Giovanni Grassi

A convenient synthesis of furo[3,2-c]coumarins by a tandem alkylation/intramolecular aldolisation reaction

Abstract A simple and efficient synthesis of furo[3,2- c ]coumarin derivatives from 4-hydroxycoumarin and α-haloketones via a tandem O -alkylation/cyclisation protocol is described.

First synthesis of a bromonitrilimine. Direct formation of 3-bromopyrazole derivatives

The first example of the preparation of bromonitrilimine 3 is described. This precursor provides a convenient entry to highly regioselective synthesis of 3-bromopyrazole derivatives 4 and 5.

Recent Advances in Carbon Nanotubes as Delivery Systems for Anticancer Drugs

Problems associated with the administration of anticancer drugs, such as limited solubility, poor biodistribution,lack of selectivity, and healthy tissue damage, can be overcome by the implementation of drug delivery systems. A wide range of materials, including liposomes, microspheres, polymers and recently, carbon nanotubes (CNTs), have been investigated for delivering anticancer drugs on the purpose of reducing the number of necessary administrations, providing more localized and better use of the active agents, and increasing patient compliance. Carbon nanotubes (CNTs) have attracted particular attention as carriers of biologically relevant molecules due to their unique physical, chemical and physiological properties. The exact relationship between the physical-chemical properties of carbon nanotubes, their cell to-cell interactions, reactivity, and biological/systemic consequences are relevant issues and it is important to know suchinter-relationships beforehand to employ the benefits of these nanomaterials without the hazardous consequences. The purpose of this review is to present highlight of recent developments in the application of carbon nanotubes as cargoes for anti cancer drugs and in the diagnosis of cancer diseases.

Stereoselective synthesis of homochiral annulated sultams via intramolecular cycloaddition reactions

Abstract Different homochiral dipoles containing a sulfonamido group have been synthesized, starting from l -amino acids, and used for the construction of functionalized and enantiomerically pure annulated sultams.

Diastereoselective Synthesis ofN,O-Psiconucleosides, a New Class of Modified Nucleosides

Anomeric α- and β-N,O-psiconucleosides were prepared by 1,3-dipolar cycloaddition of C-ethoxycarbonyl N-methyl nitrone with ethyl 2-acetyloxyacrylate, followed by Vorbruggen nucleosidation. The synthetic scheme has been applied to all purine and pyrimidine nucleobases. Nucleosidation can proceed under kinetic and under thermodynamic control; under thermodynamic control conditions only β-nucleosides are obtained for pyrimidine derivatives and α-nucleosides for purine derivatives. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Diastereoselective multicomponent synthesis and anti-HSV-1 evaluation of dihydrofuran-fused derivatives

Enolizable 6-membered cyclic 1,3-dicarbonyls undergo an efficient and diastereoselective domino condensation/addition/heterocyclization reaction with arylaldehydes and phenacyl chloride, producing highly substituted dihydrofuran-fused derivatives. Ring size of the cyclic 1,3-dicarbonyls and the presence of at least one keto group are crucial to the reaction’s success. The new compounds were evaluated in vitro for antiviral activity against herpes simplex virus type-1 (HSV-1). Interestingly, some of them appeared able to interfere with HSV-1 replication, without detection of cytotoxic effects.

Synthesis and anti HSV-1 evaluation of novel indole-3,4-diones

A novel class of water soluble indole-3,4-diones has been synthesized and evaluated in vitro for antiviral activity against HSV-1. The results showed lack of cytotoxicity and significant antiviral activity. The cellular internalization efficiency and the antiherpetic effect were successfully increased by incorporation into nanoaggregates of an amphiphilic β-cyclodextrin.

β-Cyclodextrin-grafted on multiwalled carbon nanotubes as versatile nanoplatform for entrapment of guanine-based drugs

The design of β-cyclodextrin/multiwalled carbon nanotubes hybrid (β-CD-MWCNT) as nanoplatform for the entrapment and delivery of guanine based drugs is described here. The functionalized carbon nanomaterials have been characterized by XPS spectroscopy, electron microscopy (FEG-SEM and TEM), AFM, TGA, and FT-IR to achieve insights on structure, morphology and chemical composition. The drug binding abilities of nanocarrier towards the guanine (G) and Acyclovir (Acy) were proved by UV-vis and DSC experiments. Host-guest equilibrium association constants and drug loading have been evaluated for G/β-CD-MWCNT and Acy/β-CD-MWCNT complexes. The release studies showed a sustained delivery of Acy without initial burst effect confirming a strong interaction of drug with the nanoplatform sites. The preliminary antiviral data indicated that the Acyclovir loaded into the β-CD-MWCNT platform interferes with HSV-1 replication and the antireplicative effect was higher than the free drug.

Direct synthesis of C3-mono-functionalized oxindoles from N-unprotected 2-oxindole and their antileishmanial activity.

A novel approach for the synthesis of unprecedented C3-mono-functionalized indolin-2-ones is reported, starting from 2-oxindole and chalcones. The reactions proceed regioselectively under mild conditions, without di- and tri-alkylated side products. The new compounds have been evaluated in vitro for their antiproliferative effects against the protozoan Leishmania infantum. Interestingly, they appear able to kill L. infantum promastigotes and amastigotes, without significant cytotoxic effects.

Synthesis of Stannyl Porphyrins and Porphyrin Dimers via Stille Coupling and Their 119Sn NMR and Fluorescence Properties

Free base stannyl porphyrins and free base porphyrin dimers have been successfully synthesized via copper-free Stille coupling in 21-67% yields. This approach provides an access to stannyl porphyrin synthons that were previously unavailable. Moreover, variation of the reaction conditions selectively provides access to either stannyl porphyrins or porphyrin dimers. Full (119/117)Sn NMR analysis was used for characterization of the stannyl porphyrins and detailed (119)Sn-(1)H-(13)C NMR analyses were carried out on a series of the starting tin reagents and the stannyl porphyrins. These investigations indicate that significant structural information can be gathered by use of commonly known NMR techniques. Photophysical properties of the novel porphyrins prepared including absorption, emission, and fluorescence lifetimes were investigated. The stannyl porphyrins emitted in the visible region, and in all cases large Stokes shifts were observed. The emission intensities of the stannyl porphyrins were 100-fold higher than those of the starting bromoporphyrins. Measured fluorescence lifetime (S(0)-->S(1)) of the stannyl and dimeric porphyrins were in the 7.7-12 ns region.