Condensation Of O-phenylenediamine Research Articles

Polyethylene Glycol and Montmorillonite Clay Anchored Schiff Base Ligand–Metal Complexes

Three ligands were synthesized through condensation of o-phenylenediamine with salicylaldehyde (ligand 1) and 2-hydroxy-1-naphthaldehyde (ligand 2) and of 1,8-diaminonaphthalene with 2-hydroxy-1-naphthaldehyde (ligand 3) in 1:2 molar ratio; the ligands were characterized using NMR and FTIR techniques. The 1:1 complexes of ligand 1 with FeCl3 and CoSO4; ligand 2 with FeCl3, CoSO4·6H2O, and CoCl2·6H2O; and ligand 3 with FeCl3 were prepared and characterized using FTIR and XRD techniques. These ligand–metal complexes were then anchored on polyethylene glycol (PEG, MW = 6000), montmorilonite (MMT), and organically modified montmorillonite (OMMT, Closite30B) clays and characterized by FTIR. The spectral data of the ligands and their complexes have been explained in terms of structural changes occurring due to complexation. The XRD data indicated that anchoring on the three supports resulted in the reduction the crystal size providing higher surface area to volume ratio and, hence, potentially enhanced catalytic activity. Additionally, catalytic activity of the complexes has been proven by chemically fixing carbon-dioxide to propylene carbonate using propylene oxide.

Synthesis and Properties of Heterocyclic Acene Diimides

A series of heterocyclic acene diimides were synthesized effectively based on the condensation of o-phenylenediamine, 1,2-benzenedithiol, and 2-aminothiophenol with 2,3,6,7-tetrabromo-1,4,5,8-naphthalene tetracarboxylic diimide. The diimides exhibit interesting optical and electrical properties with one of them showing a hole mobility up to 0.02 cm(2) V(-1) s(-1).

Eco-Friendly Synthesis of 2-Substituted Benzimidazoles Using Air as the Oxidant

A simple, environmentally friendly procedure for the synthesis of 2-substituted benzimidazoles by the one-pot condensation of o-phenylenediamines with aromatic aldehydes using continuous bubbling of air in absolute ethanol at room temperature is described. The simplicity of the system, mild conditions, involvement of a non-toxic and practically inexhaustible oxidant, easy and quick isolation of the products, and moderate to good yields are the main advantages of this procedure.

Synthesis and anticonvulsant activity of various mannich and schiff bases of 1,5-benzodiazepines.

Benzodiazepines have a various behavioral effects in addition to their anxiolytic action. There is every reason to believe that the BZ/GABA receptor complex is involved in these effects, since GABAmimetic manipulations modify the effect of BZ in tests of convulsive activity, motor function, and appetitive behavior. 1,5-Benzodiazepines are biologically important molecules and are extensively used clinically as analgesic, hypnotic, sedative, and antidepressive agents. Hence, 1,5-Benzodiazepines were synthesized by condensation of o-phenylenediamine and ketones, for example, cyclohexanone and acetone in presence of sulfated zirconia (catalyst). Mannich bases were synthesized with acetophenone, p-nitroacetophenone, p-chloroacetophenone, and formaldehyde. Schiff bases were synthesized using Mannich base of 1,5-benzodiazepines with p-chloroaniline and p-chlorophenylsemicarbazide in the presence of glacial acetic acid. All the synthesized compounds were characterized by 1H NMR and IR spectral analyses. All the synthesized derivatives were evaluated at the dose of 30 mg/kg b.w for anticonvulsant activity by isoniazid induced convulsion model, and the compounds NBZD-3 and NBZD-8 were found to be the most active among all compounds. Among all the synthesized derivatives, compounds NBZD-13 and NBZD-17 were found to be the most active among all compounds using thiosemicarbazide induced model. Although NBZD-8, NBZD-10, and NBZD-18 are the compounds which had shown good anticonvulsant activity and have an advantage over that, they were not sedative.

SiO2/H2SO4: An Efficient Catalytic System for Solvent-free 1, 5-benzodiazepines Synthesis

1, 5-Benzodiazepines have been investigated extensively by organic chemists due to their medicinal and pharmacological properties. These compounds are synthesized by condensation of o-phenylenediamines with carbonyl compounds in the presence of acid catalysts. During our studies on the application of silica resin with acid functional moieties, we found that SiO2/H2SO4 mixture is a simple and efficient catalyst for this method under microwave irradiation. The reaction was carried out simply by grinding SiO2/H2SO4 mixture with o-phenylenediamine, and ketone in the mortar; then the mixture was poured out into a sealed flask. Subsequently, it was irradiated in a microwave oven. In this method a series of cyclic and acyclic ketones underwent above conversion to form corresponding 1, 5-benzodiazepines. In conclusion, this method is a simple, rapid, and high yielding reaction (78-95%).

Simple and Mild Protocol for Synthesis of 1,2-Disubstitued Benzimidazoles Using SBA-15-Supported Poly(4-styrenesulfonyl(perfluorobutylsulfonyl)imide) Catalyst

A simple method for the synthesis of several 1,2-disubstituted benzimidazoles catalyzed by strongly acidic SBA-15-supported poly(4-styrenesulfonyl-(perfluorobutylsulfonyl)imide) is described. The protocol furnished the products in moderate yield and good selectivity in the condensation of o-phenylenediamine with structurally diverse aldehydes under mild conditions.

Synthesis & Analgesic Activity of Mannich & Schiff Bases of 1,5- Benzodiazepines

: Benzodiazepines and their polycyclic derivatives are a very important class of bioactive compounds. They are finding numerous new applications and are widely used as anticonvulsant, anti-inflammatory, analgesic, hypnotic, sedative, and antidepressive agents. Hence 1,5-benzodiazepines were synthesized by condensation of o-phenylenediamine and ketones e.g., cyclohexanone in presence of Sulfated Zirconia (catalyst).Mannich bases were synthesized with acetophenone, p-nitroacetophenone, p-chloroacetophenone and formaldehyde. Schiff bases were synthesized using Mannich base of fused ring 1,5-benzodiazepines with p-chloroaniline and p-chlorophenylsemicarbazide in presence of glacial acetic acid. All the synthesized compounds were characterized by 1 H NMR and IR spectral analysis. Synthesized compounds were screened Analgesic ( both central and peripheral activity ) . Compounds NBZD-1. NBZD-3, NBZD-6, NBZD-11, were found to have good peripheral analgesic activity and NBZD-6, NBZD-8, NBZD-9, with good central analgesic activity. © 2011 IGJPS. All rights reserved.

Synthesis of 1,5-Benzodiazepine and Its Derivatives by Condensation Reaction Using H-MCM-22 as Catalyst

A simple and versatile method for the synthesis of 1,5-benzodiazepines is via condensation of o-phenylenediamines (OPDA) and ketones in the presence of catalytic amount of H-MCM-22 using acetonitrile as solvent at room temperature. In all the cases, the reactions are highly selective and are completed within 1–3 h. The method is applicable to both cyclic and acyclic ketones without significant differences. The reaction proceeds efficiently under ambient conditions with good-to-excellent yields.

Selective Synthesis of 2‐Aryl‐1‐benzylated‐1H‐benzimidazoles

AbstractAn efficient and simple procedure was developed for the green synthesis of various 2‐aryl‐1‐ben‐zylated‐1H‐benzimidazoles in high yields by condensation of o‐phenylenediamine with aldehydes with P2O5/SiO2 as catalyst under solvent‐free and ambient conditions.

ChemInform Abstract: Catalyst‐Free Synthesis of Benzodiazepines and Benzimidazoles Using Glycerol as Recyclable Solvent.

We described herein the use of glycerol as solvent in the catalyst-free synthesis of benzodiazepines and benzimidazoles. This simple and efficient method furnishes the corresponding 1-H-1,5-benzodiazepines and 1,2-disubstituted benzimidazoles in good yields by the condensation of o-phenylenediamine with several ketones and aldehydes, respectively. In addition, glycerol can be easily re-utilized for further condensation reactions up to four times without lost of activity.

Novel Method for the Syntheses of 2-Substituted Benzimidazoles Using Ti(IV) Isopropoxide and Cumene Hydroperoxide

Various 2-substituted benzimidazoles were prepared in one pot by condensation of o-phenylenediamine with an appropriate aldehyde in good to excellent yields using a mixture of Ti(IV) isopropoxide and cumene hydroperoxide.

ChemInform Abstract: Citric Acid: An Efficient and Green Catalyst for Rapid One‐Pot Synthesis of Quinoxaline Derivatives at Room Temperature.

Abstract The condensation of o-phenylenediamines with 1,2-dicarbonyl compounds in the presence of citric acid afforded the corresponding quinoxaline derivatives in higher yields at room temperature in ethanol, and most of the reactions were completed in less than 1 min.

Catalyst-free synthesis of benzodiazepines and benzimidazoles using glycerol as recyclable solvent

We described herein the use of glycerol as solvent in the catalyst-free synthesis of benzodiazepines and benzimidazoles. This simple and efficient method furnishes the corresponding 1-H-1,5-benzodiazepines and 1,2-disubstituted benzimidazoles in good yields by the condensation of o-phenylenediamine with several ketones and aldehydes, respectively. In addition, glycerol can be easily re-utilized for further condensation reactions up to four times without lost of activity.

An efficient and reusable heterogeneous catalyst Animal Bone Meal for facile synthesis of benzimidazoles, benzoxazoles, and benzothiazoles

A library of benzimidazoles, benzoxazoles, and benzothiazoles was efficiently synthesized by condensation of o-phenylenediamine, o-aminophenol, and o-aminothiophenol respectively with aromatic aldehydes in the presence of catalytic amounts of Animal Bone Meal (ABM) and Lewis acids doped ABMs. Reactions were conducted under reflux conditions in air. The remarkable features of this new protocol are high conversion, short reaction times, and cleaner reaction profiles, straightforward procedure, and reduction in catalyst toxicity.

Synthesis of 2-Arylbenzimidazoles in Water

A simple and efficient procedure for the synthesis of 2-arylbenzimidazoles through a one-pot condensation of o-phenylenediamines with aryl aldehydes in water is described. Short reaction time, large-scale synthesis, easy and quick isolation of the product, and excellent yield are the main advantages of this procedure.

Citric acid: An efficient and green catalyst for rapid one pot synthesis of quinoxaline derivatives at room temperature

Abstract The condensation of o-phenylenediamines with 1,2-dicarbonyl compounds in the presence of citric acid afforded the corresponding quinoxaline derivatives in higher yields at room temperature in ethanol, and most of the reactions were completed in less than 1 min.

Amberlite IR-120 catalyzed, microwave-assisted rapid synthesis of 2-aryl-benzimidazoles

An expeditious synthesis of 2-aryl-benzimidazoles by the condensation of o-phenylenediamine with various araldehydes is described. This greener protocol is catalyzed by Amberlite IR-120, and proceeds efficiently in the absence of any organic solvent under microwave irradiation within 3–5min.

Synthetic Utilities of o-Phenylenediamines: Synthetic Approaches for Benzimidazoles, Quinoxalines and Benzo[1,5]diazepines

This review represents the methods developed for the synthesis of benzimidazoles, quinoxalines and benzo(1,5)diazepines from the condensation of o-phenylenediamines with a variety of electrophilic reagents. Abstract Published data over the last years on the methods of synthesis and biological applications of azolylthiazoles are reviewed here for the first time till 2011. The review was classified according to the type of azole ring linked to thiazole. Abstract A new 1,3-benzoxazine nuclei-based fluorescent system is presented. The photophysical aspects are briefly discussed. The results suggested that the presence of oxazinic methylenes is necessary for fluorescence to be present. Abstract An efficient and mild procedure for the decarboxylative cyanomethyl esterification of arylmalonic acids has been developed. The reaction can be performed at room temperature by using chloroacetonitrile and 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) in toluene, and the desired arylacetic acid cyanomethyl esters are obtained in high yields within a short period of time.

ChemInform Abstract: Crystal Structures of H2(Me2dibenzo(14)tetraene)N4 and H2(Me2dixylyl( 14)tetraene)N4: New Tetraaza Macrocycles.

Crystal structures are reported for H2[Me2dibenzo[14]tetraene]N4(I) and H2[Me2dixylyl[14]tetraene]N4(II), prepared by the condensation of o-phenylenediamine and dimethyl-o-phenylenediamine with 3-ethoxy-2-methylacrolein in dimethylformamide. The space groups are P21/n, with cell constants of a= 9.940(4)A, b= 5.242(2)A, c= 15.329(5)A, B= 94.01 (3)°, Z= 2 for I, (C20H20N4), and a= 7.309(1)A, b= 13.712(2)A, c= 10.010(3)A, B= 90.61(2)°, Z= 2 for II, (C2H28N4). The macrocycles possess a near-planar structure with the largest deviation of any non-hydrogen atom from the least-squares molecular plane being 0.117 A for macrocycle I. The N-to-centre distance (RH) of 1.92 A found in both I and II is smaller than that found in porphyrins and non-conjugated N4 14-membered macrocyclic rings such as cyclam, but very similar to the value found in phthalocyanines.

Synthesis and photophysical properties of a series of thermally stable terphenyl-bridged bisbenzimidazoles

Nine novel terphenyl-bridged bisbenzimidazoles were synthesized in high yield by the condensation of o-phenylenediamines and terphenyl dinitriles in the presence of polyphosphoric acid. The bisbenzimidazoles are thermally robust with high decomposition temperatures (>346 °C) and high melting transitions and emit blue light at ∼410 nm with fluorescence quantum yield >0.4 in solution. Electrochemical studies indicate that the novel bisbenzimidazoles have a formal reduction potential in the range of −1.44 to −1.55 V and estimated electron affinities (lowest unoccupied molecular orbital levels) of 3.09–3.24 eV. The results indicate their potential use as blue-emitting materials in organic light-emitting diodes.