- Studies of Collectors. VIII. The Flotation of the Gallium Ion with Oxine-Type Surfactants
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Oxine-type surfactants(5-alkanoyl-8-quinolinol, RnOx, n=2, 8, 12, 18) and R12OOx were prepared and used as ion-flotation collectors.Cu2+, Fe3+, Zn2+, and Pb2+ were floated with R12Ox around a neutral pH, and the selective removal of Cu2+ from the mixture of these four metal ions was observed at pH 1.0.The floatability of Ga3+ was also high around the neutral pH, and the selective Ga3+ flotation from an Al3+(100 ppm)-Ga3+(20 ppm) mixture was observed by using R8Ox in the pH regions of 3-4 and 10-13.3 (0.2 M NaOH soln), while R12Ox did not float the Ga3+ so much at pH 10-13.3.By the addition of a small amount of RnPy to the R12Ox or by the solvent sublation, an effective flotation of Ga3+ was observed in the pH range of 10-13.3.The Ga3+ flotation was superior to the Ga3+ extraction in pH 2-4.However, in a strong alkaline region the flotability was lower than the extractability.
- Koide, Yoshifumi,Hokonohara, Hisashi,Jinnai, Kuniaki,Yamada, Kimiho
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- Synthesis, characterization, crystallographic studies of 5-acetyl-8-hydroxyquinoline and their chalcone derivatives
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An efficient, easy and one pot synthesis for the Friedel-Craft acetylation reaction of quinolines was developed. The reaction between 8-hydroxyquinoline and acetyl/benzoyl chloride in nitrobenzene immediately flocculates as yellow precipitate. On further
- Vagish,Kumara, Karthik,Lokanath,Kumar, K. Ajay,Chandrasherkar
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p. 1609 - 1613
(2020/07/30)
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- Photorelease of phosphates: Mild methods for protecting phosphate derivatives
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We have developed a new photoremovable protecting group for caging phosphates in the near UV. Diethyl 2-(4-hydroxy-1-naphthyl)- 2-oxoethyl phosphate (14a) quantitatively releases diethyl phosphate upon irradiation in aq MeOH or aq MeCN at 350 nm, with quantum efficiencies ranging from 0.021 to 0.067 depending on the solvent composition. The deprotection reactions originate from the triplet excited state, are robust under ambient conditions and can be carried on to 100% conversion. Similar results were found with diethyl 2-(4-methoxy-1-naphthyl)-2-oxoethyl phosphate (14b), although it was significantly less efficient compared with 14a. A key step in the deprotection reaction in aq MeOH is considered to be a Favorskii rearrangement of the naphthyl ketone motif of 14a,b to naphthylacetate esters 25 and 26. Disruption of the ketone-naphthyl ring conjugation significantly shifts the photoproduct absorption away from the effective incident wavelength for decaging of 14, driving the reaction to completion. The Favorskii rearrangement does not occur in aqueous acetonitrile although diethyl phosphate is released. Other substitution patterns on the naphthyl or quinolin-5-yl core, such as the 2,6-naphthyl 10 or 8-benzyloxyquinolin-5-yl 24 platforms, also do not rearrange by aryl migration upon photolysis and, therefore, do not proceed to completion. The 2,6-naphthyl ketone platform instead remains intact whereas the quinolin-5-yl ketone fragments to a much more complex, highly absorbing reaction mixture that competes for the incident light.
- Senadheera, Sanjeewa N.,Yousef, Abraham L.,Givens, Richard S.
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supporting information
p. 2038 - 2054
(2014/11/07)
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- NEUROPROTECTIVE AND NEURO-RESTORATIVE IRON CHELATORS AND MONOAMINE OXIDASE INHIBITORS AND USES THEREOF
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8-Hydroxy-quinoline derivatives and 8-ethers, 8-esters, 8-carbonates, 8-acyloxymethyl, 8- phosphates, (phosphoryloxy)methyl, and 8-carbamates derivatives thereof are described that exhibit iron chelation, neuroprotective, neurorestorative, apoptotic and/or selective MAO-AB inhibitory activities.
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- Synthesis of 8-hydroxyquinoline chalcones: Trans configuration, intramolecular hydrogen bonds, bromination, and antifungal activity
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Nine (8-Hydroxyquinolin-5-yl)-arylpropenones were synthesized and their structures demonstrated by IR and NMRspectroscopy. These molecules showed transconfiguration and strong intramolecular hydrogen bonding; in the IR spectra of 5-formyl-8-hydroxyquinoline, 5-acetyl-8-hydroxyquinoline, 1-(8-hydroxyquinolin-5-yl)-3-phenylprop-2-en-1-one and 3-(8-hydroxyquinolin-5- yl)-1-phenylprop-2-en-1-one in CHCl3, besides the known intermolecular hydrogen band (～3180 cm-1), we identified the intramolecular hydrogen band OH...N (3460 cm-1); the hydrogen bond peaks shifted to low frequency in proton-donor solutions such as phenol and acetic acid (with respect to 8-hydroxyquinoline) and the bonds were broken in trifluoroacetic acid solutions, due to OH protonation; the apolar solvent CCl4 and electrophilic substituents in position 5 in the quinoline ring, limited the formation of the intermolecular hydrogen bonds and, therefore, shifted the ～3460 cm-1 intramolecular hydrogen band to lower frequencies and made it stronger and sharper. The bromination of 3-(8-hydroxyquinolin-5-yl)-1-(4- tolyl) prop-2-en-1-one occurred on the activated quinoline fragment, producing monobromo and tetrabromo derivatives, instead of bromination on the aliphatic double bond. Three chalcones tested showed strong antifungal activity in vitro.
- Marrugo-Gonzalez, Alonso J.,Orlov, Valerie D.,Fernandez-Maestre, Roberto
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p. 1287 - 1291
(2013/03/29)
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- PROCESS FOR PREPARING ISOMERS OF CARMOTEROL
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A process for preparing a compound of formula (III) comprising condensing an oxiranyl compound of formula (I) with an amine of formula (II) or a salt thereof wherein: R1 is a group selected from alkyl, aryl, allyl, alkoxy, cycloalkyl, heterocyclic, alkenyl, benzocycloalkyl, aralkyl, haloarylalkyl, heteroaralkyl, haloalkyl, alkoxyaralkyl, substituted silyl and benzyl; and R2 is hydrogen, optionally substituted silyl or optionally substituted benzyl. Formula (I), (II) and (III): There is also described a process for preparing (R,R)-carmoterol from compound (III).
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