Kinetic and spectral studies on 5-phenoxy-2-furaldehydes and their condensation products

1981 ◽  
Vol 46 (2) ◽  
pp. 506-514 ◽  
Author(s):  
Viera Knoppová ◽  
Miloslava Dandárová ◽  
Jaroslav Kováč
Keyword(s):  
Substitution Reaction ◽  
Nmr Spectra ◽  
Furan Ring ◽  
Point Of View ◽  
Spectral Studies ◽  
Reaction Site ◽  
Cyclic Amines ◽  
H Nmr ◽  
Condensation Products ◽  
Kinetics Of

The base-catalyzed reaction of 5-(4- or 3-phenoxy)-2-furaldehydes (X = 4-OCH3, 4-CH3, 4-Cl, 4-NO2, 3-NO2, 4-Br, 4-COOC2H5, 3-NHCOCH3, 4-SCH3) with malonodinitrile in ethanol gave the corresponding condensation products. The course of the reaction has been monitored kinetically. The kinetics of the nucleophilic substitution reaction at the position 5 of the furan ring of the obtained 2-cyano-3-(5-X-phenoxy-2-furyl)acrylonitriles with secondary cyclic amines (piperidine, morpholine, pyrrolidine) has been studied. The effect of X across the oxygen bridge upon the reaction site is discussed from the point of view of kinetics of the reaction. 1H-NMR spectra of the starting aldehydes and of the formed condensation products have been measured.

Transmission of polar effects arcoss the CH=CH link in styrylfuran system

1981 ◽  
Vol 46 (12) ◽  
pp. 3110-3114
Author(s):  
Viera Knoppová ◽  
Anton Beňo ◽  
Miloslava Dandárová ◽  
Jaroslav Kováč
Keyword(s):  
Thermodynamic Parameters ◽  
Substituent Effect ◽  
Nmr Spectra ◽  
Aldehyde Group ◽  
Point Of View ◽  
Polarographic Reduction ◽  
Transmission Coefficients ◽  
H Nmr ◽  
Polar Substituent ◽  
Kinetics Of

Transmission of polar substituent effect through the vinylidene grouping in 5-(4-X-styryl)-2-furaldehydes (X = H, Cl, Br, COOCH3, CN and NO2) was studied by polarographic reduction of the aldehyde group as well as by kinetics of their condensation with malononitrile. The obtained transmission coefficients π' were compared with the corresponding values for systems, containing other links between the benzene and furan nuclei. Thermodynamic parameters of the condensation with malononitrile were determined. The transmission of polar effects is discussed also from the point of view of 1H NMR spectra.

scholarly journals Synthesis and Antimicrobial Screening of Novel 4-Substituted Phenyl-5-[1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-yl]-2H-1,2,4-triazole-3-thiones

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Namratha Bhandari ◽  
Santosh L. Gaonkar
Keyword(s):  
Convenient Method ◽  
Nmr Spectra ◽  
Spectral Studies ◽  
Antimicrobial Screening ◽  
Antifungal Activities ◽  
H Nmr ◽  
Antibacterial And Antifungal Activities ◽  
Elemental Analyses ◽  
Antibacterial And Antifungal ◽  
C Nmr

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.

The 1H NMR spectra and the conformation of 1,6-anhydro-β-D-hexopyranoses and their triacetates

1979 ◽  
Vol 44 (6) ◽  
pp. 1949-1964 ◽  
Author(s):  
Miloš Buděšínský ◽  
Tomáš Trnka ◽  
Miloslav Černý
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Shift Reagent ◽  
Point Of View ◽  
Coupling Constants ◽  
Lanthanide Shift Reagent ◽  
Pyranose Ring ◽  
H Nmr ◽  
Vicinal Coupling Constants

The 1H NMR spectra of 1,6-anhydro-β-D-hexopyranoses and their triacetates, measured in hexadeuteriodimethyl sulfoxide or deuteriochloroform, confirmed the existence of these compounds in 1C4(D) conformations, with the pyranose ring partly planarized in dependence on the configuration of the substituents in positions C(2), C(3) and C(4). The effects of the substituents on the chemical shifts and the adjusted relationship for the dependence of vicinal coupling constants on the torsion angle are discussed in detail from the point of view of the determination of the configuration and the conformation of 1,6-anhydro-β-D-hexopyranoses and their derivatives. The 1H NMR spectra of triacetates were also measured in the presence of the lanthanide shift reagent, tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione) europium (III) [Eu.(FOD)3].

Preparation of pyridinium salts of 2-furane derivatives

1984 ◽  
Vol 49 (11) ◽  
pp. 2485-2491 ◽  
Author(s):  
Miroslav Kríž ◽  
Jaroslav Kováč ◽  
Vladimír Mlynárik
Keyword(s):  
Nucleophilic Substitution ◽  
Substitution Reaction ◽  
Nmr Spectra ◽  
Nucleophilic Substitution Reaction ◽  
Pyridinium Salts ◽  
H Nmr ◽  
C Nmr

Pyridinium salts have been prepared by nucleophilic substitution reaction of 5-halogeno-2-furane derivatives with pyridine and its 3- and 4-substituted derivatives, where R = 3-methyl, 3-ethyl, 3-amino, 3-methoxycarbonyl, 3-aminocarbonyl, 4-amino, 4-aminocarbonyl, 4-phenoxy, and 3,4-dimethyl, and structure of the derivatives prepared has been confirmed by their 1H NMR and 13C NMR spectra.

Stereochemistry and kinetics of amines addition to acetylenic esters

1991 ◽  
Vol 69 (9) ◽  
pp. 1445-1449 ◽  
Author(s):  
Saber M. Sharaf ◽  
Samir K. El-Sadany ◽  
Ezzat A. Hamed ◽  
Abdel-Hamid A. Youssef
Keyword(s):  
Key Words ◽  
Nucleophilic Addition ◽  
Nmr Spectra ◽  
Acetylenic Esters ◽  
H Nmr ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Step Mechanism

The reactions of a series of methyl para-substituted phenylpropiolates 1a–e with piperidine, morpholine, and diethylamine in methanol and dimethylformamide (DMF) have been studied and their rates measured. The products were methyl β-(N,N-dialkylamino)-p-substituted cinnamates 2–4a–e. 1H NMR spectra were used to determine the configuration of the products. The ρ values in methanol ranged between 0.34 and 1.24 whereas in DMF they were between 0.85 and 1.88. The values of ΔS≠ favor a bimolecular rate-limiting step mechanism. Key words: nucleophilic addition to acetylenic esters.

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

2013 ◽  
Vol 23 ◽  
pp. 109-116
Author(s):  
Ganesamoorthy Thirunarayanan
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Statistical Analyses ◽  
Spectral Studies ◽  
Ir And Nmr Spectra ◽  
Effect Of Substituents ◽  
H Nmr ◽  
Substituent Constants ◽  
C Nmr

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.

A study of reactions of 5-substituted furfurylidene derivatives with secondary amines

1985 ◽  
Vol 50 (2) ◽  
pp. 459-469 ◽  
Author(s):  
Katarína Špirková ◽  
Rudolf Kada ◽  
Jaroslav Kováč ◽  
Viera Knoppová ◽  
Miroslav Dzuroška ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Secondary Amines ◽  
H Nmr ◽  
Kinetics Of

The paper describes preparation of 5-bromo-, 5-nitro-, 5-phenylsulphonyl-, and 5-phenylthio-2-furfurylidene derivatives and investigation of their reactions with N-phenylpiperazine, morpholine, piperidine, and pyrrolidine. Kinetics of the reactions have been followed, and UV, IR, and 1H NMR spectra of the compounds produced are interpreted.

X+ transfer from the halonium ions of adamantylideneadamantane to acceptor olefins. The possibility of chiral induction in the transfer process

1997 ◽  
Vol 75 (12) ◽  
pp. 1844-1850 ◽  
Author(s):  
Alexei A. Neverov ◽  
Theresa L. Muise ◽  
R.S. Brown
Keyword(s):  
Nmr Spectra ◽  
Room Temperature ◽  
Reaction Rate ◽  
Methyl Groups ◽  
Kinetic Behavior ◽  
Methyl Group ◽  
Chiral Induction ◽  
H Nmr ◽  
Group 12 ◽  
Kinetics Of

The bromonium ion of adamantylideneadamantane (Ad=Ad-Br+) has been used to induce the bromocyclization of a 4-pentenyl glycoside (10) and a 5-hexenyl glycoside (11) in dichloroethane. The kinetics of these processes have been studied at 25 °C in the presence of varying [Ad=Ad] and, in the case of the transfer to 10, in the presence of pentanol. The second-order rate constants for bromocyclization of these two alkenes are (1.04 ± 0.06) × 10−1 M−1 s−1 and (5.34 ± 0.2) × 10−1 M−1 s−1, respectively, and in no case does added Ad=Ad or pentanol alter the reaction rate. The kinetic behavior is interpreted in terms of cyclization occurring directly from a 1:1 complex of Ad=Ad-Br+ and 10 or 11. The chiral induction for the bromocyclization of 10 promoted by AdAd-Br+ was measured at 20% e.e., the (−)-(S)-tetrahydrofurfuryl bromide being the dominant stereoisomer. Ad=Ad molecules substituted at one of the homoallylic carbons by an axial methyl group (12), or by two methyl groups (axial and equatorial), were synthesized and the 1H NMR spectra of their bromonium ions is given. These materials are not stable for prolonged times at room temperature. A limited kinetic study of the reaction of 12-Br+ and 4-pentenol indicated that the Br+ transfer is 500 times faster than the comparable transfer from Ad=Ad-Br+ to 4-pentenol. The possibility of using these materials to induce chiral bromocyclization is discussed. Keywords: bromonium ion, halonium, transfer, chiral, adamantylideneadamantane.

scholarly journals Triphenylphosphine complexes of cadmium(II) perchlorate, nitrate, and trifluoroacetate preparation, characterization, and spectral studies

1981 ◽  
Vol 59 (23) ◽  
pp. 3267-3272 ◽  
Author(s):  
Ram G. Goel ◽  
Narendra K. Jha
Keyword(s):  
Solid State ◽  
Elemental Analysis ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Ionic Species ◽  
Spectral Studies ◽  
Spectral Measurements ◽  
Coordinate Structure ◽  
H Nmr ◽  
Metal Ligand

1:2 complexes, CdX2(PPh3)2, where X = ClO4, NO3, CF3CO2 and 1:1 complex, Cd(CF3CO2)2PPh3, have been isolated and characterized by elemental analysis and by vibrational and 31P—{lH} nmr spectral measurements. Conductance measurements show that the complexes behave as non-ionic species in dichloromethane. The vibrational spectra of the perchlorato complex are consistent with a six-coordinate structure in the solid state as well as in solution but it is difficult to deduce the structures of the nitrato and trifluoroacetato complexes from the spectral data. Assignments for the metal–ligand stretching frequencies for all the four complexes have been proposed. The 3lP—{1H} nmr spectra of the four complexes have been discussed. Formation of the 1:3 and 1:4 complexes, Cd(ClO4)2(PPh3)3 and Cd(ClO4)2(PPh3)4, in solution, has also been established by 31P—{lH} nmr spectral measurements.

1H and 13C NMR study of (X-phenyl)-5-nitro-2-furylvinyl ethers

1980 ◽  
Vol 45 (12) ◽  
pp. 3557-3563 ◽  
Author(s):  
Miloslava Dandárová ◽  
Jaroslav Kováč ◽  
Daniel Végh
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Furan Ring ◽  
Chemical Shifts ◽  
1H And 13C Nmr ◽  
H Nmr ◽  
Nmr Study ◽  
Hammett Σ Constants ◽  
C Nmr

Reaction of 5-nitro-2-furylvinyltrimethylammonium bromide with substituted phenolates gave (E)- and (Z)-(X-phenyl)-5-nitro-2-furylvinyl ethers. The preffered s-cis and s-trans orientations of the furan ring in Z and E isomers, respectively, were determined by 1H NMR spectroscopy. To study the extent of p-π conjugation, 13C NMR spectra of compounds under investigation have also been measured and interpreted. Chemical shifts for ethylenic carbons and protons were correlated with Hammett σ constants.

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