Non-covalent interactions play a key role in many areas of modern chemistry, especially in the field of supramolecular chemistry. In particular, interactions involving aromatic rings are key processes in both chemical and biological recognition. Interactions involving p systems are widely used in supramolecular chemistry and they are very important binding forces that determine the packing of organic molecules in crystals. On the other hand, the presence of cation···p interactions is also crucial for the characteristics and stability of proteins. As already known, certain amino acids have aromatic groups in their side chains, which would allow their interaction with cations present in the environment. Furthermore, considering that other amino acids have protonated groups in their side chains, is more than likely for cation···p contacts to occur in a protein involving side chains of amino acids. Aromatic chains of phenylalanine, tyrosine and tryptophan may act therefore as important binding sites for cations. In this work a study of the interaction in M⁺···p···p systems formed by the combination of two aromatic rings and a cation has been carried out. In order to gather more information about the nature of the interaction an energy decomposition analysis has been carried out by means of the Local Molecular Orbital- Energy Decomposition Analysis (LMO-EDA) approach, the energy being divided in electrostatic, repulsion, induction and dispersion contributions. The interacting units have been chosen as to represent the side chain of different amino acids. Therefore, benzene, phenol and indole have been considered as aromatic moieties, whereas the cationic unit is guanidinium in order to model the side chain of arginine.

For the DA reactions between nitropyrroles derivatives and isoprene, the combination of microwave irradiation and protic ionic liquids, has a notable synergistic effect

Abstract: Piperidin(on)es represent the core unit of a wide range of alkaloids and biologically active compounds and in particular, 6-(het)aryl substituted compounds play an important role as key targets for the pharmaceutical industry. The stereocontrol of carbon centers embedded in the azaheterocycle is a permanent synthetic task for organic chemists. In this regard we have developed two alternative and conceptually new synthetic approaches to a variety of 6-arylated piperidinones that is based upon the asymmetric reduction of endocyclic enamides readily accessible from imides, as the key step. The stereoselectivity of the reduction process could be controlled either by the use of a (S)-methylprolinol chiral auxiliary (Z = SMP, path a) or by ligand/catalyst chirality transfer (Z = Bn, path b). Varying degrees of success were observed for these conceptually different approaches.

Thermolysis of 2-azidobenzophenone includes interaction between azido and carbonyl group resulting in 1,3-dipolar cyclization without nitrene intermediate formation. The reaction gives high yields of of 3-phenylanthranil. Photolysis of 2-azidobenzophenone as well as other aromatic azides gives singlet nitrenes as decomposition products. Small singlet-triplet gap reduces partly triplet forbiddance, and transition from the singlet into triplet state becames possible by means of intersystem crossing. Thus, two highly reactivie intermediates are formed under photolysis of the azide. They determine the subsequent reactions. The singlet nitrene can insert into carbonyl group giving 3-phenylanthranil, and the triplet nitrene can dimerize to form azocompound or abstract an hydrogen atom from solvent to turn into amines. In the 2-azidobenzophenone photolysis in acetonitrile we have found high yields of 3-phenylanthranil. The scheme becomes complicated by the 3-phenylanthranil secondary decomposition. No azocompound was found. We have proposed that there has place a transition of nitrene into low reactive conjugated biradical having electron density localized on nitrogen atom of nitrene and oxygen atom of carbonyl group. The biradical gives 3-phenylanthranil after of introsystem crossing into the singlet state.

We have studied the Copper (II) Salt-Mediated Reaction of nucleophilic substitution of the azide group of acyl azide by secondary amine group. In the course of the reaction copper (II) azide, acetic acid and the corresponding amide are formed. On the basis of IR spectra of reaction products we have concluded that there is the absorption band shifts of the stretching vibrations of azide group, which explains the formation of an intermediate complex with copper (II) acetate. Characteristic to the Copper (II) acetate blue-green color of the solution changes to brown color of the Copper (II) azide solution. It can be used as a characteristic "color" or a quantitative test, to determine amount of acyl azide and the secondary aliphatic amines.

We have performed simulation of reactions of nitroso- and nitrosocompounds with sulfur oxides by means of UB3Lyp/6-31g+(d) method. Gaussian 03w was used as basic programm.QST2 and QST3 methods implemented in Gaussian 03 w programm were used to find transition states for the reactions. We have proved that nitroso oxides are produced in the course of the reactions. The energetically preferable reactions procede in the triple state. The energy parameters were determined for every reaction involved. the realibility of the transitional state obtained were confirmed by both presence of the only one imaginary frequency for the structure and by IRC procedure.

Over the years, sulfones have emerged as interesting synthetic goals because they are valuable intermediates in organic synthesis¹ as well as important building blocks in biologically active compounds.² The usual procedures for their preparation are the oxidation of the corresponding sulfides and the sulfonylation of suitable arenes.³ Nevertheless, their scope of application is limited by the availability of sulfides and by the substituent-directing effects and the reactivity substrate requirements, respectively. On the other hand, the metal-mediated cross-coupling reactions between sulfinic acid salts and aryl derivatives (halides and triflates) are milder alternatives, although they imply the use of air or moisture sensitive reagents.⁴ In recent years, we have focused on arylstannanes as valuable and easily accessible reagents in C-C bond forming reactions through catalyst-free processes.⁵ Driven by these results and considering the importance of sulfones we initiated studies on the reaction of arylstannanes with sulfonyl chlorides. Now, we report the synthetic potential of this pair of reagents, under catalyst-free conditions, for the generation of asymmetric diarylsulfones, and its efficiency using diarylstannanes as starting substrates. Moreover, a special work up is carried out in order to recover the di- and trialkyltin chlorides generated. All the reactions studied went, exclusively, through an ipso-substitution and give acceptable yields of sulfones from aryl sulfonyl chlorides supporting either electron-releasing or electron-attracting substituents. ¹ P.R. Blakemore, J. Chem. Soc. Perkin Trans. 1 2002, 2563. ² a) R.C. Bernotas et al. Bioorganic & Medicinal Chemistry Letters 2010, 20, 209. b) S.A. Kolodziej et al. Bioorganic & Medicinal Chemistry Letters 2010, 20, 3561. ³ (a) M. Rahimizadeh et al. J. Mol. Catal. A: Chem. 2010, 323, 59. (b) A. Rostami et al. Tetrahedron Lett. 2010, 51, 3501. (c) S. Nara et al. J. Org. Chem. 2001, 66, 8616. ⁴ (a) D.C.Reeves et al. Tetrahedron Lett. 2009, 50, 3501. (b) K. Anirban et al. Org. Lett. 2007, 9, 3405. ⁵ (a) M.J.Lo Fiego et al. J. Org. Chem.2011, 76, 1707. (b) M.J. Lo Fiego et al. J.Organometal.Chem. 2009, 694, 3674. (c) M.J. Lo Fiego J. Org. Chem. 2008, 73, 9184. (d) G.F. Silbestri et al. J. Organometal. Chem. 2006, 691, 1520.

Microorganisms have always been regarded as a treasure source of useful enzymes. During the last twenty years, biochemical reactions performed by microorganisms or catalyzed by microbial enzymes have been extensively evaluated. This investigation aims at selection of chtinase producing bacterial sp. on colloidal chitin agar medium from soils and isolation of intracellular enzyme for therapeutic purpose. Total 9 isolates was recovered ,purified and after screening the bacterial isolate chit S6 was selected and Ammonium sulfate crystallized, dialysed intracellular enzyme chitS6 used for chemotherapeutic activity against pathogenic fungi Aspergillus niger Chitin consists of β-1, 4-linked N-acetylglucosamine residues that are arranged in antiparallel (α), parallel (β), or mixed (γ) strands, with the α-configuration being the most abundant. The degree of deacetylation also varies from 0 to 100% (chitosan). Except for the β -chitin of diatoms (chitan), chitin is always found crosslinked to other structural components, such as proteins and glucans. The selected and purified strain of the isolate chit S6 were further diluted to 10^-1 , 10^-3 ,10^-5 and 0.1 ml of these dilutions are plated by spread plate technique on NA medium. These plates were incubated at 27⁰ C .The Visual Examination Was Carried Out at intervals of seven days Up to 38^th day. The work shows potential use of chitinase producing bacterial sp. Such as chit S6 as an antifungal agent.

There is considerable interest in the synthesis of optically active cyclic amino alcohols since many representatives have been reported to exhibit diverse, strong physiological effects. One of these classes of compounds are 2-alkyl- and 2-aryl- 3-hydroxypyrrolidines. Representative examples are the antibiotic preussin the hypertensive alkaloid codonopsine and the antibiotic anisomycin. Here we would like to present an effective synthesis of 2-(2-aryletyl)-3-hydroxypyrrolidines and their derivatives based on our non-classical Wittig reaction of the 5-aryl substituted 2-aminobutane-4-lactones yielding enantiomerically pure substituted 3a,4-dihydro-2H-furo[3,2-b]pyrrol-5(3H)-ones. (Synlett 2011, 1631-1637.) Subsequent reductive treatment of such bicyclic tetramic acid analogues has opened the door towards methylene homologues of 4-deoxyanisomycins or extrapolated l-phenylalanylamides – methylene homologues of substances with potential anti-HIV activity. (J. Chem. Soc. - Perkin Trans. 1 2001, 1421-1430.)

A straightforward preparation of enantiomerically highly enriched N-substituted (S)-4-(ethylsulfanyl)benzoylalanine will be presented. This process involves the tandem of crystallization-induced asymmetric transformation (CIAT) with conjugate addition of N-nucleophiles to the corresponding aroylacrylic acids and their oxidized analogs. Further transformations to (S)-4-(ethylsulfanyl)benzoylalanine, (S)-4-(ethylsulfoxide)benzoylalanine and (S)-4-(ethylsulfonyl)benzoylalanine via periodate oxidation are also described. The targeted amino acid (S)-4-(ethylsulfonyl)benzoylalanine (S)-ESBA is the first selective kynurenine aminotransferase (KAT II) inhibitor.