Synthesis, Characterisation and UV-Vis Properties of Azocalix[4]crowns

This article describes the synthesis, structure andUV properties of azocalixcrowns in which the photoresponsivetrans-cis azo benzene unit has been introduced in the glycolicchains of the calix[4]crowns. The synthesis proceeded via the selective-1,3O-dialkylation of calix[4]arene with glycolic chains terminated bynitrophenyl residues. After reduction of thenitro groups into amino functions,intramolecular oxidative coupling produced thecapping of the calixarene. Thesynthetic approaches and the cis-transstructure of these new ligandsare discussed and full details on synthesesand structural data are given. Apreliminary example of cesium complexation byone of the ligands is proposed.     

Synthesis and properties of substituted 2-methylene-hydrazono-2,3-dihydro-3-benzo[<Emphasis Type="Italic">b</Emphasis>]furanones

The reaction of 2,3-dihydro-2,3-benzo[b]furandione with the triphenylphosphazines of diazo compounds leads to substituted 2-methylenehydrazono-2,3-dihydro-3-benzo[b]furanones, which are hydrolyzed in an acidic medium to the substituted methylenehydrazides of o-hydroxyphenylglyoxalic acid and react with amines to form the products of addition at the activated CH=N bond of the side chain or 2-hydrazono-2,3-dihydro-3-benzo[b]furanone respectively. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 817–822, June, 2007.     

Comparative study on the synthesis, photoluminescence and application in InGaN-based light-emitting diodes of TAG:Ce phosphors

Cerium-doped terbium aluminum garnet phosphors, Tb₃Al₅O₁₂:Ce³⁺ (TAG:Ce³⁺), were prepared with different methods: co-precipitation (CP), half dry-half wet (HDHW), sol-combustion (SC) and Pechini method plus conventional solid state reaction (SS) method. Comparative study on the phase-formation, particle size, morphologies and luminescent characteristics of the phosphors synthesized with different methods was carried out by means of XRD, FE-SEM and photoluminescence (PL) analysis and SC method was confirmed by the comparison of the results to be an easy and an effective process for preparing efficient and nano-sized Tb₃Al₅O₁₂:Ce³⁺ phosphors. Various factors influencing particle size, morphology and PL of the phosphors, such as precursor preparation, reaction temperature and heating time, were also investigated. Light-emitting diodes (LEDs) were fabricated with each phosphor and a ∼460 nm emitting InGaN chip. The LEDs from SS, HDHW and CP exhibit strong white emission while those from SC and Pechini emit yellow, revealing that the emission characteristics of LEDs are influenced not only by the morphology and the particle size of the phosphors, but also by the preparing process of the phosphors.     

Reactions of Cyanomethanesulfonamides with Aldehydes and Synthesis of 2-Benzyl-2,3-dihydrobenzopyrano[3,2-e] [1,2,4]thiadiazine 1,1-Dioxides

Summary.  Reactions of cyanomethanesulfonamides with aromatic aldehydes in the presence of AcOH and piperidine produced the addition products, the 1-cyano-2-arylethenesulfonamides, whereas reactions with benzonitrile yielded the 2-amino-1-cyano-2-phenylethenesulfonamides only when done in THF with BuLi. No addition products were isolated from the analogue reactions with 2-hydroxybenzaldehyde (salicylaldehyde). Instead, we obtained 2-imino-2H-chromene-3-sulfonamides with good to excellent yields. These 2H-chromene derivatives allowed a number of transformations, from which the reactions with orthoformates opened an approach to the hitherto unknown benzopyrano[3,2-e] [1,2,4]thiadiazine ring system.     

2,2,4-Trimethylhydroquinolines in the Bischler-Melau Reaction

8-R-1-Aryl-4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]quinolines have been synthesized by the Bischler-Melau reaction in the series of 6-R-2,2,4-trimethylhydroquinolines.     

Reaction of vinyloxyalkylamines with mercaptoacetic acid

N-[2(3)-Hydroxyalkylj-4-thiazolidinones have been synthesized by the reaction of 2(3)-vinyloxyalkylamines with mercaptoacetic acid in 24–69 % yield. The structure of the compounds obtained was supported by (R and¹H NMR spectroscopic data.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 677–679, March, 1996.     

Reaction of 1,2-diarylhydrazines with acetic anhydride catalyzed by 4-(dimethylamino)pyridine

Summary A new method for the synthesis of 1,2-diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-ones3 and 4-acetyl-1,2-diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-ones5 is presented. The reaction of 4,4-disubstituted 1,2-diarylhydrazines1 with acetic anhydride in the presence of an equimolar amount of 4-(dimethylamino)pyridine leads to mixtures of the corresponding acetyl derivatives2 and3. Under the same conditions, 2,2-disubstituted 1,2-diarylhydrazines yield mixtures of3 and5.

---

4-(Dimethylamino)pyridin-katalysierte Reaktion von 1,2-Diarylhydrazinen mit Essigsäureanhydrid

Zusammenfassung Eine neue Methode zur Synthese von 1,2-Diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-onen3 und 4-Acetyl-1,2-diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-onen5 wird beschrieben. Die Reaktion von 4,4-disubstituierten 1,2-Diaryl-hydrazinen1 mit Essigsäureanhydrid führt in Gegenwart eines Äquivalentes 4-(Dimethylamino)pyridin zu Gemischen der entsprechenden Acetylderivate2 und3. Unter den gleichen Bedingungen werden aus 2,2-disubstituierten 1,2-Diarylhydrazinen Gemische aus3 und5 erhalten.

     

N-茄呢基胺类糖酯化合物的合成及生理活性

在氢氧化钠和四丁基溴化铵存在下,将化合物2-N-茄呢基胺基苯甲酸(3)和N-茄呢基己二酰胺酸(6)分别与O-乙酰基溴代葡萄糖、O-乙酰基溴代半乳糖、O-乙酰基溴代乳糖和O-乙酰基溴代麦芽糖反应制得对应的糖酯4a～4d和7a～7d,由元素分析,IR,1H NMR和MS确证了8个新化合物的结构,并对其中6个化合物(4a,4d和7a～7d)在三种癌细胞模型上进行了一些初步体外生理活性的测试.     

Synthesis, structure and magnetic properties of the S=1/2, one-dimensional antiferromagnet, Y5Re2O12

Single crystals of Y₅Re₂O₁₂ have been grown, and the crystal structure has been determined by X-ray diffraction. This compound crystallizes in space group C2/m with cell dimensions of a=12.4081(10) Å b=5.6604(5)Å, c=7.4951(6) Å, β=107.837(3)°, Z=2. The final refinement led to R1=0.0238, WR2=0.0459 for 1053 observed reflections with F>4σ(F₀). Edge-sharing ReO₆ octahedra form infinite linear [ReO₂O_4/2]_n chains along the b direction with alternating short and long Re-Re distances. Three crystallographically independent yttrium atoms surround O2 to form OY₄ tetrahedra, which share edges and corners in the ab plane to form a two-dimensional Y₅O₄ network which separates the [ReO₂O_4/2]_n magnetic chains. This compound is therefore isostructural with the series Ln₅Re₂O₁₂Ln=Gd-Lu, which have been known since 1969. The average Re oxidation state is +4.5 in the chains and a reasonable, if qualitative MO scheme results in one unpaired electron per Re dimer. Consistent with this, magnetic susceptibility data can be fitted to the one-dimensional antiferromagnetic Heisenberg model with S=1/2 and parameters J^intra/k=−89(1)K, g=2.15(4) and χ(TIP)=5(1)×10⁻⁴ emu/mol. There is no sign of long-range magnetic order down to 2 K. These results are contrasted with those for the isostructural Y₅Mo₂O₁₂.     

Microwave synthesis,characterization and catalytic properties of titanium-incorporated ZSM-5 zeolite

Titanium-incorporated ZSM-5 zeolites (Si/Al = 50–200 and Si/Ti = 70) were successfully synthesized in a one-step sol-gel process under microwave irradiation. The characteristics of Ti-ZSM-5 zeolites were investigated using X-ray power diffraction, UV/Vis-DRS, FT-IR spectroscopy and solid-state ²⁷Al-NMR to monitor the physico-chemical properties. Simultaneously, the acidic properties were characterized by the NH₃-TPD profile. The characterization results revealed that the Ti⁴⁺ and Al³⁺ ions were well incorporated into the framework of Ti-ZSM-5 zeolite. The prepared zeolite was moderately active but selective in the dehydration of methanol to dimethyl ether.