Zobrazeno 1 - 10
of 50
pro vyhledávání: '"Viera Knoppová"'
Publikováno v:
Collection of Czechoslovak Chemical Communications. 46:3110-3114
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 wi
Publikováno v:
Tetrahedron. 32:1411-1414
Two series of 5-nitro-2-furfurylarylsulphides 4a–4f and 5-nitro-2-furfurylarylsulphones 5a–5g were prepared by the reaction of 5-nitrofurfurylbromide 1 with 4-substituted thiophenols 2a–2f and with 4-substituted benzenesulphinic acids 3a–3g ,
Publikováno v:
Collection of Czechoslovak Chemical Communications. 46:515-519
Reaction of 4-X-benzyltriphenylphosphonium halides with 2-furaldehyde and subsequent Vilsmeier formylation gave 5-(4-X-styryl)-2-furaldehydes ( X = H, Cl, Br, CN, NO2, CH3, and COOCH3). The UV, IR and 1H-NMR spectra of the prepared substances are dis
Publikováno v:
Collection of Czechoslovak Chemical Communications. 49:984-991
Methyl 2-cyano-3-(4-bromo-5-R-X-2-furyl)-2-propenenitriles and 2-propenoates were prepared from 2-cyano-3-(4,5-dibromo-2-furyl)-2-propenenitrile and methyl 2-cyano-3-(4,5-dibromo-2-furyl)-2-propenoate and the respective nucleophiles R-XNa (X = S, R =
Autor:
Margita Margušová, Miroslav Dzuroška, Jaroslav Kováč, Rudolf Kada, Katarína Špirková, Viera Knoppová
Publikováno v:
Collection of Czechoslovak Chemical Communications. 50:459-469
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 h
Publikováno v:
Collection of Czechoslovak Chemical Communications. 45:910-913
Furancarboxylic acids were prepared by oxidation with Ag2O of the corresponding 5-(X-phenoxy)-2-furaldehydes (X = 4-OCH3, 4-SCH3, 3-NHCOCH3, 4-Cl, 4-Br, 4-COOC2H5, 3-NO2, and 4-NO2. The appearing pKa values of the synthesized acids were determined by
Publikováno v:
Collection of Czechoslovak Chemical Communications. 45:423-426
5-(4- Or 3-X-phenoxy)-2-furaldehydes were prepared from 5-bromo-2-furaldehyde and the respective sodium 4- or 3-X-phenolates (X = 4-Cl, 4-Br, 4-NO2, 4-CH3, 3-NO2, 4-CH3O, 4-COOC2H5, 4-SCH3, 3-NHCOCH3 in dimethyl sulfoxide. The transmission effect of
Publikováno v:
Collection of Czechoslovak Chemical Communications. 44:2417-2420
5-Nitro- and 5-bromo-2-furfurylidenemalonitriles react with secondary saturated amines in an SN reaction to replace bromo or nitro groups. The effects of nucleophilic reagent, solvent and temperature on the reaction rate were investigated. The result
Publikováno v:
Collection of Czechoslovak Chemical Communications. 43:3409-3413
Publikováno v:
Collection of Czechoslovak Chemical Communications. 39:773-778