Synthesis and Application of Some Azo and Azomethine Dyes Containing Pyrazolone Moiety

3-Amino-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (1) was used as starting material for the synthesis of a number of azo compounds 3a—3c and azomethine derivative 4. The deblocking of 3a—3c and 4 gave rise to 5a—5c and 6 in which a free amino was revealed. The diazonium salts of 5a—5c and 6 were coupled with several phenols to produce a number of bis azo compounds 7a—7c and 8a—8c with azomethine in position 4 and azoic group in position 3. The prepared dyes were structurally confirmed by elemental analysis, spectral methods and applied to different fibers (wool, polyester and blend of wool/polyester) as disperse dyes and their fastness properties were measured.     

Synthesis,characterization, and dyeing performance of some azo thienopyridine and thienopyrimidine dyes based on wool and nylon

A string of novel heterocyclic mono azo dyes were synthesized and their utilization in dyeing different fabrics as wool and nylon were discussed. Thienopyridine azo dyes 4 and 6 were prepared by reaction of chloro acetamidederivative 2 with diamino compounds to yield 3 and 5 , followed by reaction with NaNO₂/HCl and coupling with nucleophilic reagent. One-pot reaction of chloro acetamide 2 with ammonium thiocyanat in solvent ethanol gave the unexpected thienopyrimidine derivative 7 , which contain two active sites, the former is primary amine that was able to form diazonium salt that coupled with N,N-dimethylaniline, resorcinol, and/or self-coupling to afford the azo dyes 8-10 , and the latter is active methylene group that underwent coupling with different diazonium salts to give the azo thienopyrimidine derivative dye 11-15 . The dyeing performance of these azo dyes had been investigated in terms of their dyeing behavior and fastness properties on different fabrics. Results showed that the color strength (K/S) values, as well as, washing, rubbing, and resistance to acid, alkali and light showed high efficiency of these heterocyclic mono azo dyes to dye wool rather than nylon fibers.     

Dyeing of multiple types of fabrics with a single reactive azo disperse dye

Three novel reactive azo disperse dyes were prepared using 7-acetamide-4-hydroxy-2-naphthalene sodium sulphate as the precursor. The structure of the dyes has the combined characteristics of reactive, disperse, and cationic dyes. Under alkaline conditions (pH 9), the dyes can be applied to cotton, silk, wool, and nylon. Under neutral conditions, they can be used to dye polyester. Under acidic conditions (pH 4.5), they can colour acrylic fabric after conversion of the tertiary amine group to the quaternary ammonium cation. The colour-fastness of the dyed fabrics were also evaluated.     

Regioselective synthesis of 1-aryl-3,4-substituted/annulated-5-(methylthio)pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/annulated pyrazoles

[reaction: see text] Highly efficient and regioselective synthesis of 1-aryl-3,4-substituted/annulated-5-(methylthio)pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/annulated pyrazoles has been reported via cyclocondensation of arylhydrazines with either alpha-oxoketene dithioacetals or beta-oxodithioesters.     

Synthesis of heterocyclic monoazo dyes derived from 1H-benzo[g]pyrazolo[3,4-b]quinoline-3-ylamine: their antimicrobial activity and their dyeing performance on various fibers

Heterocyclic monoazobenzoquinoline-based azo dyes have been derived by diazotization of 1H-benzo[g]pyrazolo[3,4-b]quinoline-3-ylamine with a variety of phenylpyrazolone-based coupling compounds. The synthesized dyes were characterized by determination of their percentage yield, by elemental analysis, and by UV?Cvisible, IR, and ¹H NMR spectroscopy. Dyeing performance on silk, wool, nylon, and polyester fibers was assessed. The fastness properties of the dyes on each fiber were moderate to excellent. The antimicrobial activity of the dyes at different concentrations were also examined, by use of the Kirby?CBauer disk diffusion method.     

Montmorillonite KSF clay-promoted synthesis of enantiomerically pure 5-substituted pyrazoles from 2,3-dihydro-4H-pyran-4-ones

2,3-Dihydro-4H-pyran-4-ones derived from d-glucal undergo rapid condensation with aryl hydrazines in the presence of montmorillonite KSF clay under mild conditions to afford a novel class of chiral 5-substituted pyrazoles in good yields with high selectivity. The stereochemical assignments of the products were achieved by NMR studies.     

Studies on heteroaromaticity. XV . the 1,3-dipolar cycloaddition reaction of 5-nitro-2-furyldiazomethane

The 1,3-dipolar cycloaddition reaction of 5-nitro-2-furyldiazomethane ( 1 ) with acrylonitrile, acrylamide, methyl acrylate, diethyl fumarate, methyl methacrylate and methyl cinnamate afforded the corresponding 3-substituted pyrazolines. ( 2a-f ). Similarly the pyrazoles ( 3b-d ) were prepared by addition of 1 to acetylenic compounds such as diethyl acetylenedicarboxylate, methyl phenylpropiolate and cyanoacetylene. Reaction of 1 with fumaronitrile and ω-nitro-styrene gave also the corresponding pyrazoles ( 3a and 3e ) instead of the pyrazolines. 3-(5′-Nitro-2′-furyl)-4-phenyl-5-carbomethoxypyrazoline ( 2f ) was oxidized with lead tetraacetate to the corresponding pyrazole ( 3f ), which was different from 3c , an addition product of 1 with methyl phenylpropiolate. 3-(5′-Nitro-2′-furyl)-5-carbamidopyrazoline ( 2b ) was pyrolyzed to the corresponding cyclopropane derivative 4 in low yield.     

A novel one-pot method for the preparation of pyrazoles by 1,3-dipolar cycloadditions of diazo compounds generated in situ

A convenient one-pot procedure for the preparation of pyrazoles by 1,3-dipolar cycloaddition of diazo compounds generated in situ has been developed. Diazo compounds derived from aldehydes were reacted with terminal alkynes to furnish regioselectively 3,5-disubstituted pyrazoles. Furthermore, the reaction of N-vinylimidazole and diazo compounds derived from aldehydes gave exclusively 3-substituted pyrazoles in a one-pot process.     

Polyurethanes as polymerizable dyes for hydrophobic polyester fabric

The present invention is to provide a novel benzothiazole-type polymerizable dye containing a urethane bond. A series of monomeric dyes have been prepared by diazotization of various 2-aminobenzothiiazole and coupled with Resorcinol. The polymeric dyes have been prepared by polycondensation of monomeric dyes with hexamethylene diisocyanate (HMDI), and they are characterized by molecular weight, non-aqueous conductometric titration, thermogravimetry analysis, IR, visible spectroscopy, and elemental analysis. The monomeric dyes have also been characterized by elemental analysis and IR spectra. The purity of all the dyes have been checked by thin layer chromatography, and their dyeing performance on nylon and polyester was assessed. The dyeing on polyester fiber had yellow, orange and pink shades with moderate to good light and wash fastness. Polymerizations of monomeric dyes with HMDI on dyed polyester have also been carried out. Color and dyeability of the polymeric dyes have been discussed by comparing them with their corresponding monomeric dyes. The percentage dye bath exhaustion and fixation on fiber have been found to be from good to very good. The dyeing of monomeric dyes showed very good color fastness properties, and their corresponding polymeric dyes showed excellent fastness to light, washing, perspiration, solvent resistance, and sublimation.     

Synthesis,Characterization of Novel Bisheteroaryl Bisazo Dyes,and Their Dyeing and Solvatochromic Behavior

4‐Phenyl‐2‐aminothaizole was diazotized and coupled with N‐(alkyl)‐2‐oxo‐3‐cyano‐4‐methyl‐6‐hydroxypyridine (2‐pyridone). The resultant dyes were named as N‐(alkyl)‐6‐hydroxy‐4‐methyl‐2‐oxo‐5‐((4‐phenylthiazole‐2‐yl)diazenyl)‐1,2‐dihydro pyridine‐3‐carbonitrite and duly characterized. The diazotized aryl amines were then coupled to a moiety of above‐mentioned dyes at 5‐position of thiazole. The obtained bisheteroaryl azo dyes were characterized by elemental analysis and spectral studies. Solvent effects on the visible absorption spectra of the dyes were evaluated. The color of the dyes is discussed with respect to the nature of the heterocyclic ring, aromatic amines, and substituents present therein. All these dyes were applied as disperse dyes on to polyester fabrics, and their fastness properties were evaluated. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:208–220, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21085     

Mass spectra of 5-styryl and 5-acylpyrazoles

High-resolution, electron-impact, mass-spectrometric measurements have been made on three types of pyrazoles. Type 1 comprised ethyl 5-styrylpyrazole-3-carboxylates having in the α-position of the styryl group either a hydrogen atom, a methyl, or a phenyl group. Type II were 1,3,5-trisubstituted pyrazoles having phenyl (or p-substituted phenyl) groups in position 1, amide or carboxylate groups in position 3, and styryl (or α-substituted styryl) groups in position 5. Type III differed from type II in possessing a readily cleaved acyl or aroyl group instead of the styryl group. The compounds containing styryl groups gave significant ions corresponding to the formation of polycyclic heteroaromatic rings, in addition to various other fragments derived from such rings. Intensities and accurate mass-measurements are given for all ions having intensities exceeding 5% of the base peak.     

A novel approach to the synthesis of 5-trifluoromethyl-3-substituted pyrazoles

The 3-cyano-4-trifluoromethyl-6-phenyl or substituted phenyl 2(1H) pyridones (1) on reaction with hydrazine hydrate, gave exclusively in 5-trifluoromethyl-3-substituted pyrazoles (3) through a novel method. A possible mechanistic pathway for change in the site of nucleophilic attack due to the CF₃ group in 2(1H) pyridones is described.     

Synthesis and antibacterial studies of azodispersed dyes derived from 2-(thiazol-2-yl)phthalazine-1,4-diones

Abstract  

A dibenzobarrelene derivative was used as key intermediate for the synthesis of 2-(4-(methyl/phenylthiaz-ol-2-yl)-2,3,4a,5,10,10a-hexahydro-5,10-benzenobenzo[g]phthalazine-1,4-diones. These compounds were coupled with the appropriate diazonium chlorides to give the corresponding 5-(arylazo)thiazole derivatives. The synthesized dyes were applied to polyester as disperse dyes, and their antibacterial, color measurement, and fastness properties were evaluated.     

Novel Approaches to Synthesis of 4-Alkyl-6-amino-5-cyano-3-methyl(propyl, phenyl)-2H,4H-pyrano[2,3-c]pyrazoles

We have obtained 4-alkyl-6-amino-5-cyano-3-methyl(propyl, phenyl)-2H,4H-pyrano[2,3-c]pyrazoles by reaction of 4-alkylmethylene-3-substituted 5-pyrazolones with malononitrile or cyanothioacetamide. We have used X-ray diffraction to study the structure of 6-amino-5-cyano-4-isopropyl(hexyl)-3-phenyl-2H,4H-pyrano[2,3-c]pyrazoles.     

Synthesis of Some Novel Biologically Active Disperse Dyes Derived from 4-Methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydro-pyridine-3-carbonitrile as Coupling Component and Their Colour Assessment on Polyester Fabrics

A series of novel azo-disperse dyes containing alkylhydrazonopyridinone structures were synthesized. 4-Methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-carbonitrile (8) is synthesized by one-pot synthesis using ethyl cyanoacetate, propylamine, and ethyl acetoacetate. Compound 8 is then coupled with aromatic and heteroaromatic diazonium salts to afford the corresponding aryl- and heteroaryl-4-methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-carbonitriles 12a,b and 13a-c. Structural assignments to the dyes were made using NMR spectroscopic methods. A high temperature dyeing method was employed to apply these dyes to polyester fabrics. Most of the dyed fabrics tested displayed very good light fastness levels and good wash fastness. Finally, the biological activity of the prepared dyes against Gram positive bacteria and Gram negative bacteria were evaluated.     

Straightforward transformation of isoxazoles into pyrazoles: renewed and improved

Isoxazoles bearing alkyl or carbamoyl groups were transformed into the corresponding pyrazoles in high yields by the treatment with hydrazine in methanol in the presence of a hydrogenation catalyst, e.g., Raney nickel, at ambient temperature. For the synthesis of N-substituted pyrazoles, hydrogenolysis of isoxazole followed by the treatment with substituted hydrazine was required. 3(5)-Aryl- or acylamido-substituted isoxazoles are less suitable for such transformations.     

Synthesis of 5-Substituted 1,3-Dimethylpyrazolo[4,3-e][1,2,4]triazines

A novel method for the synthesis of a new series of 5-substituted 1,3-dimethyl pyrazolo[4,3-e][1,2,4]triazines is described. The new synthetic strategy is based on the classical Bischler 1,2,4-benzotriazine synthesis. This approach involves the preparation of 5-hydrazinopyrazole from 5-chloro-1,3-dimethyl-4-nitropyrazole followed by acylation and nitro group reduction to form the corresponding 4-amino-3-(acylhydrazino)pyrazoles. Intramolecular oxidative cyclization of the latter derivatives, using polyphosphoric acid, produced the respective target pyrazolotriazines.     

Facile synthesis of novel CF3-substituted ring-fused furo[2,3-c]pyrazoles through Rh2(OAc)4 catalyzed [3+2] cycloaddition of 4-diazo-1-phenyl-3-(trifluoromethyl)-1H-pyrazol-5(4H)-one with aromatic alkynes

The Rh₂(OAc)₄ catalyzed [3+2] cycloaddition of 4-diazo-1-phenyl-3-(trifluoromethyl)-1H-pyrazol-5(4H)-one with aromatic alkynes was studied, and this protocol can be efficiently applied to the synthesis of the novel CF₃-substituted ring-fused furo[2,3-c]pyrazoles.     

New reaction of 1H-pyrazoles with selenium dioxide: one-pot synthesis of bis(1H-pyrazol-4-yl)selenides

A novel reaction between 3- and 3,5-substituted pyrazoles with selenium dioxide proceeds with formation of bis(3R,5R′-1H-pyrazol-4-yl)selenides in high yield. On this basis, an efficient one-pot synthetic procedure has been developed. In the case of the unsubstituted pyrazole a selenonium compound has been obtained. The identity and structure of the isolated selenium derivatives have been confirmed by spectral methods and their molecular structures investigated by X-ray analysis.     

Heterocyclic compounds from 2-(alkoxycarbonylcyanomethylene)-1,3-dioxolanes

2-(Alkoxycarbonylcyanomethylene)-1,3-dioxolanes reacted with hydrazines and hydroxylamine to yield 1-substituted 4-alkoxycarbonyl-5-amino-3-(2′-hydroxyethoxy)pyrazoles and 4-alkoxycarbonyl-5-amino-3-(2′-hydroxyethoxy)isoxazoles respectively. With guanidine and benzamidine 2-substituted (R = NH₂, C₆H₅) 5-cyano-6-(2′-hydroxyethoxy)pyrimidin-4-ones were obtained. Reaction of 2-(cyanomethoxycarbonylmethylene)-1,3-dioxolane with 1,3-diaminopropane afforded 2-(cyanomethoxycarbonylmethylene)-1,3-hexahydro-pyrimidine whereas treatment of the same compound with 4,5-dimethyl-1,2-phenylenediamine gave 2-(cyanomethoxycarbonylmethylene)-5,6-benzimidazoline. The structures of pyrazoles and pyrimidones were assigned on the basis of ¹H-{¹H} and ¹³C-{¹H}-nOe experiments.