Syntheses and structures of iron carbonyl complexes derived from N-(5-methyl-2-thienylmethylidene)-2-thiolethylamine and N-(6-methyl-2-pyridylmethylidene)-2-thiolethylamine

The reaction of N-(5-methyl-2-thienylmethylidene)-2-thiolethylamine (1) with Fe₂(CO)₉ in refluxing acetonitrile yielded di-(μ₃-thia)nonacarbonyltriiron (2), μ-[N-(5-methyl-2-thienylmethyl)-η¹:η¹(N);η¹:η¹(S)-2-thiolatoethylamido]hexacarbonyldiiron (3), and N-(5-methyl-2-thienylmethylidene)amine (4). If the reaction was carried out at 45 °C, di-μ-[N-(5-methyl-2-thienylmethylidene)-η¹(N);η¹(S)-2-thiolethylamino]-μ-carbonyl-tetracarbonyldiiron (5) and trace amount of 4 were obtained. Stirring 5 in refluxing acetonitrile led to the thermal decomposition of 5, and ligand 1 was recovered quantitatively. However, in the presence of excess amount of Fe₂(CO)₉ in refluxing acetonitrile, complex 5 was converted into 2-4. On the other hand, the reaction of N-(6-methyl-2-pyridylmethylidene)-2-thiolethylamine (6) with Fe₂(CO)₉ in refluxing acetonitrile produced 2, μ-[N-(6-methyl-2-pyridylmethyl)-η¹ (N_py);η¹:η¹(N); η¹:η¹(S)-2-thiolatoethylamido]pentacarbonyldiiron (7), and μ-[N-(6-methyl-2-pyridylmethylidene)-η²(C,N);η¹:η¹(S)-2- thiolethylamino]hexacarbonyldiiron (8). Reactions of both complex 7 and 8 with NOBF₄ gave μ-[(6-methyl-2-pyridylmethyl)-η¹(N_py);η¹:η¹(N);η¹:η¹(S)-2-thiolatoethylamido](acetonitrile)tricarbonylnitrosyldiiron (9). These reaction products were well characterized spectrally. The molecular structures of complexes 3, 7-9 have been determined by means of X-ray diffraction. Intramolecular 1,5-hydrogen shift from the thiol to the methine carbon was observed in complexes 3, 7, and 9.     

Synthesis and biotests of 2-aryl-5-arylmethylidene-substituted 1,3-oxazol-5(4<Emphasis Type="Italic">H</Emphasis>)-ones and <Emphasis Type="Italic">N</Emphasis>-methyl-3,5-dihydro-4<Emphasis Type="Italic">H</Emphasis>-imidazol-4-ones as combretastatin A-4 analogs

A series of 2-aryl-5-arylmethylidene-1,3-oxazol-5(4H)-ones and 2-aryl-5-arylmethylidene-N-methyl-3,5-dihydro-4H-imidazol-4-ones was synthesized as structural analogs of combret- astatin A-4 (a compound possessing antitumor activity). (5Z)-5-[(4-Methoxyphenyl)methyl-idene]-3-methyl-2-(4-methylphenyl)-3,5-dihydro-4H-imidazol-4-one was found to exhibit the highest cytotoxicity against cells of human A549 lung carcinoma line (EC₅₀ = 6±0.8 μmol L^?1).     

Highly regioselective direct halogenation: a simple and efficient method for preparing 4-halomethyl-5-methyl-2-aryl-1,3-thiazoles

An unprecedented C4-methyl regioselective halogenation of 4,5-dimethyl-2-aryl-1,3-thiazoles (1) has been accomplished. The reaction of compound 1 with N-chlorosuccinimide and N-bromosuccinimide under mild conditions provides an efficient and operationally simple method for obtaining 4-chloromethyl-5-methyl-2-aryl-1,3-thiazoles (2) and 4-bromomethyl-5-methyl-2-aryl-1,3-thiazoles (3), respectively, in good yields without the formation of 4-methyl-5-halomethyl regioisomers.     

Synthesis of 1,2,4- and 1,3,4-oxadiazoles from 1-aryl-5-methyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazole-4-carbonyl chlorides

5-Substituted 2-(1-aryl-5-methyl-1H-1,2,3-triazol-4-yl)-1,3,4-oxadiazoles were synthesized by reaction of 1-aryl-5-methyl-1H-1,2,3-triazole-4-carbonyl chlorides with the corresponding 5-substituted 1H-tetrazoles. 5-Methyl-1-phenyl-1H-1,2,3-triazole-4-carbonyl chloride reacted with N′-hydroxybenzimidamides to give 3-aryl-5-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-1,2,4-oxadiazoles. Reactions of 4-(5-methyl-1H-1,2,3-triazol-1-yl)benzoic acid with N′-hydroxybenzimidamides resulted in the formation of 3-aryl-5-[4-(5-methyl-1H-1,2,3-triazol-1-yl)phenyl]-1,2,4-oxadiazoles.     

Synthesis of 4-(2-hydroxy-1-methyl-5-oxo-1H-imidazol-4(5H)-ylidene)-5-oxo-1-aryl-4,5-dihydro-1H-pyrrole-3-carboxylates, a new triazafulvalene system

(2E,3Z)-2-(1-Methyl-2,5-dioxoimidazolidin-4-ylidene)-3-[(arylamino- or heteroarylamino)methylene]succinate 5 obtained by [2+2] cycloaddition of (5Z)-5-[(dimethylamino)methylene]-3-methylimidazolidine-2,4-dione (1) and dimethyl acetylenedicarboxylate (2) followed by substitution of the dimethylamino group with aromatic or heteroaromatic amines, afforded by heating in ethanol in the presence of potassium hydroxide, potassium salts 6. Acidification of 6 with hydrochloric acid afforded mixtures of (E)- and (Z)-isomers of methyl 4-(2-hydroxy-1-methyl-5-oxo-1H-imidazol-4(5H)-ylidene)-5-oxo-1-phenyl-4,5-dihydro-1H-pyrrole-3-carboxylates. On the other hand, alkylation of compounds 6 with methyl iodide or benzyl bromide produced the corresponding methyl (E)-4-(2-methoxy- or 2-benzyloxy-1-methyl-5-oxo-1H-imidazol-4(5H)-ylidene)-5-oxo-1-phenyl-4,5-dihydro-1H-pyrrole-3-carboxylates 9, derivatives of a new triazafulvalene system.     

Synthesis, structure, electrochemical properties, cytotoxic effects and antioxidant activity of 5-amino-8-methyl-4H-benzopyran-4-one and its copper(II) complexes

The chromone derivative 5-amino-8-methyl-4H-benzopyran-4-one (ligand) (1) has been used to obtain a series of Cu(II) complexes 2-4 as potential anticancer compounds. The molecular structures of ligand 1 and its Cu(II) complex 3 have been determined by X-ray crystallography. The cytotoxicity of all obtained compounds has been evaluated on melanoma A375 cell line. The ability of compounds 1-4 to take part in redox reactions and their antioxidant activity have been studied.     

Noncyclic dimer of 4-methyl-2-dimethylaminooxazole

Conclusions The reaction of N, N-dimethylurea with bromoacetone in the presence of glacial AcOH leads to a mixture of 4-methyl-2-dimethylaminooxazole and its dimer, and specifically 4-methyl-4-(4-methyl-2-dimethylamino-5-oxazolyl)-2-dimethylamino-^2,3-oxazoline.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1680–1682, July, 1977.     

Substituted pyridines 5-methyl-4-benzyl-2-styryl(phenylethynyl)pyridines

5-Methyl-4-benzyl-2-styrylpyridine (II), its p-dimethylaminostyryl analog IV, and 5-methyl-4-benzyl-2-(1,3-dioxo-2-hydrindenyl)pyridine (V) have been prepared. II has been converted into 5-methyl-4-benzyl-2-phenylethynylpyridine (VII), 5-methyl-4-benzylpyridine-2-carboxylic acid (VIII), and 3-styryl-6, 7-benzoisoquinoline (X).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1228–1231, September, 1970.     

Research in the imidazole series. 96. Reaction of 1-methyl-4-nitro-5-chlorimidazole with phenols, naphthols, and 8-hydroxyquinoline

By reactions of 1-methyl-4-nitro-5-chlorimidazole with 4-nitrophenol, - and -naphthols, and 8-hydroxyquinoline, a number of 1-methyl-4-nitro-5-aryl(heteryl)oxyimidazoles have been obtained. With aminophenols, under analogous conditions, 1-methyl-4-nitro-5-hydroxyphenylaminoimidazoles have been obtained.For Communication 95, see [1].Novokuznetsk Scientific-Research Chemical-Pharmaceutical Institute, Novokuznetsk 654034, Russia. Center for Medicinal Chemistry, All-Russian Scientific-Research Chemical-Pharmaceutical Institute, Moscow 119815. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 327–329, March, 1998.     

Binuclear copper(II) complexes with acyldihydrazones of 4-formyl-5-hydroxy-3-methyl-1-phenylpyrazoles

The synthesis of copper(II) binuclear complexes with acyldihydrazones of saturated carboxylic acids and 4-formyl-5-hydroxy-3-methyl-1-phenylpyrazoles in which the coordination polyhedra are connected by polymethylene chains of different length (two to five units) is described. The complexes were studied by chemical and thermal analysis, IR spectroscopy, and EPR. The molecular and crystal structure of the copper(II) complex with glutaric acid and 1-(4′-chlorophenyl)-4-formyl-5-hydroxy-3-methylpyrazole acyldihydrazone (H₄L) described as [Cu₂L·2Py] · Py · 4H₂O was determined by X-ray diffraction. The crystals are orthorhombic: a = 24.789(7) Å, b = 39.319(9) Å, c = 4.6336(14) Å, space group Pnma, Z = 4. The number of symmetrically unrelated reflections is 4716, R = 0.0606, R _w = 0.1307. The central atoms are separated by a chain of eight σ bonds and are located at a distance of 8.939 Å. The copper coordination polyhedron is a square. A specific feature of the crystal structure is the stacking interaction involving chelate rings and the pyrazole ring, resulting in stacks of molecular complexes. The EPR spectrum of a solution of the complex based on the acyldihydrazone of succinic acid and 4-formyl-5-hydroxy-3-methyl-1-phenylpyrazole recorded at room temperature exhibits seven HFS lines with an intensity ratio of 1: 2: 3: 4: 3: 2: 1 and a constant of 33.3 G as a result of exchange coupling of the unpaired electrons to the two equivalent copper nuclei. An increase in the length of the polymethylene chain to 3–5 units or introduction of the para-chlorine atom into the benzene ring hampers the exchange interactions, and the EPR spectrum shows a signal of four HFS lines with a constant of 55–70 G typical of monomeric copper(II) complexes.     

Synergistic extraction of uranium(VI) with 1-phenyl-3-methyl-4-acylpyrazolone-5 and neutral extractants

The synergistic extraction of uranium(VI) from hydrochloric acid solution with five chelating agents: 1-phenyl-3-methyl-4-benzoylpyrazolone-5 (PMBP), 1-phenyl-3-methyl-4-acetylpyrazolone-5 (PMAP), 1-phenyl-3-methyl-4-(2-chlorobenzoyl)pyrazolone-5 (PMCBP), 1-phenyl-3-methyl-4-(p-nitrobenzoyl)pyrazolone-5 (PMNBP) and 1-phenyl-3-methyl-4-trifluoroacetylpyrazolone-5 (PMTFP) plus the neutral extractants tributylphosphate (TBP), dioctyl sulfoxide (DOSO) and trioctylphosphine oxide (TOPO) in chloroform has been investigated. The extraction coefficients have been found to be greater for such mixtures than the individual component. The formulas of the extracted species have been determined to be UO₂A₂B (where HA = chelating agent, B = neutral extractant). Extraction power of these chelating agents increases as follows: PMCBP>PMNBP>PMTFP=PMBP>PMAP. Synergistic extraction power of the neutral extractants increases as follows: TOPO>DOSO>TBP. The extraction equilibrium constants have been calculated. The mechanism of the synergistic extraction and possible structure of the extracted species are discussed.     

Synthesis of new pyrimido[4,5-d]pyrimidine derivatives from 5-acetyl-6-methyl-4-methylsulfanylpyrimidine-2(1H)-thiones and guanidine

Reactions of 5-acetyl-1-aryl(alkyl)-6-methyl-4-methylsulfanylpyrimidine-2(1H)-thiones (prepared from diacetylketene N,S-acetal) with guanidine afforded 3-alkyl- and 3-aryl-7-amino-5-methyl-4-methylidene-3,4-dihydropyrimido[4,5-d]pyrimidine-2(1H)-thiones. By-products of these reactions (5-acetyl-1-alkyl(aryl)-6-methyl-2-thiouracils) can also be obtained from the starting pyrimidinethiones and EtONa in EtOH. Pyrimidopyrimidinethiones can react with MeOH at the methylidene group in the presence of MeONa.     

Azaindole derivatives. 66. 1,6-disubstituted 4-methyl-5-cyano-7-azaindolines

A general method was developed for the synthesis of 1,6-disubstituted 4-methyl-5-cyano-7-azalndolines from the readily available ammonium salt of 2,6-dihydroxy-3-(-hydroxyethyl)-4-methyl-5-cyanopyridine through the corresponding N-substituted ammonium salts and N-substituted 2-amino-3-(-hydroxyethyl)-4-methyl-5-cyano-6-hydroxypyridines with treatment of the latter by POCl₃. This method gives a 40% yield of 4-methyl-5-cyano-7-azaindoline compounds containing various aralkyl or alkyl substituents at N-1 and a hydroxy group or halogen atom at C-6 in three steps.For Communication 65, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 84–88, January, 1985.     

Enantioselective diethylzinc addition to the exocyclic CN double bond of some 4-arylideneamino-3-mercapto-6-methyl-4H-1,2,4-triazin-5-one derivatives

4-Arylideneamino-3-mercapto-6-methyl-4H-1,2,4-triazin-5-ones 2a–f have been evaluated as substrates in the enantioselective diethylzinc addition reaction in the presence of (1S,2R)-N-alkyl-N-benzylnorephedrines 3a–d as chiral ligands. The utility of using a dual catalytic system (amino alcohol/halosilane) for the diethylzinc addition reaction has been also examined. The addition products 4-(1-arylpropyl)amino-3-mercapto-6-methyl-4H-1,2,4-triazin-5-ones 4a–f were obtained in high yields and with enantiomeric excesses of up to 92%. The treatment of arylimines 2a–f with a diethylzinc reagent did not affect the hetero-ring opening although the CN double bond of the lateral chain did undergo an addition reaction to yield the C-ethylated products 4a–f. The reductive cleavage of the 1,2,4-triazinyl heterocyclic ring from addition products 4a–f led smoothly to the corresponding free primary amines 5a–f without a significant loss of enantiomeric purity.     

Synthesis and Structure of 4-Indolyl-5-(thieno[3,2-<Emphasis Type="Italic">b</Emphasis>]pyrrol-6-yl)imidazoles

A procedure was proposed for regioselective acylation of methyl 2-methyl-4H-thieno[3,2-b]-pyrrole-5-carboxylate with 2-(3-indolyl)-2-oxoacetyl chloride. Reactions of the resulting methyl 6-[2-(3-indolyl)-1,2-dioxoethyl]-2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate with aromatic aldehydes and ammonium acetate in acetic acid afforded the corresponding methyl 6-[2-aryl-4-(3-indolyl)imidazol-5-yl]-2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylates. The structure of methyl 6-[2-(4-chlorophenyl)-4-(3-indolyl)imidazol-5-yl]-2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate was studied by X-ray analysis.     

Absorption spectra of 2-alkylnitramino-substituted 4(or 6)-methyl-5-nitropyridines and 2-(N-alkyl-N-nitrosoamino)-substituted 4(or 6)-methyl-3(or 5)-nitropyridines

Electronic spectra of nine title compounds were measured and the substituent effect on _max and _max has been discussed. Competitive electron withdrawing by both the nitro groups in a molecule and a disturbance of mutual electronic interaction of substituent by a stericortho effect were found. The preparation of five new 2-(N-alkyl-N-nitrosoamino)-4-and6-methyl-5-nitro-and2-(N-methyl-N-nitrosoamino)-6-methyl-3-nitropyridines is described.Department of Organic Chemistry, Academy of Economics, PL-53-342 Wroclaw, Poland. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 632–636, May, 1997.     

New metal chelates of 5-amino-4-azopyrazoles: The crystal and molecular structure of bis{1-phenyl-3-methyl-4-(<Emphasis Type="Italic">p</Emphasis>-tolyl)azo-5-(<Emphasis Type="Italic">p</Emphasis>-carboxymethoxyphenyl)pyrazolamidato}copper(II)

The reactions of 1,3-alkyl(aryl) derivatives of 5-amino-4-azopyrazoles (HL) with copper(2+) acetate afford metal chelates CuL₂. Complexes with the CuN₄ chromophore containing a substituted amino group (X = NR) as a donor, like their azomethine analogues, have a pseudotetrahedral structure. Copper chelates with X = NH are planar. The X-ray diffraction data and an additional hyperfine structure (ahfs) from ¹⁵N atoms of the azo group in the labeled complexes provide evidence for the formation of six-membered metallocycles. The coordination polyhedron in bis{1-phenyl-3-methyl-4-(p-tolyl)azo-5-(p-carboxymethoxyphenyl)pyrazolamidato}Cu(II) can be described as a pseudotetrahedron.     

Coordination compounds of dysprosium(III) with 3-methyl-1-phenyl-4-formylpyrazol-5-one diacyldihydrazones

Coordination compounds of dysprosium(III) with diacyldihydrazones of saturated dicarboxylic acids, imino-, oxo-, and thiodiacetic acids, and 3-methyl-1-phenyl-4-formylpyrazol-5-one (H₄L) are described. [Dy₂(H₂L^O)₃] · 7.5CH₃OH · 3H₂O was subjected to X-ray diffraction analysis: space group \(R\bar 3\) , a = 17.349(1) Å, c = 65.669(4) Å, Z = 6, R = 0.076, R _w = 0.243 (5301 reflections with I ≥ 2σ(I)). The complex is established to have a binuclear structure and contain dysprosium ions linked via three bridging ligands. The coordination polyhedron of the Dy atom had a three-capped trigonal prism geometry. The magnetic properties of the synthesized complexes were studied.     

Reaction of 3-oxo-3-R<Superscript>1</Superscript>-<Emphasis Type="Italic">N</Emphasis>-R<Superscript>2</Superscript>-propanethioamides with 2-amino-5-R-pyridines

Direction of a reaction between 3-oxo-3-R¹-N-R²-propanethioamides and 2-amino-5-R-pyridines in acetic acid depends on the structure of initial thioamides: at R¹ = Me, R² = Ar, Et 2-methyl-7-R-4H-pyrido[1,2-a]-pyrimidine-4-thiones are obtained, and at R¹ = Ar, R² = Me form 1-methyl-5-(N-methylaminothiocarbonyl)-4,6-diaryl-1,2-dihydropyridine-2-thiones.