Contribution to the reaction of alkaloids with potassium tetraiodomercurate

Summary The products of the reaction of alkaloids with potassium tetraiodomercurate (Mayer's reagent) have been investigated by melting point examinations. Three structural types of composition are suggested depending on the kind of alkaloid and on the concentration ratios applied. The following alkaloids have been employed: codeine, atropine, papaverine, quinine, (pyridine, acridine).

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Beitrag zur Reaktion von Alkaloiden mit Kaliumtetrajodomercurat (Mayer's Reagens)III. Untersuchung der Reaktionsprodukte

Zusammenfassung Die Reaktionsprodukte wurden hinsichtlich ihrer Schmelzpunkte untersucht und drei Strukturtypen aufgestellt, die von der Art des Alkaloids und den angewandten Konzentrationsverhältnissen abhängig sind. Die folgenden Alkaloide wurden untersucht: Codein, Atropin, Papaverin, Chinin, (Pyridin, Acridin).

     

The reaction of Lawesson's reagent with trihydroxy compounds

Lawesson's reagent (1a) reacts with pyrogallol (2) to give 1,3,2‐benzodioxaphospholane‐2‐sulfide (3) and with 1,8,9‐trihydroxyanthracene to give 13. The structures of the products have been established either chemically, using methanolysis and methylation, or spectroscopically. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 25–30, 1999     

Polynuclear Cu(II), Ni(II) and Cd(II) coordination compounds with bis(pyrimidin-2-yl)amine and dicyanamide

In this study the synthesis, crystal structure and characterization of three new transition metal polynuclear compounds with formula [Cu(dipm)(μ-dca)₂]_n(H₂O) (1), [Ni(dipm)(μ-dca)₂]_n(C₂H₆O)_1/2 (2) and [Cd(dipm)(μ-dca)₂]_n (3) (in which dipm = bis(pyrimidin-2-yl)amine and dca = dicyanamide) are reported. The isostructural compounds 1 and 2 contain a double-bridging end-to-end dca unit connecting two metal ions and a single bridging end-to-end dca unit between subsequent metals. Compound 3 exhibits only single bridging end-to-end dca units, oriented in three directions, giving rise to a 3D framework.     

Ni(II)-catalyzed Conia-ene reaction of 1,3-dicarbonyl compounds with alkynes

[reaction: see text]. We have discovered a Ni(II)-catalyzed Conia-ene reaction of 1,3-dicarbonyl compounds with alkynes. In the presence of Ni(acac)2 and Yb(OTf)3, various acetylenic 1,3-dicarbonyl compounds underwent Conia-ene reaction to give mono- and bicyclic olefinic cyclopentanes. A mechanism involving the enol-yne-Ni complex formation is proposed and supported by deuterium-labeling experiments.     

Aldehyde-selective addition of alkynylchromium compounds prepared by reduction of alkynyl halides with chromium(II) reagent

Alkynyl halides are reduced by chromium(II) chloride in DMF to give unisolable alkynylchromium compounds which add selectively to an aldehyde moiety without affecting the coexisting ketone group of the substrate.     

2-(4-Toluenesulphonamido)aniline as an analytical reagent : The nature of the reaction with copper(II)

2-(4-Toluenesulphonamido)aniline,TSA, was examined to evaluate the claim that it is a specific gravimetric reagent for copper(II) and to see if the application of the reagent could be extended. The nature of the reaction and complexes was investigated by potentiometry, solvent extraction, spectrophotometry, polarography and mass spectrometry. A 1:2 copper: TSA complex formed at pH 6 (K₁=10^19.11 in 50% (v/v) aqueous dioxane) is suitable for the gravimetric determination, as previously reported. A violet complex (λ_max. 550 nm, ε=6620) of uncertain composition is formed at pH 10–11 and may be used for the spectrophotometric determination of copper. The centres of chelation have been deduced from the infrared spectra of the complex and reagent and the causes of the selectivity are discussed.     

Contribution to the crystal chemistry of tetrametaphosphates(II)

Chemical preparations and crystal structures of two hydrated forms of CsNa₃P₄O₁₂ are described. CsNa₃P₄O₁₂ · 4H₂O with a = 14.50(2), b = 7.804(3), c = 7.006(3)Å crystallizes in space group Imm2, Z = 2. The crystal structure has been determined using 745 independent reflexions with a final R value of 0.028 (R = 0.040 with the 934 collected reflexions), CsNa₃P₄O₁₂ · 3H₂O with a = 11.39(1), b = 10.92(1), c = 11.81(1)Å, β = 95.24(5)° in $\text{P2}{}_1\text{c}\text{, Z = 4}$. The crystal structure has been solved with 2975 independent reflexions with a final R-value of 0.018 (R = 0.057 with all the 6531 collected reflexions). In both structures there are four-membered rings built up with corner-sharing phosphate tetrahedron. For the tetrahydrate, the ring symmetry is mm whereas in the trihydrate, one observes two independent ring anions of symmetry $\text{1}$. In both cases hydrogen atoms have been located and refined.     

Reactions of palldium(II) compounds with carbon monoxide in alcohol/amine systems : a new route to palladium(O) carbonyl and carboalkoxy-palladium(II) complexes

Palladium(O) carbonyl complexes, Pd(CO)(PPh₃)₃ Pd₃(CO)₃(PPh₃)₃ and Pd₃(CO)₃(PPh₃)₄, can conveniently be prepared by the reaction of (PPh₃)₂PdCl₂ with carbon monoxide at room temperature in methanol/amine systems involving primary and secondary amines such as diethylamine and cyclohexylamine. These carbonyl complexes are interconvertible under suitable conditions. On the other hand, use of tertiary amine such as triethylamine and tri-n-butylamine in place of the above amines give selectively a carbomethoxy complex (PPh₃)₂PdCl(COOCH₃).     

Influence of the reaction conditions on the self-assembly of lead(II) 5-sulfosalicylate coordination polymers with chelating amine ligands

The synthesis and crystal structures of [Pb(Hssal)(2,2'-bipy)(DMF)]n (1), [Pb(Hssal)(2,2'-bipy)(H2O)]n (2), [Pb(Hssal)(phen)(DMF)]n (3), and [Pb3(ssal)2(phen)3]n (4) were reported, where Hssal2- and ssal3- are doubly and fully deprotonated 5-sulfosalicylates, 2,2'-bipy is 2,2'-bipyridine, and phen is 1,10-phenanthroline. Compounds 1-4 were synthesized by the various reaction conditions, such as reaction temperature, molar ratio, and pH, and these structures are formed by infinite chains or layers where Pb(II) ions are linked by Hssal2- or ssal3- bridges. Compound 1, which has a ladderlike chain, was formed in DMF/H2O. Compound 2 with a H2O molecule coordinated to Pb(II) was prepared by a hydrothermal reaction. Compounds 3 and 4 were synthesized in a higher pH compared to compounds 1 and 2, containing the 2,2'-bipy ligand. In 1-3, 5-sulfosalicylates are doubly deprotonated, whereas in 4, 5-sulfosalicylate is fully deprotonated. Coordination modes of Hssal2- and ssal3- ligands in 1-4 are novel and are first reported in this presentation. Although compounds 1 and 3 have the same structural topology, their aromatic-aromatic interactions are significantly different. The coordination spheres of Pb(II) ions in 1 and 3 are holodirected, whereas in 2 and 4, they feature somewhat hemidirected properties with small holes or gaps. Compound 4 exhibits some interesting features that (1) there is not any solvent in the structure, (2) there are extensively aromatic-aromatic stacking interactions among aromatic rings, and (3) there is also a weak interaction between Pb(II) atoms in the trinuclear motif.     

Generation of metalated thiophenes with Grignard reagent and catalytic secondary amine for the cross coupling reaction with aryl halides

The reaction of thiophene derivatives with Grignard reagent (EtMgCl) and a catalytic amount of amine (Cy₂NH) induced the metalation at the α-position. Following addition of several aryl halides in the presence of a nickel or palladium catalyst afforded C-H arylated products in good to excellent yields. The method was successfully applied to facile synthesis of differently-substituted 2,5-diarylthiophenes.     

Coordination compounds of palladium(II) and platinum(II) with benzotriazoles

Summary The nitrogen-donor ligands 1-methylbenzotriazole (1Mebta), 5-methylbenzotriazole (5MebtaH), 5-chlorobenzotriazole (5ClbtaH) and 5-nitrobenzotriazole (5NO₂btaH) react with palladium(II) and platinum(II) to give cis-[PdL₂Cl₂], cis-[PtL₂Cl₂] (L = 1Mebta, 5MebtaH, 5ClbtaH or 5NO₂btaH), [Pt(5ClbtaH)₄]Cl₂, [Pd-(5MebtaH)Cl₂]₂, [Pd(5ClbtaH)Cl₂]₂ and [Pd(5NO₂btaH)-Cl₂]₂. The complexes were characterized by physicochemical and spectroscopic methods. The benzotriazoles act as monodentate ligands binding through N(3). Monomeric square planar structures are assigned for the 12 complexes and [Pt(5ClbtaH)₄]Cl₂ in the solid state. Centrosymmetric, chloro-bridged, dinuclear square planar structures of C_2h symmetry are proposed for the 11 palladium(II) compounds.     

“Palladiazo” a new selective metallochromic reagent for palladium: Part I the main characteristics of the pure reagent and its reaction with palladium(II)

The synthesis and purification of 2,7-bis(4-azophenylarsono)-1,8-dihydroxy-naphthalene 3,6-disulphonic acid is reported. Because of its selectivity for palladium-(II), the name palladiazo is suggested for the reagent. Aqueous solutions of palladiazo are very stable and exhibit 2 absorption maxima located at 540 and 625 nm, the molar absorptivities being 3.3 · 10⁴ and 1.7 · 10⁴, respectively. Palladiazo changes color stepwise and reversibly with increase in hydrochloric acid concentration from 0 to 13 M. A negatively charged complex of type M₂L₃ is formed with Pd(II) at pH 2.5–3.5, and shows an absorption maximum at 640 nm with a molar absorptivity of (5.7 ± 0.1) ·10⁴; the complex can be readily extracted with diphenylguanidine chloride or quaternary ammonium salts dissolved in n-butanol or higher alcohols. The complex obeys Beer's law at 675 nm in the concentration range 10–250 μg Pd(II)/50 ml. Pb(II), Bi(III), Ce(III) and the rare-earth elements are the only expected cationic interferences.     

伯胺N1923萃取Co(II)Ni(II)的平衡

298±1K下考察了伯胺N1923(B)与其硫氰酸盐共存, 用煤油作稀释剂时, 从1.00mol.dm^-^3(Na, H)SCN水相中萃取Co(II)或Ni(II)的平衡, 萃合物组成为(BH)2M(SCN)4.XB, X最大为4     

Formation of silver nanoparticles in the redox reaction of silver(I) nitrate with crystalline macrocyclic nickel(II) compounds

The redox reaction of crystalline macrocyclic nickel(II) carboxylates with silver(I), gold(III), and palladium(II) salts leads to the formation of nanoclusters of the corresponding metals. The reaction with silver nitrate was used to show that the size of the nanoparticles formed depends both on the chemical and crystal structure of the solid matrix and the reaction time. The results open the possibility of forming noble metal nanoparticles with desired dimensions and dispersion.     

Unusual reaction of beta-hydroxy alpha-diazo carbonyl compounds with Cl3CCN/NaH and Rh(II)-catalyzed reaction of beta-trichloroacetylamino alpha-diazo carbonyl compounds

The hydroxyl group was directly converted into the trichloroacetylamino group by reacting beta-hydroxy alpha-diazo carbonyl compounds with Cl(3)CCN and NaH. Rh(II)-catalyzed reactions of the beta-amino alpha-diazo carbonyl compounds were discussed. [reaction: see text]