New syntheses of condensed heterocycles from isoxazole derivatives. V. Pyrrolo[3,4-b ]pyridin-4-ones

Hydrogenolysis with Raney-Nickel or iron powder in acetic acid of 2,5-diphenyl-4-nitro-3-(3,5-R,R-4-isoxazolyl)pyrrolyl ketones, prepared by the Grignard reaction of 2,5-diphenylpyrrole and 3,5-R,R-4-isoxazolecarboxilic acid chlorides followed by nitration, afforded directly the desired 6H-pyrrolo[3,4-b ]pyridin-4-ones.     

Synthesis of some new 3-pyrazolyl-substituted-4(3H)quinazolinones

N-(1-Phenyl-3-methylpyrazol-5-yl)-o-aminobenzamide reacted with orthoesters to yield some new 3-pyrazolyl-substituted-4(3H)quinazolinones (VIIa,b,c,d). An alternative synthesis of Vllb was accomplished by reaction of acetylanthranyl with l-phenyl-3-methyl-5-aminopyrazole.     

Polycondensed nitrogen heterocycles. XXII. A new synthesis of 5,6-dihydro-7H-pyrazolo[1,5-d][1,4]benzodiazepin-6-ones

A new synthesis of 2-methyl-9-R'-10-R-5,6-dihydro-7H-pyrazolo[1,5-d][1,4]benzodiazepin-6-ones ( 4a-c ) is deserved. Reaction of ethyl hydrazinoacetate hydrochloride with 1,3-diketones 1a-c gave both 3-methyl-5-(4R'-5-R-2-nitrophenyl)pyrazol-1-yl-acetate acids ( 2a-c ) and the corresponding ethyl esters 3a-c . Reduction with the appropiate reducing agent of compounds 2a-c and 3a-c directly gave the title compounds. Compound 4a showed insecticidal properties against the house fly.     

Synthesis and solid state characterisation of mononuclear 2-benzoylpyridine N-methyl-N-phenylhydrazone palladium(II) complexes

2-Benzoylpyridine N-methyl-N-phenylhydrazone, HL, is a versatile ligand which reacts with [Pd(PhCN)2Cl2] forming the coordination compound [HLPdCl2], 1, characterized by the presence of the N(py)/N(im) chelate ring. When HL reacts with [Pd3(OAc)6] this gives rise to the orthometallated complex [LPd(OAc)],. In this case the Pd(II) environment consists of a N(py)/N(im) ring fused to the N(im)/C palladacycle and a monodentate acetate anion. Complex undergoes methatetical reactions with alkaline halides and complexes of general formula [LPdX](3: X = Cl; 4: X = Br; 5: X = I) are obtained. The molecular structures 3-5 of determined by single-crystal X-ray analysis proved the formation in all cases of mononuclear Pd(II) complexes containing a N(py)/N(im)/C terdentate ligand. As solid samples only compounds 3-5 exhibited luminescence at room temperature (lambdamax approximately 610 nm). This property, quite unusual in Pd(II) complexes, is discussed in terms of pi-pi] interactions, which are mainly responsible for the existence in the crystalline solid state of dimeric units.     

Investigations on the electronic effects of the peripheral 4'-group on 5-(4'-substituted)phenylazo-8-hydroxyquinoline ligands: zinc and aluminium complexes

A new series of 5-(4'-substituted)phenylazo-8-hydroxyquinolines (H[L-R]; R = N(CH(3))(2), C(2)H(5), n-C(4)H(9), C(CH(3))(3), H, and F, ) has been prepared and the corresponding Zn[L-R](2) (1a-6a) and Al[L-R](3) (1b-6b) complexes successfully synthesized. These compounds have been studied in order to design new molecular materials with enhanced electron transport properties. The obtained species have been extensively characterized by absorption and emission spectra and by cyclic voltammetric measurements. Experimental and computational results show that the Zn[L-N(CH(3))(2)].2H(2)O (1a) and Al[L-N(CH(3))(2)](1b) complexes only feature luminescence (at 620 and 600 nm), respectively. The unique effects, which are induced by the N=N-C(6)H(4)-N(CH(3))(2) group, are further proved by a reversible electron transfer process detected by cyclic voltammetry. These outcomes, discussed on the basis of theoretical calculations performed on the (H[L-N(CH3)2])-, H[L-N(CH3)2] and (H[L-N(CH3)(2)])+ species, suggest that metal complexes formed by 5-(4'-N,N-dimethylamino)phenylazo-8-hydroxyquinoline should be considered as electron transport materials suitable for applications in photonic devices.     

Polycondensed nitrogen heterocycles. VII. 5,6-Dihydro-7-h-pyrrolo[1,2-D]-[1,4] benzodiazepin-6-ones. A novel series of annelatcd 1,4-benzodiazepines

The synthesis of a novel class of annelated 1,4-benzodiazepinen, the 2-R-3 methyl-5,6-dihydro-7H-pyrrolo[1,2-d][1,4]benzodiazepin-6-ones (Ve-e), is described. The reaction of 2-(o-aminophenyl)-3-R-5-methylpyrroles(IIIa,b) with bromoacetyl bromide in the presence of triethylamine produced the title compounds. An alternative synthetic route was achieved by means of the reactions of 1a,b with the appropriated α-aminoacids. The catalytic reduction of IVe-e over 10% palladium on charcoal led in good to excellent yields directly to the formation of pyrrolo[1,2-d]-[1,4]benzodiazepines (Ve-e).     

Daminin, a bioactive pyrrole alkaloid from the Mediterranean sponge Axinella damicornis

The isolation and characterization of the known pyrrole alkaloid agelongine (6) and of the new natural product daminin (7), the bromine-free analogue of 6, from a specimen of the marine sponge Axinella damicornis is described. Compound 7 showed significant neuroprotective properties. Moreover, for the supply of sufficient material for future medicinal investigations, a short total synthesis of 7 was developed.     

New Cyclodextrin‐Bearing 8‐Hydroxyquinoline Ligands as Multifunctional Molecules

Recent investigations have rekindled interest in 8‐hydroxyquinolines as therapeutic agents for cancer, Alzheimer’s disease, and other neurodegenerative disorders. Three new β‐cyclodextrin conjugates of 8‐hydroxyquinolines and their copper(II) and zinc(II) complexes have been synthesized and characterized spectroscopically. In addition to improving aqueous solubility, due to the presence of the cyclodextrin moiety, the hybrid systems have interesting characteristics including antioxidant activity, and their copper(II) complexes are efficient superoxide dismutase (SOD) mimics. The ligands and their copper(II) complexes show low cytotoxicity, attributed to the presence of the cyclodextrin moiety. These compounds have potential as therapeutic agents in diseases related both to metal dyshomeostasis and oxidative stress.     

Clavaminols G-N, six new marine sphingoids from the Mediterranean ascidian Clavelina phlegraea

An exhaustive examination of the chemical constituents of the Mediterranean ascidian Clavelina phlegraea led to the isolation of clavaminols G-N (1-6), a new series of amino alcohols, which expand the family of modified marine sphingoids. Structures of the novel compounds 1-6 have been elucidated by spectroscopic analysis and chemical derivatization; bioactivities of compounds 1-6 have also been investigated and comparison of their pharmacological properties with those of previously isolated clavaminols A-F allowed us to perform an assessment of simple structure-activity relationships.