Dipolar chromophores of the type, donor – π-bridge – acceptor, are currently of great interest due to their applicability in optical and photovoltaic devices such as nonlinear optics (NLO) and dye-sensitized solar cells (DSCCs). Recently, there has been a wide range of structural modifications to the donor and acceptor groups as well as in the π-bridge of organic chromophores, in order to improve their NLO properties and DSCCs performance.¹Conjugated (hetero)aryl-pyridazines, functionalized with the formyl-group on the aryl or on the heteroaryl moiety, could be used as versatile precursors in the preparation of functional π-conjugated heterocyclic systems with several optoelectronic applications (e.g., NLO, DSSC).Having in mind these facts and as part of an on-going research to develop efficient donor-acceptor substituted heterocyclic systems for several optical applications² we synthesized thienyl-pyridazines 3-4 through Suzuki coupling of bromo-thienylpyridazine 2 with commercially available (hetero)aryl-boronic acids. On the other hand, precursor 2 was prepared by reaction of thienylpyridazinone 1 with POBr₃.³In this communication we report on the synthesis and characterization of the novel formyl-thienyl-pyridazine derivatives 3-4. In the future, these heterocyclic systems will be further functionalized and characterized in order to evaluate their potential application in NLO or as dyes sensitizers for DSCCs.

Selectively N-substituted 1,4-diaminobutane (putrescine) and 1,5-diaminopentane (cadaverine) derivatives are of biochemical and pharmacological interest as synthetic analogs of natural polyamines. Several derivatives have been described acting as antibiotics, antineoplastics, antiparasitic agents, and NMDA or cholinergic modulators. In addition, such compounds represent key intermediates for acyclic and heterocyclic polyamine derivatives.N-Aryl putrescines and cadaverines represent a challenge, since the available methods for di and trimethylenediamines are not generally suitable for their higher homologs. The literature regarding N-alkyl-N-arylputrescines and cadaverines is even scarcer.N-Alkylation is conceptually the most straightforward disconnection towards tertiary amines. Although this transformation seems rather simple, the fact that the newly formed amines are also nucleophilic brings about bis and/or polyalkylation byproducts. Therefore, improvement in the selectivity of the reaction would increase the chemical yields and lead to easier purification protocols.In this work we present a practical method for the synthesis of tertiary N-aryltetra and pentamethylenediamines, by selective monoalkylation of N-alkylanilines followed by reduction. The optimized reaction conditions resulted in a simplified procedure, remarkable selectivity in the alkylation step and high global yields of the diamines. We examined in the first place the synthesis of N-methyl-N-phenylputrescine using different reaction conditions (solvent, base, molar ratios) for the N-alkylation step. The best results were obtained using K₂CO₃ as the base, DMF as the solvent and a molar ratio 2:1 between arylamine and halonitrile. In such conditions, selectivity toward the N-alkylation product was complete, allowing for the direct reduction of the crude aminolysis product.    Employing the optimized experimental conditions, a series of N-aryl-N-alkyl cadaverines and putrescines were prepared in high overall yields (64-87%). The sequence employs readily available and inexpensive starting materials, involves two steps and one column purification and represents an advantageous alternative to other synthetic approaches.

In this study a series of twelve ring-substituted 8-hydroxyquinoline-2-carboxanilides was prepared and characterized. The discussed compounds were synthesized by using microwave-assisted synthesis. The compounds were tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. The compounds were found to inhibit PET in photosystem II. Significant PET-inhibiting activity was observed for meta-substituted compounds showing IC₅₀ values close to that of photosystem II herbicide DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea, IC₅₀ = 1.9 μmol/L). N-(3-Fluorophenyl)-8-hydroxyquinoline-2-carboxamide showed the highest PET inhibition. The activity of meta- and para-substituted compounds decreased with lipophilicity increase and electron-withdrawing effect. No influence of any of these parameters on PET-inhibiting activity of ortho-substituted compounds was observed.

The G-1 dendrimer 4,4',4'',4'''-methanetetrayltetrakis(N-(3,5-dicarboxy-phenyl)benzamide) has been obtained from 4,4',4'',4'''-methanetetrayltetrabenzoic acid and isophtalic acid. The compound was recrystallized from methanol and its structure resolved. The crystal belongs to the tetragonal crystal system space group I-4 2d, the cell lengths being a=18.9585(16) Å, b= 18.9585(16) Å and c=23.703(2) Å. The crystal structure evidences the formation of cavities. Only one type of hydrogen bond is observed implying the nitrogen atom (acting as donor) and the oxygen atom of one carboxy group of the aminoisophtalic residue (as acceptor), while the other carboxy group does not participate in the network. The donor-acceptor distance is 3.024(2) Å.

Cyanothioacetamide reacts with pyrazole-3(5)-diazonium chlorides under mild conditions to afford pyrazolo[5,1-c][1,2,4]triazine-3-carbothioamides. The latter can be oxidized with H2O2 to give either pyrazolo[5,1-c][1,2,4]triazine-3-carboxamides or 1,2,4-thiadiazole derivatives, depending on the reaction conditions. The Hantzsch-type reaction of thioamides 5 with α-bromo ketones leads to 3-(thiazol-2-yl)pyrazolo[5,1-c][1,2,4]triazines.

Thiosemicarbazones, were obtained by condensation of thiosemicarbazide with suitablealdehydes or ketones, act as ligand in the preparation of their complexes. They bind to themetal through N and S atoms. Their metal complexes may have biological properties. In thiswork, di chloro 4-pyridinecarboxaldehyde thiosemicarbazone cadmium (II) was synthesizedby an efficient and facile microwave heating technique. The reaction was performed usingCdCl2.H2O as metal source and 4-pyridinecarboxaldehyde thiosemicarbazone as ligand in 1:1molar ratio in EtOH under microwave irradiation with the power of 100 W for 30 sec. Theprogress of the reaction was monitored by TLC. The product was characterized by Fouriertransform infrared (FT-IR), 1H-, 13C- NMR spectroscopy and elemental analysis. Spectroscopic data:IR (KBr, cm-1): 3440(m), 3317(m), 3172(m), 1541(s), 1326(s), 823(m), 655(m), 530(m).1HNMR (DMSO-d6, ppm) δH: 7.78(s, 2H), 8.21(s, 2H), 8.39(s, 1H), 8.57 (d, 2H), 11.69(s,1H).13CNMR (DMSO-d6, ppm) δC: 121.88, 139.93, 142.66, 150.30, 178.68. Elemental analysis:Anal. Calc. for C7H8N4SCdCl2: C, 23.14; H, 2.20; N, 15.42. Found C, 24.29; H, 2.18; N,15.27.

Organotin compounds have shown a wide spectrum of biological effects and have been extensively studied as fungicides, bactericides, acaricides and wood preservative. A large number of papers have reported the use of organotin compounds as bacterial growth inhibitors. The biocide activity of tribenzyl- and dibenzyltin compounds has been informed, but the effect that the methoxyl group in the aromatic ring could have on the activity of the compounds has not been reported in previous literature. For that reason, we performed an in vitro qualitative assay, and evaluated the activity of benzyltri-n-butyltin (I) and 3,5-dimethoxybenzyltri-n-butyltin (II) against the growth of two bacterial strains: Staphylococcus aureus (Gram-positive) and Escherichia Coli (Gram-negative), using agar well diffusion method. In all cases Merck Art 5273 broth was employed. THF was used both as the solvent of choice for the organometallic compound (since the organotin compounds are not water soluble) and as a negative control. Different concentrations I and II were prepared and the activity was determined by measuring the diameter of the inhibition zone (in cm). The results proved not only that the Gram-positive strain is more susceptible to the inhibition growth effect of the organotin compounds evaluated, but also that 3,5-dimethoxybenzyltri-n-butyltin has higher antibacterial activity. According to this preliminary results we conclude that the presence of the methoxyl group in the aromatic ring would enhance the antibacterial activity of the organotin compound tested here.

Due to wide synthetic utility of α-phenylseleno carbonyl compounds, and α-sulfenyl ketones, much effort has been devoted to accomplish the synthesis of these compounds. For example, α-phenylseleno aldehydes and ketones can be converted into the corresponding synthetically useful α,β-unsaturated carbonyl compounds through selenoxide elimination reactions. In addition, these compounds can be transformed into other important organic intermediates such as amines, α-amino acids, allylic alcohols, aziridines, and α-hydroxy esters. Several procedures have been developed for the preparation of α-phenylseleno aldehydes and ketones, including: reaction of electrophilic organoselenium reagents with aldehydes, ketone enolates or enolate derivatives, nucleophilic reaction of phenylselenolates with α-halo aldehydes or ketones, and insertion of elemental selenium into zinc carbon bond. Herein, we have developed a new convenient and efficient protocol for α-arylchalcogenation of aldehydes and ketones with diaryl dichalcogenides in the presence of K3PO4 under mild reaction conditions with good to high yields. This process represents a suitable option to existing methods.

In the present work synthesis routes and the reactions involved in the polymerization of two organic compounds similar to natural rubber were studied. To these routes and reactions, modifications related with the previously reported in the literature were performed in order to study them through theoretical tools and determine their prediction capability for the design of those analogs. The semiempirical method Austin Model 1 (AM1) was used for the study of electronic configurations and it was shown that the synthesis of the polystyrene polymer (PS) and the poly copolymer (styrene-butadiene) (SBR) is possible through the use of free radicals from styrene and 1,3-butadiene monomers using benzoyl peroxide as the catalyst in both cases; going through the intermediates 1-phenyl-2-[(phenylcarbonyl)oxy]ethyl and (2E)-4(oxy (phenylcarbonyl))2-buten-1-yl. The results show that the higher electronic densities are found over the active atom in the radical compared to the electronic densities over the ions and the interest atoms in a possible condensation. Additionally, the study of the reaction mechanisms for the designed organic synthesis routes was performed by applying the frontier orbitals theory developed by R. B. Woodward, and R. Hoffmann and the respective correlation diagrams that showed thermal viability were built demonstrating the consistency between the characteristics of the orbital symmetry in the concerted reactions of the reactants and products; therefore it is seen that the free radical synthesis do not show symmetry restrictions, and it is possible to make it by a thermal route with low activation energy thresholds. The experimental yields of polymerizations were 90% and 75% for polystyrene (PS) and poly (styrene-butadiene) (SBR) respectively. Additionally mechanical tests were performed to the synthesized polymers and it was proved that the properties of the synthesized compounds are consistent with those reported in the literature. In the future it is expected to explore unknown organic synthetic routes with this research it was demonstrated that the methods are reliable.

The "ab initio" (MP2) level of theory using 6-311+G(d,p) basis set has been carried out to explore the isomeric structures, energies, and properties of substitued (-H, -CH3, -SiH3, -OH) LiBr-silacyclopropylidenoids. The resulting isomeric structures of LiBr-silacyclopropylidenes reveal three stationary structures: silylenoidal (S), inverted (I), and tetrahedral (T). The theoretical calculations indicate that all substituted LiBr-silacyclopropylidenoids have silylenoidal (S), inverted (I), and tetrahedral (T) forms except –OH substituted silylenoid. Interestingly we have obtained no tetrahedral structure as a minimum for the –OH substituted structure. The silylenoidal forms energetically more stable than the inverted (I) and tetrahedral (T) forms, whereas stability of the tetrahedral (T) forms for the title structures lower than the inverted (I) and silylenoidal (S) forms.