- Second-coordination sphere effects on the reactivities of Hoveyda-Grubbs-type catalysts: A ligand exchange study using phenolic moiety-functionalized ligands
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The Hoveyda-Grubbs (HG) second-generation catalyst (HG-II), a Ru complex with a 2-isopropoxybenzylidene ligand, is extensively used for olefin metathesis, the rearrangement of carbon-carbon double bonds. A well-known strategy to control its complex reactivity is to modify the phenyl ring in the ligand, thereby directly influencing the coordination of the phenolic oxygen to the metal center. We, herein, report that a functional group attached to the phenolic moiety in the 2-alkoxybenzylidene ligand can indirectly affect the reactivities of HG-type complexes. In this work, the ligand exchange reactions between HG-II and phenolic moiety-modified 2-alkoxybenzylidene ligands are useful for evaluating the structural effects of the ligands. Specifically, an ethylene amide or an ester group at the terminal phenolic moiety in the benzylidene ligand was found to influence the relative stabilities of HG-type complexes compared to that of the HG-II complex. The structural analyses proved that the observed effects of the functional groups on the complex stabilities originate from the interactions with a chlorido ligand in HG-type complexes without changes in coordination fashions at the metal centers. It was found that the outer-sphere interactions also influence the catalytic activities of HG-type complexes, namely, the properties of HG-type complexes can be controlled by outer-sphere structural factors toward the metal center (i.e., "the second-coordination sphere effect"). In the design of functionalized HG-type complexes, the outer-sphere structural effects need to be considered in addition to the optimization of the metal coordination site.
- Akiyama, Naoki,Goshima, Kenta,Hirota, Shun,Jatmika, Catur,Matsuo, Takashi,Wakabayashi, Kazumo
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supporting information
p. 11618 - 11627
(2020/09/09)
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- 4-anilinoquinazoline derivative and albumin conjugates thereof
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a pharmaceutical composition for preventing, treating, or ameliorating one or more symptoms of a malignant tumor associated with EGFR mutation and/or K-RAS mutation is provided. The pharmaceutical composition includes a 4-anilinoquinazoline derivative having a formula (I) where A is iodine when m is 1 and n is zero, or A is albumin when m is an integral ranging from 1 to 7 and n is 1.
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Page/Page column 12
(2019/04/26)
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- Isopropenyl acetate: A cheap and general acylating agent of alcohols under metal-free conditions
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Functionalized primary, secondary and tertiary alcohols are efficiently acetylated by isopropenyl acetate and catalytic p-TsOH.
- Temperini, Andrea,Minuti, Lucio,Morini, Tommaso,Rosati, Ornelio,Piazzolla, Francesca
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p. 4051 - 4053
(2017/09/27)
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- Synthesis and biological assay of erlotinib analogues and BSA-conjugated erlotinib analogue
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A series of erlotinib analogues that have structural modification at 6,7-alkoxyl positions is efficiently synthesized. The in vitro anti-tumor activity of synthesized compounds is studied in two non-small cell lung cancer (NSCLC) cell lines (A549 and H1975). Among the synthesized compounds, the iodo compound 6 (ETN-6) exhibits higher anti-cancer activity compared to erlotinib. An efficient method is developed for the conjugation of erlotinib analogue-4, alcohol compound, with protein, bovine serum albumin (BSA), via succinic acid linker. The in vitro anti-tumor activity of the protein attached erlotinib analogue, 8 (ETN-4-Suc-BSA), showed stronger inhibitory activity in both A549 and H1975 NSCLC cell lines.
- Boobalan, Ramalingam,Liu, Kuang-Kai,Chao, Jui-I.,Chen, Chinpiao
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supporting information
p. 1784 - 1788
(2017/04/04)
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- Acetylcholine-like and trimethylglycine-like PTA (1,3,5-Triaza-7- phosphaadamantane) derivatives for the development of innovative Ru- and Pt-based therapeutic agents
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The PTA N-alkyl derivatives (PTAC2H4OCOMe)X (1X: 1a, X = Br; 1b, X = I; 1c, X = PF6; 1d, X = BPh4), (PTACH 2COOEt)X (2X: 2a, X = Br; 2b, X = Cl; 2c, X = PF6), and (PTACH2CH2COOEt)X (3X: 3a, X = Br; 3c, X = PF 6), presenting all the functional groups of the natural cationic compounds acetylcholine or trimethylglycine combined with a P-donor site suitable for metal ion coordination, were prepared and characterized by NMR, ESI-MS, and elemental analysis. The X-ray crystal structures of 1d and 2c were determined. Ligands 1c, 2b, and 3c were coordinated to Pt(II) and Ru(II) to give the cationic complexes cis-[PtCl2(L)2]X2 and [RuCpCl(PPh3)(L)]X (L = 1, 2, 3, X = Cl or PF6) designed with a structure targeted for anticancer activity. The X-ray crystal structure of [CpRu(PPh3)(PTAC2H4OCOMe)Cl]PF6 (1cRu) was determined. The antiproliferative activity of the ligands and the complexes was evaluated on three human cancer cell lines.
- Ferretti, Valeria,Fogagnolo, Marco,Marchi, Andrea,Marvelli, Lorenza,Sforza, Fabio,Bergamini, Paola
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p. 4881 - 4890
(2014/06/09)
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- Synthesis of naphthyridone derivatives containing 8-alkoxyimino-1,6- dizaspiro[3.4]octane scaffolds
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The synthesis of naphthyridone derivatives containing 8-alkoxyimino-1,6- dizaspiro[3.4]octane scaffolds, the position isomers of the side chain at the C-7 position of Zabofloxacin, has been achieved in eight steps from tert-butyl 3-cyano-4-oxopyrrolidine-1-carboxylate. The possible reaction mechanisms were also proposed. The key spirocyclic carbamate esters, which could be prepared using a modified Hofmann rearrangement strategy, were condensed with naphthyridone nuclei, and the resulting condensates were easily cleaved by TMSI and subsequently cyclized in the presence of K2CO3. Moreover, additional N-methylation derivatives were also obtained using the synthetic sequence.
- Feng, Lian-Shun,Liu, Ming-Liang,Wang, Shuo,Chai, Yun,Lv, Kai,Shan, Guang-Zhi,Cao, Jue,Li, Su-Jie,Guo, Hui-Yuan
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experimental part
p. 8264 - 8270
(2011/11/07)
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- Synthesis and biological evaluation of orally active prodrugs of indomethacin
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Synthesis and biological evaluation of orally active prodrugs (1a-d) of indomethacin are described. Prodrugs 1a-c showed a similar degree of anti-inflammatory activity, and prodrug 1d was found to be less potent than the parent drug indomethacin (1). Ulcer index (UI) data indicated that 1a (UI = 19), 1c (UI = 0), and 1d (UI = 0) were substantially less ulcerogenic and 1b (UI = 62) was more ulcerogenic than parent drug 1 (UI = 47). These prodrugs demonstrated good stability at acidic and basic pH and found to be more lipophilic than parent drug compound 1, indicated by partition coefficients measured in octanol-buffer system at pH 7.4 and 3.0. On the basis of in vivo studies, 1a and 1c compounds were selected for metabolic stability in rat liver microsome (RLM) and rat plasma (RP), and both were found to be enzymatically labile. Prodrugs 1a and 1c emerged as potent anti-inflammatory agents with a lesser potential for ulcer than the parent drug indomethacin.
- Bandgar, Babasaheb P.,Sarangdhar, Rajendra Janardan,Viswakarma, Santosh,Ahamed, Fakrudeen Ali
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experimental part
p. 1191 - 1201
(2011/04/26)
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- Synthesis, characterization, and biological evaluation of novel diclofenac prodrugs
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Diclofenac ester pro drugs (4, 5, 6) were synthesized and evaluated in vitro and in vivo for their potential use for oral delivery, with the aim of obtaining enzymatically labile and less ulceration drugs than the parent drug diclofenac sodium (1a). Prodrugs 4, 5, 6 were found to be potent anti-inflammatory drugs with less ulcerogenic potential than the parent diclofenac sodium. Prodrugs 4, 5, 6 rapidly underwent enzymatic hydrolysis to release the parent drug diclofenac in 30-60 min in rat liver microsomes (RLM) and rat plasma (RP). Prodrugs were found to be more lipophilic when the partition coefficient was measured in 1-octanol and buffer system at pH 7.4 and 3.0. Diclofenac prodrugs 4, 5, 6 were found to be crystalline in nature (analyzed by PXRD). Prodrug 4 was found to be a superior candidate for the treatment of chronic inflammatory diseases.
- Bandgar, Babasaheb P.,Sarangdhar, Rajendra Janardan,Ahamed, Fakrudeen Ali,Viswakarma, Santosh
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experimental part
p. 1202 - 1210
(2011/04/26)
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- Diarylselenide compounds and their use in human or veterinary medicine and in cosmetics
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The invention concerns novel diarylselenide compounds corresponding to formula (I): and the use thereof in pharmaceutical compositions in human or veterinary medicine (in the treatment of dermatological, rheumatic, cardiovascular and ophthalmologic pathologies in particular), or in cosmetic compositions.
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Page/Page column 15
(2010/02/15)
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- Pyrithione compound and microcapsule using the same
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A compound represented by formula (I); a multifunctional isocyanate composition, containing an adduct formed by treating the compound represented by formula (I) with a compound represented by formula (II); and a microcapsule using the multifunctional isocyanate composition: wherein, in formula (I), R1 represents -L1-X1 or X1; R2 represents a hydrogen atom or -L2-X2; L1 and L2 each independently represent a divalent linking group; X1 and X2 each independently represent a nucleophilic substituent; n represents an integer of 1 to 4; and when n is 2 or more, R1s may be the same or different; and [in-line-formulae]R3—(NCO)m??Formula (II) [/in-line-formulae]wherein, in formula (II), R3 represents an arbitrary m-valent linking group; and m represents an integer of 2 or above.
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Page/Page column 9
(2010/02/14)
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- Effect of Crown Ethers on Bromination of 2-Methyl-1,3-dioxacycloalkanes with N-Bromosuccinimide
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Crown ethers exert a pronounced catalytic effect on bromination of 2-methyl-1,3-dioxacycloalkanes with N-bromosuccinimide and increase the yield of 2-bromomethyl derivatives.
- Kotlyar,Pluzhnik-Gladyr',Zlotskii
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p. 283 - 284
(2007/10/03)
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- Bromination of 1,3-dioxolanes by molecular bromine
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Bromination of alkyl-substituted 1,3-dioxolanes by molecular bromide in carbon tetrachloride occurs regioselectively with preservation of heterocycle and leads to formation of 2-(α-bromoalkyl)-1,3-dioxolane.
- Vershinin,Makayeva,Zorina,Zorin,Rahmankulov
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p. 1147 - 1149
(2007/10/03)
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- Effects of Volume and Surface Property in Hydrolysis by Acetylcholinesterase. The Trimethyl Site
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β-Substituted ethyl acetates, XCH2CH2OCOCH3, have been prepared, and their hydrolysis by acetylcholinesterase has been studied.Log of enzymic reactivity, normalized for intrinsic reactivity in hydrolysis by hydroxide, log(kcat/Km)n, rises linearly with increasing refraction volume, MR (or RD25), for substrates with β-X = H, Cl, Br, CH3CH2, (CH3)2CH, (CH3)2S+, (CH3)3N+, and (CH3)3C.Larger substituents may by accommodated, (CH3)3Si and (CH3CH2)3N+, with no further increase in rate.Substrates with β-substituents CH3S, CH3S(O), (CH3)3N+(OH), and CH3S(O2) are less reactive than consistent with the relation with MR by factors of 5-40, indicating that hydrophobic surface and desolvation of the substrate-enzyme interface may be necessary for maximum reactivity correlated with MR.Values of log (kcat/Km)n for substrates with β-substituents X = CH3S, Cl, Br, CH3CH2, (CH3)2CH, (CH3)3C, and (CH3)3Si rise linearly with increasing hydrophobicity, ?, but reactivity of substrates with X = (CH3)3N+ and (CH3)2S+ are more reactive than consistent with a relation to ? by factors of 300 and 40 and with X = CH3S(O2), CH3S(O), and (CH3)2N+(OH), by factors of 7-100.Reactivity appears related to (i) volume of the β-substituent and its fit in its subsite, which is trimethyl rather than anionic, and (ii) the hydrophobicity of its surface.
- Cohen, Saul G.,Elkind, Jerome L.,Chishti, S. Bano,Giner, Jose-L. P.,Reese, Heide,Cohen, Jonathan B.
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p. 1643 - 1647
(2007/10/02)
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- Reactions of 1,3-Dioxacyclanes with Acid Halides. A New Synthesis for ω-Halohydrine Esters
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Reaction of 1,3-dioxolanes and 1,3-dioxanes with aliphatic acid chlorides and bromides yields 2- or 3-halohydrine esters. - Keywords: 1,3-Dioxolanes and 1,3-dioxanes, ring opening of
- Kwiatkowski, Stefan,Wolinski, Andrzej
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p. 869 - 872
(2007/10/02)
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- CHARACTER OF THE PRODUCTS OF BROMINATION OF 1,3-DIOXACYCLANES WITH N-BROMOSUCCINIMIDE
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The dependence of the character and composition of the products of the reaction of equimolar amounts of N-bromosuccinimide and 1,3-dioxacyclanes on the ring size and the character of the substituent in the 2 position of the 1,3-dioxacyclane ring was examined.Reasons for the primary formation of bromination products of different types for five-, six-, and seven-membered cyclic acetals are proposed.
- Kotlyar, S. A.,Kamalov, G. L.
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p. 118 - 119
(2007/10/02)
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