2-苯基4，5-二（2′-吡啶基）咪唑的合成

以苯甲醛和1，2-(2′-吡啶基)-乙二酮为原料，用德布斯法合成了未见报道的2-苯基4，5-二(2′-吡啶基)咪唑，收率31％，其结构经^1HNMR，IR和MS表征。     

2-苯基-4,5-二(2''''-吡啶基)咪唑的合成

以苯甲醛和1,2-(2'-吡啶基)-乙二酮为原料,用德布斯法合成了未见报道的2-苯基-4,5-二(2'-吡啶基)咪唑,收率31%,其结构经1H NMR, IR和MS表征.     

1-(2-氯-4-吡啶基)-3-苯基脲的合成

氯氨基吡啶;氯吡啶基苯基脲;1-(2-氯-4-吡啶基)-3-苯基脲的合成     

4-(4-甲基苯基)-6-苯基-2,2′-二联吡啶芳炔铂(II)络合物的合成及光物理性质

设计合成以4-甲基苯基-6-苯基-2,2′-二联吡啶为主配体、芳炔为辅助配体的铂(II)络合物1-3.与苯乙炔、萘乙炔为辅助配体的络合物1,2相比,蒽乙炔4-(4-甲基苯基)-6-苯基-2,2′-二联吡啶铂(II)络合物MLCT激发态的能量升高.     

4’-羟基联苯-4-甲酸、1, 3-二吡啶基丙烷构筑的一维镉配位聚合物的晶体结构和荧光性质

水热条件下采用Cd(NO3)2·4(H2O),4′-羟基联苯-4-甲酸和1,3-二吡啶基丙烷作为反应物合成出一个新的一维镉配位聚合物{[Cd(4′,4-Hhbc)2(bpp)2]}n(1)(4′,4-H2hbc=4′-羟基联苯-4-甲酸,bpp=1,3-二吡啶基丙烷),并分别用元素分析、红外光谱、差热分析、X-射线粉末衍射、紫外吸收光谱和X-射线单晶衍射等表征了该结构。晶体结构分析结果表明:μ2桥联的1,3-二吡啶基丙烷将镉金属离子连接成一维链结构。荧光分析表明常温固态下配合物1发射蓝色荧光,且在440 nm处的荧光寿命为3.2 ns。     

反-4-(4-R-苯乙烯基)吡啶光二聚反应的研究

通过反-4-(4-R-苯乙烯基)吡啶[R=H(Ⅰa),Me(Ⅰb),OMe(Ⅰc),OH(Ⅰd),Me2N(Ⅰe)］在稀盐酸中的光二聚反应合成了4个r-1,c-2,t-3,t-4-1,3-双(4-R-苯基)-2,4-二(4-吡啶基)环丁烷[R=H(Ⅱa),Me(Ⅱb),OMe(Ⅱc),OH(Ⅱd)］,除Ⅱa外,其余为新化合物.光二聚反应具有高度立体选择性且几乎是定量完成的.研究发现,随着取代基供电子能力的提高,光二聚反应速率下降.反应的高度立体选择性以及该反应不受空气中氧气影响的事实表明光二聚反应是按激发单重态历程进行的.研究还发现Ⅰa～Ⅰd在有机溶剂中主要发生反-顺异构化反应,随着溶剂极性增加,反-顺异构化速度加快,表明其反-顺异构化反应亦经激发单重态历程.本文检测到了Ⅰa在稀盐酸溶液中的激基缔合物荧光.     

4-二甲氨基吡啶手性类似物2-[2-(4-二甲氨基吡啶基)]环己醇的合成

从2-[2-(4-氯吡啶基)]环己酮出发,经NaBH4还原,然后再与二甲胺水溶液反应得到消旋的2-[2-(4-二甲氨基吡啶基)]环己醇,采用(L)-DTTA(二对甲基苯甲酰基酒石酸)进行拆分得到对映纯的路易斯碱催化剂4-二甲氨基吡啶类似物(1R,2S)-2-[2-(4-二甲氨基吡啶基)]环己醇.     

2,6-二甲基-3,5-二氯-4-吡啶酚糖苷的合成

在相转移催化条件下, 使 a-D-乙酰基化溴代的葡萄糖、半乳糖、葡萄糖醛酸甲酯1a, 1b, 1c分别与2,6-二甲基-3,5-二氯-4-吡啶酚(俗称氯吡醇, 氯羟吡啶)作用, 合成了氯吡醇的糖苷: 1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4,6-四-O-乙酰基-β-D-葡萄吡喃糖苷(2a), 1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4,6-四-O-乙酰基β-D-半乳吡喃糖苷(2b), 1-O-(2'6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4-三-O-乙酰基-β-D-葡萄吡喃糖醛酸甲酯(2c)。2a, 2b, 2c分别在甲醇中氨解, 相应得到: 1-O-(2', 6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-葡萄吡喃糖苷(3a), 1-O(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-半乳吡喃糖苷(3b),1-O-(2', 6'-二甲基-3',5'-二氯-(4'-吡啶基)-β-D-葡萄吡喃糖醛酸酰胺(3c)。2c用CH~3ONa/CH~3OH处理, 得到1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-葡萄吡喃糖醛酸甲酯(3d)。     

1-芳基-3，5-二甲基吡唑-4-羧酸有机锡酯的合成、结构及杀菌活性研究

由1-芳基-3,5-二甲基吡唑-4-羧酸与适当的有机锡反应,合成表征了一系列的1-芳基-3,5-二甲基吡唑-4-羧酸有机锡酯(1～14),并通过单晶衍射确定了1-苯基-3,5-二甲基吡唑-4-羧酸三乙基锡酯(7)的结构。该化合物与一分子水共同结晶,通过分子间O-H…O及O-H…N氢键形成二维网状结构。杀菌活性筛选表明新合成的化合物对于番茄早疫菌、花生褐斑菌、小麦赤霉菌、苹果轮纹菌及灰霉菌全部具有良好的生长抑制作用。1-苯基-3,5-二甲基吡唑-4-羧酸三乙基锡酯及1-(2-吡啶基)-3,5-二甲基吡唑-4-羧酸三乙基锡酯在50μg.mL-1浓度下的体外实验中表现出很高的生长抑制率。对于高活性的三取代锡羧酸酯进行了EC50值的测定,结果表明1-(2-吡啶基)-3,5-二甲基吡唑-4-羧酸三乙基锡酯对苹果轮纹菌的EC50值为0.06μg.mL-1,对小麦赤霉菌的EC50值为0.14μg.mL-1。     

1,3-二(4-吡啶基)丙烷Cd(Ⅱ)配合物的合成、晶体结构及发光性质研究

以1,3-二(4-吡啶基)丙烷(L)为配体,合成了一种新的Cd(Ⅱ)配合物{[CdL2(H2O)2].2(C7H6N5)}n(C7H6N5=5-(3-氨基苯基)四唑离子)。X射线单晶衍射结构分析表明该配合物为一维链状结构,Cd(Ⅱ)分别与4个1,3-二(4-吡啶基)丙烷配体的4个氮原子,2个配位水分子的氧原子形成了六配位的扭曲八面体几何构型,1,3-二(4-吡啶基)丙烷配体桥梁相邻的Cd(Ⅱ)离子形成了一维的无限延伸的链状结构,分子间通过O-H…N、N-H…N氢键作用构筑成三维超分子网络结构。     

杂芳基乙烯光化学反应的研究 2: r-1, c-2, t-3, t-4-1, 3-二(4-甲基苯基)-2, 4-二(4-吡啶基)环丁烷的结构及光解反应

通过反-1-(4-甲基苯基)-2-(4-吡啶基)乙烯(E-MEP)在稀盐酸中的光二聚反应得到了接近定量的标题化合物(DMDPC)。用元素分析,IR, UV, 1H NMR和MS表征了其结构, 并用X射线衍射法测定了DMDPC的晶体结构。DMDPC属单斜晶系, 空间群为P21/c, 晶胞参数a=1.1376(6), b=1.7379(8), c=1.1590(5)nm, β=106.16(4)ⅲ, Z=4。由于四元环同侧苯环和吡啶环的相互排斥作用, DMDPC采取蝶式构象。研究发现, DMDPC在短波紫外光照射下易发生开环反应; 同时还发现,E-MEP与其顺式异构体(Z-MEP)间的反-顺异构化平衡受照射光波长控制。     

Synthesis and Crystal Structure of Rctt-1-(2-benzoxazolyl)-2-(4-chlorophenyl)-4-phenyl-3-(4-pyridinyl)cyclobutane

1INTRODUCTIONThephotodimerizationof1,2-bisarylethenederivativesisaconvenientwayforsynthesizingtetraarylsubstitutedcyclobutane.Forthisreason,thephotochemistryofstilbeneandstyrylpyridinederivativeshasbeenextensivelystudied[1,2].UpontheirradiationwithUVlight(?=300～400nm),thesemonomersareconvertedtohead-to-tailphotodimersinpolarsolventwithperfectyields.Inrecentyears,ourgrouphasbeenstudyingthephotodimerizationreactionsofheteroarylethenescontainingbenzoxazolyl[3]andphenyloxazolyl[4]groups.Itw…     

Synthese von 3-(2-Carboxy-4-Pyridyl)- und 3-(6-Carboxy-3-pyridyl)-DL-alanin

Synthesis of 3-(2-Carboxy-4-pyridyl)-and 3-(6-Carboxy-3-pyridyl)-DL-alanine As starting materials for potential photochemical approaches to betalaines C(R = COOH) and to muscaflavine F(R = COOH), β-(2-carboxy-4-pyridyl)- and β-(6(carboxy-3-pyridyl))-DL-alanine ( A and D with R = COOH or 4 and 11 ), respectively, were prepared (Scheme 1). The synthesis of 4 (= A, R = COOH) started with the 2-[(4-pyridyl)methyl]malonate 1 and proceeded via the N-oxide 2 , cyanation and hydrolysis (Scheme 2). Amino acid 11 was obtained from (3-pyridyl)methyl-bromide ( 6 ) via the malonate 7 by an analogous sequence of reactions (Scheme 3).     

Ligand-Driven Light-Induced Spin Change in Transition-Metal Complexes: Selection of an Appropriate System and First Evidence of the Effect, in Fe(II)(4-styrylpyridine)(4)(NCBPh(3))(2)

The first observation of a ligand-driven light-induced spin-state change (LD-LISC effect) in a transition-metal complex is reported. The compounds under investigation are of the type Fe(II)L(4)X(2), where L is a cis/trans photoisomerizable ligand. For an iron(II) spin-state change to result from ligand cis <--> trans conversion, the Fe(II)(trans-L)(4)X(2) species had to exhibit a thermally-induced high-spin state <--> low-spin state crossover. This property was checked by variable-temperature magnetic susceptibility measurements, for compounds with X(-) = NCBPh(3)(-) or NCBH(3)(-) and L = 1-phenyl-2-(4-pyridyl)ethene (or 4-styrylpyridine, abbreviated as Stpy), 1-(4-R-phenyl)-2-(4-pyridyl)ethene (R = CH(3), COOCH(3)), or 1-(1-naphthyl)-2-(4-pyridyl)ethene. The results are comparatively discussed. The best candidate for the LD-LISC effect to be observed is found to be Fe(Stpy)(4)(NCBPh(3))(2): the complex (C(t)) formed with trans-Stpy undergoes a thermally-induced spin crossover centered around 190 K; the one (C(c)) formed with cis-Stpy retains the high-spin state at any temperature. Photoisomerization of the Stpy ligand, at 140 K, in the complex embedded within a cellulose acetate matrix, is effectively shown, on the basis of UV-vis absorption measurements, to trigger the spin-state change of the iron(II) ions.     

Two new Co(II) and Ni(II) complexes with 3-(2-Pyridyl)pyrazole-based ligand: synthesis, crystal structures, and bioactivities

Two new Co(II) and Ni(II) complexes exhibiting DNA cytotoxic activities with 3-(2-pyridyl)pyrazole-based ligand, [Co(L)(3)](ClO(4))(2) (1) and [Ni(L)(3)](ClO(4))(2) (2) (L=1-[3-(2-pyridyl)-pyrazol-1-ylmethyl]-naphthalene) were synthesized and structurally characterized. Both 1 and 2 crystallized in the monoclinic system, space group P2(1)/c, for 1, a=12.8324(8), b=12.1205(8), c=33.27(2) A, beta=93.92(3) degrees and Z=4; for 2, a=12.8764(3), b=12.1015(3), c=33.2415(9) A, beta=93.998(1) degrees and Z=4. Among them, the Co(II) and Ni(II) ions were all coordinated by six N donors from three distinct L ligands. In addition, the cytotoxic activities of 1, 2 and L in vitro were evaluated against three different cancer cell lines HL-60 (human leukemia), BGC-823 (stomach cancer) and MDA-MB-435 (mammary cancer), respectively. The results showed that 1 exhibited significantly high cytotoxic activities against HL-60 and moderate activities against BGC-823 and MDA-MB-435. In order to further investigate the relationships between structures and DNA-binding behaviors of these complexes, the interactions of 1, 2 and L with calf thymus DNA (CT-DNA) were then subjected to thermal denaturation, viscosity measurements and spectrophotometric methods. The results indicated that 1 and 2 intercalated with DNA via L ligand. The intrinsic binding constants of 1, 2 and L with DNA were 1.6x10(4), 5.6x10(3) and 2.76x10(3) M(-1), respectively.     

Syntheses, structural characterization and photophysical properties of 4-(2-pyridyl)-1,2,3-triazole rhenium(I) complexes

Novel chelators, i.e., 4-(2-pyridyl)-1,2,3-triazole derivatives, were synthesized by means of Cu(I)-catalyzed 1,3-dipolar cycloaddition and used to prepare luminescent Re(I) complexes [ReCl(CO)(3)(Bn-pyta)], [ReCl(CO)(3)(AcGlc-pyta)] and [ReCl(CO)(3)(Glc-pyta)] (Bn-pyta = 1-benzyl-4-(2-pyridyl)-1,2,3-triazole, AcGlc-pyta = 2-(4-(2-pyridyl)-1,2,3-triazol-1-yl)ethyl 2,3,4,6-tetra-O-acetyl-beta-d-glucopyranoside, Glc-pyta = 2-(4-(2-pyridyl)-1,2,3-triazol-1-yl)ethyl beta-d-glucopyranoside). X-Ray crystallography of Bn-pyta and Glc-pyta indicated an azocompound-like structure while the 1,2,4-triazole isomer has an azine character. [ReCl(CO)(3)(Bn-pyta)] crystallized in the monoclinic system with space group P2(1)/n. Bn-pyta ligand coordinates with the nitrogen atoms of the 2-pyridyl group and the 3-position of 1,2,3-triazole ring, which is a very similar coordinating fashion to that of the 2,2'-bipyridine derivative. The glucoconjugated Re(I) complexes [ReCl(CO)(3)(AcGlc-pyta)] and [ReCl(CO)(3)(Glc-pyta)] hardly crystallized, and were analyzed by applying extended X-ray absorption fine structure (EXAFS) analysis. The EXAFS analyses suggested that the glucoconjugation at the 1-position of the 1,2,3-triazole makes no influence to the coordinating fashion of 4-(2-pyridyl)-1,2,3-triazole. [ReCl(CO)(3)(Bn-pyta)] showed a blue-shifted maximum absorption (333 nm, 3.97 x 10(3) M(-1) cm(-1)) compared with [ReCl(CO)(3)(bpy)] (371 nm, 3.35 x 10(3) M(-1) cm(-1)). These absorptions were clearly assigned to be the mixed metal-ligand-to-ligand charge transfer (MLLCT) on the basis of time-dependent density functional theory calculation. The luminescence spectrum of [ReCl(CO)(3)(Bn-pyta)] also showed this blue-shifted feature when compared with that of [ReCl(CO)(3)(bpy)]. The luminescence lifetime of [ReCl(CO)(3)(Bn-pyta)] was determined to be 8.90 mus in 2-methyltetrahydrofuran at 77 K, which is longer than that of [ReCl(CO)(3)(bpy)] (3.17 micros). The blue-shifted electronic absorption and elongated luminescence lifetime of [ReCl(CO)(3)(Bn-pyta)] suggested that 4-(2-pyridyl)-1,2,3-triazole functions as an electron-rich bidentate chelator.     

Ultrafast excited-state dynamics preceding a ligand trans-cis isomerization of fac-[Re(Cl)(CO)3(t-4-styrylpyridine)2] and fac-[Re(t-4-styrylpyridine)(CO)3(2,2'-bipyridine)]+

UV-vis absorption and resonance Raman spectra of the complexes fac-[Re(Cl)(CO)3(stpy)2] and fac-[Re(stpy)(CO)3(bpy)]+ (stpy = t-4-styrylpyridine, bpy = 2,2'-bipyridine) show that their lowest absorption bands are dominated by stpy-localized intraligand (IL) pi pi* transitions. For the latter complex a Re --> bpy transition contributes to the low-energy part of the absorption band. Optical population of the 1IL excited state of fac-[Re(Cl)(CO)3(stpy)2] is followed by an intersystem crossing (< or =0.9 ps) to an 3IL state with the original planar trans geometry of the stpy ligand. This state undergoes a approximately 90 degrees rotation around the stpy C=C bond with a 11 ps time constant. An electronically excited species with an approximately perpendicular orientation of the phenyl and pyridine rings of the stpy ligand is formed. Conversion to the ground state and isomerization occurs in the nanosecond range. Intraligand excited states of fac-[Re(stpy)(CO)3(bpy)]+ show the same behavior. Moreover, it was found that the planar reactive 3IL excited state is rapidly and efficiently populated after optical excitation into the Re --> bpy 1MLCT excited state. A 1MLCT --> 3MLCT intersystem crossing takes place first with a time constant of 0.23 ps followed by an intramolecular energy transfer from the ReI(CO)3(bpy) chromophore to a stpy-localized 3IL state with a 3.5 ps time constant. The fast rate ensures complete conversion. Coordination of the stpy ligand to the ReI center thus switches the ligand trans-cis isomerization mechanism from singlet to triplet (intramolecular sensitization) and, in the case of fac-[Re(stpy)(CO)3(bpy)]+, opens an indirect pathway for population of the reactive 3IL excited state via MLCT states.     

Reactions of 2-nitro-2-(4-pyridyl) propane with nucleophiles. Substitution at tertiary carbon

The reaction of 2-nitro-2-(4-pyridyl) propane (I) with lithium 2-propanenitronate, lithium cyclohexanenitronate, and sodium thiophenoxide affords excellent yields of the C-alkylation products 2-nitro-3-(4-pyridyl)-2,3-dimethylbutane (II), 2-(4-pyridyl)-2-(1-nitrocyclohexyl) propane (V) and 2-thiophenyl-2-(4-pyridyl) propane (VI), respectively. In contrast, the reaction of compound I with sodium azide does not afford the expected tertiary azide; but instead gives the dimer 2,3-bis(4-pyridyl)-2,3-dimethylbutane (III), in near quantitative yield. Evidence has been obtained that all of these transformations proceed via electron transfer pathways.