Spectrophotometric determination of manganese with derivatives of 1,3,3-trimethyl-2-[3-(1,3,3-trimethyl-1,3- H-indol-2-ylidene)propenyl]-3 H-indolium

A new, simple, rapid, and sensitive spectrophotometric method has been developed for the determination of manganese in sewage. The method is based on the reaction of manganese with derivatives of 1,3,3-trimethyl-2-[3-(1,3,3-trimethyl-1,3-H-indol-2-ylidene)propenyl]-3H-indolium to form a colored ion associate with a sensitive absorption maximum at 560 nm. The appropriate reaction conditions have been established: pH 8.5–10.0, 1.25–2.3×10^–3 mol L^–1 1-nitroso-2-naphthol, and 1.6–2.4×10^–4 mol L^–1 dye reagent. Beer's law is obeyed for manganese concentrations up to 4.2 mg L^–1. The limit of detection is 0.01 mg L^–1 Mn²⁺; the molar absorptivity of the ion associate was 7.5×10⁴ L mol^–1 cm^–1. The effect of various foreign ions was examined. A reaction mechanism is suggested. The developed procedure was tested for determination of manganese in sewage with satisfactory precision and accuracy.     

Condensation of 1,2,5-trimethyl-4-piperidone with ethyl- and naphthylacetylenes and synthesis of substituted pyridines

The Favorskii reaction with 1,2,5-trimethyl-4-piperidone and ethyl- and naphthylacetylenes gave the corresponding piperidols, the hydrogenation of which gave 1,2,5-trimethyl-4-nbutyl(or 2-naphthylethyl)-4-piperidols. 4-Phenyl- and 4-butyl-2,5-dimethylpyridine were condensed with formaldehyde, and some of the transformations of the resulting-hydroxyethyl derivatives were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 349–352, March, 1973.     

Synthesis and three-dimensional structures of geometrical isomers of some 4-substitute d 1,2,5-trimethyl-4-acetoxy- and 1,2,5-trimethyl-4-benzoxypiperidines

Stereoisomers of the corresponding 4-substituted 1,2,5-trimethyl-4-acetoxy- and 1,2,5-trimethyl-4-benzoxypiperidines were obtained by acylation of the geometrical isomers of 1,2, 5-trimethyl-4-piperidol and its 4-ethynyl, 4-ethyl, and 4-phenyl-substituted derivatives. The preferred conformations of the investigated esters were elucidated by means of the PMR and IR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No.1, pp. 50–55, January, 1973.     

1H and 13C NMR spectra and three-dimensional structures of 1,2,5-trimethyl-4-phenylaminopiperidine isomers

The three-dimensional structures of two isomers of 1,2,5-trimethyl-4-phenylaminopiperidine were established on the basis of an analysis of their ¹H and ¹³C NMR spectra. The piperidine ring has a chair conformation in both isomers. The isomer has the 1,2e,5a, trimethyl-4e-phenylaminopiperidine structure, while the isomer has the 1,2e,5e-trimethyl-4e-phenylaminopiperidine structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1512–1515, November, 1982.     

Peculiarities of the three-dimensional structures of isomers of 1,2,5-trimethyl-4-amino(amido)piperidines from the 1H and 13C NMR spectra

The three-dimensional structures of seven 1,2,5-trimethyl-4-amino(amido)piperidines were studied by means of the ¹H and ¹³C NMR spectra. The ³J_HH values and the ¹³C chemical shifts indicate that the substituents in the piperidine ring of all of the 2c,5c,4r isomers have a 2e,4e,5a orientation, while those in the piperidine ring of all of the 2c,5t,4r isomers have a 2e,4e,5e orientation. The conformational change (as a result of ring conversion) 2e,4a,5e 2a,4e,5a was observed for the 2t,5c,4r isomers on passing from the corresponding amine to the amide; this change is associated with striving of the more bulky amide substituent to become equatorially oriented. Retarded rotation about the C₍₄₎-N bond was observed in the 2c,5t,4r isomer of the 4-(N-phenylbenzamido) derivative; this is explained by steric hindrance due to the 5e-CH₃ group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 54–57, January, 1988.The authors thank I. I. Chervin for assistance in recording the NMR spectra with a WM-400 spectrometer.     

1,2,5-Trimethyl-4-(p-hydroxyaryl)-δ3-tetrahydropyridines and their spatial structure

The condensation of 1,2,5-trimethylpiperidine-4-one with phenol and isomeric cresols yields 1,2,5-trimethyl-4-(p-hydroxyphenyl)- and (p-hydroxytolyl)-³-tetrahydropyridines, the structure and conformation of which have been studied by proton NMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1367–1370, October, 1986.     

Reaction ofβ,β -dimethyldivinyl ketone with 2,5-dimethyl- and 1,2,5-trimethyl-4-piperidones

1-(3-Oxo-5-methyl-4-hexen-1-yl)-2,5-dimethyl-4-piperidone, 5-(3-oxo-5-methyl-4-hexen-1-yl)-2, 5-dimethyl-4-piperidone, and 5-(3-oxo-5-methyl-4-hexen-1-yl)-1,2,5-trimethyl-4-piperidone were synthesized. In the absence of a catalyst,-dimethyldivinyl ketone adds to 2,5-dimethyl-4-piperidone at the 1-position, while in the presence of alkali it adds at the 5-position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 350–351, March, 1971.     

New Bifunctional Bis(azairidacycle) with Axial Chirality via Double Cyclometalation of 2,2′-Bis(aminomethyl)-1,1′-binaphthyl

As a candidate for bifunctional asymmetric catalysts containing a half-sandwich C–N chelating Ir(III) framework (azairidacycle), a dinuclear Ir complex with an axially chiral linkage is newly designed. An expedient synthesis of chiral 2,2′-bis(aminomethyl)-1,1′-binaphthyl (1) from 1,1-bi-2-naphthol (BINOL) was accomplished by a three-step process involving nickel-catalyzed cyanation and subsequent reduction with Raney-Ni and KBH₄. The reaction of (S)-1 with an equimolar amount of [IrCl₂Cp*]₂ (Cp* = η⁵–C₅(CH₃)₅) in the presence of sodium acetate in acetonitrile at 80 °C gave a diastereomeric mixture of new dinuclear dichloridodiiridium complexes (5) through the double C–H bond cleavage, as confirmed by ¹H NMR spectroscopy. A loss of the central chirality on the Ir centers of 5 was demonstrated by treatment with KOC(CH₃)₃ to generate the corresponding 16e amidoiridium complex 6. The following hydrogen transfer from 2-propanol to 6 provided diastereomers of hydrido(amine)iridium retaining the bis(azairidacycle) architecture. The dinuclear chlorido(amine)iridium 5 can serve as a catalyst precursor for the asymmetric transfer hydrogenation of acetophenone with a substrate to a catalyst ratio of 200 in the presence of KOC(CH₃)₃ in 2-propanol, leading to (S)-1-phenylethanol with up to an enantiomeric excess (ee) of 67%.     

1H and 13C NMR spectra,isomers, and imine-enamine tautomers of N-(1,2,5-trimethyl-4-piperidylidene)aniline

The product of condensing 1,2,5-trimethylpiperidin-4-one with aniline has been investigated by NMR spectroscopy. Three isomers of N-(1,2,5-trimethyl-4-piperidylidene)aniline have been identified differing in the configuration of the methyl groups at C₂ and C₅ of the piperidine ring and the Z,E isomerism about the C=N bond. Traces of the enamine tautomeric form of the imine were also detected. , , and spin-spin couplings were used to determine the structural configuration of the isomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1405–1408, October, 1989.     

Buffer Standards for the Physiological pH of Zwitterionic Compounds,MOBS and TABS from 5 to 55°C

The values of the second dissociation constant, pK₂, and related thermodynamic quantities of 4-(N-morpholino)butanesulfonic acid (MOBS) and N-tris(hydroxymethyl)-4-aminobutanesulfonic acid (TABS) have already been reported over the temperature range 5–55°C including 37{°}C. This paper reports the pH values of twelve equimolal buffer solutions at designated pH (s) with the following compositions: (a) mixtures of MOBS (0.05 mol-kg^–1) + NaMOBS (0.05 mol-kg^–1); (b) MOBS (0.08 mol-kg^–1) + NaMOBS (0.08 mol-kg^–1); (c) MOBS (0.08 mol-kg^–1) + NaMOBS (0.08 mol-kg^–1) + NaCl (0.08 mol-kg^–1); (d) TABS (0.05 mol-kg^–1) + NaTABS (0.05 mol-kg^–1); and (e) TABS (0.08 mol-kg^–1) + NaTABS (0.08 mol-kg^–1); and (f) TABS (0.08 mol-kg^–1) + NaTABS (0.08 mol-kg^–1) + NaCl (0.08 mol-kg^–1). Two buffer solutions have ionic strengths I= 0.05 mol-kg^–1, another two have I=0.08 mol-kg^–1, and the remaining two buffer solutions have I= 0.16 mol-kg^–1, which is close to that of the clinical fluids (blood serum). These buffers have been recommended as a useful pH standard for the measurements of physiological solutions. Conventional pH values of all six buffer solutions from 5–55°C, as well as those obtained from the liquid junction potential correction at 25 and 37{°}C have been calculated. The flowing-junction calomel cell has been utilized to measure E_j, the liquid junction potential.     

Tin(IV) and organotin(IV) derivatives of novel β-diketones: Part IV. Triorganotin(IV) complexes of fluorinated 4-acyl-5-pyrazolones. Crystal structure of (1-(4-trifluoromethylphenyl)-3-methyl-4-acetylpyrazolon-5-ato)triphenyltin(IV)

The synthesis of three 1-(4-trifluoromethylphenyl)-3-methyl-4-R¹(C=O)-5-pyrazolone proligands LH (L¹H; R¹=C₆H₅: L²H; R¹=CH₃: L³H; R¹=CF₃) and their interaction with R₃Sn(IV) acceptors (R=Me, Buⁿ, Ph) are reported. When R=Me or Buⁿ, aquo (4-acylpyrazolonate)SnR₃(H₂O) derivatives are obtained and the anionic donors 4-acylpyrazolonate (L⁻) act in the O–monodentate form. These triorganotin complexes are not stable in chlorohydrocarbon solvents and decompose to R₄Sn and bis(4-acyl-5-pyrazolonate)₂SnR₂. When R=Ph, stable (4-acyl-5-pyrazolonate)SnPh₃ derivatives, both in solution and in the solid state, are obtained. The crystal structure of (1-(4-trifluoromethylphenyl)-3-methyl-4-acetylpyrazolon-5-ato)triphenyltin(IV) shows a five-coordinate tin atom in a strongly distorted cis-bipyramidal trigonal environment (axial angle=161.2(2)°) with the acylpyrazolonate donor acting as an asymmetric O₂–bidentate species (Sn–O(1)=2.081(6) Å: Sn–O(2)=2.424(5) Å). Electronic effects are responsible for the different behavior shown by these trialkyl and triphenyl derivatives.     

5-甲基-[(2E,6E)-3,7,11-三甲基-9-氧代十二碳二烯]苯醌和氢醌的首次全合成

以2-甲基对苯二酚和香叶基溴为起始原料, 经过酚羟基保护, 溴代, Li₂CuCl₄催化的芳基溴与Grignard试剂的偶联以及Julia偶联等一系列反应, 完成了裸鳃亚动物的代谢产物, 5-甲基-[(2E,6E)-3,7,11-三甲基-9-氧代十二碳二烯]苯醌(1)和氢醌(2)的首次全合成, 将1用NaBH₄还原, 得到(±)-3, (±)-3也是此类天然产物之一.     

Asymmetric synthesis and absolute configuration of 1-α-phenylethyl-2,5-dimethyl-4-piperidone isomers

Reaction of the methyl iodide of trans-1,2,5-trimethyl-4-piperidone with S--phenylethylamine proceeds asymmetrically and leads in 66% optical yield to the formation of the cis- and trans-diastereomeric pair of 1-(-phenylethyl)-2,5-dimethyl-4-piperidone, in which the new asymmetric centers possess the 2S,5S- and 2S,5R-configurations, respectively. According to x-ray structural analysis, the minor trans-1-(-phenylethyl)-2,5-dimethyl-4-piperidone component possesses the 2R,5S-configuration. The occurrence of asymmetric synthesis accompanying transamination was confirmed via the preparation of enantiomers of trans-2,5- and trans-1,2,5-trimethyl-4-piperidones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1641–1648, December, 1986.     

Steric control of the asymmetric synthesis of N-substitued 2-methyl-4-piperidones

Transmission of the iodomethylate of 1,2-dimethyl-4-piperidone by (S)-sec-butylamine gives 1-(S-sec-butyl)-2S-methyl-4-piperidone in 33% optical yield while transamination by (S)-l-methyl-2-phenylethylamine gives a 1:1 diastereomeric mixture of 1-(l-methyl-2-phenylethyl)-2 -methyl-4-piperidone.The decrease in the optical yield is related to the facile opening of the piperidone ring at the C-N bond with subsequent recyclization. The¹³C MIR data indicate that all the diastereomers of the 4-piperidones obtained are in the chair conformation with predominantly equatorial orientation of the methyl group at C₍₂₎. The chiral optical properties were studied and the absolution configurations of the 4-piperidones obtained were established.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1648–1655, December, 1985.     

Metal complexes of C2-symmetric chiral bipyridine ligands. X-ray structure of [bis(nitrato)(4S,5S)-2,2-dimethyl-4,5-bis(2-pyridyl)-1,3-dioxolane cobalt(II)]

Chelating properties of C₂-symmetric chiral bipyridine ligands are discussed. In particular we report the syntheses of the cobalt(II), nickel(II), zinc(II) and copper(II) complexes of (4S,5S)-2,2-dimethyl-4,5-bis(2-pyridyl)-1,3-dioxolane. All compounds have been characterized by IR spectroscopy, and an X-ray diffraction analysis has been carried out on one of them: Co(L)(NO₃)₂. The ligand coordinates the cobalt atom by the two nitrogen donors N(1) and N(2). A seven-membered chelation ring is formed, presenting a remarkable non-crystallographic twofold pseudosymmetry around the axis connecting Co and the midpoint of the C(6)–C(7) bond. The metal also binds two monodentate nitrates, thus completing a distorted coordination tetrahedron.     

Spektralphotometrische Bestimmung von Kobalt mit 2-(5-Brom-2-pyridylazo)-5-Diethylaminophenol

Zusammenfassung Eine empfindliche und selektive spektralphotometrische Kobaltbestimmung (<0,9 g ml^–1) ist mit 2-(5-Brom-2-pyridylazo)-5-diethylaminophenol (5-Brom-PADAP) auf Grund des kinetisch stabilen Co(III)L ₂ ^– -Chelates möglich, das nach seiner Bildung bei pH 7 (Ammoniumacetat) in Gegenwart von 0,1% Triton X-100, 5,10^–3 M Ammoniumperoxodisulfat und 10% (v/v) Dimethylformamid (auch nach Zugabe von 1,25 M H₂SO₄, 1,80 M HNO₃ oder auch 0,1–0,01 M EDTA) stabil ist. Eine Reihe von 5-Brom-PADAP-Chelaten störender Ionen werden dabei zersetzt. V(V), Hg²⁺, Ni²⁺, Cu²⁺, Pd²⁺ können stören. Die Kobaltbestimmung in Cyanocobalamin und auch Trinkwasser ist auf diesem Wege möglich. Die Fehler lagen im Bereich von — 3 bis — 7 % (1,8–9 g Co/l).Herrn Prof. Dr. F. Umland, Westfälische Universität, Münster/Westfalen, sind wir für das 5-Brom-PADAP mit herzlichem Dank verpflichtet.     

Investigation of 2-[(<Emphasis Type="Italic">E</Emphasis>)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3H-indolium as a new highly sensitive reagent for the spectrophotometric determination of nitrophenols

A new, simple, rapid, and sensitive spectrophotometric method has been developed for the determination of nitrophenols [picric acid (PA); dinitrophenols (DNP)] in wastewater samples. The method is based on the reaction of nitrophenols with 2-[(E)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3 H-indolium chloride reagent to form the colored ion associates, which are extracted by organic solvents. The molar absorptivity of the ion associates of PA with the investigated reagent ranges from 8.3×10⁴ to 11.3×10⁴ L mol^–1 cm^–1, depending on the extractant. Because only PA is extracted in an acidic medium with the investigated reagent, but both PA and DNP are extracted in an alkaline medium, it is possible to determine both substances in a mixture. Appropriate reaction conditions have been established. The absorbance of the colored extracts obeys Beers law in the range of 0.04–4.58 mg L^–1 PA, 1.0–18.4 mg L^–1 2,4-DNP and 1.2–14.7 mg L^–1 2,6-DNP, respectively. The limit of detections, calculated from a blank test (n=10; P=0.95), are 0.05 mg L^–1 PA, 0.9 mg L^–1 (2,4-DNP), and 1.1 mg L^–1 (2,6-DNP), respectively.     

Synthetic and kinetic studies on copper(II), nickel(II) and cobalt(III) complexes of 1,4,7,10,13-pentaazacyclohexadecane ([16]aneN5)

Summary The pentadentate macrocycle 1,4,7,10,13-penta-azacyclo-hexadecane [16]aneN₅=(3)=L} has been prepared and a variety of copper(II), nickel(II) and cobalt(III) complexes of the ligand characterised. The copper complex [CuL](ClO₄)₂, on the basis of its d-d spectrum, appears to be square pyramidal, while [NiL(H₂O)](ClO₄)₂ is octahedral. The copper(II) and nickel(II) complexes dissociate readily in acidic solution and these reactions have been studied kinetically. For the copper(II) complex, rate=k_H[complex][H⁺]² with k_H =4.8 dm⁶ mol^–2s^–1 at 25 °C and I=1.0 mol dm^–3 (NaClO₄) with H=43 kJ mol^–1 and S ₂₉₈ =–89 JK^–1 mol^–1. Dissociation rates of the copper(II) complexes increase with ring size in the order: [15]aneN₅ < [16]aneN₅ < [17]aneN₅. For the dissociation of the nickel(II) complex, rate=k_H[Complex][H⁺] with k_H=9.4×10^–3 dm³mol^–1 s^–1 at 25 °C and I =1.0 mol dm^–3 (NaClO₄) with H=71 kJ mol^–1 and S ₂₉₈ =–47 JK^–1mol^–1.The cobalt(III) complexes, [CoLCl](ClO₄)₂, [CoL(H₂O)]-(ClO₄)₃, [CoL(NO₂)](ClO₄)₂, [CoL(DMF)](ClO₄)₃ (DMF=dimethylformamide) and [CoL(O₂CH)](ClO₄)₂ have been characterised. The chloropentamine [CoCl([16]aneN₅)]²⁺ undergoes rapid base hydrolysis with k_OH=1.1× 10⁵dm³ mol^–1s^–1 at 25°C and I=0.1 mol dm^–3 (H=73 kJ mol^–1 and S ₂₉₈ =98 JK^–1 mol^–1). Rapid base hydrolysis of [CoL(NO₂)]²⁺ is also observed and the origins of these effects are considered in detail.     

13C NMR spectra of the bases and conjugate acids of 3- and 5-formyl-,acetyl-, and carbethoxypyrroles

The effect of protonation of the oxygen atom of the carbonyl group and the carbon atom of the pyrrole ring on the ¹³C chemical shifts in a series of 3- and 5-formyl-, 3-acetyl-, and 3-carbethoxypyrroles was studied. The structures of the conjugate acids of the 5-carbethoxypyrroles was established on the basis of measurement of the ¹H and ¹³C NMR spectra. It is shown that protonation of the 5-carbethoxypyr roles occurs at the ring 5-C atom in 28–35 N H₂SO₄. The effect of structural factors and the acidity of the medium on the relative stabilities of the CH conjugate acids of the investigated compounds is examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 485–492, April, 1979.     

The preparation and characterisation of chromium(III) complexes of C-meso-5, 12-dimethyl-1, 4, 8, 11-tetraazacyclotetradecane (LM). Aquation and base hydrolysis kinetics ofcis- andtrans-[CrLMCl2]+

Summary The reaction of [CrCl₃(DMF)₃] with C-meso-5, 12-dimethyl-1, 4, 8, 11-tetra-azacyclotetradecane(L_M) in DMF gives a mixture ofcis-[CrL_MCl₂]Cl (ca. 90%) andtrans-[CrL_MCl₂]Cl (ca. 10%). These complexes are readily separated, as thecis-isomer is insoluble in warm methanol while thetrans-isomer is soluble. Using the dichlorocomplexes as precursors it has been possible to prepare a range ofcis-[CrL_MX₂]⁺ complexes (X=Br^–, NO ₃ ^– , N ₃ ^– , NCS^– and X₂=bidentate oxalate) and alsotrans-[CrL_MX₂]⁺ complexes (X=Br^–, H₂O or NCS^–). The spectroscopic properties and detailed stereochemistry of the complexes are discussed.The aquation and base hydrolysis kinetics ofcis- andtrans-[CrL_MCl₂]⁺ have been studied at 25° C. Base hydrolysis of thecis-complex is extremely rapid with K_OH =1.46×10⁵ dm³ mol^–1 at 25° C. This unusual reactivity appears to be associated with thetrans II stereochemistry of thesec-NH centres of the macrocycle. Base hydrolysis of thetrans complex with thetrans III chiral nitrogen stereochemistry is quite normal with k_OH =1.1 dm³ mol^–1 s^–1 at 25° C.