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.     

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.     

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.     

The Plausible Aromaticity of 1,8-Naphthalimides: The Enthalpy of Formation of N-Methyl-1,8-Naphthalimide

In order to understand the aromaticity of 1,8-naphthalimides, the enthalpies of combustion and sublimation of N-methyl-1,8-naphthalimide were determined. The numerical values are –6095.8 ± 3.5 and 109.7 ± 0.8 kJ · mol^–1. The enthalpies of formation of condensed and gas phase N-methyl-1,8-naphthalimide are accordingly –306.1 ± 3.9 and –196.4 ± 4.0 kJ · mol^–1. It is deduced that naphthalimides enjoy some 40 kJ · mol^–1 of aromatic stabilization over that of the maleimides, shown to be nominally destabilized and modestly antiaromatic in our recently published thermochemical study.     

1,8-二羟基-9,10-二氢蒽的合成

以1,8-二羟基蒽醌为原料,经甲醚化,锌粉和金属钠还原,去甲基等4步反应合成1,8-二羟基-9,10-二氢蒽,总产率为37.1,8-二甲氧基蒽醌用NaBH₄/CF₃COOH还原生成二聚产物,并测定了其单晶结构.     

CHLOROSULFONATION OF 9-ARYLOCTAHYDROXANTHEN-1,8-DIONES

The 9-aryloctahydroxanthen-1,8-diones (3, 4– 24) were prepared by reaction of cyclohexan-1,3-dione (1) with selected arylaldehydes. The xanthendiones (4– 9, 11, 12, 18, 21, 22) were successfully reacted with chlorosulfonic acid, and the crude sulfonyl chlorides were converted into 15 sulfonamides (26– 40) for screening as potential pesticides. Attempted chlorosulfonation of the xanthendiones (13– 17) was unsuccessful. α-Methylcinnamaldehyde was reacted with cyclohexandione (1) to yield the corresponding xanthendione derivative (23). On the other hand, with o-methoxycinnamaldehyde an impure product formed and the p-methoxy isomer afforded the corresponding 2-arylpyran (25). The NMR spectral data of the compounds are briefly discussed.     

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.