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A series of 3- and 5-methylthiophene-2-carboxaldehyde α-(N)-heterocyclichydrazones were synthesized and submitted to an in vitro investigation of their anticancer, anti-HIV and antimicrobial activities. Some of the newly synthesized compounds were found to possess antiproliferative properties, whereas no anti-HIV activity was seen; the most active of the series was the derivative 2i, which exhibited tumour growth inhibition activity against all cell lines displaying GI50 values between 1.63 and 26.5 μM. The title compounds were generally ineffective against Gram-positive and Gram-negative bacteria, while showed a moderate antifungal activity against C. albicans and A. fumigatus. [Copyright &y& Elsevier]

Novel 2-phenyl-2,5-dihydropyrazolo[4,3-c]quinolin-3-(3H)-ones (PQs) endowed with high affinity for central benzodiazepine receptor (BzR) were synthesized. In particular, 9-fluoro-2-(2-fluorophenyl)-2,5-dihydro-3H-pyrazolo[4,3-c]quinolin-3-one (22) showed binding affinity in the subnanomolar concentration range and proved to be in vitro a potent antagonist. This finding allowed the nature of the hydrogen bonding receptor site H2 to be established, as located between the N-1 nitrogen of the PQ nucleus and the ortho position of the N-2-aryl group. [35S]tert-Butylbicyclophosphorothionate ([35S]TBPS) binding assays and electrophysiological measurements of the effects on GABA-evoked Cl− currents at recombinant human α1β2γ2L GABAA receptors, expressed in Xenopus laevis oocytes, were used to assess the intrinsic activities of a large series of PQs. With the aim of extracting discriminant information and distinguishing BzR ligands with different profiles of efficacy, 51 PQ derivatives, including full and partial agonists, antagonists, and inverse agonists, were analyzed in a multidimensional chemical descriptor space, defined by the lipophilicity parameter CLOG P and 3-D molecular WHIM descriptors, by means of principal component analysis, k-nearest neighbors (k-NN) method, and linear discriminant analysis (LDA). The classification methods were applied to subsets of pairs of efficacy classes, and lipophilicity and 3-D size descriptors were detected as the discriminant variables by a stepwise linear discriminant analysis. LDA proved to be superior to k-NN, especially in classifying PQ ligands (60–84% of success in prediction ability) into categories of efficacies which were contiguous and quite overlapped in the hyperspace of variables. [Copyright &y& Elsevier]

A series of 4-quinolylhydrazones were synthesized and tested against Mycobacterium tuberculosis H37Rv. Preparation of the title compounds was achieved by reaction of 4-quinolylhydrazine and aryl- or heteroaryl-carboxaldehyde. For the most of derivatives interesting antitubercular properties were showed; two compounds (32 and 325), identified as the most active, were tested also against Mycobacterium avium. [Copyright &y& Elsevier]