7500-76-7Relevant academic research and scientific papers
Niobium Pentachloride Mediated (Hetero)aromatic Aldehyde Friedel-Crafts Hydroxyalkylation with Arenes: An Efficient Strategy to Synthesize Triarylmethanes
Baviera, Giovanni S.,Donate, Paulo M.,Matias, Alexandre A.,Previdi, Daniel,Rodrigues, Shirley M. M.
, p. 4498 - 4506 (2019/11/21)
Niobium pentachloride is an efficient and useful Lewis acid to conduct Friedel-Crafts hydroxyalkylation between arenes and (hetero)aromatic aldehydes, to generate triarylmethanes. This practical methodology offers several advantages, such as short reaction time, mild experimental conditions, and excellent yields.
Lewis acid-mediated mono- and bis-addition of C-nucleophiles to 1,3-dioxolan-4-ones
Shcherbinin, Vitaly A.,Konshin, Valery V.
, p. 3005 - 3009 (2018/07/06)
The reactions of 1,3-dioxolan-4-ones, readily available from α-hydroxy acids and aldehydes, with C-nucleophiles are described. Two possible reaction pathways resulting in O-substituted acids and tri-(hetero)arylmethanes are shown.
Solventless triarylmethane synthesis via hydroxyalkylation of anisole with benzaldehyde by modified heteropoly acid on mesocellular foam silica (MCF)
Bhadra, Kalpesh H.,Yadav, Ganapati D.
, p. 150 - 158 (2018/06/18)
Triarylmethane (TRAM) compounds have wide applications such as leuco dyes for sensing tumors and other biological activities. Hydroxyalkylation of arenes with benzaldehyde results in formation of triarylmethane compounds. In the present study, 20 (wt.%) Cs2.5H0.5PW12O40 (Cs-DTP) supported on mesocellular foam (MCF) silica was prepared, characterized and tested for its activity in hydroxyalkylation reaction of anisole with benzaldehyde. Its activity was compared with commercial catalysts like Amberlyst-15, montmorillonite clay K-10, H3PW12O40 and unsupported Cs2.5H0.5PW12O40.The prepared catalyst showed the best activity compared to others with advantage of separation of catalyst and reusability. Reaction parameters were studied in detail and kinetic study was carried out for the said reaction. 20 (wt. %) Cs-DTP/MCF was found to be the best, robust and reusable catalyst. Reaction mechanism and kinetics were also studied. The results are new.
Synthesis of Tetraarylmethanes by the Triflic Acid-Promoted Formal Cross-Dehydrogenative Coupling of Triarylmethanes with Arenes
Nambo, Masakazu,Yim, Jacky C.-H.,Fowler, Kevin G.,Crudden, Cathleen M.
supporting information, p. 2936 - 2940 (2017/10/09)
The formal cross-dehydrogenative coupling of triarylmethanes with arenes promoted by triflic acid and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone is described. This method provides a variety of tetraarylmethane derivatives in good to excellent yields from triarylmethanes that can be readily prepared by our previous methods. Control experiments suggest a possible catalytic cycle involving the generation of a trityl cation intermediate followed by nucleophilic addition of the arene.
Hydride Reduction by a Sodium Hydride-Iodide Composite
Too, Pei Chui,Chan, Guo Hao,Tnay, Ya Lin,Hirao, Hajime,Chiba, Shunsuke
supporting information, p. 3719 - 3723 (2016/03/26)
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.
Triggering the approach of an arene or heteroarene towards an aldehyde via Lewis acid-aldehyde communication
Pratihar, Sanjay
, p. 2854 - 2865 (2016/03/12)
The present work reports a combined experimental/computational study of the Lewis acid promoted hydroxyalkylation reaction involving aldehyde and arene/heteroarene and reveals a mechanism in which the rate determining aldehyde to alcohol formation via a four-member cyclic transition state (TS) involves a transfer of hydrogen from arene/heteroarene C-H to aldehyde oxygen with the breaking of the C-H bond and formation of C-C and O-H bonds. The effect of different Sn(iv) derivatives on the hydroxyalkylation reaction from different in situ NMR and computational studies reveals that although the exergonic formation of the intermediate and its gained electrophilicity at the carbonyl carbon drive the reaction in SnCl4 compared to other Sn(iv) derivatives, the overall reaction is low yielding because of its stable intermediate. With respect to different aldehydes, LA promoted hydroxylation was found to be more feasible for an electron withdrawing aldehyde compared to electron rich aldehyde because of lower stability, enhanced electrophilicity gained at the aldehyde center, and a lower activation barrier between its intermediate and TS in the former as compared to the latter. The relative stability of the LA-aldehyde adduct decreases in the order SnCl4 > AlCl3 > InCl3 > BF3 > ZnCl2 > TiCl4 > SiCl4, while the activation barrier (ΔG#) between intermediate and transition states increases in the order AlCl3 4 3 3 4 2 4. On the other hand, the activation barriers in the case of different arenes/heteroarenes are in the order of indole 3, InCl3 and SnCl4 because they have negative free energy of formation (ΔG) for alcohol to the corresponding diaryl methyl carbocation.
Friedel-crafts alkylation of arenes catalyzed by ion-exchange resin nanoparticles: An expedient synthesis of triarylmethanes
Reddy, B. V. Subba,Venkateswarlu,Sridevi,Aldeyab, Salem S.,Vinu, Ajayan
, p. 6826 - 6832 (2015/11/24)
Friedel-Crafts alkylation of electron-rich arenes with aldehydes has been achieved in the presence of an active and selective Amberlyst-15 catalyst at the reaction temperature of 60 ° C in solvent-free conditions. The catalyst exhibitsby a very high activity and offers the corresponding triarylmethanes in excellent yields with a high selectivity. The use of highly reactive and selective Amberlyist-15 makes this procedure simple, convenient, cost-effective, practical and environmentally friendly. This method provides an easy access to triarylmethanes in a single step using a readily available acidic ionic resin, which is a stable and easy to separate from the reaction mixture by a simple filtration technique.
The cooperative effect of Lewis pairs in the Friedel-Crafts hydroxyalkylation reaction: A simple and effective route for the synthesis of (±)-carbinoxamine
Harikrishnan, Adhikesavan,Sanjeevi, Jayakumar,Ramanathan, Chinnasamy Ramaraj
, p. 3633 - 3647 (2015/03/30)
An efficient C-C bond formation strategy between aromatic/heteroaromatic π-nucleophiles and Lewis acid activated aldehydes is described. This aromatic electrophilic substitution reaction of arenes or heteroarenes is facilitated by Lewis acid AlBr3. Aromatic rings with electron donating substituents are excellent nucleophilic counterparts in this reaction, generating carbinols in excellent yields (61-94%). The formation of triarylmethanes is also witnessed in the case of certain reactive aldehydes and aromatic π-nucleophiles through reactive carbocation formation. The formation of triarylmethane is reduced to a greater extent via retardation of the second π-nucleophile addition through a Lewis base, for example, pyridine, coordination with an aluminium alkoxide intermediate. Various aliphatic aldehydes also underwent Friedel-Crafts type hydroxyalkylation and generated the expected carbinols in moderate yields (41-53%) in the presence of AlBr3. This protocol has been successfully applied to the synthesize of the (±)-carbinoxamine, a therapeutically important histamine H1 antagonist, in a one-pot manner.
Di- and triarylmethylium ions as probes for the ambident reactivities of carbanions derived from 5-benzylated Meldrum's acid
Chen, Xi,Tan, Yue,Berionni, Guillaume,Ofial, Armin R.,Mayr, Herbert
, p. 11069 - 11077 (2014/10/15)
The kinetics of the reactions of carbocations with carbanions 1 derived from 5-benzyl-substituted Meldrum's acids 1-H (Meldrum's acid=2,2-dimethyl-1,3- dioxane-4,6-dione) were investigated by UV/Vis spectroscopic methods. Benzhydryl cations Ar2CH+ added exclusively to C-5 of the Meldrum's acid moiety. As the second-order rate constants (kC) of these reactions in DMSO followed the linear free-energy relationship lg k=s N(N+E), the nucleophile-specific reactivity parameters N and s N for the carbanions 1 could be determined. In contrast, trityl cations Ar3C+ reacted differently. While tritylium ions of low electrophilicity (E-2) reacted with 1 through rate-determining β-hydride abstraction, more Lewis acidic tritylium ions initially reacted at the carbonyl oxygen of 1 to form trityl enolates, which subsequently reionized and eventually yielded triarylmethanes and 5-benzylidene Meldrum's acids by hydride transfer.
Iron-catalyzed arylation of aromatic ketones and aldehydes mediated by organosilanes
Savela, Risto,Majewski, Marcin,Leino, Reko
, p. 4137 - 4147 (2014/07/08)
A simple and efficient iron-catalyzed method for arylation of aromatic carbonyl compounds is reported. The use of 4-% FeCl3 or Fe(acac) 3 as the catalyst, in combination with a slight excess of chlorotrimethylsilane and triethylsilane, chlorination of benzylic ketones and aldehydes with subsequent Friedel-Crafts alkylation of arenes is achieved. Although the method is limited by the general constraints associated with Friedel-Crafts alkylation reactions, robust applications for the synthesis of pharmaceutical intermediates and so on can be envisioned. A robust one-pot, iron-catalyzed chlorination Friedel-Crafts alkylation reaction of benzylic carbonyl compounds, mediated by chlorotrimethylsilane and triethylsilane, has been developed to yield substituted diaryl and triaryl building blocks. Copyright
