Synthesis of 1,8-naphthyridine derivatives. Potential antihypertensive agents. 1

Reaction of substituted 7-chloro-1,8-naphthyridines with N-carbethoxypiperazine gave in good yields the corresponding 7-(4-carbethoxypiperazin-1-yl)-1,8-naphthyridines V as potential antihypertensive agents.     

Synthesis of a novel tripodal receptor based on 1,8-naphthyridine derivatives

<正>A novel tripodal receptor,1,3,5-tri((5,7-dimethyl-1,8-naphthyridin-2-yl-amino)methyl)-2,4,6-triethylbenzene(1) was synthesized from starting materials 2,6-diamino-pyridine(2) and 1,3,5-triethylbenzene(4) by three steps with an overall yield of 25%,and characterized by ESI-MS,FT-IR and ~1H NMR spectra.Additionally,its absorption and emission spectra were investigated.     

Synthesis of fused derivatives of 1,8-naphthyridine

Reactions of aromatic aldehyde, 2-aminoprop-1-ene-1,1,3-tricarbonitrile and cyclic enhydrazinoketones led to the formation of N-substituted 5-aryl-2,4-diamino-6-oxo-5,6,7,8,9,10-hexahydrobenzo[b][1,8]- naphthyridine-3-carbonitriles     

Synthesis and insecticidal activities of 1,8-naphthyridine derivatives

1,8-Naphthyridines (NAP) are biological important scaffolds in bioactive molecules design. By hybrid of NAP with neonicotinoid core structure, nine novel NAP derivatives were synthesized and subjected to insecticidal activities evaluation. Some of the compounds showed excellent insecticidal activity against cowpea aphids (Aphis craccivora) with LC₅₀ values ranging from 0.011 mmol/L to 0.067 mmol/L. The results indicated that 1,8- naphthyridine can be used as insecticidal structure for further modification.     

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.     

An intramolecular cyclization of 7-substituted 6-fluoro- 1,8-naphthyridine and -quinoline derivatives

A synthesis of 1,4-oxazine and pyrazine ring systems by an intramolecular cyclization of 7-substituted 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine and -quinoline derivatives having a nitrogen or oxygen nucleophilic site in the C-7 appendage was studied. The in vitro antibacterial activities of compounds prepared by this method were tested.     

Synthesis and evaluation of fluorogenic 2-amino-1,8-naphthyridine derivatives for the detection of bacteria

Several novel fluorogenic N-aminoacylnaphthyridine substrates were synthesized in good yield and tested for their ability to detect pathogenic bacteria in agar-based cell culture. Simple 2-N-(β-alanyl)amino-5,7-dialkylnaphthyridine substrates were selectively hydrolysed by β-alanylaminopeptidase expressing bacteria, but were subject to diffusion in the agar medium. Diffusion was reduced in the 2-N-(β-alanyl)amino-7-alkylnaphthyridine substrates with longer alkyl chains, but inhibition of growth was increased. 2-N-(β-Alanyl)amino-7-octylnaphthyridine inhibited the growth of all species tested, except for strains resistant to colistin/polymyxin, providing a rationale for the development of substrates for the selective detection of drug resistant species in clinical samples.     

Cationic corrole derivatives: a new family of G-quadruplex inducing and stabilizing ligands

Water-soluble cationic corrole derivatives were designed and synthesized, and the first observation of their interactions with the telomeric G-quadruplex was made.     

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.     

Preparation of hexafluoro-1,8- and -2,7-naphthyridine

Hexachloro-1,8- and -2,7-naphthyridine have been prepared from 2,7-dichloro-1,8-naphthyridine and 1,3,6,8-tetrachloro-2,7- naphthyridine respectively. From these products and their starting materials a series of partially and totally fluorine substituted compounds have been derived.     

A three-component,one-pot synthesis of 1,8-naphthyridine and isoxazole derivatives and computational elucidation of the mechanism

Research on Chemical Intermediates - An efficient and general method for the synthesis of substituted 3,4-dimethylisoxazolo[5,4-b]pyridine-5-carboxamide and benzo[b][1,8]naphthyridine-3-carboxamide...     

Pd（OAc）2 catalyzed synthesis of heteroaryl-substituted 1,8-naphthyridine derivatives via C-N-coupling reactions of chloronaphthyridines

An efficient route to synthesize the heteroaryl-substituted 1,8-naphthyridine derivatives was described.Eight 2-heteroaryl-and 2,7-diheteroaryl-1,8-naphthyridine derivatives were obtained through palladium-catalyzed C-N-coupling reactions of chloro-naphthyridines with imidazole,benzimidazole,morpholine,3,5-dimethylpyrazole,and phthalimide in moderate to good yields.     

Eco-friendly synthesis of 1,8-naphthyridine 5-aryl-1,3,4-oxadiazole derivatives under solvent-free solid-state conditions and their antimicrobial activity

Research on Chemical Intermediates - A simple and highly efficient green synthetic procedure has been described for the construction of...     

Selective acetylation of substituted (E)-4(1H)-hydroxyimino-2,3-dihydro-1,8-naphthyridine

We report a selective acetylation of compounds 2 in 1-, 4- or 1,4-position. The treatment of 2 with acetic anhydride gave the compounds 3 and with acetyl chloride the compounds 4 . The 1-acetyl derivatives were obtained starting from 5 via the oxime derivatives 6, 7 and 8 . Tests on phytoiatric antimycotic activity and on reactivation of phosphylated acetylcholinesterase and inhibition of acetylcholinesterase were performed.     

Paramagnetic derivatives of, 6-naphthyridine

Conclusions Some stable nitroxyl radicals of the 2,2,6,6-tetramethylpiperidine series, namely 2-aryl(heteryl)-5-oxyl-5,5,7,7-tetramethyl-5,6,7,8 -tetrahydro-1,6-naphthyridines, were obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2822–2825, December, 1977.     

Electrochemical investigation on the interaction of benzene sulfonyl 5-fluorouracil derivatives with double-stranded DNA and G-quadruplex DNA

The interaction of double-stranded(ds) and G-quadruplex(G4) DNA with sulfonyl 5-fluorouracil derivatives(5-fluoro-1-(arylsulfonyl) pyrimidine-2,4(1H,3H)-diones) was investigated in this research,in which Au electrodes modified with ds-DNA or G4-DNAs were used as a working electrode.The investigation showed that the binding affinity with G4-DNA was significantly increased when 5-fluorouracil(5-FU) was modified with arylsulfonyl groups.The presence of strong electron-withdrawing groups on benzene sulfonyl 5-FU greatly enhanced the binding selectivity(k G4-DNA /k ds-DNA).Such results provided new insights into the potential connections between the chemical structure of drug candidates and their anticancer activities.     

电化学法研究苯磺酰类5-氟尿嘧啶衍生物与双链和G-四链DNA的相互作用

本文以自组装法制得的双链DNA（ds．DNA）和G-四链体DNA（G4-DNA）修饰的金电极为工作电极,以Fe（CN）63-／4-为电活性指示剂,采用循环伏安法和微分脉冲伏安法研究了非电活性苯磺酰类5-氟尿嘧啶衍生物与ds-DNA和G4．DNA的相互作用．实验结果表明：苯磺酰类5-氟尿嘧啶与ds-DNA或G4．DNA的结合常数与苯环上邻、对位取代基的得失电子能力密切相关,强吸电子基团取代有利于苯磺酰类5-氟尿嘧啶选择性结合G-四链体DNA．     

Palladium(II) complexes based on 1,8-naphthyridine functionalized N-heterocyclic carbenes (NHC) and their catalytic activity

Palladium complexes containing 2,7-bis(mesitylimidazolylidenyl)naphthyridine (NHC-NP) have been synthesized and characterized. Reaction of [{Ag(3)(NHC-NP)(2)}(PF(6))(3)] with [Pd(PhCN)(2)Cl(2)] provided an unusual dipalladium complex bridged by two NHC-NP units, forming a 20-membered dinuclear metallacycle [{Pd(2)(NHC-NP)(2)Cl(2)}(PF(6))] (2) in high yield. Treatment of 2 with KI in acetone yielded a neutral species [Pd(2)(NHC-NP)I(4)] (3). Meanwhile, the pyridinyl N-heterocyclic carbene (NHC-Py) precursor, 1-(2-pyridinyl)-3-mesitylimidazolium chloride, reacted with Pd(2)(dba)(3) directly to form the mononuclear palladium complex [Pd(NHC-Py)Cl(2)] (4). These complexes were characterized by elemental analyses as well as NMR spectroscopy, and the structures of 3 and 4 were further identified by X-ray diffraction analysis. The use of these palladium complexes for Suzuki-Miyaura and Kumada-Corriu coupling reactions has been examined. There is no significant difference in catalytic activities between 2 and 4 in Suzuki-Miyaura coupling reactions. However, the catalytic activity of 2 in the Kumada-Corriu coupling of ArBr with cyclohexylmagnesium bromide is quite different from that of 4. Thus complex 2 is active for the cross coupling, but complex 4 is active for the reduction of aryl halides.     

Protonation of 1, 5-naphthyridine derivatives

The direction of protonation (1-N or 5-N) or 2-, 2,3-, and 2,6-substituted derivatives of 1,5-naphthyridine was determined on the basis of the basicity constants.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 965–968, July, 1977.