Solvent-Free Synthesis of Some1-Acetyl Pyrazoles

Abstract

ABSTRACT. Some N-acetyl pyrazoles including 1-(3-(3,4-dichlorophenyl)-5-(substituted phenyl)-4,5-dihydro-1 H-pyrazole-1-yl) ethanones have been synthesised by solvent free cyclization cum acetylation of chalcones like substituted styryl 3,4-dichlorophenyl ketones using hydrazine hydrate and acetic anhydride in presence of catalytic amount of fly-ash: H2SO4 catalyst. The yield of these N-acetyl pyrazole derivatives are more than 75%. The synthesised N-acetyl pyrazoline derivatives were characterized by their physical constants and spectral data

Infrared, ¹H and ¹³C NMR Spectral Studies of some 4-([1,1′-Biphenyl]-4-yl)-6-(Substituted Phenyl)-5,6-Dihydro-4H-1,3-Oxazine-2-Amines: Assessment of Substituent Effects

“…From the infrared spectra of synthesized oxazine derivatives, the characteristic stretches (ν, cm −1 ) of NH 2 , C=N and C-O-C were assigned and tabulated in Table 1. Using Hammett equation and single and multi-regression analysis [2,[15][16][17][18][19][20][21][22][23][24] of these data with Hammett substituent constants and Swain-Lupton's [26] parameters, the obtained statistical results are tabulated in Table 2. From the Table 2, the NH 2 stretches (ν, cm −1 ) gave satisfactory correlations with positive ρ values.…”

“…From 13 C NMR spectra, the chemical shifts (δ, ppm) of C=N, and C 4-6 carbons were assigned and are tabulated in Table 1. These chemical shifts were correlated with Hammett σ, σ + , σ I , σ R constants F and R parameters using single and multi-parameter regression analysis [2,[15][16][17][18][19][20][21][22][23][24]. The results of single and multi-parameter statistical analyses are presented in Table 2.…”

“…Numerous synthetic methods of oxazine derivatives were reported in literature such as solvent-free and solvent-assisted methods [11]. Correlation analysis was useful for prediction of reaction speeds, structural conformations of alkenes [12], alkynes [13], α,βunsaturated aldehydes [14], ketones [15], ω-substituted ketones [16] and its esters, halo acyl bromides [17], 1H pyrazoles [18] and its derivatives. Infrared spectroscopic frequencies were applied for s-cis and s-trans conformations of ground state equilibrium of unsaturated carbonyl systems with respect to carbonyl and vinyl groups [19].…”

Microwave Supported Synthesis and Antimicrobial Evaluation of Bis-Pyrazole Derivatives from N-Phenyl Glutarimides

“…On the other hand, the chalcone showed significant cytotoxic activities against cell line, human hepatocellular and lung carcinoma and breast cancer [13] and also potent microbial agents [14]. The clalcone based five membered pyrazoles are prepared by hydrazine hydrate or aromatic hydrazines in presence of sodium acetate [15], acetic acid [16,17] catalysts by conventional and microwave [18][19][20], facile grinding [21], chromine ring opening [22], solvent free [23], one pot tandem [24] and regioselective [25] methods so on. The pyrazoline derivatives states the reasonable antibacterial [26], antifungal [27][28][29] activities.…”

Infrared, ¹H and ¹³C NMR Spectral Studies of some 4-([1,1′-Biphenyl]-4-yl)-6-(Substituted Phenyl)-5,6-Dihydro-4H-1,3-Oxazine-2-Amines: Assessment of Substituent Effects

“…Numerous synthetic methods of oxazine derivatives were reported in literature such as solvent-free and solvent-assisted methods [11]. Correlation analysis was useful for prediction of reaction speeds, structural conformations of alkenes [12], alkynes [13], α,β-unsaturated aldehydes [14], ketones [15], ω-substituted ketones [16] and its esters, halo acyl bromides [17], 1H pyrazoles [18] and its derivatives. Infrared spectroscopic frequencies were applied for s-cis and s-trans conformations of ground state equilibrium of unsaturated carbonyl systems with respect to carbonyl and vinyl groups [19].…”