Dissolution Properties of 2-(Dinitromethylene)-5-methyl-1,3-diazacyclopentane in Dimethyl Sulfoxide and N-Methyl Pyrrolidone

The molar enthalpies of dissolution for 2-(dinitromethylene)-5-methyl-1,3-diazacyclopentane(DNMDZ) in dimethyl sulfoxide(DMSO) and N-methyl pyrrolidone(NMP) were measured using an RD496-2000 Calvet microcalorimeter at 298.15 K under atmospheric pressure. Empirical formulae for the calculation of the molar enthalpies of dissolution(Δ_dissH) were obtained from the experimental data of the dissolution processes of DNMDZ in DMSO or NMP. The relationships between the rate constant(k) and the molality(b) and between the reaction order(n) and the molality(b) were determined. The corresponding kinetic equations describing the two dissolution processes were dα/dt=10^-2.16(1-α)^1.01 for the dissolution of DNMDZ in DMSO, and dα/dt=10^-2.02(1-α)^0.85 for the dissolution of DNMDZ in NMP, respectively.     

Synthesis of 4-Hydroxy- and 4-Amino-2-Methyl-3-(2-Methylindol-3-Yl)methylquinolines and Their 6- and 8-Substituted Derivatives

A method has been developed for the synthesis of substituted 4-hydroxy- and 4-amino-2-methyl-3-(2-methylindol-3-yl)methylquinolines by treating the corresponding 4-hydroxy(chloro)-2-methyl-3-(3-oxobutyl)quinolines with phenylhydrazine hydrochloride. It was found that nucleophilic substitution occurred in the case of the 4-chloroquinolines together with subsequent rearrangement to give the 4-amino derivatives. The thiosemicarbazones of the corresponding 4-hydroxy-2-methyl-3-(3-oxobutyl)quinolines were also obtained.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 554–557, April, 2005.     

A simple and convenient synthesis of 2-(perfluoroalkyl)-4H-chromenes from salicyl N-tosylimines or salicylaldehydes and methyl 2-perfluoroalkynoates

Et₃N-catalyzed reactions of salicyl N-tosylimines or salicylaldehydes with methyl 2-perfluoroalkynoates proceed smoothly at room temperature in dichloromethane (DCM) or dimethyl sulfoxide (DMSO) to give the corresponding fluorinated chromenes in good to excellent yields with high regioselectivity.     

Synthesis, characterization and antifungal activity of group 12 metal complexes of 2-acetylpyridine-N-ethylthiosemicarbazone (H4EL) and 2-acetylpyridine-N-oxide-N-ethylthiosemicarbazone (H4ELO)

Reaction of group 12 metal halides in ethanol with the thiosemicarbazones 2-acetylpyridine-⁴N-ethylthiosemicarbazone (H4EL) and 2-acetylpyridine-N-oxide-⁴N-ethylthiosemicarbazone (H4ELO) produced the compounds [M(H4EL)X₂] and [M(H4ELO)X₂] [M=Zn(II), Cd(II) or Hg(II), X=Cl, Br or I]. The ligands and complexes were characterized by elemental analysis and by IR and NMR (¹H, ¹³C, ¹¹³Cd, ¹⁹⁹Hg) spectroscopy, and the structures of H4ELO·H₂O and the complexes [Cd(H4EL)I₂]·2DMSO, [Hg(H4EL)Br₂]–DMSO, [Zn(H4ELO)Cl₂] and [Zn(H4ELO)Br₂] were determined by X-ray diffraction. The metal centers in the complexes have coordination number five, H4EL and H4ELO behaving as neutral NNS- and ONS-tridentate ligands, respectively. The coordination polyhedra are close to tetragonal pyramids, the degree of distortion towards trigonal bipyramids was estimated by τ calculation. Against the pathogenic fungi Aspergillus niger and Paecilomyces variotii, the mercury complexes of H4ELO had activities that at some doses exceeded that of nystatin.     

Reactivity of [ReOX3(PPh3)2] and [ReOX3(AsPh3)2] towards 2-(2-hydroxyphenyl)-1H-benzimidazole: Synthesis, X-ray studies, spectroscopic characterization and DFT calculations for [ReOX2(hpb)(EPh3)] and [ReO(OMe)(hpb)2]·MeCN

The paper presents a combined experimental and computational study of mono- and disubstituted Re(V) oxocomplexes obtained in the reactions of [ReOX₃(EPh₃)₂] (X = Cl, Br; E = P, As) with 2-(2-hydroxyphenyl)-1H-benzimidazole (Hhpb). From the reactions of [ReOX₃(PPh₃)₂] with Hhpb in molar ratio 1:1 cis and trans stereoisomers of [ReOX₂(hpb)(PPh₃)] were isolated, whereas the [ReOX₃(AsPh₃)₂] oxocompounds react with Hhpb to give only cis-halide isomers. The [ReOX₂(hpb)(EPh₃)] and [ReO(OMe)(hpb)₂]·MeCN complexes have been characterized spectroscopically and structurally (by single-crystal X-ray diffraction). The DFT and TDDFT calculations have been carried out for the trans-[ReOBr₂(hpb)(PPh₃)], cis-[ReOBr₂(hpb)(AsPh₃)] and [ReO(OMe)(hpb)₂], and their UV–Vis spectra have been discussed on this basis.     

Methylmercury and dimethylthallium complexes of 5-(4′-dimethylaminobenzylidene)-2-thiohydantoin (HDABTd): The crystal and molecular structures of HDABTd and [TlMe2(DABTd)(DMSO)]

The ligand 5-(4′-dimethylaminobenzylidene)-2-thiohydantoin (HDABTd) was prepared and its structure determined by X-ray diffraction. In the crystal, ligand molecules are linked in chains along the [110] direction by intermolecular N(3)–H(3)O(1)^I and N(1)–H(1)Sⁱⁱ hydrogen bonds. The complexes [HgMe(DABTd)] and [TlMe₂(DABTd)] were prepared by reaction of the ligand with methylmercury acetate or dimethylthallium hydroxide, and were characterized in the solid state by IR spectroscopy and in solution by conductivity measurements and ¹H, ¹³C, ¹⁹⁹Hg and ²⁰⁵Tl NMR spectroscopy. The dimethylthallium complex crystallized in DMSO solution as [TlMe₂(DABTd)(DMSO)], an X-ray diffraction study of which showed its thallium atoms to be coordinated to the two methyl C atoms, the oxygen atom of a DMSO molecule, the S and N(1) atoms of one DABTd ligand and, more weakly, to the oxygen atom of a neighbouring DABTd. This last interaction links the molecules of the complex in chains parallel to the b axis. Crystals of the methylmercury(II) complex contain three [HgMe(DABTd)]·DMSO structures per asymmetric unit, but poor data quality prevented complete refinement.     

Novel synthesis of 2-aminopentanedinitriles from 2-(bromomethyl)aziridines and their transformation into 2-imino-5-methoxypyrrolidines and 5-methoxypyrrolidin-2-ones

1-Arylmethyl-2-(bromomethyl)aziridines were transformed into 2-[N-(arylmethyl)amino]pentanedinitriles upon treatment with an excess of potassium cyanide in DMSO through an unprecedented and peculiar reaction mechanism, involving base-induced ring opening of intermediate 2-(cyanomethyl)aziridines into allylamines, followed by migration of the double bond out of the conjugation towards aldimines via enamine intermediates. The resulting aminopentanedinitriles served as substrates for the synthesis of novel 2-imino-5-methoxypyrrolidines upon treatment with sodium methoxide in methanol, which were either acetylated at the free imino group to afford the more stable N-acetylimino derivatives or hydrolyzed towards the corresponding synthetically relevant 5-methoxypyrrolidin-2-ones.     

A one-pot synthesis and mild cleavage of 2-[2- or 5-(alkylsulfanyl)pyrrol-1-yl]ethyl vinyl ethers by t-BuOK/DMSO: a novel and facile approach to N-vinylpyrroles

Substituted N-[2-(vinyloxy)ethyl]pyrroles, prepared in good yield through an allenic or acetylenic carbanion/isothiocyanate one-pot methodology from 2-(vinyloxy)ethyl isothiocyanate and allyloxyallene, methoxyallene, N,N-dimethyl-2-propyn-1-amine, and 3-methoxy-1-(methylsulfanyl)-1-propyne, are smoothly converted into the corresponding N-vinylpyrroles using t-BuOK/DMSO (room temperature). The reaction proceeds via elimination of vinyl alcohol from the N-[2-(vinyloxy)ethyl] substituent and represents a novel approach to N-vinylpyrroles.     

Conformational Features of Monochloro-substituted Tetrahydropyrans According to Data from <Emphasis Type="Italic">ab initio</Emphasis> Calculations and <Superscript>35</Superscript>Cl NQR

Nonempirical quantum-chemical calculations of 2-, 3-, and 4-chloro-substituted tetrahydropyrans by the RHF/6-31G(d) and MP2/6-31G(d) methods showed that their conformational energy increases in the transition from the 4- to the 3-chloro-substituted compound, while in the transition to the 2-substituted compound the sign changes. In each of these isomers the axial C-Cl and C-H bonds, situated in the geminal position in relation to the oxygen atom, are longer, while the electron density at their Cl and H atoms is higher than in the corresponding equatorial bonds.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 196–201, February, 2005.     

1-(2-Quinoxalyl)-, 1-[3,5-Di(trifluoromethyl)phenyl]-, 1-(2-Carboxyphenyl)-, and 1-Ethoxycarbonyl-4-oxo-4,5,6,7-tetrahydroindazoles

The corresponding 1-(2-quinoxalyl)-, 1-[3,5-di(trifluoromethyl)phenyl]-, and 1-ethoxycarbonyl-3-methyl-4-oxo-4,5,6,7-tetrahydroindazoles have been obtained from reactions of 2-acetyl-1,3-cyclohexanedione, its 5,5-dimethyl and 5-(2-furyl) derivatives, with 2-hydrazinoquinoxaline, 3,5-di(trifluoromethyl)phenylhydrazine, and ethoxycarbonylhydrazine. On interaction with ethoxycarbonylhydrazine the intermediate 2-[1-(-ethoxycarbonyl)hydrazino]ethylidene-1,3-cyclohexanediones were also isolated. From the potassium salt of 2-formyldimedone and 2-carboxyphenylhydrazine hydrochloride, 2-(2-carboxyphenyl)hydrazinomethylene-5,5-dimethyl-1,3-cyclohexanedione was obtained, the cyclization of which in ethanol in the presence of HCl led to 1-(2-carboxyphenyl)- and 1-(2-ethoxycarbonylphenyl)-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazole.     

Synthesis and structure of hydrazones obtained from hydrazides of [5-(4-pyridyl)-1,3,4-oxadiazol-2-ylthio]acetic or 2-[5-(4-pyridyl)-1,3,4-oxadiazol-2-ylthio]propionic acids

It has been shown by¹H NMR spectroscopy that hydrazones obtained by the condensation of hydrazides of [5-4-pyridyl)-1,3,4-oxadiazol-2-ylthio] acetic or 2-[5-(2-pyridyl)-1,3,4-oxadiazol-2-ylthio]propionic acids with aldehydes, ketones, and -dicarbonyl compounds exist in DMSO solution as a mixture of stereoisomeric forms.Institute of Chemistry, Vilnius LT-2600, Lithuania. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 966–971, July, 2000.     

Formation of 2‐(Phenylsulfonyl)resorcinols (=2‐(Phenylsulfonyl)benzene‐1,3‐diols) from Symmetrically Substituted Maleic Anhydrides (=Furan‐2,5‐diones)

Treatment of symmetrically substituted maleic anhydrides (=furan‐2,5‐diones) 6 with lithium (phenylsulfonyl)methanide, followed by methylation of the adduct with MeI/K₂CO₃ in acetone, give the corresponding 4,5‐disubstituted 2‐methyl‐2‐(phenylsulfonyl)cyclopent‐4‐ene‐1,3‐diones 8 (Scheme 3). Reaction of the latter with lithium (phenylsulfonyl)methanide in THF (?78°) and then with 4 mol‐equiv. BuLi (?5° to r.t.) leads to 5,6‐disubstituted 4‐methyl‐2‐(phenylsulfonyl)benzene‐1,3‐diols 9 (Scheme 4).     

3,3-二{2,2-二[4-(N,N-二取代氨基)苯基]乙烯基}-4,5,6,7-四氯-2-苯并[c]呋喃酮的合成

在对甲苯磷酸存在下,采用1,1-二[4-(N,N-二取代氨基)苯基]乙烯(3)和四氯苯酐在乙酸酐溶液中的缩合反应合成了3,3-二{2,2-二[4-(N,N-二取代氨基)苯基]乙烯基}-4,5,6,7-四氯-2-苯并[c]呋喃酮(4),产率89～93％。3由4,4＇-二(N,N-二取代氨基)二苯甲酮(1)与甲基碘化镁进行Grignard反应的产物经水解再脱水制得,产率85％～88.5％(以1为基准)。     

Synthesis of 1-(alkylamino)- and 1-(dialkylamino)benzimidazoline-2-thiones

Unlike 1-aminobenzimidazoles, 1-alkylaminobenzimidazoles are thiolated on fusing with sulfur without elimination of theN-amino group, yielding the previously unknown 1-(alkylamino)benzimidazoline-2-thiones. These compounds can be more conveniently obtained on a preparative scale by thiolation of 1-alkylacetamidobenzimidazoles with subsequent hydrolytic elimination of the acetyl group. When 1-(dialkylamino)benzimidazoles are fused with sulfur, they are converted into 1-(dialkylamino)benzimidazoline-2-thiones. By alkylation of 1-(methylamino)- and 1-(diethylamino)benzimidazoline-2-thiones with methyl iodide in alkaline media the corresponding 2-(methylthio)benzimidazoles were prepared.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2231–2235, November, 1995.The authors are grateful to the Contest Center of Basic Natural Science at St. Petersburg University for financial support of this study.     

Synthesis of 2,5-bis(2-aminothiazol-5-yl)-3,6-dichloro-1,4-benzoquinones

A series of 2-(2-aminothiazol-5-yl)-3,6-dichloro-5-diethylaminoethenyl-1,4-benzoquinones was synthesized from 2-(2-aminothiazol-5-yl)-3,5,6-trichloro-1,4-benzoquinones using acetaldehyde and diethylamine in toluene solution. Refluxing these compounds with substituted thioureas in acetonitrile in the presence of hydrochloric acid gives the corresponding 2,5-bis(2-aminothiazol-5-yl)-3,6-dichlorohydroquinones which can be oxidized to the target products with ferric chloride in aqueous DMF.Riga Technical University, Riga LV-1048, LatviaTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 835–839, June, 2000     

1-Ethylthio-2-[2-thienyltelluro]ethane (L) a new (Te, S) ligand: Synthesis and complexation with Ag(I), Cu(I), Pd(II) and Pt(II) – Single crystal structures of [PdCl2(L)] and bis(thienyl) tellurium(IV) chloride

Lithium 2-thienyltellurolate, generated from 2-thienyl lithium, reacts at −78 °C in THF with chloroethyl ethyl sulfide to give a (Te, S) ligand 1-ethylthio-2-[2-thienyltelluro]ethane (L) as a red oil. The complexes [PdCl₂(L)] (1), [PtCl₂(L)] (2), [Ag(L)₂][ClO₄] (3) and [CuBr(L)]₂ (4) were synthesized. The complex [HgCl₂(L)] on crystallization decomposed giving Th₂TeCl₂ (5) [where Th = 2-thienyl], which was characterized by X-ray diffraction on its single crystals. The ligand L and complexes 1–4 exhibit proton and carbon-13 NMR spectra, which are characteristic. The coordination through Te in 1–4 is indicated by downfield coordination shifts in the position of the TeCH₂ signal of L. Complex 1 was characterized by X-ray diffraction on its single crystals. The geometry around Pd is square planar. The Pd–Te, Pd–S and Pd–Cl bond lengths are 2.5040(4), 2.273(1) and 2.322(1)/2.380(1) Å, respectively. There are intermolecular interactions between Te (coordinated to Pd) and Cl, and sulfur and Cl. The Te–Cl and S–Cl distances, 3.401 and 3.488 Å, respectively, are shorter than the sum of the van der Waal’s radii (3.81 and 3.55 Å, respectively). The Pd–Pd distance between the two molecules is 3.4156(6) Å, greater than the sum of van der Waal’s radii (3.26 Å). The structure of 5 is typical of that of a tellurium(IV) compound (saw-horse type). The two Te–Cl bond lengths are identical, 2.480(1) Å. The geometry around Te in 5 can be best described as pseudo tetrahedral (trigonal bipyramidal with a lone pair on one corner of the triangle).     

Extraction-spectrophotometric determination of trace iron (II) in sea water with 2-[2-(3,5-dibromopyridyl)azo]-5-diethylaminobenzoic acid

An extraction-spectrophotometric method is described for the determination of traces of iron(II) with 2-[2-(3,5-dibromopyridyl)azo]-5-diethyl-aminobenzoic acid. The reagent forms a stable and blue 12 iron/reagent complex that can be extracted into chloroform. The apparent molar absorptivity of the iron(II) complex is 1.09 × 10⁵ 1 mol^–1 cm^–1 at 624 nm in chloroform. The reagent is relatively selective; interferences from cobalt, copper, nickel and vanadium can be removed by using dimethylglyoxime and EDTA. The method is applied to the determination of iron (II) in sea water and aluminium alloys with good precision and accuracy.     

Computational study of glycine–(water)3 complex by density functional method

Glycine–(water)₃ complexes have been studied by means of B3LYP density functional method using 6-311++G* basis set. In the complex considered here, the three water molecule are either attached to the carboxylic group or bridge between the amino group and carboxylic group of glycine. Four such complexes are studied. Relaxation energies, two-, three- and four-body interaction energies are obtained by applying many-body analysis to know their role in binding energy of the complex. The results are compared with recent work on glycine–(water)₃ complex with group as proton donor [A. Chaudhari, P.K. Sahu, S.L. Lee, J. Chem. Phys. 120 (2004) 170]. In the most stable structure of glycine–(water)₃ complex, the three water molecules are attached to the carboxylic group of glycine and it is 5.3 kcal/mol lower in energy than that of the most stable structure reported earlier. The three-body term from water–water–water interaction in the most stable in this work and that reported earlier is unique since the distances between the water molecules are almost same. The two-body term from water–water interaction has significant contribution to the total two-body term when the distance between water molecules is less than 3 Å.     

Synthese und Reaktionsverhalten von 3-(Bis(alkylthio)methylen)-3H-isobenzofuran-1-on-und 2-(Bis(alkylthio)methylen)-3(2H)-benzofuranon-Derivaten

Summary 3(Bis(alkylthio)methylene)-3H-isobenzofuran-1-ones2a–e and 2-(bis(alkylthio)methylene)-3(2H)-benzofuranone derivatives4a–c are obtained by reaction of phthalides1a–d or 3(2H)-benzofuranone (coumaranone3), respectively, with carbon disulfide under basic conditions followed by alkylation. The reaction behaviour of the new compounds2 and4 is investigated. 2-((2-Dimethylthio-1-oxo)ethyl)benzoic acid N,N-dimethylamide (7a) and 2-((2-dimethylthio-1-oxo)ethyl)-benzoic acid 2-methylpiperidide (7b) are surprisingly formed instead of the methylthio substitution products by treatment of2a with the corresponding amine in the presence of aluminum chloride.

Herrn Professor Dr. Dr. h. c.Waldemar Adam zum 60. Geburtstag gewidmet     

Determination of Lead Using a New Chromogenic Reagent 2-(2-Sulfo-4-acetylphenylazo)-7-(2,4,6-trichlorophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic Acid

A novel chromogenic reagent, 2-(2-sulfo-4-acetylphenylazo)-7-(2,4,6-trichlorophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid 1, was prepared by diazo coupling of 4-acetylaniline-2-sulfonic acid and 2,4,6-trichloroaniline to chromotropic acid through –N=N– groups. Based on this reagent, a simple, sensitive and selective spectrophotometric method was developed for the determination of lead. In 0.20M phosphoric acid medium, lead reacts with 1 to form a 1:2 blue complex with an absorption maximum of 654nm. Beers law is obeyed in the range of 0–0.6mgL^–1 of lead. The apparent molar absorptivity is 1.25×10⁵Lmol^–1cm^–1. The detection limit and quantification limit were found to be 0.63µgL^–1 and 2.1µgL^–1, respectively. The relative standard deviation for eleven replicate measurements was of 2.6%. The interference of foreign ions was also investigated. All the other foreign ions studied did not interfere with lead determination except for Ca(II) and Ba(II). The interference caused by Ca(II) and Ba(II) can be eliminated by prior extraction of lead with potassium iodide-methylisobutylketone (KI-MIBK). The proposed method was applied to the determination of lead in certified samples with satisfactory results.