Structure and photochromic and magnetic properties of 1-isopropyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-2<Emphasis Type="Italic">H</Emphasis>-pyrano[3,2-<Emphasis Type="Italic">b</Emphasis>]pyridinium] tris(oxalato)chromate(III)

Single crystals of 1-isopropyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-2H-pyrano[3,2-b]-pyridinium] tris(oxalato)chromate(III) (Sp)₃Cr(C₂O₄)₃ were prepared for the first time. The molecular and crystal structure of this salt was studied by X-ray diffraction. The crystal structure of the salt consists of the structural units [3(Sp)⁺…Cr(C₂O₄)₃ ³⁻], in which the charged pyranopyridinium moieties of the photochromic cations (Sp)+ are directed toward the oxalate groups, whereas the indoline moieties are directed into the cavities between the structural units. This structure appeared to be favorable for photochromic transformations in the crystals. Under UV irradiation of the (Sp)₃Cr(C₂O₄)₃ salt, the thermally stable closed form of spiropyran (λ_max = 370 nm) is transformed into the open form (λ_max = 574 and 603 nm). The reverse cyclization proceeds slowly in the dark (k = 1.0(2)·10⁻⁵ s⁻¹ and rapidly under visible light irradiation. The spectroscopic and photochromic properties of the oxalatochromate (Sp)₃Cr(C₂O₄)₃ are similar to those of the iodide SpI. The magnetic properties of (Sp)₃Cr(C₂O₄)₃ were studied before and after UV irradiation.     

Structures of transient species in the photochromic reaction of 1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indoline]: Time-resolved resonance Raman study of isotopically substituted analogues

Time-resolved resonance Raman spectra of seven kinds of isotopically substituted analogues of 1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indoline] in the photomerocyanine form have disclosed that only the vibrations of the cleaved benzopyran part are resonance enhanced significantly in cyclohexane and in acetonitrile solutions with 460-390 nm probe light. Dramatic changes in the resonance Raman spectra of the photomerocyanine on going from non-hydrogen-bond donor solvents to hydrogen-bond donor solvents can be interpreted as being due to changes in the relative contribution of ortho-quinoidal and zwitterionic forms in the resonance hybrid structure of the photomerocyanine: in cyclohexane and in acetonitrile the contribution of the ortho-quinoidal form is substantial, while in methanol the zwitterionic form is stabilized by hydrogen bonding with the solvent and the photomerocyanine takes an almost zwitterionic structure.     

Synthesis and electrochemical Reduction of 2,2′-diaryl-5,5,5′,5′-tetramethyl-3,3′-bi(pyrrol-3-ylidene)-4,4′(5<Emphasis Type="Italic">H</Emphasis>,5′<Emphasis Type="Italic">H</Emphasis>)-dione 1,1′-dioxides

2,2′-Diaryl-5,5,5′,5′-tetramethyl-3,3′-bi(pyrrol-3-ylidene)-4,4′(5H,5′H)-dione 1,1′-dioxides containing a carboxy, alkoxycarbonyl, or carbamoyl group in the para position of one or both benzene rings were synthesized. These compounds may be regarded as cyclic dinitrones with conjugated C=C bond. Mild aminolysis of carboxy groups in the title compounds may be used to introduce dinitrone fragments into oligonucleotide or polypeptide structures. Electrochemical reduction of the resulting amides involves reversible oneelectron transfer in the first step at a near-zero potential, which makes it possible to use the title compounds as electrochemically active labels in applied bioorganic electrochemistry.     

Synthesis of new substituted acetamide derivatives of 6′,7′-dimethoxy-2′,3′-dihydro-1′<Emphasis Type="Italic">H</Emphasis>-spiro[isoquinoline-1,4′-cyclopentane]-1′-carboxamide

Reaction of ethyl 6′,7′-dimethoxy-3′Н-spiro[isoquinoline-1,4′-cyclopentane]-1′-carboxylate with ammonia and isopropylamine afforded dihydroisoquinoline carboxamides that were reduced with NaBH₄ in amides of 6,7-dimethoxy-4-spirocyclopentane-1,2,3,4-tetrahydroisoquinoline-1-carboxylic acid. The reaction of unsubstituted carboxamide with chloroacetyl chloride led to chloroamide that reacted with versatile secondary amines and heterylthiols providing the corresponding substituted amino- and sulfanylamides of tetrahydroisoquinoline series.     

Synthesis and properties of 1-[(3-fluoroadamantan-1-yl)methyl]-3-R-ureas and 1,1′-(alkan-1,n-diyl)bis{3-[(3-fluoroadamantan-1-yl)methyl]ureas} as promising soluble epoxide hydrolase inhibitors

Russian Chemical Bulletin - A two-step procedure to synthesize (3-fluoroadamantan-1-yl)methyl isocyanate from (3-hydroxyadamantane)acetic acid that involves fluorination with Ishikawa’s...     

Structural and crystal chemistry analysis of (4<Emphasis Type="Italic">E</Emphasis>)- and (4<Emphasis Type="Italic">Z</Emphasis>)-6,6′,7,7′-tetrahydro-5H,5′H-4,4′-<Emphasis Type="Italic">bis</Emphasis>-1-benzothiophenes

(4E)-6,6′,7,7′-tetrahydro-5H,5′H-4,4′-bis-1-benzothiophene and (4Z)-6,6′,7,7′-tetrahydro-5H,5′H-4,4′-bis-1-benzothiophene are studied by means of X-ray diffraction. The intermolecular interaction energy is calculated and the structural subclass of each compound is derived. These compounds have been found to have similar full crystal energies and packing efficiencies. The observed pseudosymmetry effects are described.     

Solvent effects on the crystal photochromism of 4,4′-methylenebis{(<Emphasis Type="Italic">N</Emphasis>-3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butylsalicylidene)-2,6-dimethylaniline}

4,4′-methylenebis{N-(3,5-di-tert-butylsalicylidene)-2,6-dimethylaniline} formed a definite acetone-inclusion crystal by recrystallization with acetone. Through crystal-to-crystal solvent exchange of the crystal, various types of crystals were obtained. All resulting crystals exhibited photochromism. Rate constants of thermal fading of photochromes were found to depend on the number of solvent molecules included in the crystal unit. The thermal stability of photochrome is discussed in connection with molecular mobility in the crystal lattice.     

1-Benzyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-[2<Emphasis Type="Italic">H</Emphasis>]pyrano[3,2-<Emphasis Type="Italic">b</Emphasis>]-pyridinium] iodide,its hydrate,and a neutral precursor of the salts: synthesis,crystal structure,photochromic transformations in solutions and in crystals

A new 1-benzyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-[2H]pyrano[3,2-b]pyridinium] iodide, photochromic in the crystal state, was obtained. X-ray diffraction analysis was used for determination of crystal structures of the salt, its hydrate, and a neutral precursor. It was found that a replacement of the substituent in the indoline fragment leads to a considerable change in the crystal structure of both the neutral spiropyran and the salts as compared to the analogs studied earlier. Effects of crystal structure on photochromic properties were studied.     

Novel syntheses of some new 3,4-dihydrospiro{benzimidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridine-3,3′-indolin}-2′-one derivatives

Abstract  2-Methylbenzimidazole 1 reacted with 3-dicyanomethylidine-1-ethyl-2-oxoindoline 2 in ethyl acetate to afford 1-amino-2-cyano-3,4-dihydro-1′-ethylspiro{benzimidazo[1,2-a]pyridine-3,3′-indolin}-2′-one 6, which was used as a key intermediate in the synthesis of fused spiropolyheterocyclic derivatives of benzimidazopyridopyrimidine and/or benzimidazonaphthyridine nucleus incorporating an indoline moiety. Graphical abstract        

New cobalt and iron pivalate complexes with 2,2′:6′,2″-terpyridine: synthesis, structure, and magnetic properties

The mononuclear complexes (η³-terpy)M(Piv)²·MeCN (M = Fe ⁱⁱ (3) and Co ⁱⁱ (4), and Piv is the pivalate anion) were synthesized by the reactions of polymeric iron(ii) and cobalt(ii) pivalates with 2,2′:6′,2″-terpyridine (terpy). The oxidation of compound 3 affords the pentanuclear heterospin iron(ii,iii) complex (η³-terpy)Fe₅(μ₄-O)(μ₃-OH)(μ-OH)₂(μ-Piv)₇(η¹-Piv)₂ (5). All compounds were characterized by X-ray diffraction. Dedicated to the 90th anniversary of the L. Ya. Karpov Institute of Physical Chemistry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1186–1190, June, 2008.     

Synthesis and characteristics of <Emphasis Type="Italic">N</Emphasis>-(glyoxyldioxime)-<Emphasis Type="Italic">N</Emphasis>′-(2-hydroxybenzylidene)-1,4-diaminonaphthalene and its metal complexes

A new vic-dioxime, N-(glyoxyldioxime)-N′-(2-hydroxybenzylidene)-1,4-diaminonaphthalene, was synthesized proceeding from naphthalene. Its complexes of nickel, copper and cobalt were prepared. The vicdioxime and its complexes were charecterized by FT-IR, UV, ¹H NMR, mass spectrometry, elemental analysis, DTA/TG analysis techniques and conductometric measurements. Published in Russian in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 5, pp. 797–802. The text was submitted by authors in English.     

Benzoid–Quinoid tautomerism of schiff bases and their structural analogs: LVII. 2-[(3-oxo-5-phenylpyrazolidin-1-yl)methylidene]-1<Emphasis Type="Italic">H</Emphasis>-indene-1,3(2<Emphasis Type="Italic">H</Emphasis>)-dione

Potentially tautomeric azomethine imide, 2-[(3-oxo-5-phenylpyrazolidin-1-yl)methylidene]-1H-indene- 1,3(2H)-dione, has been synthesized by condensation of 5-phenylpyrazolidin-3-one with 2-(hydroxymethylidene)-1H-indene-1,3(2H)-dione. According to the IR, ¹H and ¹³C NMR, and electronic absorption spectroscopy data and DFT B3LYP/6-311++G(d,p) quantum chemical calculations, the title compound in solution exists as planar tricarbonyl tautomer stabilized by intramolecular hydrogen bond between the NH proton of the pyrazolidine fragment and carbonyl oxygen atom of the indene fragment. Its crystal structure was determined by X-ray analysis.     

An efficient synthesis of 1′,4′-dihydro-2′<Emphasis Type="Italic">H</Emphasis>-spiro[azetidin-2,3′-quinolin]-2′-one

A facile synthesis of 1′,4′-dihydro-2′H-spiro[azetidin-2,3′-quinolin]-2′-one is described. Synthetic highlights include simultaneous construction of azetidine ring by intramolecular alkylation and formation of spirocarbon center in excellent yield plus removal of p-methoxybenzyl (PMB) amide protective group in mild condition with good yield.     

Synthesis,structure, and complexing properties of 2,2′-{[(diisopropoxyphosphoryl)methyl]azanediyl}diacetic acid

Russian Journal of General Chemistry - 2,2′-{[(Diisopropoxyphosphoryl)methyl]azanediyl}diacetic acid has been synthesized by the Kabachnik–Fields reaction and its complexing ability...     

Synthesis,DFT calculations and characterisation of new mixed Pt(II) complexes with 3-thiolanespiro-5<Emphasis Type="Italic">′</Emphasis>-hydantoin and 4-thio-1<Emphasis Type="Italic">H</Emphasis>-tetrahydropyranspiro-5<Emphasis Type="Italic">′</Emphasis>-hydantoin

Cisplatin is an anticancer drug widely used in the treatment of a wide range of solid tumours (head and neck, lung, bladder etc.), testicular and ovarian cancers. Because of its severe toxicity profile and spontaneous development of drug resistance in tumours, a number of Pt(II) complexes have been synthesised and tested for anti-tumour activity. Some of the investigations have focused on using ligands bearing donor atoms other than N (e.g., S, P, O). Two new mixed Pt(II) complexes of the general formula cis-[Pt(NH₃)LCl₂] where L is 3-thiolanespiro-5′-hydantoin and 4-thio-1H-tetrahydropyranspiro-5′-hydantom were synthesised. The complexes were studied by elemental analysis, melting points, IR and ¹H NMR spectra. The hybrid DFT calculations were used for optimisation of the structure geometries of the ligands III, IV and their Pt(II) complexes V and VI. The structural parameters so calculated, such as bond lengths and angles, are in good agreement with the experimental data for similar hydantoins and their platinum complexes. The results showed that the geometries of complexes V and VI are plane square and the bounding of ligands III and IV with platinum ions is effected by the sulphur atom from the cyclic ring. The complexes thus obtained were chemically examined in comparison with previously synthesised and published complexes of the general formula cis-[PtL₂Cl₂] (VII and VIII) with the same ligands. The new compounds V and VI, as well as the previously investigated complexes (VII and VIII), were analysed for cytotoxicity in vitro on SKW-3 and HL-60 human tumour cell lines. The results showed that all the complexes exerted concentration-dependent anti-proliferative activity.     

Quantum-chemical study of spiro[indoline-2,2′-[2<Emphasis Type="Italic">H</Emphasis>]-chromenes] and their complexes with a silver cluster

Computer modeling (DFT B3LYP/6-31G(d,p)/SDD) of the structure and spectral characteristics of photochromic 1,3,3,8′-tetramethyl-6′-formylspiro[indoline-2,2′-[2H]-chromene] and 1,3,3-trimethyl-6′-methoxy-8′-formyl[spiroindoline-2,2′-[2H]-chromene] complexes adsorbed onto the surface of a 10-atom silver cluster has been performed. It has been demonstrated that, depending on the position of the formyl group in the quinoline ring and the isomeric form of the spirocyclic compound, the change in the band intensity in Raman spectra caused by complexation with the silver cluster can reach three orders of magnitude.     

Transformations of the extra ring in pheophorbide <Emphasis Type="Italic">a</Emphasis> methyl ester in the reaction with <Emphasis Type="Italic">N,N,N′,N′</Emphasis>-tetramethylmethanediamine

The reaction of N,N,N′,N′-tetramethylmethanediamine with pheophorbide a methyl ester gave the corresponding 13″-dimethylaminomethyl derivative and 13-N,N-dimethylamide derivative of chlorin e ₆ having a methyl acrylate moiety in the 15-position. Conditions were found for the synthesis of the latter both directly from pheophorbide a methyl ester and from its aminomethylation product. Probable mechanisms of the examined reactions were proposed.     

Zinc(II) complexes containing N′-aromatic group substituted N,N′,N-bis((1H-pyrazol-1-yl)methyl)amines: Synthesis,characterization, and polymerizations of methyl methacrylate and rac-lactide

A novel series of Zn(II) complexes [L_nZnCl₂] (L_n = L_A ? L_F) based on N,N′,N-bis((1H-pyrazol-1-yl)methyl)amine bidentate ligands, N,N-bis((1H-pyrazol-1-yl)methyl)-3,5-dimethylaniline [L_A], N,N-bis((1H-pyrazol-1-yl)methyl)-2,6-dimethylaniline [L_B], N,N-bis((1H-pyrazol-1-yl)methyl)-2,6-diethylaniline [L_C], N,N-bis((1H-pyrazol-1-yl)methyl)-2,6-diisopropylaniline [L_D], N,N-bis((1H-pyrazol-1-yl)methyl)-4-bromoaniline [L_E] and N,N-bis((1H-pyrazol-1-yl)methyl)benzhydrylamine [L_F], has been synthesized and characterized. X-ray structures of these Zn(II) complexes showed a distorted tetrahedral geometry. No interaction exists between the N_amine and the Zn(II) center in the [L_nZnCl₂] (L_n = L_A ? L_F) complexes, resulting in formation of an eight-membered chelate ring. [L_FZnCl₂] exhibited the highest catalytic activity (3.95 × 10⁴ g PMMA/mol·Zn·h) for the polymerization of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) at 60 °C and yielded high molecular weight (M_w) (11.0 × 10⁵ g/mol) of poly(methylmethacrylate) (PMMA). All the complexes resulted in syndiotactic enriched PMMA with high T_g (125–131 °C). The steric bulk of ligand architecture plays an influential role in controlling the catalytic activity and stereoregularity of the resultant PMMA. Further, alkyl derivatives [L_nZnMe₂] (L_n = L_A ? L_F) of synthesized Zn(II) complexes, generated in situ, showed moderate to high activities toward ring opening polymerization (ROP) of rac-lactide (rac-LA) and yielded heterotactic polylactide (PLA) with P_r up to 0.95 at ?50 °C. The activity and stereoselectivity toward ROP of rac-LA by these dimethyl Zn(II) complexes should be considered as a combined effect of steric hindrance and electronic density around the metal center.     

Synthesis and transformations of 4-amino-4′-(4-nitro-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-tri-azol-1-yl)- and 4-amino-4′-(1,2,3-triazolo[4,5-<Emphasis Type="Italic">c</Emphasis>]-1,2,5-oxadiazol-5-yl)- 3,3′-(NNO)-azoxy-1,2,5-oxadiazoles

Methods for the synthesis of 4-amino-4′-R-3,3′-(NNO)-azoxy-1,2,5-oxadiazoles (amino-azoxyfurazans) with 4-nitro-1,2,3-triazol-1-yl and 1,2,3-triazolo[4,5-c]furazan-5-yl substituents (R) by cycloaddition of morpholinonitroethylene to 4′-amino-4-azido-3,3′-(ONN)-azoxyfurazan or oxidative condensation of 3-R-4-aminofurazans with 4-trifluoroacetylamino-3-nitrosofurazan were elaborated. Related polycyclic azo derivatives were also synthesized. For preliminary communication, see Ref. 1. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 159–163, January, 2008.     

Synthesis,spectroscopic and crystallographic characterization of the cobalt(III) ternary mixed-ligand complexes of N(4)-allyl/methyl thiosemicarbazones, <Emphasis Type="Italic">N,N,N</Emphasis>′<Emphasis Type="Italic">,N</Emphasis>′-tetramethylethylenediamine and azide

Mixed-ligand ternary cobalt(III) complexes consisting of N,N,N′,N′-tetramethylethylenediamine (tmen), R-salicylaldehyde-N(4)-allyl/methyl thiosemicarbazones (R=3-OMe (L^I/L^II) or H (L^III/L^IV) and azide, of general formula [CoL(tmen)(N₃)], were synthesized and characterized by physico-chemical and spectroscopic methods. The crystal structure of [CoL^I(tmen)(N₃)] has a slightly distorted octahedral coordination geometry involving the O, N and S atoms of thiosemicarbazone.