- REARRANGEMENT OF DIMETHYLPHENYLACYLATES USING ZEOLITES
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The present invention relates to a Fries rearrangement of specific dimethylphenylacylates to form the desired respective hydroxyaryl ketones having two methyl groups bound to the aromatic ring. It has been found that the process is surprisingly very specific in view of the number and position of the methyl group(s) bound to the aromatic ring.
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Page/Page column 9-11
(2021/08/14)
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- Synthesis and characterization of (E)-2-(1-hydrazonoethyl)-4,5-dimethylphenol from 2-hydroxy-4,5-dimethylacetophenone
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This study reports the development of a novel substituted hydrazone prepared from 2-hydroxy-4,5-dimethylacetophenone and hydrazine in alkaline medium at controlled conditions which yields as corresponding hydrazone [(E)-2-(1-hydrazonoethyl)-4,5-dimethylphenol]. The structure of synthesized (E)-2-(1-hydrazonoethyl)-4,5-dimethylphenol was elucidated by elemental analysis and spectroscopic techniques like infrared spectroscopy, ultraviolet–visible spectroscopy, high-performance liquid chromatography, proton nuclear magnetic resonance and mass spectrum.
- Deshmukh, Ajay,Dwivedi, Poonam,Gagare, Dinkar,Lokhande, Rama,Patil, Raju
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- Synthesis and anti-inflammatory activity of 2-oxo-2H-chromenyl and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates
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Cycloaddition reaction of 4-chloro-2-oxo-2H-chromene-3-carbaldehydes (3a-g) and 4-chloro-2H-chromene-3-carbaldehydes (7a-h) with activated alkynes (4a-b) provided the 2-oxo-2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (5a-n) and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (8a-p). All the prepared compounds were screened for anti-inflammatory activity. In vitro anti-inflammatory activity data demonstrated that the compounds 5g, 5i, 5k-l and 8f are effective among the tested compounds against TNF-α (1.108 ± 0.002, 0.423 ± 0.022, 0.047 ± 0.001, 0.070 ± 0.002 and 0.142 ± 0.001 μM) in comparison with standard compound Prednisolone (0.033 ± 0.002 μM). Based on in vitro results, three compounds (5i, 5k and 8f) have been selected for in vivo experiments and these compounds are identified as better compounds with respect to anti-inflammatory activity in LPS induced mice model. Compound 5i was identified as potent and showed significant reduction in TNF-α and IL-6.
- Bhimapaka, China Raju,Karri, Shailaja,Kuncha, Madhusudana,Kurma, Siva Hariprasad,Sistla, Ramakrishna
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- Substrate substitution effects in the Fries rearrangement of aryl esters over zeolite catalysts
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The catalytic transformation of aryl esters to hydroxyacetophenones via Fries rearrangement over solid acids is of interest to avoid the use of corrosive and toxic Lewis and Br?nsted acids traditionally applied. Microporous zeolites are known to catalyze the reaction of simple substrates such as phenyl acetate, but their application to substituted derivatives has received limited attention. To refine structure-activity relationships, here we examine the impact of various parameters including the solvent polarity, water content, acidic properties, and framework type on the reaction scheme in the Fries rearrangement of p-tolyl acetate over common solid acids. The results confirm the importance of providing a high concentration of accessible Br?nsted acid sites, with beta zeolites exhibiting the best performance. Extension of the substrate scope by substituting methyl groups in multiple positions identifies a framework-dependent effect on the rearrangement chemistry and highlights the potential for the transformation of dimethylphenyl acetates. Kinetic studies show that the major competitive path of cleavage of the ester C-O bond usually occurs in parallel to the Fries rearrangement. The possibility of sequentially acylating the resulting phenol depends on the substrate and reaction conditions.
- Bonrath, Werner,Létinois, Ulla,Lin, Ronghe,Medlock, Jonathan,Mitchell, Sharon,Netscher, Thomas,Pérez-Ramírez, Javier,Stemmler, René T.
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p. 4282 - 4292
(2020/07/30)
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- Synthesis of natural product inulavosin via Ga(OTf)3-Catalyzed Hetero Diels–Alder Dimerization of salicyl alcohol derivative
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Inulavosin, a natural melanogenesis inhibitor, has been synthesized smoothly from readily available and inexpensive starting materials by using a Ga(OTf)3-catalyzed room temperature hetero Diels–Alder dimerization of salicyl alcohol derivative and a regioselective phenol monobromination as the key steps.
- Gong, Pi-Xian,Li, Hui-Jing,Wang, Meirong,Cheng, Yun-Fei,Wu, Yan-Chao
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supporting information
p. 2911 - 2916
(2018/10/15)
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- Use of 4-cyanocoumarins as dienophiles in a facile synthesis of highly substituted dibenzopyranones
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(Chemical Equation Presented) A new synthesis of dibenzopyranones 14 is reported via the Diels-Alder cycloaddition of 4-cyanocoumarins 12 with 1-silyloxydienes 10 to give the adducts 13 which are then converted into 14 in one step via treatment with base and loss of the cyano and silyloxy groups.
- Jung, Michael E.,Allen, Damian A.
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supporting information; scheme or table
p. 757 - 760
(2009/08/07)
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- A facile synthetic method of herbicidal 2,-dihydro-3-methylene-2-substituted - phenyl-1hisoindol-1-one derivatives
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Herbicidal 2,3-dihydro-3-methylene-2-substitutedphenyl-1 H-isoindol-1-one derivatives 7 have been synthesized. They were prepared from the easily available phenol derivatives 1 in 5 steps in moderate yields.
- Kim, Jae Nyoung,Ryu, Eung K.
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- CHELATES FROM THE REACTIONS OF CARBOXYLIC ACIDS WITH 3,4-XYLENOL IN THE PRESENCE OF BORON TRIFLUORIDE ETHER COMPLEX
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Reactions of 3,4-xylenol with acetic, propionic, butyric, valeric, phenylacetic, and benzoic acids catalyzed by boron trifluoride ether complex give hitherto unknown BF2-containing chelates, which are converted into the corresponding ketones when heated with aqueous ethanol.The chelates and ketones were characterized by spectral data.
- Starkov, S. P.,Panasenko, A. I.,Volkotrub, M. N.,Zhidkova, L. A.
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p. 288 - 289
(2007/10/02)
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