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8-Chloro-1-(2?,4?-dichlorophenyl)-N-piperidin-1-yl-1,4,5,6-tetrahydrobenzo[6,7]cyclohepta[1,2-c]pyrazole-3-carboxamide 9a was discovered as potent and selective CB1 antagonist by part of our group few years ago. In particular it was reported to have an affinity towards the CB1 cannabinoid receptor (CB1R), expressed as Ki, of 0.00035 nM. Nevertheless significantly divergent data were reported for the same compound from other laboratories. To unequivocally define the receptor profile of 9a, we have critically reviewed both its synthesis approach and binding data. Here we report that, in contrast to our previously reported data, 9a showed a Ki value for CB1R in the order of nanomolar rather than of fentomolar range. The new determined receptor profile of 9a was also ascertained for analogue derivatives 9b-i, as well as for 12. Moreover, the structural features of the synthesized compounds necessary for CB1R were investigated. Amongst the novel series, effects on CB1R intrinsic activity was highlighted due to the substituents at the position 3 of the pyrazole ring of the 1,4,5,6-tetrahydrobenzo[6,7]cyclohepta[1,2-c]pyrazole scaffold. Although the cannabinoid receptor profile of 9a was reviewed in this work, the relevance of this compound in CB1R antagonist based drug discovery is confirmed.

Novel 1,4-dihydropyrazolo[3,4-a]pyrrolizine-, 4,5-dihydro-1H-pyrazolo[4,3-g]indolizine- and 1,4,5,6-tetrahydropyrazolo[3,4-c]pyrrolo[1,2-a]azepine-3-carboxamide based compounds were designed and synthesized for cannabinoid CB1 and CB2 receptor interaction. Any of the new synthesized compounds showed high affinity for CB2 receptor with Ki values superior to 314 nM, whereas some of them showed moderate affinity for CB1 receptor with Ki values inferior to 400 nM. 7-Chloro-1-(2,4-dichlorophenyl)-N-(homopiperidin-1-yl)-4,5-dihydro-1H-pyrazolo[4,3-g]indolizine-3-carboxamide (2j) exhibited good affinity for CB1 receptor (KiCB1 = 81 nM) and the highest CB2/CB1 selectively ratio (>12). Docking studies carried out on such compounds were performed by using the hCB1 X-ray in complex with the close pyrazole analogue AM6538, and disclosed specific pattern of interactions related to the tricyclic pyrrolopyrazole scaffolds as CB1 ligands. This article is protected by copyright. All rights reserved.

Novel 1,4-dihydropyrazolo[3,4-a]pyrrolizine-, 4,5-dihydro-1H-pyrazolo[4,3-g]indolizine- and 1,4,5,6-tetrahydropyrazolo[3,4-c]pyrrolo[1,2-a]azepine-3-carboxamide-based compounds were designed and synthesized for cannabinoid CB

Considering the interesting pharmacological profile of the delta (?) selective opioid agonist compound SNC-80, conformationally constrained analogs containing two diazatricyclodecane ring systems in place of dimethylpiperazine core motif were synthesized. The compounds showed subnanomolar or low nanomolar ? opioid receptor binding affinity. Depending upon the substituents on the diazatricyclodecane ring, these compounds displayed varying selectivity for ? opioid receptor over ? and ? receptors. Amongst the novel compounds, 1Aa showed the more interesting biological profile, with higher ? affinity and selectivity compared to SNC-80. The ? receptor agonist profile and antinociceptive activity of 1Aa were confirmed using ex-vivo (isolated mouse vas deferens) and in vivo (tail flick) assays. © 2013 Elsevier Masson SAS. All rights reserved.

Synthetic tubulysins 24a-m, containing non-hydrolysable N-substituents on tubuvaline (Tuv), were obtained in high purity and good overall yields using a multistep synthesis. A key step was the formation of differently N-substituted Ile-Tuv fragments 10 by using an aza-Michael reaction of azido-Ile derivatives 8 with the ,-unsaturated oxo-thiazole 5. A structure-activity relationship study using a panel of human tumour cell lines showed strong anti-proliferative activity for all compounds 24a-m, with IC50 values in the sub-nanomolar range, which were distinctly lower than those of tubulysinA, vinorelbine and paclitaxel. Furthermore, 24a-m were able to overcome cross-resistance to paclitaxel and vinorelbine in two tumour cell lines with acquired resistance to doxorubicin. Compounds 24e and 24g were selected as leads to evaluate their mechanism of action. In vitro assays showed that both 24e and 24g interfere with tubulin polymerization in a vinca alkaloid-like manner and prevent paclitaxel-induced assembly of tubulin polymers. Both compounds exerted antimitotic activity and induced apoptosis in cancer cells at very low concentrations. Compound 24e also exhibited potent antitumor activity at well tolerated doses on in vivo models of diffuse malignant peritoneal mesothelioma, such as MESOII peritoneal mesothelioma xenografts, the growth of which was not significantly affected by vinorelbine. These results indicate that synthetic tubulysins 24 could be used as standalone chemotherapeutic agents in difficult-to-treat cancers.

A number of tin(II) complexes, prepared in situ from tin(II) triflate and pyridine derivatives (2,2′:6′,2″-terpyridine, 1,10-phenanthroline, 2,2′-bipyridine, dipyridylmethane, 2-(thiophen-2-yl)pyridine and 2-(2-diphenylphosphinophenyl)-5,6,7,8-tetrahydroquinoline), have been used as chiral catalysts for the reduction of acetophenone in the presence of polymethylhydrosiloxane (PMHS). Yields up to 82% and enantioselectivities up to 19% have been obtained.

Here we report the investigation of diazabicycloalkane cores as potential new scaffolds for the development of novel analogues of the previously reported diazatricyclodecane selective delta (?) opioid agonists, as conformationally constrained homologues of the reference ? agonist (+)-4-[(?. R)-?((2. S,5. R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,. N-diethylbenzamide (SNC80).In particular, we have simplified the diazatricyclodecane motif of ? opioid agonist prototype 1a with bridged bicyclic cores. 3,6-diazabicyclo[3.1.1]heptane, 3,8-diazabicyclo[3.2.1]octane, 3,9-diazabicyclo[3.3.1]nonane, 3,9-diazabicyclo[4.2.1]nonane, and 3,10-diazabicyclo[4.3.1]decane were adopted as core motifs of the novel derivatives. The compounds were synthesized and biologically assayed as racemic (3-5) or diastereoisomeric (6,. 7) mixtures.All the novel compounds 3-7 showed ? agonism behaviour and remarkable affinity to ? receptors. Amongst the novel derivatives, 3,8-diazabicyclo[3.2.1]octane based compound 4 evidenced improved ? affinity and selectivity relative to SNC80.

8-Chloro-1-(20,40-dichlorophenyl)-N-piperidin-1-yl-1,4,5,6-tetrahydrobenzo[6,7]cyclohepta[1,2-c]pyrazole- 3-carboxamide 9a was discovered as potent and selective CB1 antagonist by part of our group few years ago. In particular it was reported to have an affinity towards the CB1 cannabinoid receptor (CB1R), expressed as Ki, of 0.00035 nM. Nevertheless significantly divergent data were reported for the same compound from other laboratories. To unequivocally define the receptor profile of 9a, we have critically reviewed both its synthesis approach and binding data. Here we report that, in contrast to our previously reported data, 9a showed a Ki value for CB1R in the order of nanomolar rather than of fentomolar range. The new determined receptor profile of 9a was also ascertained for analogue derivatives 9b-i, as well as for 12. Moreover, the structural features of the synthesized compounds necessary for CB1R were investigated. Amongst the novel series, effects on CB1R intrinsic activity was highlighted due to the substituents at the position 3 of the pyrazole ring of the 1,4,5,6-tetrahydrobenzo[6,7]cyclohepta[1,2-c] pyrazole scaffold. Although the cannabinoid receptor profile of 9a was reviewed in this work, the relevance of this compound in CB1R antagonist based drug discovery is confirmed

Tubulysins are cytotoxic natural products with promising anti-cancer properties, originally isolated from myxobacterial cultures. Structurally, tubulysins are tetrapeptides, incorporating three unusual (Mep, Tuv and Tup) and one proteinogenic amino acid (Ile). Here we describe the synthesis and structure-activity relationship studies of novel tubulysin U and V analogues, with variations in the central Tuv fragment, which is known to be of paramount importance for tubulysins' potency and hence cytotoxicity, but has seldom been modified in previous studies. Specifically, we replaced the natural iso-propyl and acetoxy functionalities with other structurally related groups. In general, the new analogues showed much lower potency relative to native tubulysin U. However, one of the synthetic analogues (1f) having a MOM function replacing the acetyl group exhibited a 22 nM IC50 on the HT-29 cell line which is comparable to the IC(50) displayed by tubulysin U (3.8 nM). Furthermore, the synthetic methodology reported herein was found to be flexible enough to deliver different core-modified tubulysin analogues and hence may be regarded as a scalable and convenient strategy for the chemical generation of novel tubulysin analogues.

In spite of rimonabant's withdrawal from the European market due to its adverse effects, interest in the development of drugs based on CB1 antagonists is revamping on the basis of the peculiar properties of this class of compounds. In particular, new strategies have been proposed for the treatment of obesity and/or related risk factors through CB1, antagonists, i.e. by the development of selectively peripherally acting agents or by the identification of neutral CB1 antagonists. New compounds based on the lead 031 antagonist/inverse agonist rimonabant have been synthesized with focus on obtaining neutral CB1 antagonists. Amongst the new derivatives described in this paper, the mixture of the two enantiomers (+/-)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-3-(2-cyclohexyl-1-hydroxyethyl)-4-methyl-1H-pyrazole ((+/-)-5), and compound 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-3-[(4-2-cyclohexyl-1-fluorovinyl]-4-methyl-1H-pyrazole ((Z)-6), showed interesting pharmacological profiles. According to the preliminary pharmacological evaluation, these novel pyrazole derivatives showed in fact both neutral CB1 antagonism behaviour and significant in vivo activity towards food intake. (C) 2013 Elsevier Masson SAS. All rights reserved.

This study investigates the molecular mechanisms and the center-periphery cross talk underlying the anti-obesity effect of the cannabinoid receptor 1 (CB 1 ) antagonist/inverse agonist rimonabant in diet-induced obese (DIO) mice exposed to a 31 days chronic treatment with the drug. Present data showed a significant and stable weight loss both in animals treated with rimonabant 10 mg/kg by oral gavage exposed to a high fat diet (SRFD) and in vehicle treated mice switched to a regular chow (VEND) with respect to vehicle fat diet fed mice (VEFD). Caloric intake was significantly lowered in SRFD and VEND during the first two and four days, respectively, then reaching the VEFD consume throughout the treatment. The drop of body weight was accompanied by leptin mRNA decrease in visceral fat tissue both in VEND and SRFD, as revealed by Real time PCR analysis. No difference in CB 1 mRNA receptor expression in hypothalamus and in visceral fat tissue among groups was observed. Leptin receptors were decreased in the hypothalamus of SRFD but not of VEND mice. Moreover, in SRFD and VEND mice the expression of orexigenic genes Neuropeptide Y and Agouti Related Protein (AGRP) was increased, while anorexigenic ones, Pro-OpioMelanoCortin (POMC) and Cocaine-and-Amphetamine-Regulated Transcript (CART) displayed no alteration in any group. This data contribute to clarify the molecular basis of the anti-obesity properties of rimonabant, underlying the role of the peripheral modulators which affect central circuits involved in the regulation of food intake and energy homeostasis.

A series of analogues 2a–i related to 3-{2-[bis-(4-fluorophenyl)methoxy]ethyl}-8-(1H-indol-2-ylmethyl)-3,8-diazabicyclo[3.2.1]octane (1) in which the 3,8-diazabicyclo[3.2.1]octane core was replaced by 3,6-diazabicyclo[3.1.1]heptane ring system has been synthesized and evaluated for their ability to inhibit DA reuptake into striatal nerve endings (synaptosomes). Biological data showed that compound 2a, the closest analogue of lead 1, possessed an increased reuptake inhibition activity over 1 (2a, Ki = 5.5 nM). Replacement of the indole ring with bioisosteric aromatic rings—benzothiophene (2b), benzofurane (2c), or indene (2d)—resulted, with the exception of 2d, in a double digit nanomolar activity. Changing the indenyl moiety of 2d with simplified aryl groups led to compounds 2e–h which displayed a similar or slightly decreased activity with respect to the ground term. Naphthalene derivative (2i) demonstrated a weaker activity than aromatic analogues.

New analogues (2a-p) of the previously reported CB(2) ligands 6-methyl- and 6-chloro-1-(2',4'-dichlorophenyl)-N-piperidin-1-yl-1,4-dihydroindeno[1,2-c]pyrazole-3-carboxamides (1a,b) have been synthesized and evaluated for cannabinoid receptor affinity. One example, 1-(2',4'-dichlorophenyl)-6-methyl-N-cyclohexyilamine-1,4-dihydroindeno[1,2-c] pyrazole-3-carboxamide (2a) was shown to have single digit nanomolar affinity for cannabinoid CB(2) receptors. Furthermore, compounds 2a and 2b, as well as lead structures 1a,b, were also shown to be agonist in an in vitro model based on human promyelocytic leukemia HL-60 cells.

A protocol for the synthesis of quinolines substituted on both pyridine and benzo-fused rings is reported. The method is based on the formylation of a substituted N-(tert-butoxycarbonyl)aniline followed by direct cyclisation and aromatisation of the intermediate product obtained by condensation of the formed N-Boc o-aminobenzaldehyde with an enolisable carbonyl compound. Yields up to 88% have been obtained.

In an effort to improve diazabicycloalkane-based opioid receptor ligands, N -3(6)-arylpropenyl- N -6(3)-propionyl-3,6-diazabicyclo[3.1.1]heptanes ( 3A , Ba – i ) were synthesized and their affinity and selectivity towards μ-, δ- and κ-receptors were evaluated. The results of the current study revealed a number of compounds ( 3Bb , 3Bg and 3Bh ) having a high affinity for μ ( K i at μ-receptors ranging from 2.7 to 7.9 nM) versus δ ( K i at δ-receptors >2000 nM) and versus κ ( K i at κ-receptors >5000 nM) receptors. Molecular modelling carried out on the pair 3Aa/3Ba and on the 3Bh was consistent with the hypothesis that the two series of compounds 3A and 3B interact with the μ-receptor in very different ways.

A series of analogues of 8-chloro-1-(2',4'-dichlorophenyl)-N-piperidin-1-yl-1,4,5,6-tetrahydrobenzo[6,7]cyclohepta[1,2-c]pyrazole-3-carboxamide 4a (NESS 0327) (Ruiu, S.; Pinna, G. A.; Marchese, G.; Mussinu, J. M.; Saba, P.; Tambaro, S.; Casti, P.; Vargiu, R.; Pani, L. Synthesis and Characterization of NESS 0327: A Novel Putative Antagonist of CB1 Cannabinoid Receptor. J. Pharmacol. Exp. Ther. 2003, 306, 363-370) was synthesized and evaluated for their affinity to cannabinoid receptors. Depending on the chemical modification of the lead structure that was chosen, compounds 4b, 4c, 4i, 4l, and 4m still proved to be potent binders of the CB1 receptor. Moreover, several analogues (4c, 4d, 4e, and 4m) demonstrated superior CB2 receptor binding affinities compared to the parent ligand. Compounds 4b, 4c, 4i, and 4l displayed the most promising pharmacological profiles, having the highest selectivity for CB1 receptors with Ki(CB2) to Ki(CB1) ratios of 11,250, 2000, 3330 and 4625, respectively. Compound 4c increased the intestinal propulsion in mice and antagonized the effect induced by the CB1 receptor agonist WIN 55,212-2. Finally, molecular modeling studies were carried out on a set of tricyclic pyrazoles (2a-4a) and on rimonabant 1 (SR141716A), indicating that high CB1 receptors affinities were consistent for the tricyclic derivatives, both with a nonplanar geometry of the tricyclic cores and with a precise orientation of the substituent (chlorine) on this ring system.

The circadian rhythms of histatins 1, 3, 5, of statherin and uric acid were investigated in whole human saliva. Histatins showed a rhythm approximately synchronous with salivary flow rate (acrophas...