Synthesis and Crystal Structure of N-(2-(1,3,4-oxadiazol-2-yl)phenyl)-2,3-dimethylaniline

The title compound, N-（2-（1,3,4-oxadiazol-2-yl）phenyl）-2,3-dimethylaniline, was synthesized and studied by single-crystal X-ray diffraction method. The structure of the product was confirmed by IR, ^1H- and ^13C-NMR spectroscopy, elemental analysis and mass spectrometry. These experimental studies were supported by theoretical optimizations.

Synthesis of 5,7-Dimethyl-2-(5-Substituted-1,3,4-Oxadiazole-2-yl)- Methylenethio-1,2,4-Triazolo[1,5-a]Pyrimidines as Potential Fungicides

A series of diheterocyclic compounds containing 1,2,4-triazolo [1,5-a]pyrimidine and 1, 3,4-oxadiazole were designed and synthesized starting from 2-mercapto-5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine. The structure of all compounds prepared were confirmed by H-1 NMR spectroscopy and elemental analysis. The preliminary bioassay indicated that the title compounds displayed good fungicidal activity against Rhizoctonia solani.

Syntheses, Crystal Structures, and Biological Activities of Two 5-Pyrimidinyl-1,2,4-oxadiazoles

Two 5-pyrimidinyl-1,2,4-oxadiazoles were synthesized through two different routes and their structures were characterized by single-crystal X-ray diffraction, NMR and MS. Compound 3, 5-（2-chloro-4-methyl-6-phenylpyrimidin-5-yl）-3-phenyl-1,2,4-oxadiazole, crystallizes in orthorhombic, space group Pbca with a = 19.1575（11）, b = 8.2115（5）, c = 21.2035（12）A, V = 3335.6（3）A3 and Z = 4. Compound 6, 5-（2,6-dichloropyrimidin-4-yl）-3-phenyl-1,2,4-oxadiazole, crystallizes in monoclinic space group Pn with a = 8.4275（13）, b = 5.4088（8）, c = 13.493（2）A, β = 99.768（3）°, V = 4658.6（6）A3 and Z = 8. Preliminary bioassay indicated that the two title compounds had good herbicidal activities.

An expeditious and one-pot synthesis of unsymmetrical 2,5-disubstituted-1,3,4-oxadiazoles under microwave irradiation and solvent-free conditions

A one-pot synthesis of some unsymmetrical 2,5-disubstituted-1,3,4-oxadiazoles via cyclocondensation of benzoylhydrazines with orthoesters under solvent-free and microwave conditions are described here. The reaction is efficiently catalyzed by silica- supported sulfuric acid as it provided the title compounds in high yields and relatively short times. The catalyst is reusable and can be applied several times without considerable decrease in the yields and rates of the reactions.

Recent advances on the nitrogen-rich 1,2,4-oxadiazole-azoles-based energetic materials

This review covers recent advances in the synthesis and energetic performance of nitrogen-rich 1,2,4-oxadiazole-azoles-based energetic materials.These materials comprise of 1,2,4-oxadiazole subunit as a key structural motif linked to different nitrogen-rich or nitrogen-oxygen azoles:tetrazole,furazan,furoxan,1,3,4-oxadiazole,pyrazole,and triazole.Particular attention is devoted to the introduction of various energetic groups including nitro,nitramino,azo,azoxy,dinitromethyl,trinitroethyl moieties,and their combination.The physicochemical and available performance parameters including density,decomposition temperature,heat of formation,detonation pressure,detonation velocity,impact sensitivity,and friction sensitivity of typical energetic compounds are also provided and analyzed.Eventually,it was obtained that several screened compounds exhibit superior detonation properties and outstanding insensitivities,which can be classified as a new family of high-performance energetic materials.Additionally,1,2,4-oxadiazole-azoles-based energetic materials still have many thorough works to further exploited and studied,expecting to get very promising insensitive high explosives for practical application and industrialization.

Synthesis of 5-Substituted-3-[(2’R,4’R)-4’-Hydroxy-2’-hydroxymethyltetrahydrofuran-4’-yl]-1,2,4-oxadiazoles and Their Epimers

The syntheses of 5-substituted-3-[( 2’ R, 4’ R)-4 ’ -hydroxy-2 ’ -hydroxymethyltetra-hydrofuran-4’ -yl]D-1 ,2, 4-oxadiazoles and their epimers were accomplished with the aid of th construction of 1,2, 4-oxadiazoles by condensation of O-acylated cyanohydrins with hydroxylamine via intramolecular transacylation and subsequent cyclization.

SYNTHESIS OF DERIVATIVES OF 3-β-D-XYLOPYRANOSYL-1,2,4-OXADIAZOLES

The synthesis of derivatives of 3-β-D-xylopyranosyl-1,2,4-oxadiazoles is accomplished by condensing protected β-D-xylopyranosyl amidoxime with acid anhydrides or various substituted benzoyl chlorides in good yield.The structures of now derivatives were identified by spectra and elemental analysis. The stability of 1,2,4-oxadiazole ring and mechanism of cyclization were. investigated.

Preparation of 3-Aryl-5-phenylselenomethyl 1, 2, 4-Oxadiazole and their Further Deselenenylation Reaction

A mild Porco’s two-step, one-pot condensation reaction for the preparation of 3-aryl- 5-phenylselenomethyl 1, 2, 4-oxadiazole through phenylseleno acetic acid and benzamidoxime was reported. And further deselenenylation of 3-aryl-5-phenylselenomethyl 1, 2, 4-oxadiazole was studied.

Synthesis, Crystal Structure and Antitumor Activity of 4-(5-(2,6-Difluorophenyl)-1,3,4-oxadiazol-2-ylthio)-2-(trifluoromethyl)thieno[2,3-d]pyrimidine

The title compound 4-(5-(2,6-difluorophenyl)-1,3,4-oxadiazol-2-ylthio)-2-(trifluoromethyl)thieno[2,3-d]pyrimidine(C15H5F5N4OS2, Mr = 416.35) was designed and synthesized as antitumor agent, and its structure was determined by 1H NMR, 13C NMR, MS, elemental analysis and single-crystal X-ray diffraction. The crystal belongs to monoclinic system, space group P21/c with a = 9.904(2), b = 10.057(2), c = 16.595(3) ?, β = 100.000(3)°, V = 1627.9(6) ?3, Z = 4, F(000) = 832, Dc = 1.699 g/cm3, μ = 0.395 mm-1, R = 0.0468 and wR = 0.1255 for 4726 independent reflections(Rint = 0.0336) and 2847 observed ones(I > 2σ(I)). The in vitro antitumor activity of the title compound was preliminarily evaluated by the standard MTT assay.

Photoluminescence and Electroluminescence Properties of 2,5-Bis[2,2′-bis(5-phenyl)-1,3,4-oxadiazole] Thiophene(T-OXD) and T-OXD/Poly(9-vinylcarbazole) Blends

The photoluminescence(PL) and the electroluminescence(EL) properties of a novel organic compound, 2,5-bis(2,2′-bis(5-phenyl)-1,3,4-oxadiazole(T-OXD), were studied in chloroform and in a solid thin film. The PL and the EL properties of T-OXD/poly(9-vinylcarbazole)(PVK) blends were also studied, which contained various contents of T-OXD. The PL maximum emission peaks of T-OXD/PVK blends show gradual bathochromtic-shift with the increase of the T-OXD content. The EL spectra of T-OXD/PVK devices are similar to their PL spectra, and all the EL maximum emission peaks show bathochromtic-shift compared with the corresponding PL spectra, which is ascribed to the formation of electroplex. The turn-on voltages for ITO/T-OXD:PVK/Al devices decreased from 13.5 V of the device cotaining 0.1% T-OXD(mass fraction) to 5 V of the device containing 5% T-OXD, which suggests that T-OXD improves the energy level match between T-OXD and PVK and enhances the emission efficiency. The experimental results indicate that T-OXD can be used as a good electron transporting material.

NEW HETEROCYCLIC SYSTEMATIC SYNTHESIS V.THE SYNTHESIS AND CHARACTERISTICS OF 1,3a,5-TRISUBSTITUTED-3a,4,5,11-TETRAHYDRO-1,2,4-OXADIAZOLINO[5,4-d][1,5]BENZODIHETEROPINES

Twenty-seven oxadiazolino[5,4-d][1,5]benzodiheteropine derivatives have been synthesized by the 1,3-dipolar cycloaddition of benzodiheteropines with nitrile oxide 1,3-dipoles,their conformations and the characteristics of the newly formed oxadiazoline fused on them have been studied.It has also been found that the mass spectra show characteristic fragmentation patterns.

微波促进下3-(2-苯并呋喃基)-4-氨基-5-巯基-1,2,4-三唑及其衍生物的合成

微波辐射条件下,首先由2-苯并呋喃甲酰肼依次与二硫化碳和水合肼反应合成3-(2-苯并呋喃基)-4-氨基-5-巯基-1,2,4-三唑,进一步在微波辐射条件下由4-氨基-5-巯基-1,2,4-三唑分别与芳甲酸/芳氧基乙酸、α-溴代苯乙酮及芳醛反应以较高产率制得了相应的1,2,4-三唑并[3,4-b]-1,3,4-噻二唑、1,2,4-三唑并[3,4-b]-1,3,4-噻二嗪及4-芳亚甲基亚胺基-5-巯基-1,2,4-三唑.产物结构经IR,1HNMR,MS及元素分析进行了表征.

One-pot synthesis,antibacterial and antifungal activities of novel 2,5-disubstituted-1,3,4-oxadiazoles

A series of novel 2,5-disubstituted-1,3,4-oxadiazoles have been synthesized from long-chain alkanoic and alkenoic acids. The structures of these compounds have been elucidated by elemental and spectral （IR, ^1H NMR, ^13C NMR, MS） analysis. Furthermore, compounds were screened for in vitro antibacterial activity against the representative panel of two Gram-positive and two Gram- negative bacteria. All the synthesized compounds were also tested for their inhibitory action against five strains of fungus. The various compounds show potent inhibitory action against test organisms. 2007 Abdul Rauf. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

A mild and facile method for one pot synthesis of 2,5-di-substituted 1,3,4-oxadiazoles at room temperature

2,5-Di-substituted 1,3,4-oxadiazoles 3a-n have been synthesized as a one pot procedure from the reaction of acid hydrazide 1, acyl halides 2 and phosphorus pentoxide in acetonitrile at room temperature. High yield, short reaction time （10-15 min）, mild condition, and easy work-up are advantages of this methodology.

Synthesis and Fungicidal Activities of 2-Alkylthio-5-(3,4,5-tribenzyloxyphenyl)-1,3,4-oxadiazoles

Abstract： Ten novel 2-alkylthio-5-（3, 4, 5-tribenzyloxyphenyl）-1, 3, 4-oxadiazole derivatives （5a-j） were synthesized from methyl 3, 4, 5-trihydroxybenzoate by ethedfication, hydrazidation, cyclization and thioetherification reactions. The structures of 5a-j were confirmed by 1HNMR, MS spectra and elemental analysis. The results indicated that most of the compounds 5 exhibited good fungicidal activities. The activity of 5h is higher than 90% against Fusarium oxysporum and Botrytis cinereapers in 50 mg/L.

Synthesis and Photoluminescence of a Novel Iridium Complex (BuPhOXD)_2Ir(acac) with Unit of 1, 3, 4-Oxadiazole

A novel cyclometalated iridium complex with 1, 3, 4-oxadiazole moiety was synthesizedand characterized. Its UV and photoluminescent properties were studied. The strong UVabsorption intensity around 462 nm attributed to spin-forbidden triplet metal–ligand charge transferband and photoluminescence at 518 nm were observed. This indicated that achieved iridiumcomplex could be used as an efficient electrophosphorescent material.

Synthesis,Crystal Structure and Biological Activity of 2-(Anthracen-9-yl)-5-p-tolyl-1,3,4-oxadiazole

A novel compound,2-（anthracen-9-yl）-5-p-tolyl-1,3,4-oxadiazole（C23H16N2O）,has been synthesized by the condensation of 4-methylbenzohydrazide and anthracene-9-carbaldehyde in an ethanol solution with chloramine-T.The compound was characterized by 1H-NMR,13C-NMR,MS and single-crystal X-ray diffraction.The crystal belongs to the triclinic system,space group P with a = 7.7817（4）,b = 8.8544（5）,c = 12.4726（8） ,β = 92.8520（10）°,Z = 2,V = 826.58（8） 3,Dc = 1.352 g/cm3,Mr = 336.38,λ（MoKα） = 0.71073 ,μ = 0.084 mm-1,F（000） = 352,R = 0.0381 and wR = 0.1099.The dihedral angle between anthracene skeleton and phenyl ring is 64.19°.A total of 6354 unique reflections were collected,of which 3172 with I 〉 2σ（I） were observed.X-ray analysis indicated an offset face-to-face π-π stacking interaction between anthracene skeletons and an offset face-to-face π-π stacking interaction between phenyl ring planes.The novel compound molecules are connected through the offset face-to-face π-π stacking interactions to generate a three-dimensional network.The preliminary bioassay results showed that the novel compound exhibited significant insect growth inhibitory activity against Spodoptera litura Fabricius larvae.

Solvent-free synthesis of some new 2-(3,5-dimethoxy-4-methylphenyl)-5-aryl-1,3,4-oxadiazoles

An expeditious microwave-accelerated one-step synthesis of some new 2-（3,5-dimethoxy-4-methylphenyl）-5-aryl-1,3,4- oxadiazoles by reaction of 3,5-dimethoxy-4-methyl hydrazide with different carboxylic acids in presence of thionyl chloride under neat conditions,has been achieved.

Syntheses and Crystal Structures of Two New Complexes Generated from 2-（（Pyridin-3-ylmethyl）thio）-5-（6-quinolinyl）-1,3,4-oxadiazole and Ag~Ⅰ Salts

Two new Ag~Ⅰ-complexes have been synthesized based on the semi-rigid ligand 2-（（pyridin-3-ylmethyl）thio）-5-（6-quinolinyl）-1,3,4-oxadiazole（L）,obtained by the condensation reaction of 5-（6-quinolinyl）-1,3,4-oxadiazole-2-thiol and 3-chloromethyl pyridine hydrochloride. Crystallization of L with Ag OTf and Ag PF_6 in a CH_2Cl_2/MeO H mixed solvent system at room temperature affords a novel supramolecular [Ag_2L_2（CF_3SO_3）_2]（I） and a coordination polymer [Ag L（PF_6）]_n（Ⅱ）,respectively. Two complexes were characterized by TGA,X-ray powder and single-crystal diffraction.

Synthesis, Crystal Structure and Theoretical Calculations of N-Benzyl-1-(5-(3-chlorophenyl)-1,3,4-oxadiazol-2-yl)cyclopentanamine

N-benzyl-1-（5-（3-chlorophenyl）-1,3,4-oxadiazol-2-yl）cyclopentanamine was synthesized via one-pot reaction of appropriate benzylamine, cyclopentanone,（N-isocyanimino）triphenylphosphorane and m-chlorobenzoic acid. The quantum theoretical calculations for crystal structure were performed by density functional theory（DFT/B3LYP/6-311＋G＊）. From the optimized structure, geometric parameters were obtained and experimental measurements were compared with the calculated data. Frontier molecular orbitals（FMOs）, total density of states（DOS）, molecular electrostatic potential（MEP）, molecular properties, natural charges, NMR parameters and NBO analysis for the product were investigated by theoretical calculations.