- Nonisomorphous x-ray structures of tritylnitrile and tritylisonitrile
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The crystal structures of a related series of isosteric compounds, namely tritylnitrile 1, tritylisonitrile 2, and a solid solution of tritylnitrile/tritylisonitrile 3 have been determined by single crystal X-ray diffraction. The bond lengths, angles, and
- Skodje, Kelsey M.,Hinkle, Lindsay M.,Miranda, Maria O.,Mann, Kent R.,Janzen, Daron E.
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Read Online
- I2/Li2CO3-promoted cyanation of diarylalcohols through a dual activation process
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One-step base promoted strategy for cyanation of α,α-diaryl alcohols has been developed under mild and transition metal-free conditions. This method provides a straightforward and facile way towards the synthesis of β,γ-unsaturated nitriles and α-phenylnitiriles from α-vinyl carbinols and α,α-diaryl methanols, respectively, up to 99% yield. Moreover, various azides and ethers could also be accessed from their respective nucleophiles under standard reaction conditions.
- Hu, Liangzhen,Hussain, Muhammad Ijaz,Deng, Qingfu,Liu, Qing,Feng, Yangyang,Zhang, Xiaohui,Xiong, Yan
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supporting information
p. 308 - 314
(2018/12/11)
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- Lewis Acid Catalyzed Synthesis of Cyanidophosphates
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Salts containing new cyanido(fluorido)phosphate anions of the general formula [PF6-n(CN)n]- (n=1-4) were synthesized by a very mild Lewis-acid-catalyzed synthetic protocol and fully characterized. All [PF6-n(CN)n]- (n=1-4) salts could be isolated on a preparative scale. It was also possible to detect the [PF(CN)5]- but not the [P(CN)6]- anion. The best results with respect to purity, yield, and low cost were obtained when the F-/CN- substitution reactions were carried out in ionic liquids. Cyanido(fluorido)phosphates: Salts containing [PF6-n(CN)n]- (n=1-4) ions were isolated on a preparative scale by utilizing Lewis acids (LA) catalysts under mild conditions (see equation). The best results with respect to purity, yield, and low cost were obtained when the F-/CN- substitution reactions were carried out in ionic liquids.
- Bl?sing, Kevin,Ellinger, Stefan,Harloff, J?rg,Schulz, Axel,Sievert, Katharina,T?schler, Christoph,Villinger, Alexander,Zurt?schler, Cornelia
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supporting information
p. 4175 - 4188
(2016/03/16)
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- Hydride Reduction by a Sodium Hydride-Iodide Composite
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Sodium hydride (NaH) is widely used as a Br?nsted base in chemical synthesis and reacts with various Br?nsted acids, whereas it rarely behaves as a reducing reagent through delivery of the hydride to polar π electrophiles. This study presents a series of reduction reactions of nitriles, amides, and imines as enabled by NaH in the presence of LiI or NaI. This remarkably simple protocol endows NaH with unprecedented and unique hydride-donor chemical reactivity.
- Too, Pei Chui,Chan, Guo Hao,Tnay, Ya Lin,Hirao, Hajime,Chiba, Shunsuke
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supporting information
p. 3719 - 3723
(2016/03/26)
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- The Concise Synthesis of Unsymmetric Triarylacetonitriles via Pd-Catalyzed Sequential Arylation: A New Synthetic Approach to Tri- and Tetraarylmethanes
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The selective synthesis of multiarylated acetonitriles via sequential palladium-catalyzed arylations of chloroacetonitrile is reported. The three aryl groups are installed via a Pd-catalyzed Suzuki-Miyaura cross coupling reaction followed by back-to-back C-H arylations to afford triarylacetonitriles in three steps with no over-arylation at any step. The triarylacetonitrile products can be converted into highly functionalized species including tetraarylmethanes. This new strategy provides rapid access to a variety of unsymmetrical tri- and tetraarylmethane derivatives from simple, readily available starting materials. (Chemical Presented)
- Nambo, Masakazu,Yar, Muhammad,Smith, Joel D.,Crudden, Cathleen M.
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supporting information
p. 50 - 53
(2015/07/28)
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- Efficient assembly of α-aryl and α-vinyl nitriles via iron-catalyzed ether bond activation
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A novel and practical method for the synthesis of diverse α-aryl and α-vinyl nitriles was developed via an iron-catalyzed sp3 C-O ether bond cleavage with C-C bond formation in the reaction of π-activated ethers with TMSCN.
- Fan, Xiaohui,Guo, Kun,Guan, Yong-Hong,Fu, Lin-An,Cui, Xiao-Meng,Lv, Hao,Zhu, Hong-Bo
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supporting information
p. 1068 - 1071
(2014/02/14)
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- Efficient assembly of α-aryl and α-vinyl nitriles via iron-catalyzed ether bond activation
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A novel and practical method for the synthesis of diverse α-aryl and α-vinyl nitriles was developed via an iron-catalyzed sp3 C-O ether bond cleavage with C-C bond formation in the reaction of π-activated ethers with TMSCN.
- Fan, Xiaohui,Guo, Kun,Guan, Yong-Hong,Fu, Lin-An,Cui, Xiao-Meng,Lv, Hao,Zhu, Hong-Bo
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supporting information
p. 1068 - 1071
(2015/02/18)
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- Nitrile imines: Matrix isolation, IR spectra, structures, and rearrangement to carbodiimides
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The structures and reactivities of nitrile imines are subjects of continuing debate. Several nitrile imines were generated photochemically or thermally and investigated by IR spectroscopy in Ar matrices at cryogenic temperatures (Ph-CNN-H 6, Ph-CNN-CH317, Ph-CNN-SiMe323, Ph-CNN-Ph 29, Ph3C-CNN-CPh334, and the boryl-CNN-boryl derivative 39). The effect of substituents on the structures and IR absorptions of nitrile imines was investigated computationally at the B3LYP/6-31G level. IR spectra were analyzed in terms of calculated anharmonic vibrational spectra and were generally in very good agreement with the calculated spectra. Infrared spectra were found to reflect the structures of nitrile imines accurately. Nitrile imines with IR absorptions above 2200 cm -1 have essentially propargylic structures, possessing a CN triple bond (typically PhCNNSiMe323, PhCNNPh 29, and boryl-CNN-boryl 39). Nitrile imines with IR absorptions below ca. 2200 cm-1 are more likely to be allenic (e.g., HCNNH 1, PhCNNH 6, HCNNPh 43, PhCNNCH317, and Ph3C-CNN-CPh334). All nitrile imines isomerize to the corresponding carbodiimides both thermally and photochemically. Monosubstituted carbodiimides isomerize thermally to the corresponding cyanamides (e.g., Ph-N=C=N-H 5 Ph-NH-CN 8), which are therefore the thermal end products for nitrile imines of the types RCNNH and HCNNR. This tautomerization is reversible under flash vacuum thermolysis conditions.
- Begue, Didier,Qiao, Greg Guanghua,Wentrup, Curt
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scheme or table
p. 5339 - 5350
(2012/05/20)
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- Process development and optimization for production of a potassium ion channel blocker, ICA-17043
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A scalable process for the manufacture of a potassium ion channel blocker was developed and optimized. Key features of the process include an optimized Grignard reaction, a direct cyanation of the intermediate trityl alcohol derivative, and an improved nitrile hydrolysis protocol, relative to the original acidic hydrolysis conditions, to generate the crude active pharmaceutical ingredient (API) with >95% HPLC purity. The Grignard and the cyanation reactions could be telescoped, resulting in an improved throughput compared to the original four-step process. An effective recrystallization of the API was also developed and the process scaled up to manufacture multiple batches at the pilot scale.
- Mobele, Bingidimi I.,Venkatraman, Sripathy,McNaughton-Smith, Grant,Gibb, Cameron,Ulysse, Luckner G.,Lindmark, Carl A.,Shaw, Stephen,Marron, Brian,Spear, Kerry,Suto, Mark J.
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p. 1385 - 1392
(2012/11/07)
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- Synthesis of α-aryl nitriles through B(C6F5)3-catalyzed direct cyanation of α-aryl alcohols and thiols
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Various α-aryl nitriles have been prepared in excellent yield from the corresponding α-aryl alcohols employing 3 mol % of B(C6F5)3 (1) as Lewis acid catalyst and (CH3)3SiCN (TMSCN) as cyanide source. Cyano transfer from TMSCN to alcohol proceeds within short reaction time at rt. α-Aryl thiols also produce corresponding nitriles in good to excellent yield at reflux condition.
- Rajagopal, Gurusamy,Kim, Sung Soo
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experimental part
p. 4351 - 4355
(2009/09/30)
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- Photochemistry and photophysics of triarylmethane dye leuconitriles
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The photochemical reactions of crystal violet leuconitrile (CVCN) were investigated by the means of product analysis and trapping experiments, laser flash and steady-state photolysis, and steady-state fluorescence. The influence of oxygen on the reaction was examined in detail. The photochemistry of malachite green leuconitrile (MGCN), basic fuchsin leuconitrile (BFCN), and crystal violet leucomethyl (CVMe) and leucobenzyl (CVBn), as well as triphenylacetonitrile, was studied. The results suggest ionization occurs from S1, while the di-π-methane reaction is the photochemical route from T1.
- Jarikov,Neckers
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p. 659 - 671
(2007/10/03)
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- Triarylmethyl substituted 4,5-dicyanoimidazoles as activators for Rp- diastereoselective synthesis of TpN dinucleoside methylphosphonates
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2-Triarylmethyl-4,5-dicyanoimidazoles 1-3 were synthesized and tested as activators in the methylphosphonamidite approach. TpN dinucleoside methylphosphonates generated showed diastereoselectivity of up to 8/1 (Rp/Sp). The influence of the different triarylmethyl substituents on diastereoselectivity is shown.
- Schell, Peter,Laux, Wolfgang H. G.,Engels, Joachim W.
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p. 1169 - 1174
(2007/10/03)
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- Titanium(IV) Chloride Catalyzed Cyanation of Benzylic Halides With Trimethylsilyl Cyanide
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Six sterically hindered benzylic chlorides have been substituted with cyano groups in excellent yields with trimethylsilyl cyanide and titanium tetrachloride in methylene chloride.Both monochloro substrates such as diphenylmethyl chloride and triphenylmethyl chloride and dichloro substrates such as dichlorodiphenylmethane and sym-tetraphenylethylene dichloride were studied.Because isonitriles are plausible reaction intermediates, the isomerization of trityl isonitrile by TiCl4 and by trityl tetrafluoroborate was studied at 0 and -78 deg C.Both reagents catalyze conversion to triphenylacetonitrile at 0 deg C while only trityl tetrafluoroborate is effective at -78 deg C.It was also found that trityl tetrafluoroborate reacts with trimethylsilyl cyanide in the absence of TiCl4 to give triphenylacetonitrile in 96percent yield.
- Zieger, Herman E.,Wo, Shiming
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p. 3838 - 3840
(2007/10/02)
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- Reactivity of 1,2-O-cyanoalkylidene sugar derivatives in trityl-cyanoalkylidene condensation
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The rate-determining step of trityl-cyanoalkylidene condensation is the interaction between the cyanoalkylidene derivative (CD) and the triphenylmethyl cation.The rate of the reaction follows first-order kinetics with respect to both CD and the catalyst (Tr+) and is independent of the nature and condensation of the trityl ether.Glycosylation rate constants have been determined for CD's most common monosaccharides. - Key words: trityl-cyanoalkylidene condensation; cyanoalkylidene derivatives, mechanism of glycosidation.
- Kitov, P. I.,Tsvetkov, Yu. E.,Backinowsky, L. V.,Kochetkov, N. K.
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p. 1423 - 1428
(2007/10/02)
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- ARYNIC CONDENSATION OF NITRILE ANIONS IN THE PRESENCE OF THE COMPLEX BASE NaNH2-CH3CH2(OCH2CH2)2ONa
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Nitrile anions are easily condensed with aryl halides in the presence of Complex Base NaNH2-CH3CH2(OCH2CH2)2ONa via the intermediate arynes.
- Carre, M. C.,Ezzinadi, A. S.,Zouaoui, M. A.,Geoffroy, P.,Caubere, P.
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p. 3323 - 3330
(2007/10/02)
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- Nucleophilic Substitution Reactions of Alkyl Halides By Using New Polymer-Supported Reagents Containing Hemin
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A new polymer reagent consisting of hemin, divinylbenzene, and 2-methyl-5-vinylpyridine was synthesized by suspension copolymerization.Substitution reactions of primary, secondary, and tertiary alkyl halides with the hemin copolymer combined with cyanide, azide, and thiocyanate ions were given satisfactory yields.This reaction mechanism was revealed to be a SNi type on the basis of stereochemical study.The hemin copolymer was not only a polymer-supported reagent with functional capabilities, but also served to separate the product from the reaction mixture.
- Saito, Kiyoshi,Harada, Kaoru
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p. 2562 - 2566
(2007/10/02)
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- AROMATIC NUCLEOPHILIC SUBSTITUTION ON η6-Cr(CO)3-COMPLEXED HALOGENOARENES: ARYLATION OF SECONDARY CARBANIONS
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The paper deals with the aromatic nucleophilic substitution on η6-Cr(CO)3-complexed fluorobenzene and ortho-, meta-, and para-dichlorobenzenes with stabilized carbanions, both under phase-transfer conditions (PTC) and in DMSO solution.In the case of the η6-Cr(CO)3-complexed ortho-, meta-, and para-dichlorobenzenes only one chlorine atom is replaced by the carbanions.
- Baldoli, Clara,Buttero, Paola Del,Licandro, Emanuela,Maiorana, Stefano
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p. 409 - 414
(2007/10/02)
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- The Synthetic Potential of the Isocyanide-Cyanide Rearrangement
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Excellent chemical and optical yields (>96percent retention) of cyanides are achieved by vapor phase thermolysis or short contact flow thermolysis of isocyanides. trans-2-Butenyl isocyanide rearranges without concomitant allylic isomerization to trans-2-butenyl cyanide.Optically active 1-(formyloxymethyl)-2-phenylethyl cyanide is obtained from optically active L-phenylalanine as a new type of chiral pool synthon.
- Meier, Michael,Ruechardt, Christoph
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- The Isonitrile-Nitrile Rearrangement. A Reaction without a Structure-Reactivity Relationship
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Reproducible rates of isomerisation of aliphatic isonitriles to nitriles in solution can be measured by GLC or IR when free-radical inhibitors are added to suppress a competing radical chain reaction.The reactivities of 19 primary, secondary, tertiary, cyclic, bicyclic, bridgehead, benzyl, substituted-benzyl, α-carbomethoxymethyl, and triphenylmethyl isocyanides in this rearrangement reaction vary by only a factor of 67 in rate or by +/- 2 kcal mol-1 in ΔG(excit.).This is explained by a tight hypervalent three-membered cyclic transition state in agreement with a previous prediction by ab initio calculation.The slower rate of 9-triptycyl isocyanide is proposed to be due to steric hindrance by the three peri hydrogens.Aromatic isocyanides isomerize about 10 times faster independent of polar para substituents and bulky ortho substituents.A hypervalent orthogonal transition state with retention of the aromatic sextet is proposed in contrast to the popular phenonium-type transition states for aryl migration in other 1,2-rearrangements.The reactivity data and the transition-state structures are discussed in context with other cationotropic 1,2-shifts.
- Meier, Michael,Mueller, Barbara,Ruechardt, Christoph
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p. 648 - 652
(2007/10/02)
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- Electrophilic Reactivity of the Triphenylmethyl Carbocation in Aqueous Solutions
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The triphenylmethyl (trityl) carbocation has been generated as a transient intermediate by laser flash photolysis of 1:2 (v/v) acetonitrile:water solutions of trityl acetate and trityl 4-cyanophenyl ether.Identification of the transient as the free carbocation in the ground state was based on its characteristic absorption spectrum and upon conductivity changes.Rate constants have been measured for the reaction of the cation in this solvent with a series of ionic and neutral nucleophiles.The solvent rate constant at 20 deg C is 1.5 x 105 s-1.Azide ions reacts at 4.1 x 109 M-1s-1; the directly measured azide:water ratio is compared to literature values determined by product analysis.Chloride ion reacts at 2 x 106 M-1 s-1; with bromide the equilibrium addition can be observed with k(comb) = 5 x 106 M-1 s-1 and k(ion) for Ph3CBr = 8 x 105 s-1.Rate constants do not adhere to the N+ relationship.This predicts a slope of unity in a plot of log k(Ph3C+) vs.N+, with the better nucleophiles reacting at the 1010 encounter-controlled limit.Azide is the only nucleophile of those studied to approach this.Sulfite and thiolate ions, which are better N+ nucleophiles, react at 2-3 x 108 M-1s-1, while amines react in the 106-107 M-1s-1 range.The plot vs.N+ has a slope of 0.3-0.4.One explanation is that rate constants for the better nucleophiles do level, but this occurs considerably below the 1010 limit.Alternatively, the less than unit slope is real and this more reactive cation, in contrast to more stable analogues, is exhibiting selectivity.
- McClelland, Robert A.,Banait, Narinder,Steenken, Steen
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p. 7023 - 7027
(2007/10/02)
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