Telluroformaldehyde (H₂C=Te), silanetellone (H₂Si=Te) and germatellone (H₂Ge=Te) are novel heavy congeners of formaldehyde commonly known as telluro-ketones. Knowledge of the properties of such compounds is significant for a better understanding of the contribution of heavier main group elements in organometallic chemistry, and the ability of such ketones to form complexes of bio-organometallic importance. In 1983, telluroformaldehyde (H₂C=Te), was first stabilized by coordination to transition-metal centers but the synthesis and isolation of tellurium containing heavy ketones are still elusive. Following our interest in telluro-ketones, we reported the structures and energetics of X₂E=Te and XYE=Te (E=C and Si and X, Y=H, F, Cl, Br, I and CN) molecules, but their stabilities have always been questioned. Thus, in order to diminish the skepticism of experimental communities, thermodynamic and kinetic stabilities of the mentioned telluro-ketones have been endeavored using state-of-the-art computations. Moreover, a careful attempt has been made to study the stabilization of the E=Te double bond using bulky substituents such as 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt), 2,4,6-triisopropylphenyl (Tip) and the Lewis donor-acceptor ligands. The findings of this research work should serve as a good reference for the scrutinized novel telluro-ketones and also assist their synthesis and applications in future.

The first example of the use of ionic liquids as reaction media in the asymmetric Pd(II)-catalysed oxycarbonylation was investigated. Based on a ligand screening, the chiral box-type ligands were successfully used in the Pd(II)-promoted bicyclisation of pent-4-ene-1,3 diol (±)-1. The kinetic resolution of (±)-1 in the presence of chiral catalyst, p-benzoquinone and acetic acid in ionic liquids under carbon monoxide atmosphere afforded enantioenriched 2,6-dioxabicyclo[3.3.0]octane-3-ones (S,S)-2 (80% ee) and (R,R)-2 (57% ee), respectively.

The reaction of 1-cyanoacetyl-3,5-dimethylpyrazole with 2-cyanoacrylamides in the presence of triethylamine leads to triethylammonium 3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-olates (salts of Guareshi imides). The latter reacted with primary amines RNH₂ and excessive HCHO to give triethylammonium salts of 7-R-2,4-dioxo-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarbonitriles. When treated with HCl or alkyl halides, the salts afforded corresponding 3-R- or 3,7-disubstituted bispidines.

The previously unknown 5-benzoyl-3-cyano-6-phenylpyridine-2(1H)-thione was obtained by reaction of cyanothioacetamide with 2-ethoxymethylene-1,3-diphenylpropane-1,3-dione. Depending on the conditions, the thione can be alkylated to give 2-alkylthio-5-benzoyl-3-cyano-6-phenylpyridines and 2-R-3-amino-5-benzoyl-6-phenylthieno[2,3-b]pyridines. The latter also can be obtained by Thorpe-Ziegler cyclization of 2-alkylthio-5-benzoyl-3-cyano-6-phenylpyridines.

Through last decades tuberculosis has been becoming more and more dangerous ever before. Although the number of new cases has been falling since 2006, new epidemiological problem has appeared with mycobacterial stems, which are becoming increasingly resistant to current treatment, and with more frequent HIV co-infection. All these consequences lead to effort to invent highly effective and innovative drugs. ^[1] One of the first-line antituberculotic drugs is pyrazinamide (PZA). This small molecule together with its unique chemical properties is very good template and is suitable for another modifications. Two series of PZA derivatives were prepared in this research project. Two starting compounds (3-chloropyrazine-2-carboxamide and 5-chloro-6-methylpyrazine-2,3-dicarbonitrile) were treated with a various group of on-ring substituted benzylamines. All the reactions took place in microwave reactor with focused field due to higher yields and shorter reaction time (experimentally verified). Products of these aminodehalogenational reactions were chemically characterized (melting point, IR and ¹H, ¹³C NMR spectra, log P and elemental analysis) and then in vitro biological screenings were carried out. Antimycobacterial evaluation was completed using pyrazinamide and isoniazide as standards against various Mycobacterium species. Next screening was testing the herbicidal activity of prepared compounds. ^[2] The principle is measuring the inhibition of photosynthetic electron transport in spinach chloroplasts (Spinacia oleracea L.) using Hill reaction. DCMU (Diurone^®) was taken as a standard and inhibition concentration (IC₅₀) was determined. An experiment with artificial electron donor 1,5-diphenylcarbazide was performed for determining the site of action of the studied compounds in photosynthetic apparatus. Fluorescence measurements were also used to monitor the interaction of pyrazine derivatives with residues of aromatic amino acids present in the photosynthetic apparatus proteins. The major part of substances showed good herbicidal activity and there is a possibility of prediction structure-activity relationships (SAR) according to lipophilicity (π) and electronic properties (σ). The last screening included antibacterial and antifungal tests against eight antibacterial and eight fungal stems. Standards – neomycin, bacitracin, penicillin G, ciprofloxacin, phenoxymethylpenicillin, amphotericin B, voriconazole, nystatin, fluconazole. Minimal inhibition concentration (MIC) was determined as IC₉₀. Few substances have shown small activity against various tested stems but it is not enough to predict SAR. References: [1] Progress, WHO Global Tuberculosis Control Report 2011, WHO/HTM/TB/2011.16, http://www.who.int/tb/publications/global_report/2011/gtbr11_full.pdf, accessed October 3, 2012. [2] Dolezal, M.; Kralova, K. Synthesis and Evaluation of Pyrazine Derivatives with Herbicidal Activity, Herbicides, Theory and Applications, Sonia Soloneski and Marcelo L. Larramendy (Ed.), 2011, ISBN: 978-953-307-975-2, InTech

There is a wide variety of natural and synthetic benzophenones with antibacterial activity. In previous studies,[1] we reported the synthesis of substituted diarylmethanes under Barbier conditions by Stille coupling as precursors of substituted benzophenones. Catalyzed bond formation require hours to days to complete when conventional heating is used, under inert atmosphere. Microwaves have demonstrated that the reaction rate improves significantly and allows use closed vials without inert atmosphere.[2] The Stille coupling was one of the first reactions where the assistance of microwave was applied since some organotin compound have poor reactivity and, consequently, low yield of the desired product. We present here the study of the synthesis of diarylmethanes through Stille reaction under microwave irradiation, comparing the results with and without catalytic conditions and ligands,[3] based on the optimal results applying microwaves without catalyst that have been reported for Suzuki and Sonogashira coupling.[4]^,[5] In most cases, reactions were completed in short time and no homocoupling product was observed. Although reaction times are slightly higher and the yields were lower than those found in catalyzed condition, the fact that in this case this difficult type of reaction (Csp³-Csp² coupling) can be performed without catalyst, is very promising and encourages us to continue with future studies in order to find the best conditions. [1] Ocampo, R.A, Koll, L.C, Mandolesi, S.D. Ultrasonics Sonochemistry, Article in press. http://dx.doi.org/10.1016/j.ultsonch.2012.06.014 [2] a) Larhed, M. , Moberg, C., Hallberg, A. Acc. Chem. Res. 2002, 35, 717. b) Olofsson, K., Larhed, M. (Eds.: P. Lidstrum, J.P. Tierney), Blackwell, Oxford, 2004, Chap. 2 [3] a) Larhed, M., Lindeberg, G., Hallberg, A., Tetraheron Lett, 1996, 37, 8219. b) Berthault A., Berteina-Raboin, S., Finaru A., Guillaumet, G., QSAR Comb Sci, 2004, 23, 850 [4] Leadbeater, N.E., Marco, M. J. Org. Chem. 2003, 68, 5660 [5] Leadbeater, N.E., Marco, M., Tominack, B. Org. Lett. 2003, 5, 3919

The synthesis of iminosugars is one of the most active fields in synthetic organic chemistry. Due to the structural resemblance to sugars, these unique molecules have a tremendous potential in biological functions mediated by carbohydrates and have been postulated in the control of diabetes, Gaucher\'s disease, cancer, HIV, and viral infections like influenza. A survey of the literature reveals that the synthesis of 2,3,5-substituted pyrrolidines is not a trivial task specially when the attainment of enantiomerically pure compounds are requested. In this work, we describe the synthesis of enantiomerically pure poly(hydroxymethyl)pyrrolidines (iminosugars) and different routes to selective functionalization of –OH and -NH groups. The optically active pyrrolidine derivatives were obtained from 2-azabicyclo[2.2.1]hept-5-enes, which were synthesized in one step according to the literature procedure by an aza-Diels-Alder reaction between protonated glyoxylate imines possessing two chiral auxiliaries, N-(S)- or N-(R)-1-phenylethyl and (-)-8-phenylmenthyl or (+)-8-phenylneomenthyl, respectively, and cyclopentadiene. These polycyclic aza-Diels-Alder adducts, trough bis-hydroxylation of double bond followed by the oxidative cleavage of the corresponding diols and in situ reduction of the resulting intermediates, afforded 2,3-bis-(hydroxymethyl)-pyrrolidines from which, application of a selective protection/deprotection methodology provided the possibility of regioselective functionalization at positions 1, 2, 3, and 5 of the pyrrolidine scaffold. In conclusion, an efficient and straightforward orthogonal protection/deprotection methodology, allowing selective introduction of functional groups in iminosugars, was developed. References: · Tetrahedron Letters 2006, 47 (43), 7595-7597 · Tetrahedron Letters 1998, 39 (31), 5663-5666 · Tetrahedron 2010, 66 (34), 6797-6805 · Tetrahedron 2011, 67 (37), 7162-7172 · Synthesis 2008, 2008 (EFirst), 971-977 · Tetrahedron Letters 2012, 53 (9), 1029-1032.

Neurodegenerative diseases are one of the major causes of death in aged population all over the world. The Alzheimer\'s disease (AD) is the most common amongst these, followed by the Parkinson\'s disease (PD). The existing therapies (selegiline and rasagiline, propargylaminic drugs usually used in PD treatment as monoamine oxidase-B inhibitors) are still very far from doctor and patient\'s expectations. In this way, the drawing of new therapeutical neuroprotective agents is a great challenge, in order to improve the effectiveness of the existing drugs, or to introduce new alternative therapies. In this work, we describe the synthesis of new propargylic derivatives based on 1-pyrindane ring as a new strategy in the treatment of neurodegenerative diseases. The synthesis was done in due to provide enough number of new compounds endowed with molecular diversity in the pentacyclic ring from 6,7-dihydro-5H-cyclopenta[b]pyridine, commercially available, and 2-bromo-4-methyl-6,7-dihydro-5H-cyclopenta[b]pyridine, easily obtained after bromination of the product of the Sakurai-Midorikawa cyclization between cyclopentanone and ethyl acetoacetate in the presence of ammonium acetate. Classic synthetic methodologies were used, in order to prepare different chemical precursors which will enhance the chemical diversity. In a first step, racemic mixtures was obtained, the enantiomeric pure compounds can be achieved through chemical or enzymatic resolution of the racemates or through enantioselective synthetic processes. In conclusion, a new class of 1-pyrindane derivatives was synthetized, whose synthesis revealed to be effective and simple. After all, the compounds will be evaluated by MAO, AchE and BchE inhibitory activity measure, using selegiline and rasagiline as standards. References · Mechanisms of Ageing and Development 2002, 123 (8), 1081-1086 · Journal of the American Chemical Society 1958, 80 (23), 6254-6257 · Organic & Biomolecular Chemistry 2006, 4 (5), 877-885 · J. Org. Chem. 2004, 69 (15), 5060-5064 · Bulletin of the Chemical Society of Japan 1968, 41 (1), 165-167.

The synthesis of tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methoxy]-1,3,5-triazine and 2-N,4-N,6-N-tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]-1,3,5-triazine-2,4,6-triamine from cyanurate and melamine alkyne derivatives by Huisgen\'s reaction is described

During the last few years our research group has been involved in the investigation of the hydride donor ability of acetalic functions in a series of intramolecular processes. In these reactions the released hydride is transferred to the electrophilic central carbon atom of some heterocumulenic fragments (ketenimines, carbodiimides) and other electrophilic functions. Gratifyingly, we have shown that several of such hydride-like [1,4] and [1,5]-H shifts occur under mild reaction conditions, this migration step being habitually followed by a subsequent pericyclic transformation, most usually a 6π electrocyclic ring-closure (6π-ERC). Following with our efforts in this area we next checked the replacing of the heterocumulenic hydride-accepting function by an allene group, also possessing an electrophilic, sp-hybridized central carbon atom. Surprisingly, when we carried out the thermal activation of a particular class of sulphoxide-substituted acetal-allenes (generated in situ from the respective propargylic sulphoxides) built on an ortho-phenylene scaffold, an unexpected rearrangement, involving the isomeric O-allenyl sulphenate, took place instead of the presumed [1,5]-H/6π-ERC tandem process. In this communication we will disclose the characterization of the reaction products, as well as a mechanistic rationale of the rearrangement.