- Conformational analysis and interpretation of ν(OH) bands in the IR spectra of 1′-hydroxyethyl derivatives of 1,4-benzo- and 5,8-dihydroxy-1,4-naphthoquinones: A DFT study
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Detailed conformational analysis of the molecule of 1′-hydroxyethyl- 1,4-benzoquinone (3) by the B3LYP/cc-pVTZ method revealed predominance of rotamers with the free 1′-OH group in the gas phase. B3LYP/cc-pVTZ calculations with inclusion of solvent (cyclohexane) effect in the framework of the polarizable continuum model predict an increase in the percentage of such rotamers compared to the corresponding gas-phase values. The results obtained are in qualitative agreement with the experimentally observed pattern of ν(OH) bands in the IR spectrum of compound 3 in cyclohexane (hexane) solution. Conformational analysis, in cluding tautomerism and rotamerism, of 2-ethyl-1′,5,8-trihydroxy-1,4-naphthoquinone (2) was performed by the B3LYP method with the 6-31G(d), 6-311G(d), 6-311G(d,p), and cc-pVDZ basis sets. The most abundant tautomeric form of compound 2 is form A in which the substituent bearing 1 '-OH group is in the quinonoid nucleus. In the gas phase, the percentage of all rotamers in form A is about 86% (among them, the proportion of rotamers with the free 1'-OH group is more than 60%). The main reason for splitting of the v(OH) bands in the IR spectra of compounds 2 and 3 in solutions in nonpolar solvents is the equilibrium between rotamers with a relatively weak intramolecular hydrogen bond between the 1′-OH group and the carbonyl group and those having no this bond.
- Glazunov,Berdyshev,Pokhilo,Anufriev
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- Inhibition of Alzheimer's BACE-1 by 2,6-dialkyl-4-chromon-3-yl-1,4-dihydropyridine-3,5-dicarboxylates
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Alzheimer's disease is the most common cause of dementia in the elderly, and no disease-modifying therapy is yet available for this devastating pathology. Deposition of different physicochemical forms of amyloid-β peptides is a critical phase in the patho
- Razzaghi-Asl, Nima,Aggarwal, Neha,Srivastava, Smriti,Parmar, Virinder S.,Prasad, Ashok K.,Miri, Ramin,Saso, Luciano,Firuzi, Omidreza
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- Application of E1cB Elimination in Asymmetric Organocatalytic Cascade Reactions to Construct Polyheterocyclic Compounds
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By introducing a carbon functionality at 2-position of chromane, the formal asymmetric functionalization of the 3-position of 2-substituted chromane has been realized via a highly chemo-, regio-, and stereoselective organocatalytic cascade reaction in a sequential one-pot manner involving an E1cB mechanism governed ring-opening process. Critical to our success was the design of a chiral dipeptide-based bifunctional acid-base organocatalyst, which exhibited high catalytic activity at low catalyst loading (1-0.1 mol %), leading to biologically interesting polyheterocyclic compounds.
- You, Zhi-Hao,Chen, Ying-Han,Tang, Yu,Liu, Yan-Kai
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supporting information
p. 8358 - 8363
(2019/10/16)
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- Synthesis, antiproliferative, and c-Src kinase inhibitory activities of 4-oxo-4H-1-benzopyran derivatives
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A new class of 4-oxo-4H-1-benzopyran derivatives were synthesized and their antiproliferative activity examined against a panel of three human cancer cell lines, that is, breast carcinoma (MDA-MB-468), ovarian adenocarcinoma (SK-OV-3), and colorectal adenocarcinoma (HT-29). Two compounds, that is, 3-hexyl-7,8-dihydroxy-4-oxo-4H-1-benzopyran and (E)-ethyl 3-(7-methoxy-4-oxo-4H-1-benzopyran-3-yl)acrylate were found to be potent against all three cancer cell lines studied at 50 μM concentration. Also, the inhibitory potency of the compounds was evaluated against active Src kinase. A few of these compounds exhibited modest Src kinase inhibitory activity (IC50 = 52-57 μM). Structure-activity relationship studies with respect to the nature and position of substituents on the lead compounds could be further exploited for the design and development of more potent antiproliferative agents and/or Src kinase inhibitors.
- Chand, Karam,Tiwari, Rakesh K.,Kumar, Sumit,Shirazi, Amir Nasrolahi,Sharma, Sweta,Van Der Eycken, Erik V.,Parmar, Virinder S.,Parang, Keykavous,Sharma, Sunil K.
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p. 562 - 572
(2015/03/30)
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- Synthesis and evaluation of c-Src kinase inhibitory activity of pyridin-2(1H)-one derivatives
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Src kinase, a prototype member of the Src family of kinases (SFKs), is over-expressed in various human tumors, and has become a target for anticancer drug design. In this perspective, a series of eighteen 2-pyridone derivatives were synthesized and evaluated for their c-Src kinase inhibitory activity. Among them, eight compounds exhibited c-Src kinase inhibitory activity with IC 50 value of less than 25 μM. Compound 1-[2-(dimethylamino)ethyl]- 5-(2-hydroxy-4-methoxybenzoyl)pyridin-2(1H)-one (36) exhibited the highest c-Src kinase inhibition with an IC50 value of 12.5 μM. Furthermore, the kinase inhibitory activity of compound 36 was studied against EGFR, MAPK and PDK, however no significant activity was observed at the highest tested concentration (300 μM). These results provide insights for further optimization of this scaffold for designing the next generation of 2-pyridone derivatives as candidate Src kinase inhibitors.
- Chand, Karam,Prasad, Suchita,Tiwari, Rakesh K.,Shirazi, Amir N.,Kumar, Sumit,Parang, Keykavous,Sharma, Sunil K.
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- Spinazarin and ethylspinazarin, pigments of the sea urchin Scaphechinus mirabilis
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2,3,5,8-Tetrahydroxy-1,4-naphthoquinone (spinazarin) and 6-ethyl-2,3,5,8-tetrahydroxy-1,4-naphthoquinone (ethylspinazarin) were first isolated from the sea urchin Scaphechinus mirabilis. The structures of spinazarins were established based on analysis of spectroscopic data. A preparative synthetic route to ethylspinazarin was proposed.
- Yakubovskaya,Pokhilo,Mishchenko,Anufriev
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p. 819 - 822
(2008/04/05)
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- Bismuth triflate-catalyzed fries rearrangement of aryl acetates
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Bismuth triflate was found to be an efficient catalyst in the Fries rearrangement of phenyl or 1-naphthyl acetates. Both reactions proceeded smoothly with a catalytic amount of bismuth triflate (10 mol%) to afford the corresponding hydroxyaryl ketone in moderate to good yields in most cases.
- Ollevier, Thierry,Desyroy, Valerie,Asim, Muhammad,Brochu, Marie-Christine
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p. 2794 - 2796
(2007/10/03)
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- Synthetic Utility and Mechanistic Implications of the Fries Rearrangement of Hydroquinone Diesters in Boron Trifluoride Complexes
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Reactions of boron trifluoride methyl and ethyl etherate complexes with hydroquinone diesters yield monomethyl and monoethyl derivatives of acetylhydroquinones. The use of sterically hindered boron trifluoride etherate complexes results in acetylhydroquinone derivatives. This procedure represents a one-step synthesis of acetylhydroquinone derivatives, important building blocks for a variety of synthetic applications.
- Boyer, Jessica L.,Krum, Jodie E.,Myers, Michael C.,Fazal, Aleem N.,Wigal, Carl T.
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p. 4712 - 4714
(2007/10/03)
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- Lipase-catalyzed regioselective protection of hydroxyl groups in aromatic dihydroxyaldehydes and ketones
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Pseudomonas cepacia lipase catalyzes the acetylation in organic solvent of dihydroxyaldehydes and ketones using vinyl acetate as acyl donor. The method is completely regioselective and allows to obtain partially acetylated compounds different from those obtained by enzymic hydrolysis of polyacetoxy arylaldehydes and ketones.
- Nicolosi,Piattelli,Sanfilippo
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p. 3143 - 3148
(2007/10/02)
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- PHOTO-FRIES REARRANGEMENT: REARRANGEMENT OF ACETOXYBENZENE DERIVATIVES
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Photo-Fries rearrangement of 1,4-diacetoxybenzene, 1,3,5-triacetoxybenzene, 1,2,3-triacetoxybenzene and 1,2,4-triacetoxybenzene gave the corresponding mono- and di-C-acetyl migrated products.
- Sharma, Pavan Kumar,Khanna, Rajinder Nath
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p. 159 - 162
(2007/10/02)
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