- Proton Transfer in the Inter- vs Intramolecular Quenching of Naphthol Fluorescence by Amines
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"Charge-transfer" quenching of naphthols by amines can occur via either proton transfer or electron transfer.To gain insight into the quenching mechanism, the room temperature photophysics of 2-naphthol (N2) in the presence of a trialkylamine was compared with that of 2-methoxynaphthalene (N2M) and of an intramolecular equivalent, 1--2-naphthol (1DMN2).To maintain structural analogy, dimethylbenzylamine (DMBA) was used as the quencher.Comparison of steady-state and time-resolved fluorescence for both intermolecular and intramolecular cases leads to the conclusion that the major quenching pathway involves proton transfer.
- Tolbert, Laren M.,Nesselroth, Susan M.
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- Synthesis of novel N- and S-derivatives of 2-naphthol – Promising ligands for the binuclear copper complexes
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N- And S-ligands for binuclear copper complexes were synthesized by the C-sp2-aminomethylation of 2-naphthol with N,N,N′,N′-tetramethyldiaminomethane giving 1-dimethylaminomethyl-2-naphthol, which then reacted with 1,2-ethanedithiol to be converted to thiomethylated derivative. Direct thiomethylation of 2-naphthol and its acetate with formaldehyde and 1,2-ethanedithiol is nonselective, because the reaction involves both O- and C-sp2 reaction centers of the substrate. Binuclear copper complexes with Cu-O-Cu-N or Cu-Cl-Cu-S bonds were prepared.
- Abdullin, Marat F.,Akhmadiev, Nail S.,Akhmetova, Vnira R.,Bikbulatova, El'mira M.,Ibragimov, Askhat G.,Mescheryakova, Ekaterina S.
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- Three-Component Aminoalkylations Yielding Dihydronaphthoxazine-Based Sirtuin Inhibitors: Scaffold Modification and Exploration of Space for Polar Side-Chains
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Nonpolar derivatives of heterocyclic aromatic screening hits like the non-selective sirtuin inhibitor splitomicin tend to be poorly soluble in biological fluids. Unlike sp3-rich natural products, flat aromatic compounds are prone to stacking and often difficult to optimize into leads with activity in cellular systems. The aim of this work was to identify anchor points for the introduction of sp3-rich fragments with polar functional groups into the newly discovered active (IC50 = 5 μM) but nonpolar scaffold 1,2-dihydro-3H-naphth[1,2-e][1,3]oxazine-3-thione by a molecular modeling approach. Docking studies were conducted with structural data from crystallized human SIRT2 enzyme. Subsequent evaluation of the in silico hypotheses through synthesis and biological evaluation of the designed structures was accomplished with the aim to discover new SIRT2 inhibitors with improved aqueous solubility. Derivatives of 8-bromo-1,2-dihydro-3H-naphth[1,2-e][1,3]oxazine-3-thione N-alkylated with a hydrophilic morpholino-alkyl chain at the thiocarbamate group intended for binding in the acetyl-lysine pocket of the enzyme appeared to be promising. Both the sulfur of the thiocarbamate and the bromo substituent were assumed to result in favorable hydrophobic interactions and the basic morpholino-nitrogen was predicted to build a hydrogen bond with the backbone Ile196. While the brominated scaffold showed moderately improved activity (IC50 = 1.8 μM), none of the new compounds displayed submicromolar activity. Synthesis and characterization of the new compounds are reported and the possible reasons for the outcome are discussed.
- Vojacek, Steffen,Beese, Katja,Alhalabi, Zayan,Swyter, S?ren,Bodtke, Anja,Schulzke, Carola,Jung, Manfred,Sippl, Wolfgang,Link, Andreas
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- Triethylsiloxymethyl-N,N-dimethylamine, Et3SiOCH2NMe2: A Dimethylaminomethylation (Mannich) Reagent for O–H, S–H, P–H and Aromatic C–H Systems
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Triethylsiloxymethylamine, Et3SiOCH2NMe2, readily synthesized in high yield by the hydrosilylation reaction between Et3SiH and DMF, is an excellent (N,N-dimethylamino)methyl transfer agent to a representative range of aliphatic alcohols, thiols, and Ph2PH (E–H) materials. The reactions are almost instantaneous at room temperature in inert solvents and require no activating agents to produce E–CH2NMe2 products in high yields and illustrate the title compound as an excellent addition to the family of organic reagents. For aromatic alcohols, electrophilic substitution of the aromatic ring occurs in high yield. Crystal structures of new materials such as the cholestero–CH2NMe2 derivative, 2–4-[bis(N,N-dimethylamino)methyl]-1-naphthol, and the phosphine oxide derived from Ph2PCH2NMe2 are reported.
- Gonzalez, Paulina E.,Sharma, Hemant K.,Chakrabarty, Sanchita,Metta-Maga?a, Alejandro,Pannell, Keith H.
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p. 5610 - 5616
(2017/10/13)
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- Convenient synthesis of 2-Amino-4H-chromenes from photochemically generated o-quinone methides and malononitrile
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2-Amino-4H-chromenes were synthesized in moderate to good yields by the reaction of o-quinone methides photochemically generated from o-(dimethylaminomethyl)phenols with malononitrile. This method was applicable to the synthesis of fluorinated chromenes that were difficult to obtain by other methods. In addition, o-(hydroxymethyl)phenols could be used for the reaction in the presence of tertiary amine bases.
- Fujiwara, Makoto,Sakamoto, Masanori,Komeyama, Kimihiro,Yoshida, Hiroto,Takaki, Ken
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- Oxidative ortho-amino-methylation of phenols via C-H and C-C bond cleavage
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Initiated by CCl3Br, phenols undergo efficient ortho-selective oxidative cross dehydrogenative coupling (CDC) with trimethylamine. When tetramethylethylenediamine (TMEDA) is used instead of trimethylamine, oxidative carbon-carbon activation coupling (CAC) could occur to give the same salicylamines together with CDC by-products. These reactions are accelerated by a gold salt.
- Sun, Wenbo,Lin, Huacan,Zhou, Wenyu,Li, Zigang
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p. 7491 - 7494
(2014/02/14)
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- Magnesium sulfate promoted efficient and green synthesis of aminoalkyl, amidoalkyl and diarylmethane derivatives
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Under solvent-free condition, magnesium sulfate promoted the synthesis of substituted aminoalkyl naphthols, amidoalkyl naphthols and diarylmethane derivatives in excellent yield. Robust dehydrating nature and mild Lewis acidity of magnesium sulfate was exploited to carry out all the transformations.
- Ganesan, S. Selva,Asaithampi
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p. 8380 - 8382
(2015/05/20)
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- β-naphthol in glycerol: A versatile pair for efficient and convenient synthesis of aminonaphthols, naphtho-1,3-oxazines, and benzoxanthenes
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Three-component Betti reaction was carried out in the environmentally benign, inexpensive, non-toxic solvent glycerol. Even in the absence of a catalyst, the reaction went completion with an unprecedented high rate and the expected Betti bases were obtained in up to 91% yield. The reaction works well for representative cyclic, acyclic, aliphatic, and aromatic amines and aldehydes. A benzoxanthene was also prepared in 93% yield following the same methodology with 20 mol% methanesulfonic acid catalyst. Georg Thieme Verlag Stuttgart New York.
- Ganesan, Subramaniapillai Selva,Rajendran, Narendran,Sundarakumar, Sankahr Ilathur,Ganesan, Asaithampi,Pemiah, Brindha
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p. 1564 - 1568
(2013/06/27)
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- New synthesis of 3-amino-1H-benzo[f]chromene-2-carbonitriles
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3-Amino-1H-benzo[f]chromene-2-carbonitriles were synthesized by non-catalytic reaction from Mannich bases of the naphthalene series and malononitrile. Reactive 1-benzylidene(or methylidene)naphthalen-2(1H)-ones were presumed as intermediate products.
- Osipov,Osyanin,Klimochkin, Yu. N.
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p. 398 - 402
(2013/07/26)
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- Synthesis of substituted salicylamines and dihydro-2H-1,3-benzoxazines
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Phenols were converted to their magnesium salts with the MgCl2-Et3N base system and subsequently reacted with Eschenmoser's salt, affording N,N-dimethyl substituted benzylamines in high to excellent yields. A series of mono N-substituted benzylamines were prepared in one-pot syntheses by ortho-formylation of phenols to corresponding salicylaldehydes, which in turn reacted with amines to imines. The imines were subsequently reduced to mono N-substituted benzylamines. Some of these benzylamines were further converted, without work-up, to mono N-substituted dihydro-2H-1,3-benzoxazines.
- Anwar, Hany F.,Skatteb?l, Lars,Hansen, Trond Vidar
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p. 9997 - 10002
(2008/02/13)
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- Generation of quinone methide from aminomethyl(hydroxy)arenes precursors in aqueous solution
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o-Quinone methides (QMs) are an important reactive intermediate for organic synthetic and biological standpoints of view. Photochemical and thermal transformation of N,N-dialkyl-9-aminomethyl-10-phenanthrols and their naphthalene analogs, which act as QM precursors, has been studied. These precursors readily reacted with alkyl vinyl ethers to give 2-alkoxydibenzo[f,h] chroman and 2-alkoxybenzo[f]chroman, respectively. Thermal and photochemical generation of QM was accelerated by the presence of water molecule in reaction solvents and by the formation of anionic micelle and vesicle.
- Matsumoto, Jin,Ishizu, Masayuki,Kawano, Ryu-Ichiro,Hesaka, Daisuke,Shiragami, Tsutomu,Hayashi, Yoshimi,Yamashita, Toshiaki,Yasuda, Masahide
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p. 5735 - 5740
(2007/10/03)
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- A modified Mannich-Type reaction catalyzed by VO(acac)2
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(Equation Presented) A fackile VO(acac)2-catalyzed in situ generation of iminium ions from amine N-oxides and their participation in a modified Mannich-type reaction is described.
- Hwang, Der-Ren,Uang, Biing-Jiun
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p. 463 - 466
(2007/10/03)
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- 2-(aminoalkoxy) phenylalkylamines with antiinflammatory activity
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Compounds of the formula I STR1 including pharmaceutically acceptable salts thereof are disclosed in which R1, R2, R3, and R4 independently represent hydrogen, hydroxy, halo, halogenated alkyl, halogenated alkox
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