613-45-6Relevant articles and documents
Synthesis of 4-Methoxysalicylaldehyde via selective monomethylation of 2,4-dihydroxybenzaldehyde
Jin, Hai-Shan,Zhang, Li-Ming,Yan, Zhi-Wei,Ma, Feng-Yan
, p. 144 - 145 (2012)
4-Methoxysalicylaldehyde, a naturally occurring product, has a range of industrial applications in the preparation of organic compounds, drugs and therapeutic agents. 4-Methoxysalicylaldehyde can be synthesised via selective monomethylation of 2,4-dihydroxybenzaldehyde in toluene in the presence of NaHCO3 in higher yield using cheaper reagents with little production of dimethylation product compared to previous methods. The location of the methoxyl group was confirmed by conversion to 3-acetyl-7-methoxycoumarin by condensation with ethyl acetoacetate.
STYRENES FROM DORSTENIA BARNIMIANA
Woldu, Yordanos,Abegaz, Berhanu,Botta, Bruno,Monache, Giuliano Delle,Monache, Franco Delle
, p. 1227 - 1228 (1988)
Three new styrenes have been isolated from Dorstenia barnimiana (Moraceae) and were assigned the structures 6-methoxy-5-vinylbenzofuran, 4,6-dimethoxy-5-vinylbenzofuran and 2,4-dimethoxystyrene.Key Word Index - Dorstenia barnimiana; Moraceae; styrenes; benzofurans; bergaptene.
Synergistic effect of iodine doped TiO2 nanoparticle/g-C3N4 nanosheets with upgraded visible-light-sensitive performance toward highly efficient and selective photocatalytic oxidation of aromatic alcohols under blue LED irradiation
Akhtar, Behrooz,Ghafuri, Hossein,Rashidizadeh, Afsaneh
, (2021)
Selective oxidation of alcohols via photocatalytic processes by O2 molecules as a green oxidant and visible light has a great potential to dissolve the environmental crisis and worldwide energy. Herein, I-TiO2 Nanoparticle/g-C3N4 Nanosheets (I-TiO2/CNNSs) heterostructured composite with different contents of graphitic carbon nitride nanosheets has been successfully prepared via a facile and simple procedure. The structure of the I-TiO2/CNNSs nanocomposite was analyzed by FT-IR, XRD, EDX, BET, TGA, FESEM, DRS, and PL techniques. The resultant nanocomposite (I-TiO2/(20 wt%)CNNSs) exhibits superior photocatalytic efficiency than its pristine g-C3N4 and iodine doped TiO2 for the oxidation of benzyl alcohols under the illumination of visible light (λ ≥ 400 nm). Introduction of the I-TiO2 on the surface of CNNSs can improve the absorption ability in the visible region and separation efficiency of charge carriers during the photocatalytic oxidation. Hence, these obtained results show that the I-TiO2/(20 wt%)CNNSs nanocomposite possess high photocatalytic performance and excellent reusability in oxidation reactions and other sustainable energy-related applications.
Effect of Substituents on Partial Photocatalytic Oxidation of Aromatic Alcohols Assisted by Polymeric C3N4
Krivtsov, Igor,Ilkaeva, Marina,García-López, Elisa I.,Marcì, Giuseppe,Palmisano, Leonardo,Bartashevich, Ekaterina,Grigoreva, Ekaterina,Matveeva, Ksenia,Díaz, Eva,Ordó?ez, Salvador
, p. 2713 - 2724 (2019)
In the present work we scrutinize the effect of substituents in the phenyl ring of the benzyl alcohol on its photo-oxidation to the corresponding benzaldehyde driven by polymeric carbon nitride photocatalyst in aqueous medium. It has been established that electron donating (ED) substituents in para- and ortho-position with respect to the CH2OH-group promote the reactivity of the substrate without compromising the selectivity towards benzaldehyde formation, maintaining it in the range of 84–98 %, if compared to the unsubstituted molecule. The same observation is true for meta-substituted benzyl alcohol with an electron withdrawing (EW) group. On the other hand, the presence of ED-group in meta-position or EW-group in para-position with respect to the CH2OH-group reduces the reactivity as well as the selectivity towards the aldehyde production, resulting in the values of selectivity ranging from 40 to 80 %. Quantum chemical calculations have allowed to establish that the reactivity correlates with the positive charge on the benzylic carbon in benzyl alcohol cation intermediate, while the selectivity, most probably, is conditioned by a negative charge on the carbon atoms in the phenyl ring being a target for an electrophile attack. The modification of the polymeric C3N4 photocatalyst with H2O2 reduces the unselective benzyl alcohol oxidation, thus favouring the higher selectivity towards benzaldehyde production.
Unexpectedly ambivalent O2 role in the autocatalytic photooxidation of 2-methoxybenzyl alcohol in water
Palmisano, Giovanni,Scandura, Gabriele,Augugliaro, Vincenzo,Loddo, Vittorio,Pace, Andrea,Tek, Bilge Sina,Yurdakal, Sedat,Palmisano, Leonardo
, p. 37 - 42 (2015)
Abstract An unusual autocatalytic photooxidation of 2-methoxybenzyl alcohol has been observed under UV irradiation in aqueous medium. The homogeneous oxidation is catalyzed by the corresponding aldehyde that is also the main oxidation product. The trend of alcohol disappearance rate matches the typical shape of an autocatalytic process, where a crucial and ambivalent role is played by the presence of molecular oxygen. Low oxygen concentrations give rise to a zero-order reaction since the beginning of irradiation, while higher amounts of oxygen reduce the alcohol oxidation rate until the aldehyde reaches a concentration high enough to speed up the alcohol's conversion. Experiments performed by varying alcohol, aldehyde and oxygen concentrations in both aqueous and organic media suggest that the alcohol oxidation is initially favored by the presence of oxygen. Once the formed aldehyde competes for photon absorption, the oxidation is driven by aldehydes alpha cleavage leading to reactive oxygenated species in aqueous medium. An excess of oxygen quenches the latter processes thus inhibiting/slowing down the reaction.
C70Fullerene Catalyzed Photoinduced Aerobic Oxidation of Benzylamines to Imines and Aldehydes
Kumar, Inder,Kumar, Rakesh,Gupta, Shiv Shankar,Sharma, Upendra
supporting information, p. 6449 - 6457 (2021/05/29)
C70 fullerene catalyzed photoinduced oxidation of benzylic amines at ambient conditions has been explored here. The developed strategy's main feature includes the additive/oxidant-free conversion of benzylic amine to corresponding imine and aldehydes. The reaction manifests broad substrate scope with excellent function group leniency and is applicable up to the gram scale. Further, symmetrical secondary amines can also be synthesized from benzylic amine in a one-pot two-step process. Various experiments and density functional theory studies revealed that the current reaction involves the generation of reactive oxygen species, single electron transfer reaction, and benzyl radical formation as key steps under photocatalytic conditions.
α-MnO2 modified exfoliated porous g-C3N4 nanosheet (2D) for enhanced photocatalytic oxidation efficiency of aromatic alcohols
Nanda, Binita,Nanda, Braja B.,Pradhan, Manas Ranjan,Rath, Dharitri,Sethi, Ratikanta
, (2021/06/18)
Porous graphitic carbon nitride (g-C3N4) was synthesized by taking melamine and ammonium bicarbonate through single-step calcination method followed by ultrasonication to obtain exfoliated porous g-C3N4 (2D) nanosheets. Further enhancement of photocatalytic performance, g-C3N4 nanosheet (2D) was further modified with different weight percentage of (1, 3, 5, and 7) of MnO2. The introduction of α-MnO2 onto the g-C3N4 nanosheet establishes an interlayer channels to promote the migration of charge carriers through the valence band and conduction band of the prepared composite MnO2@g-C3N4. The transformation of photo induced charge carriers adopt the Z-scheme mechanism rather band-transfer mechanism. The accumulated photo generated electrons in conduction band of g-C3N4 is more electro negative than the potential of (O2/O2–.) and able to reduce oxygen to superoxide (O2–.) radical. At the same time, the holes in valence band of α-MnO2 are more electro positive than the potential of (OH–/OH.) and help in oxidate OH– to hydroxyl (OH.) radical. Among all the composites, 3 wt% MnO2 modified g-C3N4 shows the best photocatalytic oxidation efficiency towards all the aromatic alcohols. In presence of visible light, heterojuction formation, and formation of active charged species (OH. and O2–.) were mostly responsible for photocatalytic oxidation of aromatic alcohols through free radical mechanism.
Fe Doped MIL-101/Graphene Nanohybrid for Photocatalytic Oxidation of Alcohols Under Visible-Light Irradiation
Wang, Mingming,Ma, Yali,Lv, Bolin,Hua, Fenglin,Meng, Shuangyan,Lei, Xuedi,Wang, Qingtao,Su, Bitao,Lei, Ziqiang,Yang, Zhiwang
, p. 2384 - 2395 (2021/01/04)
A novel photoactive porous material of GR/FeMIL-101 based on FeMIL-101 metal organic frameworks (MOFs) was successfully synthesized via a simple hydrothermal method. The structural and photoelectric properties of the GR/FeMIL-101 was analyzed by XRD, SEM, TEM, TGA, XPS, UV–vis DRS, FT-IR, PL and EIS methods. The photocatalytic performance for the selective oxidation of benzyl alcohol with GR/FeMIL-101 as catalysts was evaluated under visible light irradiation. The results showed that the GR/FeMIL-101 nanohybrid had better photocatalytic performance than both of FeMIL-101 and the pristine MIL-101. It was further found that the incorporation of Fe and MIL-101 caused valence fluctuations of Fe3+/Fe2+ which improved the absorption of visible-light and increased the separation efficiency of photogenerated charges. In addition, the combination of FeMIL-101 and GR could further promote the transfer rate of the photoelectrons. The mechanism of the reaction revealed that ·O2? was the dominating active specie in this reaction through active species trapping experiments. Graphic Abstract: [Figure not available: see fulltext.]Fe doped MIL-101/GR nanohybrid was successfully synthesized as an efficient photocatalyst for selective oxidation of alcohols under visible-light and shown a best conversion of 50%. Analyses revealed that Fe was successfully doped into the MIL-101, valence fluctuation of Fe2+/Fe3+ not only improved the visible-light absorption but also increased the separation rate of photoexcited carriers. Graphene further improved the transportation rate of electron (e-). Subsequently, the possible photocatalytic mechanism for the selective oxidation of alcohols was proposed. It was proved that superoxide radicals (·O2-) was the main active species when the reaction was performed under Oxygen atmosphere.
A new catalytic approach for aerobic oxidation of primary alcohols based on a Copper(I)-thiophene carbaldimines
Lagerspets, Emi,Valbonetti, Evelyn,Eronen, Aleksi,Repo, Timo
, (2021/06/03)
We report here novel Cu(I) thiophene carbaldimine catalysts for the selective aerobic oxidation of primary alcohols to their corresponding aldehydes and various diols to lactones or lactols. In the presence of the in situ generated Cu(I) species, a persistent radical (2,2,6,6-tetramethylpiperdine-N-oxyl (TEMPO)) and N-methylimidazole (NMI) as an auxiliary ligand, the reaction proceeds under aerobic conditions and at ambient temperature. Especially the catalytic system of 1-(thiophen-2-yl)-N-(4-(trifluoromethoxy)phenyl)methanimine (ligand L2) with copper(I)-iodide showed high reactivity for all kind of alcohols (benzylic, allylic and aliphatic). In the case of benzyl alcohol even 2.5 mol% of copper loading gave quantitative yield. Beside high activity under aerobic conditions, the catalysts ability to oxidize 1,5-pentadiol to the corresponding lactol (86% in 4 h) and N-phenyldiethanolamine to the corresponding morpholine derivate lactol (86% in 24 h) is particularly noteworthy.
3-(5-METHOXY-1-OXOISOINDOLIN-2-YL)PIPERIDINE-2,6-DIONE DERIVATIVES AND USES THEREOF
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Page/Page column 292, (2021/06/26)
The present disclosure relates to compounds of formula (I') and pharmaceutical compositions and their use in reducing Widely Interspaced Zinc Finger Motifs (WIZ) expression levels, or inducing fetal hemoglobin (HbF) expression, and in the treatment of inherited blood disorders (e.g., hemoglobinopathies, e.g., beta-hemoglobinopathies), such as sickle cell disease and beta-thalassemia.
