- Regioselective synthesis of multisubstituted pyrazoles via cyclocondensation of β-thioalkyl-α,β-unsaturated ketones with hydrazines
-
Multisubstituted pyrazoles were efficiently synthesized by cyclocondensation of β-thioalkyl-α,β-unsaturated ketones with hydrazines under relatively mild conditions. A one-pot synthetic protocol through tandem Liebeskind-Srogl cross-coupling/cyclocondensation using a-oxo ketene dithioacetals as the starting materials was also realized for the same purpose.
- Jin, Weiwei,Yu, Haifeng,Yu, Zhengkun
-
experimental part
p. 5884 - 5887
(2011/12/02)
-
- Scope and limitations in the regioselective synthesis of 1,3,5-trisubstituted pyrazoles from β-amino enones and hydrazine derivatives. 13C-chemical shift prediction rules for 1,3,5-trisubstituted pyrazoles
-
β-amino enones react with hydrazine derivatives to give regioselectively 1,3,5-trisubstituted pyrazoles. The synthetic method only presents limitations when the β-substituent of the enone and the hydrazine substituent are bulky or possess an electron withdrawing character. Comparison of the 13C-NMR spectra of the seventy pyrazoles allowed us to estimate a 13C-chemical shift prediction rule for 1,3,5-trisubstituted pyrazoles, with deviations of less than ± 1 ppm.
- Alberola, Angel,Calvo Bleye, Luis,Gonza?lez-Ortega, Alfonso,Sa?daba, M.Luisa,San?udo, M.Carme
-
p. 331 - 352
(2007/10/03)
-
- Porphyrins with four azole substituents in meso positions: X-ray crystal structure of meso-tetrakis-(1-benzylpyrazol-4-yl)-porphyrin at 200 K
-
Several new porphyrins have been prepared in improved yields using an established method which was adapted to formylpyrazoles bearing on the pyrazole N1-nitrogen protective groups. The deprotection of N-para-methoxybenzyl and SEM protected meso
- Werner, Andreas,Sanchez-Migallon, Ana,Fruchier, Alain,Elguero, Jose,Fernandez-Castano, Cristina,Foces-Foces, Concepcion
-
p. 4779 - 4800
(2007/10/02)
-
- Orientation de la reaction d'alkylation des pyrazoles dans des conditions neutres et en catalyse par transfert de phase
-
The N-butylation and N-benzylation of nine pyrazoles bearing different substituents in positions 3 and 5 have been studied in neutral and basic medium (phase transfer catalysis).The orientation of the reaction depends strongly on the method used when the
- Tarrago, Georges,Ramdani, Abdelkrim,Elguero, Jose,Espada, Modesta
-
p. 137 - 142
(2007/10/02)
-