21901-40-6Relevant articles and documents
Molecular and crystal structures, vibrational studies and quantum chemical calculations of 3 and 5-nitroderivatives of 2-amino-4-methylpyridine
Bryndal,Kucharska,Sasiadek,Wandas,Lis,Lorenc,Hanuza
, p. 952 - 962 (2012)
The crystal structures of 2-amino-4-methyl-3-nitropyridine (I), 2-amino-4-methyl-3,5-dinitropyridine (II) and 2-amino-4-methyl-5-nitropyridine (III) have been determined. The compounds crystallize in the monoclinic P2 1/n, triclinic P-1 and monoclinic C2/c space groups, respectively. These structures are stabilized by a combination of N-H···N and N-H···O hydrogen bonds and exhibit layered arrangement with a dimeric N-H···N motif in which the molecular units are related by inversion centre. The molecular structures of the studied compounds have been determined using the DFT B3LYP/6-311G(2d,2p) approach and compared to those derived from X-ray studies. The IR and Raman wavenumbers have been calculated from the optimized geometry of monomers and dimers formed in the unit cell and compared to the experimental values obtained from the spectra.
Transition-metal-free access to 2-aminopyridine derivatives from 2-fluoropyridine and acetamidine hydrochloride
Li, Yibiao,Huang, Shuo,Liao, Chunshu,Shao, Yan,Chen, Lu
supporting information, p. 7564 - 7567 (2018/11/02)
Under catalyst-free conditions, an efficient method for the synthesis of 2-aminopyridine derivatives through the nucleophilic substitution and hydrolysis of 2-fluoropyridine and acetamidine hydrochloride has been developed. This amination uses inexpensive acetamidine hydrochloride as the ammonia source and has the advantages of a high yield, high chemoselectivity and wide substrate adaptability. The results suggest that other N-heterocycles containing fluorine substituents can also complete the reaction via these reaction conditions and yield the target products.
Theoretical and experimental NMR data of 3,5-dinitro-2-(2-phenylhydrazinyl) pyridine and of its 4- and 6-methyl derivatives
Wandas,Talik
, p. 15 - 27 (2013/07/05)
3,5-Dinitro-2-(2-phenylhydrazinyl)pyridine and its methyl derivatives: 4-methyl-3,5-dinitro-2-(2-phenylhydrazinyl)pyridine and 6-methyl-3,5-dinitro-2- (2-phenylhydrazinyl)pyridine were synthesized and characterized by 1H NMR and 13C NMR. Calculations were also performed where the above molecules were optimized using the methods of density functional theory (DFT) with 6-31G(d,p) and 6-311G(d,p) basis sets. For all molecules studied, the lowest energy was obtained using the 6-311G(d,p) basis set. The GIAO/DFT (Gauge Invariant Atomic Orbitals/Density Functional Theory) calculations on the 6-311G and 6-311++G and 6-311G* basis sets were carried out to determine proton and carbon chemical shifts and to find they were close to the experimental values. It has been also found that intramolecular hydrogen bonding exists between hydrogen atom (in 2-NH group) and oxygen atom (pyridine-3-NO2). Moreover, resonances between pyridine ring and electron withdrawing 3-nitro group as well between that ring and the lone electron pair of NH group favor a co-planarity of the structure; this means a chelate ring created by above-mentioned intramolecular hydrogen bond is almost co-planar with pyridine ring.
