Barbara Cosimelli

New geiparvarin analogues from 7-(2-oxoethoxy)coumarins as efficient in vitro antitumoral agents

A new class of compounds analogues of geiparvarin is described: aldolic condensation of 3(2H)-furanones and 7-(2-oxoethoxy)coumarins followed by a very efficient dehydration protocol led to the title compounds which show good antitumoral activity against several human cell lines.

Novel N2-substituted pyrazolo[3,4-d]pyrimidine adenosine A3 receptor antagonists: inhibition of A3-mediated human glioblastoma cell proliferation.

Adenosine induces glioma cell proliferation by means of an antiapoptotic effect, which is blocked by cotreatment with selective A(3) AR antagonists. In this study, a novel series of N(2)-substituted pyrazolo[3,4-d]pyrimidines 2a-u was developed as highly potent and selective A(3) AR antagonists. The most performing compounds were derivatives 2a (R(1) = CH(3) and R(2) = COC(6)H(5); K(i) 334, 728, and 0.60 nM at the human A(1), A(2A), and A(3) ARs, respectively) and 2b (R(1) = CH(3) and R(2) = COC(6)H(4)-4-OCH(3); K(i) 1037, 3179, and 0.18 nM at the human A(1), A(2A), and A(3) ARs, respectively), which counteracted the effect of the A(3) AR agonists Cl-IB-MECA and IB-MECA on human glioma U87MG cell proliferation. This effect was concentration-dependent, with IC(50) values comparable to A(3) AR binding affinity values of 2a and 2b, thereby suggesting that their effects were receptor-mediated. Furthermore, the antiproliferative activity of the new compounds was demonstrated to be mediated by the block of A(3) AR agonist activation of intracellular kinases ERK 1/2.

New 5-(2-ethenylsubstituted)-3(2H)-furanones with in vitro antiproliferative activity

Abstract A convenient route to new 3(2H)-furanones is described through hydrogenolysis and subsequent acidic hydrolysis of isoxazoles. The antiproliferative activity of title compounds were evaluated against leukemia-, carcinoma-, neuroblastoma-, and sarcoma-derived human cell lines in comparison to the natural compound geiparvarin. The structure activity relationship indicated that the maximum in vitro antiproliferative activity correlates with the presence of a heterocyclic ring on the ethenyl moiety.

Ring opening of 2-substituted 4-nitrothiophenes with pyrrolidine. Access to new functionalized nitro-unsaturated building blocks

Abstract The reaction conditions of the ring-opening processes of 3-nitrothiophene 7a and of 3-nitrobenzo[b]thiophene 7b with pyrrolidine and silver nitrate were optimized as well as those of the subsequent S-methylation of the ensuing silver enethiolates 8a and 8b to 4-methylthio-2-nitro-1-pyrrolidino-1,3-butadiene 9a and 1-(2-methylthiophenyl)-1-nitro-2-pyrrolidinoethylene 9b. Under such conditions 2-X-substituted 4-nitrothiophenes 7c–i consistently gave good yields of the corresponding 4-methylthio-2-nitro-1-pyrrolidino-4-X-1,3-butadienes 9c–i. The nitroenamine derivatives 9a–i were then reacted with p-tolylmagnesium bromide to furnish moderate to good yields of 4-methylthio-2-nitro-1-(p-tolyl)-4-X-1,3-butadienes 10a,c–i and 1-(2-methylthiophenyl)-1-nitro-2-(p-tolyl)ethylene 10b. Stereochemistry of the interesting building blocks 9a–i and 10a–i was assigned on the grounds of 1H NMR data and NOE experiments.

A new convenient route to 2-oxoethoxycoumarins: key intermediates in the synthesis of natural products

A new synthetic route to coumarinyloxyaldehydes starting from hydroxycoumarins is presented; these compounds, useful intermediates in the preparation of natural products such as geiparvarin and psoralens, are now available in excellent yields with a simple workup procedure. Moreover the reported route has been applied to dihydroxycoumarins.

Novel Irreversible Fluorescent Probes Targeting the 18 kDa Translocator Protein: Synthesis and Biological Characterization

The 18 kDa translocator protein (TSPO) is a mitochondrial protein whose basal density is altered in several diseases, with the result that the evaluation of its expression levels by means of molecular imaging techniques represents a promising diagnostic approach. Experimental procedures using a labeled ligand often cause loss of the bound probe, and consequently high affinity ligands covalently binding the receptor protein are needed to overcome this problem. We have previously described a series of N,N-dialkyl-(2-phenylindol-3-yl)glyoxylamides as potent and selective TSPO ligands. Starting from these derivatives, we designed novel TSPO irreversible ligands bearing an electrophilic isothiocyanato group (7, 8), together with an irreversible NBD-fluorescent probe (18). The TSPO affinity of the new irreversible ligands was measured on rat tissue homogenates by [(3)H]Ro 5-4864 radiobinding kinetic assays, all compounds showing high affinities for the target protein. Further biological characterization of the fluorescent irreversible TSPO probe 18 was carried out by using fluorescent spectroscopy in human glioma cells.

A convenient synthesis of psoralens

An efficient synthesis (yields >70%) of linear 7H-furo[3,2-g]chromen-7-one derivatives (psoralens or furocoumarins) has been carried out starting from ring-substituted 2-(coumarin-7-yl)oxyaldehydes; moreover, the phototoxicity of these compounds has been tested on a cultured cell line of murine fibroblast.

Pyrazolo[1,5-a]pyrido[3,4-e]pyrimidine : a new heterocyclic ring system

Treatment of 6-acetyl-7-(2-dimethylaminovinyl)pyrazolo[1,5a]pyrimidine (1) with hydroxylamine afforded in high yields the pyridine N-oxide (2), a key intermediate in the preparation of new functionalized pyrazolo[1,5-a]pyrido[3,4e]pyrimidine as well as in the synthesis of the parent ring system (8)

A new entry to pyrazolo[1,5-a]pyrido[3,4-e]pyrimidine derivatives

Treatment of 3-aminopyrazoles derivatives with 3-ethoxymethylenpentane-2,4-dione afforded new pyrazol[1,5-a]pyrimidines derivatives which were then converted into enamines by reaction with dimethylformamide dimethyl acetal; ring closure of these latter compounds led to pyrazolo[1,5-a]pyrido[3,4-e]pyrimidines

Allosteric modulators of human A2B adenosine receptor.

BACKGROUND Among adenosine receptors (ARs) the A2B subtype exhibits low affinity for the endogenous agonist compared with the A1, A2A, and A3 subtypes and is therefore activated when concentrations of adenosine increase to a large extent following tissue damages (e.g. ischemia, inflammation). For this reason, A2B AR represents an important pharmacological target. METHODS We evaluated seven 1-benzyl-3-ketoindole derivatives (7-9) for their ability to act as positive or negative allosteric modulators of human A2B AR through binding and functional assays using CHO cells expressing human A1, A2A, A2B, and A3 ARs. RESULTS The investigated compounds behaved as specific positive or negative allosteric modulators of human A2B AR depending on small differences in their structures. The positive allosteric modulators 7a,b and 8a increased agonist efficacy without any effect on agonist potency. The negative allosteric modulators 8b,c and 9a,b reduced agonist potency and efficacy. CONCLUSIONS A number of 1-benzyl-3-ketoindole derivatives were pharmacologically characterized as selective positive (7a,b) or negative (8c, 9a,b) allosteric modulators of human A2B AR. GENERAL SIGNIFICANCE The 1-benzyl-3-ketoindole derivatives 7-9 acting as positive or negative allosteric modulators of human A2B AR represent new pharmacological tools useful for the development of therapeutic agents to treat pathological conditions related to an altered functionality of A2B AR.