- C2-substituted quinazolinone derivatives exhibit A1 and/or A2A adenosine receptor affinities in the low micromolar range
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Antagonists of the adenosine receptors (A1 and A2A subtypes) are widely researched as potential drug candidates for their role in Parkinson's disease-related cognitive deficits (A1 subtype), motor dysfunction (A2A subtype) and to exhibit neuroprotective properties (A2A subtype). Previously the benzo-α-pyrone based derivative, 3-phenyl-1H-2-benzopyran-1-one, was found to display both A1 and A2A adenosine receptor affinity in the low micromolar range. Prompted by this, the α-pyrone core was structurally modified to explore related benzoxazinone and quinazolinone homologues previously unknown as adenosine receptor antagonists. Overall, the C2-substituted quinazolinone analogues displayed superior A1 and A2A adenosine receptor affinity over their C2-substituted benzoxazinone homologues. The benzoxazinones were devoid of A2A adenosine receptor binding, with only two compounds displaying A1 adenosine receptor affinity. In turn, the quinazolinones displayed varying degrees of affinity (low micromolar range) towards the A1 and A2A adenosine receptor subtypes. The highest A1 adenosine receptor affinity and selectivity were favoured by methyl para-substitution of phenyl ring B (A1Ki = 2.50 μM). On the other hand, 3,4-dimethoxy substitution of phenyl ring B afforded the best A2A adenosine receptor binding (A2AKi = 2.81 μM) among the quinazolinones investigated. In conclusion, the quinazolinones are ideal lead compounds for further structural optimization to gain improved adenosine receptor affinity, which may find therapeutic relevance in Parkinson's disease-associated cognitive deficits and motor dysfunctions as well as exerting neuroprotective properties.
- Pieterse, Lianie,Terre'Blanche, Gisella,van der Walt, Mietha M.
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supporting information
(2020/06/08)
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- Palladium (0)-catalyzed C(sp2)-H oxygenation with carboxylic acids
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Palladium (0)-catalyzed Ortho-benzoxylation of the sp2 C–H bond of arylbenzoxazinones with carboxylic acid is reported. With benzoxazinone as directing group, the reaction went smoothly under the benign condition and gave the desired product wi
- Gong, Ai-Jun,Li, Xu-Qin,Vu, Huu-Manh,Yong, Jia-Yuan
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supporting information
(2020/02/15)
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- Recyclable Heterogeneous Palladium-Catalyzed Carbonylative Cyclization of 2-Iodoanilines with Aryl Iodides Leading to 2-Arylbenzoxazinones
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A highly efficient and practical heterogeneous palladium-catalyzed carbonylative coupling of 2-iodoanilines with aryl iodides has been developed. The reaction occurs smoothly in toluene at 110 °C with N, N -diisopropylethylamine as base under carbon monoxide (5 bar) and offers a general and powerful tool for the construction of various valuable 2-arylbenzoxazinones with excellent atom-economy, high functional group tolerance, good to high yields, and easy recyclability of the palladium catalyst. The reaction is the first example of heterogeneous palladium-catalyzed carbonylative coupling for the preparation of diverse 2-arylbenzoxazinones from commercially easily available 2-iodoanilines and aryl iodides.
- Cai, Mingzhong,Huang, Bin,Xu, Zhaotao,Zhou, Zebiao
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p. 581 - 590
(2020/02/13)
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- Oxidative NHC catalysis for base-free synthesis of benzoxazinones and benzoazoles by thermal activated NHCs precursor ionic liquid catalyst using air as oxidant
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A reusable thermal activated NHC precursor ionic liquid catalyst ([BMIm]2[WO4]) has been prepared and developed for the synthesis of nitrogen-containing heterocycles such as benzoxazinones and benzoazoles through imines activation. [BMIm]2[WO4] exhibited the good activity for the base-free condensation and oxidative NHC catalysis tandem under air atmosphere. The catalyst can be recovered and reused for at least five runs in gram scale synthesis without any decrease in catalytic activity. Furthermore, the control experiments demonstrated that the reaction involved formation of aromatic aldimines, NHC-catalyzed oxidative formation of imidoyl azoliums and intramolecular cyclization to generate the product.
- Guan, Jiali,Liu, Wei,Liu, Yuchen,Song, Zhibin,Tao, Duan-Jian,Yan, Jieying,Yuan, Jian-Jun,Zhou, Youkang
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- Palladium-Catalyzed Olefination of 4H-Benzo[d][1,3]oxazin-4-one Derivatives with Activated Alkenes via Preferential Cyclic Imine-N-Directed Aryl C-H Activation
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A palladium-catalyzed chelation-assisted selective ortho C-H bond olefination of biologically active 4H-benzo[d][1,3] oxazin-4-one derivatives with activated olefins has been achieved. The products are obtained in good yields with high regio- and stereose
- Panja, Subir,Maity, Srabani,Majhi, Biju,Ranu, Brindaban C.
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p. 5777 - 5786
(2019/08/30)
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- One-Pot Synthesis of 2-Arylbenzoxazinones from 2-Arylindoles with (Diacetoxyiodo)benzene as the Sole Oxidant
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A series of synthetically interesting 2-arylbenzoxazinones was prepared from 2-arylindoles by an efficient oxidative reaction mediated by (diacetoxyiodo)benzene [PhI(OAc) 2 ] and assisted by water. PhI(OAc) 2 was used as the sole oxi
- Shang, Xian-Xing,Vu, Huu-Manh,Li, Xu-Qin
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supporting information
p. 377 - 383
(2017/10/30)
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- Silver-Mediated Synthesis of 4H-Benzoxazin-4-ones by Intramolecular Decarboxylative O-Acylation Reactions with α-Oxocarboxylic Acid
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The first example of an intramolecular decarboxylative acylation reaction for the synthesis of 4H-benzoxazin-4-one derivatives has been described. The silver-mediated reaction has a broad substrate scope and provides a mild and rapid approach to the corre
- Bharathimohan, Kuppusamy,Ponpandian, Thanasekaran,Jafar, Ahamed A.
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p. 2806 - 2813
(2017/05/29)
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- RETRACTED ARTICLE: Palladium-Catalyzed Decarboxylative Selective Acylation of 4H-Benzo[d][1,3]oxazin-4-one Derivatives with α-Oxo Carboxylic acids via Preferential Cyclic Imine-N-Directed Aryl C-H Activation
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The benzoxazine scaffolds are of much interest as they are found in a large array of natural products and pharmaceutical drugs with diverse activities. We have developed a palladium-catalyzed decarboxylative selective mono- and bis-acylation of 4H-benzo[d
- Majhi, Biju,Kundu, Debasish,Ghosh, Tubai,Ranu, Brindaban C.
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p. 283 - 295
(2016/02/16)
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- Selective Oxidative Decarbonylative Cleavage of Unstrained C(sp3)-C(sp2) Bond: Synthesis of Substituted Benzoxazinones
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A transition metal (TM)-free practical synthesis of biologically relevant benzoxazinones has been established via a selective oxidative decarbonylative cleavage of an unstrained C(sp3)-C(sp2) bond employing iodine, sodium bicarbonate, and tbutyl hydroperoxide in DMSO at 95 °C. Control experiments and Density Functional Theory (DFT) calculations suggest that the reaction involves a [1,5]H shift and extrusion of CO gas as the key steps. The extrusion of CO has also been established using PMA-PdCl2.
- Verma, Ajay,Kumar, Sangit
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supporting information
p. 4388 - 4391
(2016/10/11)
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- Catalytic aza-wittig reaction of acid anhydride for the synthesis of 4H-benzo[d][1,3]oxazin-4-ones and 4-benzylidene-2-aryloxazol-5(4H)-ones
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Compared to the aza-Wittig reaction of aldehydes, ketones, amides, and esters, the aza-Wittig reaction of acid anhydride was always overlooked, which should be an important part of Wittig reactions. Here, the aza-Wittig reaction of anhydride and catalytic aza-Wittig reaction of anhydride were both developed with high yields, which provides an efficient method to synthesize of 4H-benzo[d][1,3]oxazin-4-ones and 4-benzylidene-2-aryloxazol-5(4H)-ones. The strategy of copper-catalyzed reduction of phosphine oxide was used and found effective for this transformation. Additionally, the one-pot catalytic aza-Wittig reaction of carboxylic acids was achieved. Furthermore, NMR experiments and Hammett plot recorded the process of catalytic aza-Wittig reaction of anhydride, which provides direct proof that the copper-catalyzed reduction of waste phosphine oxide is the key step in this transformation.
- Wang, Long,Xie, Yi-Bi,Huang, Nian-Yu,Yan, Jia-Ying,Hu, Wei-Min,Liu, Ming-Guo,Ding, Ming-Wu
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p. 4010 - 4016
(2016/07/06)
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- TBHP/CoCl2-mediated intramolecular oxidative cyclization of N-(2-formylphenyl)amides: An approach to the construction of 4H-3,1-benzoxazin-4-ones
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The intramolecular oxidative cyclization of N-(2-formylphenyl)amides has been realized through an oxidative C(sp2)-O(sp2) bond-forming reaction between an aldehyde carbon and amide oxygen. This new strategy, which uses tert-butyl hydroperoxide (TBHP) as an oxidant and CoCl2 as the catalyst, allows for the efficient Co-catalyzed synthesis of useful benzoxazin-4-one derivatives and features readily available starting materials and mild reaction conditions. The intramolecular cyclization of N-(2-formylphenyl)amides has been realized through an oxidative C(sp2)-O(sp2) bond-forming reaction between an aldehyde carbon and amide oxygen. This new strategy, which uses tert-butyl hydroperoxide (TBHP) as the oxidant and CoCl2 as the catalyst, allows for the efficient Co-catalyzed synthesis of useful benzoxazin-4-one derivatives.
- Yu, Junchao,Zhang-Negrerie, Daisy,Du, Yunfei
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p. 562 - 568
(2016/02/18)
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- Copper catalyzed C-N bond formation/C-H activation: Synthesis of aryl 4H-3,1-benzoxazin-4-ones
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We have developed a practical and efficient synthesis of 2-phenyl-4H-benzo[d][1,3]oxazine-4-one derivatives through copper catalyzed tandem reaction of 2-iodobenzoic acid with arylmethanamines under aerobic conditions. Compared to the literature methods toward the synthesis of 2-phenyl-4H-benzo[d][1,3]oxazine-4-one, the synthetic method reported in this Letter has broad substrate scope, mild reaction condition, and uses an inexpensive catalyst.
- Munusamy, Sathishkumar,Venkatesan, Sathesh,Sathiyanarayanan, Kulathu Iyer
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p. 203 - 205
(2015/02/02)
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- Synthesis of 2-Aryl-4H-3,1-Benzoxazin-4-ones: A Class of α-Chymotrypsin Inhibitors
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Twenty one derivatives of 2-aryl-4H-3,1-benzoxazin-4-one were synthesized and their potential therapeutically significance and structureactivity relationship were tested against α-chymotrypsin. Majority of synthesized compounds showed significant in vitro α-chymotrypsin inhibitory properties having IC50values in the range of 5.42 ± 1.66 - 41.27 ± 1.33 μM, whereas standard inhibitor chymostatin have IC50 value 7.13 ± 1.06 μM. In the present series compounds 2-(2-fluorophenyl)-4H-3,1-benzoxazin-4-one (3h), 2-(2-bromophenyl)-4H-3,1- benzoxazin-4-one (3n) and 2-(1-naphthyl)-4H-3, 1-benzoxazin-4-one (3t) with IC50values 7.22 ± 0.75, 6.99 ± 0.29 and 5.42 ± 1.66 μM, respectively were found to be most active members of series, even better than standard inhibitor a-chymostatin.
- Khan, Zulfiqar Ali,Afzal, Noshaba,Hussain, Zaib,Naqvi, Syed Ali Raza,Bari, Ayesha,Shahzad, Sohail Anjum,Yar, Muhammad,Mahmood, Nasir,Bukhari, Shazia Anwer,Mansha, Asim,Zahoor, Ameer Fawad,Khan, Abdur Rahman,Ahmad, Matloob
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p. 4561 - 4565
(2014/12/10)
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- Pd-catalyzed intramolecular aerobic oxidative C-H amination of 2-aryl-3-(arylamino)quinazolinones: Synthesis of fluorescent indazolo[3,2-b]quinazolinones
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A palladium-catalyzed intramolecular aerobic oxidative C-H amination of 2-aryl-3-(arylamino)quinazolinones has been developed, providing a variety of substituted indazolo[3,2-b]quinazolinone derivatives in moderate to excellent yields. Preliminary mechani
- Yang, Weiguang,Chen, Jiuxi,Huang, Xiaobo,Ding, Jinchang,Liu, Miaochang,Wu, Huayue
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supporting information
p. 5418 - 5421
(2015/02/19)
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- One-pot approach to 2-arylbenzoxazinone derivatives from 2-alkynylanilines using copper-mediated tandem reactions
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In this study, we describe a one-pot method to obtain a variety of 2-arylbenzoxazinones and N-benzoyl anthranilic acid by using a copper catalyst and molecular oxygen as oxidants. This protocol involves tandem cyclization and oxidative processes of 2-alkynylanilines to afford significant motifs in synthetic and medicinal chemistry with moderate yields. We also demonstrated that combining the Sonogashira coupling and the developed method realized the synthesis of 2-arylbenzoxazinones derivatives from commercially available 2-iodoanilines and terminal acetylenes.
- Yamashita, Mitsuaki,Iida, Akira
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p. 5746 - 5751
(2015/03/30)
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- Copper-mediated oxidative tandem reactions with molecular oxygen: Synthesis of 2-arylbenzoxazinone derivatives from indoles
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We developed an efficient method for the transformation of indoles by utilizing a copper catalyst and molecular oxygen as the oxidant. The transformation involves a tandem oxidative process of 2-arylindoles. Our reaction afforded a variety of N-benzoyl an
- Yamashita, Mitsuaki,Iida, Akira
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supporting information
p. 2991 - 2993
(2014/05/06)
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- Synthesis and antimicrobial activity of 2-Aryl-4H-3,1-benzoxazin-4-ones
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Twenty derivatives of 2-aryl-4H-3,1-benzoxazin-4-one synthesized and their potential therapeutically significance tested against two strains of Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and four strains of Gram negative bacteria (Shigella flexnari, Escherichia coli, Salmonella typhi and Pseudomonas aeruginsoa) by agar well diffusion method. The 2-(3-nitrophenyl)-4H-3,1-benzoxazin-4-one (3f) recorded significant antibacterial activity against Bacillus subtilis whereas 2-(4-bromophenyl)-4H-3, 1-benzoxazin-one (3o) exhibited weak antibacterial activity against Staphylococcus aureus. Further 2-(2-methylphenyl)-4H-3,1-benzoxazin-4-one (3b) showed significant activity against Shigella Flexnari, Escherichia coli, Pseudomonas aeruginsoa and Salmonella typhi. The antibacterial activity of synthesized derivatives of 2-aryl-4H-3,1-benzoxazin-4-one was compared to reference standard antibiotics amoxycillin, streptomycin, kanamycin and ciprofloxacin. The present study revealed that 2-aryl-4H-3,1-benzoxazin-4-ones possess good bactericidal activity against a panel of bacteria causing common bacterial diseases and therefore opens the possibility of finding latest clinically useful antibacterial compounds. The synthesized compounds were characterized by 1H NMR, EI, FT-IR and elemental analysis.
- Khan, Zulfiqar Ali,Naqvi, Syed Ali Raza,Shahzad, Sohail Anjum,Mahmood, Nasir,Yar, Muhammad,Zahoor, Ameer Fawad
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p. 152 - 156
(2013/02/22)
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- Facile synthesis and herbicidal evaluation of 2-Aryl-4H-3, 1-benzoxazin-4-ones
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The present work deals with the synthesis of 4H-3,1-benzoxazin-4-ones carrying an aryl functional group at position-2. Synthesized compounds tested for herbicidal activity at three different doses (500 μg/mL, 50 μg/mL and 5μg/mL). Most of the compounds exhibited significant herbicidal activity against Lemna aequinocitalis welv. at higher dose (500 μg/mL). Among the tested compounds 2-phenyl-4H-3,1-benzoxazin-4-one (3a) and 2-(3-chlorophenyl)- 4H-3,1-benzoxazin-4- one (3l) completely inhibited the plant growth at 500 and 50 μg/mL concentrations. All the synthetic compounds were characterized by FT-IR, 1H NMR, EI-MS and elemental analysis.
- Hussain, Zaib,Khan, Zulfiqar Ali,Naqvi, Syed Ali Raza,Shahzad, Sohail Anjum,Yar, Muhammad,Hussain, Abdullah Ijaz,Chatha, Shahzad Ali Shahid,Mahmood, Nasir,Khan, Khalid Mohammed
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p. 449 - 455
(2013/07/27)
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- Oxidation of 2-arylindoles for synthesis of 2-arylbenzoxazinones with oxone as the sole oxidant
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A novel and efficient method for the oxidation of 2-arylindoles to synthesize 2-arylbenzoxazinones utilizing oxone as the sole oxidant has been developed. The reaction tolerates a wide range of functional groups and allows quick and atom-economical assembly of a variety of valuable 2-arylbenzoxazinones in high yields.
- Lian, Xiao-Li,Lei, Hao,Quan, Xue-Jing,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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supporting information
p. 8196 - 8198
(2013/09/12)
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- Kinetics and mechanism of the base-catalyzed oxygenation of 1H-2-phenyl-3-hydroxy-4-oxoquinolines in DMSO/H2O
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The oxygenation of 4′-substituted 1H-2-phenyl-3-hydroxy-4- oxoquinolines (PhquinH2) in a DMSO/H2O (50/50) solution leads to the cleavage products at the C2-C3 bond in about 75% yield at room temperature. The oxygenation, deduced from the product compositions, has two main pathways, one proceeding via an endoperoxide leading to CO-release, and the other through a 1,2-dioxetane intermediate without CO-loss. The reaction is specific base-catalyzed and the kinetic measurements resulted in the rate law -a...?[PhquinH2]/a...?t=kOH - [OH-] [PhquinH2] [O2]. The rate constant, activation enthalpy, and entropy at 303.16 K are as follows: kOH-=(2.42±0.03)×103mol -2L2s-1; ΔG?=73. 13±4.02 kJ mol-1; ΔH?=70.60±4. 04 kJ mol-1; ΔS?=-28±2 J mol -1 K-1. The reaction fits a Hammett linear free energy relationship for 4′-substituted substrates, and electron-releasing groups make the oxygenation reaction faster (ρ=-0.258). The EPR spectrum of the reaction mixtures showed the presence of the organic radical 1H-2-phenyl-3-oxyl-4-oxoquinoline and superoxide ion due to single electron transfer from the carbanion to dioxygen. The pathway via 1,2-dioxetane could be proved by chemiluminescence measurements.
- Czaun, Miklós,Speier, Gábor,Kaizer, József,El Bakkali-Taheri, Nadia,Farkas, Etelka
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p. 6666 - 6672
(2013/07/26)
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- Phl(OAc)2-mediated one-pot synthesis of benzoxazinones from anthranilic acids and aromatic aldehydes
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A novel way to synthesise 2-aryl-4H-benzo[d][1,3]oxazin-4-ones has been developed by the cyclisation of Schiff bases with (diacetoxyiodo)benzene. The salient features of this new protocol which starts from an anthranilic acid and an aromatic aldehyde, are
- Xie, Yuanyuan,Wang, Suping
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experimental part
p. 123 - 126
(2012/09/22)
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- Synthesis of 3h-quinazolin-4-ones and 4h-3,1-benzoxazin-4-ones via benzylic oxidation and oxidative dehydrogenation using potassium iodide-tert-butyl hydroperoxide
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A simple and elegant method for benzylic activation was demonstrated employing the potassium iodide/tert-butyl hydrogen peroxide catalytic system. This methodology was further extended for the synthesis of biologically important heterocycles namely, 3H-quinazolin-4-ones and 4H-3,1-benzoxazin-4-ones including mecloqualone and etaqualone which are important quinazolinone-based drugs used for the treatment of insomnia in good yields.
- Kumar, R. Arun,Maheswari, C. Uma,Ghantasala, Satheesh,Jyothi,Reddy, K. Rajender
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p. 401 - 410
(2011/04/18)
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- A new synthesis of 2-substituted 4H-3,1-benzoxazin-4-ones by cyanuric chloride cyclodehydration of N-benzoyl- and N-acylanthranilic acids
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A new and a convenient method for the synthesis of aryl- and alkyl-2-substituted 4H-3,1-benzoxazin-4-ones by cyclodehydration of N-benzoyl- and N-acylanthranilic acid by cyanuric chloride is described.
- Khajavi, Mohammad S.,Shariat, Seyed M.
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p. 1159 - 1165
(2007/10/03)
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- The base-catalyzed oxygenation of quinoline derivatives
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The base-catalyzed oxygenation of 1H-2-phenyl-3-hydroxy-4-oxoquinoline leads to cleavage products derived from either an endoperoxide or a 1,2-dioxetan intermediate. A persistent 1H-2-phenyl-3-oxy-4-oxoquinoline radical could also be detected by EPR in the reaction mixture.
- Czaun, Miklós,Speier, Gábor
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p. 5961 - 5963
(2007/10/03)
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