Pd-catalyzed reactions on pyridinium N-heteroarylaminides. Step-by-step synthesis of 3,5-unsymmetrically disubstituted 2-aminopyridines (original) (raw)
Related papers
Tetrahedron, 2008
An extensive study of SuzukieMiyaura cross-coupling processes on N-pyridinium bromoazinyl aminides has been performed. Mono-and disubstitution on 5-and 3,5-bromo derivatives produced the corresponding aryl derivatives. In the disubstituted compounds regioselective substitution at the 3-position occurred, vicinal to the aminide nitrogen, and this was more evident in pyrazine derivatives. The commonly used strategy involving N-alkylation and reduction of the NeN bond gave rise to a series of 2-alkylamino-3,5-disubstituted-pyrazines.
New approaches to the synthesis of pyridinium N-heteroarylaminides
Tetrahedron, 2008
Different substituted pyridinium N-heteroarylaminides have been prepared in one step from N-aminopyridinium iodide and the corresponding heteroaryl halide by two alternative routes. The use of Pd catalysis allowed the easy preparation of products from the less reactive haloheterocycles. The use of water as a solvent in conjunction with microwave heating dramatically diminishes the reaction time without having an adverse effect on reaction yields.
Convenient Access to New 4-Substituted Aminopyrido [2,3-d]pyrimidine derivatives
Tetrahedron Letters, 2015
We describe in this Letter, a novel series of pyrido[2,3-d]pyrimidines 6-11 derived from 3-cyano-2aminopyridines 4a-f via formamidine formation 5a-f followed by selective nucleophilic addition, with different primary amines, under solvent-free conditions. The structures of the newly synthesized compounds are confirmed by spectral analysis. This new approach includes some important aspects such as mild reaction conditions, high yields, and environmentally friendly process. The operational simplicity of this synthetic route will offer an attractive alternative to the conventional methods.
Molecules, 2017
The present study describes palladium-catalyzed one pot Suzuki cross-coupling reaction to synthesize a series of novel pyridine derivatives 2a-2i, 4a-4i. In brief, Suzuki cross-coupling reaction of 5-bromo-2-methylpyridin-3-amine (1) directly or via N-[5-bromo-2-methylpyridine-3-yl]acetamide (3) with several arylboronic acids produced these novel pyridine derivatives in moderate to good yield. Density functional theory (DFT) studies were carried out for the pyridine derivatives 2a-2i and 4a-4i by using B3LYP/6-31G(d,p) basis with the help of GAUSSIAN 09 suite programme. The frontier molecular orbitals analysis, reactivity indices, molecular electrostatic potential and dipole measurements with the help of DFT methods, described the possible reaction pathways and potential candidates as chiral dopants for liquid crystals. The anti-thrombolytic, biofilm inhibition and haemolytic activities of pyridine derivatives were also investigated. In particular, the compound 4b exhibited the highest percentage lysis value (41.32%) against clot formation in human blood among all newly synthesized compounds. In addition, the compound 4f was found to be the most potent against Escherichia coli with an inhibition value of 91.95%. The rest of the pyridine derivatives displayed moderate biological activities.
Development of More Potent 4-Dimethylaminopyridine Analogues
Organic Letters, 2007
The syntheses of bicyclic diaminopyridines 3 and 4 and tricyclic triaminopyridines 5 and 6, two novel series of nucleophilic catalysts, are described. Arguments are made for predicting the superiority of these catalysts over DMAP and even 2, the best esterification catalyst reported to date. The efficiencies of DMAP, PPY, and 2−6 in catalyzing the esterification of tertiary alcohols were compared. As predicted, 5 and 6 were about 6-fold more effective than DMAP and slightly better than 2. Catalytic amounts of 4-dimethylaminopyridine (DMAP) or 4-pyrrolidinopyridine (PPY) cause enormous rate accelerations in the acylation reactions of amines and, particularly, alcohols with carboxylic acid halides and anhydrides. 1 Such reactivity enhancements are not only confined to acylations but also occur in carbamylation, sulfonylation, phosphorylation, and silylation reactions of alcohols and amines. 2-7 DMAP and PPY are therefore the nucleophilic catalysts of choice for such reactions, especially when an alcohol or amine is less reactive, and their use in syntheses has been the subject of several reviews. 8,9 The increase in reactivity is also occasionally accompanied by improvements in regioand stereoselectivity as well. 8 Furthermore, in recent years, chiral variants of DMAP have been developed for the successful kinetic resolution of alcohols and amines. 10-15 The development of the even more potent DMAP/PPY analogues 1 and 2 was reported by Steglich et al. 16 Extending his line of reasoning, we hypothesized and predicted that the two novel series of catalysts, bicyclic diaminopyridines 3 and 4, and tricyclic triaminopyridines 5 and 6, should be even more effective. In this paper, we report the development of general protocols for the synthesis of these novel Nsubstituted bicyclic and tricyclic pyridines as well as the
A Convenient Route for the Synthesis of 4-Aryl- and 4-Aminopyrimidines
Monatshefte f�r Chemie/Chemical Monthly, 2004
A series of ureidopropenenitriles were synthesised by Knoevenagel condensation of ArCOCH 2 CN and HC(OEt) 3 in presence of ureas in a one pot reaction. These ureidopropenenitriles were cyclised to 4-aryl-5-cyano-3-substituted pyrimidines (in acid) or to 4-amino-5-benzoylpyrimidines (in base) in 60-70% yields. The amine pyrimidine derivatives were further converted to substituted uracils by hydrolysis with isopentyl nitrite in DMF. Alkylation of uracils furnished 1,3-dimethyluracil derivatives with DMS in alkali. All new compounds were characterised by spectral and analytical methods.