cas 3496-11-5, Z-VAL-OSU | Articles data

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Insight into the esterase like activity demonstrated by an imidazole appended self-assembling hydrogelator
A low molecular weight hydrogelator with a covalently appended imidazole moiety is reported. Capable of percolating water in the pH range of 6 to 8, it proves to be an efficient catalyst upon self-assembly, showing Michaelis-Menten type kinetics. Activities at different pH values correlated with dramatic structural changes were observed. It can hydrolyse p-nitrophenyl acetate (pNPA) as well as inactivated esters, and l and d-phenylalanine methyl esters. The enhanced activity can be related to the conglomeration of catalytic groups upon aggregation resulting in their close proximity and the formation of hydrophobic pockets.
Singh, Nishant,Conte, Maria P.,Ulijn,Miravet, Juan F.,Escuder, Beatriu
p. 13213 - 13216
(2015)
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Coordination behaviour of new open chain and macrocyclic peptidomimetic compounds with copper(ii)
Two valine-derived bis(amino amides) ligands have been prepared and fully characterized. Both compounds contain additional functionalities that implement their basicity and their water solubility. Besides, compound 1 is an open chain ligand, while 2 is a macrocycle. Their protonation constants as well as their stability constants for the formation of the corresponding Cu2+ complexes have been determined potentiometrically. Important differences are associated to the macrocyclic effect and to the additional functionalities in the spacer. The presence of an additional amine group and/or the inclusion of a carboxylic side chain in this spacer increase the stabilities of the Cu2+complexes, suggesting its participation in the interaction with the metal. Thus, 2 is the first pseudopeptidic cyclophane of this family displaying the ability to form highly stable metal complexes in water. UV-Vis and ESI-MS were used for analyzing the complex species detected in the speciation diagram.
Wadhavane, Prashant D.,Gorla, Lingaraju,Ferrer, Armando,Altava, Belén,Burguete, M. Isabel,Izquierdo, M. ángeles,Luis, Santiago V.
p. 72579 - 72589
(2015)
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The synthesis of new fluorescent bichromophoric compounds as ratiometric pH probes for intracellular measurements
Three different bichromophoric compounds (1-3) containing an aminomethyl anthracene moiety linked to a second chromophore (pyrene, 4-nitrobenzo-2-oxa-1,3-diazole (NBD) and dansyl) through a valine-derived pseudopeptidic spacer have been prepared and their fluorescent properties studied. The results obtained show that upon irradiation the photophysical behavior of these probes involves electronic energy transfer from the excited anthracene to the second chromophore and also intramolecular photoinduced electron transfer. The X-ray structure obtained for 3 reveals that the folding associated with the pseudopeptidic spacer favours a close proximity of the two chromophores. The emissive response of 3 is clearly dependent on the pH of the medium, hence this bichromophoric compound was shown to be an excellent ratiometric pH fluorescent sensor. The emission intensity due to the anthracene moiety exhibits a decrease at neutral-basic pH values that is concomitant with an increase in the intensity arising from the dansyl fluorophore. These properties make this compound a good candidate for biological pH sensing as has been confirmed by preliminary studies with RAW 264.7 macrophage cells imaged by means of confocal fluorescence microscopy with an average pH estimation of 5.4-5.8 for acidic organelles.
Saura, A. Vanessa,Marín, María J.,Burguete, M. Isabel,Russell, David A.,Galindo, Francisco,Luis, Santiago V.
p. 7736 - 7749
(2015)
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Discovery of Peptidomimetic Antibody-Drug Conjugate Linkers with Enhanced Protease Specificity
Antibody-drug conjugates (ADCs) have become an important therapeutic modality for oncology, with three approved by the FDA and over 60 others in clinical trials. Despite the progress, improvements in ADC therapeutic index are desired. Peptide-based ADC linkers that are cleaved by lysosomal proteases have shown sufficient stability in serum and effective payload-release in targeted cells. If the linker can be preferentially hydrolyzed by tumor-specific proteases, safety margin may improve. However, the use of peptide-based linkers limits our ability to modulate protease specificity. Here we report the structure-guided discovery of novel, nonpeptidic ADC linkers. We show that a cyclobutane-1,1-dicarboxamide-containing linker is hydrolyzed predominantly by cathepsin B while the valine-citrulline dipeptide linker is not. ADCs bearing the nonpeptidic linker are as efficacious and stable in vivo as those with the dipeptide linker. Our results strongly support the application of the peptidomimetic linker and present new opportunities for improving the selectivity of ADCs.
Wei, Binqing,Gunzner-Toste, Janet,Yao, Hui,Wang, Tao,Wang, Jing,Xu, Zijin,Chen, Jinhua,Wai, John,Nonomiya, Jim,Tsai, Siao Ping,Chuh, Josefa,Kozak, Katherine R.,Liu, Yichin,Yu, Shang-Fan,Lau, Jeff,Li, Guangmin,Phillips, Gail D.,Leipold, Doug,Kamath, Amrita,Su, Dian,Xu, Keyang,Eigenbrot, Charles,Steinbacher, Stefan,Ohri, Rachana,Raab, Helga,Staben, Leanna R.,Zhao, Guiling,Flygare, John A.,Pillow, Thomas H.,Verma, Vishal,Masterson, Luke A.,Howard, Philip W.,Safina, Brian
p. 989 - 1000
(2018/01/01)

Novel fluorescent anthracene-bodipy dyads displaying sensitivity to pH and turn-on behaviour towards Cu(II) ions
Three bichromophoric compounds containing anthracene and bodipy moieties connected by different spacers have been synthesized and fully characterized. The set of spacers comprises a variety of bridges (short and flexible 1,2-diaminoethane in compound 1a, long and flexible 1,8-diaminooctane in compound 1b and short and rigid piperazine in compound 1c). The new compounds show interchromophoric communication via Electronic Energy Transfer (EET). When anthracene is excited, the energy is efficiently transferred to the bodipy moiety. The emission of the acceptor is partially quenched in dyad 1a but remarkably not in 1b and 1c. In an aqueous environment, the fluorescence of the new compounds display sensitivity to pH (emissive at acidic values and non-emissive at neutral ones), a typical behaviour of photoinduced electron-transfer (PET) probes, but with remarkable differences in the pKa of each compound, attributable to the nature of the linker. Additionally, the behaviour in the presence of several metallic cations (Cu2+, Ni2+, Cd2+, Zn2+) has been studied, and a turn-on response towards Cu2+ in water at neutral pH has been found.
Vanessa Saura,Isabel Burguete,Galindo, Francisco,Luis, Santiago V.
p. 3013 - 3024
(2017/04/10)

PROCESS FOR THE PREPARATION OF LEDIPASVIR AND INTERMEDIATES THEREOF
The present invention relates to process for preparation of ledipasvir of formula 1 and its novel intermediates. The process involves reaction of compound of formula 2 with compound of formula 3 to yield a compound of formula 4, deprotection of compound of formula 4 to yield compound of formula 5 and conversion of compound of formula 5 to Ledipasvir wherein PG is an amine protecting group provided that amino protecting group is not carbomethyloxy (-COOCH3) group; X and Y are leaving groups.
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Page/Page column 15-16

(2017/09/02)

Structure-CaSR-activity relation of kokumi γ-glutamyl peptides
Modulation of the calcium sensing receptor (CaSR) is one of the physiological activities of γ-glutamyl peptides such as glutathione (γ-glutamylcysteinylglycine). γ-Glutamyl peptides also possess a flavoring effect, i.e., sensory activity of kokumi substances, which modifies the five basic tastes when added to food. These activities have been shown to be positively correlated, suggesting that kokumi γ-glutamyl peptides are perceived through CaSRs in humans. Our research is based on the hypothesis that the discovery of highly active CaSR agonist peptides will lead to the creation of practical kokumi peptides. Through continuous study of the structure-CaSR-activity relation of a large number of γ-glutamyl peptides, we have determined that the structural requirements for intense CaSR activity of γ-glutamyl peptides are as follows: existence of an N-terminal γ-L-glutamyl residue; existence of a moderately sized, aliphatic, neutral substituent at the second residue in an L-configuration; and existence of a C-terminal carboxylic acid, preferably with the existence of glycine as the third constituent. By the sensory analysis of γ-glutamyl peptides selected by screening using the CaSR activity assay, γ-glutamylvalylglycine was found to be a potent kokumi peptide. Furthermore, norvaline-containing γ-glutamyl peptides, i.e., γ-glutamylnorvalylglycine and γ-glutamylnorvaline, possessed excellent sensory activity of kokumi substances. A novel, practical industrial synthesis of regiospecific γ-glutamyl peptides is also required for their commercialization, which was achieved through the ring opening reaction of N-α-carbobenzoxy-L-glutamic anhydride and amino acids or peptides in the presence of N-hydroxysuccinimide.
Amino, Yusuke,Nakazawa, Masakazu,Kaneko, Megumi,Miyaki, Takashi,Miyamura, Naohiro,Maruyama, Yutaka,Eto, Yuzuru
p. 1181 - 1189
(2016/08/11)

Mechanistic implications of the enantioselective addition of alkylzinc reagents to aldehydes catalyzed by nickel complexes with α-amino amide ligands
The enantioselective alkylation of aldehydes catalysed by nickel(ii)-complexes derived from α-amino amides was studied by means of density functional theory (DFT) and ONIOM (B3LYP:UFF) calculations. A mechanism was proposed in order to investigate the origin of enantioselectivity. The chirality-determining step for the alkylation was the formation of the intermediate complexes with the involvement of a 5/4/4-fused tricyclic transition state. The predominant products predicted theoretically were of (S)-configuration, in good agreement with experimental observations. The scope of the reaction was examined and high yields and enantioselectivities were observed for the enantioselective addition of Et2Zn and Me2Zn to aromatic and aliphatic aldehydes.
Escorihuela, Jorge,Burguete, M. Isabel,Ujaque, Gregori,Lledós, Agustí,Luis, Santiago V.
supporting information
p. 11125 - 11136
(2016/12/07)

PEPTIDOMIMETIC COMPOUNDS AND ANTIBODY-DRUG CONJUGATES THEREOF
This invention relates to peptidomimetic linkers and anti-body drug conjugates thereof, to pharmaceutical compositions containing them, and to their use in therapy for the prevention or treatment of cancer.
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(2015/07/07)

Fluorescent macrocyclic probes with pendant functional groups as markers of acidic organelles within live cells
A new family of acidity sensitive fluorescent macrocycles has been synthesized and fully characterized. Their photophysical properties including emission quantum yield and fluorescence lifetime have been determined. The acid-base properties of the new molecules can be tuned by the incorporation of pendant functional groups. The nature of such functional groups (carboxylic acid or ester) influences dramatically the pKa of the probes, two compounds of which exhibit low values. Preliminary intracellular studies using confocal microscopy together with emission spectra of the probes from the cellular environment have shown that the synthesized fluorescent macrocycles mark the acidic organelles of RAW 264.7 macrophage cells.
Wadhavane, Prashant D.,Izquierdo, M. Angeles,Lutters, Dennis,Burguete, M. Isabel,Marin, Maria J.,Russell, David A.,Galindo, Francisco,Luis, Santiago V.
p. 823 - 831
(2014/01/23)

C2 symmetrical nickel complexes derived from α-amino amides as efficient catalysts for the enantioselective addition of dialkylzinc reagents to aldehydes
A series of C2 symmetrical 1:2 Ni:L complexes derived from α-amino amides were studied for the enantioselective addition of dialkylzinc reagents to aldehydes. Different structural elements on the ligands seem to play an important role in determining the observed enantioselectivity. Through optimization of structure and reaction conditions, the best ligand provided secondary alcohols in excellent yields (up to 98%) and enantioselectivity of up to 99% ee for (R)-enantiomer. A transition state model has been proposed to explain the observed enantioselectivities based on computational calculations at the DFT level. Very interestingly, calculations suggest a coordination model of the aldehyde to the metal complex through association of a lone pair of the carbonyl oxygen to the hydrogen atom of an amino group.
Escorihuela, Jorge,Altava, Belen,Burguete, M. Isabel,Luis, Santiago V.
p. 551 - 558
(2013/07/27)

Efficient access to enantiopure γ4-amino acids with proteinogenic side-chains and structural investigation of γ4- asn and γ4-ser in hybrid peptide helices
Hybrid peptides composed of α- and β-amino acids have recently emerged as new class of peptide foldamers. Comparatively, γ- and hybrid γ-peptides composed of γ4-amino acids are less studied than their β-counterparts. However, recent investigations reveal that γ4-amino acids have a higher propensity to fold into ordered helical structures. As amino acid side-chain functional groups play a crucial role in the biological context, the objective of this study was to investigate efficient synthesis of γ4-residues with functional proteinogenic side-chains and their structural analysis in hybrid-peptide sequences. Here, the efficient and enantiopure synthesis of various N- and C-terminal free-γ4-residues, starting from the benzyl esters (COOBzl) of N-Cbz-protected (E)-α,β-unsaturated γ-amino acids through multiple hydrogenolysis and double-bond reduction in a single-pot catalytic hydrogenation is reported. The crystal conformations of eight unprotected γ4-amino acids (γ4-Val, γ4-Leu, γ4-Ile, γ4-Thr(OtBu), γ4-Tyr, γ4-Asp(OtBu), γ4- Glu(OtBu), and γ-Aib) reveals that these amino acids adopted a helix favoring gauche conformations along the central Cγi￡ Cβ bond. To study the behavior of γ4- residues with functional side chains in peptide sequences, two short hybrid γ-peptides P1 (Ac-Aib-γ4-Asn-Aib-γ4-Leu- Aib-γ4-Leu-CONH2) and P2 (Ac-Aib- γ4-Ser-Aib-γ4-Val-Aib-γ4-Val- CONH2) were designed, synthesized on solid phase, and their 12-helical conformation in single crystals were studied. Remarkably, the γ4-Asn residue in P1 facilitates the tetrameric helical aggregations through interhelical H bonding between the side-chain amide groups. Furthermore, the hydroxyl side-chain of γ4-Ser in P2 is involved in the interhelical H bonding with the backbone amide group. In addition, the analysis of 87 γ4-residues in peptide single-crystals reveal that the γ4-residues in 12-helices are more ordered as compared with the 10/12- and 12/14-helices. Copyright
Jadhav, Sandip V.,Misra, Rajkumar,Singh, Sumeet K.,Gopi, Hosahudya N.
supporting information
p. 16256 - 16262
(2013/12/04)

Di-Amido Gellant For Use In Consumer Product Compositions
The invention is to di-amido gellant that are suitable for use in consumer product compositions.
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(2011/10/04)

Coordination of Cu2+ Ions to C 2 Symmetric pseudopeptides derived from valine
The acid-base and coordination properties of a family of pseudopeptidic ligands with C2 symmetry derived from valine (4a-e) have been studied using a variety of techniques as a model for metal coordination in peptides and proteins. The Cu2+ cation has been selected for coordination studies, although, for comparison, some results for Zn2+ are also presented. Good agreement has been obtained between the results obtained by potentiometric titrations, spectroscopic analysis, and mass spectrometry (ESI) studies. These results highlight the potential for the use of ESI MS for characterizing the nature of the complex species formed. Clearly, the Cu 2+ complexes are much more stable than the Zn2+ complexes. While the role of the aliphatic spacer seems to be very minor in the case of the Zn2+ complexes, revealing the ability of this cation to accommodate different coordination environments, this role is critical in the case of Cu2+. Different complexes with 1:1 or 2:2 Cu2+:L stoichiometries can be formed according to the length of the spacer and the basicity of the media. This is fully illustrated by the resolution of the X-ray structures of two different Cu2+ complexes corresponding to the ligands containing a spacer with two methylene groups (ligand 4a, complex 6a [Cu2(H-1L)2](ClO4)2 with a 2:2 stoichiometry) and a propylene spacer (4b, complex 5b [CuH-2L] CH3CH2OH with a 1:1 stoichiometry).
Blasco, Salvador,Burguete, M. Isabel,Clares, M. Paz,Garcia-Espana, Enrique,Escorihuela, Jorge,Luis, Santiago V.
scheme or table
p. 7841 - 7852
(2010/11/16)

Synthesis and evaluation of pseudopeptidic fluorescence pH probes for acidic cellular organelles: In vivo monitoring of bacterial phagocytosis by multiparametric flow cytometry
A new family of fluorescent anthracenic pH probes has been synthesized, chemically characterized, and their photophysical properties have been investigated by steady-state and time-resolved fluorescence spectroscopy. The ability of these compounds to monitor pH has been investigated in solution and it was found that molecules 1-12 can act as fluorescent sensors for pH in a range between 4.6 and 6.5. This range corresponds to the pH of acidic organelles in the cell (pH 4.5-6.0) for which a limited number of probes are described. The acid-base behavior of each sensor varies slightly depending on the nature of substituents close to the amines present in the molecules. Thus, the pK a of this family of compounds can be finely tuned by the appropriate selection of the synthetic building blocks at the design stage. To test the potential diagnostic applications of this family of probes, macrocyclic pseudopeptide 2 was used to monitor the phagocytosis of a culture of GFP-labelled bacteria by human monocytic cells U937 using flow cytometry as the analytical tool. It was found that the occurrence of bacterial killing was concomitant with the production of reactive oxygen species and a drop in pH, the latter monitored indirectly by macrocyclic sensor 2, which suggests its potential use for diagnostic purposes. A new family of anthracenic macrocycles has been synthesized that can act as fluorescent probes for pH in the range 4.6-6.5. The pKa values of these compounds can be finely tuned. In flow cytometry experiments, it was found that bacterial killing by human monocytes (U937) occurred with a simultaneous drop in pH, which was monitored by one of the macrocyclic sensors.
Burguete, M. Isabel,Galindo, Francisco,Izquierdo, M. Angeles,O'Connor, Jose-Enrique,Herrera, Guadalupe,Luis, Santiago V.,Vigara, Laura
scheme or table
p. 5967 - 5979
(2011/02/26)

New chiral tetraaza ligands for the efficient enantioselective addition of dialkylzinc to aromatic aldehydes
A series of chiral tetraaza ligands were studied for the enantioselective addition of dialkylzinc to aldehydes. These bis(amino amide) ligands show high enantioselectivity in the addition of organozincs to aromatic aldehydes. Different structural elements on the ligands seem to play an important role in determining the observed enantioselectivity. Ligand 4b (N,N′-bis(N-l-valinyl)-1,3-diaminopropane, with an aliphatic spacer with 3C atoms) catalyzed the addition of Et2Zn to benzaldehyde, 1-naphtaldehyde, 4-methoxybenzaldehyde, and 4-chlorobenzaldehyde to give the corresponding alcohol products with excellent conversions and selectivities and with enantioselectivities of 99, 97, 98, and 82%, respectively. DFT calculations provide an understanding of the mechanism of the enantioselection process.
Burguete, M. Isabel,Escorihuela, Jorge,Luis, Santiago V.,Lledós, Agustí,Ujaque, Gregori
p. 9717 - 9724
(2008/12/22)

Enantioselective nickel-catalyzed conjugate addition of dialkylzinc to chalcones using chiral α-amino amides
A series of α-amino amides derived from natural amino acids (alanine, valine, phenylalanine, isoleucine, and phenylglycine) have been synthesized and fully characterized. Their Ni(II) complexes prepared from Ni(acac)2 catalyze the enantioselective conjugate addition of diethylzinc to chalcones in high yields and in good enantioselectivities (up to 84%). The side chain of the amino acid and the substituents in the amide nitrogen govern the enantioselectivity of the catalytic process.
Escorihuela, Jorge,Burguete, M. Isabel,Luis, Santiago V.
scheme or table
p. 6885 - 6888
(2009/04/07)

Novel peptidomimetic macrocycles showing exciplex fluorescence
The synthesis of five new chiral macrocyclic peptidomimetic naphthalenophanes, together with two open-chain derivatives, is described. The cyclization step is accomplished in good yields without the use of high dilution or template techniques. The new compounds have been photophysically studied by means of steady-state fluorescence spectroscopy. It has been found that the smaller the ring size, the higher the emission quantum yield from the excited charge-transfer state (CTS, exciplex) and the lower the fluorescence from the locally excited state (LES). The occurrence of exciplex fluorescence is noteworthy as the electron-donating groups are secondary amine moieties, which do not normally form emissive exciplexes.
Burguete, M. Isabel,Galindo, Francisco,Izquierdo, M. Angeles,Luis, Santiago V.,Vigara, Laura
p. 9493 - 9501
(2008/02/11)

Silver complexes of peptidomimetic polyazapyridinophanes. The influence of the bonding cavity size and the nature of side chains
Several peptidomimetic macrocycles containing a pyridine spacer and ring sizes ranging from 15 to 17 have been efficiently synthesized starting from valine and phenylalanine. The complexes formed have been investigated by potentiometry and NMR. Log K values show that phenylalanine derivatives 8 are consistently more stable than valine derivatives 7, whilst macrocycles with ring sizes of 16 members are the most appropriate for the complexation. The NMR data, in combination with molecular modeling, allow rationalization of the structure of the complexes formed and the participation of the aromatic rings from the side chain of phenylalanine in π-Ag+ interactions to be discarded. The Royal Society of Chemistry 2006.
Alfonso, Ignacio,Burguete, Isabel,Luis, Santiago V.,Miravet, Juan F.,Seliger, Piotr,Tomal, Ewa
p. 853 - 859
(2007/10/03)

Procedure for the oxidation of β-amino alcohols to α-amino aldehydes
A novel procedure for the mild oxidation of β-amino alcohols to α-amino aldehydes using commercially available manganese(IV) oxide is reported. There are several important advantages of the new method, such as high enantiopurity of the reaction and the absence of either over-oxidation or any reaction by-products during the process. A number of N-protected L-α-amino aldehydes was obtained. All new compounds were characterized by their NMR spectra and optical rotation data. Georg Thieme Verlag Stuttgart.
Sergeev, Maxim E.,Pronin, Victor B.,Voyushina, Tatiana L.
p. 2802 - 2804
(2007/10/03)

Self-assembly of small peptidomimetic cyclophanes
The self-assembly of a series of small peptidomimetic cyclophanes in organic solvents was studied. X-ray diffraction, NMR spectroscopy, and molecular modelling were used to understand the structural features of these self-assembling compounds both at the molecular and supramolecular level. The factors that could influence the formation of gels rather than crystals were studied and a model for the arrangement of molecules in the gel was proposed. Furthermore, scanning electron microscopy revealed that in some cases these compounds undergo a transcription of chirality when going from organogelator to helicoidal gel fibres.
Becerril, Jorge,Burguete, M. Isabel,Escuder, Beatriu,Galindo, Francisco,Gavara, Raquel,Miravet, Juan F.,Luis, Santiago V.,Peris, Gabriel
p. 3879 - 3890
(2007/10/03)

Efficient macrocyclization of U-turn preorganized peptidomimetics: The role of intramolecular H-bond and solvophobic effects
Simple peptidomimetic molecules derived from amino acids were reacted with meta- and parabis(bromomethyl) benzene in acetonitrile to very efficiently yield macrocyclic structures. The cyclization reaction does not require high dilution techniques and seems to be insensitive to the size of the formed macrocycle. The analysis of data obtained by 1H NMR, single-crystal X-ray diffraction, fluorescence measurements, and molecular mechanics indicate that folded conformations can preorganize the system for an efficient cyclization. The role played by intramolecular hydrogen-bonding and solvophobic effects in the presence of folded conformations is analyzed.
Becerril, Jorge,Bolte, Michael,Burguete, M. Isabel,Galindo, Francisco,Garcia-Espana, Enrique,Luis, Santiago V.,Miravet, Juan F.
p. 6677 - 6686
(2007/10/03)

O-succinimidyl-1,3-dimethyl-1,3-trimethyleneuronium salts as efficient reagents in active ester synthesis
The new uronium salts O-succinimidyl-1,3-dimethyl-1,3-trimethyleneuronium hexafluorophosphate (HSDU) and tetrafluoroborate (TSDU) have been prepared from 1,3-dimethylpropyleneurea (DMPU) and employed in the synthesis of N-hydroxysuccinimide-derived active esters. High yields were obtained at room temperature in short reaction times and no racemization was observed.
Bailén, Miguel A,Chinchilla, Rafael,Dodsworth, David J,Nájera, Carmen
p. 1661 - 1664
(2007/10/03)

Minimalist peptidomimetic cyclophanes as strong organogelators
L-Valine containing cyclophanes have been shown to gelate organic solvents leading to soft materials with a clear expression of their chirality at the supramolecular level.
Becerril, Jorge,Burguete, M. Isabel,Escuder, Beatriu,Luis, Santiago V.,Miravet, Juan F.,Querol, Manel
p. 738 - 739
(2007/10/03)

One-pot formation of succinimidyl esters by the system chlorophosphate/hydroxysuccinimide/base
Succinimidyl esters of various carboxylic acids are formed in high yield at ambient to slightly elevated temperature by the system chlorophosphate/hydroxysuccinimide/base.
Poechlauer, Peter,Hendel, Wolfram
p. 3489 - 3494
(2007/10/03)

Cathepsin B-sensitive dipeptide prodrugs. 1. A model study of structural requirements for efficient release of doxorubicin
A series of lysosomal protease-sensitive peptides attached to doxorubicin (DOX) was prepared as model substrates for internalizing anticancer immunoconjugates and potential antimetastasis prodrugs. Rates of cathepsin B-mediated release of free drug was measured for each, and human plasma stabilities for representative examples.
Dubowchik, Gene M.,Firestone, Raymond A.
p. 3343 - 3346
(2007/10/03)

Structure-Activity Study of 5-Substituted 1-Carbobenzoxy-2-iminohydantoins as Potential Anticonvulsant Agents
On the basis of our previous findings, a series of 5-substituted 2-iminohydantoins has been synthesized and tested for anticonvulsant activity to better understand the SAR of 2-iminohydantoins.Among the compounds tested, (S)-(+)-1-carbobenzoxy-2-iminohydantoin analogs with ethyl (6)-, n-propyl (7a)-, isopropyl (8)-, allyl (9)-, and sec-butyl (11)-substituted groups at the C5 of the iminohydanotin ring provided the best activities against the MES test with ED50 values in the range of 52-74 mg/kg.All of the above compounds except 8 also showed activity against the scMET test with ED50 values in the range of 141-223 mg/kg.All significantly active compounds (1, 6, 7a, 8, 9, and 11) possesed aliphatic hydrocarbon side chains of two- to three-carbon lengths at the C5 position.All of the compounds with no or minimal activity had either shorter or longer side chains.The compounds substituted at the C5 position by aryl groups, arylalkyl groups, or alkyl and arylalkyl groups containing heteroatoms also showed no activity against the MES and scMET tests.The results suggested that the C5 side chain with the correct stereochemistry in 2-iminohydantoins provides optimal anticonvulsant activity when the side chains are aliphatic hydrocarbons with a lenght, ignoring branchingg, of two to three carbons.
Sun, Zhong-Yue,Kwon, Chul-Hoon,Wurpel, John N. D.
p. 2841 - 2845
(2007/10/02)

In the search for new anticancer drugs. XXIV: Synthesis and anticancer activity of amino acids and dipeptides containing the 2-chloroethyl- and [N'- (2-chloroethyl)-N'-nitroso]-aminocarbonyl groups
A series of L,L-(42, 44, 46, and 60) and D,D-(43, 45, 47, and 61) dipeptide derivatives composed of phenylglycine, phenylalanine, homophenylalanine, and valine and containing a 2-chloroethylamino group at the C-terminus and an N'-(2-chloroethyl)-N'-nitrosoaminocarbonyl group at the N-terminus of the dipeptides were prepared. The dipeptide derivatives (42- 47, 60, and 61) were first evaluated in vivo for their anticancer activities against the murine lymphocytic leukemia P388. Compounds 42, 44, 46, and 60 possessed activities ranging from 46 to 111 percent increase in life span (%ILS), whereas 43 was marginal (%ILS = 31) and 45, 47, and 61 were inactive. In general, the L,L-series exhibited low to good activity (%ILS = 46-111), whereas the corresponding D,D-series, except for 43 (%ILS = 31), was devoid of activity. The analogously structured monoamino acid derivatives of L- alanine (74), L-phenylalanine (75), and L-aspartic acid (76) exhibited higher activity against P388 than the dipeptide derivatives (i.e., 481, 297, and 481 %ILS, respectively). The more active representatives of dipeptides (i.e., 42, 44, and 60) and the amino acids derivatives 74-76 were then tested in vivo against the murine lymphoid leukemia L1210. Compounds 42, 44, and 60 exhibited either low or marginal activity (i.e., the %ILS values were 46, 31, and 26, respectively). Compounds 74, 75, and 76 possessed low to moderate activity, as evidenced by the %ILS values of 56, 48, and 64, respectively. The %ILS parameters obtained against the P388 and L1210 tumor lines were correlated with the corresponding lipophilicities, and there is a trend towards higher activity with concomitant decrease in hydrophobicity.
Sosnovsky,Prakash,Rao
p. 1 - 10
(2007/10/02)

An improved method for the synthesis of active esters of N-protected amino acids and subsequent synthesis of dipeptides
4-Dimethylaminopyridine-catalyzed reaction of mixed carbonates 3 with N-protected amino acids 4 gave the corresponding active esters 5-9, from which dipeptides 11-18 were synthesized by aminolysis with amino acids 10.
Takeda,Ayabe,Suzuki,Konda,Harigaya
p. 689 - 691
(2007/10/02)

A Convenient Synthesis of Peptide Using Oxallates
The equimolar reactions of N-protected amino acids , amino acids or amino acid esters with oxallates (1a-1e) having active ester groups in the presence of pyridine in acetonitrile afforded the corresponding dipeptides via active esters in good yields.
Takeda, Kazuyoshi,Sawada, Izumi,Suzuki, Akira,Ogura, Haruo
p. 4451 - 4454
(2007/10/02)

SEPARATION OF ENANTIOMERS OF AMINO ACIDS BY CIRCULATION GAS CHROMATOGRAPHY IN PACKED COLUMNS
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Zabokritskii, M. P.,Rudenko, B. A.,Chizhkov, V. P.,Mitsner, B. I.,Zvonkova, E. N.
p. 806 - 812
(2007/10/02)