Photoelectron Spectroscopy of Some trans-2,2-Disubstituted Stilbenes

The He I photoelectron (PE) spectra of stilbene (1), 2,2\u27-dichlorostilbene (2) 2-amino-2\u27-chlorostilbene (3), 2,2\u27-diaminostilbene (4) ,and 2,2\u27-dinitrostilbene (5), all in their trans configuration are recorded and discussed. The electronic structure of 1-5 can well be described on the basis of the composite molecule method and simple Hiickel molecular orbital (HMO) calculations. Results indicate the importance of substituent effects causing characteristic shifts of low energy electronic band systems in the PE spectra

Photoelectron Spectroscopy of Some trans-2,2-Disubstituted Stilbenes

The He I photoelectron (PE) spectra of stilbene (1), 2,2\u27-dichlorostilbene (2) 2-amino-2\u27-chlorostilbene (3), 2,2\u27-diaminostilbene (4) ,and 2,2\u27-dinitrostilbene (5), all in their trans configuration are recorded and discussed. The electronic structure of 1-5 can well be described on the basis of the composite molecule method and simple Hiickel molecular orbital (HMO) calculations. Results indicate the importance of substituent effects causing characteristic shifts of low energy electronic band systems in the PE spectra

HeI Photoelectron Spectra of o,o’-Bridged Biphenyls by 2-X-Propylene (X = O, S, SO, NCH3) Chains

Hel photoelectron (PE) spectra of 1,11-dimethyl-5,7-dihydro-di-benzo[c,e]oxepine (1), 1,11-dimethyl-5,7-dihydro-dibenzo[c,e]thie-pine (2), 1,11-dimethyl-5,7-dihydro-dibenzo[c,e]thiepine-S-oxide(3), 1,6,11-trimethyl-6,7-dihydro-5H-dibenzo[c,e]azepine (4), and 5,11-di-methyl-4,5,6,10,11,12-hexahydro-5,11-diaza-dibenzo[ef,kl]heptalene (5) have been measured. The low energy region of the spectra has been analyzed using semiempirical PM3, AM1 and MNDO SCF MO calculations (assuming the validity of Koopmans’ theorem (Physica 1 (1934) 104) as well as empirical arguments (Franck-Condon (FC) envelopes) and correlation with PE spectra of similar molecules. Their electronic structure might be responsible for their Chemical properties

Acyclic Analogues of Purine Nucleosides with Dimethylaminoethyl and Dimethylaminoethoxyalkyl Side Chains: Preparation, One- and Two-dimensional 1H- and 13C-NMR Studies

The novel acyclic analogues of purine nucleosides containing 6-N- [2-(dimethylamino)ethyl] and 9-(2-hydroxyalkyl) substituents (6, 7), or 9-[2-(2-(dimethylamino)ethoxy)alkyl] substituent and 6-amino group, free (5) or transformed into pyrrolo moiety (11, 12), were prepared by reaction of protected 9-(2-hydroxyalkyl)adenines with 2-(dimethylamino)ethyl chloride hydrochloride. The substitution site in the purine ring was determined by 1H- and 13C-NMR, using chemical and substituent induced shifts, H-H and C-H coupling constants and connectivities in two-dimensional homo- and hetero- nuclear correlation spectra

HeI Photoelectron Spectra of o,o’-Bridged Biphenyls by 2-X-Propylene (X = O, S, SO, NCH3) Chains

Hel photoelectron (PE) spectra of 1,11-dimethyl-5,7-dihydro-di-benzo[c,e]oxepine (1), 1,11-dimethyl-5,7-dihydro-dibenzo[c,e]thie-pine (2), 1,11-dimethyl-5,7-dihydro-dibenzo[c,e]thiepine-S-oxide(3), 1,6,11-trimethyl-6,7-dihydro-5H-dibenzo[c,e]azepine (4), and 5,11-di-methyl-4,5,6,10,11,12-hexahydro-5,11-diaza-dibenzo[ef,kl]heptalene (5) have been measured. The low energy region of the spectra has been analyzed using semiempirical PM3, AM1 and MNDO SCF MO calculations (assuming the validity of Koopmans’ theorem (Physica 1 (1934) 104) as well as empirical arguments (Franck-Condon (FC) envelopes) and correlation with PE spectra of similar molecules. Their electronic structure might be responsible for their Chemical properties

Benzylidene-bis-(4-Hydroxycoumarin) and Benzopyrano- Coumarin Derivatives: Synthesis, 1H/13C-NMR Conformational and X-ray Crystal Structure Studies and In Vitro Antiviral Activity Evaluations

We report on the synthesis of 4-hydroxycoumarin dimers 1-15 bearing an aryl substituent on the central linker and fused benzopyranocoumarin derivatives 16-20 and on their in vitro broad anti-DNA and RNA virus activity evaluations. The chemical identities and structure of compounds 1-20 were deduced from their homo- and heteronuclear NMR measurements whereas the conformational properties of 5, 14 and 20 were assessed by the use of 1D difference NOE enhancements. Unequivocal proof of the stereostructure of compounds 7, 9, 16 and 18 was obtained by single crystal X-ray diffraction method. The X-ray crystal structure analysis revealed that two 4-hydroxycoumarin moieties in the 4-trifluoromethylphenyl- and 2-nitrophenyl derivatives (compounds 7 and 9, respectively) are intramolecularly hydrogen-bonded between hydroxyl and carbonyl oxygen atoms. Consequently, the compounds 7 and 9 adopt conformations in which two 4-hydroxycoumarin moieties are anti-disposed. Antiviral activity evaluation results indicated that the 4-bromobenzylidene derivative of bis-(4-hydroxycoumarin) (compound 3) possesses inhibitory activity against HSV-1 (KOS), HSV-2 (G), vaccinia virus and HSV-1 TK- KOS (ACVr) at a concentration of 9-12 mM and at a minimum cytotoxic concentration (MCC) greater than 20 M. Compounds 4-6, 8, and 20 were active against feline herpes virus (50% effective concentration, EC50 = 5-8.1 M), that is at a 4-7-fold lower concentration than the MCC

Hydantoin derivatives of L- and D-amino acids: synthesis, antiviral and antitumoral activity evaluations

3, 5-Disubstituted hydantoin (1, 3-imidazolidinedione) derivatives 5a-h were prepared by base induced cyclization of the corresponding N-(1-benzotriazolecarbonyl)-L- and D-amino acid amides 4a-h. Compounds 5a-h were evaluated for their cytostatic and antiviral activities. Among all the compounds evaluated, 3-benzhydryl-5-isopropyl hydantoin (5a) showed a weak but selective inhibitory effect against vaccinia virus (EC50 = 16 g/mL ; selectivity index: 25). 3-Cyclohexyl-5-phenyl hydantoin (5g) showed inhibitory activity against cervical carcinoma (HeLa, IC50 = 5.4 M) and breast carcinoma (MCF-7, IC50 = 2 M), but also cytotoxic effects towards human normal fibroblasts (WI 38). On the contrary, the 3-benzhydryl-5-phenyl substituted hydantoin derivative 5h showed moderate inhibitory activity towards HeLa, MCF-7, pancreatic carcinoma (MiaPaCa-2), lung carcinoma (H 460) and colon carcinoma (SW 620) (IC50 = 20 23 M), but no effect on WI 38

Merocyanine Isomers of Spiro[indolino-indolopyrans]: 1H and 13C NMRand X-ray Crystal Structure Study

The synthesis of stable merocyanine isomers 4 and 5 of the corresponding spiro[indolino-indolopyrans] is described. The structure of 4 and 5 was deduced on the basis of their lH and 13C NMR spectra. Geometrical data from X-ray structure analysis show that indolo and indolino rings in 4 are coplanar with the central diene bridge. The bond length shortening of the central single bond and the heterocyclic moieties indicate an electron delocalization over the whole molecule

New Acyclic Purine Nucleoside Analogues Containing Exocyclic Pyrrolo Moiety: Synthetic, NMR and X-ray Crystal Structure Studies

The synthesis of novel 6-(N-pyrrolyl)purine nucleoside analogues containing acyclic side chains attached to the purine ring at N-9 is described. The structures were determined by 1H and 13CNMR on the basis of chemical shifts, substituent induced shifts, C-H coupling constants and connectivity in the COSY,NOESY and HETCOR spectra. Unequivocal proof for the stereostructure of 6 was obtained by its X-ray crystallographic analysis. Geometrical data from X-ray structural analysis showed that the two 6-(N-pyrrolyl) purine rings involved in the skeleton of 6 are anti-disposed but not centrosymmetric with respect to the central aliphatic bridge

Antitumor mechanisms of amino acid hydroxyurea derivatives in the metastatic colon cancer model

The paper presents a detailed study of the biological effects of two amino acid hydroxyurea derivatives – that showed selective antiproliferative effects in vitro on the growth of human tumor cell line SW620. Tested compounds induced cell cycle perturbations and apoptosis. Proteins were identified by proteomics analyses using two-dimensional gel electrophoresis coupled to mass spectrometry, which provided a complete insight into the most probable mechanism of action on the protein level. Molecular targets for tested compounds were analyzed by cheminformatics tools. Zinc-dependent histone deacetylases were identified as potential targets responsible for the observed antiproliferative effect