Determination of thermodynamic parameters and equilibrium constants for complexation reactions involving lanthanon(III) ions with 1,2-naphthoquinone-2-semicarbazone-4-sulphonic acid (sodium salt) (NQS · 4S)

The thermodynamic parameters and equilibrium constants of complexation reactions of 1,2-naphthoquinone-2-semicarbazone-4-sulphonic acid (sodium salt) (NQS · 4S) involving lanthanon ions were evaluated by potentiometric estimation of [H⁺], in aqueous medium at various ionic strengths (0.02, 0.05, 0.10 and 0.20 M NaClO₄) and at different temperatures (20, 30, 40 and 50±0.5°C). The −n and pL values calculated by the method of Bjerrum and Calvin, as modified by Irving and Rossotti, were used for the calculation of the equilibrium constants on an HCL Busy Bee PC/AT computer using the weighted least-squares method. The values of S_min were also evaluated. The order of equilibrium constants was found to be Ho(III) > Dy(III) > Tb(III) > Y(III) > Eu(III) > Sm(III) > Gd(III) > Nd(III) > Pr(III) > Ce(III) > La(III). The thermodynamic parameters ΔG, ΔH and ΔS were also calculated at a fixed temperature (30±0.05°C) and ionic strength (0.10 M NaClO₄).     

Spectrophotometric determination of aminomethylbenzoic acid using sodium 1,2-naphthoquinone-4-sulfonate as the chemical derivative chromogenic reagent

A new method has been established for the determination of aminomethylbenzoic acid using sodium 1,2-naphthoquinone-4-sulfonate as the chemical derivative chromogenic reagent. This method is based on the formation of a pink compound from the reaction of aminomethylbenzoic acid and sodium 1,2-naphthoquinone-4-sulfonate. The nucleophilic substitution reaction proceeds quantitatively in pH 12.0 buffer solution. The stoichiometric ratio of the reaction, maximum absorption wavelength and the value of epsilon(430) were 1:1, 430 nm, and 2.87 x 10(3)L mol(-1)cm(-1), respectively. Beer's law was obeyed in the range of 0.80-80 mg/L of aminomethylbenzoic acid. The data have been filled to a linear regression equation A=0.03183+0.01658C (mg/L), with a correlation coefficient of 0.9996. The detection limit is 0.11 mg/L, R.S.D. is 0.54%, and average recovery is over 99.6%. This paper further improves the determination of aminomethylbenzoic acid compared to the previous methods. The kinetic property and reaction mechanism have also been discussed. This proposed method has been successfully applied to the determination of aminomethylbenzoic acid in injection of aminomethylbenzoic acid with satisfactory results.     

Reaction of some sympathomimetic amines with sodium 1,2-naphthoquinone-4-sulphonate

Summary The condensation products of 4 sympathomimetic amines with 1,2-naphthoquinone-4-sulphonic acid have been prepared and examined. A spectrophotometric procedure based on the chloroform-soluble orange-red condensation product is described. The same products were investigated fluorimetrically after reduction with sodium borohydride. The results obtained are satisfactory.

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Zusammenfassung Die Kondensationsprodukte vier sympathicomimetischer Amine mit 1,2-Naphthochinon-4-sulfonsäure wurden dargestellt und untersucht. Ein spektralphotometrisches Verfahren auf der Grundlage des chloroformlöslichen, orangeroten Kondensationsproduktes wurde beschrieben. Die gleichen Produkte wurden auch fluoreszenzanalytisch nach ihrer Reduktion mit Natriumborhydrid untersucht. Die Ergebnisse sind befriedigend.

     

Synthesis and Structure of Biologically Active 1,2-Bis(2-oxocycloalkyl)ethane-1,2-diones and 3,4-Dioxo-4-(2-oxocycloalkyl)butanoic Acid Esters

Russian Journal of General Chemistry - A two-step procedure has been proposed for the synthesis of 1,2-bis(2-oxocycloalkyl)ethane-1,2-diones and 3,4-dioxo-4-(2-oxocycloalkyl)butanoic acid esters by...     

Esters of (1,2, 5-trimethyl-4-hydroxy-4-piperedyl)- and phenyl-(1,2, 5-trimethyl-4-hydroxy-4-piperidyl) acetic acids

The methyl ester of a new hydroxy acid of the piperidine series (-phenyl--(1,2, 5-trimethyl-4-hydroxy 4-piperidyl)acetic acid) has been prepared. Ethyl -(1,2, 5-trimethyl-4-hydroxy-4-piperidyl)acetate has been converted into the substituted pyridine, 1,1-diphenyl-2-(2-5-dimethyl-4-pyridyl)ethylene.     

The preparation,spectra and tautomerism of some 4(n-arylamino)-1,2-naphthoquinones

Twelve 4(N-arylamino)-1,2-naphthoquinones (1) have been prepared by the direct addition of substituted anilines to 1,2-naphthoquinone, and their spectra have been studied. In the solid and in ethanol solution the 1,2-naphthoquinone tautomer (1a) predominates, but in trifluoroacetic acid the 2-hydroxy-1,4-naphthoquinone-4-aryliminium (2a) is the major species.     

4-Hydroxy-2-quinolones. 168*. Synthesis,chemical and antitubercular properties of 1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid pyrazin-2-ylamides

1-R-4-Hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid pyrazin-2-ylamides have been synthesized as potential antitubercular agents. In contrast to pyrimidin-2-ylamides the compounds prepared are brominated by molecular bromine in glacial acetic acid at position 6 of the quinolone ring rather than in the amide part of the molecule. The 1-N-allyl derivative behaves similarly but undergoes halocyclization to give 2-bromomethyl-5-oxo-1,2-dihydro-5H-oxazolo[3,2-a]quinoline-4-carboxylic acid pyrazin-2-ylamide. A comparative analysis of the antimycobacterial properties of the synthesized compounds and their isomeric pyrimidin-2-ylamides has been carried out.     

Synthesis of 4-R-2,2-dimethyl-1,2-dihydrobenzo[f]isoquinolines and (2,2-dimethyl-1,2-dihydrobenzo[f]isoquinolylidene-4)acetic acid derivatives

4-R-2,2-dimethyl-1,2-dihydrobenzo[f]isoquinolines and (2,2-dimethyl-1,2-dihydrobenzo[f]isoquinolylidene-4)acetic acid derivatives have been prepared by Ritter reactions of substituted acetonitriles with 2-methyl-1-(1-naphthyl)propan-2-ol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 375–376, March, 1992.     

4-hydroxy-2-quinolones. 202*. Synthesis, chemical and biological properties of 4-hydroxy-6,7-dimethoxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid alkylamides

In continuation of the search for potential analgesics amongst 4-hydroxyquinol-2-one derivatives we have proposed and carried out a preparative method of synthesis of 4-hydroxy-6,7-dimethoxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid alkylamides. It has been shown that bromination of 4-hydroxy-6,7-dimethoxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid allylamide using an equivalent of molecular bromine occurs with a conventional addition of the halogen to the allyl double bond and not with halocyclization. The results of the study of the analgesic properties of the compounds prepared are presented.     

4-hydroxy-2-quinolones. 179*. Synthesis,structure, and anti-inflammatory activity of 4-hydroxy-1-methyl-2-oxo-1,2-dihydroquinolin-3-ylacetic acid and its derivatives

The synthesis of 4-hydroxy-1-methyl-2-oxo-1,2-dihydroquinolin-3-ylacetic acid has been carried out and the structure and acid properties studied. Preparative methods for its esterification and amidation are proposed. The anti-inflammatory properties of the synthesized compounds have been evaluated.     

Sulfido-bridged dinuclear molybdenum-copper complexes related to the active site of CO dehydrogenase: [(dithiolate)Mo(O)S2Cu(SAr)]2- (dithiolate = 1,2-S2C6H4, 1,2-S2C6H2-3,6-Cl2, 1,2-S2C2H4)

The [MoCu] carbon monoxide dehydrogenase (CODH) is a Cu-containing molybdo-flavoprotein, the active site of which contains a pterin-dithiolene cofactor bound to a sulfido-bridged dinuclear Mo-Cu complex. In this paper, the synthesis and characterization of dinuclear Mo-Cu complexes relevant to the active site of [MoCu]-CODH are described. Reaction of [MoO2S2]2- with CuCN affords the dinuclear complex [O2MoS2Cu(CN)]2- (1), in which the CN- ligand can be replaced with various aryl thiolates to give rise to a series of dinuclear complexes [O2MoS2Cu(SAr)]2- (Ar = Ph (2), o-Tol (3), and p-Tol (4)). An alternative synthesis of complex 2 is the reaction of [MoO2S2]2- with [Cu(SPh)3]2-. Similarly, [O2MoS2Cu(PPh3)]- (5), [O2MoS2Cu(dppe)]- (dppe = 1,2-bis(diphenylphosphino)ethane) (6), and [O2MoS2Cu(triphos)]- (triphos = 1,1,1-tris[(diphenylphosphino)methyl]ethane) (7) were prepared from the reactions of [MoO2S2]2- with the Cu(I) phosphine complexes. Treatment of 1, 2, 4, or 5 with dithiols (1,2-(SH)2C6H4, 1,2-(SH)2C6H2-3,6-Cl2, and 1,2-(SH)2C2H4), in acetonitrile, leads to the replacement of a molybdenum-bound oxo ligand to yield [(dithiolate)Mo(O)S2CuL]2- (L = CN, SAr; dithiolate = 1,2-S2C6H4, 1,2-S2C6H2-3,6-Cl2, or 1,2-S2C2H4) (8-13) or [(1,2-S2C6H4)Mo(O)S2Cu(PPh3)]- (14) complexes.     

Über Chalkogenolate. 160. Umsetzung von 1,2-Ethandithiolaten mit Kohlenstoffdisulfid 2. 1,2-Ethan-bis(trithiokohlensäure) und Alkylester der Säure

On Chalcogenolates. 160. Reaction of 1,2-Ethanedithiolates with Carbon Disulfide. 2. 1,2-Ethane-bis(trithiocarbonic acid) and Alkyl Esters of This Acid The reaction of potassium 1,2-ethane-bis(trithiocarbonate) with hydrochloric acid at 0°C gives unstable, deep yellow coloured 1,2-ethane-bis(trithiocarbonic acid) The 1,2-ethane-bis(alkyl trithiocarbonates) RS? CS? SCH₂CH₂S? CS? SR, where R = CH₃ and C₂H₅, have been formed by reaction of potassium 1,2-ethane-bis(trithiocarbonate) with the corresponding alkyl iodide. The called compounds have been characterized by means of diverse spectroscopic methods.     

Synthesis of (2S,3S)-[3-(2)H1]-4-methyleneglutamic acid and (2S,3R)-[2,3-(2)H2]-4-methyleneglutamic acid

(2S,3S)-[3-(2)H1]-4-Methyleneglutamic acid 1a and (2S,3R)-[2,3-(2)H2]-4-methyleneglutamic acid 1b have been synthesised for use in biosynthetic and metabolic studies.     

Kottamide E, the first example of a natural product bearing the amino acid 4-amino-1,2-dithiolane-4-carboxylic acid (Adt)

Kottamide E, a novel alkaloid containing dibrominated indole enamide, oxalic acid diamide and 4-amino-1,2-dithiolane-4-carboxamide moieties, has been isolated from the New Zealand ascidian Pycnoclavella kottae. Characterisation was achieved by interpretation of spectroscopic data.     

4-hydroxy-2-quinolones. 96. Synthesis and properties of 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid

Alkaline hydrolysis of the ethyl ester of 4-(cyanoethoxycarbonylmethyl)-2-oxo-1,2-dihydroquinoline-3-carboxylic acid is accompanied by decarboxylation with loss of two molecules of CO₂ and leads to 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 887–893, June, 2006.     

4-Hydroxy-2-quinolones. 195*. Synthesis of novel,potential analgesics based on 4-(hetarylmethyl)amino-2-oxo-1,2-dihydro-quinoline-3-carboxylic acids

From the viewpoint of the method of bioisosteric replacement we have carried out the synthesis of a series of 4-(hetarylmethyl)amino-2-oxo-1,2-dihydroquinoline-3-carboxylic acids. For several examples it has been shown experimentally that the aromatic ring in the benzyl fragment of 4-benzylamino-2-oxo-1,2-dihydroquinoline-3-carboxylic acid can be replaced by an isosteric heterocycle without lowering the analgesic properties.     

Synthesis of 1,2-di-(4-pyridyl)ethylenediamine and related compounds

Hydrolysis of N,N'-diacyl-1,2-di(4-pyridyl)ethylenediamines 1 in aqueous sulfuric acid gave the corresponding imidazolines 3. 1,2-Di-(4-pyridyl)ethylenediamine 2 was prepared in 61 % yield by treating N,N'-di-t-butyl-oxycarbonyl-1,2-di(4-pyridyl)ethylenediamine 4 with trifluoroacetic acid or in 94% yield by the hydrolysis under basic conditions of N,N'-diphthaloylglycyl-1,2-di(4-pyridy)ethylenediamine 13.     

4-hydroxy-2-quinolones. 110. Bromination of 1-r-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid anilides

1-R-4-Hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid anilides have been prepared. It has been shown experimentally that these compounds are brominated by molecular bromine in glacial acetic acid at position 4 of the anilide fragment. The antitubercular properties of the compounds synthesized are discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1508–1516, October, 2006.     

Synthesis,Crystal Structure and Characterization of a New Tetra-nuclear Lead Complex:[Pb_4(1,2-bdc)_4(L)_2]·2.25H_2O

The title complex,[Pb4(1,2-bdc)4(L)2]·2.25H2O 1(L = 2-(2-chloro-6-fluorophen-yl)-1H-imidazo[4,5-f][1,10]phenanthroline,1,2-H2bdc = 1,2-benzenedicarboxylic acid),has been obtained by using hydrothermal synthesis and characterized by elemental analysis,IR and single-crystal X-ray diffraction.It crystallizes in monoclinic,space group P21/c with a = 12.0920(6),b = 18.9248(10),c = 15.2729(8) ,β = 98.7530(10)°,V = 3454.3(3) 3,Z = 1,C140H90Cl4F4N16O41Pb8,Mr = 4527.60,Dc = 2.176 g/cm3,F(000) = 2130,μ(MoKa) = 9.884 mm-1,R = 0.0241 and wR = 0.0582.Compound 1 exhibits a unique tetra-nuclear structure,and is further stacked by π-π interactions to give a two-dimensional supramolecular layer.The N-H···O and O-H···O hydrogen bonds stabilize the structure of 1.     

Combinatorial solution-phase synthesis of (2S,4S)-4-acylamino-5-oxopyrrolidine-2-carboxamides

Solution-phase combinatorial synthesis of (2S,4S)-4-acylamino-5-oxopyrrolidine-2-carboxamides was studied. First, di-tert-butyl (2S,4S)-4-amino-5-oxopyrrolidine-1,2-dicarboxylate hydrochloride was prepared as the key intermediate in five steps from (S)-pyroglutamic acid. Acylation of the amino group followed by acidolytic deprotection gave (2S,4S)-4-acylamino-5-oxopyrrolidine-2-carboxylic acids, which were then coupled with amines to furnish a library of (2S,4S)-4-acylamino-5-oxopyrrolidine-2-carboxamides. Four coupling reagents, BPC, EEDQ, TBTU, and PFTU, were tested for the amidation reactions in the final step. Amidations with EEDQ and TBTU led to the desired carboxamides. On the other hand, BPC and PFTU were not suited, since diketopiperazines were sometimes obtained instead of the desired carboxamides.