S. Hamilakis

A novel synthesis of 3-aryl coumarins and evaluation of their antioxidant and lipoxygenase inhibitory activity.

A series of coumarin analogues bearing a substituted phenyl ring on position 3 were synthesized via a novel methodology, through an intermolecular condensation reaction of 2-hydroxyacetophenones and 2-hydroxybenzaldehyde, with imidazolyl phenylacetic acid active intermediates. The in vitro antioxidant activity of the synthesized compounds was evaluated using two different antioxidant assays (radical scavenging ability of DPPH stable free radical and inhibition of lipid peroxidation induced by the thermal free radical AAPH). Moreover, the ability of the compounds to inhibit soybean lipoxygenase was determined as an indication of potential anti-inflammatory activity.

Structural modifications of coumarin derivatives: Determination of antioxidant and lipoxygenase (LOX) inhibitory activity

In the present project, a series of coumarin analogues, were synthesised and evaluated for their antioxidant and soybean lipoxygenase inhibitory activity. A variety of structural modifications on the coumarin scaffold revealed interesting structure–activity relationships concerning the different biological assays. Prenyloxy-coumarins 9 and 10 displayed the best combined inhibition of lipid peroxidation and soybean lipoxygenase. Thiocoumarins 11 and 14 were identified as potent lipoxygenase inhibitors whereas hydrazone analogues 15 and 16 were efficient DPPH radical scavengers.

An efficient synthesis of 2-amino-3-cyano-2-pyrrolin-4-ones, via the corresponding open chain tautomers (aminoacetylmalononitriles)

Malononitrile has been found to be acylated effectively using N-protected glycines by simultaneous activation of an amino acid carbonyl group and a malononitrile methylene group using carbonyl diimidazole (CDI). The corresponding aminoacetonitriles were isolated as enols and/or as their tautomeric forms, 2-amino-3-cyano-2-pyrrolin-4-ones.

Synthesis, X-ray crystallographic study, and biological evaluation of coumarin and quinolinone carboxamides as anticancer agents

A series of coumarin and quinolinone-3-aminoamide derivatives was synthesized and evaluated for its potency in inhibition of cancer cell growth. The structure of N-[2-(dimethylamino) ethyl]-4-hydroxy-2-oxo-1-phenyl-1,2-dihydroquinoline-3-carboxamide was unambiguously confirmed by X-ray diffraction analysis, which revealed the cis conformation of the amide bond resulting from the presence of two intramolecular hydrogen bonds.Graphical Abstract

Nucleophilic Ring Enlargement of 2-Substituted-3-isothiazolones to 1,3-Thiazin-4-ones

Abstract 1,3-Thiazin-4-ones 9 and 10 have been prepared from the corresponding isothiazolones 7 and 8 by a clean and smooth reaction with tertiary amines at room temperature. This rearrangement is attributed to the abstraction of a methine proton from the 2-position isothiazolone substituent, followed by ring enlargement through cleavage of the S-N bond.

CdSe semiconducting layers produced by pulse electrolysis

Thin films of CdSe semiconductors electro deposited from acid aqueous electrolytes onto Ti substrates have been developed using periodically modified currents, such as pulse current. The products obtained were fully characterized and their photoelectric behavior was studied using a photo electro chemical cell. All deposits obtained by pulse electrolysis exhibit some differences in their structure, surface morphology and photoelectric properties, depending on the imposed pulse current parameters such as pulse frequency and duty cycle. It was also found that increased photoelectrochemical efficiencies are observed to so higher pulse frequencies as more negative deposition potentials are applied and vice-versa.

Low-Cost Synthesis of Fullerene Derivatives

Abstract Refined mixed fullerenes were used as a reagent in known organic reactions instead of the pure fullerene C60 with aim to find an alternative, low-cost method for the synthesis of fullerene derivatives potentially exhibiting photoconductive properties. The isolation of C60 or C70 in clean form without admixtures requires the use of large quantities of toluene or other nonpolar solvents, polluting the environment and multiplying the production cost. 1,3-Dipolar cycloaddition of azomethine ylide to fullerite was chosen because this reaction is one of the most widely used for fullerene functionalization, producing material possibly presenting photoinducing behavior. The data showed that the use of the cheaper mixed fullerenes instead of pure C60 leads to the isolation of the same expected products with similar yields. The photoelectric properties of mixed fullerenes and their organic derivatives were also examined. A slightly semiconductive behavior was confirmed as well as a noticeable photoresponse. Supplemental materials are available for this article. Go to the publishers online edition of Synthetic Communications® to view the free supplemental file. GRAPHICAL ABSTRACT

Development of new CdTe based hybrid semiconducting layers produced in one step by electro-codeposition

Thin layers of new hybrid organic-inorganic semiconductors, exhibiting photoconductive properties have been produced by a new, one step method. The films result by the combination of a CdTe semiconductor with an appropriate slightly water soluble fullerene salt. The layers were prepared using a cathodic electro-codeposition technique from an electrolytic bath containing both the convenient inorganic and organic chemical species. Using XRD and SEM-EDAX techniques the development of a new hybrid semiconductive system was confirmed. The photoconductive behavior of the new materials obtained was confirmed by photoelectrochemical measurements. The electro-codeposition technique applied could permit the achievement of various new hybrid materials with interesting semiconducting behavior, selecting either the appropriate inorganic and organic reagents or the imposed electrolysis conditions.

One Pot Synthesis of Methyl Aminoacetylcyanoacetates

Abstract The C-acylation reactions of the methyl cyanoacetate with N-protected glycines by simultaneous activation of the amino acid carbonyl group and the methyl cyanoacetate methylene group using carbonyl diimidazole (CDI) have been here performed. The corresponding aminoacetylcyanoacetates were isolated (devoided of any impurities) as enols 4 in high yields, with a simple experimental, one pot, procedure.

Production and identification of highly photoconductive CdSe-based hybrid organic-inorganic multi-layer materials

Highly photoconductive thin multi-layers of new hybrid organic-inorganic semiconductors have been developed. They result by the combination of an inorganic semiconductor with ferrocene, a commercially available compound, applying the electrodeposition and spin coating techniques, introducing sodium oxalate as an additive in the electrolytic bath. The organic layer of the hybrid system is enveloped between two inorganic layers in a sandwich-like structure. The full characterization of the final products by XRD, SEM-EDAX, band gap and photo electro chemical cell (PEC) measurements confirmed the development of the hybrid semiconducting system. The outer electrodeposited CdSe layer of the sandwich-like materials exhibits a definite hexagonal structure, whereas, as derived from the XRD and band gap data, the development of a new semiconducting compound has been confirmed. Thus, due to a synergic action, the three-layer materials present a remarkably improved photoresponse compared to that of the pure cubic CdSe electrodeposited in the presence of the oxalate additive as well as the three-layer hybrid CdSe-based products developed in our previous work in additive-free electrolytic baths.