- Formylation of electron-rich aromatic rings mediated by dichloromethyl methyl ether and TiCl4: Scope and limitations
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Here the aromatic formylation mediated by TiCl4 and dichloromethyl methyl ether previously described by our group has been explored for a wide range of aromatic rings, including phenols, methoxy- and methylbenzenes, as an excellent way to produce aromatic aldehydes. Here we determine that the regioselectivity of this process is highly promoted by the coordination between the atoms present in the aromatic moiety and those in the metal core.
- Ramos-Tomillero, Iván,Paradís-Bas, Marta,De Pinho Ribeiro Moreira, Ibério,Bofill, Josep María,Nicolás, Ernesto,Albericio, Fernando
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supporting information
p. 5409 - 5422
(2015/05/13)
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- Design, synthesis and docking study of 5-(substituted benzylidene) thiazolidine-2,4-dione derivatives as inhibitors of protein tyrosine phosphatase 1B
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A series of novel 5-(substituted benzylidene)thiazolidine-2,4-dione derivatives was designed, and synthesized based on our previous studies. Also their activities were evaluated as competitive inhibitors of protein tyrosine phosphatase 1B (PTP1B). Compounds 6d-6g, 7b, 7c, 7e, 7j, 7k, 7m, 14b and 14e-14f showed potent inhibitory effects against PTP1B, and compound 7e, the most potent among the series, had an IC50 of 4.6 μM. Also a Surflex-Dock docking model of 7e was studied. Compound 7e showed a negative binding energy of -7.35 kcal/mol and a high affinity to PTP1B residues (Gly220, Ala217, Arg221, Asp181, Ser216, Cys215, Phe182, Gln262 and Ile219) in the active sites, indicating that it may stabilize the open form and generate tighter binding to the catalytic sites of PTP1B.
- Wang, Zengtao,Liu, Zhiguo,Lee, Woojung,Kim, Su-Nam,Yoon, Goo,Cheon, Seung Hoon
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supporting information
p. 3337 - 3340
(2014/07/22)
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- Synthesis of banana-like 1,3-dihydroxybenzene and 2,7-dihydroxynaphthalene esters and luminescence of their terbium(III) complexes
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New esters of 1,3-dihydroxybenzene and 2,7-dihydroxynaphthalene with 4-(4-alkoxybenzoyloxy)-2-(or 3-)methoxybenzoic acids were synthesized. The correlation between their structure and liquid crystal properties was examined, and the luminescence characteristics of terbium(III) complexes with these esters were studied.
- Novikova,Kilimenchuk,Kondrat'Eva,Meshkova,Topilova
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p. 978 - 983
(2011/10/01)
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- Concise synthesis of licochalcone a through water-accelerated [3,3]-sigmatropic rearrangement of an aryl prenyl ether
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Claisen-Schmidt condensation of 4-(tetrahydropyran-2-yloxy)acetophenone with 2-methoxy-4-[(3-methylbut-2-en-1-yl)oxy]benzaldehyde gave a THP-protected chalcone ether. Removal of the THP group under mild acidic conditions gave the corresponding chalcone ether, which underwent a water-accelerated Claisen rearrangement under microwave irradiation or heating in a sealed tube in aqueous ethanol to give a good yield of licochalcone A, which has diverse biological activities; no product of deprenylation or abnormal Claisen rearrangement was formed. The abnormal Claisen rearrangement of -substituted allyl aryl ethers is known to be a problem in [3,3]-sigmatropic rearrangement reaction; this, however, was not detected in our water-accelerated system.
- Jeon, Jae-Ho,Kim, Mi Ran,Jun, Jong-Gab
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experimental part
p. 370 - 376
(2011/04/22)
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- Selective deprotection of phenolic polysulfonates
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Nosylates of phenols can be selectively deprotected by thiocresol anions in DMSO. Successful deprotection can be accomplished in molecules containing aryl-appended halides, ethers, aldehydes, alkanesulfonates or arylsulfonates. Nosylate deprotection is accomplished by the CS bond rupture which is believed to proceed by nucleophilic aromatic substitution.
- Chapman, Erin E.,Langler, Richard F.
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experimental part
p. 19 - 26
(2010/10/04)
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- Chromogenic substrates of sialidase and methods of making and using the same
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The subject invention discloses materials and methods for the design, synthesis, and biochemical evaluation of chromogenic substrate compounds for sialidases of bacterial, viral, protozoa, and vertebrate (including humans) origin. In particular, this invention provides a novel class of effective compounds as chromogenic substrates of these sialidases which yield chromogenic products after reactions catalyzed by sialidase take place. Also provided are methods of making these substrate compounds, methods of diagnosis and prognosis of sialidase related diseases using these substrate compounds.
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- Influence of hydrogen bonding in the activation of nucleophiles: PhSH- (catalytic) KF in N-methyl-2-pyrrolidone as an efficient protocol for selective cleavage of alkyl/aryl esters and aryl alkyl ethers under nonhydrolytic and neutral conditions
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The nucleophilicity of arenethiols can be augmented via hydrogen bonding with 'naked' halide anion. The activity of the halide anions follow the order F- ?Cl- ~ Br- ~ I- and is dependent on the countercation (Bu4N ~ Cs ~ K > Na ?Li). The solvent plays an important role in nucleophilic activation as well as regeneration of the effective nucleophile (e.g. ArS-) and those with high dielectric constant, high molecular polarizability, high donor number (DN), and low acceptor number (AN) are the most effective. Selective deprotection of alkyl/aryl esters and aryl alkyl ethers can be achieved under nonhydrolytic and neutral conditions by the treatment with thiophenol in 1-methyl-2-pyrrolidone (NMP) in the presence of a catalytic amount of KF. Aryl esters are selectively deprotected in the presence of alkyl esters and alkyl methyl ethers during intramolecular competitions.
- Chakraborti, Asit K.,Sharma, Lalima,Nayak, Mrinal K.
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p. 2541 - 2547
(2007/10/03)
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- A mild and chemoselective method for deprotection of aryl acetates and benzoates under non-hydrolytic condition
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Chemoselective deprotection of aryl acetates and benzoates can be achieved under non-hydrolytic condition by treatment with K2CO3 in N-methyl-2-pyrrolidone (NMP) at 100°C. Selective cleavage of aryl acetates and benzoates take place in the presence of alkyl carboxylates during intramolecular competitions.
- Chakraborti, Asit K,Sharma, Lalima,Sharma, Upasana
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p. 9343 - 9346
(2007/10/03)
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The aromatic hydroxyaldehydes 3a-3g, 5a-Sf, 8, 10 can be prepared by the action of BCl3, BBr3 or trifluoromethanesulfonic acid, on the aryl formates 1a-1f, 4a-e, 7, 9 via Fries rearrangement. BBr3 is more effective than BCl3. The activating ability of BBr3 can be improved by addition of FeCl3. Rearrangements which are induced by trifluoromethanesulfonic acid can give rise to the formations of regioisomers, which might be different from the products formed when the reaction is performed with Lewis acids. The yields of the aldehydes are lowered by subsequent condensation reactions. This view was confirmed by the isolation of a condensation product, which was characterized as a dibenzo[a,j]xanthene derivative 6 by crystal structure analysis. For the Fries rearrangement of formyl groups a new mechanism is proposed. 2-Hydroxy-1-naphthaldehyde 5c can be obtained in good yield from formic acid, BBr3, and 2-naphthol.
- Ziegler, Georg,Haug, Erwin,Frey, Wolfgang,Kantlehner, Willi
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p. 1178 - 1187
(2007/10/03)
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- Selective deprotection of propargyl ethers using tetrathiomolybdate
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Benzyltriethylammonium tetrathiomolybdate, [PhCH2NEt3]2MoS4, 1 deprotects propargyl ethers of alcohols and phenols in a selective manner in high yields. Easily reducible groups like nitro, aldehyde, keto and allyl are not affected.
- Swamy,Ilankumaran, Palanichamy,Chandrasekaran, Srinivasan
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p. 513 - 514
(2007/10/03)
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- PEPTIDE SYNTHESIS BY A COMBINATION OF SOLID-PHASE AND SOLUTION METHODS I: A NEW VERY ACID-LABILE ANCHOR GROUP FOR THE SOLID PHASE SYNTHESIS OF FULLY PROTECTED FRAGMENTS
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The synthesis of a new polymeric support for the preparation of fully protected peptide fragments by the Fmoc/t-butyl method is described.Data for coupling yields and racemization data are given.Cleavage from the resin is performed by very mild acidolysis.
- Mergler, M.,Tanner, R.,Gosteli, J.,Grogg, P.
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p. 4005 - 4008
(2007/10/02)
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- 3-Methoxy-4-(2-nitrovinyl)phenyl glycosides as potential chromogenic substrates for the assay of glycosidases.
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Selective glycosidation of 2,4-dihydroxybenzaldehyde with either 2,3,4, 6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide, 2-acetamido-3,4,6-tri-O-acetyl-alpha-D-glucopyranosyl chloride, or 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide afforded the corresponding 4-O-glycosyl derivatives. Subsequent O-methylation, O-deacetylation, and condensation with nitromethane afforded the appropriate beta-glycoside of 3-methoxy-4-(2-nitrovinyl)phenol. The phenol is highly coloured at alkaline pH so that these glycosides may be suitable as chromogenic substrates for the assay of glycosidases.
- Patel,Richardson
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p. 241 - 249
(2007/10/02)
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