COMPLEXES OF 1,8-NAPHTHYRIDINES IX. GROUP VIb METAL CARBONYL COMPLEXES CONTAINING 1,8-NAPHTHYRIDINE, 2-METHYL-1,8-NAPHTHYRIDINE OR trans-DECAHYDRO-1,8-NAPHTHYRIDINE

Abstract

Complexes of the type M(CO)₅(N-N), M(CO)₄(N-N) and M(CO)₃(N-N)₂, where M is Cr, Mo or W and N-N is 1,8-naphthyridine(napy), 2-methyl-1,8-naphthyridine(2-mnapy) or trans-decahydro-1,8-naphthyridine(dhnapy), have been prepared and characterized by infrared and proton magnetic spectroscopy. Complexes of the type Mo(CO)₃(N-N)(napy), where N-N is 1,10-phenanthroline(phen), 2,2′-bipyridine(bipy), 2,9-dimethyl-1,10-phenanthroline(2,9-dmphen) or 2,7-dimethyl-1,8-naphthyridine (2,7-dmnapy), were also prepared and characterized by infrared spectroscopy. In these systems, the various naphthyridine donors exhibit the unique ability to behave as both mono- and bidentate ligands. The mode of bonding between the metal and heterocycles is determined by proton magnetic resonance data.     

1,8-Pyrenylene-ethynylene macrocycles

A concise, highly regioselective synthesis of 1,8-dibromo-4,5-dialkoxypyrenes has been developed and exploited in the synthesis of some 1,8-pyrenylene-ethynylene macrocycles. The (1)H NMR data and NICS calculations indicate that there is little or no macrocyclic ring current. Concentration-dependent UV-visible studies indicate no aggregation at low concentration, but 8b forms dimers with voids suitable for intercalation of small molecules in the solid state.     

Facile synthesis of 1,8-naphthalimides in palladium-catalysed aminocarbonylation of 1,8-diiodo-naphthalene

1,8-Diiodo-naphthalene was aminocarbonylated with various primary and secondary amines in the presence of palladium(0) complexes formed in situ from palladium(II) acetate and triphenylphosphine. In the case of primary amines, depending on the amine to substrate ratio, two types of products have been obtained in highly chemoselective reaction: dicarboxamides and N-substituted imides have been formed at high and low amine to substrate ratio, respectively. The reaction tolerates the ester functionality, so that amino acid esters could serve as N-nucleophiles and in this way, naphthalimides possessing stereogenic centre in the N-substituent could be synthesised.     

Dimers of 1,8a-Dihydro-1,8-Naphthyridine Derivatives as Models of Chiral Self-Recognition

A theoretical study of the dimer formation of chiral 1,8a-dihydro-1,8-naphthyridine derivatives has been carried out by means of DFT calculations. In the cases treated, the heterochiral dimers (RS or SR) are always more stable than the homochiral ones (RR or SS). Two possible proton transfer processes have been studied, the concerted and the non-concerted ones. The non-concerted TS corresponds to a true TS while the concerted one presents two imaginary frequencies. The geometrical characteristics of the hydrogen bonds in all the structures calculated have been correlated using the Steiner–Limbach model.     

Competitive One-Pot Reactions: Simultaneous Synthesis of Decahydroacridine-1,8-diones and 1,8-Dioxo-octahydroxanthenes and Photophysical Characterization

A simple and convenient one-pot method for simultaneously obtaining decahydroacridine-1,8-diones and 1,8-dioxo-octahydroxanthene derivatives is described. A high conversion yielding both products was obtained under the reaction conditions. To understand the optical behavior of the model compounds and their potential use as antenna moieties in bichromophoric systems, the photophysical properties of all samples were studied using ultraviolet–visible absorption and steady-state fluorescence spectroscopy in methanol solutions. For the case of the acridinediones, the fluorescence spectra were found to exhibit the typical emission profile of the locally excited state, whereas, contrary to previous published experimental results, reliable fluorescence emission spectra for the xanthenes derivatives could not be obtained. On the other hand, the poor quantum yields of the synthesized decahydroacridine-1,8-diones were explained based on the benzene-like substitution effect, which favors the intersystem crossing relaxation mechanism.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

2,3-Fused 1,8-Naphthyridines

The Friedlander condensation of 2-aminonicotinaldehyde with cyclic ketones leads to the preparation of 2,3-fused 1,8-naphthyridines. The spectral properties and basicities of these molecules are discussed.     

Transformations of sym-octahydroxanthene-1,8-diones and 1,8-dioxo-sym-octahydroxanthylium salts in recyclization under the influence of amines

The chemical behavior of 9-R-sym-octahydroxanthene-1,8-diones and salts based on them in recyclization reactions under the influence of amines was studied. The effect of the basicity of the amines on the direction of recyclization was established. A method is proposed for the single-stage synthesis of sym-octahydroacridine-1.8-dione oximes based on 1,8-dioxo-sym-octahydroxanthenes. Conditions were worked out for the oxidation of sym-octahydroxanthene-1,8-diones and N-R-decahydroacridinediones to the corresponding salts. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 32–38, January, 2006.     

Polyamides from trans-4-octen-1,8-dioic and trans-2-trans-6-octadien-1,8-dioic acids

Novel polyamides from trans-4-octen-1,8-dioic acid (4-OD) and trans-2-trans-6-octadien-1,8-dioic acid (2,6-ODD) ad linear aliphatic diamines or piperazine were prepared in good yields by low-temperature polycondensation. The polymers obtained were investigated by infrared spectroscopy, x-ray diffraction, and differential scanning calorimetry. Polyamides from 4-OD show high molecular weights and crystallinities and T_m above 500°K, whereas those from 2,6-ODD are very weakly crystalline and decompose without melting in nitrogen at temperatures higher than 550°K. DSC studies revealed in the case of 4-OD polymers with odd diamines, a multiple peak phenomenon in the melting region, strongly dependent from the heating rate. Some hypotheses consistent with this behavior are briefly discussed, and it is concluded that the phenomenon arises from melt recrystallization occurring during the DSC scan.     

Some derivatives of 1,8-naphthyridine, 1,2-dihydropyrindo[2,3-B][1,8]-naphtyridine and 2H-pyrano[2,3-b][1,8]naphtyridine

The pyrolysis of antipyrine 4dizaonium flouroborate gave an antipyrylazopyrazopyrazolone instead of the desired 4-fluoroantipyrine. This compound was formed by intermolecular and intramolecular coupling of the diazo compound at elevated temperatures.     

Structure of monomers of bis-(1,8-naphthylene)dichlorodisilane and bis-(1,8-naphthylene)dichlorodisiloxane

Journal of Structural Chemistry -     

Synthesis and fluorescence of N-substituted-1,8-naphthalimides

A number of novel N-substituted-1,8-naphthalimides have been prepared and their fluorescence yields measured in water at pH 7.4. The type of substitutent and the substitution pattern on the naphthalimide nucleus produce markedly different fluorescence yields, (quantum efficiencies, ø varying from ø = 0-0037 for N-(3-N'-morpholino-1-propyl)-4-amino-3-methoxy-1,8-naphthalirnide (7) to ø = 0–77 for N-(3-bromopropyl)-4-acetamido-1,8-naphthalimide (31).     

1,8-Naphthyridines. Part I. Synthesis of some trifluoromethyl-1,8-naphthyridine derivatives

The synthesis of some 2-amino-1,8-naphthyridine derivatives substituted in the 5- and/or 7-positions with trifluoromethyl is described along with their conversions to the corresponding 1,8-naphthyridin-2(1H)ones. A modified procedure for oxidizing electron-deficient heterocyclic compounds to their N-oxides is presented.     

Advances in 1,8-Naphthyridines Chemistry

This review reports a broad overview of the synthetic procedures of 1,8-naphthyridines, dibenzo[b,g][1,8]naphthyridine, dibenzo[c,f][1,8]naphthyridine, 1,8-naphthyridine-3-carboxylic acid, 1,8-naphthyridine-3-carboxamide, and 1,8-naphthyridine-3-carbohydrazide compounds and their reactions. The physical properties, spectral data, and biological importance of naphthyridines are discussed.