- A New Approach to the Synthesis of Diethyl 2,3-Diisobutylsuccinate, a Component of Titanium–Magnesium Catalysts for Propylene Polymerization
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A procedure was developed for preparing 2,3-dialkyl-substituted succinates by condensation of a succinic acid diester with two isobutyraldehyde molecules, followed by esterification and hydrogenation of the sum of dienes. Diethyl 2,3-diisobutylsuccinate of 75%–99% purity was prepared by this procedure in a good yield. The use of the synthesized diethyl 2,3-diisobutylsuccinate as a stereoregulating component of titanium–magnesium catalysts allows synthesis of polypropylene with broad molecular-mass distribution. The catalysts prepared using >95% pure diethyl 2,3-diisobutylsuccinate demonstrated the best characteristics and allowed polypropylene synthesis with high isotacticity index in a high yield.
- Barabanov, A. A.,Bukatov, G. D.,Mainagashev, I. Ya.,Mats’ko, M. A.,Nechepurenko, I. V.,Salakhutdinov, N. F.,Sergeev, S. A.,Volcho, K. P.,Zakharov, V. A.
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p. 715 - 725
(2021/08/13)
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- O-to-S Substitution Enables Dovetailing Conflicting Cyclizability, Polymerizability, and Recyclability: Dithiolactone vs. Dilactone
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Developing chemically recyclable polymers represents a greener alternative to landfill and incineration and offers a closed-loop strategy toward a circular materials economy. However, the synthesis of chemically recyclable polymers is still plagued with certain fundamental limitations, including trade-offs between the monomer's cyclizability and polymerizability, as well as between polymer's depolymerizability and properties. Here we describe the subtle O-to-S substitution, dithiolactone monomers derived from abundant feedstock α-amino acids can demonstrate appealing chemical properties different from those of dilactone, including accelerated ring closure, augmented kinetics polymerizability, high depolymerizability and selectivity, and thus constitute a unique class of polythioester materials exhibiting controlled molecular weight (up to 100.5 kDa), atactic yet high crystallinity, structurally diversity, and chemical recyclability. These polythioesters well addresses the formidable challenges of developing chemically recyclable polymers by having an unusual set of desired properties, including easy-to-make monomer from ubiquitous feedstock, and high polymerizability, crystallinity and precise tunability of physicochemical performance, as well as high depolymerizability and selectivity. Computational studies explain why O-to-S modification of polymer backbone enables dovetailing desirable, but conflicting, performance into one polymer structure.
- Wang, Yanchao,Li, Maosheng,Chen, Jinlong,Tao, Youhua,Wang, Xianhong
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supporting information
p. 22547 - 22553
(2021/09/09)
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- Benzoxazinone-containing 3,5-dimethylisoxazole derivatives as BET bromodomain inhibitors for treatment of castration-resistant prostate cancer
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The bromodomain and extra-terminal proteins (BET) have emerged as promising therapeutic targets for the treatment of castration-resistant prostate cancer (CRPC). We report the design, synthesis and evaluation of a new series of benzoxazinone-containing 3,5-dimethylisoxazole derivatives as selective BET inhibitors. One of the new compounds, (R)-12 (Y02234), binds to BRD4(1) with a Kd value of 110 nM and blocks bromodomain and acetyl lysine interactions with an IC50 value of 100 nM. It also exhibits selectivity for BET over non-BET bromodomain proteins and demonstrates reasonable anti-proliferation and colony formation inhibition effect in prostate cancer cell lines such as 22Rv1 and C4-2B. The BRD4 inhibitor (R)-12 also significantly suppresses the expression of ERG, Myc and AR target gene PSA at the mRNA level in prostate cancer cells. Treatment with (R)-12 significantly suppresses the tumor growth of prostate cancer (TGI = 70%) in a 22Rv1-derived xenograft model. These data suggest that compound (R)-12 is a promising lead compound for the development of a new class of therapeutics for the treatment of CRPC.
- Xue, Xiaoqian,Zhang, Yan,Wang, Chao,Zhang, Maofeng,Xiang, Qiuping,Wang, Junjian,Wang, Anhui,Li, Chenchang,Zhang, Cheng,Zou, Lingjiao,Wang, Rui,Wu, Shuang,Lu, Yongzhi,Chen, Hongwu,Ding, Ke,Li, Guohui,Xu, Yong
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supporting information
p. 542 - 559
(2018/05/24)
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- Enantioselective construction of tetrasubstituted stereogenic carbons through bronsted base catalyzed michael reactions: α′-hydroxy enones as key enoate equivalent
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Catalytic and asymmetric Michael reactions constitute very powerful tools for the construction of new C-C bonds in synthesis, but most of the reports claiming high selectivity are limited to some specific combinations of nucleophile/electrophile compound types, and only few successful methods deal with the generation of all-carbon quaternary stereocenters. A contribution to solve this gap is presented here based on chiral bifunctional Bronsted base (BB) catalysis and the use of α′-oxy enones as enabling Michael acceptors with ambivalent H-bond acceptor/donor character, a yet unreported design element for bidentate enoate equivalents. It is found that the Michael addition of a range of enolizable carbonyl compounds that have previously demonstrated challenging (i.e., α-substituted 2-oxindoles, cyanoesters, oxazolones, thiazolones, and azlactones) to α′-oxy enones can afford the corresponding tetrasubstituted carbon stereocenters in high diastereo- and enantioselectivity in the presence of standard BB catalysts. Experiments show that the α′-oxy ketone moiety plays a key role in the above realizations, as parallel reactions under identical conditions but using the parent α,β-unsaturated ketones or esters instead proceed sluggish and/or with poor stereoselectivity. A series of trivial chemical manipulations of the ketol moiety in adducts can produce the corresponding carboxy, aldehyde, and ketone compounds under very mild conditions, giving access to a variety of enantioenriched densely functionalized building blocks containing a fully substituted carbon stereocenter. A computational investigation to rationalize the mode of substrate activation and the reaction stereochemistry is also provided, and the proposed models are compared with related systems in the literature.
- Badiola, Eider,Fiser, Bla,Gmez-Bengoa, Enrique,Mielgo, Antonia,Olaizola, Iurre,Urruzuno, Iaki,Garca, Jess M.,Odriozola, Jos M.,Razkin, Jess,Oiarbide, Mikel,Palomo, Claudio
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supporting information
p. 17869 - 17881
(2015/02/19)
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- Synthesis of enantiomerically enriched-bromonitriles from amino acids
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Two methods were investigated for the preparation of six chiral-bromonitriles with different optic purities. The nitrous deamination of amino acids gives-bromoacids, which react with chlorosulfonyl isocyanate followed by triethylamine to afford-bromonitriles with moderate enantiomeric excess. However, the dehydration of corresponding-bromoamids using thionyl chloride gives-bromonitriles with good enantiomeric excess up to 94%. The use of phosphoryl chloride instead of thionyl chloride results in more than 30% racemization as determined by high-performance liquid chromatograpic analysis.
- Tka, Najeh,Kraem, Jamil,Hassine, Bechir Ben
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p. 735 - 743
(2013/01/15)
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- THIAZOL-COMPOUNDS AS 11-BETA-HYDROXYSTEROID DEHYDROGENASE TYPE 1 INHIBITORS
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The present invention relates to compounds with the formula (I), wherein R1, R2, R3, X, and Y are as defined herein, and also to pharmaceutical compositions comprising the compounds, as well as to the use of the compounds in medicine and for the preparation of a medicament which acts on the human 11-β-hydroxysteroid dehydrogenase type 1 enzyme.
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Page/Page column 150-151
(2008/06/13)
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- alpha-AMINO ACID PHENYL ESTER DERIVATIVES
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The present invention relates to alpha-amino acid phenyl ester derivatives having general formula (I) wherein R1 is (C1-3)alkyloxy; R2 is (C1-3)alkyl, (C1-3)alkyloxy or (C2-3)alkenyl; R3 is hydrogen, (C1-3)alkyl, (C1-3)alkyloxy or (C2-3)alkenyl; R4 is (C1-6)alkyl; R5 and R6 are independently (C1-6)alkyl, (C2-6)alkenyl, (C2-6)alkynyl or aralkyl, each of which may be optionally substituted with (C1-3)alkyloxy, (C1-3)alkyloxycarbonyl, cyano or NR7R8; R7 and R8 are independently (C1-6)alkyl; or a pharmaceutically acceptable salt thereof. The invention also relates to pharmaceutical compositions comprising said derivatives, and to the use of these alpha-amino acid phenyl ester derivatives as hypnotics for the induction and maintenance of general anaesthesia.
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- Matrix metalloproteinase inhibitors
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A compound of formula (I), wherein W is —NHOH or —OH, R1is either free or protected hydroxymethyl or mercaptomethyl or derivatives thereof, R2is free or protected hydroxy, R3and R4is an organic group, R5/s
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- CARBOSTYRIL DERIVATIVES AS MATRIX METALLOPROTEINASES INHIBITORS
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This invention provides a carbostyril derivative of the formula (1): STR1 where R 1, R 2, R 3, R 4, R 5, R 6 and n are as defined, or its salt. This carbostyril derivative or its salt possess an excellent matrix metalloproteinases inhibitory action.
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- Bombesin analogs
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Agonists and Antagonist of bombesin are derivatives of naturally occurring bombesin possessing a methyl sulfide or a methyl amide bond connecting the two amino acids on the carboxy terminal end. Agonist and antagonist activities are confirmed using conventional competitive binding and biochemical assays as well as conventional physiological tests and the use of these derivatives in a variety of conditions. Use of these peptides include stimulating or antagonizing growth of tissues, especially lung, and a means for effecting treatment for digestional disorders. Treatment comprises administering to a patient in need thereof, an effective amount of a bombesin analog.
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- Peptide derivatives useful as antagonists of bombesin and gastrin-releasing peptide
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A method for controlling the growth of tumor tissues, especially small cell lung and prostatic carcinomas, and gastric acid secretion, causative and symptomatic of, peptic (esophageal, gastric, and duodenal) ulcers. Treatment comprises administering to a patient in need thereof, an effective amount of a bombesin/GRP type inhibitor. ψAntagonists of bombesin/GRP which are derivatives of naturally occurring bombesin/GRP possessing a thiomethylene or methylene sulfoxide bond connecting the two amino acids on the carboxy terminal end is modified are described. The antagonism is confirmed using conventional competitive binding and biochemical assays as well as conventional physiological tests and the use of these derivatives in a variety of conditions in which bombesin/GRP is implicated is also described.ψ
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- Phosphoramidate peptide inhibitors of human skin fibroblast collagenase
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An extensive series of N-(monoethylphosphoryl)peptides was synthesized and their inhibition of purified human skin fibroblast collagenase examined. At the cleavage site S1 all reported compounds have the (EtO)(OK)P(O) group and the peptide side chain extended toward the C-terminal end (up to P5') of the substrate sequence. These phosphoramidates with a tetrahedrally hybridized phosphorus atom are thought to be transition state analogue inhibitors. They exhibited fair inhibitory potency against this vertebrate collagenase having K(i) values in the micromolar range. The most potent of these, (EtO)(OK)P(O)-Ile-TrpNHCH3 (68), inhibits with a K(i) value of 1.5 μM and is nearly 100 times stronger than (EtO)(OK)P(O)-Ile-Ala-GlyOK (51) (K(i) of 140 μM), which has the sequence matching that of the α1(I) chain of collagen in P1', P2', P3' after the cleavage site. Several compounds were prepared in an attempt to identify the nature of the S2', S3', and S4' binding sites. Alanine at the P2' position was replaced by leucine, phenylalanine, tryptophan, or tyrosine derivatives, resulting in K(i) values in a significantly lower range, 1.0-40 μM, compared to 51. No upper size limitation or specificity has been found at this position, yet similar replacements at the P3' position, which is occupied naturally by a glycine residue, gave weaker inhibitors: (EtO)(OK)P(O)-Ile-Tyr(OBzl)-PheOK (57) had a K(i) of 120 μM. Hexapeptide derivatives had weaker activities in the 270 μM-2 mM range. All inhibitors were evaluated by using the synthetic thio peptolide spectrophotometric assay.
- Kortylewicz,Galardy
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p. 263 - 273
(2007/10/02)
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- Novel thiopeptolide substrates for vertebrate collagenase
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The disclosure relates to novel synthetic thiopeptolide substrates having high activity for the enzyme collagenase. These substrates have the following amino acid sequences: wherein R=H or N-protecting group, X=Leu, Ile, Phe, Val, Gln, Ala, Y=Leu, Ile, Phe, Val, Ala, Z=Leu, Ile, Phe, Val, Gln, Ala, and R1 =terminal amide, carboxyl or ester group.
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- Modified Di- and Tripeptides of the C-Terminal Portion of Oxytocin and Vasopressin as Possible Cognition Activation Agents
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A number of peptides and modified peptides were synthesized and studied for their ability to reverse electroconvulsive shock-induced amnesia in rodents.A few of these peptides were selected for secondary evaluation in tests of short-term memory in rats and aged rhesus monkeys.A number of the peptides and modified peptides were active in the amnesia reversal test.In selected secondary tests, however, the chosen compounds failed to show significant activity in enhancing memory.New methods for preparing methyleneamino and methyleneoxy isosters of peptides are reportrd.Other modified peptides also included methylenethio, methylenesulfonyl, and ethylene isosteres in place of the normal peptide amide bond.
- Nicolaides, E. D.,Tinney, F. J.,Kaltenbronn, J. S.,Repine, J. T.,DeJohn, D. A.,et al.
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p. 959 - 971
(2007/10/02)
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