- Capture of Reactive Monophosphine-Ligated Palladium(0) Intermediates by Mass Spectrometry
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A long-sought-after reactive monophosphine-ligated palladium(0) intermediate, Pd0L (L = phosphine ligand), was detected for the first time from the activation of the Buchwald precatalyst with base. The detection was enabled using desorption electrospray ionization mass spectrometry (DESI-MS) in combination with online reaction monitoring. The subsequent oxidative addition of Pd0L with aryl halide and C-N coupling with amine via reductive elimination was also probed using DESI-MS.
- Zheng, Qiuling,Liu, Yong,Chen, Qinghao,Hu, Meihong,Helmy, Roy,Sherer, Edward C.,Welch, Christopher J.,Chen, Hao
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Read Online
- BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
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A versatile metal- and base-free direct reductive amination of aldehydes with amines using formic acid as a reductant under the catalysis of inexpensive BF3·Et2O has been developed. A wide range of primary and secondary amines and diversely substituted aldehydes are compatible with this transformation, allowing facile access to various secondary and tertiary amines in high yields with wide functional group tolerance. Moreover, the method is convenient for the late-stage functionalization of bioactive compounds and preparation of commercialized drug molecules and biologically relevant N-heterocycles. The procedure has the advantages of simple operation and workup and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger. Mechanistic studies reveal the involvement of imine activation by BF3and hydride transfer from formic acid.
- Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
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supporting information
p. 5205 - 5211
(2021/07/29)
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- Combined KOH/BEt3Catalyst for Selective Deaminative Hydroboration of Aromatic Carboxamides for Construction of Luminophores
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The selective catalytic C-N bond cleavage of amides into value-added amine products is a desirable but challenging transformation. Molecules containing iminodibenzyl motifs are prevalent in pharmaceutical molecules and functional materials. Here we established a combined KOH/BEt3 catalyst for deaminative hydroboration of acyl-iminodibenzyl derivatives, including nonheterocyclic carboxamides, to the corresponding amines. This novel transition-metal-free methodology was also applied to the construction of Clomipramine and luminophores.
- Li, Jinshan,Wang, Jiali,Yang, Jianguo,Yao, Wubing,Zhong, Aiguo
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supporting information
p. 8086 - 8090
(2020/11/03)
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- Sodium Triethylborohydride-Catalyzed Controlled Reduction of Unactivated Amides to Secondary or Tertiary Amines
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The first transition-metal-free catalytic protocol for controlled reduction of amide functions using cheap and bench-stable hydrosilanes as reducing agents has been established. By altering the hydrosilane and solvent, the new method enables the selective cleavage of unactivated C-O bonds in amides and allows the C-N bonds to selectively break via the deacylated cleavage. Overall, this novel process may offer a versatile alternative to current methodologies employing stoichiometric metal systems for the controlled reduction of carboxamides.
- Yao, Wubing,He, Lili,Han, Deman,Zhong, Aiguo
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- Sodium Triethylborohydride-Catalyzed Controlled Reduction of Unactivated Amides to Secondary or Tertiary Amines
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The first transition-metal-free catalytic protocol for controlled reduction of amide functions using cheap and bench-stable hydrosilanes as reducing agents has been established. By altering the hydrosilane and solvent, the new method enables the selective cleavage of unactivated C-O bonds in amides and allows the C-N bonds to selectively break via the deacylated cleavage. Overall, this novel process may offer a versatile alternative to current methodologies employing stoichiometric metal systems for the controlled reduction of carboxamides.
- Yao, Wubing,He, Lili,Han, Deman,Zhong, Aiguo
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p. 14627 - 14635
(2019/12/02)
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- Method for selective reducing reaction of tertiary aryl amide and borane
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The present invention relates to a method for a selective reducing reaction of a tertiary aryl amide and borane. A tertiary amine product is prepared by the reducing reaction of a tertiary aryl amidederivative and a cheap and easily available organoboron reagent under mild conditions under the convenient catalysis of a non-transition metal compound sodium triethylborohydride used as a catalyst for the first time. Compared with traditional methods, the method of the method generally has the advantages of wide universality of a substrate, low cost and easy availability of the catalyst, and simplicity in reaction operation. The selective reducing reaction of the tertiary aryl amide compound and the organoboron reagent under the catalysis of the transition metal catalyst is realized for the first time, and a brand new "green" reaction strategy is provided for the laboratory preparation or industrial production of tertiary arylamine products.
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Paragraph 0061-0064
(2019/10/23)
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- Tailored Cobalt-Catalysts for Reductive Alkylation of Anilines with Carboxylic Acids under Mild Conditions
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The first cobalt-catalyzed hydrogenative N-methylation and alkylation of amines with readily available carboxylic acid feedstocks as alkylating agents and H2 as ideal reductant is described. Combination of tailor-made triphos ligands with cobalt(II) tetrafluoroborate significantly improved the efficiency, thus promoting the reaction under milder conditions. This novel protocol allows for a broad substrate scope with good functional group tolerance, even in the presence of reducible alkenes, esters, and amides.
- Liu, Weiping,Sahoo, Basudev,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
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supporting information
p. 11673 - 11677
(2018/09/10)
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- Novel nonmetal catalytic bidirectional selective reduction method of tertiary aromatic amide
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The invention relates to a novel effective bidirectional selective environment-friendly method for hydrosilation reduction of tertiary aromatic amide and an organic silicon reagent. The method comprises the following steps: selecting a nonmetal catalytic system, and selectively preparing a secondary or tertiary organic amine compound by successively catalyzing tertiary aromatic amide and cheap PHMS or triethoxysilane under a mild condition. By adopting the method, the bidirectional selective reduction of the tertiary aromatic amide is realized by innovatively utilizing an electronic effect and steric hindrance difference of an organic silicon reagent at first time, so that a brand new strategy is provided for the reduction of amide and derivative of the amide, the defects of the traditional method that the substrate functional group is poor in compatibility, the production cost is high and the like can be overcome, and the application prospect of the amine compound prepared in industrial production or laboratory is promising.
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Paragraph 0074; 0075; 0076; 0077
(2017/10/22)
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- Deoxygenation of tertiary amine N-oxides under metal free condition using phenylboronic acid
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A simple and efficient method for the deoxygenation of amine N-oxides to corresponding amines is reported using the green and economical reagent phenylboronic acid. Deoxygenation of N,N-dialkylaniline N-oxides, trialkylamine N-oxides and pyridine N-oxides were achieved in good to excellent yields. The reduction susceptible functional groups such as ketone, amide, ester and nitro groups are well tolerated with phenylboronic acid during the deoxygenation process even at high temperature. In addition, an indirect method for identification and quantification of tert-amine N-oxide is demonstrated using UV–Vis spectrometry which may be useful for drug metabolism studies.
- Gupta, Surabhi,Sureshbabu, Popuri,Singh, Adesh Kumar,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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supporting information
p. 909 - 913
(2017/02/15)
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- Esters, Including Triglycerides, and Hydrogen as Feedstocks for the Ruthenium-Catalyzed Direct N-Alkylation of Amines
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Triglycerides are used for the direct N-alkylation of amines with molecular hydrogen for the first time. A broad range of interesting and industrially relevant secondary and tertiary amines are obtained in the presence of an in situ formed Ru/Triphos complex. Notably, plant oil can be efficiently applied in this single-step process. Moreover, a variety of other methyl esters can be used as N-alkylation agents in the presence of hydrogen for the synthesis of more advanced building blocks.
- Adam, Rosa,Cabrero-Antonino, Jose R.,Junge, Kathrin,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 11049 - 11053
(2016/10/13)
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- Enhanced Reactivity of Aerobic Diimide Olefin Hydrogenation with Arylboronic Compounds: An Efficient One-Pot Reduction/Oxidation Protocol
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A catalyst-free and efficient method for simultaneous olefin hydrogenation and oxidation of arylboronate esters to phenols with hydrazine hydrate and molecular oxygen is presented. The process is based on the utilization of a readily available Lewis acidic arylboron compound, which evades common problems associated with the catalyst-free aerobic hydrogenation of olefins with diimide. Using an operationally simple procedure, the protocol smoothly delivers phenol derivatives and various alkanes in excellent yields with remarkable functional group compatibility. The method allows the reaction to be scaled up to 1 g of the starting materials.
- Santra, Surojit,Guin, Joyram
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supporting information
p. 7253 - 7257
(2015/11/25)
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- Convenient Reductive Methylation of Amines with Carbonates at Room Temperature
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Methylation of amines is a fundamental and commonly used reaction in organic synthesis. Many methods are known including various reductive methylations using formaldehyde, formic acid, or carbon dioxide in the presence of reductants. However, several of these methods suffer from limited substrate scope and chemoselectivity because of the different nucleophilicities of substrates. In this respect, the combination of carbonates and hydrosilanes is a valuable methylation source in the presence of Pt-based catalysts. This highly tunable method allows for methylation of both aromatic and aliphatic amines, and chemoselective methylation of aminoalcohols and diamines. Notably, the in situ-formed catalyst can also be used for the reduction of carbonates to methanol at room temperature. Mechanistic insights on intermediates formed during the reaction pathway were obtained by using ESI mass spectrometry.
- Li, Yuehui,Sorribes, Iván,Vicent, Cristian,Junge, Kathrin,Beller, Matthias
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p. 16759 - 16763
(2015/11/16)
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- Catalytic methylation of aromatic amines with formic acid as the unique carbon and hydrogen source
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A novel methodology is presented for the direct methylation of amines, using formic acid as a unique source of carbon and hydrogen. Based on ruthenium(II) catalysts, the formation of the N - CH3group proceeds via an efficient formylation/transfer hydrogenation pathway.
- Savourey, Solne,Lefvre, Guillaume,Berthet, Jean-Claude,Cantat, Thibault
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supporting information
p. 14033 - 14036
(2015/02/19)
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- Methylation of secondary amines with dialkyl carbonates and hydrosilanes catalysed by iron complexes
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Methylation of secondary amines was achieved using dimethyl carbonate or diethyl carbonate as the C1 source under the catalysis of well-defined half-sandwich iron complexes bearing an N-heterocyclic carbene ligand. The reaction proceeded under mild conditions in the presence of hydrosilanes as the reductants, and the amines were obtained with good to excellent isolated yields. This journal is
- Zheng, Jianxia,Darcel, Christophe,Sortais, Jean-Baptiste
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supporting information
p. 14229 - 14232
(2014/12/11)
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- General catalytic methylation of amines with formic acid under mild reaction conditions
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A general catalytic protocol for the methylation of amines has been developed applying, for the first time, formic acid as the C1 building block and silanes as reducing agents. A broad range of aromatic and aliphatic, both primary and secondary, amines has been converted to the corresponding tertiary amines including [N-13C]-labelled drugs in good to excellent yields under mild conditions. Methylation made easy: A general catalytic protocol for the methylation of amines has been developed applying, for the first time, formic acid as the C1 building block and silanes as reducing agents. A broad range of aromatic and aliphatic, both primary and secondary, amines has been converted to the corresponding tertiary amines, including [N-13C]-labelled drugs, in good to excellent yields at mild conditions (see scheme; dppp=(1,3-bis(diphenylphosphino)propane)).
- Sorribes, Ivan,Junge, Kathrin,Beller, Matthias
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supporting information
p. 7879 - 7883
(2014/07/07)
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- Selective methylation of amines with carbon dioxide and H2
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Put a label on it: Carbon dioxide with H2 is shown to be an efficient and selective methylation reagent for aromatic and aliphatic amines (see scheme; acac=acetylacetonate, triphos = 1,1,1- tris(diphenylphosphanylmethyl)ethane). A variety of functionalized amines including 13C-labelled drugs were obtained with good yields and functional-group tolerance. Copyright
- Li, Yuehui,Sorribes, Ivan,Yan, Tao,Junge, Kathrin,Beller, Matthias
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supporting information
p. 12156 - 12160
(2013/12/04)
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- Magnetite (Fe3O4) silica based organic-inorganic hybrid copper(ii) nanocatalyst: A platform for aerobic N-alkylation of amines
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A magnetically recoverable, efficient and selective copper based nanocatalyst has been synthesised via covalent grafting of 2-acetylthiophene on a silica coated magnetic nanosupport followed by metallation with copper acetate. The obtained organic-inorganic hybrid nanomaterial has been characterized by electron microscopy techniques (SEM and TEM with EDS), XRD, VSM, FT-IR and AAS. The catalytic performance of the novel nano-catalyst is evaluated in the active transformation of various aromatic amines to industrially-important alkylated amines. The nanocomposites afford high turnover frequency and high selectivity for amines under aerobic conditions. Furthermore, the heterogeneous nature of the catalyst allows easy magnetic recovery and regeneration, which makes the present protocol highly beneficial to address the industrial needs and environmental concerns.
- Sharma, Rakesh K.,Monga, Yukti,Puri, Aditi,Gaba, Garima
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p. 2800 - 2809
(2013/10/08)
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- Identification of 4-(N,N-Dipropylamino)Benzaldehyde as a Potent, Reversible Inhibitor of Mouse and Human Class I Aldehyde Dehydrogenase
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As the physiologic roles for the different classes of aldehyde dehydrogenase (ALDH) enzymes are elucidated, the identification of specific, reversible inhibitors becomes of great pharmacologic interest. Previous structure-function studies identified dialkylamino substituted benzaldehyde compounds as a novel class of reversible inhibitors of class I ALDH. To examine further structural requirements for inhibition, we tested a series of 4-(N,N-dialkylamino)benzaldehyde analogs as inhibitors of propanal oxidation by mouse liver and human erythrocyte class I ALDH. 4-(N,N-dipropylamino)benzaldehyde (DPAB) was identified as the most potent, reversible inhibitor of propanal oxidation by class I ALDH in spectrophotometric enzyme assays. In kinetic studies, DPAB showed mixed-type inhibition with respect to the aldehyde substrates propanal, phenylacetaldehyde, benzaldehyde, and aldophosphamide. DPAB exhibited uncompetitive inhibition with respect to the cofactor NAD. Inhibition constants (Ki) for DPAB, estimated from Dixon plots, were 10 nM (propanal) and 77 nM (phenylacetaldehyde) for mouse ALDH and 3 nM (propanal) and 70 nM (phenylacetaldehyde) for human ALDH. These Ki values are 100-fold lower than those reported for class I specific inhibitors. At low ( 75 percent, whereas inhibition of benzaldehyde (32 percent) and phenylacetaldehyde (19 percent) oxidation was reduced markedly. These results indicate that DPAB exhibits potent, reversible inhibition of mouse and human class I ALDH. The degree of inhibition was highly dependent on the structure of the aldehyde substrate.
- Russo, James,Chung, Song,Contreras, Kristi,Lian, Brian,Lorenz, Jon,Stevens, David,Trousdell, Wendy
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p. 399 - 406
(2007/10/03)
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- New experiments in the reductive N-alkylation and N-peralkylation of aromatic amines
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Some secondary and primary aromatic amines were variously N-alkylated and N-peralkylated by the aldehyde-sodium borohydride procedure in acidic aqueous solution. The procedure lends itself to the α-mono and α,α1-dideuterium labelling of the new N-substituent(s).
- Verardo,Giumanini,Strazzolini
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p. 609 - 627
(2007/10/02)
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- Preparation of hexenedioic acid diesters
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Hexene-1,6-dioates, readily hydrogenated into adipates (which in turn are conveniently hydrolyzed into adipic acid), are prepared by reacting carbon monoxide, an alcohol and at least one dichlorobutene, in the presence of a catalytically effective amount of palladium or a palladium compound and no more than two equivalents (relative to the dichlorobutene) of a tertiary amine reaction promoter; in an alternate embodiment, the tertiary amine and the dichlorobutene are first converted into a quaternary ammonium chloride intermediate.
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- Environmental Effects on Dye Aggregation - Effect of Electrolytes on Metachromasy of Thiazine Dyes
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The aggregation properties of a series of thiazine dyes have been studied spectrophotometrically.It has been found that the aggregating power of cations increases in the orders: K(+) > Na(+) > Li(+) and Ba(2+) > Ca(2+) > Mg(2+), which has been explained on the basis of the concept of free volume.Increase in salt concentration causes an increase in the screening factor or the effective dielectric constant of the microscopic dye/solvent system and thus promotes aggregation.The effect of anions on the aggregation of dyes increases in the order: PO4(3-) > SO4(2-) > Cl(-), whereas deaggregation increases as (C4H9)4N(+) > (C3H7)4N(+) > (C2H5)4N(+) > (CH3)4N(+).
- Bose, Himangshu S.
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p. 652 - 655
(2007/10/02)
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- Diphenylamino and indolyl substituted pyromellitides
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This invention relates to 3,7-bis(disubstituted aminophenyl- or indolyl)-3,7-bis(diphenylamino)pyromellitides, 3,5-bis(disubstituted aminophenyl- or indolyl)-3,5-bis(diphenylamino)pyromellitides and mixtures thereof useful as color formers, particularly in carbonless duplicating and thermal marking systems, which are prepared by the interaction of 2,5-bis(disubstituted aminophenyl- or indolyl)carbonyl-1,4-benzenedicarboxylic acids or 2,4-bis(disubstituted aminophenyl- or indolyl)carbonyl-1,5-benzenedicarboxylic acids and mixtures thereof with diphenylamines.
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- Indolyl phthalide compounds
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3-Aryl-3-indolylphthalides, 3-aryl-3-pyrrolylphthalides and 3-aryl-3-carbazolylphthalides prepared by interaction of the appropriate 2-(heteroaryl)carbonylbenzoic acid and the appropriate phenylamine, and 3,3-bis(indolyl)phthalides prepared by the interaction of the appropriate 2-(indolyl)carbonylbenzoic acid and the appropriate indole are useful as color formers in pressure-sensitive carbonless duplicating systems, thermal marking systems and hectographic copying systems.
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- Heteroarylphthalides
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3-Aryl-3-indolylphthalides, 3-aryl-3-pyrrolylphthalides and 3-aryl-3-carbazolylphthalides prepared by interaction of the appropriate 2-(heteroaryl)carbonylbenzoic acid and the appropriate phenylamine, and 3,3-bis(indolyl)-phthalides prepared by the interaction of the appropriate 2-(indolyl)carbonylbenzoic acid and the appropriate indole are useful as color formers in pressure-sensitive carbonless duplicating systems, thermal marking systems and hectographic copying systems.
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- Phthalide compounds, processes and marking systems
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3-Aryl-3-indolylphthalides, 3-aryl-3-pyrrolylphthalides and 3-aryl-3-carbazolylphthalides prepared by interaction of the appropriate 2-(heteroaryl)carbonylbenzoic acid and the appropriate phenylamine, and 3,3-bis(indolyl)phthalides prepared by the interaction of the appropriate 2-(indolyl)carbonylbenzoic acid and the appropriate indole are useful as color formers in pressure-sensitive carbonless duplicating systems, thermal marking systems and hectographic copying systems.
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