- Molecular engineering and synthesis of novel metal-free organic sensitizers with D-π-A-π-A architecture for DSSC applications: The effect of the anchoring group
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Herein, we report the design and synthesis of two metal-free organic sensitizers (MR-5 & MR-6) with a D-π-A-π-A architecture based on a trimethoxy benzene donor core carrying two different withdrawing/anchoring groups including cyanoacetic acid and rhodan
- Elmorsy, Mohamed R.,Su, Rui,Fadda, Ahmed A.,Etman,Tawfik, Eman H.,El-Shafei, Ahmed
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- Enabling Cysteine-Free Native Chemical Ligation at Challenging Junctions with a Ligation Auxiliary Capable of Base Catalysis
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Ligation auxiliaries are used in chemical protein synthesis to extend the scope of native chemical ligation (NCL) beyond cysteine. However, auxiliary-mediated ligations at sterically demanding junctions have been difficult. Often the thioester intermediate formed in the thiol exchange step of NCL accumulates because the subsequent S→N acyl transfer is extremely slow. Here we introduce the 2-mercapto-2-(pyridin-2-yl)ethyl (MPyE) group as the first auxiliary designed to aid the ligation reaction by catalysis. Notably, the MPyE auxiliary provides useful rates even for junctions containing proline or a β-branched amino acid. Quantum chemical calculations suggest that the pyridine nitrogen acts as an intramolecular base in a rate-determining proton transfer step. The auxiliary is prepared in two steps and conveniently introduced by reductive alkylation. Auxiliary cleavage is induced upon treatment with TCEP/morpholine in presence of a MnII complex as radical starter. The synthesis of a de novo designed 99mer peptide and an 80 aa long MUC1 peptide demonstrates the usefulness of the MPyE auxiliary.
- Fuchs, Olaf,Hanebrink, Hendrik,Reimann, Marc,Seitz, Oliver,Trunschke, Sebastian
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supporting information
p. 19483 - 19490
(2021/08/09)
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- An efficient approach for the synthesis of novel methyl sulfones in acetic acid medium and evaluation of antimicrobial activity
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A series of nine methyl sulphones (3a-3i) starting from the aldehydes (1a-1i) were synthesized in two consecutive steps. In the first step, preparation of allyl alcohols (2a-2i) from their corresponding aldehydes by the reaction of sodium borohydride in methanol at room temperature is reported. Finally, methyl sulphones are synthesized by condensing sodium methyl sulfinates with allyl alcohols in the presence of BF3.Et2O in acetic acid medium at room temperature for about 2-3 h. The reaction conditions are simple, yields are high (85%-95%), and the products were obtained with good purity. All the synthesized compounds were characterized by their 1H, 13C NMR, and mass spectral analysis. All the title compounds were screened for antimicrobial activity. Among the compounds tested, the compound 3f has inhibited both Gram positive and Gram negative bacteria effectively and compound 3i has shown potent antifungal activity. These promising components may help to develop more potent drugs in the near future for the treatment of bacterial and fungal infections.
- Bollikolla, Hari Babu,Dasireddy, Chandra Rao,Kotra, Vijay,Ravi Kumar, Gollapudi,Varala, Ravi
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p. 1386 - 1394
(2020/11/20)
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- On the Necessity of Nucleobase Protection for 2-Thiouracil for Fmoc-Based Pseudo-Complementary Peptide Nucleic Acid Oligomer Synthesis
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A selection of benzyl-based protecting groups for thiouracil (SU) for the synthesis of pseudo-complementary peptide nucleic acid (PNA) has been evaluated. The 4-methoxybenzyl-protecting group that has found use for SU during Boc-based oligomerization is also suitable for Fmoc-based oligomerization. Furthermore, it is demonstrated that SU protection is unnecessary for the successful synthesis of thiouracil-containing PNA. The new 2-thiothymine (ST) PNA monomer has also been prepared and incorporated into an oligomer and its binding to complementary PNA evaluated.
- Hudson, Robert H.E.,Heidari, Ali,Martin-Chan, Timothy,Park, Gyeongsu,Wisner, James A.
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p. 13252 - 13261
(2019/11/16)
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- A Tripeptide Approach to the Solid-Phase Synthesis of Peptide Thioacids and N-Glycopeptides
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A general and robust method for the incorporation of aspartates with a thioacid side chain into peptides has been developed. Pseudoproline tripeptides served as building blocks for the efficient fluorenylmethyloxycarbonyl (Fmoc) solid-phase synthesis of t
- Sch?we, Markus Julian,Keiper, Odin,Unverzagt, Carlo,Wittmann, Valentin
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supporting information
p. 15759 - 15764
(2019/11/19)
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- IRIDIUM-BASED CATALYSTS FOR HIGHLY EFFICIENT DEHYDROGENATION AND HYDROGENATION REACTIONS IN AQUEOUS SOLUTION AND APPLICATIONS THEREOF
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A series of iridium-based catalysts for dehydrogenation of formic acid, and hydrogenation using formic acid as the hydrogen source, and the process using the catalyst(s) to produce hydrogen gas from formic acid solution, or to reduce aldehydes using formic acid, are disclosed and claimed. More specifically, the present invention relates to a group of pentamethylcyclopentadienyl (Cp*) iridium complexes with different Ν,Ν-bidentate ligands that catalyze dehydrogenation from formic acid, and chemo-selective hydrogenation of aldehydes, in the aqueous solution system in a highly efficient, and long life-time manner.
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Page/Page column 13-14
(2018/11/22)
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- Dynamic and Responsive DNA-like Polymers
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The synthesis of thiolactone monomers that mimic natural nucleosides and engage in robust ring opening polymerizations (ROP) is herein described. As each repeat unit contains a thioester functional group, dynamic rearrangement of the polymer is feasible v
- Mavila, Sudheendran,Worrell, Brady T.,Culver, Heidi R.,Goldman, Trevor M.,Wang, Chen,Lim, Chern-Hooi,Domaille, Dylan W.,Pattanayak, Sankha,McBride, Matthew K.,Musgrave, Charles B.,Bowman, Christopher N.
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supporting information
p. 13594 - 13598
(2018/10/24)
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- Novel indole and triazole based hybrid molecules exhibit potent anti-adipogenic and antidyslipidemic activity by activating Wnt3a/β-catenin pathway
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Obesity and dyslipidemia is the two facet of metabolic syndrome, which needs further attention. Recent studies indicate triazole and indole derivatives have remarkable anti-obesity/antidyslipidemic activity. To harness the above-mentioned potential, a series of novel triazole clubbed indole derivatives were prepared using click chemistry and evaluated for anti-adipogenic activity. Based on the structure-activity relationship, essential functional groups which potentiate anti-adipogenic activity were identified. The lead compound 13m exhibited potent anti-adipogenic activity compared to its parent compounds with the IC-50 value of 1.67 μM. Further evaluation of anti-adipogenic activity was conducted in different cell lines such as C3H10T1/2 and hMSC with positive result. The anti-adipogenic effect of compound 13m was most prominent in the early phase of adipogenesis, which is driven by the G1 to S phase cell cycle arrest during mitotic clonal expansion. The mechanistic study suggests that compound 13m exhibit anti-adipogenic property by activating Wnt3a/β-catenin pathway, a known suppressor of key adipogenic genes PPARγ and C/EBPα. It is noteworthy that the compound 13m also reduced serum triglyceride, LDL and total cholesterol in Syrian Golden hamster model of dyslipidemia. The anti-adipogenic activity of compound 13m can also be correlated with decreased expression of PPARγ and increased expression of β-catenin in epididymal white adipose tissue (eWAT) in vivo. The compound 13m also increased the expression of genes involved in reverse cholesterol transport (RCT) such as PPARα and LXR1α indicating another mechanism by which compound 13m ameliorates dyslipidemia in Syrian Golden hamster model. Overall this study provides a unique perspective into the anti-adipogenic/antidyslipidemic property of triazole and indole hybrids molecules with further scope to increase the anti-adipogenic potency for therapeutic intervention of obesity and metabolic syndrome.
- Rajan, Sujith,Puri, Surendra,Kumar, Durgesh,Babu, Madala Hari,Shankar, Kripa,Varshney, Salil,Srivastava, Ankita,Gupta, Abhishek,Reddy, M. Sridhar,Gaikwad, Anil N.
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supporting information
p. 1345 - 1360
(2017/11/20)
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- Iridium-catalyzed highly efficient chemoselective reduction of aldehydes in water using formic acid as the hydrogen source
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A water-soluble highly efficient iridium catalyst is developed for the chemoselective reduction of aldehydes to alcohols in water. The reduction uses formic acid as the traceless reducing agent and water as a solvent. It can be carried out in air without the need for inert atmosphere protection. The products can be purified by simple extraction without any column chromatography. The catalyst loading can be as low as 0.005 mol% and the turn-over frequency (TOF) is as high as 73 800 mol mol-1 h-1. A wide variety of functional groups, such as electron-rich or deficient (hetero)arenes and alkenes, alkyloxy groups, halogens, phenols, ketones, esters, carboxylic acids, cyano, and nitro groups, are all well tolerated, indicating excellent chemoselectivity.
- Yang, Zhanhui,Zhu, Zhongpeng,Luo, Renshi,Qiu, Xiang,Liu, Ji-Tian,Yang, Jing-Kui,Tang, Weiping
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supporting information
p. 3296 - 3301
(2017/07/28)
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- Postsynthetic modification of bacterial peptidoglycan using bioorthogonal n-acetylcysteamine analogs and peptidoglycan o-acetyltransferase B
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Bacteria have the natural ability to install protective postsynthetic modifications onto its bacterial peptidoglycan (PG), the coat woven into bacterial cell wall. Peptidoglycan O-acetyltransferase B (PatB) catalyzes the O-acetylation of PG in Gram (-) bacteria, which AIDS in bacterial survival, as it prevents autolysins such as lysozyme from cleaving the PG. We explored the mechanistic details of PatB's acetylation function and determined that PatB has substrate specificity for bioorthgonal short N-acetyl cysteamine (SNAc) donors. A variety of functionality including azides and alkynes were installed on tri-N-acetylglucosamine (NAG)3, a PG mimic, as well as PG isolated from various Gram (+) and Gram (-) bacterial species. The bioorthogonal modifications protect the isolated PG against lysozyme degradation in vitro. We further demonstrate that this postsynthetic modification of PG can be extended to use click chemistry to fluorescently label the mature PG in whole bacterial cells of Bacillus subtilis. Modifying PG postsynthetically can aid in the development of antibiotics and immune modulators by expanding the understanding of how PG is processed by lytic enzymes.
- Wang, Yiben,Lazor, Klare M.,DeMeester, Kristen E.,Liang, Hai,Heiss, Tyler K.,Grimes, Catherine L.
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supporting information
p. 13596 - 13599
(2017/11/06)
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- Unprecedented alkylation of silicon enolates with alcohols via carbenium ion formations catalyzed by tin hydroxide-embedded montmorillonite
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The solid acid, tin hydroxide-embedded montmorillonite, catalyzes the unprecedented alkylation of various silicon enolates with primary, secondary and tertiary benzylic alcohols as well as secondary allylic alcohols. The acid catalysis of Sn-Mont was not only higher than that of the other ion-exchanged montmorillonites (M-Mont; M?=?H, Ti, Fe and Al), but also higher than that of the typical homogeneous acid catalysts such as BF3·OEt2, TMSOTf and TfOH.
- Tandiary, Michael Andreas,Asano, Masashi,Hattori, Taiki,Takehira, Satoshi,Masui, Yoichi,Onaka, Makoto
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supporting information
p. 1925 - 1928
(2017/04/27)
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- NOVEL COMPOUND, AGENT AND NK3 RECEPTOR ANTAGONIST
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PROBLEM TO BE SOLVED: To provide a NK3 receptor antagonist that inhibits the propagation of animals without adverse effect on an ecological system. SOLUTION: The present invention provides a compound represented by formula (I') (R1 is H, a hydroxy group or the like; R2 is a hydroxy group, a mercapto group or the like; R3 is a phenyl group or naphthyl group). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0062; 0063
(2017/08/02)
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- Thiazolidine-Protected β-Thiol Asparagine: Applications in One-Pot Ligation-Desulfurization Chemistry
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The synthesis of a β-thiol asparagine derivative bearing a novel (2,4,6-trimethoxyphenyl)thiazolidine protecting group is described. The efficient incorporation of the amino acid into the N-termini of peptides is demonstrated as well as the utility of the
- Sayers, Jessica,Thompson, Robert E.,Perry, Kristen J.,Malins, Lara R.,Payne, Richard J.
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supporting information
p. 4902 - 4905
(2015/10/12)
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- Development of a novel benzyl mercaptan as a recyclable odorless substitute of hydrogen sulfide
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2,4,6-Trimethoxybenzyl mercaptan (4) was developed as an odorless substitute of hydrogen sulfide to afford β-mercapto carbonyl compounds in a Michael addition and to convert alkyl bromides into alkanethiols. Detrimethoxybenzylation of the Michael adducts prepared from 4 and α,β-unsaturated esters or ketones was facilely carried out by treatment with a solvent mixture of trifluoroacetic acid and toluene to give β-mercapto carbonyl compounds. Successive alkaline hydrolysis of 2,4,6-trimethoxybenzyl isothiouronium salt, which was obtained as a side product, regenerated 4 accompanying disulfide 8 in good yield. The disulfide 8 was also converted into 4 by reduction with LiAlH4. A similar protocol was applicable to the synthesis of alkanethiols using the S N2 reaction of alkyl bromides. Our method could be complementary to the classical method of using malodorous benzyl mercaptan as a nucleophile and Birch reduction for debenzylation. Georg Thieme Verlag Stuttgart.
- Matoba, Manabu,Kajimoto, Tetsuya,Node, Manabu
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p. 1930 - 1934
(2008/03/27)
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- On water and in air: Fast and highly chemoselective transfer hydrogenation of aldehydes with iridium catalysts
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(Chemical Equation Presented) Water as solvent: A fast, selective, and high-yielding transfer hydrogenation of a wide range of aldehydes is achieved using IrIII catalysts containing simple ethylene-diamine (en) ligands (see scheme; Ts = p-toluenesulfonyl, TOF = turnover frequency). This procedure is suitable for aldehydes with a wide range of functional groups.
- Wu, Xiaofeng,Liu, Jianke,Li, Xiaohong,Zanotti-Gerosa, Antonio,Hancock, Fred,Vinci, Daniele,Ruan, Jiwu,Xiao, Jianliang
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p. 6718 - 6722
(2007/10/03)
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- Oxidations of benzyl and phenethyl phenyl sulfides. Implications for the mechanism of the microsomal and biomimetic oxidation of sulfides
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The study of the oxidation of 4-methoxyphenethyl phenyl sulfide and 3,4-dimethoxyphenethyl phenyl sulfide with potassium 12-tungstocobalt(III)ate [Co(III)W] suggests that in the radical cations of 3,4,5-(MeO)3PhCH2SPh (4) and 2,4,6(MeO)3PhCH2SPh (5) the positive charge is not localized on the sulfur atom, but in the benzylic aromatic ring. Nevertheless, in the biomimetic and microsomal oxidation of 4 and 5 the products observed are exclusively sulfoxides and sulfones, which appears in contrast with a mechanism involving the formation of an intermediate sulfide radical cation followed by a fast oxygen rebound. A direct oxygen transfer mechanism seems most likely.
- Baciocchi, Enrico,Lanzalunga, Osvaldo,Pirozzi, Bruno
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p. 12287 - 12298
(2007/10/03)
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