614-80-2Relevant articles and documents
Unprecedented Dearomatized Spirocyclopropane in a Sequential Rhodium(III)-Catalyzed C?H Activation and Rearrangement Reaction
Wang, Xiaoming,Li, Yingzi,Knecht, Tobias,Daniliuc, Constantin G.,Houk,Glorius, Frank
, (2018)
An unprecedented dearomatized spirocyclopropane intermediate was discovered in a sequential Cp*RhIII-catalyzed C?H activation and Wagner–Meerwein-type rearrangement reaction. How the oxidative O?N bond is cleaved and the role of HOAc were uncov
1-8H-pyrano[3,2-g]benzoxazol-8-ones from 7-methoxyimino-4-methylchromene-2,8-dione
Nicolaides, Demetrios N.,Bezergiannidou-Balouctsi, Catherine,Litinas, Konstantinos E.,Malamidou-Xenikaki, Elizabeth,Mentzafos, Demetrios,Terzis, Aris
, p. 9127 - 9136 (1993)
7-Methoxyimino-4-methylchromene-2,8-dione 3, easily prepared from the quinone 1 reacts thermally with methylaromatics 5(a-g), benzyl derivatives 13(a-c), halo derivatives 14(a-c) to give mainly oxazolocoumarins. Products 8(a-d) are obtained from 5(a-d), 13(a-c). Compound 9 is obtained from 5(a-c) and 13(a-c), compounds 15(a-c) are obtained from 14(a-c), the aminophenol 10 and coumarin 16 are obtained from 5f and 14c respectively, while coumarin 12 is obtained from 5g. The reaction of 3 with N-methyl-aniline and N,N-dimethylbenzylamine gives compound 10 and 8a respectively.
Synthesis method of 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane
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Paragraph 0030-0032; 0037-0039, (2021/04/29)
The invention discloses a synthesis method of 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, which comprises the following steps: acetylating o-aminophenol serving as a starting material to obtain o-acetamidophenol, condensing the o-acetamidophenol with hexafluoroacetone trihydrate to obtain 2, 2-bis (3-acetamido-4-hydroxyphenyl) hexafluoropropane, and finally deacetylating to obtain the 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane. The synthetic route does not need catalytic hydrogenation or nitration, and compared with the existing route for synthesizing 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, the synthetic route provided by the invention has the advantages of higher safety, more environmental friendliness, lower production cost and basically equivalent yield, thereby being more suitable for industrial mass production.
Antimalarial Benzimidazole Derivatives Incorporating Phenolic Mannich Base Side Chains Inhibit Microtubule and Hemozoin Formation: Structure-Activity Relationship and in Vivo Oral Efficacy Studies
Dziwornu, Godwin Akpeko,Coertzen, Dina,Leshabane, Meta,Korkor, Constance M.,Cloete, Cleavon K.,Njoroge, Mathew,Gibhard, Liezl,Lawrence, Nina,Reader, Janette,Van Der Watt, Mari?tte,Wittlin, Sergio,Birkholtz, Lyn-Marie,Chibale, Kelly
supporting information, p. 5198 - 5215 (2021/05/06)
A novel series of antimalarial benzimidazole derivatives incorporating phenolic Mannich base side chains at the C2 position, which possess dual asexual blood and sexual stage activities, is presented. Structure-activity relationship studies revealed that the 1-benzylbenzimidazole analogues possessed submicromolar asexual blood and sexual stage activities in contrast to the 1H-benzimidazole analogues, which were only active against asexual blood stage (ABS) parasites. Further, the former demonstrated microtubule inhibitory activity in ABS parasites but more significantly in stage II/III gametocytes. In addition to being bona fide inhibitors of hemozoin formation, the 1H-benzimidazole analogues also showed inhibitory effects on microtubules. In vivo efficacy studies in Plasmodium berghei-infected mice revealed that the frontrunner compound 41 exhibited high efficacy (98% reduction in parasitemia) when dosed orally at 4 × 50 mg/kg. Generally, the compounds were noncytotoxic to mammalian cells.
Paracetamol and other acetanilide analogs as inter-molecular hydrogen bonding assisted diamagnetic CEST MRI contrast agents
Chakraborty, Subhayan,Peruncheralathan,Ghosh, Arindam
, p. 6526 - 6534 (2021/02/21)
Paracetamol and a few other acetanilide derivatives are reported as a special class of diamagnetic Chemical Exchange Saturation Transfer (diaCEST) MRI contrast agents, that exhibit contrast only when the molecules form inter-molecular hydrogen bonding mediated molecular chains or sheets. Without the protection of the hydrogen bonding their contrast producing labile proton exchanges too quickly with the solvent to produce any appreciable contrast. Through a number of variable temperature experiments we demonstrate that under the conditions when the hydrogen bond network breaks and the high exchange returns back, the contrast drops quickly. The well-known analgesic drug paracetamol shows 12% contrast at a concentration of 15 mM at physiological conditions. With the proven safety track-record for human consumption and appreciable physiological contrast, paracetamol shows promise as a diaCEST agent forin vivostudies.
Ethyl 2-Cyano-2-(2-nitrobenzenesulfonyloxyimino) Acetate (ortho-NosylOXY)-Mediated Double Beckmann Rearrangement of Ketoximes under Microwave Irradiation: A Mechanistic Perception
Dev, Dharm,Kalita, Tapasi,Mondal, Tanmay,Mandal, Bhubaneswar
, p. 1427 - 1435 (2021/01/04)
A method for Beckmann rearrangement using ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino) acetate (o-NosylOXY) under microwave irradiation is reported. Ketoximes (19 examples) are converted to the corresponding amides/lactams with 69–97% yields in ～10 minutes without any Lewis acid or co-catalyst. This is an example of halogen-free organocatalytic Beckmann rearrangement. Nuclear magnetic resonance (NMR)- and high-resolution mass spectrometry (HRMS)-based detailed mechanistic investigation suggest that o-NosylOXY acts as an initiator. Such initiators are reported before based on density functional theory (DFT) calculations. However, we report here the HRMS signatures of two transient intermediates, the nitrilium ion and the nitrilium ion's dimeric species. Rigorous NMR-based investigation of the reaction mechanism is performed. Our results indicate that the reported Beckmann rearrangement proceeds via two consecutive rearrangements. (Figure presented.).
The mechanism of organic radical oxidation catalysed by gold nanoparticles
Denisov, Sergey A.,Mostafavi, Mehran,Shcherbakov, Viacheslav
, p. 26494 - 26500 (2021/12/13)
Metal nanoparticles can catalyze reactions involving organic free radicals. From the first studies focused on the catalytic reduction of water by free radicals until today, the catalytic oxidation of organic radicals has not received attention. In this work, we present the results on the catalytic activity of gold nanoparticles in the oxidation of 2-propanol to acetone and acetanilide hydroxylation during water radiolysis. A detailed reaction mechanism of α-hydroxyisopropyl radical oxidation is discussed, explaining the increase in acetone formation by ca. 340% in the presence of gold nanoparticles. In the case of acetanilide hydroxylation in the presence of nanoparticles, a strong effect of oxygen in the reaction mechanism was observed: The increase in the oxygen concentration from 0 to 1.22 mM leads to a 40-fold decrease in hydroxylation product formation. This observation is unexpected since, in the absence of gold nanoparticles, oxygen stimulates hydroxylation reactions. We propose that in the presence of both oxygen and nanoparticles, oxygen attaches first to acetanilide OH-Adducts, and then nanoparticles catalyze the oxidation of peroxyl type radicals, which does not lead to the formation of hydroxylation products.
An Environmentally Benign, Catalyst-Free N?C Bond Cleavage/Formation of Primary, Secondary, and Tertiary Unactivated Amides
Kumar, Vishal,Dhawan, Sanjeev,Girase, Pankaj Sanjay,Singh, Parvesh,Karpoormath, Rajshekhar
, p. 5627 - 5639 (2021/11/11)
Herein, we report an operationally simple, cheap, and catalyst-free method for the transamidation of a diverse range of unactivated amides furnishing the desired products in excellent yields. This protocol is environmentally friendly and operates under extremely mild conditions without using any promoter or additives. Significantly, this strategy has been implied in the chemoselective synthesis of a pharmaceutical molecule, paracetamol, on a gram-scale with excellent yield. We anticipate that this universally applicable strategy will be of great interest in drug discovery, biochemistry, and organic synthesis.
Copper-free Sandmeyer-type Reaction for the Synthesis of Sulfonyl Fluorides
Zhong, Tao,Pang, Meng-Ke,Chen, Zhi-Da,Zhang, Bin,Weng, Jiang,Lu, Gui
supporting information, p. 3072 - 3078 (2020/04/10)
A copper-free Sandmeyer-type fluorosulfonylation reaction is reported. Utilizing Na2S2O5 and Selectfluor as the sulfur dioxide and fluorine sources, respectively, aryldiazonium salts were transformed into sulfonyl fluorides. The one-pot direct synthesis of sulfonyl fluorides from aromatic amines was also realized via in situ diazotization. The practicality of this method was demonstrated by the broad functional group tolerance, gram-scale synthesis, and late-stage fluorosulfonylation of natural products and pharmaceuticals.
An organocatalytic C-C bond cleavage approach: A metal-free and peroxide-free facile method for the synthesis of amide derivatives
Vodnala, Nagaraju,Gujjarappa, Raghuram,Polina, Saibabu,Satheesh, Vanaparthi,Kaldhi, Dhananjaya,Kabi, Arup K.,Malakar, Chandi C.
supporting information, p. 20940 - 20944 (2020/12/31)
A facile organocatalytic approach has been devised towards the synthesis of amide derivatives using 1,3-dicarbonyls as easily available acyl-sources under peroxide-free reaction conditions. This transformation was accomplished by the cleavage of the C-C bond in the presence of TEMPO as an organocatalyst and excludes the use of transition-metals and harsh reaction conditions. A broad range of substrates with diverse functional groups were well tolerated and delivered the products in high yields.
