and reduction inhibiting efficiencies. The last observation underlines the importance of matrix redox properties in effecting or inhibiting beam-induced processes, be they reductive or oxidative.
- Theberge,Bertrand
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Read Online
- The synthesis and characterization of tetramic acid derivatives as Mdm2-p53 inhibitors
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We present syntheses, prediction of tautomer forms and activities of the second generation of the Mdm2-p53 inhibitors that are based on the tetramic acid scaffold. The inhibitors do not contain 6-chloroindole. Binding of these compounds to Mdm2 was checked by two orthogonal methods: the fluorescence polarization and the 1H-15N HSQC NMR titration experiments. We discovered that the 3-phenylthio-substituted tetramic acid derivatives exist in solution solely in their enol forms which is in contrast to the similar 3-aliphatic substituted derivatives. The inhibitory (Ki) and dissociation (KD) constants are in low micromolar ranges with the best binding compound 9a having KD = 2.9 μM. Furthermore, our data show that the compounds indeed bind to the p53-binding pocket of Mdm2 and do not cause dimerization of Mdm2. The current work provides solid base for further rational design of the Mdm2/p53 inhibitors.
- Muszak, Damian,?abuzek, Beata,Brela, Mateusz Z.,Twarda-Clapa, Aleksandra,Czub, Miroslawa,Musielak, Bogdan,Surmiak, Ewa,Holak, Tad A.
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p. 161 - 174
(2019/04/26)
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- Pd-catalyzed dimethylation of tyrosine-derived picolinamide for synthesis of (S)-N-Boc-2,6-dimethyltyrosine and its analogues
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A short and efficient synthesis of (S)-N-Boc-2,6-dimethyltyrosine utilizing palladium-catalyzed directed C-H functionalization is described. This represents the first general method for the ortho-dimethylation of tyrosine derivatives and offers a practical approach for preparing this synthetically important building block. Notably, throughout the reaction sequence no racemization occurs at the susceptible a-chiral centers.
- Wang, Xuning,Niu, Songtao,Xu, Lanting,Zhang, Chao,Meng, Lingxing,Zhang, Xiaojing,Ma, Dawei
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supporting information
p. 246 - 249
(2017/11/27)
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- Asymmetric chemoenzymatic synthesis of N-acetyl-α-amino esters based on lipase-catalyzed kinetic resolutions through interesterification reactions
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Several phenylalanine analogs have been synthesized through a four-step route starting from easily available ethyl acetamidocyanoacetate. In a first reaction, and making use of phase transfer catalysts, this compound reacted with several alkyl halides, being benzyltributylammonium chloride identified as the best one for the production of a series of quaternary amino acids in moderate to excellent yields (52-95%). Then, the corresponding N-acetyl-phenylalanine methyl and allyl ester derivatives were obtained through acidic hydrolysis, esterification, and N-acetylation. Rhizomucor miehei lipase was found as a versatile enzyme for the resolution of these amino esters, finding the best results through interesterification reactions with butyl butyrate in acetonitrile. A great influence in the stereoselectivity was found depending on the chemical structure of the compound, achieving for the non- or para-substituted in the phenyl ring excellent stereoselectivities, being moderate for the meta-nitro derivative, while the ortho-nitro amino ester did not react.
- Da Silva, Marcos Reinaldo,De Mattos, Marcos Carlos,De Oliveira, Maria Da Concei??o Ferreira,De Lemos, Telma Leda Gomes,Ricardo, Nágila Maria Pontes Silva,De Gonzalo, Gonzalo,Lavandera, Iván,Gotor-Fernández, Vicente,Gotor, Vicente
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p. 2264 - 2271
(2014/03/21)
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- Synthesis and biological evaluation of new active For-Met-Leu-Phe-OMe analogues containing para-substituted Phe residues
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In the present study, we report synthesis and biological evaluation of the N-Boc-protected tripeptides 4a-l and N-For protected tripeptides 5a-l as new For-Met-Leu-Phe-OMe (fMLF-OMe) analogues. All the new ligands are characterized by the C-terminal Phe residue variously substituted at position 4 of the aromatic ring. The agonism of 5a-l and the antagonism of 4a-l (chemotaxis, superoxide anion production, lysozyme release as well as receptor binding affinity) have been examined on human neutrophils. No synthesized compounds has higher activity than the standard fMLF-OMe tripeptide to stimulate chemotaxis, although compounds 5a and 5c with -CH3 and -C(CH3)3, respectively, in position 4 on the aromatic ring, are better than the standard tripeptide to stimulate the production of superoxide anion, in higher concentration. Compounds 4f and 4i, containing -F and -I in position 4, respectively, on the aromatic ring of phenylalanine, exhibit significant chemotactic antagonism. The influence of the different substitution at the position 4 on the aromatic ring of phenylalanine is discussed.
- Mollica, Adriano,Feliciani, Federica,Stefanucci, Azzurra,Costante, Roberto,Lucente, Gino,Pinnen, Francesco,Notaristefano, Daniela,Spisani, Susanna
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experimental part
p. 418 - 426
(2012/08/28)
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- Synthesis and bioactivity of novel 3-(1-hydroxyethylidene)-5-substituted- pyrrolidine-2,4-dione derivatives
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Ten novel 5-substituted derivatives of 3-(1-hydroxyethylidene)pyrrolidine- 2,4-dione were synthesized. The compounds were confirmed by IR, 1H NMR, MS and elemental analysis. The bioassay indicated that these compounds showed noticeable herbicid
- Han, Bao Feng,Shi, Qing Ming,Wang, Xian Feng,Liu, Jian Bo,Qiang, Sheng,Yang, Chun Long
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p. 1023 - 1026
(2012/10/08)
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- Enzymatic synthesis of chiral phenylalanine derivatives by a dynamic kinetic resolution of corresponding amide and nitrile substrates with a multi-enzyme system
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Mutant α-amino-ε-caprolactam (ACL) racemase (L19V/L78T) from Achromobacter obae with improved substrate specificity toward phenylalaninamide was obtained by directed evolution. The mutant ACL racemase and thermostable mutant D-amino acid amidase (DaaA) from Ochrobactrum anthropi SV3 co-expressed in Escherichia coli (pACLmut/pDBFB40) were utilized for synthesis of (R)-phenylalanine and non-natural (R)-phenylalanine derivatives (4-OH, 4-F, 3-F, and 2-F-Phe) by dynamic kinetic resolution (DKR). Recombinant E. coli with DaaA and mutant ACL racemase genes catalyzed the synthesis of (R)-phenylalanine with 84% yield and 99% ee from (RS)-phenylalaninamide (400 mM) in 22 h. (R)-Tyrosine and 4-fluoro-(R)-phenylalanine were also efficiently synthesized from the corresponding amide compounds. We also co-expresed two genes encoding mutant ACL racemase and L-amino acid amidase from Brevundimonas diminuta in E. coli and performed the efficient production of various (S)-phenylalanine derivatives. Moreover, 2-aminophenylpropionitrile was converted to (R)-phenylalanine by DKR using a combination of the non-stereoselective nitrile hydratase from recombinamt E. coli and mutant ACL racemase and DaaA from E. coli encoding mutant ACL racemase and DaaA genes. Copyright
- Yasukawa, Kazuyuki,Asano, Yasuhisa
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supporting information
p. 3327 - 3332
(2013/01/15)
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- Design, synthesis, and preliminary activity evaluation of novel peptidomimetics as aminopeptidase N/CD13 inhibitors
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The synthesis of a series of novel N-α-galloylated isoglutamic acid I-amide peptidomimetics is described. Their enzymatic inhibition against aminopeptidase N (APN/CD13) and matrix metalloproteinase-2 (MMP-2) was tested. The preliminary activity assay revealed that most of the compounds displayed selective inhibition against APN as compared with MMP-2, with IC50 values in a micromolar range. Within this series, compound 4 (IC 50a=10.2a±a.9μM) demonstrated comparable APN inhibition as compared with the positive control bestatin (IC 50a=a13.1aa0.7aμM), which might be a promising lead for further molecular optimizations. A new series of bi-peptide analogues containing amino acid or organic acid residues as elongated hydrophobic substituents inserting into S1 or S1 pocket was designed. Most of the target compounds showed potent and selective activities against APN/CD13 as compared with MMP-2. Compound 4 was comparable to bestatin and could be used as a potential lead for further development of APNIs.
- Li, Xun,Wang, Junli,Zhang, Lei,Xu, Wenfang
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experimental part
p. 494 - 504
(2011/11/04)
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- INHIBITORS OF UDP-GALACTOPYRANOSE MUTASE THWART MYCOBACTERIAL GROWTH
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Compounds which inhibit microbial growth or attenuate the virulence of pathogen microorganisms. Compounds of the invention inhibit UDP-galactopyranose mutase (UGM) and have activity as inhibitors of microbial growth of microorganisms which contain this enzyme and particularly those microorganisms in which this enzyme is responsible for the incorporation of galactofuranose residues, particularly for uridine 5'-diphosphate (UDP) galactopyranose mutase. Compounds of the invention inhibit UDP- galactopyranose mutase (UGM) and have activity to attenuate virulence of pathogenic microorganisms, including mycobacteria.
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Page/Page column 49
(2009/12/05)
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- Oleanolic acid and its derivatives: New inhibitor of protein tyrosine phosphatase 1B with cellular activities
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Protein tyrosine phosphatase 1B is a key factor in the negative regulation of insulin pathway and a promising target for treatment of diabetes and obesity. Herein, a series of competitive inhibitors were optimized from oleanolic acid, a natural triterpenoid identified against PTP1B by screening libraries of traditional Chinese medicinal herbs. Modifying at 3 and 28 positions, we obtained compound 13 with a Ki of 130 nM, which exhibited good selectivity between other phosphatases involved in insulin pathway except T-cell protein tyrosine phosphatase. Further evaluation in cell models illustrated that the derivatives enhanced insulin receptor phosphorylation in CHO/hIR cells and also stimulated glucose uptake in L6 myotubes with or addition of without insulin.
- Zhang, Yi-Nan,Zhang, Wei,Hong, Di,Shi, Lei,Shen, Qiang,Li, Jing-Ya,Li, Jia,Hu, Li-Hong
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p. 8697 - 8705
(2008/12/23)
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- Inhibitors of UDP-galactopyranose mutase thwart mycobacterial growth
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Galactofuranose (Galf) residues are fundamental components of the cell wall of mycobacteria. A key enzyme, UDP-galactopyranose mutase (UGM), that participates in Galf incorporation mediates isomerization of UDP-Galf from UDP-galactopyranose (UDP-Galp). UGM is of special interest as a therapeutic target because the gene encoding it is essential for mycobacterial viability and there is no comparable enzyme in humans. We used structure-activity relationships and molecular design to devise UGM inhibitors. From a focused library of synthetic aminothiazoles, several compounds that block the UGM from Klebsiella pneumoniae or Mycobacterium tuberculosis were identified. These inhibitors block the growth of M. smegmatis. Copyright
- Dykhuizen, Emily C.,May, John F.,Tongpenyai, Aimon,Kiessling, Laura L.
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p. 6706 - 6707
(2008/12/22)
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- SULFONAMIDE COMPOUNDS
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Certain sulfonamide compounds are dual CCK1/CCK2 inhibitors useful in the treatment of CCK1/CCK2 mediated diseases.
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Page/Page column 43-44
(2010/10/20)
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- Resolution of non-protein amino acids via the microbial protease-catalyzed enantioselective hydrolysis of their N-unprotected esters
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In the Aspergillus oryzae protease-catalyzed ester hydrolysis, substitution of N-unprotected amino acid esters for the corresponding N-protected amino acid esters resulted in a large enhancement of the hydrolysis rate, while the enantioselectivity was deteriorated strikingly when the substrates employed were the conventional methyl esters. This difficulty was overcome by employing esters bearing a longer alkyl chain such as the isobutyl ester. Utilizing this ester, amino acids carrying an aromatic side chain were resolved with excellent enantioselectivities (E=50 to >200). With amino acids bearing an aliphatic side chain also, good results in terms of the hydrolysis rate and enantioselectivity were obtained by employing such an ester as the isobutyl ester. Moreover, the enantioselectivity proved to be enhanced further by conducting the reaction at low temperature. This procedure was applicable to the case where the enantioselectivity was not high enough even by the use of the isobutyl ester.
- Miyazawa, Toshifumi,Imagawa, Kiwamu,Minowa, Hiroe,Miyamoto, Toyoko,Yamada, Takashi
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p. 10254 - 10261
(2007/10/03)
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- Substituted N-(3,5-dichlorobenzenesulfonyl)-L-prolyl-phenylalanine analogues as potent VLA-4 antagonists
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A series of substituted N-(3,5-dichlorobenzenesulfonyl)-L-prolyl- and α-methyl-L-prolyl-phenylalanine derivatives was prepared as VLA-4/VCAM antagonists. The compounds showed excellent potency with a wide variety of neutral, polar, electron withdrawing or donating groups on the phenylalanine ring (IC50～1 nM). Heteroaryl ring substitution for phenylalanine was also well tolerated. Pharmacokinetic studies in rat were performed on a representative set of compounds in both series.
- Kopka, Ihor E,Young, David N,Lin, Linus S,Mumford, Richard A,Magriotis, Plato A,MacCoss, Malcolm,Mills, Sander G,Riper, Gail Van,McCauley, Ermengilda,Egger, Linda E,Kidambi, Usha,Schmidt, John A,Lyons, Kathryn,Stearns, Ralph,Vincent, Stella,Colletti, Adria,Wang, Zhen,Tong, Sharon,Wang, Junying,Zheng, Song,Owens, Karen,Levorse, Dorothy,Hagmann, William K
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p. 637 - 640
(2007/10/03)
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- A crystallization-induced asymmetric transformation to prepare (R)-4- chlorophenylalanine methyl ester
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A second order asymmetric transformation of racemic 4- chlorophenylalanine methyl ester was achieved via salt formation with (2S,3S)-(-)-tartaric acid in the presence of salicylaldehyde to afford the desired (R)-enantiomer of 4-chlorophenylalanine methyl ester in good yield and high enantiomeric purity.
- Maryanoff, Cynthia A.,Scott, Lorraine,Shah, Rekha D.,Villani Jr., Frank J.
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p. 3247 - 3250
(2007/10/03)
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- Application of arene-ruthenium chemistry to a formal total synthesis of OF 4949 III
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A convergent formal total synthesis of OF 4949 III is described. Arene-ruthenium chemistry was used in the construction of the diaryl ether linkage in high yield, and cycloamidation under high dilution conditions (0.005 M) was achieved using DPPA as coupling reagent. SmI2 was used to reductively remove the 2-iodoethyl ester protecting group in the presence of DMPU or HMPA.
- Pearson, Anthony J.,Zhang, Penglie,Lee, Kieseung
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p. 6581 - 6586
(2007/10/03)
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- Method of treating nausea and vomiting with certain substituted-phenylalkylamino (and aminoacid) derivatives and other serotonin depleting agents
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A method for the treatment of emesis in a mammal, which method comprises administering to said mammal an emesis inhibiting amount of a compound which depletes serotonin in the brain of mammals; among which are compounds having the formula: STR1 wherein, R is selected from hydrogen, loweralkyl, trifluoromethyl, carboxyl, or loweralkoxycarbonyl; R1 and R2 are hydrogen or loweralkyl; Z is trifluoromethyl or halogen; the optical isomers and pharmaceutically acceptable salts thereof; two of the preferred compounds of the invention are fenfluramine and norfenfluramine.
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