Synthesis and Catalytic Properties of Imidazole-Functionalized Poly(propylene imine)Dendrimers

doi:10.5012/bkcs.2002.23.5.647

Cited by 37 publications

(2 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, the influence of poly(aryl ether) branches on the local nanoenvironment surrounding a solvatochromic probe located at the focal point or core of a family of dendrimers was noted 3 more than a decade ago as the absorbance of the probe shifts with increasing dendrimer generation. Aside affecting local polarity, dendrimer repeat units may also provide a platform for cooperativity between branches. − The recognition of their utility has prompted investigations into internal manipulation and functionalization of the dendrimer. ,, …”

Section: Introductionmentioning

confidence: 99%

Incorporation of Functional Guest Molecules into an Internally Functionalizable Dendrimer through Olefin Metathesis

Liang

Fréchet

2005

Macromolecules

View full text Add to dashboard Cite

A poly(aryl ether) dendrimer bearing 22 allyl groups throughout the interior of the molecule has been prepared using a convergent synthetic approach. The internal functionalities of this dendrimer can be used to attach small molecule guests to the interior of the dendrimer using olefin metathesis. A ruthenium-based Grubbs catalyst was used to covalently attach an allylated pyrene and imidazolidinone via cross-metathesis. The extent of coupling was estimated by UV, NMR, and elemental analysis data. The high tolerance of cross-metathesis to a range of functional groups enables the incorporation of a wide range of molecules and provides access to different inner environments in one step from a single source of dendrimer.

show abstract

Section: Introductionmentioning

confidence: 99%

Incorporation of Functional Guest Molecules into an Internally Functionalizable Dendrimer through Olefin Metathesis

Liang

Fréchet

2005

Macromolecules

View full text Add to dashboard Cite

show abstract

“…Motifs bearing triarylmethane (Ar 3 CH) [8–10] and their heterocyclic variants ( Het -Ar) 3 CH [8–12], constitute an integral part of a number of bioactive compounds [13–16]. Due to their valuable properties, they are also well exploited by the chemical industry as dyes and photochromic agents [17–18], protective groups in organic synthesis [19] and as building blocks for dendrimers [20] and nonlinear optical (NLO) properties [21] (Scheme 1). Numerous methods for the construction of triarylmethane frameworks have been developed, with the majority of them bearing simple diaryl or triaryl moieties in their structures [22], and many are performed in multistep processes or require harsh reaction conditions [1–22].…”

Section: Introductionmentioning

confidence: 99%

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts

Abonı́a¹,

Gutiérrez²,

Insuasty³

et al. 2019

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

A series of giant tris(heteroaryl)methanes are easily assembled by one-pot three-component synthesis by simple reflux in ethanol without catalyst or additives. Diversely substituted indoles (Ar1) react with quinoline aldehydes, quinolone aldehydes, chromone aldehydes, and fluorene aldehydes (Ar2CHO) and coumarins (Ar3) in 1:1:1 ratio to form the corresponding tris(heteroaryl)methanes (Ar1Ar2Ar3)CH along with (Ar1Ar1Ar2)CH triads. A series of new 2:1 triads were also synthesized by coupling substituted indoles with Ar2CHO. The coupling reactions could also be carried out in water (at circa 80 °C) but with chemoselectivity favoring (Ar1Ar1Ar2)CH over (Ar1Ar2Ar3)CH. The molecular structure of a representative (Ar1Ar2Ar3)CH triad was confirmed by X-ray analysis. Model tris(heteroaryl/aryl)methylium salts were generated by reaction with DDQ/HPF6 and studied by NMR and by DFT and GIAO-DFT.

show abstract

A Copper(II)‐Catalyzed Aza‐Friedel–Crafts Reaction of N‐(2‐Pyridyl)sulfonyl Aldimines: Synthesis of Unsymmetrical Diaryl Amines and Triaryl Methanes

2006

View full text Add to dashboard Cite

The Lewis acid-catalyzed addition of electron-rich aromatic compounds to aldehydes, ketones and imines, the latter of which is known as the aza-Friedel-Crafts reaction (AFCR), is a synthetically outstanding CÀC bond-forming process that leads to functionalized alcohols and amines in a completely atom-economical way.[1] However, despite its significance, a number of unsolved aspects related to functional-group tolerance, either with regard to the arene nucleophile or the electrophilic substrate, still remain for this transformation. For instance, the mono Friedel-Crafts reaction of carbonyl compounds and imines seems to be restricted to highly electrophilic substrates [2] such as glyoxylates, [3] chloral (trichloroacetaldehyde), [4] pyruvates, [5] trifluoromethyl imines, [6] or a-imino esters. [3c, 7] In contrast, aromatic aldehydes [8] and their imines, [3c, 9] generally evolve according to a double Friedel-Crafts reaction to give symmetrical triaryl methanes due to the intrinsic instability of the intermediate benzylic alcohol (or amine derivative) under the acidic reaction conditions (Scheme 1 a). Triaryl methanes display varied and interesting properties and have received a great deal of attention as leuco dyes, [10] photochromic agents, [11] suitable building blocks for generating dendrimers, [12] and as substrates for theoretical [13] and biological [14] studies. While many methods have been reported for the preparation of symmetrical triaryl methanes, [15] the synthesis of unsymmetrical derivatives is much less developed. [16,17] As part of an ongoing research program on metalcontrolled reactions of appropriately functionalized N-sulfonyl imines, [18] we describe here a broad-scope AFCR protocol that allows the selective preparation of structurally diverse unsymmetrical diaryl amines and triaryl methanes by sequential reaction with two different electron-rich aromatic compounds (Scheme 1 b).First, to study the effect of the sulfonyl substitution in AFCR, a set of sulfonyl imines, 1 a-e, of varied electronic and coordination nature were readily prepared in good chemical yields (87-94 %) by direct condensation of benzaldehyde with the corresponding sulfonamide (Scheme 2). [19] We chose the electron-rich N-methylindole [20] as model aromatic nucleophile for the AFCR of compounds 1, and Cu(OTf) or Cu(OTf) 2 as catalytic Lewis acids [21] (10 mol %). Scheme 2. Synthesis of N-sulfonyl imines 1 a-e. M.S. = molecular sieves.

show abstract

Synthesis and Catalytic Properties of Imidazole-Functionalized Poly(propylene imine)Dendrimers

Cited by 37 publications

References 26 publications

Incorporation of Functional Guest Molecules into an Internally Functionalizable Dendrimer through Olefin Metathesis

Incorporation of Functional Guest Molecules into an Internally Functionalizable Dendrimer through Olefin Metathesis

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts

A Copper(II)‐Catalyzed Aza‐Friedel–Crafts Reaction of N‐(2‐Pyridyl)sulfonyl Aldimines: Synthesis of Unsymmetrical Diaryl Amines and Triaryl Methanes

Contact Info

Product

Resources

About