scholarly journals IR and NMR Spectral Studies of Some 4-(6-methoxy-2-naphthyl)-5,6-dihydro-6-(Substituted Phenyl)-4H-1,3-Oxazine-2-Amines: Assessment of Substituent

Author(s):  
Ganesamoorthy Thirunarayanan

A series containing thirteen title compounds were synthesized and recorded IR and NMR spectra. The infrared νNH, C=N(cm-1)stretches, 1H NMR δNH, 13C NMR δC=N(ppm) chemical shifts of synthesized oxazine amines were assigned and correlated with Hammett substituent constants, F and R parameters. From the results of statistical analyses, the effect of substituents on the above spectral frequencies can be discussed.

Author(s):  
G. Thirunarayanan ◽  
I. Muthuvel ◽  
V. Sathiyendiran

A series of eleven substituted dipyrido[3,2-a; 2′,3′-c]phenazine derivatives have been synthesized and examined their purities by literature method. The infrared and 13C NMR spectral data of prepared phenazines were correlated with Hammett substituent constants, F and R parameters using single and multi-regression analysis. From the results of statistical analysis, the effect of substituents on the infrared frequencies (ν, cm-1) and 13C nmr chemical shifts(δ, ppm) has been studied.


1975 ◽  
Vol 30 (9-10) ◽  
pp. 788-793 ◽  
Author(s):  
Ludger Ernst

During a reinvestigation of the 13C NMR spectra of 1-fluoronaphthalene (1) and of 2-fluoronaphthalene (2) at 20 and 25.16 MHz, uncertainties that existed in the literature about signal assignments for 1 could be cleared. In the spectral analyses for 2 given so far, five out of ten signals were incorrectly assigned. The corrected assignment is supported by extensive 13C{1H} double resonance experiments, by recording of proton-coupled 13C and 13C{19F} spectra and by off-resonance 13C{1H} noise-decoupling. The results show a strong + M-effect of the fluorine substituents on 13C chemical shifts similar to the effects of OH and OCH3 groups. 1H NMR spectra of 1 and 2 could be partially assigned by decoupling of the 19F resonances and by iterative analysis.


2006 ◽  
Vol 61 (10-11) ◽  
pp. 600-606
Author(s):  
Savitha M. Basappa ◽  
Basavalinganadoddy Thimme Gowda

Twenty six N-(2/3/4-substituted phenyl)-2,4-disubstituted benzenesulphonamides of the general formulae 2,4-(CH3)2C6H3SO2NH(i-XC6H4), 2-CH3-4-ClC6H3SO2NH(i-XC6H4) and 2,4- Cl2C6H3SO2NH(i-XC6H4), where i-X = H, 2-CH3, 3-CH3, 4-CH3, 2-Cl, 3-Cl, 4-Cl, 4-F or 4-Br, have been prepared, characterized and their infrared spectra in the solid state and 1H and 13C NMR spectra in solution studied. The infrared N-H stretching vibrational frequencies vary in the range 3298 - 3233 cm−1. Asymmetric and symmetric SO stretching vibrations appear in the ranges 1373 - 1311 cm−1 and 1177 - 1140 cm−1, respectively, while C-S, S-N and C-N stretching absorptions vary in the ranges 840 - 812 cm−1, 972 - 908 cm−1 and 1295 - 1209 cm−1, respectively. The various 1H and 13C NMR chemical shifts are assigned to the protons and carbon atoms of the two benzene rings in line with those for similar compounds. The incremental shifts due to the groups in the parent compounds have been computed by comparing the chemical shifts of the protons or carbon atoms in these compounds with those of benzene or aniline, respectively. The computed incremental shifts and other data were used to calculate the 1H and 13C NMR chemical shifts of the substituted compounds in three different ways. The calculated chemical shifts by the three methods compared well with each other and with the observed chemical shifts. It is observed that there are no particular trends in the variation of either the infrared absorption frequencies or the chemical shifts with the nature or site of substitution.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Namratha Bhandari ◽  
Santosh L. Gaonkar

The paper describes a convenient method for the preparation of 4-substituted phenyl-5-[1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-yl]-2H-1,2,4-triazole-3-thiones. The structures of the synthesized compounds are established by the results of LCMS, 1H NMR, 13C NMR, and IR and elemental analyses. The mercaptotriazoles are indicated to be in thione form by 1H NMR spectra. All the synthesized compounds have been screened for antibacterial and antifungal activities. Compounds 12d and 12h exhibit encouraging results, while the remaining compounds show moderate activities. On the basis of spectral studies, formation of 2-amino-1,3,4-thiadiazoles from the isobenzofuran acyl thiosemicarbazides 11(a–h) is ruled out.


1983 ◽  
Vol 48 (3) ◽  
pp. 877-888 ◽  
Author(s):  
Eva Petráková ◽  
Jan Schraml

All methyl O-benzoyl-β-D-xylopyranosides have been prepared and their 1H and 13C NMR spectra measured in deuteriochloroform solutions. The 1H NMR spectra were analysed to the first order and assigned with the aid of homonuclear decoupling. The 13C chemical shifts were assigned through heteronuclear selective decouling experiments. Some of the 13C chemical shifts observed in di- and tri-O-benzoyl derivatives differ considerably from those calculated according to the direct additivity rule from the shifts in the mono derivatives. It is shown that the nonadditivity is due to a conformational heterogeneity of the series of investigated compounds dissolved in deuteriochloroform. The heterogeneity is evidenced by the vicinal 1H-1H coupling constants and by 13 chemical shifts of C(1) methoxyl carbon atoms.


Author(s):  
Ganesamoorthy Thirunarayanan ◽  
I. Muthuvel ◽  
V. Sathiyendiran

A series of 6-substituted quanoxaline derivatives have been synthesized and examined their purities by literature method. The infrared and 13C NMR spectral data of these quinoxalines were correlated with Hammett substituent constants, F and R parameters using single and multi-regression analysis. From the results of statistical analysis, the effect of substituents on the spectral frequencies has been studied.


2006 ◽  
Vol 61 (10-11) ◽  
pp. 595-599
Author(s):  
Basavalinganadoddy Thimme Gowda ◽  
Shilpa Lakshmipathy ◽  
Jayalakshmi K. Lakshmipathy

Nineteen N-(2/3/4-methyl/halo/nitro-phenyl)-acetamides and substituted acetamides, 2/3/4- YC6H4NH-CO-CH3−iXi (Y = CH3, F, Cl, Br or NO2; X = Cl or CH3 and i = 0, 1, 2 or 3), have been prepared, characterized, and their 1H and 13C NMR spectra in solution measured and correlated. 1H and 13C NMR chemical shifts were assigned to the protons and carbon atoms, respectively, in line with those for similar compounds. Since the chemical shifts are dependent on the electron density around the nucleus or associated with the atom to which it is bound, the incremental shifts of the aromatic protons or carbon atoms due to -NH-CO-CH3−iXi and -CO-CH3−iXi (X = Cl or CH3 and i = 0, 1, 2, 3) in all the N-phenyl-substituted acetamides, C6H5NH-CO-CH3−iXi, are calculated by comparing the proton or carbon chemical shifts of these compounds with those of benzene or aniline. The incremental shifts due to the groups in the parent compounds have also been computed by comparing the chemical shifts of the protons or carbon atoms in these compounds with those of benzene or aniline, respectively. The computed incremental shifts and other data were used to calculate the 1H and 13C NMR chemical shifts of the substituted compounds in three different ways. The calculated chemical shifts by the three methods compared well with each other and with the observed chemical shifts, testing the validity of the principle of additivity of the substituent effects in these compounds. The variation of 1H NMR chemical shifts of either the aromatic or N-H protons, with the substituents in N-(phenyl)- and N-(2/3/4-chloro/methylphenyl)-acetamides and substituted acetamides did not follow the same trend, while the variation of the 13C NMR chemical shifts of C-1 and C=O carbon atoms and those of alkyl carbon atoms of these compounds followed more or less the same trend.


1986 ◽  
Vol 51 (3) ◽  
pp. 621-635 ◽  
Author(s):  
Václav Křeček ◽  
Jiří Protiva ◽  
Miloš Buděšínský ◽  
Eva Klinotová ◽  
Alois Vystrčil

Reaction of amide I with nitrous acid gave the olefins II, III and IV. On allylic oxidation of olefin IV α,β-unsaturated ketone V is formed from which olefins VIII and IX were prepared by a sequence of further reactions. Addition of hydrogen to the double bond of olefin IV and α,β-unsaturated ketone V takes place on catalytic hydrogenation from the β-side and leads to derivatives with cis-annellated rings D/E. This made the preparation of hydrocarbons VI and VII epimeric on C(18) possible, which represent reference compounds for the study of the effect of substituents on the chemical shifts of the methyl groups and the saturated carbon atoms of 18αH and 18βH-lupane derivatives. The configuration of the hydroxyl group in epimers XI and XII were derived from 1H NMR spectra. Deuteration of olefins III, IV and IX gave deuteriohydrocarbons XVI to XVIII. The 1H, 13C NMR and mass spectra of the substances prepared are discussed.


1980 ◽  
Vol 58 (4) ◽  
pp. 361-368 ◽  
Author(s):  
Constantinos A. Tsipis ◽  
Constantinos A. Tsoleridis

Carbon-13 nmr chemical shifts of a number of E-silyl-alkenes containing the silyl substituent at an sp2 carbon atom are presented. Assignments of the chemical shifts have been made by noting systematic variations in the spectra with changes in substituents and by comparison of the chemical shifts to those of the corresponding unsubstituted alkenes. The substituent effects observed were explained on the basis of the π-acceptor ability of the silyl substituents and the structure of the molecules. Comparing the 13C nmr spectra of the E-silyl-alkenes and those of the corresponding unsubstituted alkenes, differential chemical shifts have been obtained which can be used as empirical substituent parameters for the prediction of the 13C nmr spectra of other E-silyl-alkenes not yet studied. It was also demonstrated that 13C nmr spectroscopy can be used without resorting to special techniques (gated decoupling and the addition of paramagnetics) as an alternative method to the 1H nmr for the quantitative analysis of mixtures of regio-isomer E-silyl-alkenes.


2005 ◽  
Vol 60 (1-2) ◽  
pp. 106-112 ◽  
Author(s):  
B. Thimme Gowda ◽  
Mahesha Shetty ◽  
K. L. Jayalakshmi

Twenty three N-(2-/3-substituted phenyl)-4-substituted benzenesulphonamides of the general formula, 4-X’C6H4SO2NH(2-/3-XC6H4), where X’ = H, CH3, C2H5, F, Cl or Br and X = CH3 or Cl have been prepared and characterized, and their infrared spectra in the solid state, 1H and 13C NMR spectra in solution were studied. The N-H stretching vibrations, νN−H, absorb in the range 3285 - 3199 cm−1, while the asymmetric and symmetric SO2 vibrations vary in the ranges 1376 - 1309 cm−1 and 1177 - 1148 cm−1, respectively. The S-N and C-N stretching vibrations absorb in the ranges 945 - 893 cm−1 and 1304 - 1168 cm−1, respectively. The compounds do not exhibit particular trends in the variation of these frequencies on substitution either at ortho or meta positions with either a methyl group or Cl. The observed 1H and 13C chemical shifts of are assigned to protons and carbons of the two benzene rings. Incremental shifts of the ring protons and carbons due to -SO2NH(2-/3-XC6H4) groups in C6H5SO2NH(2-/3-XC6H4), and 4- X’C6H4SO2- and 4-X’C6H4SO2NH- groups in 4-X’C6H4SO2NH(C6H5) are computed and employed to calculate the chemical shifts of the ring protons and carbons in the substituted compounds, 4-X’C6H4SO2NH(2-/3-XC6H4). The computed values agree well with the observed chemical shifts.


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