Reaction of β-alkoxyvinyl halomethyl ketones with cyanoacetohydrazide (original) (raw)
Related papers
Reaction of β-alkoxyvinyl halomethyl ketones with cyanoacetohydrazide
Journal of The Brazilian Chemical Society, 2008
The synthesis of thirteen 1-cyanoacetyl-5-hydroxy-5-halomethyl-1H-4,5-dihydropyrazoles from the reaction of 4-alkoxy-3-alken-2-ones [R3C(O)C(R2)=C(R1)(OR), where R3 = CF3, CCl3, CHCl2, CO2Et; R2 = H, Me; R1 = H, Me, Et, Pr, Pentyl, c-Hexyl, Ph, and R = Me, Et] with cyanoacetohydrazide is reported. In order to show the versatility of using the 1-cyanoacetyl-substituted pyrazoles as important building blocks in organic synthesis, some attempts to obtain pyrazole derivatives also are described.
N-[(5-Azido-1,3-diphenyl-1H-pyrazole-4-yl)methylene]-N-arylamines (4a-c) and N-[(5-Substituted-1,3-diphenyl-1H-pyrazole-4-yl)methylene]hydrazides (5a-e) were prepared from 5-azido-1,3-diphenyl-1H-pyrazole-4-carbaldehyde (3) and 5-chloro-1,3diphenyl-1H-pyrazole-4-carbaldehyde (2), respectively. Thermolysis of (4a-c) and (5d-e) afforded 5-arylamino-1,3-diphenyl-1H-pyrazol-4-carbonitriles (8a-c) and N-(4-cyano-1,3diphenyl-1H-pyrazol-5-yl)hydrazides (13a,b), respectively. N-[2-(5-Chloro-1,3-diphenyl-1H-pyrazol-4-yl)-4-oxo-thiazolidin-3-yl]amides (14a,b) and 3-acetyl-2-(5-chloro-1,3diphenyl-1H-pyrazol-4-yl)-5-aryl-2,3-dihydro-1,3,4-oxadiazoles (15a,b) were obtained from N-[(5-chloro-1,3-diphenyl-1H-pyrazole-4-yl)methylene]hydrazides (5a,b). 5-Azido-1,3-diphenyl-1H-pyrazol-4-carbaldehyde (3) gave unexpectedly 1-(1,3-diphenyl-1,6dihydropyrrolo-2,3-c]pyrazol-5-yl)ethan-1-one (17).
2014
One-pot synthesis of some 1 N-acetyl pyrazoles including 1-(3-(3,4-dimethylphenyl)-5-(substituted phenyl)-4,5-dihydro-1 H-pyrazole-1-yl) ethanones has been achieved via solvent-free microwave irradiation using substituted chalcones, hydrazine hydrate and acetic anhydride in the presence of catalytic amount of fly-ash: PTS catalyst. The yield of these 1 N-acetyl pyrazole derivatives is more than 75%. The synthesized 1 N-acetyl pyrazoline derivatives were characterized by their physical constants and spectral data. The infrared spectral mC‚N and C‚O (cm À1) frequencies, NMR chemical shifts (d, ppm) of H a , H b , H c , CH 3 protons, C‚N, C‚O and CH 3 carbons of 1-(3-(3,4-dimethylphenyl)-5-(substituted phenyl)-4,5-dihydro-1 H-pyrazole-1-yl) ethanones have been assigned and correlated with Hammett substituent constants and Swain-Lupton's parameters using single and multi-regression analysis. From the results of statistical analyses, the effect of substituents on the above group frequencies and chemical shifts of the acetylated pyrazoles were discussed.
Bulletin of the Chemical Society of Ethiopia, 2012
Starting from 2-acetylbenzofuran derivatives 1a-d, methyl/ethyl 4-substituted/unsubstituted benzofuran-2-yl)-2,4-dioxobutanoate 2a-d and 3a-d have been synthesized by Claisen's condensation reaction with diethyloxalate. The transesterified product, 1,3-diketoester 2a-d on condensation with phenyl hydrazine undergo cyclization to afford the corresponding methyl 5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carboxylate 4a-d, which upon further condensation with hydrazine hydrate yielded 5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide 5a-d. The structures of the newly synthesized compounds 2a-d, 3a-d, 4a-d and 5a-d were characterized by their elemental analysis and spectral studies such as IR, 1 H NMR, 13 C NMR and MS. All the synthesized compounds were screened for their antimicrobial activity. Most of the synthesized compounds showed high sensitivity against the selected bacteria and fungi at various concentrations.