1H and13C spectral assignment ofo-chloroformyl substituted 1,4-dihydropyridine derivatives (original) (raw)
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NMR study of 1,4-dihydropyridine derivatives endowed with long alkyl and functionalized chains
Journal of the Brazilian Chemical Society, 2011
Neste trabalho, realizou-se um estudo por ressonância magnética nuclear de 1 H, 13 C e 15 N de derivados de 1,4-dihidropiridinas que contêm, nos grupos ésteres das posições C-3 e C-5, longas cadeias alquílicas ou funcionalizadas. Atribuíram-se inequivocamente os sinais dos espectros utilizando experimentos 1D e 2D (DEPT, nOe, HMQC, HMBC, COSY).
Studies of Dihydropyridines by X-Ray Diffraction and Solid State 13C NMR
Zeitschrift für Naturforschung B, 2007
Fourteen dimethyl 4-aryl-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylates (DHPs) were evaluated by means of single crystal X-ray diffraction in order to investigate the effects of the structure in the crystals on the solid state 13C NMR chemical shifts. These include the analysis of three DHPs containing two molecules per asymmetric unit. The chiral rotamer unit generated by the s-cis/s-trans orientation of the carbonyl groups, as well as by rotation of the 4-phenyl ring out of the bisecting plane containing the N1, C4, C7 atoms, resulted in a significant magnetic non-equivalence for the C2-CH3/C6-CH3 and the COOCH3 pairs of signals. The solid state 13C NMR data reveal that the substitution pattern of the phenyl ring has a marked effect on the extent to which the signals of the carbonyl carbon atoms and those of C-2/C-6 peaks are split.
Spectroscopy Letters, 1993
C-13 and H-1 NMR spectra of some 1-(4'-dimethylaminobenzylideneamino)pyridiniurn perchlorates show that the angle of twist of the pyridine ring in unsubstituted, 1, and 2-alkyl substituted compounds 2-5 is comparable. However, it is considerably increased in 2.6-dialkyl derivatives. As seen from the spectral data, pyridine and phenyl rings in 2,6-diphenyl derivative 15 are not coplanar. The effect of 4-alkyl substituent is of hyperconjugative chacter. In general, the amount of the positive charge at C-4 in 2 , 6-dialkyl substituted salts is higher as compared to 2-monosubstituted compounds.
Intramolecular C-H···O Hydrogen Bonding in 1,4-Dihydropyridine Derivatives
Molecules, 2011
The diastereotopy of the methylene protons at positions 2 and 6 in 1,4dihydropiridine derivatives with various substituents has been investigated. NMR spectroscopy and quantum chemistry calculations show that the CH•••O intramolecular hydrogen bond is one of the factors amplifying the chemical shift differences in the 1 H-NMR spectra.
Synthesis and structural conformation of N-substituted 1,4-dihyropyridine derivatives
Crystal Research and Technology, 2006
N-(Phenyl)-3,5-dicarbethoxy-2,6-dimethyl-4-(phenyl)-1,4-dihydropyridine (A) and N-(4-methoxy phenyl)-3,5 dicarbethoxy-2,6 dimethyl-4-(3-nitro phenyl)-1,4-dihydropyridine (B) has been synthesized as per scheme and characterized by the X-ray diffraction method. The compound A crystallizes in monoclinic space group P2 1 /c with cell parameters a = 9.2770(11)Å, b = 8.6410(5)Å, c = 27.601(3)Å, β = 97.724(3)°, Z = 4. The compound B crystallizes in monoclinic space group P2 1 /c with cell parameters a = 11.229(6), b = 12.746(7)Å, c =17.606(6)Å, β = 104.531(3)°, Z = 4. The structures exhibit both intra and intermolecular hydrogen bonds. Dihydropyridine ring of both the compounds adopt a flat boat conformation.
International Letters of Chemistry, Physics and Astronomy, 2014
A series of 2-Amino-4-isopropyl-6-methoxy-N-phenylpyrimidine-5-carboxamide compounds have been synthesized from various substituted dithioacetal and guanidine. The purities of these compounds were checked by their physical constants, UV, IR, NMR and MASS spectral data. The IR and 1HNMR spectral data of these compounds have been correlated with Hammett sigma constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effects of substituents on the spectral group frequencies have been discussed.
Carboxamides of Dihydropyridin‐2(1H)‐ones
ChemInform, 2003
3-Carboxamides and 3-carboxanilides of 6-alkyl and 6-aryldihydropyridin-2(1H)-ones have been prepared via different reaction pathways. All synthesized amides show hydrogen bonds in their NMR spectra. The 4-hydroxy compounds were obtained as a mixture of tautomers. Their configurations were elucidated by NMR experiments.