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Covalent ligand-target interactions offer significant pharmacological advantages. However, off-target reactivity of the reactive groups, which usually have electrophilic properties, must be minimized, and the selectivity of irreversible inhibitors is a crucial requirement. We therefore performed a systematic study to determine the selectivity of several electrophilic groups that can be used as building blocks for covalently binding ligands. Six reactive groups with modulated electrophilicity were combined with 11 nonreactive moieties, resulting in a small combinatorial library of 72 fragment-like compounds. These compounds were screened against a group of 11 enzyme targets to assess their selectivity and their potential for promiscuous binding to proteins. The assay results showed a considerably lower degree of promiscuity than initially expected, even for those members of the screening collection that contain supposedly highly reactive electrophiles.

An efficient, simple, and practical method has been developed for the deprotection of prenyl, geranyl, and phytyl ethers and esters of aromatic and aliphatic compounds using borontrifluoride-etherate (BF3· OEt2) at room temperature in good to excellent yields for the first time. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file. Copyright Taylor & Francis Group, LLC.

An efficient N-selective alkylation of primary aromatic amines in molten quaternary ammonium salts, as the solvent, under relatively mild and base-free conditions is presented. On the basis of the Kamlet-Taft parameters and the nucleophilicity of the IL (ionic liquid) anions, the influence of the ionic liquid was evaluated. This protocol was validated on a larger multigram scale and with the syntheses of bioactive heterocycles (e.g., 1,4-benzothiazine and quinoxalines) and new efficient MALDI matrixes. Copyright

2-Carbomethoxy-3-hydroxyquinoxaline-di-N-oxide was identified as an efficient novel ligand for the copper-catalyzed coupling reactions of aryl iodides, bromides, and chlorides with aliphatic amines and N-containing heterocycles under mild conditions. The catalytic system showed great functional-group tolerance and excellent chemoselectivity. 7copy; 2012 Elsevier Ltd. All rights reserved.

A new synthesis of phenanthridine derivatives having three-point diversity has been developed based on the sequential application of three-atom economic processes viz. aza-Claisen rearrangement, ring-closing enyne metathesis and Diels-Alder reaction as key steps. An unexpected isomerisation was observed during aza-Claisen rearrangement of N-allylanilines which may open up new opportunities in heterocyclic synthesis.

(Figure presented) A highly efficient and regioselective allylation reaction of amines and active methylene compounds directly using allylic alcohols under mild conditions catalyzed by the novel cubane-type sulfido [(CpMo)3(μ3-S)4Pd(η3-allyl)] [PF6]2 clusters has been developed. A variety of allylic alcohols and nucleophiles including amines and active methylene compounds are investigated, and in the case of allylic alcohols bearing substituents at either the α- or γ-position only linear products are obtained.

N-Alkylation of amines suffers from competing over alkylations. At the same time, use of strong base and other harsh conditions greatly limits providing a practical, generalized and selective procedure. Activated silica gel has been found to promote N-alkylations of amines. Here, we studied N-alkylation of amines with various types of alkyl halides, which finally constitute practical, highly selective and eco-friendly conditions for mono- or bis-alkylated amines at ambient temperature with recyclability of silica.

(Equation presented) A mild intermolecular copper-mediated amination of aryl iodides has been developed. The reaction takes place at room temperature or heating at 90°C and tolerates halogens attached to the aromatic ring. Its synthetic applications include a synthetic protocol for unsymmetrical N,N′-dialkylated phenylenediamines and both a stepwise and a general synthetic method for N-aryl secondary amines via Ns-anilides (readily obtained by reaction of the Ns-amide).

Using a polymer-bound selenenyl bromide resin, o-allyl and o-prenyl anilines were cycloaded to afford a series of solid-supported indoline and indole scaffolds. These scaffolds were then functionalized and cleaved via four distinct methods, namely traceless reduction, radical cyclization, radical rearrangement, and oxidative elimination, to afford 2-methyl indolines, polycyclic indolines, 2-methyl indoles, and 2-propenyl indolines, respectively. A number of small combinatorial libraries of compounds reminiscent of certain designed ligands of biological interest were constructed demonstrating the potential utility of the developed methodology to chemical biology studies and the drug discovery process.

At atmospheric pressure and at 130-160°C, primary aromatic amines (p-XC6H4NH2, X = H, Cl, NO2) are mono-N-alkylated in a single step, with symmetrical and asymmetrical dialkyl carbonates [ROCOOR′, R = Me, R′ = MeO(CH2)2O(CH2)2; R = R′ = Et; R = R′ = benzyl; R = R′ = allyl; R = Et, R′ = MeO(CH2)2O(CH2)2], in the presence of a commercially available NaY faujasite. No solvents are required. Mono-N-alkyl anilines are obtained with a very high selectivity (90-97%), in good to excellent yields (68-94%), on a preparative scale. In the presence of triglyme as a solvent, the mono-N-alkyl selectivity is independent of concentration and polarity factors. The reaction probably takes place within the polar zeolite cavities, and through the combined effect of the dual acid-base properties of the catalyst.

N-Allylation of anilines using allylic alcohols directly to give monoallylic anilines selectively in high yields has been realized by employing palladium acetate-triphenylphosphine as the catalyst. Palladium-catalyzed one-pot cyclization of 2-aminophenols with 2-butene-1,4-diol leads to 3,4-dihydro-2-vinyl-2H-1,4-benzoxazines. (C) 2000 Elsevier Science Ltd.

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A quick and efficient approach for mono N-allylamines has been developed by the reaction of allyl zinc reagent with alkyl and aryl azides in DMF. - Keywords: azides; zinc; DMF; allylamine

The direct activation of C-O bonds in allyl alcohols by palladium complexes has been accelerated by carrying out the reactions in the presence of titanium(IV) isopropoxide and molecular sieves (4A). N-Allylation of anilines to give mono- and diallylanilines directly using allyl alcohols has been realized by employing palladium catalysts.

The nucleophilic substitution reactions of aromatic halides having electron-attracting groups on ortho or para position with various primary and secondary amines were accelerated by high pressure to give the corresponding N-substituted anilines in high yields.The bulkiness of amines affects its reactivity to lower the yields of the products.Although the secondary amines are usually less reactive than primary amines, cyclic secondary amines such as morpholine, piperidine, and pyrrolidine were found very reactive. 1,4-Diazabicyclooctane and quinuclidine gave N-quarternary ammonium halides in high yields in contrast to the low reactivity of acyclic tertiary amines.Dichloro- and trichloro-nitrobenzenes also react with diethylamine, pyrrolidine, and morpholine to give mono-, di-, and trisubstitution products depending upon the amount of amine and the position of nitro group in these chlorides.

Allylsilanes were treated with benzenetellurinyl trifluoracetate below room temperature followed by amines at 65 deg.C in 1,2-dichloroethane in the presence of boron trifluoride etherate, readily giving allylamines.

Zeolite K-Y is effective as a promoter in the N-alkylation of aniline derivatives in comparison with γ-alumina.