cas 4326-36-7, Boc-L-Tyrosine methyl ester

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Gold(I)-Catalyzed Intramolecular Hydroarylation of Phenol-Derived Propiolates and Certain Related Ethers as a Route to Selectively Functionalized Coumarins and 2 H-Chromenes
Methods are reported for the efficient assembly of a series of phenol-derived propiolates, including the parent system 56, and their Au(I)-catalyzed cyclization (intramolecular hydroarylation) to give the corresponding coumarins (e.g., 1). Simple syntheses of natural products such as ayapin (144) and scoparone (145) have been realized by such means, and the first of these subject to single-crystal X-ray analysis. A related process is described for the conversion of propargyl ethers such as 156 into the isomeric 2H-chromene precocene I (159), a naturally occurring inhibitor of juvenile hormone biosynthesis.
Cervi, Aymeric,Vo, Yen,Chai, Christina L. L.,Banwell, Martin G.,Lan, Ping,Willis, Anthony C.
p. 178 - 198
(2020/12/22)

Site-Specific Incorporation of a Photoactivatable Fluorescent Amino Acid
Photoactivatable fluorophores are emerging optical probes for biological applications. Most photoactivatable fluorophores are relatively large in size and need to be activated by ultraviolet light; this dramatically limits their applications. To introduce photoactivatable fluorophores into proteins, recent investigations have explored several protein-labeling technologies, including fluorescein arsenical hairpin (FlAsH) Tag, HaloTag labeling, SNAPTag labeling, and other bioorthogonal chemistry-based methods. However, these technologies require a multistep labeling process. Here, by using genetic code expansion and a single sulfur-for-oxygen atom replacement within an existing fluorescent amino acid, we have site-specifically incorporated the photoactivatable fluorescent amino acid thioacridonylalanine (SAcd) into proteins in a single step. Moreover, upon exposure to visible light, SAcd can be efficiently desulfurized to its oxo derivatives, thus restoring the strong fluorescence of labeled proteins.
Tang, Juan,Yu, Chenfei,Loredo, Axel,Chen, Yuda,Xiao, Han
p. 501 - 504
(2020/11/03)

Aromatic C?H Hydroxylation Reactions with Hydrogen Peroxide Catalyzed by Bulky Manganese Complexes
The oxidation of aromatic substrates to phenols with H2O2 as a benign oxidant remains an ongoing challenge in synthetic chemistry. Herein, we successfully achieved to catalyze aromatic C?H bond oxidations using a series of biologically inspired manganese catalysts in fluorinated alcohol solvents. While introduction of bulky substituents into the ligand structure of the catalyst favors aromatic C?H oxidations in alkylbenzenes, oxidation occurs at the benzylic position with ligands bearing electron-rich substituents. Therefore, the nature of the ligand is key in controlling the chemoselectivity of these Mn-catalyzed C?H oxidations. We show that introduction of bulky groups into the ligand prevents catalyst inhibition through phenolate-binding, consequently providing higher catalytic turnover numbers for phenol formation. Furthermore, employing halogenated carboxylic acids in the presence of bulky catalysts provides enhanced catalytic activities, which can be attributed to their low pKa values that reduces catalyst inhibition by phenolate protonation as well as to their electron-withdrawing character that makes the manganese oxo species a more electrophilic oxidant. Moreover, to the best of our knowledge, the new system can accomplish the oxidation of alkylbenzenes with the highest yields so far reported for homogeneous arene hydroxylation catalysts. Overall our data provide a proof-of-concept of how Mn(II)/H2O2/RCO2H oxidation systems are easily tunable by means of the solvent, carboxylic acid additive, and steric demand of the ligand. The chemo- and site-selectivity patterns of the current system, a negligible KIE, the observation of an NIH-shift, and the effectiveness of using tBuOOH as oxidant overall suggest that hydroxylation of aromatic C?H bonds proceeds through a metal-based mechanism, with no significant involvement of hydroxyl radicals, and via an arene oxide intermediate. (Figure presented.).
Masferrer-Rius, Eduard,Borrell, Margarida,Lutz, Martin,Costas, Miquel,Klein Gebbink, Robertus J. M.
p. 3783 - 3795
(2021/03/09)

General Strategy for Integrated Bioorthogonal Prodrugs: Pt(II)-Triggered Depropargylation Enables Controllable Drug Activation in Vivo
Bioorthogonal decaging reactions for controllable drug activation within complex biological systems are highly desirable yet extremely challenging. Herein, we find a new class of Pt(II)-triggered bioorthogonal cleavage reactions in which Pt(II) but not Pt(IV) complexes effectively trigger the cleavage of O/N-propargyl in a variety of ranges of caged molecules under biocompatible conditions. Based on these findings, we propose a general strategy for integrated bioorthogonal prodrugs and accordingly design a prodrug 16, in which a Pt(IV) moiety is covalently connected with an O2-propargyl diazeniumdiolate moiety. It is found that 16 can be specifically reduced by cytoplasmic reductants in human ovarian cancer cells to liberate cisplatin, which subsequently stimulates the cleavage of O2-propargyl to release large amounts of NO in situ, thus generating synergistic and potent tumor suppression activity in vivo. Therefore, Pt(II)-triggered depropargylation and the integration concept might provide a general strategy for broad applicability of bioorthogonal cleavage chemistry in vivo.
Sun, Tao,Lv, Tian,Wu, Jianbing,Zhu, Mingchao,Fei, Yue,Zhu, Jie,Zhang, Yihua,Huang, Zhangjian
p. 13899 - 13912
(2020/12/02)

Immunoproteasome Inhibitor-Doxorubicin Conjugates Target Multiple Myeloma Cells and Release Doxorubicin upon Low-Dose Photon Irradiation
Proteasome inhibitors are established therapeutic agents for the treatment of hematological cancers, as are anthracyclines such as doxorubicin. We here present a new drug targeting approach that combines both drug classes into a single molecule. Doxorubicin was conjugated to an immunoproteasome-selective inhibitor via light-cleavable linkers, yielding peptide epoxyketone-doxorubicin prodrugs that remained selective and active toward immunoproteasomes. Upon cellular uptake and immunoproteasome inhibition, doxorubicin is released from the immunoproteasome inhibitor through photoirradiation. Multiple myeloma cells in this way take a double hit: immunoproteasome inhibition and doxorubicin-induced toxicity. Our strategy, which entails targeting of a cytotoxic agent, through a covalent enzyme inhibitor that is detrimental to tumor tissue in its own right, may find use in the search for improved anticancer drugs.
Dekker, Patrick M.,Florea, Bogdan I.,Maiorana, Santina,Maurits, Elmer,Neefjes, Jacques J. C.,Overkleeft, Herman S.,Van De Graaff, Michel J.,Van Der Zanden, Sabina Y.,Van Kasteren, Sander I.,Wander, Dennis P. A.
supporting information
p. 7250 - 7253
(2020/08/06)

New Spisulosine Derivative promotes robust autophagic response to cancer cells
Therapy resistance by evasion of apoptosis is one of the hallmarks of human cancer. Therefore, restoration of cell death by non-apoptotic mechanisms is critical to successfully overcome therapy resistance in cancer. By rational drug design approach, here we try to provide evidence that subtle changes in the chemical structure of spisulosine completely switched its cytotoxic function from apoptosis to autophagy. Our most potent molecule (26b) in a series of 16 synthesized derivatives showed robust autophagic cell death in diverse cancer cells sparing normal counterpart. Compound 26b mediated lethal autophagy induction was confirmed by formation of characteristic autophagic vacuoles, LC3 puncta formation, upregulation of signature autophagy markers like Beclin and Atg family proteins. Altogether, we have detected novel autophagy inducer small molecule which can be tested further for drug discovery research.
Chaturvedi, Priyank,Datta, Dipak,Ganesher, Asha,Meena, Sanjeev,Mitra, Kalyan,Panda, Gautam,Sahai, Rohit
(2020/01/13)

BORYLATED AMINO ACID COMPOSITIONS FOR USE IN BORON NEUTRON CAPTURE THERAPY AND METHODS THEREOF
Borylated Amino Acid ("BAA") compositions and methods of making BAAs are disclosed herein. Consequently, the BAAs can be administered to patients as a Neutron Capture Agent and provide a method of treating cancer, immunological disorders and other disease by utilizing a Neutron Capture Therapy modality.
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(2020/09/19)

Synthesis, docking study and inhibitory activity of 2,6-diketopiperazines derived from α-amino acids on HDAC8
Diketopiperazines (DKPs) have been regarded as an important scaffold from the viewpoint of synthesis due to their biological properties for the treatment of several diseases, including cancer. In this work, two novel series of enantiomeric 2,6-DKPs derived from α-amino acids were synthesized through nucleophilic substitution and intramolecular cyclization reactions. All the compounds were docked against histone deacetylase 8 (HDAC8), which is a promising target for the development of anticancer drugs. These compounds bound into the active site of HDAC8 in a similar way to Trichostatin A (TSA), which is an HDAC8 inhibitor. This study showed that the conformation of the 2,6-DKP ring, stereochemistry, and the type of substituent on the chiral center had an important role in the binding modes. The Gibbs free energies and dissociation constants values of HDAC8-ligand complexes showed that compounds (S)-4hBn, (S)-4m, (R)-4h, and (R)-4m were more stable and affine towards HDAC8 than TSA. The inhibitory activities of 4a, (S)-4h, (S)- and (R)-4(g, l, m) were evaluated in vitro on HDAC8. It was found that compounds (R)-4g (IC50 = 21.54 nM) and (R)-4m (IC50 = 10.81 nM) exhibited better inhibitory activities than TSA (IC50 = 28.32 nM). These results suggested that 2,6-DKPs derivatives may be promising anticancer agents for further biological studies.
Garrido González, Flor Paulina,Mancilla Percino, Teresa
supporting information

(2020/07/21)

Photoinduced Hydroxylation of Organic Halides under Mild Conditions
Presented in this paper is photoinduced hydroxylation of organic halides, providing a mild access to a range of functionalized phenols and aliphatic alcohols. These reactions generally proceed under mild reaction conditions with no need for a photocatalyst or a strong base and show a wide substrate scope as well as excellent functional group tolerance. This work highlights the unique role of NaI that allows a challenging transformation to proceed under mild reaction conditions.
Cai, Yue-Ming,Xu, Yu-Ting,Zhang, Xin,Gao, Wen-Xia,Huang, Xiao-Bo,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
p. 8479 - 8484
(2019/10/16)

Tetrafluoropyridyl (TFP): a general phenol protecting group readily cleaved under mild conditions
Phenols are extremely valuable building blocks in the areas of pharmaceuticals, natural products, materials and catalysts. In order to carry out modifications on phenols, the phenolic oxygen is routinely protected to prevent unwanted side reactions. Presently many of the protecting groups available can require harsh conditions, specialist equipment, expensive or air/moisture-sensitive reagents to install and remove. Here we introduce the use of the tetrafluoropyridyl (TFP) group as a general protecting group for phenols. TFP can be installed in one step with no sensitivity to water or air, and it is stable under a range of commonly employed reaction conditions including acid and base. The TFP protecting group is readily cleaved under mild conditions with quantitative conversion to the parent phenol, observed in many cases in less than 1 hour.
Brittain, William D. G.,Cobb, Steven L.
supporting information
p. 2110 - 2115
(2019/02/27)

OXADIAZOLE DERIVATIVES AS RHO-KINASE INHIBITORS
The invention relates to compounds of formula (I) inhibiting Rho Kinase that are oxidazole derivatives, processes for preparing such compounds, pharmaceutical compositions containing them and therapeutic use thereof. Particularly the compounds of the invention may be useful in the treatment of many disorders associated with ROCK enzymes mechanisms, such as pulmonary diseases including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF) and pulmonary arterial hypertension (PAH).
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(2019/07/13)

Tertiary-butoxycarbonyl (Boc) – A strategic group for N-protection/deprotection in the synthesis of various natural/unnatural N-unprotected aminoacid cyanomethyl esters
A number of cyanomethyl esters of natural/unnatural aminoacids with un-protected amino functionality were synthesized because of their synthetic and medicinal importance. Critical N-Boc deprotection methods in the presence of labile (hydrolytic sensitivity) cyanomethyl functionality were screened thoroughly and it was found that readily available 4M HCl in 1,4-dioxane solution (2–4 equiv); acetonitrile, 0 °C, 2–4 h was a suitable condition. This condition was generalized and successfully applied to a variety of alkyl, alkynyl, aryl, heteroaryl, benzyl, azido, spiro amino acid cyanomethylesters irrespective of the nature of the amine (primary or secondary) and the distance between the amine and ester group to achieve final deprotected amino esters with high yield, and purity compared to other commonly known N-protecting groups (Cbz, Fmoc, Ac, Bn, Bz etc.). It was also demonstrated that N-Boc protected aminoacid cyanomethylesters are stable enough to carry out further functionalization compared to N-unprotected counterparts.
Karmakar, Ananta,Basha, Mushkin,Venkatesh Babu,Botlagunta, Murali,Malik, Noormohamed Abdul,Rampulla, Richard,Mathur, Arvind,Gupta, Arun Kumar
supporting information
p. 4267 - 4271
(2018/11/03)

TYROSINE AMIDE DERIVATIVES AS RHO- KINASE INHIBITORS
Bicyclic dihydropyrimidine-carboxamide compounds of formula I described herein inhibit Rho Kinase and may be used for the treatment of many disorders associated with ROCK enzymes mechanisms, such as pulmonary diseases including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF) and pulmonary arterial hypertension (PAH).
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Paragraph 0443-0444; 0461

(2018/08/20)

Improved binding affinities of pyrrolidine derivatives as Mcl-1 inhibitors by modifying amino acid side chains
As an important member of anti-apoptotic Bcl-2 protein, myeloid cell leukemia sequence 1 (Mcl-1) protein is an attractive target for cancer therapy. In this study, a new series of pyrrolidine derivatives as Mcl-1 inhibitors were developed by mainly modifying the amino acid side chain of compound 1. Among them, compound 18 (Ki= 0.077 μM) exhibited better potent inhibitory activities towards Mcl-1 protein compared to positive control Gossypol (Ki= 0.18 μM). In addition, compound 40 possessed good antiproliferative activities against PC-3 cells (Ki= 8.45 μM), which was the same as positive control Gossypol (Ki= 7.54 μM).
Wan, Yichao,Liu, Tingting,Li, Xiaoxian,Chen, Chen,Fang, Hao
p. 138 - 152
(2016/12/22)

Improving target amino acid selectivity in a permissive aminoacyl tRNA synthetase through counter-selection
The amino acid acridon-2-ylalanine (Acd) can be a valuable probe of protein dynamics, either alone or as part of a F?rster resonance energy transfer (FRET) or photo-induced electron transfer (eT) probe pair. We have previously reported the genetic incorporation of Acd by an aminoacyl tRNA synthetase (RS). However, this RS, developed from a library of permissive RSs, also incorporates N-phenyl-aminophenylalanine (Npf), a trace byproduct of one Acd synthetic route. We have performed negative selections in the presence of Npf and analyzed the selectivity of the resulting AcdRSs by in vivo protein expression and detailed kinetic analyses of the purified RSs. We find that selection conferred a ～50-fold increase in selectivity for Acd over Npf, eliminating incorporation of Npf contaminants, and allowing one to use a high yielding Acd synthetic route for improved overall expression of Acd-containing proteins. More generally, our report also provides a cautionary tale on the use of permissive RSs, as well as a strategy for improving selectivity for the target amino acid.
Sungwienwong, Itthipol,Hostetler, Zachary M.,Blizzard, Robert J.,Porter, Joseph J.,Driggers, Camden M.,Mbengi, Lea Z.,Villegas, José A.,Speight, Lee C.,Saven, Jeffery G.,Perona, John J.,Kohli, Rahul M.,Mehl, Ryan A.,Petersson, E. James
supporting information
p. 3603 - 3610
(2017/07/07)

New reagent for the introduction of Boc protecting group to amines: Boc-OASUD
A new reagent, tert-butyl (2,4-dioxo-3-azaspiro [5,5] undecan-3-yl) carbonate (Boc-OASUD) for the preparation of N-Boc-amino acids is described. The Boc-OASUD reacts with amino acids and their esters at room temperature in the presence of a base and gives N-Boc-amino acids and their esters in good yields and purity. Introduction of the Boc group takes place without racemization. The Boc-OASUD, being a solid and more stable, is a better alternative to di-tert-butyl dicarbonate which is low melting and has to be dispensed in plastic containers than glass because of its poor stability.
Maheswara Rao, B. Leela,Nowshuddin, Shaik,Jha, Anjali,Divi, Murali K.,Rao
supporting information
p. 2127 - 2132
(2017/10/31)

Vinyl Ether/Tetrazine Pair for the Traceless Release of Alcohols in Cells
The cleavage of a protecting group from a protein or drug under bioorthogonal conditions enables accurate spatiotemporal control over protein or drug activity. Disclosed herein is that vinyl ethers serve as protecting groups for alcohol-containing molecules and as reagents for bioorthogonal bond-cleavage reactions. A vinyl ether moiety was installed in a range of molecules, including amino acids, a monosaccharide, a fluorophore, and an analogue of the cytotoxic drug duocarmycin. Tetrazine-mediated decaging proceeded under biocompatible conditions with good yields and reasonable kinetics. Importantly, the nontoxic, vinyl ether duocarmycin double prodrug was successfully decaged in live cells to reinstate cytotoxicity. This bioorthogonal reaction presents broad applicability and may be suitable for in vivo applications.
Jiménez-Moreno, Ester,Guo, Zijian,Oliveira, Bruno L.,Albuquerque, Inês S.,Kitowski, Annabel,Guerreiro, Ana,Boutureira, Omar,Rodrigues, Tiago,Jiménez-Osés, Gonzalo,Bernardes, Gon?alo J. L.
supporting information
p. 243 - 247
(2016/12/30)

Chiral ethylene-bridged flavinium salts: the stereoselectivity of flavin-10a-hydroperoxide formation and the effect of substitution on the photochemical properties
A series of chiral non-racemic N1,N10-ethylene bridged flavinium salts 4 was prepared using enantiomerically pure 2-substituted 2-aminoethanols (R = isopropyl, phenyl, benzyl, 4-methoxybenzyl, 4-benzyloxybenzyl) derived from amino acids as the sole source of chirality. The flavinium salts were shown to form 10a-hydroperoxy- and 10a-methoxy-adducts with moderate to high diastereoselectivity depending on the ethylene bridge substituent originating from the starting amino acid. High diastereoselectivities (dr values from 80:20 to >95:5) were observed for flavinium salts bearing benzyl substituents attached to the ethylene bridge. The benzyl group preferred the face-to-face (syn) orientation relative to the flavinium unit; thereby effectively preventing nucleophilic attack from one side. This conformation was found to be the most stable according to the DFT calculations. Consequently, the presence of benzyl groups causes intermolecular fluorescence quenching resulting in a significant decrease in the fluorescence quantum yield from 11% for 4a bearing an isopropyl substituent to 0.3% for 4c containing a benzyl group and to a value lower than 0.1% for the benzyloxybenzyl derivative 4e.
?urek, Ji?í,Svobodová, Eva,?turala, Ji?í,Dvo?áková, Hana,Svoboda, Ji?í,Cibulka, Radek
p. 1780 - 1791
(2017/11/17)

Synthesis, in Vitro Evaluation, and Radiolabeling of Fluorinated Puromycin Analogues: Potential Candidates for PET Imaging of Protein Synthesis
There is currently no ideal radiotracer for imaging of protein synthesis rate (PSR) by positron emission tomography (PET). Existing fluorine-18-labeled amino acid-based radiotracers predominantly visualize amino acid transporter processes, and in many cases they are not incorporated into nascent proteins at all. Others are radiolabeled with the short-half-life positron emitter carbon-11, which is rather impractical for many PET centers. Based on the puromycin (6) structural manifold, a series of 10 novel derivatives of 6 was prepared via Williamson ether synthesis from a common intermediate. A bioluminescence assay was employed to study their inhibitory action on protein synthesis, which identified the fluoroethyl analogue 7b as a lead compound. The fluorine-18 analogue was prepared via nucleophilic substitution of the corresponding tosylate precursor in a modest radiochemical yield of 2 ± 0.6% with excellent radiochemical purity (>99%) and showed complete stability over 3 h at ambient temperature.
Betts, Helen M.,Milicevic Sephton, Selena,Tong, Carmen,Awais, Ramla O.,Hill, Philip J.,Perkins, Alan C.,Aigbirhio, Franklin I.
supporting information
p. 9422 - 9430
(2016/11/11)

Tyrosine-Based Ionic Liquid Crystals: Switching from a Smectic A to a Columnar Mesophase by Exchange of the Spherical Counterion
Synthetic strategies were developed to prepare l-tyrosine-based ionic liquid crystals with structural variations at the carboxylic and phenolic OH groups as well as the amino functionality. Salt metathesis additionally led to counterion variation. The liquid-crystalline properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS, SAXS). The symmetrical ILC chlorides bearing the same alkyl chain at both the ester and ether but either an acyclic or cyclic guanidinium group displayed enantiotropic SmA2mesophases with phase widths of 31–88 K irrespective of the head group. It was particularly the replacement of chloride in the acyclic guanidinium ILC by hexafluorophosphate that induced a phase change from SmA2to Colr. This phase change was attributed to a higher curvature of the interface due to the larger anion, which increased the effective head group cross-sectional area of the amphiphilic ILC. The unsymmetrical acyclic guanidinium chlorides, bearing a constant C14ester and variable alkyl chains on the phenolic position, formed enantiotropic SmA2phases. The derivative with the largest difference in chain lengths, however, displayed a Colrphase, resulting from discoid aggregates of the cone-shaped guanidinium chloride. The results are discussed in terms of the packing parameters, which indicate that the phase behaviour of the thermotropic tyrosine-based ILCs shows analogies to those of lyotropic liquid crystals.
Neidhardt, Manuel M.,Wolfrum, Manpreet,Beardsworth, Stuart,W?hrle, Tobias,Frey, Wolfgang,Baro, Angelika,Stubenrauch, Cosima,Giesselmann, Frank,Laschat, Sabine
supporting information
p. 16494 - 16504
(2016/11/09)

Preparation method of alanine derivatives
The invention discloses a method for preparing alanine derivatives disclosed as Formula (I). The alanine derivatives can be used as a synthesis intermediate of an opioid receptor regulator, such as a synthesis intermediate of eluxadoline. By using the cheap and accessible chiral tyrosine as the initial raw material, the invention provides a brand-new synthesis route for preparing alanine derivatives. The whole reaction route has the advantages of high total yield, low cost and mild reaction conditions, is simple and safe for operation, and is suitable for large-scale industrial production.
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Paragraph 0076; 0077; 0078

(2016/10/08)

Synthesis of Met-enkephalin by solution-phase peptide synthesis methodology utilizing para-toluene sulfonic acid as N-terminal masking of l-methionine amino acid
The Met-enkephalin, Tyr-Gly-Gly-Phe-Met, was synthesized by the solution-phase synthesis (SPS) methodology employing -OBzl group as carboxyls' protection, while the t-Boc groups were employed for the N-terminal α-amines' protection for the majority of the amino acids of the pentapeptide sequence. The l-methionine (l-Met) amino acid was used as PTSA.Met-OBzl obtained from the simultaneous protection of the α-amino, and carboxyl group with para-toluene sulfonic acid (PTSA) and as-OBzl ester, respectively in a C-terminal start of the 2?+?2?+?1 fragments condensation convergent synthetic approach. The protection strategy provided a short, single-step, simultaneous, orthogonal, nearly quantitative, robust, and stable process to carry through the protected l-methionine and l-phenylalanine coupling without any structural deformities during coupling and workups. The structurally confirmed final pentapeptide product was feasibly obtained in good yields through the current approach.
Khan, Riaz A.
p. 884 - 888
(2016/11/11)

Synthesis of MeO-PEG2000-supported chiral ferrocenyl oxazoline carbinol ligand and its application in asymmetric catalysis
A simple method for the synthesis of a MeO-PEG-supported chiral ferrocenyl oxazoline carbinol ligand has been developed. The chiral ligand was successfully applied to the catalytic asymmetric addition of diethylzinc to aryl aldehydes, affording secondary alcohols in high yields and with excellent enantioselectivities (up to 94% ee). The chiral ligand can be recovered and reused twice with no apparent loss of catalyst efficiency.
Zhao, Wen-Xian,Liu, Guan-Jun,Wang, Jingjing,Li, Feng,Liu, Lantao
p. 1133 - 1144
(2016/11/11)

Discovery of acyl guanidine tryptophan hydroxylase-1 inhibitors
An increasing number of diseases have been linked to a dysfunctional peripheral serotonin system. Given that tryptophan hydroxylase 1 (TPH1) is the rate limiting enzyme in the biosynthesis off serotonin, it represents an attractive target to regulate peripheral serotonin. Following up to our first disclosure, we report a new chemotype of TPH1 inhibitors where-by the more common central planar heterocycle has been replaced with an open-chain, acyl guanidine surrogate. Through our work, we found that compounds of this nature provide highly potent TPH1 inhibitors with favorable physicochemical properties that were effective in reducing murine intestinal 5-HT in vivo. Furthermore, we obtained a high resolution (1.90 ?) X-ray structure crystal structure of one of these inhibitors (compound 51) that elucidated the active conformation along with revealing a dimeric form of TPH1 for the first time.
Goldberg, Daniel R.,De Lombaert, Stéphane,Aiello, Robert,Bourassa, Patricia,Barucci, Nicole,Zhang, Qing,Paralkar, Vishwas,Stein, Adam J.,Valentine, Jim,Zavadoski, William
supporting information
p. 2855 - 2860
(2016/06/06)

Method for preparing alanine derivative
The invention discloses a method for preparing an alanine derivative represented by a formula (I) shown in the description. The alanine derivative can serve as synthesis intermediates of opium receptor regulators, such as a synthesis intermediate of eluxadoline. According to the method, chiral tyrosine which is cheap and readily available serves as an initial raw material, a bran-new synthesis route for preparing the alanine derivative is provided, the total yield of the entire reaction route is high, the cost is low, the reaction conditions are mild, and the operation is simple and safe, so that the method is applicable to large-scale industrial production.
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(2016/10/10)

Synthesis, bioactivity, docking and molecular dynamics studies of furan-based peptides as 20s proteasome inhibitors
Proteasome inhibitors are promising compounds for a number of therapies, including cardiovascular and eye diseases, diabetes, and cancers. We previously reported a series of furanbased peptidic inhibitors with moderate potencies against the proteasome b5 subunit, hypothesizing that the C-terminal furyl ketone motif could form a covalent bond with the catalytic residue, threonine 1. In this context, we describe further optimizations of the furan-based peptides, and a series of dipeptidic and tripeptidic inhibitors were designed and synthesized, aiming at improved potency and better solubility. Most of the tripeptidic inhibitors demonstrated improved potency and selectivity as b5 subunit inhibitors in both enzymatic and cellular assays, and good antineoplastic activities in various tumor cell lines were also observed. However, no inhibitory effects were observed for the dipeptidic compounds, which led us to presume that a noncovalent binding mode is adopted. Docking studies and molecular dynamics simulations were carried out to verify this presumption, with results showing that the distance between the furyl ketone motif and Thr1 is slightly too long to form covalent bond.
Sun, Qi,Xu, Bo,Niu, Yan,Xu, Fengrong,Liang, Lei,Wang, Chao,Yu, Jiapei,Yan, Gang,Wang, Wei,Jin, Hongwei,Xu, Ping
p. 498 - 510
(2015/03/18)

MAO-B SELECTIVE INHIBITOR COMPOUNDS, PHARMACEUTICAL COMPOSITIONS THEREOF AND USES THEREOF
Described herein are a series of compounds having the structure of Formula I for use in the inhibition of MAO and uses thereof for the treatment of a barrier disease, obesity, solid epithelial cell tumor metastasis, diabetes, an auto-immune and inflammatory disease or a cardiometabolic disorder.
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(2015/03/16)

ACYLGUANIDINES AS TRYPTOPHAN HYDROXYLASE INHIBITORS
The present invention is directed to acylguanidines which are inhibitors of tryptophan hydroxylase (TPH), particularly isoform 1 (TPHl), that are useful in the treatment of diseases or disorders associated with peripheral serotonin including, for example, gastrointestinal, cardiovascular, pulmonary, inflammatory, metabolic, and low bone mass diseases, as well as serotonin syndrome, and cancer.
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(2015/06/25)

Synthesis and conformation studies of rubiyunnanin B analogs
Five new analogs 4-8 of rubiyunnanin B (1), mainly modified on the tetrapeptide subunit, were synthesized. These agents 4-8 were substituted d-Ala-l-Ala-l-Tyr(OMe)-l-Ala, d-Ala-l-Ala-l-Phe-l-Ala, d-Ala-l-Ala-l-Try-l-Ala, d-Ala-l-Ala-l-Pro-l-Ala, and d-Ala-l-Ala-l-Ala for the d-Ala-l-Ala-l-N-Me-Tyr(OMe)-l-Ala tetrapeptide subunit. Unlike the natural product, the synthetic agents 4-8 adopt only a single solution conformation, and the central peptide bond in the cyclodityrosine subunit of compounds 4-8 adopt trans stereochemistry. Cytotoxic activities of analogs 4-8 against three human cancer cell lines including A549, BGC-823, and HeLa were evaluated and all the five synthesized peptides exhibited no effects against the test cell lines. These compounds were also evaluated for their antiinsulin resistance and insulin sensitizing activities and none of them showed activity in these assays.
Liu, Na-Na,Zhao, Si-Meng,Zhao, Jing-Feng,Zeng, Guang-Zhi,Tan, Ning-Hua,Liu, Jian-Ping
p. 6630 - 6640
(2015/03/30)

General solvent-free highly selective N-tert-butyloxycarbonylation strategy using protic ionic liquid as an efficient catalyst
A simple, rapid and solvent-free protocol is described for the chemo-selective transformation of amines to tert-butyloxycarbonyl protected derivatives (NHBoc) using Boc2O and imidazolium trifluoroacetate protic ionic liquid (5-20 mol%). Unwanted side products such as isocyanate, urea or N,N-di-Boc were not detected. The scope of the protection strategy was successfully explored for substrate alcohols, phenols and thiol at elevated temperatures. Optically pure amino acids, amino acid esters and amino alcohols were efficiently converted to the corresponding N-Boc protected derivatives in excellent yields without racemization at the chiral center. The distinct advantages of this method are: operational simplicity, cleaner reaction, high selectivity, excellent yield, rapid reaction convergence, easy preparation and recyclability of the catalyst.
Majumdar, Swapan,De, Jhinuk,Chakraborty, Ankita,Maiti, Dilip K.
p. 24544 - 24550
(2014/07/07)

Biotinylated amphiphile-single walled carbon nanotube conjugate for target-specific delivery to cancer cells
The present work reports the specific targeting of cancerous cells using a non-covalently water dispersed nanoconjugate of biotinylated amphiphile-single walled carbon nanotube (SWNT). The fundamental approach involves incorporation of the biotin into the architecture of the carbon nanotube (CNT) dispersing agent to develop a multifaceted delivery vehicle having a high colloidal stability, substantial cell viability and targeted specificity towards cancer cells. A three way functionalization strategy was employed to introduce a C-16 hydrophobic segment, polyethylene glycol hydrophilic fragment and biotin as the target-specific unit at the -OH, -COOH and -NH2 terminals of l-tyrosine, respectively. The newly developed neutral amphiphile exhibited an efficient SWNT dispersion (72%) in water, significant viability of different mammalian cells (Hela, HepG2, CHO and HEK-293) up to 48 h and also media stability. Most importantly, the biotinylated amphiphile-SWNT dispersion successfully transported the fluorescently labelled Cy3-oligoneucleotide (loaded on the surface of CNT) inside the cancerous Hela, HepG2 cells after 3 h of incubation, in contrast to CHO and HEK-293 cells (devoid of overexpressed biotin receptors). The presence of the biotin moiety in the cellular transporters facilitated the internalization of cargo due to the overexpressed biotin receptors in the cancer cells. Importantly, this nanohybrid was also capable of specifically transporting the anticancer drug doxorubicin to cancer cells, which led to the significant killing of Hela cells compared to the normal CHO cells. Thus, the receptor-mediated specific transportation of cargo into cancer cells was possible only due to the biotinylated CNT dispersing agent. To the best of our knowledge this is the first reported amino acid based biotinylated small amphiphilic molecule that non-covalently dispersed SWNTs and the corresponding nanoconjugate showed excellent cell viability, antibiofouling properties and the desired target-specific drug delivery.
Brahmachari, Sayanti,Ghosh, Moumita,Dutta, Sounak,Das, Prasanta Kumar
p. 1160 - 1173
(2014/03/21)

Reductive removal of methoxyacetyl protective group using sodium borohydride
Herein, we have developed a mild and selective reductive deprotection method for the MAc protected alcohols using sodium borohydride. The new deprotection conditions provide a complete orthogonality between O-MAc and other protecting groups such as tert-butyl ester, N-Boc, Fmoc, Cbz, O-TBDMS, N-benzyl, O-benzyl, O-acetyl, N-acetyl, N-MAc, etc. In addition to O-MAc deprotection, this method is also applicable for S-MAc deprotection.
Gadekar, Pradip K.,Hoermann, Maryann,Corbo, Faith,Sharma, Rajiv,Sarveswari,Roychowdhury, Abhijit
p. 503 - 506
(2014/01/06)

Preparation of phenylethylbenzamide derivatives as modulators of DNMT3 activity
DNA-methyltransferases (DNMTs) are a class of epigenetic enzymes that catalyze the transfer of a methyl moiety from the methyl donor S-adenosyl-l-methionine onto the C5 position of cytosine in DNA. This process is dysregulated in cancers and leads to the hypermethylation and silencing of tumor suppressor genes. The development of potent and selective inhibitors of DNMTs is of utmost importance for the discovery of new therapies for the treatment of cancer. We report herein the synthesis and DNMT inhibitory activity of 29 analogues derived from NSC 319745. The effect of selected compounds on the methylation level in the MDA-MB-231 human breast cancer cell line was evaluated using a luminometric methylation assay. Molecular docking studies have been conducted to propose a binding mode for this series.
Kabro, Anzhelika,Lachance, Hugo,Marcoux-Archambault, Iris,Perrier, Valerie,Dore, Vicky,Gros, Christina,Masson, Veronique,Gregoire, Jean-Marc,Ausseil, Frederic,Cheishvili, David,Laulan, Nathalie Bibens,St-Pierre, Yves,Szyf, Moshe,Arimondo, Paola B.,Gagnon, Alexandre
p. 1562 - 1570
(2013/12/04)

Total synthesis of a pyrrolidin-2-one with the structure proposed for the alkaloid rigidiusculamide A
The total synthesis of the pyrrolidinone alkaloid rigidiusculamide A is reported starting from L-tyrosine, using amidation, ring-closing metathesis, and dihydroxylation as the key reactions. Copyright
Radha Krishna, Palakodety,Karunakar Reddy, Bonepally
p. 1564 - 1570
(2013/09/02)

The synthesis of 13C9-15N-labeled 3,5-diiodothyronine and thyroxine
Thyroid hormones undergo extensive metabolism to regulate hormone activity. A labeled thyroid hormone would be useful to track hormone metabolism through various pathways. While radiolabeled thyroid hormones have been synthesized and used for in vivo studies, a stable isotope labeled form of thyroid hormone is required for studying thyroid hormone metabolism by LC-MS/MS, an analytical technique that has certain advantages without the complications of radioactivity. Here we report the synthesis of 13C9- 15N-T2 and 13C9-15N- T4, two labeled thyroid hormone derivatives suitable for in vivo LC-MS/MS studies. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
Hackenmueller, Sarah A.,Scanlan, Thomas S.
p. 1439 - 1446
(2013/05/22)

New β-strand templates constrained by Huisgen cycloaddition
New peptidic templates constrained into a β-strand geometry by linking acetylene and azide containing P1 and P3 residues of a tripeptide by Huisgen cycloaddition are presented. The conformations of the macrocycles are defined by NMR studies and those that best define a β-strand are shown to be potent inhibitors of the protease calpain. The β-strand templates presented and defined here are prepared under optimized conditions that should be suitable for targeting a range of proteases and other applications requiring such a geometry.
Pehere, Ashok D.,Abell, Andrew D.
supporting information; experimental part
p. 1330 - 1333
(2012/05/20)

A rationally designed pyrrolysyl-tRNA synthetase mutant with a broad substrate spectrum
Together with tRNACUAPyl, a rationally designed pyrrolysyl-tRNA synthetase mutant N346A/C348A has been successfully used for the genetic incorporation of a variety of phenylalanine derivatives with large para substituents into superfolder green fluorescent protein at an amber mutation site in Escherichia coli. This discovery greatly expands the genetically encoded noncanonical amino acid inventory and opens the gate for the genetic incorporation of other phenylalanine derivatives using engineered pyrrolysyl-tRNA synthetase-tRNACUAPyl pairs.
Wang, Yane-Shih,Fang, Xinqiang,Wallace, Ashley L.,Wu, Bo,Liu, Wenshe R.
supporting information; experimental part
p. 2950 - 2953
(2012/04/10)

Two modes of asymmetric polymerization of phenylacetylenes having an L -amino alcohol residue and two hydroxy groups
Four novel chiral phenylacetylenes having an L-amino alcohol residue and two hydroxymethyl groups were synthesized and polymerized by an achiral catalyst ((nbd)Rh+[η6-(C6H5)B -(C6H5)3]) or a chiral catalytic system ([Rh(nbd)Cl]2/(S)- or (R)-phenylethylamine ((S)- or (R)-PEA)). The two resulting polymers having an L-valinol or L-phenylalaninol residue showed Cotton effects at wavelengths around 430 nm. This observation indicated that they had an excess of one-handed helical backbones. Positive and negative Cotton effects were observed only for the polymers having an L-valinol residue produced by using (R)- and (S)-PEA as a cocatalyst, respectively, although the monomer had the same chirality. Even when the achiral catalyst was used, the two resulting polymers having an L-valinol or L-phenylalaninol residue showed Cotton effects despite the long distance between the chiral groups and the main chain. We have found the first example of a new type of chiral monomer, that is, a chiral phenylacetylene monomer having an L-amino alcohol residue and two hydroxy groups that was suitable for both modes of asymmetric polymerization, that is, the helix-sense-selective polymerization (HSSP) with the chiral catalytic system and the asymmetric-induced polymerization (AIP) with the achiral catalyst. The other two monomers having L-alaninol and L-tyrosinol were found to be unsuitable to neither HSSP nor AIP because of their polymers' low solubility.
Jia, Hongge,Li, Jun,Zang, Yu,Aoki, Toshiki,Teraguchi, Masahiro,Kaneko, Takashi
p. 5134 - 5143
(2013/01/15)

Synthesis and biological evaluation of tyrosine modified analogues of the α4β7 integrin inhibitor biotin-R8ERY
The α4β7 integrin is a well-known target for the development of drugs against various inflammatory disease states including inflammatory bowel disease, type 1 diabetes and multiple sclerosis. The synthesis of a small library of cell-permeable β7 integrin inhibitors based on the peptide biotin-R8ERY is reported, in which the tyrosine residue has been modified by using the Suzuki-Miyaura cross-coupling reaction. The synthesised peptidomimetics were evaluated in a cell adhesion assay and shown to inhibit Mn2+-activated adhesion of mouse TK-1 T cells to mouse MAdCAM-1. All of the synthesised peptidomimetics are more active than our previously reported lead compound biotin-R8ERY with two of the analogues, 6 and 7, exhibiting IC50 values of 15 μM.
Papst, Stefanie,Noisier, Anais F.M.,Brimble, Margaret A.,Yang, Yi,Krissansen, Geoffrey W.
supporting information
p. 5139 - 5149
(2012/11/07)

Photorelease of tyrosine from α-carboxy-6-nitroveratryl (αCNV) derivatives
The synthesis of photolabile tyrosine derivatives protected on the phenolic oxygen by the α-carboxy-6-nitroveratryl (αCNV) protecting group is described. The compounds undergo rapid photolysis at wavelengths longer than 300 nm to liberate the corresponding phenol in excellent yield (quantum yield for the deprotection of tyrosine = 0.19). Further protection of caged tyrosine is possible, yielding N-Fmoc protected derivatives suitable for direct incorporation of caged tyrosine in solid-phase peptide synthesis.
Russell, Alexander G.,Sadler, Matthew J.,Laidlaw, Helen J.,Gutierrez-Loriente, Agustin,Wharton, Christopher W.,Carteau, David,Bassani, Dario M.,Snaith, John S.
scheme or table
p. 556 - 563
(2012/06/30)

Designer nanorings with functional cavities from self-assembling β-Sheet peptides
β-Barrel proteins that take the shape of a ring are common in many types of water-soluble enzymes and water-insoluble transmembrane pore-forming proteins. Since β-barrel proteins perform diverse functions in the cell, it would be a great step towards developing artificial proteins if we can control the polarity of artificial β-barrel proteins at will. Here, we describe a rational approach to construct β-barrel protein mimics from the self-assembly of peptide-based building blocks. With this approach, the direction of the self-assembly process toward the formation of water-soluble β-barrel nanorings or water-insoluble transmembrane β-barrel pores could be controlled by the simple but versatile molecular manipulation of supramolecular building blocks. This study not only delineates the basic driving force that underlies the folding of β-barrel proteins, but also lays the foundation for the facile fabrication of β-barrel protein mimics, which can be developed as nanoreactors, ion- and small-molecule-selective pores, and novel antibiotics. Copyright
Park, Il-Soo,Yoon, You-Rim,Jung, Minseon,Kim, Kimoon,Park, Seongbyeong,Shin, Seokmin,Lim, Yong-Beom,Lee, Myongsoo
supporting information; experimental part
p. 452 - 458
(2011/10/03)

Regioselective ring-opening of amino acid-derived chiral aziridines: An easy access to cis-2,5-disubstituted chiral piperazines
An efficient four-step synthetic strategy for cis-2,5-disubstituted chiral piperazines derived from amino-acid-based aziridines is described. The key steps in this strategy are the highly regioselective boron trifluoride diethyl etherate (BF3·OEt2)-mediated ring-opening of less-reactive N-Ts chiral aziridines by α-amino acid methyl ester hydrochloride followed by Mitsunobu cyclization. This protocol has been used in an attempt to construct the piperazine core framework of natural product (+)-piperazinomycin. The pied piperazines: A four-step efficient synthetic strategy for cis-2,5-disubstituted chiral piperazines derived from amino acid-based aziridines is described. The key reaction steps are the highly regioselective BF3·OEt2 mediated ring-opening of less-reactive N-Ts chiral aziridines by α-amino acid methyl ester hydrochlorides, followed by a Mitsunobu cyclization. This protocol has been used in an attempt to construct the piperazine core framework of natural product (+)-piperazinomycin. Copyright
Samanta, Krishnananda,Panda, Gautam
scheme or table
p. 189 - 197
(2011/10/08)

Nickel-catalyzed cross-coupling of aryl phosphates with arylboronic acids
The Suzuki-Miyaura cross-coupling of aryl phosphates using Ni(PCy 3)2Cl2 as an inexpensive, bench-stable catalyst is described. Broad substrate scope and high efficiency are demonstrated by the syntheses of more than 40 biaryls and by constructing complex organic molecules. The poor reactivity of aryl phosphates relative to aryl halides is successfully employed to construct polyarenes by selective cross-coupling using Pd and Ni catalysts.
Chen, Hu,Huang, Zhongbin,Hu, Xiaoming,Tang, Guo,Xu, Pengxiang,Zhao, Yufen,Cheng, Chien-Hong
scheme or table
p. 2338 - 2344
(2011/05/30)

Nonsolvent application of ionic liquids: Organo-catalysis by 1-alkyl-3-methylimidazolium cation based room-temperature ionic liquids for chemoselective N-tert-butyloxycarbonylation of amines and the influence of the C-2 hydrogen on catalytic efficiency
1-Alkyl-3-methylimidazolium cation based ionic liquids efficiently catalyze N-tert-butyloxycarbonylation of amines with excellent chemoselectivity. The catalytic role of the ionic liquid is envisaged as "electrophilic activation" of di-tert-butyl dicarbonate (Boc2O) through bifurcated hydrogen bond formation with the C-2 hydrogen of the 1-alkyl-3-methylimidazolium cation and has been supported by a downfield shift of the imidazolium C-2 hydrogen of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][NTf2]) from δ 8.39 to 8.66 in the presence of Boc2O in the 1H NMR and a drastic reduction of the catalytic efficiency with 1-butyl-2,3-dimethylimidazolium ionic liquids that are devoid of the C-2 hydrogen. The differential time required for reaction with aromatic and aliphatic amines has offered means for selective N-t-Boc formation during inter and intramolecular competitions. Preferential N-t-Boc formation with secondary aliphatic amine has been achieved in the presence of primary aliphatic amine. Comparison of the catalytic efficiency for N-t-Boc formation with a common substrate revealed that [bmim][NTf2] is superior to the reported Lewis acid catalysts.
Sarkar, Anirban,Roy, Sudipta Raha,Parikh, Naisargee,Chakraborti, Asit K.
experimental part
p. 7132 - 7140
(2011/10/08)

MODULATORS OF THE GPR119 RECEPTOR AND THE TREATMENT OF DISORDERS RELATED THERETO
The present invention relates to compounds of Formula (Ia) and pharmaceutically acceptable salts, solvates, and hydrates thereof, that are useful as a single agent or in combination with one or more additional pharmacetical agents, such as, an inhibitor of DPP-IV, a biguanide, an SGLT2 inhibitor, or an alpha-glucosidase inhibitor, in the treatment of, for example, a disorder selected from: a GPR119-receptor-related disorder; a condition ameliorated by increasing a blood incretin level; a metabolic-related disorder; type 2 diabetes; obesity; and complications related thereto.
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Page/Page column 187; 188

(2011/10/31)

Evidence for the role of tetramethylethylenediamine in aqueous negishi cross-coupling: Synthesis of nonproteinogenic phenylalanine derivatives on water
The structure of the alkylzinc-tetramethylethylenediamine (TMEDA) cluster cation 3 has been determined in the gas phase by a combination of tandem mass spectrometry, infrared multiphoton dissociation (IRMPD) spectroscopy, and DFT calculations. Both sets of experimental results establish the existence of a strongly stabilizing interaction of TMEDA with the zinc cation. High-level DFT calculations on the alkylzinc-TMEDA cluster cation 3 allowed the identification of two low energy conformers, each featuring a four-coordinate zinc atom with a bidentate TMEDA ligand, and internal coordination from the carbonyl group of the Boc group to zinc. The experimental IRMPD spectrum is reproduced with an appropriately weighted combination of the IR spectra of the two conformers identified by theory. DFT calculations on the structure of the alkylzinc halide 2 with coordinated TMEDA using the PCM model of water solvent suggest that TMEDA can promote ionization of the zinc-iodine bond in organozinc iodides under aqueous conditions, providing a credible explanation for the role of TMEDA in stabilizing the carbon-zinc bond. Reaction of the serine-derived iodide 1 with aryl iodides "on water", promoted by nano zinc in the presence of PdCl2 (Amphos) 2 (5 mol %) and TMEDA, leads to the formation of protected phenylalanine derivatives 4 in reasonable yields. In the case of ortho-substituted aryl iodides and aryl iodides that are solids at room temperature, conducting the reaction at 65°C gives improved results. In all cases, the product 5 of reductive dimerization of the iodide 1 is also isolated.
Ross, Andrew J.,Dreiocker, Frank,Schae Fer, Mathias,Oomens, Jos,Meijer, Anthony J.H.M.,Pickup, Barry T.,Jackson, Richard F.W.
supporting information; experimental part
p. 1727 - 1734
(2011/05/30)

An eco-sustainable erbium(III) triflate catalyzed formation and cleavage of tert -butyl ethers
An eco-compatible method, which permits the formation or cleavage of tert-butyl ethers of alcohols and phenols, is proposed. The protection step is performed in solvent-free conditions at room temperature using catalytic amount of Er(OTf)3. The catalyst is easily- recovered from the aqueous phase and reused several times without significant loss of activity. The deprotection step developed is also highly eco-friendly since the tert-butyl group is removed very quickly from alcohols and phenols in methanol using MW irradiation-. Georg Thieme Verlag Stuttgart · New York.
Procopio, Antonio,Costanzo, Paola,Curini, Massimo,Nardi, Monica,Oliverio, Manuela,Paonessa, Rosina
experimental part
p. 73 - 78
(2011/03/19)

Cyclic peptide facial amphiphile preprogrammed to self-assemble into bioactive peptide capsules
(Figure Presented) Programmed assembly: A unique supramolecular building block, a cyclic peptide facial amphiphile, predestined to self-assemble into a nanocapsule structure, has been developed (see figure). This general strategy will allow the easy construction of a variety of bioactive nanocapsules.
Chung, Eun Kyung,Lee, Eunji,Lim, Yong-Beom,Lee, Myongsoo
supporting information; experimental part
p. 5305 - 5309
(2010/09/10)

From vesicles to solid spheres: Terminal functional group induced morphology modification
Two similar naphthalimide based organogelators were synthesized. These two compounds can gelate a variety of organic solvents and form interesting morphologies. Transmission and scanning electron microscopy of the xerogels of the two compounds showed vesicle and solid sphere morphologies, respectively, even though their molecular structures are very close. The mechanism of the self-assembly process was investigated by 1H NMR, IR, 2D-NOESY spectra, wide-angle X-ray diffraction and rheological experiments. The study reveals that the cooperation and competition of multiple intra/inter-molecular interactions are the main determining factors for these compounds' self-assembly into vesicles and solid spheres. A single functional group able to determine the formation of vesicles in non-typical amphiphilic system is rarely encountered. Therefore, these results provide further insights into morphology control, especially the formation of vesicles in non-typical amphiphilic systems.
Wang, Qi,Wu, Junchen,Gong, Zuguang,Zou, Ying,Yi, Tao,Huang, Chunhui
scheme or table
p. 2679 - 2684
(2011/11/12)

Synthesis and biological activity of N-substituted aminocarbonyl-1,3- dioxolanes as VLA-4 antagonists
A novel set of compounds with a 1,3-dioxolane ring which acts as a proline bioisostere have been successfully designed as VLA-4 receptor antagonists. Compounds (18e), (28j), and (35g) were shown to have high receptor affinities.
Rehman, Abdul,Soni, Ajay,Naik, Keshav,Nair, Sreeji,Palle, Venkata P.,Dastidar, Sunanda,Ray, Abhijit,Alam,Salman, Mohammad,Cliffe, Ian A.,Sattigeri, Viswajanani
scheme or table
p. 5514 - 5520
(2011/01/12)