4-(((4-hydroxy-3,5-dimethoxybenzyl)oxy)methyl)benzoic acid was synthesized from multisteps and converted to their corresponding hydrazide. The corresponding hydrazide was cyclized to their corresponding 5-amino-1,3,4-oxadizole. Newly Schiff bases (7a-7e) were synthesized from reaction the 5-amino-1,3,4-oxadizole with several substituted of 4-hydroxybenzylaldehyde. The resulting compounds were characterized based on their IR, 1H-NMR, 13C-NMR, and HRMS data. 2,2-Diphenyl-1-picrylhydrazide (DPPH) and ferric reducing antioxidant power (FRAP) assays were used to test the antioxidant properties of the synthesized compounds. Compound 7d and 7e exhibited significant free-radical scavenging ability in both assays.

Some new 2,5-disubsituted-1,3,4-oxadiazole derivatives with azo group were synthesized by known reactions sequence . The structure of the synthesized compounds were confirmed by physical and spectral means .

In this research various of 2,5-disubstituted 1,3,4-oxadiazole (Schiff base, oxo-thiazolidine , and other compounds) were synthesized from 2,5-di(4,4?- amino-1,3,4-oxadiazole ) which use quently synthesized from mixture of 4-amino benzoic acid and hydrazine in the presence of polyphosphorus acid. The synthesized compounds were characterized by using some Spectral data (UV, FT-IR, and 1H-NMR).

  Two series of Schiff Bases and 2,3-disubstituted-1,3-thiazolidin-4-one derivatives  were synthesized . Reaction of 2-mercaptobenzothiazole with α-chloro acetic acid gave compound[I]. Esterification of carboxylic moity of compound [I] , using absolute methanol in the presence of conc . H2SO4 yielded acorresebonding ester  [II] , wich was condensation with hydrazine hydrate to give acid hydrazide [III] . The new Schiff bases [V]n were synthesized by reaction of acid hydrizide with dialdehyde [IV]n  in the presence of glacial acetic acid . The thiazolidinone derivatives [VI]n  have been obtained from the azomethines through the addition of thioglycolic acid . Their chemical structures have been confirmed by mel

Two new nonsymmetrical mesogenic homologous series of terminal substituent ether (series [Vn]) and carboxy (series [VIn]) incorporating azobenzene and 1,3,4-oxadiazole group were synthesized. Both series have been All compounds thus isolated were purified and characterized by elemental analysis, Fourier Transform Infrared Spectroscopy, 1H NMR, along with thermal analysis and texture observation using Differential Scanning Calorimetry (DSC) and Polarizing Optical Microscopy (POM), respectively. All compounds of the first series exhibited liquid crystalline properties. The homologues [V1]-[V3] display a nematic mesophase, the compounds [V4]-[V7] exhibit a dimorphism behavior, nematic (N) and smectic A (SmA) mesophases, the compounds [V8] and

A series of new Bis-1,4-Butane -1,3,4 – Oxadizole derivatives [III a-j] were synthesized from adipic acid dihydrazide and different aromatic acids in the presence of phosphours oxychloide. There compounds were characterized by their IR, microanalysis, and mass spectral data.    In vitro antimicrobial were synthesized. In vitro antimicrobial activity of these compounds against (Gram negative) and (Gram positive) were reported, some of these compounds prepared derivatives exhibited antimicrobial activity

Condensation of 4-methoxybenzoyl hydrazine with 4- aminobenzoic acid in the presence of POCl3 gave the oxadiazole derivative [III] .This compound was demethylated with aluminium chloride to give series of 2- (4-hydroxy phenyl)-5-(4-amino phenyl)
1,3,4-oxadiazole [IV]. Series of Schiff s bases [V]n were synthesized by the condensation of compound [IV] with 4-n-alkoxy benzaldehyde in the presence of glacial acetic acid. Condensation of compounds [VI]n.  with adipoyl chloride in dry pyridine leads to the formation of a new homologous series [VI]n. The structures of the synthesized compounds were confirmed by physical and spectral means The new compounds [VI]n have been screened for their antibacterial activities . The results

  We described herein the synthesized and characterized of new bent and liner core compounds containing thiazolidin-4-one ring[XI-XIII] and [XIV-XVI] respectively. These compounds synthesized by sequence reactions starting from reaction resorcinol or hydroquinone with chloracetyl chloride to yield compounds [I] and [II] ,then the later compounds reactant with 4-hydroxybenzylaldehyde to product dialdehyde compounds [III] and [IV] .The Schiff bases compounds[V-VII] and [VIII-X] synthesized from reaction the compound [III] or [IV] with different aromatic  amines, while the bent and liner core mesogens containing thiazolidin-4-one ring [XI-XIII] and [XIV-XVI] synthesized from reaction Schiff bases compounds[V-VII] or  [VIII-X]

N- Benzylidene m-nitrobenzeneamines     ( Schiff     bases )  were

prepared by condensation of m-nitroaniline with aromatic aldehydes . These Schiff bases were  found to react with maleic anhydride to give

2-Aryl-3-( m-nitrophenyl )-2,3- dihydro ( 1,3] oxazepine -4,7-diones and with phthalic anhydride to give 2-Aryl-3-( m- nitrophenyl) -2,3

- dihydrobenz [ 1,2-e  ) [ 1,3]  oxazepine -4,7-  diones whicb  were

reacted with pyrrolidine to give the anilide - pyrrolidides  of maleic acid and phthalic acid.