1,6- and 1,7-regioisomers of dinitro- and diamino-substituted perylene bisimides: synthesis,photophysical and electrochemical properties

1,6- and 1,7-regioisomers of dinitro- (1,6-3 and 1,7-3) and diamino-substituted perylene bisimides (1,6-1 and 1,7-1) were synthesized. The regioisomers 1,6-3 and 1,7-3 were successfully separated by high performance liquid chromatography and characterized by 500 MHz ¹H NMR spectroscopy. Subsequently, the reduction of 1,6-3 and 1,7-3 afforded the corresponding diaminoperylene bisimides 1,6-1 and 1,7-1, respectively. This is the first time 1,6-regioisomers of dinitro- and diamino-substituted perylene bisimides are obtained in pure form. The photophysical and electrochemical properties of 1,6-3 and 1,7-3 were found to be almost the same. However, the regioisomers 1,6-1 and 1,7-1 exhibit significant differences in their optical characteristics. The absorption spectrum of 1,6-1 covers a larger part of the visible region compared to that of 1,7-1. Upon excitation, 1,6-1 also show larger dipole moment change than that of 1,7-1. Time-dependent density functional theory calculations are reported on these dyes in order to rationalize their electronic structure and absorption spectra.     

Recent advances in "formal" ruthenium-catalyzed [2+2+2] cycloaddition reactions of diynes to alkenes

"Formal" and standard RuII-catalyzed [2+2+2] cycloaddition of 1,6-diynes to alkenes gave bicyclic 1,3-cyclohexadienes in relatively good yields. When terminal 1,6-diynes 1 were used, two isomeric bicyclic 1,3-cyclohexadienes 4 or 6 were obtained, depending on the acyclic or cyclic nature of the alkene partner. When unsymmetrical substituted 1,6-diynes 7 were used, the reaction with acyclic alkenes took place regio- and stereoselectively to afford bicyclic 1,3-cyclohexadienes 8. A cascade process that behaves as a "formal" RuII-catalyzed [2+2+2] cycloaddition explained these results. Initially, a Ru-catalyzed linear coupling of 1,6-diynes 1 and 7 with acyclic alkenes occurs to give open 1,3,5-trienes of type 3, which after a thermal disrotatory 6e(-) pi-electrocyclization led to the final 1,3-cyclohexadienes 4 and 8. When disubstituted 1,6-diyne 10 was used with electron-deficient alkenes, new exo-methylene cyclohexadienes 12 arose from a competitive reaction pathway.     

Analytical Determination of 1,6-Anhydro-β-D-Glucopyranose and Kinetic Studies Under Hydrothermal Conditions

1,6-Anhydro-β-D-giucopyranose was identified for the first time in aqueous solutions obtained by hydrothermolysis of cellulosic matter. The identification and quantitative determination of the 1,6-anhydro-β-D-glucopyranose, as well as of further degradation and conversion products, was accomplished by means of HPLC. For kinetic studies, 1,6-anhydro-β-D-glucopyranose was degraded in aqueous solution under hydrothermal conditions in the range of 200-240°C. A kinetic model covering both formation and decomposition of 1,6-anhydro-β-D-glucopyranose is proposed.     

Trans Benzoyl Migration in 1.6-Anhydro-2-azido-4-O-benzoyl-2-deoxy-β-D-glucopyranose in Non-Aqueous Basic Medium

When 1,6-anhydro-2-azido-4-O-benzoyl-2-deoxy-β-D-glucopyranose (¹ (l) was treated with allyl bromide in benzene-tetrahydrofuran solution in the presence of sodium hydride, we obtained the expected reaction product, 3-O-allyl-1,6-anhydro-2-azido-4-O-benzoyl-2-deoxy-β-D-glucopyranose (2), and the rearranged compounds 1,6-anhydro-2-azido-3-O-benzoyl-2-deoxy-β-D-glucopyranose (3) and 4-O-allyl-1,6-anhydro-2-azido-3-O-benzoyl-2-deoxy-β-D-glucopyranose (4).     

Synthesis of novel push-pull-type solvatochromic 2′-deoxyguanosine derivatives with longer wavelength emission

We synthesized novel push-pull-type fluorescent guanosine derivatives, ^CNG and ^AcG containing 1,6- and 2,7-disubstituted pyrene chromophores. 1,6-Disubstituted pyrene derivatives, 1,6-^CNG (3b) and 1,6-^AcG (3c), exhibited highly solvatochromic fluorescence emission at longer wavelength (∼540 nm). The environmentally sensitive fluorescent deoxyguanosines such as 3b and 3c can be used as powerful tools for structural studies of nucleic acids and molecular diagnostics.     

Electrolytic ethoxylation of several γ-furylalkanols

Compounds of the 2-ethoxy-1,6-dioxaspiro[4.4]-3-nonene series were obtained during the electrolysis of solutions of primary, secondary, and tertiary-furylalkanols in ethanol as a result of intramolecular alkoxylation. Depending on the conditions, catalytic hydrogenation of the products leads to the formation of 2-ethoxy-1,6-dioxaspiro[4.4]nonanes or 1,6-dioxaspiro [4.4 ]nonanes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1303–1305, October, 1970.     

Synthesis of Some Substituted Naphthalenes as Potential Intermediates for Polyethers and Terpenoids

1-Benzyloxy-5-hydroxynaphthalene and 1,6-dimethyl-5-hydroxynaphthalene were prepared from 5-methoxy--tetralone. 6-Methoxy--tetralone was converted to 1,6-dimethoxy-2-isopropylnaphthalene.     

Reaction of 3,4-dioxohexane-1,6-dioic acid esters with 2,4-dinitrophenylhydrazine

Reaction was studied of 3,4-dihydroxyhexa-2,4-diene-1,6-dioic acid esters with 2,4-dinitrophenylhydrazine that led to the formation of esters of (3E)-3-[2-(2,4-dinitrophenyl)-hydrazinylidene]-4-oxohexane-1,6-dioic and (3E,4E)-3,4-bis[2-(2,4-dinitrophenyl)hydrazinylidene]-hexane-1,6-dioic acids. The structural features of compounds synthesized were established from the data of IR and NMR spectra and X-ray diffraction (XRD) analysis.     

Study of furan compounds

The electrolytic alkoxylation of several furan aldehydes and ketones was accomplished. It is shown that the electrolytic methoxylation of the aldehydes is an intramolecular reaction and leads to compounds of the 2,7-dimethoxy-1,6-dioxaspiro[4.4]-3-nonene series. Depending on the conditions, 2,7-dimethoxy-1,6-dioxaspiro[4.4]nonanes and 1,6-dioxaspiro [4.4]-nonanes were synthesized by the catalytic hydrogenation of the latter. The corresponding -carbonyl-containing 2,5-dimethoxy-2,5-dihydrofurans are formed in the case of the methoxylation of the furan ketones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1155–1158, September, 1971.     

Novel approach toward the preparation of 1,6-enynes — substrates for the intramolecular Pauson-Khand cyclization

A novel approach to the synthesis of polysubstituted 1,6-enynes is elaborated based on the protocol of the three-component coupling of arenesulfenyl chlorides, dicobalthexacarbonyl complexes of conjugated enynes, and nucleophiles of the -donor type and a possibility to employ the 1,6-enyne derivatives thus prepared as the substrates for the intramolecular Pauson—Khand cyclization is demonstrated.     

Functionalization of benzo[b][1,6]naphthyridine derivatives

Two routes to consecutive functionalization of 3-chloro-4-cyanobenzo[b][1,6]naphthyridine (1a) at positions 3 and 10 were developed. Oxidation of compound 1a with m-chloroperbenzoic acid in acetone leads to 3-chloro-4-cyano-10-oxobenzo[b][1,6]naphthyridine, while in acetic acid, the reaction gives 3-chloro-4-cyano-10-(3-chlorobenzoyloxy)-5-hydroxy-5,10-dihydrobenzo[b][1,6]naphthyridine. The reactions of 1a with some C-nucleophiles give -adducts at position 10. The reactions of N,N-dimethylamide acetals with chloride 1a leads to 4-cyano-3-dimethylaminobenzo[b][1,6]naphthyridine.     

Stereoselective Cyclopolymerization of Polar 1,6‐Heptadiynes by Novel,Tailor‐Made Ruthenium‐Based Metathesis Catalysts

Summary: The cyclopolymerization of 4,4‐bis(hydroxymethyl)‐1,6‐heptadiyne ( M1 ), 4‐(carboxyethyl)‐1,6‐heptadiyne ( M2 ), 4‐(hydroxymethyl)‐1,6‐heptadiyne ( M3 ), and 4‐carboxy‐1,6‐heptadiyne ( M4 ) using five different well‐defined metathesis initiators was investigated. Control of molar mass was achieved with catalysts bearing trifluoroacetate ligands. ¹³C NMR experiments showed that poly‐ M2 , prepared by the action of any catalyst consisted solely of five‐membered ring structures, i.e., 1,2‐(cyclopent‐1‐enylene)vinylene units. Effective conjugation lengths of all polymers were calculated from the corresponding UV‐Vis absorption maxima, which varied reversibly with temperature.

     

1,3,4,6-Tetracarbonyl Compounds: V. Reaction of 1,6-Disubstituted 3,4-Dihydroxy-2,4-hexadiene-1,6-diones with 2,3-Diaminopyridine

1,6-Disubstituted 3,4-dihydroxy-2,4-hexadiene-1,6-diones having two contiguous -dicarbonyl fragments readily react with 2,3-diaminopyridine to give (2Z,3Z)-bis(acylmethylene)-1,2,3,4-tetrahydropyrido[2,3-b]pyrazines.     

Reaction of tetracyclone with the ethyl ester of phenylphosphonous acid

Conclusions Ethyl phenylphosphonite in the presence of triethylamine is added at the carbonyl group of tetracyclone with the formation of -hydroxyphosphinate, which upon heating is converted to products which are identical to the products of 1,6- and 1,4-addition to a conjugated system of tetracyclone; in the presence of a base only the 1,6-addition occurs.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No, 6, pp. 1345–1348, June, 1979.     

Ruthenium(ii)-catalyzed regioselective 1,6-conjugate addition of umpolung aldehydes as carbanion equivalents

One of the most efficient and reliable approaches to construct C–C bonds involves the conjugate addition of carbon nucleophiles to electron-deficient ketones. Yet, 1,6-conjugate additions of extended conjugated systems largely remain underexplored due to difficulties in controlling the regioselectivity. Herein, we report umpolung aldehydes as carbanion equivalents for highly regioselective 1,6-conjugate addition reactions to unsaturated ketones, with preliminary studies of the enantioselective variant. The synergy of ruthenium(ii) catalyst and electron-rich, bidentate phosphine ligand is essential for the reactivity and selectivity under mild reaction conditions.

Highly regioselective 1,6-conjugate addition was developed using hydrazone as carbanion equivalent catalyzed by ruthenium under mild conditions.     

A novel strategy to assemble achiral ligands to chiral helical polyrotaxane structures

Using the achiral N,N'-bis(2-pyridylmethyl)-1,6-hexanediamine ligand bearing two end pyridyl groups as the source of conformational chirality, a novel type of TMeQ[6]-based helical polyrotaxane was prepared and characterized by X-ray crystallography and (1)H NMR spectroscopy. The chirality of the polyrotaxane was generated from twisting of the hexylidene of the N,N'-bis(2-pyridylmethyl)-1,6-hexanediamine "string" when bound within the hydrophobic cavity of TMeQ[6]. Two opposite chiral helical polyrotaxanes crystallize as a racemic compound.     

N-Alkylation of Unsymmetrical 1,6-Dihydro-1,2,4,5-tetrazine Under Alkali Condition

6-Methyl-3-phenyl-1,6-dihydro-1,2,4,5-tetrazine was stable in alkali solution at room temperature and decomposed gradually to form 1,2-dibenzylidenehydrazine. The plausible mechanism of the reaction is discussed. Because it was stable for a period of time, a convenient and effective method for synthesis of 1-alkyl-1,6-dihydro-1,2,4,5-tetrazines has been developed. The starting 1,6-dihydro-1,2,4,5-tetrazine can be alkylated with alkyl halides in methanol and lithium hydroxide monohydrate as a base at room temperature.     

Improved synthesis of 6-amino-6-deoxy-d-galactono-1,6-lactam and d-mannono-1,6-lactam from corresponding unprotected d-hexono-1,4-lactones

Regioselective bromination of unprotected d-galactono-1,4-lactone and d-mannono-1,4-lactone with PPh₃/CBr₄ led to 6-bromo-6-deoxy derivatives. These intermediates were treated with LiN₃ and hydrogenated to give 6-amino-6-deoxy-d-galactono-1,6-lactam (8) and 6-amino-6-deoxy-d-mannono-1,6-lactam (13) in 74 and 67% overall yield, respectively.     

Theoretical and experimental study of the transformation of 2-pyridone-5-amide into nitrile

Molecular and crystal structures of 2,4-dimethyl-6-oxo-1,6-dihydropyridine-3-carboxamide (1), 2,4-dimethyl-6-oxo-1,6-dihydropyridine-3-carbonitrile (2), and 2-chloro-4,6-dimethylniсotinonitrile (3), which are the products of sequential transformations, are studied by means of single crystal diffraction. The procedure for synthesizing each compound is described. All of the compounds are characterized using IR and ¹H NMR spectra. Possible reaction pathways are simulated using the density functional theory (DFT).     

The synthesis, spectroscopic, electrochemical and X-ray diffraction characterization of novel bridged ferrocene precursors for use in self-assembled monolayers

The synthesis of 1,6-diferrocenylhexane-1,6-dione (I), 1-ferrocenylcarbonyl-2-ferrocenylcyclopentene (II) and 1,6-diferrocenylhexane (III) is reported. All three compounds were characterized by ¹H NMR, ¹³C NMR, and infra-red spectroscopy, mass spectrometry, cyclic voltammetry and chronoamperometry. Compounds I and III each exhibit a single two electron transfer, while compound (II) exhibits two single electron transfers. Compounds (I) and (II) were further studied by single crystal X-ray diffraction. In compound (I), both carbonyl groups are in plane with the adjacent ferrocenyl Cp ring. For compound (II) one of the ferrocenyl Cp rings is coplanar with the carbonyl group, the other with the double bond of the cyclopentene ring, but the CO moiety and the double bond are basically perpendicular to each other.