On the Mechanism of Condensation between 5—Amino—4,6—dichloro—2—methylpyrimidine and 1—Acetyl—2—imidazolin—2—one

The condensation reaction between 5-amino-4,6-dichloro-2-methylprimidine and 1-acetyl-2-imidazolin-2-one using POCl3 as solvent gave 4,6-dichloro-2-methyl-5-(1-acetyl-tetra-hydro-imidazo-2-ylidene)-aminopyrimidine predominantly and 4,6-dichloro-2-methyl-5-{1-1-(2-oxo-tetrahydro-imidazolyl)]-acetene}-aminopyrimidine as by-product. No 4,6-dichloro-2-methyl-5-(1-acetyl-2-imidazolin-2-yl)-aminopyrimidine was found. The result indicated an esterifi-cation-addition-elimination mechanism.     

5—（5—氯—2—吡啶偶氮）—2，4—二氨基甲苯吸光光度法测定微量镍研究

在SDS存在下 ,于 pH 5 .5～ 6.5水溶液中 ,5 (5 氯 2 吡啶偶氮 ) 2 ,4 二氨基甲苯 (5 Cl PADAT)与镍 (Ⅱ )形成稳定的紫红色配合物 ,其最大吸收波长位于 5 4 5nm处 ,表观摩尔吸光系数为 1.0 2× 10 5L·mol- 1·cm- 1,配合物中镍与试剂的组成比为 1∶2 ,镍浓度在 0～ 4 μg/ 10ml范围内服从比耳定律。在硫脲、氟化铵和焦磷酸钠存在下 ,方法具有良好的选择性 ,用于镁合金、矿样和钢样中微量镍的测定 ,结果满意     

2—（5—溴—2吡啶偶氮）—5—二乙氨基酚在光度分析应用中的新进展

2-(5溴-2吡啶偶氮)-5-二乙氨基酚(简称5-BrPADAP)系吡啶基偶氮化合物中最典型的高灵敏显色剂。自70年代末,我国分析工作者就开始研究了在光度分析中的应用。有关该试剂的性能及其至80年代初期的应用现状已有专题综述。此后,近十年期间,随着表面活性剂的广泛应用,以及各种消除干扰途径的开拓,使其扩大了在光度分析中的应用范围。本文就1984年以来国内的一些工作状况加以归纳。 1 在有色合金、环境样品分析中的应用 铁 在pH 5.0HOAc-NaOH缓冲介质中,在Tri-ton X-100存在下,Fe(Ⅱ)与试剂所形成的紫红色配合物有两个吸收峰。分别为558nm与746nm,746nm为特征吸收,s=2.63×10~4,虽然,在此波长下灵敏度要降低些,但其他能与试剂显色的金属离子均无吸收。因此,在无任何掩蔽剂存在下,可选择性地用于镁、铝合金中微量铁的测定。容庆新等在pH 6 HOAc-NaOAc缓冲介质中,选择乙醇作增溶剂,用硫脲、四乙烯五胺及EDTA掩蔽Cu、M、Co等离子的干扰,该法用于铜合金、铝、镁合金中微量铁的测定,同时也可用于电炉渣、白云石、镁砂等样品中铁的测定。 锰 在pH 9.7～10.4 NH_4OH-NH_4Cl缓冲介质中,在CTMAB存在下,Mn(Ⅱ)与试剂瞬间形成紫红色配合物,λ_(max)=568nm,ε=1.21×10~5,0～17.5μg/     

Crystal Structure of 5—（l—Menthyloxy）—3—chloro—4— Pyrrolidinyl—2（5H0—f

The molecular structure of the title compound 5-(l-menthyloxy)-3-chloro-4-pyrrolidinyl-2(5H)-furanone, C18H28ClNO3(Ⅰ), has been determined by X-ray diffraction at 296(1)K. The crystal is monoclinic with space group P21, a=9.457(3), b=10.413(3), c=9.525(2), β=95.19(2)°, V=934(1) 3, Z=2, Mr=341.88, Dx=1.22 g/cm3, μ=2.15 cm-1, F(000)=368. The final R factor is 0.059, and Rw is 0.065 for 1020 observed reflections with I≥3σ(I). The absolute configuration at C(14) of the acetal carbon was proved to be S, taking into account the known configuration of 1R, 2S, 5R-menthyl moiety. There are three rings in the molecule of this compound: the furanone ring, the pyrrolidine ring and the mentholoxy group ring. The franone ring is connected with the pyrrolidine ring and the mentholoxy ring by N atom and μ2-O bridge atom respectively.     

Michael Addition Reaction without Catalyst：The Synthesis of 2—Amino—5,6,7,8—tetrahydro—5—oxo—4—aryl—7,7—dimethyl—4H—benzo—[b]—pyran Derivatives

A serices of tetrahydrobenzo-[b]-pyran derivative was synthesized by the reaction of arylmethylene malononitrile or arylmethylene cyanoacetate with dimedone in ethylene gylcol at 80℃ without catalyst. The structures of the two products were characterized by X-ray diffraction.