Silvia Capacchi

Synthesis, structural characterization and biological activity of helicin thiosemicarbazone monohydrate and a copper(II) complex of salicylaldehyde thiosemicarbazone

Abstract Two new compounds, helicin (i.e. salicylaldehyde-β- d -glycoside) thiosemicarbazone monohydrate, Het·H2O (1), and bis[aqua(salicylaldehyde thiosemicarbazonato)copper(II)]sulfate bisdimethylsulfoxide solvate hexahydrate [Cu(Hsalt)(OH2)]2SO4 · 2DMSO · 6H2O (2) (H2salt=salicylaldehyde thiosemicarbazone) were synthesized and characterized by means of NMR, IR and X-ray techniques. Molecule 1 consists of three units: the sugar, the benzene ring and the thiosemicarbazonic chain. In the reaction of 1 with CuSO4 the helicin thiosemicarbazone was hydrolyzed giving rise to the salicylaldehyde thiosemicarbazone, so forming complex 2. The molecular structure of 2 consists of centrosymmetric dimeric cations, sulfate anions lying on a crystallographic two-fold axis, DMSO and water solvate molecules. The dimeric cations are due to a long Cu–aromatic ring interaction. Moreover, for both compounds assays of proliferation inhibition and apoptosis tests in vitro on human leukemic cell lines U937 were carried out.

Synthesis, spectroscopic characterization and biological properties of new natural aldehydes thiosemicarbazones

As part of a research programme aimed at the synthesis of compounds with antiviral, antibacterial and antitumor properties and their spectroscopic characterization, new thiosemicarbazones deriving from natural aldehydes have been investigated. These substances contain in the same molecule both a chain with nucleophilic centres N, S with tubercolostatic activity, and a glycosidic or alkyl moiety (modified glycosides and nucleosides have recently received a great deal of attention in the fields of neoplastic diseases and viral infections). In this paper the synthesis and the characterization of these compounds by means of 1H NMR, IR, and MS techniques is reported. Biological studies have involved both inhibition of cell proliferation and apoptosis tests on human leukemia cell line U937.

Synthesis, characterization and X-ray structures of new antiproliferative and proapoptotic natural aldehyde thiosemicarbazones and their nickel(II) and copper(II) complexes

Synthesis and characterization of new thiosemicarbazones derived from natural aldehydes (1-9) have been investigated in order to develop a research program aimed at the development of compounds with antiviral, antibacterial, and antitumor properties. These substances contain both a chain with N and S nucleophilic centers with tuberculostatic activity, and an alkyl or terpenic moiety. In addition, a few nickel(II) and copper(II) complexes (10-18), derived also from the previously studied ligands, were synthesized and characterized by means of NMR and IR techniques. The trans-2-octenal N(1)-phenylthiosemicarbazone and its nickel complex were also characterized by X-ray diffractometry. Biological studies, performed with some of these compounds, have involved both inhibition of cell proliferation and apoptosis tests in vitro on human leukemia cell line U937 to deepen our knowledge on the way these substances interfere with biological processes in leukemic cells.

Synthesis, structural characterization and biological activity of p-fluorobenzaldehyde thiosemicarbazones and of a nickel complex.

New thiosemicarbazones (1-7), derived from p-fluorobenzaldehyde and differently substituted thiosemicarbazides, were synthetized and characterized by means of NMR and IR techniques. The p-fluorobenzaldehyde thiosemicarbazone Hfbt (1), the p-fluorobenzaldehyde 4-phenylthiosemicarbazone Ph-Hfbt (4) and complex [Ni(fbt)2] (8) were also characterized by X-ray diffractometry. Molecules 1 and 4 consist of two units: the p-fluorobenzaldehyde residue and the thiosemicarbazonic chain. In the reaction of 1 with NiAc2.4H2O, complex 8 was afforded. The molecular structure of 8 consists of the neutral molecules [Ni(fbt)2] with the metal placed on a symmetry centre. The coordination results in a square planar configuration and involves the sulphur atom and the hydrazine nitrogen atom of the two ligands in a trans configuration. Moreover, for compounds 1, 2, 4, and 8, assays of proliferation inhibition and apoptosis tests in vitro on human leukemia cell line U937 were carried out.

Synthesis and characterization of square planar nickel(II) complexes with p-fluorobenzaldehyde thiosemicarbazone derivatives

Abstract New thiosemicarbazone nickel complexes (1–7), derived from p-fluorobenzaldehyde and differently substituted thiosemicarbazides, were synthetized and characterized by means of NMR and IR techniques. The p-fluorobenzaldehyde 4-ethylthiosemicarbazone Et-Hfbt (1) and its complex [Ni(Et-fbt)2] (2) were also characterized by X-ray diffractometry. Molecule 1 consists of two units: the p-fluorobenzaldehyde residue and the thiosemicarbazonic chain. In the reaction of 1 with NiAc2·4H2O, complex 2 was afforded. The molecular structure of 2 consists of the neutral complexes [Ni(Et-fbt)2] with the metal not lying on a symmetry centre, with two consequently independent ligand molecules; the coordination results in a square planar geometry slightly twisted towards a tetrahedron, involving the sulfur and the hydrazine nitrogen atoms of the two ligands in a trans configuration.

SYNTHESIS, CHARACTERISATION AND CONFORMATIONAL STUDIES OF LIPOPHILIC, AMPHIPHILIC AND WATER-SOLUBLE C-GLYCO-CONJUGATED PORPHYRINS

Abstract Synthesis, stereodisposition and nonplanar macrocyclic distortions of the four compounds 1–4 obtained from pyrrole, BF3·OEt2 and isopropylidene-protected d -glyceraldehyde, were investigated. Experiments of selective deprotection of these lipophilic compounds, depending both on the starting porphyrins stereodisposition and on the deprotecting agent (TFA) concentration, were carried out on such macrocycles, bearing easily removable protecting groups, to obtain water-soluble (5 and 8) and amphiphilic (6 and 7) porphyrins. Reactions of these macrocycles with Zn(II)-, Pd(II)-, Rh(II)-, Pb(II)-, Cu(II)- and Ni(II)-acetate, and the subsequent deprotection of compounds 9 and 13 affording the corresponding water-soluble C-glyco-porphyrinates (17 and 18) were studied. In the absence of crystals for X-ray studies, computational simulations were carried out to analyse the structural behaviour of some of these compounds.

Acyclic C-nucleosides: synthesis of chiral 1,1-diheteroaryl-alditols and X-ray crystal structure of 2,3,5-tri-O-benzyl-1,1-di-(2′-pyrryl)-1-deoxy-d-arabinitol

Abstract Tetra- O -acetyl- d -ribose, penta- O -acetyl- d -glucose, 2,3;5,6-di- O -isopropylidene- d -mannofuranose, 2,3,5-tri- O -benzyl- d -arabinofuranose and 2,3,5,6-tetra- O -benzyl- d -glucose react with pyrrole and indole, in presence of Lewis acids, to afford C-glycosylpyrroles and indoles in position 2 and 3 respectively (acyclic C-nucleosides, 1–7 ). The crystal structure of 4 was determined by X-ray crystallography.

Synthesis and functionalization of chiral superstructured porphyrins

Abstract Chiral porphyrins 1 and 2, bearing, respectively, four and two chains at the meso carbons, each one with a stereocentre at C-2 and a double bond at C-5, were functionalized to afford the corresponding thiosemicarbazonic derivatives 9–12 and the nickel(II) porphyrinato 13, compounds with potential antiviral, antibacterial and antitumour properties. To verify the biological activity of some of these products, assays of proliferation inhibition and apoptosis tests in vitro on human leukemic cell lines U937 were carried out for compounds 1, 6, 9 and 10.

Short synthesis of chiral tentacled porphyrins using pyrrolylmagnesiumbromide and (3R)-(+)-citronellal

Abstract The reaction between pyrrolylmagnesiumbromide and (3 R )-(+)-citronellal produced porphyrin 1 with four chains at the meso carbons, each one bearing a stereogenic centre at C-2 and a double bond at C-5. 4′-Fluoro-phenyldipyrrylmethanebismagnesiumbromide 4 with (3 R )-(+)-citronellal gave rise to porphyrin 2 with two stereogenic chains.

Database of C-glycosylporphyrins in Web fashion.

The aim of this work was to organize chemical data in a client-server environment using Database Management System and Web fashion for the client interface. To solve this ancient problem (for us) merging text data, reaction schemes, tridimensional structures, and NMR, CD, and UV spectra images, we have based our implementation on a few fundamental points: no cost for the user, availability of data via the Internet, standard and freeware software, and a Web browser for the database inquiry. These functions are delivered in a platform-independent manner via the Internet and are used by computational experts and nonexperts alike. C-Glycosylporphyrins is the class of compounds chosen to test our applications. These results can be exportable for many other classes of chemical compounds.