- A copper-catalyzed oxidative coupling reaction of arylboronic acids, amines and carbon dioxide using molecular oxygen as the oxidant
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A Cu-catalyzed oxidative coupling reaction of arylboronic acids, amines and carbon dioxide is described for the first time in this paper. The reaction tolerates a wide range of functional groups, providing a convenient protocol for the synthesis of various O-aryl carbamates. The successful development of the transformation was enabled by the use of BF3·OEt2 as the promoter and molecular oxygen as the oxidant. Mechanistic studies suggested that the CuII carbamato complex is involved in the catalytic transformation.
- Xiong, Wenfang,Qi, Chaorong,Guo, Tianzuo,Zhang, Min,Chen, Kai,Jiang, Huanfeng
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supporting information
p. 1642 - 1645
(2017/06/05)
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- METHOD OF IMPROVING COGNITION AND SOCIAL BEHAVIOR IN HUMANS HAVING DEFICITS THEREIN DUE TO NEURODEGENERATIVE DISORDERS AND COMPOUNDS AND COMPOSITIONS THEREFOR
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A β1-ADR agonist prodrug compound, which is hydrolysable in vivo to release a β1-ADR agonist compound, and which prodrug compound contains a group which imparts greater lipophilicity and CNS bioavailability to the prodrug compound relative to the β1-ADR agonist compound.
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Paragraph 0142
(2016/08/03)
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- Kinetic study on aminolysis of phenyl 2-pyridyl carbonate in acetonitrile: Effect of intramolecular h-bonding interaction on reactivity and reaction mechanism
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Second-order rate constants (kN) have been measured spectrophotometrically for the reactions of phenyl 2- pyridyl carbonate (6) with a series of cyclic secondary amines in MeCN at 25.0 ± 0.1 °C. The Bronsted-type plot for the reaction of 6 is linear with βnuc = 0.54, which is typical for reactions reported previously to proceed through a concerted mechanism. Substrate 6 is over 103 times more reactive than 2-pyridyl benzoate (5), although the reactions of 6 and 5 proceed through the same mechanism. A combination of steric hindrance, inductive effect and resonance contribution is responsible for the kinetic results. The reactions of 6 and 5 proceed through a cyclic transition state (TS) in which H-bonding interactions increase the nucleofugality of the leaving group (i.e., 2-pyridiniumoxide). The enhanced nucleofugality forces the reactions of 6 and 5 to proceed through a concerted mechanism. In contrast, the corresponding reaction of 4-nitrophenyl 2-pyridyl carbonate (7) proceeds through a stepwise mechanism with quantitative liberation of 4-nitrophenoxide ion as the leaving group, indicating that replacement of the 4-nitrophenoxy group in 7 by the PhO group in 6 changes the reaction mechanism (i.e., from a stepwise mechanism to a concerted pathway) as well as the leaving group (i.e., from 4-nitrophenoxide to 2-pyridiniumoxide). The strong electron-withdrawing ability of the 4- nitrophenoxy group in 7 inhibits formation of a H-bonded cyclic TS. The presence or absence of a H-bonded cyclic TS governs the reaction mechanism (i.e., a concerted or stepwise mechanism) as well as the leaving group (i.e., 2-pyridiniumoxide or 4-nitrophenoxide).
- Song, Ji-Hyun,Lee, Jae-In,Um, Ik-Hwan
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p. 2081 - 2085
(2014/12/10)
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- Concerted aminolysis of diaryl carbonates: Kinetic sensitivity on the basicity of the nucleophile, nonleaving group, and nucleofuge
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The kinetics of the reactions of 4-methylphenyl, phenyl, and 4-chlorophenyl 2,4,6-trinitrophenyl carbonates (1, 2, and 3, respectively) with a series of anilines and secondary alicyclic (SA) amines has been carried out spectrophotometrically in 44 wt% ethanol-water, at 25.0°C, ionic strength 0.2 M. The BrAnsted plots (statistically corrected) for the reactions of carbonates 1-3 with anilines and SA amines were linear with slopes (βN) in the range of 0.69-0.78 and 0.45-0.48, respectively, attributed to a concerted mechanism. The negative values found for the sensitivity of log kN to the basicity of the nonleaving (βnlg) and leaving (βlg) groups are discussed. Anilines are more reactive than isobasic SA amines, probably because of the greater steric hindrance offered by the latter.
- Castro, Enrique A.,Cubillos, Maria,Iglesias, Rocio,Santos, Jose G.
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experimental part
p. 604 - 611
(2012/09/08)
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- Anionic ortho-fries rearrangement, a facile route to arenol-based mannich bases
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Phenol and 1-naphthol-based carbamates undergo the anionic ortho-Fries rearrangement to their corresponding amides. Bulky substitution at position 8 of 1-naphthol-based carbamates makes the rearrangement an exclusive reaction, even at -90 C, under a variety of conditions. The amides can be efficiently reduced to the corresponding Mannich bases. A novel route to 7-[(dialkylamino)methyl]-8- hydroxy-1-naphthaldehydes is presented.
- Assimomytis, Nikos,Sariyannis, Yiannis,Stavropoulos, Georgios,Tsoungas, Petros G.,Varvounis, George,Cordopatis, Paul
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scheme or table
p. 2777 - 2782
(2010/03/03)
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- Achieving functional group diversity in parallel synthesis: solution-phase synthesis of a library of ureas, carbamates, thiocarbamates, and amides using carbamoylimidazolium salts
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A convenient protocol for the parallel solution-phase synthesis of a library of thiocarbamates, ureas, carbamates, and amides from carbamoylimidazolium salts has been developed. The crystalline carbamoylimidazolium salts are readily synthesized from secon
- Grzyb, Justyna A.,Batey, Robert A.
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p. 5279 - 5282
(2008/12/21)
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- AZAARENE DERIVATIVES
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A compound represented by the general formula: wherein X1 represents a nitrogen atom or a group represented by the formula -CR10=; X2 represents a nitrogen atom or a group represented by the formula -CR11=; Y represents an oxygen atom or the like; R1 represents a C1-6 alkoxy group, an optionally substituted C6-10 aryloxy group, a group represented by the formula -NR12aR12b or the like; R2 represents a hydrogen atom, an optionally substituted C1-6 alkyl group, or the like; R3, R4, R5, R6, R7, R8, R10 and R11 each independently represent a hydrogen atom, a halogen atom, an optionally substituted C1-6 alkyl group, or the like; R9 represents a group represented by the formula -NR16aR16b or the like; and R12a, R12b, R16a and R16b each independently represent a hydrogen atom, an optionally substituted C1-6 alkyl group, or the like, a salt thereof, or a hydrate of the foregoing.
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Page/Page column 110
(2008/06/13)
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- ortho-anisylsulfonyl as a protecting group for secondary amines: Mild Ni0-catalyzed hydrodesulfonylation
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A potentially good alternative to the tosyl group (Ts) as a protecting group for amines is N-ortho-anisylsulfonyl (Ans), which is readily cleaved under mild, Ni0-catalyzed reductive conditions (see scheme, acac = acetylacetonate). N-Anisylation of primary amines followed by alkylation and deprotection provides a route to a range of secondary amines.
- Milburn, Robert R.,Snieckus, Victor
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p. 892 - 894
(2007/10/03)
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- Kinetics and mechanism of the aminolysis of methyl 4-nitrophenyl, methyl 2,4-dinitrophenyl, and phenyl 2,4-dinitrophenyl carbonates
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The reactions of methyl 4-nitrophenyl carbonate (MNPC) with a series of secondary alicyclic amines (SAA) and quinuclidines (QUIN), methyl 2,4-dinitrophenyl carbonate (MDNPC) with QUIN and 1-(2-hydroxyethyl)piperazinium ion (HPA), and phenyl 2,4-dinitrophenyl carbonate (PDNPC) with SAA are subjected to a kinetic investigation in aqueous solution, at 25.0°C and an ionic strength of 0.2 M. By following spectrophotometrically the nucleofuge release (330-400 nm) under amine excess, pseudo-first-order rate coefficients (kobsd) are obtained. Plots of kobsd VS [amine] at constant pH are linear, with the slope (kN) being pH independent. The Broensted-type plot (log kN vs amine pKa) for the reactions of SAA with MNPC is biphasic with slopes β1 = 0.3 (high pKa region) and β2 = 1.0 (low pKa region) and a curvature center at pKa0 = 9.3. This plot is consistent with a stepwise mechanism through a zwitterionic tetrahedral intermediate (T±) and a change in the rate-determining step with SAA basicity. The Broensted plot for the quinuclidinolysis of MNPC is linear with slope βN = 0.86, in line with a stepwise process where breakdown of T± to products is rate limiting. A previous work on the reactions of SAA with MDNPC was revised by including the reaction of HPA. The Broensted plots for the reactions of QUIN and SAA with MDNPC and SAA with PDNPC are linear with slopes β = 0.51, 0.48, and 0.39, respectively, consistent with concerted mechanisms. Since quinuclidines are better leaving groups from T± than isobasic SAA, yielding a less stable T±, it seems doubtful that the quinuclidinolysis of PDNPC is stepwise, as reported.
- Castro, Enrique A.,Aliaga, Margarita,Campodonico, Paola,Santos, Jose G.
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p. 8911 - 8916
(2007/10/03)
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- Structure-reactivity correlations in the aminolysis of aryl chloroformates
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The reactions of a series of secondary alicyclic amines with 4-methylphenyl and 4-methoxyphenyl chloroformates are subjected to a kinetic investigation in water, at 25.0°C, ionic strength 0.2 M (KCI). Under amine excess, pseudo-first-order rate coefficients (kobs) are found for all reactions. Plots of kobs vs [NH] (NH is the free amine) are linear, with the slope (kN) pH independent, except the reactions of l-(2-hydroxyethyl)piperazine with both substrates at pH 6.2-7.3. The Broensted-type plots for the kN values for the aminolysis of both chloroformates are linear, with slopes ca. 0.3, which is consistent with rate-determining formation of a zwitterionic tetrahedral intermediate (T±). With the PKa and log kN data for the present reactions, together with those for the same aminolysis of phenyl and 4-nitrophenyl chloroformates, two dual parametric equations are found for log kN as a function of pKa of the nucleophile, Hammett sigma of the "nonleaving" group, and pKa of the "nonleaving" group, with coefficients βN = 0.3, ρnlg = 0.7, and βnlg = -0.2, respectively.
- Castro, Enrique A.,Ruiz, Mara G.,Santos, Jos G.
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p. 281 - 287
(2007/10/03)
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- Kinetics and mechanism of the aminolysis of phenyl and 4-nitrophenyl chloroformates in aqueous solution
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The reactions of secondary alicyclic amines with phenyl and 4- nitrophenyl chloroformates (PClF and NPClF, respectively) are subjected to a kinetic investigation in aqueous solution, 25.0 °C, ionic strength 0.2 (KCl). The reactions are followed spectropho
- Castro, Enrique A.,Ruiz, Maria G.,Salinas, Sandra,Santos, Jose G.
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p. 4817 - 4820
(2007/10/03)
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- Synthesis and anti-trypanosomal activity of novel 5-nitro-2-furaldehyde and 5-nitrothiophene-2-carboxaldehyde semicarbazone derivatives
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Several novel semicarbazones derivatives were prepared from 5-nitro-2-furaldehyde or 5-nitrothiophene-2-carboxaldehyde, and tested in vitro as potential anti-trypanosomal agents. The compounds were prepared in good to excellent yields in 2-3 steps from readily available starting materials. Some derivatives were found to be active against Trypanosoma cruzi with an activity similar to that of Nifurtimox.
- Cerecetto, Hugo,Di Maio, Rossanna,Ibarruri, Gerardo,Seoane, Gustavo,Denicola, Ana,Peluffo, Gonzalo,Quijano, Celia,Paulino, Margot
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- TRIAZOLO-1,4-DIAZEPINE DERIVATIVES AND THEIR USE IN PHARMACEUTICALS
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A triazolo-1,4-di-azepine compound of the below given formulas and a pharmacologically acceptable salt thereof are disclosed and useful in the pharmaceutical field, especially to allergic diseases. STR1 in which R1 and R2 are hydrogen or an alkyl, R3 is hydrogen or a halogen, R4 is hydrogen or an alkyl, X is--OCO--,--NHCO--,--CO--or others and Y is a cycloalkyl, a cycloalkylalkyl, an alkynyl or others.
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- α-Haloalkyl Haloformates and Related Compounds 1. A Convenient Synthesis of Carbamates via Chloromethyl Carbamates
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The preparation of carbamates under mild conditions utilizing a new class of activated carbonates (containing chloromethyl function) is described.
- Patonay, Tamas,Patonay-Peli, Erzsebet,Mogyorodi, Ferenc
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p. 2865 - 2885
(2007/10/02)
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- MORPHOLINE CARBOXAMIDES AND USE THEREOF
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1-Hydroxyphenoxy-3-ureidoethylamino-2-propanol derivatives, processes for their manufacture, pharmaceutical compositions containing them and methods of using them in the treatment of heart failure. The compounds possess cardio-selective β-adrenergic stimu
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