Reaction of cyclic thioureas with chloroacylpiperazines

S-Alkylation products are formed in the reaction of tetrahydropyrimidine-2-thione and hexahydro-1,3-diazepine-2-thione with chloroacylpiperazines in dimethylformamide at room temperature; dihydrothiazolo[3,2-a]pyrimidine and tetrahydrothiazolo[3,2-a]-[1,3]diazepine systems are obtained in refluxing ethanol. It is shown that the S-alkyl derivatives are very readily converted to condensed systems.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–826, June, 1984.     

Relationship between ligand conformations and complexation properties in ditopic biphenyl thioureas

Four new homoditopic biphenyl thiourea derivatives have been prepared to be used in carboxylate sensing. Experiments carried out with these ligands have demonstrated that the conformation of the free ligand has a strong influence on both complex stoichiometry and geometry. High equilibrium constants were obtained in DMSO.     

Synthesis of cyclic bis- and trismelamine derivatives and their complexation properties with barbiturates

Cyclic bis- and trismelamine derivatives were prepared from cyanuric chloride by stepwise substitutions with appropriate amines. The complexation abilities of these melamine derivatives with barbituric acid derivatives were evaluated by UV-vis spectroscopy and (1)H NMR. The structure was also confirmed by X-ray crystallography. Both the acyclic and the cyclic bismelamine derivatives formed a 1 : 1 complex via six hydrogen bonds with barbituric acid derivatives. van't Hoff analyses on the complexation of the bismelamines with the barbituric acid derivative revealed that the complexation of the cyclic bismelamine was entropically favored and enthalpically less favored process than those of the acyclic bismelamine. X-Ray crystallographic analysis and (1)H NMR studies revealed that the cyclic trismelamine bound one barbituric acid derivative into the cavity via six hydrogen bonds by two melamine moieties and another barbituric acid via three hydrogen bonds by the residual melamine moiety.     

Reaction of functionally 4-substituted hexahydropyrimidine-2-thiones with sodium tetrahydroborate. Synthesis of six-membered cyclic thioureas

A new method was developed for the production of six-membered cyclic ureas based on the reaction of readily obtainable 4-azido-, 4-acetoxy-, or 4-phenylsulfonylhexahydropyrimidine-2-thiones with sodium tetrahydroborate. M. V. Lomonosov State Academy of Fine Chemical Technology, Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2. pp. 229–231, February. 1998.     

Synthesis of some pyridyl substituted ureas and thioureas

Thirty five pyridyl-substituted ureas and thioureas were synthesized in order to study the relationship between chemical structure and biological activity. These compounds were obtained by the reaction of pyridylamines with isocyanates and isothiocyanates, as well as by the desulfurization of the corresponding thioureas. When tested, all these compounds exhibited weak physiological activity.     

Synthesis of thiazoles from the reaction of phenyliodonium ylids of cyclic β-dicarbonyl compounds with thioureas

Phenyliodonium ylids of cyclic β-dicarbonyl compounds react with substituted thioureas to form the corresponding thiouronium ylids. The latter, when they have one free amino group, are converted upon heating to fused thiazoles. The reaction can be considered as a modification of the Hantzsch synthesis.     

Synthesis and characterization of tetraphenylphosphonium salts of N-phosphorylated thioureas and bis-thioureas

Russian Chemical Bulletin - Tetraphenylphosphonium salts of N-phosphorylated thioureas and bio-thioureas were synthesized by the reactions of their sodium salts with PPh4Br in 96% aqueous EtOH. The...     

Camphor-derived thioureas: Synthesis and application in asymmetric Kabachnik-Fields reaction

A series of camphor-derived thiourea organocatalysts 3a–f were designed and synthesized from(1R,3S)-camphoric acid 1 and applied to the one-pot three-component Kabachnik–Fields reaction. Catalyst 3c was found to be an efficient organocatalyst for the reaction of 2-cyclopropylpyrimidin-4-carbaldehyde 4,various amines 5, and diphenylphosphite 6 to yield the corresponding enantioselective a-aminophosphonates 7a–e in 74%–82% yields and 14%–35% ee.     

Synthesis of highly substituted ureas and thioureas through 1,3-diaza-Claisen rearrangements

Isocyanates and isothiocyanates that are not activated by an electron withdrawing group react with azanorbornenes in benzene at reflux to afford ureas and thioureas through the corresponding 1,3-diaza-Claisen rearrangements. At higher temperatures, a triazinone byproduct is observed. Isocyanates and isothiocyanates that are activated by an electron-withdrawing group react at room temperature to give the corresponding ureas and thioureas. The reactions of the activated isocyanates and isothiocyanates are also accompanied by the formation of isoureas and isothioureas. Interestingly, while benzoyl isocyanate reacts with N-benzyl azanorbornene at room temperature to give a 2:1 mixture of urea to isourea, in benzene at reflux the only product observed is the urea. A crossover experiment rules out the possibility that the products are formed through a retro-Diels-Alder, [4+2] cycloaddition sequence instead of a 1,3-diaza-Claisen rearrangement. Competition experiments between isocyanates and isothiocyanates with limiting azanorbornene indicate that isothiocyanates react faster to give the rearrangement product. Since isocyanates are shown to be more electrophilic, these data are consistent with a fast addition step and a rate-determining rearrangement step.     

Synthesis and complexation of a novel cyclophane

A novel cyclophane, 17, 17, 40, 40-tetramethyl-7, 30-dinitro-1, 10, 24, 33-tetraoxa[2.2.1.2.2.1] metaparaparametaparaparacyclophane, was synthesized by 2:2 cyclization of 3,5-bis(bromomethyl)nitrobenzene, derived from 3,5-dimethylnitrobenzene, and bisphenol A. The cyclophane was found to form 1:1 complex with benzene.     

Capillary complexation gas chromatography in analysis of cyclic and aromatic hydrocarbons

Summary Results of studies on stationary phases containing copper(II), nickel(II) and cobalt(II) chloride chemically bonded via cyano—or thiol groups are presented. The retention parameters—i.e. retention factor (k), retention index (I) and molecular retention index (ΔMe) and specific retention volume (Vg)-enabled the characteristics of specific interaction between aromatic and cyclic hydrocarbons and metal complexes chemically bonded to stationary phases to be determined. Presented at Balaton Symposium on High Performance Separation Methods, Siófok, Hungary, September 1–3, 1999     

Synthesis and characterization of mercury(II)–sugar thioureas complexes

The synthesis of a novel class of mercury(II) complexes with sugar-derived bidentade isothioureido ligands, by treatment of N-acylated thioureas with an excess of yellow mercury(II) oxide in aqueous acetonitrile is reported. The 1:2 coordination stoichiometry of the complexes were confirmed by elemental analysis, mass spectrometry and NMR spectroscopy, and they were found to be consistent with a four-coordinate geometry.     

Synthesis and cation complexation properties of new macrolides

The cis-2-alkyl-3-oxy-tetrahydropyran unit as a novel structure for the design and synthesis of a new type of ionophores with C₂-symmetry is reported. The synthesis of seven different macrolides and a crown ether and their cation complexation properties were investigated. The X-ray crystal structure of some of the receptors provides valuable information on the preferred conformation of tetrahydropyrans in the solid state that can be related to the cation complexation properties in solution. The kinetic template effect has been proved to be a useful tool to improve the yield and selectivity in the synthesis of macrodiolide 3.     

Synthesis and complexation of two new phenylaminoglyoxime ligands

Two new soluble phenylaminoglyoxime ligands, 4-isopropylanilinephenylglyoxime (L¹H₂), 4-benzylpiperidinephenylglyoxime (L²H₂), were prepared by reacting 4-isopropylaniline and 4-benzylpiperidine with chlorophenylglyoxime. Mononuclear nickel(II), cobalt(II), copper(II), zinc(II), and cadmium(II) complexes with these ligands were synthesized. On the basis of the magnetic and spectral evidence a square-planar geometry for Ni(II) and Cu(II) complexes, a tedrahedral geometry for Cd(II) and Zn(II) complexes and octahedral geometry for Co(II) complexes are proposed. These compounds were elucidated by elemental analysis, IR, UV-Vis, and magnetic moments. The ligands were additionally characterized by ¹H NMR and ¹³C NMR spectra.     

Synthesis and complexation of 1,4,7-oxadithiononane-5,6-dionedioxime

A new vic-dioxime 1,4,7-oxadithiononane-5,6-dionedioxime (H₂L) was prepared from reaction of 2,2-oxydiethanthiol with dichloroglyoxime. Mononuclear complexes of H₂L with Ni(II), Co(II), Cu(II), Zn(II), and Cd(II) were also prepared and their structures were determined by means of ¹H?NMR, ¹³C?NMR, IR, and mass spectroscopy. Ni(II), Co(II), and Cu(II) form square planar complexes of 1?:?2 molar ratio of metal to ligand through N,N-chelation, while Zn(II) and Cd(II) form 1?:?1 tetrahedral complexes with a N,O-chelation.     

Novel polyamides with acyclic and cyclic bipyridinediyl diamino structures in the polymer backbone: Synthesis and complexation with transition metals

The synthesis of two novel polyamide ligands 3 and 4 , containing 2,17-diaza[3.3](6,6′)-2,2′-bipyridinophane or 6,6′-bis(2-picolylaminomethyl)-2,2′-bipyridine units as part of the polymer backbone, respectively, and of the appropriate diamide model compounds 1c and 2c is described. ¹H-NMR and IR spectral data support the ligand structures; furthermore, ¹H-VTNMR analysis on macrocyclic diamide 1c indicates a restricted rotation of the amide bonds at ambient temperature and suggests for this molecule a fixed syn conformation in solution, with a “face to face” arrangement of the dipyridinyl moieties. Model compound 2c and polyamide 4 form stable 1:1 complexes with transition metals Co(II), Ni(II), and Cu(II). Conversely, macrocyclic model 1c and polyamide 3 exhibit the unique property to specifically complex Cu(II), even in the presence of sizeable amounts of Co(II) and Ni(II). The IR spectral changes related to the ligands upon complexation are briefly discussed.     

N-苯甲酰基-N’-1,3,4-噻二唑-2-基硫脲的合成及生物活性研究

本文以苯甲酸为原料,经酰氯化、酰化反应得到中间体苯甲酰基异硫氰酸酯,再与2-氨基-1,3,4-噻二唑经加成反应合成并表征了10种N-苯甲酰基-N’-1,3,4-噻二唑-2-基硫脲3a-3j。初步生物活性测试结果表明:当浓度为10 mg/L时,3a～3d对小麦生根和发芽有一定的调节活性。当浓度为100 mg/L时,大部分化合物对黄瓜灰霉病菌、黄瓜炭疽病菌、水稻纹枯病菌、水稻稻瘟病菌有明显的抑制活性,而对棉花枯萎病菌的抑制活性较差。目标化合物的取代基会影响其生长调节活性和抑菌活性。结合量化计算结果讨论了化合物结构对抑菌活性的影响。     

Synthesis,structure and complexation of biscrown-containing 1,4-distyrylbenzenes

An improved method for the synthesis of two symmetric biscrown-containing and one model tetramethoxy-substituted 1,4-distyrylbenzenes was suggested. The structures of compounds were established by ¹H and ¹³C NMR spectroscopy and X-ray diffraction analysis. Spectrophotometric and fluorescent titration were used to determine spectral properties, stoichiometry, and stability of complexes of biscrown-containing 1,4-distyrylbenzenes with alkali and alkaline-earth metal cations. The stability of the complexes was found to depend on the metal cation size and charge, as well as on the size of the crown ether fragment. The electrochemical oxidation and reduction potentials of the biscrown-containing 1,4-distyrylbenzenes and the model compound in solution were determined and their basic differences from the corresponding characteristics of biscrown-containing stilbenes were identified.     

Synthesis and metal ion complexation studies of proton-ionizable calix

A series of novel N-chromogenic calix[4]arene azacrown ethers were synthesized as selective extractants of potassium ion. 1,3-Alternate calix[4]arene azacrown ethers were prepared by reacting 25,27-dipropyloxy-26,28-bis(5-chloro-3-oxapentyloxy) calix[4]arenes with p-toluenesulfonamide in the presence of potassium carbonate. The coupling reaction of calix[4]arene azacrown ether with 2-hydroxy-5-nitrobenzyl bromide in the presence of triethylamine in THF gave the chromogenic calix[4]arene azacrown ether in moderate yield. These compounds show high potassium selectivity over other metal ions as shown by two-phase extraction, bulk liquid membrane, and 1H NMR studies on a ligand-metal complex. It is assumed that the OH of the chromogenic group attached on nitrogen can assist the complexation by encapsulation of the metal.