Syntheses of Chiral Fused Heterocyclic Compounds Containing l,2,4-Triazole Ring

The chemistry of life is based considerably on chirality. Consequently, stereospecificity has to be regarded as an especially important characteristic of biological systems. The influence of stereospecificity of the biological activities of enzyme inhibitors or compounds binding to receptor is a well known fact in the field of drug action^[1]. s-Triazoles and l,3,4-thiadiazoles are reported to exhibit broad spectrum of biological and pesticidal activities^[2-3].In recent years, bridge head nitrogen heterocycles have received much attention as anthelmintic agents, however, it is not observed that the syntheses of chiral fused heterocyclic compounds containing s-triazoles and l,3,4-thiadiazoles. In order to study the relationship between stereochemistry and the performance of fungicides, we have synthesized a series of (s)-1,2-di(3-aryl-s-triazolo[3,4-b][1,3,4] thiadiazolo-6-yl) ethylamine and (s)-1-(3-aryl-s-triazolo[3,4-b][l,3,4] thiadiazolo-6-yl) ethylamine by the condensation of 3-aryl-4-amino-5-mercapto-1,2,4-triazoles with L-aspartic acid and L-alanine in the presence of phosphorusoxychloride.     

Diastereoisomeric Separation of (R,S)-l,l'-Binaphthalene-2,2'-Diol-Mono-[(-)-Menthyl] Carbonate by RP-HPLC

(R)-l,l'-binaphthalene-2,2'-diol-mono-[(-)-menthyl] carbonate (1) and (S)-l,l'-binaphthalene-2,2'-diol-mono-[(-)-menthyl] carbonate (2) are two new compounds synthesized from racemic binaphthol by diastereoselective crystalization after derivatization with (-)-menthyl chloroformate. Reduction of these monoesters would afford pure enantiomers of binaphthol, which are important C₂-symmetrical compouds for asymmetric catalysis and the starting material for many other important chiral binaphthyl compounds.     

手性二环[3.3.0]辛-3-烯类化合物的合成

研究了5-(1-孟氧基)-3-溴-2(5H)-呋喃酮新手性源(1)与某些碳亲核试剂发生的串联不对称Michael加成/分子内亲核取代反应,反应中生成2个新的手性中心得到一般方法难以合成的光学纳二环[3.3.0]辛-3-烯类化合物.通过[α]、IR、UV、¹HNMR、¹³CNMR、MS、元素分析以及X射线四圆衍射等方法确定了手性二环[3.3.0]辛-3-稀类化合物化学结构和绝对构型.     

Novel and Efficient Resolution of 1,1'-Bi-2-naphthol and Synthesis of Optically Pure Unsymmetrically Substituted Binaphthyls

Both enantiomers of 1, 1'-Bi-2-naphthol (BINOL) 1 are important chiral ligands and auxiliaries for a number of asymmetric transformations such as aldol condensations, alkylations, Diels-Alder reactions, Michael additions, epoxidations, etc. Optically pure 1 and their derivatives have also been used extensively in chiral recognition, chiral separation and construction of functionalised materials^[1]. As a result the development of efficient and economic methods for the preparation of optically pure 1 has attracted much attention in recent years^[2] and novel methods for the resolution of racemic 1 (Rac-1) continue to be developed.     

The Williamson Reaction: A New and Efficient Method for the Alternate Resolution of 2,2'-Bis(bromomethyl)-1,1'-binaphthyl and 1,1'-Binaphthalene-2,2'-diol

Treatment of 2,2'-bis(bromomethyl)-1,1'-binaphthyl [(R,S)-2] with 1,1'-binaphthalene-2,2'-diol (+)-(R)-1 and cesium or potassium carbonate in refluxing acetone, gave the diastereoisomeric dioxacyclophanes (-)-(R,S)-3a and (+)-(R,R)-3b, both obtained in high yield, and the cyclic tetraether (+)-(R,R,R,S)-4 as isolated side product. Boron tribomide-promoted ether cleavage of 3a and 3b gave optically pure (-)-(S)-2 and (+)-(R)-2, respectively, and the recovered diol (+)-(R)-1. Alternatively, the same reaction sequence furnished the resolved diols (-)-(S)-1 and (+)-(R)-1 from (R,S)-1 and (+)-(R)-2, as well as optically pure 2,2'-bis(chloromethyl)-1,1'-binaphthyl (+)-(R)-5 from the racemic dibromide (R,S)-2 by using boron trichloride for ether cleavage.     

Rational enantioselective design of chiral heterobimetallic single-chain magnets: synthesis, crystal structures and magnetic properties of oxamato-bridged M(II)Cu(II) chains (M=Mn, Co)

A new series of neutral oxamato-bridged M(II)Cu(II) chiral chains of general formula [MCuL(x)(S)(m)(H(2)O)(n)]·aS·bH(2)O [L(1)=(M)-1,1'-binaphthalene-2,2'-bis(oxamate) with M=Mn (1a) and Co (1b); L(2)=(P)-1,1'-binaphthalene-2,2'-bis(oxamate) with M=Mn (2a) and Co (2b)] and the analogous racemic chains of formula [MCuL(3)(S)(m)(H(2)O)(n)]·aS·bH(2)O [L(3)=1,1'-binaphthalene-2,2'-bis(oxamate) with M=Mn (3a) and Co (3b)] have been prepared by reaction of the corresponding dianionic oxamatocopper(II) complex [Cu(L(x))](2-) with Mn(2+) or Co(2+) cations in either dimethylformamide (DMF) or dimethyl sulfoxide (DMSO). Solid circular dichroism (CD) spectra of the bimetallic chain compounds were recorded to establish their chiral and enantiomeric nature. They exhibit maximum positive and negative Cotton effects, each pair of enantiomeric chains being non-superimposable mirror images. The crystal structures of the Mn(II)Cu(II) (1a-3a) and the Co(II)Cu(II) (1b and 2b) chain compounds were solved by single-crystal X-ray diffraction methods. Our attempts to obtain X-ray quality crystals of 3b were unsuccessful. The values of the shortest interchain Mn···Mn and Co···Co distances are indicative of a good isolation of neighbouring chains in the crystal lattice, which is caused by the bulky aromatic ligand. Although all the Mn(II)Cu(II) and Co(II)Cu(II) chains exhibit ferrimagnetic behaviour (-J(MnCu)=18.9-26.6 cm(-1) and -J(CoCu)=19.5-32.5 cm(-1)), only the enantiopure Co(II)Cu(II) chains (1b and 2b) show slow magnetic relaxation at low temperatures (T(B)=0.6-1.8 K), which is a characteristic of single-chain magnets (SCMs) and is related to the magnetic anisotropy of the high-spin Co(II) ion. Analysis of the SCM behaviour of 1b and 2b, based on Glauber's theory for an Ising one-dimensional system, shows a thermally activated mechanism for the magnetic relaxation (Arrhenius law dependence). The energy barriers (E(a)) to reverse the magnetisation direction are 8.2 (1b) and 8.1cm(-1) (2b), whereas the pre-exponential factor (τ(0)) is 1.9×10(-8) (1b) and 6.0×10(-9) s (2b). Interestingly, the racemic Co(II)Cu(II) chain analogue, 3b, showed no evidence of SCM behaviour.     

Syntheses of 3-[5-Methyl-1-(4-Methylphenyl)-1,2,3-Triazol-4-yl]-6-Substituted-s-Triazolo[3,4-b]-1,3,4-Thiadiazoles

1,2,3-Triazole derivatives have been reported as inhibiting tumor proliferation, invasion, and metastasis^[1]. The fused l,3,4-triazolo[3,4-b]-1,3,4-thiadiazoles derivatives show various biological effects such as antifungal^[2], antibacterial, hypotensive and CNS depressant activities^[3]. We have reported several 6-aryl-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiadiazoles in the previous paper^[4]. The novel 6-aryl-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[2,4-b]-1,3,4-thiadiazoles 6a-j have been synthesized by the condensation of 4-amino-5-mercapto-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazole 5 with various aromatic carboxylic acids in the presence of phosphorus oxychloride. The mercaptotriazole 5 was prepared from 4,the latter being prepared from 1 throng 2 and 3. The title compounds 6 were depicted in scheme 1. The structures of these compounds were established by elemental analysis, NMR, MS and IR techniques.     

Tris-chelate complexes with chiral ligands: In search of diastereoisomeric selectivity with remote stereogenic centres

The chiral ligands, 4,4′-bis{(1S,2R,4S)-(−)-bornyloxy}-2,2′-bipyridine, (1S,2R,4S)-1, and 4,4′-bis{(1R,2S,4R)-(+)-bornyloxy}-2,2′-bipyridine, (1R,2S,4R)-1, have been prepared and characterized by spectroscopic techniques and, for (1S,2R,4S)-1, by single crystal X-ray diffraction. Despite the use of enantiomerically pure ligands, the formation of the complexes [Fe((1S,2R,4S)-1)₃]²⁺, [Ru((1S,2R,4S)-1)₃]²⁺, [Ru((1S,2R,4S)-1)(bpy)₂]²⁺ and [Ru((1R,2S,4R)-1)(bpy)₂]²⁺ proceeds without preference for either the Δ or Λ-diastereoisomers.     

Ionothermal Synthesis and Characterization of Two Polyoxometalate-based Supramolecules

Two novel 3D supramolecular architectures with hexamolybdate and phosphotungstate anions were synthesized under ionothermal conditions. The structures were named as[Cu^I(L1)₂]₂L2[Mo₆O₁₉](1) and[Cu^I(L3)₂]_2.5· H_0.5[PW₁₂O₄₀]·H₂O(2)(L1=2,2'-bipyridine, L2=4,4'-bipyridine, L3=2,2'-biimidazole) and characterized via Fourier transform infrared spectroscopy(FTIR) and FT-Raman spectroscopy analyses. Single-crystal X-ray diffraction analysis revealed that the two compounds crystallized in the space group P and were constructed through hydrogen bonding.     

Synthesis of Heterocyclic Compounds from 2-Phenyl-l,2,3-Triazole-4-Formylhydrize

Many compounds containing the 1,3,4-oxadiazole and/or1,2,3(or 4)-triazole and thiadiazole ring system are reported to possess antibacterial^[1], antiinflammatory^[2], anticonrulsant^[3],CNS stimulant^[4] and pesticidal^[5] activities and excellent anthelmintic properties^[6,7]. In view of this and the results of the combined different nuclei system in a molecular always enhancing the therapeutic activities,the present work deals with the synthesis of the combined different pharmacologically active nuclei system mentioned above in a molecular through some new method.     

Studies on the oxidation of Cu complexes of quadridentate Schiff bases derived from salicylaldehyde or ortho-aminophenol

The oxidation of various [CuL] (where L are the dianions of quadridentate Schiff bases derived from salicylaldehyde, and 1,2-diaminoethane, namely 2,2′-[1,2-ethanediylbis(nitrilomethylidene)diphenatol], salen, its 1,3-propane homologue, saltn, or from glyoxal and ortho-aminphenol, namely 2,2′-[(ethanediimine)diphenato], glyaph, as well as some of their analogues) has been studied by cyclic voltammetry. Anodic sweeps show one, or two, usually irreversible, oxidation peaks originated by the presence of Cu^II, since neither LH₂ nor [ZnL] are oxidized under the same conditions. The oxidations of the 5-NO₂-substituted derivatives are reversible at high scan rate (1 V s⁻¹). The oxidation potentials of the complexes with substituents at the aromatic rings suggest that the electronic influence of such substituents are transmitted to the metal centre via the phenato, rather than the azomethine groups. The glyaph and saltn derivatives are oxidized at potentials higher than the corresponding salen complexes. Electronic and ESR spectroscopy studies on [CuL] samples, oxidized with a H₂O₂/H₅IO₆ mixture, suggest that the initially formed [Cu^IIIL]⁺ rapidly decomposes to Cu^II species, presumably through [Cu(II)0L ·]⁺ intermediates. Some poorly stable complexes of the formula [CuL]HSO₄·2H₂O have been isolated.     

Synthesis, Crystal Structure of Bis-terpyridinyl-calix[4]arene Derivatives and Fluorescent Sensor for Zn2+

The calix[4]arene-based podands which incorporates two terpyridinyl functional groups derived from the alkylation reactions of 4-(ω-chloroalkoxyphenyl)-2,2':6',2"-terpyridine in 1,3-alternate position at lower rim have been prepared in moderate yields. The structures of four pyridyl compounds were determined by X-ray single crystal diffraction method. The complexing properties of bis-terpyridinyl-calix[4]arenes for transition metal ions were investigated by fluorescence spectra. Bis-terpyridinyl-calix[4]arenes gave a more efficient fluorescent sensing ability to Zn²⁺.     

Sterically demanding cyclopentadienyl chemistry: synthesis of iron and zirconium complexes of 1-phenyl-3-methyl-4,5,6,7-tetrahydroindenyl

Reaction of phenyl magnesium bromide with the ,β-unsaturated ketone 3-methyl-2,3,4,5,6,7-hexahydroind-8(9)-en-1-one, followed by an aqueous work-up, generates the pro-chiral tetra-substituted cyclopentadiene, 1-phenyl-3-methyl-4,5,6,7-tetrahydroindene, Cp^‡H, a precursor to the η⁵-cyclopentadienyl ligand in (Cp^‡)₂Fe and [(Cp^‡)Fe(CO)]₂(μ-CO)₂. Both complexes were generated as mixtures of rac-(RR and SS)- and meso-(RS)-isomers, and in either case pure meso-isomer was isolated by crystallisation and characterised by single crystal X-ray structure, both molecules having crystallographic C_i symmetry. Reduction with Na/Hg cleaves meso-(RS)-[(Cp^‡)Fe(CO)]₂(μ-CO)₂ and the resulting mixture of (R)- and (S)-[(Cp^‡)Fe(CO)₂]⁻ anions reacts with MeI to give racemic (Cp^‡)Fe(CO)₂Me, which was characterised by the X-ray crystal structure. The Cp^‡ ligand is more electron donating than (η-C₅H₅) as revealed by the reduction potential of the (Cp^‡)₂Fe⁺/(Cp^‡)₂Fe couple, E°=−0.127 V (vs. Ag  AgCl). Reaction of LiCp^‡ with ZrCl₄ yields the zirconocene dichloride [Zr(Cp^‡)₂Cl₂] as mixture of rac- and meso-isomers, from which pure rac-isomer is obtained as a mixture of RR and SS crystals by recrystallisation. The reaction of rac-[Zr(Cp^‡)₂Cl₂] with LiMe gives rac-[Zr(Cp^‡)₂Me₂]. The structures of RR-[Zr(Cp^‡)₂Cl₂] and rac-[Zr(Cp^‡)₂Me₂] have been determined by X-ray diffraction. The structural studies reveal the influence of the bulky substituted cyclopentadienyl ligand on the metal---Cp^‡ distances and other metric parameters.     

Platination of [3-X-7,8-Ph2-7,8-nido-C2B9H8] (X=Et, F): Synthesis and characterisation of slipped and 1,2→1,7 isomerised products

The reaction of the labelled carborane ligand [3-Et-7,8-Ph₂-7,8-nido-C₂B₉H₈]²⁻ with a source of {Pt(PMe₂Ph)₂}²⁺ affords non-isomerised 1,2-Ph₂-3,3-(PMe₂Ph)₂-6-Et-3,1,2-closo-PtC₂B₉H₈ (1). The analogous reaction between [3-F-7,8-Ph₂-7,8-nido-C₂B₉H₈]²⁻ and {Pt(PMe₂Ph)₂}²⁺ yields 1,8-Ph₂-2,2-(PMe₂Ph)₂-4-F-2,1,8-closo-PtC₂B₉H₈ (3). Compound 1 has a heavily slipped structure (Δ 0.72 Å), which to some degree obviates the need for C atom isomerisation. However, that it is a kinetic product of the reaction is evident from the fact that it reverts to isomerised 1,8-Ph₂-2,2-(PMe₂Ph)₂-4-Et-2,1,8-closo-PtC₂B₉H₈ (2) slowly at room temperature but more rapidly with gentle warming. The heteroatom and labelled-B atom positions in the isomerised compounds 2 and 3 may be explained most simply by the rotation of a CB₂ face of an intermediate based on the structure of 1. Compounds 1–3 were characterised by a combination of spectroscopic and crystallographic techniques.     

超高效合相色谱法快速检测纺织品中的8种荧光增白剂

建立了同时检测纺织品中1,2-双(5-甲基-2-苯并恶唑基)-乙烯(PF)、7-二乙氨基-4-甲基香豆素(SWN)、2,2'-(2,5-二苯基硫代)双[5-(1,1-二甲基乙基)]苯并恶唑(OB)、2-[4-[2-[4-(2-苯并恶唑基)苯基]乙烯基]苯基]-5-甲基苯并恶唑(KSN)、1,4-双(2-氰基苯乙烯基)苯(ER-Ⅰ)、1-邻氰苯乙烯基-4-对氰苯乙烯基苯(ER-Ⅱ)、2,2-(1,4-亚萘基)双(苯并恶唑)(KCB)和4,4'-双[2-(2-甲氧基苯基)亚乙基]-1,1'-联苯(FP)8种荧光增白剂的超高效合相色谱(UPC²)检测方法。样品经二甲苯提取、浓缩、定容后,由UPC²进行定性定量分析。以超临界CO₂-甲醇为流动相,梯度洗脱,采用ACQUITY UPC² HSS C18 SB色谱柱(100 mm×3.0 mm,1.8 μm)进行分离。8种荧光增白剂在1.0~20.0 mg/L范围内线性良好(r≥0.9991),定量限(LOQ,S/N=10)在0.70~0.95 mg/L之间。不同添加水平的回收率范围为90.9%~96.5%,相对标准偏差(RSD)为2.8%~4.2%。该方法简单、准确度高、分析时间短,可用于快速检测纺织品中的8种荧光增白剂。     

Second-harmonic generation from monolayer Langmuir–Blodgett films of various push–pull pyridine and terpyridine metal complexes

The new ligands (E)-4-[2-(4-(N-methyl-N-hexadecylaminophenyl)ethenyl]pyridine (L¹) and 4′-(C₆H₄-p-N(Me)(hexadecyl))-2,2′:6′,2″-terpyridine (L²) were prepared along with their complexes [cis-Ir(CO)₂ClL¹], [fac-Os(CO)₃Cl₂L¹], [ZnCl₂L²] and [IrCl₃L²]. Whereas these complexes show a large second-order nonlinear optical (NLO) response at the molecular level, similar to that of related organic alkylated salts as evidenced by the Electric Field Induced Second-Harmonic (EFISH) generation technique, their Langmuir–Blodgett (LB) film susceptibility is lower than that of the salts.     

Theoretical study of tricyclo[3,3,1,1]decane, tricyclo[3,3,1,1]decsilane molecules and their halogen derivatives, C10H12X4 and Si10H12X4 (X=F, Cl, Br, I)

The B3LYP/3-21G* ab initio molecular orbital method from the program package was applied to study tricyclo[3,3,1,1^3,7]decane and tricyclo[3,3,1,1^3,7]decsilane molecules and their halogen derivatives (1,3,5,7-tetrahalotricyclo[3,3,1,1^3,7]decane and 1,3,5,7-tetrahalotricyclo[3,3,1,1^3,7]decsilane, C₁₀H₁₂X₄ and Si₁₀H₁₂X₄ respectively). The optimized structures of these compounds were obtained. Ionization potentials, HOMO and LUMO energies, energy gaps, heats of formation, atomization energies and vibration frequencies were calculated. The calculations indicate that these molecules are stable and have T_d symmetry. Tricyclo[3,3,1,1^3,7]decsilane and its halogen derivatives (Si₁₀H₁₂X₄) are found to have higher conductivity than tricyclo[3,3,1,1^3,7]decane and its halogen derivatives (C₁₀H₁₂X₄). 1,3,5,7-Tetrafluorotricyclo[3,3,1,1^3,7]decane (C₁₀H₁₂F₄) and 1,3,5,7-tetrafluorotricyclo[3,3,1,1^3,7]decsilane (Si₁₀H₁₂F₄) were found to be the easiest compounds to form and the most difficult to dissociate of all 1,3,5,7-tetrahalotricyclo[3,3,1,1^3,7]decane and 1,3,5,7-tetrahalotricyclo[3,3,1,1^3,7]decsilane compounds, respectively.     

Synthesis and Fluorescence of a New Active Material for Electrochemiluminescent Sensor:Ru(phen)2[phen-NHCO(CH2)4Br](PF6)2

Recently, much attention has been paid to Ru(II) complexes because of their excellent properties of photochemistry, phtophysis. Bis(2,2'-bipyridine)[4-methyl-4'-(6-bromohexyl)-2,2'-bipyridine] ruthenium(II) perchlorate has been used as an active material for electrochemiluminescent (ECL) sensor for selective detection of oxalic acid.It is known that ECL efficiency of Ru(phen)₃²⁺ is much higher than that of Ru(bpy)₃²⁺. In order to make out more efficient ECL sensor, we have designed and synthesized a new Ru(II) complex, Ru(phen)₂[phen-NHCO(CH₂)₄Br](PF₆)₂.     

Synthesis and thermal decomposition of substituted [2-(acyloxy)alkyl]diorganotin compounds, Bu2Sn(X)CH2 CHROCOR (X = halogen 2,4-pentanedionate or OCOR), potential sources of organotin catalysts

Halido-, (2,4-pentadionato-O,O′) and (acyloxy[2-(acyloxy)ethyl]dibutylstannanes, Bu₂Sn(X)CH₂CHR¹OCOR² (X = halogen, 2,4- pentanedionate, or OCOR) have been prepared, either by hydrostannation of vinyl esters or by condensation of stannyllithium compounds with epoxides followed by esterification. These thermally unstable compounds are easily decomposed in diorganotin compounds with two heteroatom donors. Some are good catalyst sources for silicone curing and polyurethane preparation.     

Novel Oxidative Coupling of 2-Naphthols to 1,1'-Bi-2-naphthols Catalysed by Solid Lewis Acids Using Atmospheric Oxygen as Oxidant

l,l'-Bi-2-naphthol derivatives have wide applications as chiral inducing agents for asymmetric synthesis.¹ There are many good methods for resolution of racemic binaphthols to give enantiomeric binaphthols.² Therefore, it is essential to established simple, convenient, economically and environmental-friendly methods for preparation of racemic l,l'-binaphthol derivatives. A number of methods have been developed for the oxidative coupling of 2-naphthols usually by using Fe³⁺, Cu²⁺ or Mn³⁺ as oxidants. The reaction were carried out in organic solvent,^3a in solid state^3b and in aqueous Fe³⁺ solution.^3c However, all those cases by employing excess, usually 2 equivalents of oxidant. The excess Fe³⁺, Cu²⁺ and the resulted Fe²⁺, Cu⁺ and HCl were not acceptable from a view point of environmental protection. Recently, Sakamoto et at⁴ and Kantam et at⁵ independently reported two catalytic oxidative coupling procedure for preparation of l,l'-binaphthols using aerial oxygen as oxidant and Cu²⁺-exchanged montmorillonite as catalysts. However, both procedures were by using some toxic chlorobenzene as solvent and long reaction time (>2 h) and high temperature(>140℃) were needed. Consquently, there is still a great demand for catalytic oxidative coupling 2-naphthols to generate binaphthols under mild conditions, environmentally friendly procedure and rapid process. Herein we report novel oxidative coupling of to 1,1-bi-2-naphthols (2a, 2b) catalysed by a number of supported reagents using aerial oxygen as oxidant. The results are listed in Table 1.