Letters in Drug Design & Discovery - Volume 7, Issue 6, 2010

3-N-alkyloxyestradiol derivatives were synthesized, characterized and tested for activity in MCF-7 human breast cancer cells. Among the compounds, the diisopropyl and piperidinyl derivatives were found to be more active than 4-hydroxytamoxifen (HO-Tam), the active metabolite of tamoxifen based upon IC50 values. The IC50s were correlated with structures using molecular modeling.

A 3D-QSAR study has been performed using Self-organizing molecular field analysis (SOMFA) on a novel class of pyridazine analogues as non-competitive and reversible inhibitors of PTP 1B. SOMFA is a novel 3D-QSAR methodology, similar to both comparative molecular field analysis (CoMFA) and molecular similarity studies. SOMFA studies have been performed to correlate chemical structures of pyridazine analogues with their observed PTP 1B inhibitory activity. The master grid obtained for the various SOMFA models indicates electrostatic and shape potential contributions. These can be mapped back onto the structural features relating to trends in activities of the molecules. On the basis of the spatial arrangement of the various shape and electrostatic potential contributions, new inhibitors of PTP 1B can be designed with improved spectrum of activity for the management of type 2 diabetes.

A novel series of 7-(hetero)aryl substituted-pyrazolopyrimidines, prepared via an AlCl3 induced C-C bond forming reaction of 7-chloro-5-phenyl-pyrazolo[1,5-a]pyrimidine with arenes and heteroarenes have been investigated as PDE4 inhibitors. Among all the compounds tested the 7-indolyl substituted pyrazolopyrimidine showed good inhibition of PDE 4 in vitro.

Drug-induced long QT syndrome (LQTS) that may lead to sudden cardiac death has become one of the key reasons for which some drugs fail to enter market, while others have been withdrawn from the market. Early identification of chemical entities causing LQTS is of extreme importance relevant to the production of safer drugs as well as to the direct reduction of attrition rate in drug development. In the present study, we have employed fourteen classification methods to develop a prediction model for cardio-toxicity. The analyses have been carried out on 127 drugs inducing LQTS and 250 cardio-safe drugs. These compounds have been randomly divided into two sets, namely a training set (consisting of 2/3) and a test set (consisting of 1/3). CONCLUSIONS: When models from different algorithms are combined using the proposed method, quality compared to the individual models is consistently and significantly improved in both training and test sets. The accuracy of our approach has 10-25% improvement over the best result obtained by individual classification techniques. The proposed strategy could be employed to infer cardio-toxicity or -safety for current and potential drugs. Certainly, it will also have important impact on decision making in the fields of screening molecules for drug development, biological activity, and other applications as well.

In order to complete the SAR and discover new potent and selective PCOs, some changes were made to the C-4 and C-2 substitutions of cromakalim. A series of 4 -amino acid substituted -2, 2-dialkylchromans structurally related to cromakalim were synthesized and evaluated, as ATP-sensitive potassium channel openers (8a-l). Preliminary biological tests suggested that these compounds exhibited potent to mild relaxation activity of the KCl-contracted rat aortic strips. Compounds 8b (IC50 =0.25μM), 8f (IC50 =6.44μM) and 8j (IC50 =8.65μM) exhibited commendable opening activity of potassium channels. In addition to anti-hypertension, these compounds can also be considered as lead candidates for the further development of myocardial antiischemic drugs.

1,3-dioxane carboxylic acid derivatives were prepared based on our previous studies directed towards identifying novel pharmacophore for the development of PPAR α/γ dual agonists. Based on the typical topology of PPAR agonists we focused our design approach on modifying lipophilic tail and prepared a series of compounds by replacing the oxazole moiety of our previously reported compound with optimized lipophilic groups. Compound 8a was found to be a weak PPAR activator but exhibited potent hypolipidemic and anti-hyperglycemic activities in vivo due to superior bioavailability, whereas 8f exhibited potent in vitro and invivo effects. The activity of 8f is further supported by molecular docking study.

Twelve pyrrole hydrazones were synthesized and evaluated in vitro as inhibitors of Mycobacterium tuberculosis H37Rv with IC50 and IC90 to 5.92 μg/ml and 9.37 μg/ml respectively. The most active 12d (ethyl 5-(4-chlorophenyl)- 2-methyl-1-(4-(2-((5-nitrofuran-2-yl)methylene)hydrazinyl)-4-oxobutyl)-1H-pyrrole-3-carboxylate) has IC90 value of 9.372 μg/ml. The derived second order QSAR model favors moderate molecular surfaces in a combination with electronaccepting substituents in the aromatic hydrazone moiety.

A topological-mathematical model obtained by linear discriminant analysis has been used to the search of new nonsteroidal antinflammatory drugs (NSAIDs). After carrying out an in silico screening based on such a model, on the Aldrich database, new structures potentially active were selected. Among these structures stand fourteen compounds, from which only one had been previously recorded as NSAID in the literature. The experimental tests performed on the remaining substances demonstrated that several compounds showed either in vitro or in vivo or both activity. Moreover, four compounds, namely 1,3-bis(benzyloxycarbonyl)-2-methyl-2-thiopseudourea, 4,6-dichloro-2-methylthio-5-phenylpyrimidine, 2-chloro-2',6'-acetoxylidide and trans-1,3-diphenyl-2-propen-1-ol, showed a significant in vivo antinflammatory activity as compared to the reference drug (indomethacin). These results reinforce the role of Molecular Topology as a useful tool for drug discovery.

In the present paper, we describe the synthesis and biological evaluation for a series of novel 6,9-disubstituted 2-methyl-1,2,3,4,5,6-hexahydroazepino[4,3-b]indoles. These compounds represent unique bioisosteric analogues of Dimebon ™ with promising biological activity against a panel of various targets including some GPCR family members.

The development of hybrid compounds containing limonene- and recognized anti-T. cruzi-heterocycleframeworks is described. The six new compounds displayed broad antitrypanosomal activities having 5-nitrofuran and 5- nitroindazole derivatives, the best profiles. In addition, a 5-nitroindazole derivative evaluated against a panel of fungi exhibited relevant activities. Knowing that free-radical-production operates as one of the mechanisms of action on these heterocycles, we studied a potential extra-mechanism, membrane-sterols changes. Non-relevant T. cruzi squalene accumulation was observed for any of the tested hybrid-limonene derivatives.

Ten 1-benzenesulfonyl-1,2,3,4-tetrahydroquinoline (BSTHQ) were synthesized and characterized and their antiprotozoal activities were investigated. This small library was designed by combining two chemical moieties that are known to be biologically active by itself. The BS group seems to be favorable for the antiparasitic activity, since the derivatives presented lower IC50 value than the precursor heterocycle. Most compounds were moderately active against T cruzi, but 3 showed a promising IC50 value (9.76μM) with low cytotoxicity (L6). Also, 3, 6 and 9 showed interesting activity and reasonable selectivity against P. falciparum. These derivatives are considered as lead scaffolds and merit further exploration through structure optimization.

A series of 3-(2-(1-methoxynaphthalen-2-yl)-2-oxoethyl) quinazolinone derivatives (8a-k) were designed and synthesized. Their anticoccidial activities were evaluated against Eimeria tenella in vivo. The results indicated that compounds 8a, 8b and 8e exhibited anticoccidial activity against Eimeria tenella in the chicken's diet with a dose of 18 mg/Kg.