- Merging Annulation with Ring Deconstruction: Synthesis of (E)-3-(2-Acyl-1 H-benzo[ d]imidazol-4-yl)acrylaldehyde Derivatives via I2/FeCl3-Promoted Dual C(sp3)-H Amination/C-N Bond Cleavage
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An unprecedented I2/FeCl3-promoted cascade reaction of aryl methyl ketones with 8-aminoquinolines for the convenient synthesis of (E)-3-(2-acyl-1H-benzo[d]imidazol-4-yl)acrylaldehydes was developed by merging annulation with ring deconstruction. This novel strategy unlocked the new reactivity of 8-aminoquinolines and provided an attractive platform for the ring opening of unactivated N-heteroaromatic compounds. Preliminary mechanistic investigation suggested that dual C(sp3)-H amination/C-N bond cleavage were key reaction steps. Furthermore, late-stage modification of the obtained products successfully delivered pyrazole and isoxazole derivatives, increasing the practicability and application potential of this methodology in organic synthesis.
- Xu, Cheng,Yin, Guodong,Jia, Feng-Cheng,Wu, Yan-Dong,Wu, An-Xin
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supporting information
p. 2559 - 2564
(2021/04/13)
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- 8-amino-6-methoxyquinoline—tetrazole hybrids: Impact of linkers on antiplasmodial activity
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A new series of compounds was prepared from 6-methoxyquinolin-8-amine or its N-(2-aminoethyl) analogue via Ugi-azide reaction. Their linkers between the quinoline and the tert-butyltetrazole moieties differ in chain length, basicity and substitution. Compounds were tested for their antiplasmodial activity against Plasmodium falciparum NF54 as well as their cytotoxicity against L-6-cells. The activity and the cytotoxicity were strongly influenced by the linker and its substitution. The most active compounds showed good activity and promising selectivity.
- Dolensky, Johanna,Hochegger, Patrick,Kaiser, Marcel,M?ser, Pascal,Saf, Robert,Seebacher, Werner,Weis, Robert
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- Uncatalyzed, on water oxygenative cleavage of inert C-N bond with concomitant 8,7-amino shift in 8-aminoquinoline derivatives
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Oxygenative cleavage of an inert CAr-NH2 bond with concomitant 1,2 amine migration in 8-aminoquinoline derivatives is reported in water at room temperature. The reaction is highly atom- and step-economical as both C- and N-containing fragments of the C-N bond cleavage are incorporated into the target molecule and is effected without the need for N-oxide. The reaction is scalable to gram level, and the products are useful as electrophilic partners for coupling reactions, ligands in catalysis and bioactive compounds.
- Botla, Vinayak,Pilli, Navyasree,Malapaka, Chandrasekharam
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supporting information
p. 1735 - 1742
(2019/04/08)
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- Visible Light-Promoted Photocatalytic C-5 Carboxylation of 8-Aminoquinoline Amides and Sulfonamides via a Single Electron Transfer Pathway
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An efficient photocatalytic method was developed for the remote C5-H bond carboxylation of 8-aminoquinoline amide and sulfonamide derivatives. This methodology uses in situ generated ?CBr3 radical as a carboxylation agent with alcohol and is further extended to a variety of arenes and heteroarenes to synthesize the desired carboxylated product in moderate-to-good yields. The reaction proceeding through a single electron transfer pathway was established by a control experiment, and a butylated hydroxytoluene-trapped aryl radical cation intermediate in high-resolution mass spectrometry was identified.
- Sen, Chiranjit,Sahoo, Tapan,Singh, Harshvardhan,Suresh, Eringathodi,Ghosh, Subhash Chandra
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p. 9869 - 9896
(2019/08/20)
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- Synthesis of primaquine glyco-conjugates as potential tissue schizontocidal antimalarial agents
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Primaquine (PQ) is the only drug used to prevent relapse of malaria due to P. vivax and P. ovale, by eradicating the dormant liver form of the parasite (hypnozoites). The side-effects associated with PQ limits is uses in treatment of malaria. To overcome the premature oxidative deamination and to increase the life span of drug in the biological system, the novel glyco-conjugates of PQ were synthesized by coupling of primaquine with hexoses in phosphate buffer. The saccharide part of the hybrid molecules thought to direct the drug to the liver, where hypnozoites resides. All the synthesized compounds were fully characterized and evaluated for their radical curative activities. The three compounds viz glucoside (15a), galactoside (15b) and mannoside (15c) with high activity were tested for their activity in rhesus monkeys where the most active compound 15b showed twofold activity (100% radical curative activity at 1.92?mmol/kg) than the standard drug PQ diphosphate (3.861?mmol/kg). It is proposed that results from these studies may be advantageous to develop a new potent tissue schizonticide antimalarial compound.
- Azad, Chandra S.,Saxena, Mridula,Siddiqui, Arif J.,Bhardwaj, Jyoti,Puri, Sunil K.,Dutta, Guru P.,Anand, Nitya,Saxena, Anil K.
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p. 254 - 261
(2017/07/13)
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- 5-Position-selective C-H trifluoromethylation of 8-aminoquinoline derivatives
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We developed a copper-catalyzed 5-position-selective C-H trifluoromethylation of 8-aminoquinoline derivatives. The reaction proceeded with high functional group tolerance under mild conditions. In the case of quinolines with an amide, carbamate, urea, or sulfonamide group at the 8-position of quinoline moieties, a radical scavenger experiment indicated that the reaction proceeded via a radical pathway. The protecting group of an 8-amidoquinoline derivative could be removed by hydrolysis. On the other hand, the trifluoromethylation of 8-aminoquinolines was also promoted by other Lewis acids as well as a copper catalyst and proceeded even in the presence of a radical scavenger. These results indicated that the trifluoromethylation of 8-aminoquinolines proceeded via a Friedel-Crafts-type reaction. Interestingly, the copper salt works as either a catalyst for the formation of a CF3 radical or a Lewis acid to promote a Friedel-Crafts-type reaction, depending on the substrate.
- Kuninobu, Yoichiro,Nishi, Mitsumi,Kanai, Motomu
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supporting information
p. 8092 - 8100
(2016/09/09)
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- Metal-free synthesis of N-fused heterocyclic iodides via C-H functionalization mediated by tert-butylhydroperoxide
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Direct, regioselective and metal-free synthesis of fused N-heterocyclic iodides is reported. This regioselective C-H functionalization is mediated by tert-butylhydroperoxide (TBHP), via dual activation of molecular iodine and a heterocyclic substrate, resulting in the in situ generation of electrophilic iodine species (I+), and free radical(s) tBuO? or tBuOO?, driving the iodination reaction.
- Sharma, Krishna K.,Patel, Dhananjay I.,Jain, Rahul
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supporting information
p. 15129 - 15132
(2015/10/12)
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- Aryl-8-azabicyclo [3.2.1] octanes for the treatment of depression
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The present invention includes compounds of formula I wherein A, X, n, Ar1, and Ar2 are defined as set forth herein. These compounds may be used to treat depression. The invention also includes formulations containing these compounds, and methods for making and using compounds of this invention.
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- 8-Aminoquinolines as anticoccidials - Part III
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Analogues of the antimalarial pentaquine, 1, in which the nature of the side-chain on the 8-amino position was varied, were prepared and evaluated for anticoccidial activity both in vitro and in vivo. Specifically, both the inter-nitrogen distance and the nature of the terminal amino group were investigated. Novel analogues of equal or improved efficacy in vitro and in vivo to pentaquine were discovered.
- Armer, Richard E.,Barlow, Jacqueline S.,Chopra, Narinder,Dutton, Christopher J.,Greenway, David H.J.,Greenwood, Sean D.W.,Lad, Nita,Shaw, Jonothan,Thompson, Adrian P.,Thong, Kam-Wah,Tommasini, Ivan
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p. 2425 - 2430
(2007/10/03)
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- Bromo-6-methoxy-8-aminoquinolines: Preparation and 13C-NMR assignments
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Preparation of all possible monobromo-6-methoxy-8-aminoquinolines is reported. These materials provided an opportunity to assess the effect of bromine substitution on 13C-NMR chemical shift patterns. An explanation of the isomerization of 5-bromo-6-methoxy-8-acetamidoquinoline to 7-bromo-6-methoxy-8-aminoquinoline during hydrolysis is presented.
- McChesney,Sarangan,Hufford
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p. 1854 - 1856
(2007/10/02)
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