- MOF-808 as a recyclable catalyst for the photothermal acetalization of aromatic aldehydes
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Metal-organic frameworks (MOFs) show promise for catalysis applications due to their porosity, high internal surface area, and structural adaptability. Typical acetylation reactions of aldehydes require elevated temperatures and excess alcohol to drive the reactions to completion. In this current work, MOF-808 is used as a heterogeneous catalyst for acetylation of aldehydes in methanol using a mild photothermal process. Optimized conditions gave 72% yield of 2-(dimethoxymethyl)naphthalene in the presence of 10 mol% MOF-808 at 45 °C using only a fluorescent lamp. MOF-808 can be recycled up to 5 times with no loss in catalytic activity. A proof-of-principle substrate scope demonstrates the potential utility for aromatic and aliphatic substrates.
- Rabon, Allison M.,Doremus, Jared G.,Young, Michael C.
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supporting information
(2021/04/02)
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- Chemical Synthesis and Biological Evaluations of Adiponectin Collagenous Domain Glycoforms
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The homogeneously glycosylated 76-amino acid adiponectin collagenous domains (ACDs) with all of the possible 15 glycoforms have been chemically and individually synthesized using stereoselective glycan synthesis and chemical peptide ligation. The following biological and pharmacological studies enabled correlating glycan pattern to function in the inhibition of cancer cell growth as well as the regulation of systemic energy metabolism. In particular, hAdn-WM6877 was tested in detail with different mouse models and it exhibited promising in vivo antitumor, insulin sensitizing, and hepatoprotective activities. Our studies demonstrated the possibility of using synthetic glycopeptides as the adiponectin downsized mimetic for the development of novel therapeutics to treat diseases associated with deficient adiponectin.
- Wu, Hongxiang,Zhang, Yiwei,Li, Yuanxin,Xu, Jianchao,Wang, Yu,Li, Xuechen
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supporting information
p. 7808 - 7818
(2021/05/26)
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- Stereodivergent access to all four stereoisomers of chiral tetrahydrobenzo[f] [1,4]oxazepines, through highly diastereoselective multicomponent Ugi-Joullié reaction
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Starting from easily accessible chiral enantiopure 1,2-amino alcohols and salicylaldehydes, a concise route to cyclic imines has been developed. These chiral cyclic imines undergo a highly diastereoselective Ugi-Joullié reaction to give trans tetrahydrobe
- Pinna, Alessandro,Basso, Andrea,Lambruschini, Chiara,Moni, Lisa,Riva, Renata,Rocca, Valeria,Banfi, Luca
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p. 965 - 972
(2020/01/23)
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- Nickel-Catalyzed Chemoselective Acetalization of Aldehydes With Alcohols under Neutral Conditions
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A molecularly defined NiII-complex catalyzing the chemoselective acetalization of aldehydes with alcohols under neutral conditions is reported. The reaction is general, efficient and showed a wide substrate scope (including aliphatic aldehydes) as well as excellent functional group tolerance. Reusability of the present nickel catalyst is also demonstrated.
- Subaramanian, Murugan,Landge, Vinod G.,Mondal, Akash,Gupta, Virendrakumar,Balaraman, Ekambaram
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supporting information
p. 4557 - 4562
(2019/08/30)
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- Utilization of hexabromoacetone for protection of alcohols and aldehydes and deprotection of acetals, ketals, and oximes under UV irradiation
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Hexabromoacetone (HBA) was efficiently used for the protection of alcohols and aldehydes and deprotection of benzaldehyde dimethyl acetal, solketal, and other acetals and ketals. In only 10?min, the protection of glycerol yielded 90% of solketal and protection of benzaldehyde gave 95% of benzaldehyde dimethyl acetal. The deprotection of benzaldehyde dimethyl acetal under UV irradiation gave over 90% yield of benzaldehyde within 15?s using only 2.5?mol% of HBA. HBA was also successfully used for deoximation. Solvent was found to play an important role in the efficiency of HBA for these reactions.
- Chaiseeda, Kittichai,Chantharadet, Ladawan,Chavasiri, Warinthorn
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p. 1305 - 1323
(2017/10/30)
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- Preparation of acetals from aldehydes and alcohols under basic conditions
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A new, simple protocol for the synthesis of acetals under basic conditions from non-enolizable aldehydes and alcohols has been reported. Such reactivity is facilitated by a sodium alkoxide along with a corresponding trifluoroacetate ester, utilizing formation of sodium trifluoroacetate as a driving force for acetal formation. The usefulness of this protocol is demonstrated by its orthogonality with various acid-sensitive protecting groups and by good compatibility with functional groups, delivering synthetically useful acetals complementarily to the synthesis under acidic conditions from aldehydes and alcohols.
- Grabowski, Jakub,Granda, Jaros?aw M.,Jurczak, Janusz
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p. 3114 - 3120
(2018/05/17)
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- Method for preparing alkoxy acrylate
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The invention discloses a method for preparing an alkoxy acrylate. The method comprises that diazo ester and substituted acetal or ketal as raw materials undergo an alkenylation reaction in the presence of Lewis acid as a catalyst at 50-120 DEG C for 1-24h, then the solvent is drained through pumping and the product is subjected to column chromatography separation so that the alkoxy acrylate compound is obtained. The reaction raw materials and the catalyst are easily available and cheap, the synthesis process is simple, the synthesis cost is greatly reduced, the reaction conditions are mild, the yield is high, the industrialization is easy, the reaction raw materials and the catalyst are clean and non-toxic, and the environmental pollution is small.
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Paragraph 0099
(2018/11/27)
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- Phosphorylated Polyacrylonitrile Fibers as an Efficient and Greener Acetalization Catalyst
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A novel solid acid catalyst (PANEAPF) is developed by immobilization of phosphoric acid on polyacrylonitrile fiber through covalent bonding. Various characterization techniques such as elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), etc. are utilized to confirm the successful grafting and the stability of the fiber catalysts during application. PANEAPF shows high catalytic activity in the acetalization of aldehydes owing to the high utilization efficiency of its functionalized acid sites. In addition, the strong polarity micro-environment in the surface layers of PANEAPF make it highly suitable for catalytic application in both water and alcohol. Furthermore, the fiber catalyst can be applied to the acetalization of aldehydes in a continuous-flow process at room temperature, and shows excellent reactivity and superior recyclability (over 20 times). The many advantages of PANEAPF such as simple preparation, convenient regulation of acid amount, high durability, and eco-friendly process make it very attractive for fixed-bed reactors in the chemical industry.
- Xu, Gang,Cao, Jian,Zhao, Yali,Zheng, Lishuo,Tao, Minli,Zhang, Wenqin
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supporting information
p. 2565 - 2575
(2017/09/25)
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- Efficient acetalization of benzaldehydes using UiO-66 and UiO-67: Substrates accessibility or Lewis acidity of zirconium
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Porous metal-organic frameworks of Zr6O4(OH)4 clusters connected by organic linkers of 1,4-benzenedicarboxylate (UiO-66) and biphenyl-4,4′-dicarboxylate (UiO-67) were prepared using a solvothermal method and used as efficient catalysts for acetalization of benzaldehydes with alcohols. UiO-66 showed better catalytic activity than UiO-67, (i.e. 91% vs 86%) when the catalyst was employed in the benzaldehyde acetalization in methanol for an hour at r.t. (28 °C). UiO-66 was further explored as the catalyst to observe effects of catalyst concentrations, alcohols, bulkier benzaldehydes, and recyclability. The performance of other catalysts, including the MOF precursor, was also examined to compare the activity and to explain the importance of a MOF structure. Relative Lewis acidity of Zr in UiO-66 and UiO-67 was achieved by natural bond orbital (NBO) analysis using DFT/B3LYP method. It was found that accessibility of substrates to internal active sites might play a dominant role than the Lewis acidity of Zr-MOFs.
- Arrozi, Ubed S.F.,Wijaya, Husni W.,Patah, Aep,Permana, Yessi
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- Long-range diastereoselectivity in an Ugi reaction: Stereocontrolled and diversity-oriented synthesis of tetrahydrobenzoxazepines
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Salicylaldehydes and protected 1,2-amino alcohols have been convergently converted into a series of 2,3-dihydrobenzo[f][1,4]oxazepines, which undergo an Ugi-Joullie multicomponent reaction with unusual long-range diastereoselectivity. This protocol allows
- Banfi, Luca,Bagno, Alessandro,Basso, Andrea,De Santis, Carlo,Riva, Renata,Rastrelli, Federico
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p. 5064 - 5075
(2013/11/06)
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- Lewis acid catalyzed intramolecular condensation of ynol ether-acetals. synthesis of alkoxycycloalkene carboxylates
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Treatment of ynol ether-tethered dialkyl acetals with catalytic quantities of scandium triflate in CH3CN gives rise to five-, six-, and seven-membered alkoxycycloalkene carboxylates in good to excellent yields. Tri- and tetrasubstituted carbocyclic and heterocyclic alkenes may be formed by this method, and the products obtained may serve as useful intermediates for natural product synthesis.
- Tran, Vincent,Minehan, Thomas G.
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supporting information
p. 6100 - 6103
(2013/02/26)
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- Synthesis and biological activity of new 1,3-dioxolanes as potential antibacterial and antifungal compounds
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A series of new enantiomerically pure and racemic 1,3-dioxolanes 1-8 was synthesized in good yields and short reaction times by the reaction of salicylaldehyde with commercially available diols using a catalytic amount of Mont K10. Elemental analysis and spectroscopic characterization established the structure of all the newly synthesized compounds. These compounds were tested for their possible antibacterial and antifungal activity. Biological screening showed that all the tested compounds, except 1, show excellent antifungal activity against C. albicans, while most of the compounds have also shown significant antibacterial activity against S. aureus, S. epidermidis, E. faecalis and P. aeruginosa.
- Kuecuek, Hatice Baspinar,Yusufoglu, Ayse,Mataraci, Emel,Doesler, Sibel
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experimental part
p. 6806 - 6815
(2011/11/04)
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- Synthesis of substituted dihydrobenzothiopyrans and dihydrobenzopyrans by cation-mediated cyclisation reactions
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Treatment with acid of thiosalicylaldehyde- and salicylaldehyde-derived phenyl 3-phenyl-2-propenyl thioethers and ethers possessing latent oxonium ion functionality triggers simple or tandem cyclisation to give substituted dihydrobenzothiopyrans and dihyd
- Bonfanti, Jean-Fran?ois,Craig, Donald
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p. 3719 - 3723
(2007/10/03)
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- An efficient and versatile procedure for the synthesis of acetals from aldehydes and ketones catalyzed by lithium tetrafluoroborate
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Acetals are obtained in good to excellent yields by treatment of aldehydes and ketones with trialkyl orthoformate and the corresponding alcohol in the presence of a catalytic amount of lithium tetrafluoroborate. Due to the mild reaction conditions, this method is compatible with acid-sensitive substrates.
- Hamada, Nao,Kazahaya, Kiyoshi,Shimizu, Hisashi,Sato, Tsuneo
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p. 1074 - 1076
(2015/10/07)
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- An efficient protection of carbonyls and deprotection of acetals using decaborane
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Carbonyls were efficiently converted to the corresponding dimethyl acetals at room temperature using trimethyl orthoformate and 1 mol% of decaborane under a nitrogen atmosphere. In turn, acetals were deprotected to the corresponding carbonyls using 1 mol% of decaborane in aqueous THF chemoselectively.
- Lee, Seung Hwan,Lee, Ji Hee,Yoon, Cheol Min
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p. 2699 - 2703
(2015/10/07)
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- Efficient acetalisation of aldehydes catalyzed by titanium tetrachloride in a basic medium
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The acetalisation of aliphatic and aromatic aldehydes is achieved in a basic medium by using catalytic amount of Ti(IV) chloride in MeOH in the presence of NH3 or Et3N. The present protocol shows many advantages over the well known base or acid catalysis: in fact, in contrast to base-promoted acetalisation, aldehydes with electron-rich carbonyl groups react easily, enolizable aldehydes do not undergo aldol condensation and, in contrast to acid-catalysis, migration of the double bond does not occur in the preparation of α,β-unsaturated acetals.
- Clerici, Angelo,Pastori, Nadia,Porta, Ombretta
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p. 15679 - 15690
(2007/10/03)
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- A simple one-pot procedure for the conversion of aldehydes to methyl esters
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Several methyl esters were obtained by an efficient and simple one-pot procedure from the corresponding aldehydes in high yields. This procedure involves dimethyl acetal formation from aldehydes and subsequent oxidation.
- Rhee, Hakjune,Kim, Jin Yeon
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p. 1365 - 1368
(2007/10/03)
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- Monomers and polymers containing acetal and aldehyde groups
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Various novel acetal- and aldehyde-containing monomers are prepared. They can be polymerized and copolymerized by conventional polymerization techniques. The polymers contain repeating units derived from one or more ethylenically or allylically unsaturate
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- SUBSTITUTED 4-PHENOXY OR 4-PHENYLTHIO PROLINES
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This invention is directed to substituted 4-phenoxy and 4-phenylthio prolines of the formula STR1 which possess useful hypotensive activity.
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- Acetal Formation Facilitated in 2-Hydroxyaryl Aldehydes by Intramoleculedar Acyl Group Transfer
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Convenient preparations of synthetically useful acetals, a dithioacetal and an oxathiolan from the 2-acyl derivatives of 2-hydroxyaryl aldehydes under basic conditions are described.The mildness of the reaction conditions is illustrated by the formation of an ethoxycarbonyl-substituted dioxolan.The reaction is dependent upon an intramolecular acetyl group transfer and the mechanism of the reaction is discussed.Some broader implications of this type of acyl transfer are discussed.
- Liepa, Andris J.,Morton, Trevor C.
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p. 1747 - 1757
(2007/10/02)
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- On the Chemistry of Binding Sites, VI On the Suitability of Various Aldehydes and Ketones as Binding Sites for Monoalcohols
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Suitable binding sites in the chemoselective affinity chromatography should posses a favourable state and a very fast adjustment of the equilibrium with substrates.Aldehydes and ketones of various structure (1-16), from which 3-7 and 10 were prepared for the first time, were investigated for their suitibility to bind monoalcohols via a covalent acetal bond.Especially advantageous were cyclic hemiacetals which showed on acidic catalysis with monoalcohols a fast and reversible formation of acetals.Out of these 1,3-dihydro-1-isobenzofuranol (1a), 1,3-dihydro-7-methoxy-1-isobenzofuranol (5a), and 2H-chromen-2-ol (10) with very fast kinetics seemed to be especially suitable.Acetals of different alcohols were prepared as well and their hydrolytic behaviour was studied.For the preparation of corresponding polymers the polymerizable derivative 20 was synthesized.
- Wulff, Guenter,Wolf, Gabriele
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p. 1876 - 1889
(2007/10/02)
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