1,721,023 research outputs found
Carbonylation of nitrosobenzenes to carbamate esters catalyzed by palladium and cupric acetates under ambient conditions
No full textPd(OAc)2 and Cu(OAc)2 are effective catalysts for the carbonylation of RNO(R = Ph, o-tolyl, 1-naphthyl, p-Me2NC6H4) with CO and R1OH (R = Me, Et, Pr, Me2CH) at room temp. and one atm. to give RNHCOR1
Catalytic reduction of the arene ring, and other functionalities, of organic substrates using formic acid and palladium on carbon
No full textThe arene ring in a variety of compds. with functionalities which contain nitrogen is reduced in good yields using formic acid and Pd/C in methanol. Treatment of nitrobenzene with formic acid and Pd/carbon in methanol gave cyclohexylamine (53% yield) and as byproducts N-phenylcyclohexylamine (34% yield) and dicyclohexylamine (12% yield). The conditions were also applicable to azidobenzene, nitrosobenzene, aniline and azobenzene, or azobenzene oxide
Direct diacylation of Schiff bases
No full textA novel diacylation of Schiff bases occurs in the presence of catalytic amts. of Co2(CO)8 under phase-transfer catalysis conditions. E.g., treatment of PhCH:NC6H4OMe-p with CO and MeI in CH2Cl2-H2O contg. polyethylene glycol and Co(CO)8 gives 68% MeCOCHPhNAcC6H4OMe-p and 11% PhCH2NAcC6H4OMe-p
Novel nickel catalyzed conversion of 2-bromo-1-phenyl-1,3-butadiene to an α-keto lactone. An example of double carbonylation of a halodiene
No full textNi cyanide and phase transfer-catalyzed carbonylation of PhCH:CBrCH:CH2 gave methylene-α-keto lactone I in good yield; isomerization to a keto butenolide (II) occurs on silica gel. The Ni catalyst was generated by treatment of Ni(CN)2.4H2O with CO and cetyltrimethylammonium bromide in NaOH and PhMe
Stereospecific nickel- and phase-transfer-catalyzed carbonylation of vinyl bromides and chlorides
No full textNi cyanide catalyzes the carbonylation of vinyl bromides and chlorides to α,β-unsatd. acids. Thus, treatment of trans-β-bromostyrene with 6N NaOH, toluene, and catalytic quantities of cetyltrimethylammonium bromide and Ni(CN)2 for 2.5 h at 95° and one atm of CO afforded 75% trans-cinnamic acid
Highly Regioselective Thiocarbonylation of Conjugated Dienes via Palladium-Catalyzed Three-Component Coupling Reactions
No full textThree-component coupling reaction of conjugated dienes, thiols, and carbon monoxide affords an atom-economical thiocarbonylation of the dienes to give β,γ-unsatd. thioesters as the sole products. A catalyst system based on [Pd(OAc)2] and Ph3P showed excellent catalytic activity. The thiocarbonylation was performed under an atm. of carbon monoxide (400 psi) at 110 °C in CH2Cl2 for 60 h. A wide variety of thioesters were synthesized in good to excellent yields from easily accessible starting materials. The reaction is believed to proceed via a η3-allylpalladium intermediate. The thiocarbonylation, which is applicable to a wide variety of conjugated dienes, occurs in high regioselectivity, the latter dependent on the steric characteristics and stability of the η3-allylpalladium complex
Synthesis of unsaturated acids by 1,2-addition of formic acid to conjugated dienes catalyzed by palladium on carbon in the presence of mono and bidentate phosphine
No full textDi- and trisubstituted 1,3-dienes are converted to γ,δ-unsatd. acids by use of formic acid, carbon monoxide, and catalytic quantities of Pd-C/PPh3/Ph2P(CH2)4PPh2 in 1,2-dimethoxyethane. A β,γ-unsatd. acid was obtained from isoprene (a monosubstituted diene)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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