Investigation of mesomorphic properties of new 1,3,4-thiadiazolines (which are synthesised via many steps in Scheme 1) was carried out in this study. These compounds are designed to have a heterocyclic unit, a carboxylate linkage group and a polar ether chain at the end of the molecule adjacent to the benzene ring, which enhance the dipolar interactions forces (varied from one to eight carbons) to investigate the association properties of their phases. The structure of the target compounds and the intermediates were confirmed by 1H NMR, 13C NMR, mass and FTIR spectral techniques. Polarised microscopic studies revealed that all the compounds in the series exhibited enantiotropic liquid crystalline properties. This was further confirmed using differential scanning calorimetric experiments. The synthesised compounds type [V]n in this study displayed different liquid crystalline mesophases and the homologous [V] having an alkoxy terminal group (n = 1–3) exhibited nematic phase, whilst the last derivatives of the series (4–8), displayed smectic A phase.
1,3,4-oxadiazole-5-thion ring (2) successfully formed at position six of 2-methylphenol and five of their thioalkyl (3a-e). Furthermore 6-(5-(Aryl)-1,3,4-oxadiazol-2-yl)-2-methylphenol (5a-i) were formed at position six by two method. The first method was from cyclization their corresponding hydrazones (4a-e) of 2-hydroxy-3-methylbenzohydrazide (1) using bromine in glacial acetic acid. The second method was from cyclization the hydrazide with aryl carboxylic acid in the presence of phosphorusoxy chloride. The newly synthesized compounds were characterized from their IR, NMR and mass spectra. The antioxidant properties of these compounds were screened by 2,2-Diphenyl-1-picrylhydrazide (DPPH) and ferric reducing antioxidant power (FRAP) assay
... Show More1, 3, 4-oxadiazole-5-thion ring (2) successfully formed at position six of 2-methylphenol and five of their thioalkyl (3a-e). Furthermore 6-(5-(Aryl)-1, 3, 4-oxadiazol-2-yl)-2-methylphenol (5a-i) were formed at position six by two method. The first method was from cyclization their correspondinghydrazones (4a-e) of 2-hydroxy-3-methylbenzohydrazide (1) using bromine in glacial acetic acid. The second method was from cyclization the hydrazide with aryl carboxylic acid in the presence of phosphorusoxy chloride. The newly synthesized compounds were characterized from their IR, NMR and mass spectra. The antioxidant properties of these compounds were screened by 2, 2-Diphenyl-1-picrylhydrazide (DPPH) and ferric reducing antioxidant power (FRAP) a
... Show MoreReaction of,2- [( 4- amio phenyl ) diazenyl] 1,3,4- thiadiazole -5- thiol (S1) with p- chlorobenzeldehyde,3,4 – dimethoxy benzaldehyde and pyrrol-2- carbonxaldehyde gave -5- [{4-(4-chlorobenzylidene amino) phenyl} diezenyl]-1,3,4- thiadiazole-2- thiol (S2),5-[{ 4-[(3,4- dimethoxybenzyldene )amino phenyl ] diazenyl)-1,3,4- thiadiazole-2-thiol,(S3) and -5- [4-(1,H – pyrrol -2- yl- methylene)amino phenyl] diazenyl)-1,3,4- thiadiazole-2- thiol (S4) respectively as schiff's bases compounds. On the same route-2-[(4-amino-1- naphthyl ) diazenyl] -1,3,4- thiadiazole -5- thiol (S5) reacts with –p- chloro benzaldehyde and –m- nitrobenzaldehyde to give the follwing schiff's bases -5-[{ 4-(4- chloro benzylidene ) amino -1- naphthyl} diazenyl]
... Show MoreThe organic compound imidazole has the chemical formula C3N2H4. Numerous significant biological compounds contain imidazole. The amino acid histidine is the most prevalent. The substituted imidazole derivatives have great potential for treating a variety of systemic fungi infections. Thiourea is an organosulfur compound with the formula SC(NH2)2. It is a reagent in organic synthesis. In this paper, some new imidazole and thiourea derivatives are synthesized, characterized, and studied for their biological activity. These new compounds were synthesized from the starting material terephthalic acid, which was transformed to corresponding ester [I] by the refluxing of diacid with methanol in the presence of H2SO4 as a catalyst, compound [I] con
... Show MoreCertain cyclic amine derivatives of metronidazole via acetate spacer were prepared. Cyclic amines used are piperidine and piperazine to improve the physicochemical properties and reduce some of metronidazole side effects. This is believed to be done by modification of its structural features to get prodrugs with improved properties over that of metronidazole. The present work includes esterification of metronidazole with choroacetic acid, N-alkylation of the cyclic amines by the halogenated ester and characterization of their structures by spectral(UV and IR) and elemental(CHN)analysis.The melting points, degree of solubilities and partition coefficients were also determined. Both metronid
... Show MoreIbuprofen is one of the most important members of NSAIDs, named aryl propionic acid derivative. Isatin (1H-indole-2,3-dione) is an important molecule of heterocyclic compounds that have many biological activities. This work illustrates the synthesis of new ibuprofen-isatin derivatives by connecting ibuprofen hydrazide with different isatin derivatives by a condensation reaction, followed by characterization by fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The anti-inflammatory activity was evaluated by using the egg-white induce edema method for all the synthesized compounds (5-8), the compounds 5 and 6 showed better anti-inflammatory activity than ibuprofen as a standard
... Show MoreIbuprofen is one of the most important members of NSAIDs, named aryl propionic acid derivative. Isatin (1H-indole-2,3-dione) is an important molecule of heterocyclic compounds that have many biological activities. This work illustrates the synthesis of new ibuprofen-isatin derivatives by connecting ibuprofen hydrazide with different isatin derivatives by a condensation reaction, followed by characterization by fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The anti-inflammatory activity was evaluated by using the egg-white induce edema method for all the synthesized compounds (5-8), the compounds 5 and 6 showed better anti-inflammatory activity than ibuprofen as a standard compoun
... Show MoreIn this time, most researchers toward about preparation of compounds according to green chemistry. This research describes the preparation of 2-fluoro-5-(substituted benzylideneamino) benzonitrile under reflux and microwave methods. Six azomethine compounds (B1-6) were synthesized by two methods under reflux and assisted microwave with the comparison between the two methods. Reflux method was prepared of azomethine (B1-6) by reaction of 5-amino-2-fluorobenzonitrile with some aldehyde derivatives with (50–100) mL of absolute ethanol and some quantity of GAA and time is limited between (2–5) hours with a yield between (60–70) percent with recrystallization for appropriate solvents. But the microwave-assisted method was synthesized of co
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