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

New challenging problems in plant protection technology have promoted research to discover more efficient pesticides. In recent years, many chemists have paid much attention to compounds bearing 1,2,4-triazolo [1,5-a] pyrimidine rings due to their broad spectrum of biological activities such as herbicidal and fungicidal effects1-7. Up to now, a great variety of these kinds of compounds have been synthesized, among which some commercially herbicides have been developed including metosulam, f…     

Studies on Acylthiosemicarbazides and Related Heterocycle（XXIII）──Synthesis and Bactericidal Activity of 5－（5－（3－pyridyl）－2H－tetrazole－2－ylmethyl）－2－arylamino－1，3，4－oxadia－zoles

ＳｔｕｄｉｅｓｏｎＡｃｙｌｔｈｉｏｓｅｍｉｃａｒｂａｚｉｄｅｓａｎｄＲｅｌａｔｅｄＨｅｔｅｒｏｃｙｃｌｅ（ＸＸＩＩＩ）──ＳｙｎｔｈｅｓｉｓａｎｄＢａｃｔｅｒｉｃｉｄａｌＡｃｔｉｖｉｔｙＯｆ５－（５－（３－ｐｙｒｉｄｙｌ）－２Ｈ－ｔｅｔｒａｚｏｌｅ－...     

含1,3,4-噁二唑环PPV齐聚物的合成及发光特性研究

含有1,3,4-噁二唑结构单元的PPV齐聚物是一类具有良好电子传输功能的发光材料。通过Wittig—Homer反应合成了2,5-二{4-[2-(取代苯基)乙烯基]苯基}-1,3,4-噁二唑(1)。1的化学结构经元素分析和光谱分析确认,其分析数据表明1分子结构中的C=C双键均为反式结构。苯环上的取代基对1的UV—Vis吸收光谱和PL荧光光谱有显著影响。     

5-Nitrotetrazol and 1,2,4-Oxadiazole Methylene-Bridged Energetic Compounds: Synthesis,Crystal Structures and Performances

A new structural type for melt cast materials was designed by linking nitrotetrazole ring with 1,2,4-oxadiazole through a N-CH₂-C bridge for the first time. Three N-CH₂-C linkage bridged energetic compounds, including 3-((5-nitro-2H-tetrazol-2-yl) methyl)-1,2,4-oxadiazole (NTOM), 3-((5-nitro-2H-tetrazol-2-yl)methyl)-5-(trifluoromethyl)-1,2,4 -oxadiazole (NTOF) and 3-((5-nitro-2H-tetrazol-2-yl)methyl)-5-amine-1,2,4-oxadiazole (NTOA), were designed and synthesized through a two-step reaction by using 2-(5-nitro-2H-tetrazole -2-yl)acetonitrile as the starting material. The synthesized compounds were fully characterized by NMR (¹H, ¹³C), IR spectroscopy and elemental analysis. The single crystals of NTOM, NTOF and NTOA were successfully obtained and investigated by single-crystal X-ray diffraction. The thermal stabilities of these compounds were evaluated by DSC-TG measurements, and their apparent activation energies were calculated by Kissinger and Ozawa methods. The crystal densities of the three compounds were between 1.66 g/cm³ (NTOA) and 1.87 g/cm³ (NTOF). The impact and friction sensitivities were measured by standard BAM fall-hammer techniques, and their detonation performances were computed using the EXPLO 5 (v. 6.04) program. The detonation velocities of the three compounds are between 7271 m/s (NTOF) and 7909 m/s (NTOM). The impact sensitivities are >40 J, and the friction sensitivities are >360 N. NTOM, NTOF and NTOA are thermally stable, with decomposition points > 240 °C. The melting points of NTOM and NTOF are 82.6 °C and 71.7 °C, respectively. Hence, they possess potential to be used as melt cast materials with good thermal stabilities and better detonation performances than TNT.     

蓝色有机电致发光材料OXD-7的合成及性能

重点研究了蓝色有机电致发光材料OXD-7的合成路线及提高产率的方法,并用自行设计加工的升华提纯装置进行两次OXD-7的升华提纯,可使产物纯度达到99.2%。通过真空镀膜制作出结构为ITO/CuPc/NPB/OXD-7/Alq₃/Mg-Ag/Al的器件,器件采用透明ITO导电玻璃作正极,依次真空蒸镀酞菁铜、NPB、OXD-7、Alq₃、Mg-Ag电极,最后在合金电极上覆盖一层很薄Al膜。膜厚由频率震荡计监测,测试了器件的光电性能以及寿命,研究并讨论了材料的纯度对器件寿命的影响。     

S<Subscript>(2)</Subscript>- or N<Subscript>(3)</Subscript>-Substituted 2-Mercapto-5-(4-pyridyl)-1,3,4-oxadiazoles

New S₍₂₎- or N₍₃₎-substituted 2-mercapto-5-(4-pyridyl)-1,3,4-oxadiazoles have been obtained and characterized. The direction of substitution depends on the structure of the initial reactants and the reaction conditions. The synthesis of several thiosemicarbazides has been effected from isonicotinic acid hydrazide.     

Synthesis of (R) and (S) enantiomers of Fmoc-protected 1,2,4-oxadiazole-containing β-amino acids from Fmoc-(R)-β-HAsp(OtBu)-OH

Fmoc-(R)-β-HomoAsp(OtBu)-OH was used for the synthesis of both (R) and (S) enantiomers of various Fmoc-protected 3-substituted 1,2,4-oxadiazole-containing β³-amino acids. The 1,2,4-oxadiazole heterocycle was formed using sodium acetate, a Fmoc-compatible and efficient catalyst for cyclodehydration.     

Characterization of a new non-centrosymmetric polymorph of diphenyl-1,3,4-oxadiazole

Diphenyl-1,3,4-oxadiazole (DPO) crystallization experiments from solutions clearly reveal the polymorphism of the substance. Besides the formerly known centrosymmetric monoclinic structure with space group P2₁/c (DPO I) a new monoclinic structure with the non-centrosymmetric space group Cc is found (DPO II): a=2.4134(4) nm, b=2.4099(3)  nm, c=1.2879(2) nm, β=110.048(3)°, and V=7.0363(17) nm³. The asymmetric unit contains six independent molecules in a complex packing motif. A re-determination of the crystal structure of DPO I at room temperature gives lattice parameters a=0.51885(6) nm, b=1.8078(2) nm, c=1.21435(14) nm, β=93.193(3)°, and V=1.1373(2) nm³. X-ray measurements at 363 K show a significant increase of the unit cell volume by 1.6%. Differences between both structures concerning morphology and characteristic Raman bands are outlined in detail. DSC investigations show an irreversible transition from DPO I to DPO II at 97 °C. DPO II does not show any transition in the temperature range up to the melting point at 141 °C. The non-centrosymmetric DPO II structure shows triboluminescence.     

2’-芳基-3-（1，4，5，6-四氢-6-哒嗪酮-3-羰基）氨基硫脲及其环化产物的合成

以α-酮戊二酸为起始原料，合成了1，4，5，6-四氢．6-哒嗪酮-3-甲酰肼(2)，然后将2与异硫氰酸芳基酯反应得到相应的芳基氨基硫脲衍生物3a～3f．用硫酸、醋酸汞或氢氧化钠分别将芳基氨基硫脲环化得到一系列新的1，3，4-噻二唑、1，3，4-噁二唑和1，2，4-三唑的衍生物．化合物的结构经元素分析，IR，^1HNMR和MS谱得以证实．     

含噁二唑杂环取代的新型三唑并嘧啶衍生物的合成及其生物活性

2-肼羰基亚甲硫基-5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶与二硫化碳在乙醇溶液中回流制得化合物2-(5-巯基-1,3,4-噁二唑-2-亚甲硫基)-5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶, 后者在碱性环境中与卤化苄反应得到17种新型双杂环化合物. 对所得化合物结构均经元素分析, ¹H NMR和MS确认. 初步生物活性测试表明这些化合物具有一定的杀菌活性.