1207-20-1Relevant articles and documents
Copper-catalyzed formal transfer hydrogenation/deuteration of aryl alkynes
Sloane, Samantha E.,Reyes, Albert,Vang, Zoua Pa,Li, Lingzi,Behlow, Kiera T.,Clark, Joseph R.
supporting information, p. 9139 - 9144 (2020/11/30)
A copper-catalyzed reduction of alkynes to alkanes and deuterated alkanes is described under transfer hydrogenation and transfer deuteration conditions. Commercially available alcohols and silanes are used interchangeably with their deuterated analogues as the hydrogen or deuterium sources. Transfer deuteration of terminal and internal aryl alkynes occurs with high levels of deuterium incorporation. Alkyne-containing complex natural product analogues undergo transfer hydrogenation and transfer deuteration selectively, in high yield. Mechanistic experiments support the reaction occurring through a cis-alkene intermediate and demonstrate the possibility for a regioselective alkyne transfer hydrodeuteration reaction.
Commutative reduction of aromatic ketones to arylmethylenes/alcohols by hypophosphites catalyzed by Pd/C under biphasic conditions
Guyon, Carole,Baron, Marc,Lemaire, Marc,Popowycz, Florence,Métay, Estelle
, p. 2088 - 2095 (2014/03/21)
An efficient method is reported to reduce aromatic ketones selectively into arylmethylenes or alcohols with hypophosphites and Pd/C, depending on the selected conditions. This study could represent a promising alternative to the classical uses of standard hydrides or molecular hydrogen involved in reduction and deoxygenation procedures.
Sterically expanded CGC catalysts: Substituent effects on ethylene and α-olefin polymerization
Chai, Jianfang,Abboud, Khalil A.,Miller, Stephen A.
, p. 9139 - 9147 (2013/07/27)
Several analogues of the sterically expanded constrained geometry catalyst Me2Si(η1-C29H36) (η1-N-tBu)ZrCl2·OEt2 (2) were synthesized to assess the effect on branching and molecular weight for ethylene homopolymerization. Catalysts based on tetramethyltetrahydrobenzofluorene (TetH), ethylTetH, t-butylTetH, and octamethyloctahydrodibenzofluorenyl (OctH) bearing a diphenylsilyl bridge were prepared and characterized: Me 2Si(η5-C21H22) (η1-N-tBu)ZrCl2 (3); Me2Si(η 5-C23H26)(η1-N-tBu)ZrCl 2 (4); and Me2Si(η5-C25H 30)(η1-N-tBu)ZrCl2 (5); Me 2Si(η5-C21H22) (η1-N-tBu)ZrMe2 (6); and Ph2Si(η 5-C29H36)(η1-N-tBu)ZrCl 2 (7). Complexes 4, 5, 6, and 7 were characterized by X-ray crystallography and displayed η5 hapticity to the carbon ring in each case, in contrast to 2. In comparison to 2, complexes 3, 4, 5, and 7 (in combination with methylaluminoxane = MAO) showed diminished branching, higher molecular weight, and higher polydispersity indices for obtained ethylene homopolymers. While 4/MAO produced the greatest molecular weight polymers, no branching was observed. Reactivity ratios were determined for the copolymerization of ethylene and 1-decene with 2/MAO. A value of r ethylene = 14.9 and an exceedingly high value of r1-decene = 0.49 were found - in line with previous reports of this catalyst's unusual affinity for α-olefins.
Synthesis and liquid crystal phase behaviour of 2-(4-cyanophenyl)-7-n-alkylfluorenes: Luminescent mesogens
Boardman, Frederick H.,Dunmur, David A.,Grossel, Martin C.,Luckhurst, Geoffrey R.
, p. 60 - 61 (2007/10/03)
A new range of nematic liquid crystals containing the 2-phenylfluorene core has been prepared which may be considered as a model system for luminescent mesogens, which have potential interest as new display materials.
Synthesis of Fluorene Based Fatty Acids for Use as Membrane Probes
Anjaneyulu, P. S. R.,Lala, Anil K.
, p. 1067 - 1068 (2007/10/02)
Synthesis of two fatty acid analogs (IV and VII) incorporating fluorene as a fluorescent chromophore is reported.Preliminary fluorescence studies indicate that these compounds can be used as fluorescent probes for depth-dependent studies in membranes.
Structure-activity relationships of (arylalkyl)imidazole anticonvulsants: Comparison of the (fluorenylalkyl)imidazoles with nafimidone and denzimol
Robertson,Krushinski,Beedle,Leander,Wong,Rathbun
, p. 1577 - 1586 (2007/10/02)
A recently discovered and structurally distinct class of antiepileptic drugs is the (arylalkyl)imidazoles. Two independently discovered representatives of this class, denzimol (α-[4-(2-phenylethyl)phenyl]-1H-imidazole-1-ethanol) and nafimidone (2-(1H-imidazol-1-yl)-1-(2-naphthalenyl)ethanone), are undergoing clinical evaluation. Our structure-activity relationship (SAR) studies revealed that in addition to the naphthalenyl and phenethylphenyl aryl moieties of nafimidone and denzimol, respectively, fluorenyl, benzo[b]thienyl, and benzofuranyl aryl groups provided several highly active (arylalkyl)imidazole anticonvulsants. These structurally diverse aryl moieties, and comparable anticonvulsant activities, lend credence to the hypothesis that the pharmacophore of this class of anticonvulsants is the alkylimidazole portion of the molecule, with the lipophilic aryl portion enabling penetration of the blood-brain barrier. The authors focused their SAR studies on the (fluorenylalkyl)imidazole series. A representative compound from this series is 1-(9H-fluoren-2-yl)-2-(1H-imidazol-1-yl)ethanone. This agent was twice as potent as nafimidone in inhibiting maximal electroshock seizures in mice (po ED50's = 25 and 56 mg/kg, respectively) and considerably less toxic in the rat (po LD50's = 4550 and 504 mg/kg, respectively). The tertiary alcohol α-(9H-fluoren-2-yl)-α-methyl-1H-imidazole-1-ethanol) was as potent as denzimol in mice (po ED50's = 10 and 12 mg/kg, respectively). This series of imidazole anticonvulsants was highly selective; while many compounds displayed potent antielectroshock activity, little or no activity was observed against pentylenetetrazole-induced clonic seizures or in the horizontal screen test for ataxia. All active compounds that we tested in this series, as well as denzimol and nafimidone, potentiated hexobarbital-induced sleeping time in mice, probably by imidazole-mediated inhibition of cytochrome P-450. The SAR's for the anticonvulsant activity and the sleeping time potentiation were similar. The propensity of these (arylalkyl)imidazole anticonvulsants to interact strongly with cytochrome P-450 and thereby impair the metabolism of other antiepileptic drugs may severely limit their clinical utility as anticonvulsants.
Synthesis, molecular and electron transport properties of 2-alkyltrinitrofluoren-9-ones
Ong, Beng S.,Keoshkerian, Barkev,Martin, Trevor I.,Hamer, Gordon K.
, p. 147 - 152 (2007/10/02)
2-Alkyltrinitrofluoren-9-ones 2 were conveniently synthesized by controlled nitration of 2-alkylfluoren-9-ones 5 with a mixture of red fuming HNO3, and concentrated H2SO4 at 0-25 deg C.The precursors 5 were derived from the corresponding 2-acylfluorenes by appropriate reduction of the acyl function, followed by base-catalysed O2-oxidation at the C-9 position.The regiochemistry of nitration was interesting: with a sterically bulky substituent in 5, nitration occurred at C-4, -5, and -7 positions, affording 2-alkyl-4,5,7-trinitrofluoren-9-one in over 35percent yield; on the other hand, 5 with a primary alkyl function underwent nitration predominantly at C-3, -5, and 7- positions.By virtue of its alkyl function, 2-alkyltrinitrofluoren-9-one 2 displayed better solubility and polymer compatibility characteristics than its non-alkylated analog, TNF.However, the charge transfer interactions of 2 with electron donors were weaker than those of TNF, despite the fact that they both have the same electron affinity.Both 2 and TNF exhibited good electron transport properties in poly(N-vinylcarbazole) matrices.
REDUCTION WITH LITHIUM IN ETHYLENEDIAMINE. PART V. POLYCYCLIC AROMATIC KETONES
Mejer, Stanislaw,Pacut, Ryszard
, p. 453 - 459 (2007/10/02)
Reduction of acetyl derivatives of naphthalene, diphenyl, fluorene and phenanthrene with Li-EDA, THF is described.
