In drug discovery there are several approaches to lead generation and one traditional approach involves the synthesis and screening of a structurally diverse compound library against a number of biological targets to identify high affinity lead compounds. The use of a `privileged' structure-based compound library represents a viable approach that could lead to drug like lead compounds. Privileged structures are defined as those ligand substructures that may be used to generate high affinity leads for more than one type of receptor. Examples of privileged structures include phenyl substituted monocycles such as biphenyls, diphenyl methane derivatives, 1,4-dihydropyridines, fused ring systems such as chromones, quinoxalines, quinazolines, 2-benzoxazolones, indoles, benzimidazoles and benzofurans. There are several instances in the literature describing the development of compound libraries based on privileged structures with reportedly high hit rates. Privileged structure based approaches has been used with notable success in the identification of high affinity ligands especially for G-protein coupled receptors (GPCRs). The scaffold 2-aminothiazole (fused and non-fused) may be considered a privileged structure because of its occurrence in a wide variety of pharmaceuticals. The scaffold is found in antibacterials, anti-inflammatory agents, glutamate transporter (GLT-1) modulators, serotonin and muscarinic ligands. The present study involves the synthesis of a 2-aminothiazole (fused and non-fused) based compound library (60 compounds) by incorporating bioactive fragments shown to produce hits in the biological targets of interest. Microwave assisted organic synthesis (MAOS) has been employed at key steps of scaffold synthesis as well as in Suzuki coupling to generate the target aminothiazoles. Preliminary biological screening has resulted in the identification of some promising lead compounds. Trifluoromethoxy substituted aminothiazoles were found to be potent antimicrobials with MIC values in the range of 4-16 microgram/ml. Furanone based aminothiazoles showed affinity for muscarinic receptors. Piperidine based aminothiazoles showed greater than 90% of control (8-OH-DPAT) specific agonist response at the 5-HT1A receptor subtype. The Clog P values of the most potent antimicrobials were found to be in the range of 4.5-6.2 indicating the high lipophilicity of the compounds. High lipophilicity is known to cause solubility issues that may hamper future development. Therefore in an effort to make compounds with intermediate lipophilicity, the phenyl core of the potent aminothiazoles will be replaced with pyridine core using literature procedures (Pyridine core containing aminothiazoles showed Clog P < 4). Future plans include expanding the library, improving the yields of compounds and to evaluate the compounds as modulators of glutamate transporter (GLT-1). The work could be extended to include other privileged structures such as 2-aminooxazole, 2-aminobenzoxazole, 2-aminoimidazole and 2-aminobenzimidazole. These mono and bicyclic heterocyles may be considered bioisosteres of 2-aminothiazole. / Pharmaceutical Sciences

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This work was conducted to evaluate the activity anti-inflammatory and antinocieptive two series of derivatives of N-acilidrazonas (NAH) rationally designed and synthesized by LASSBio® UFRJ. The first series consists of four compounds, being two metal complexes generated from the coordination of prototypes LASSBio-1064 and LASSBio-466 and second prototype LASSBio-1064 and LASSBio-466. The second series comprised eight derivatives, designed as structural analogues of piroxicam. Were performed nociception models of functional chemical (writhing induced by acetic acid 0.1 N, formalin test), thermal nociception (hot plate test), cell migration assay (peritonitis induced by zymosan A and / or induced by carrageenin) assay evaluation of inhibition of COX-1/COX-2. All compounds and standards were administered 40 min before starting the test (p.o) at a dose of 100 mmol / kg. In the first series, Animal constriction induced by acetic acid was inhibited by all the compounds studied, highlighting the [Zn(LASSBio-466)H2O]2 and H2LASSBio-1064 that inhibited (p˂0.01) at 82.7 % (p˂0.01) and 81.3% (p˂0.01) the number of writhes, as the standard drug (dipyrone) inhibited 77.7% (p˂0.01). In the first phase of the formalin test H2LASSBio-466 and H2LASSBio-1064 reduced the latency time to lick 53.1% (p ˂ 0.05) and 46.5% (p˂0.01), respectively. In the second phase of the test compounds H2LASSBio-1064 and [Zn(LASSBio-466)H2O]2 reduced the latency time to lick at 48.5% (p˂0.05) and 37.3% (p˂0.05), respectively. All compounds showed levels of inhibition of peritonitis induced by zymosan comparable or superior to indomethacin (drug standard). In the second series, the compounds were active in the assay of writhing induced by acetic acid highlighting the LASSBio-1638, LASSBio-1604 and LASSBio-1639 inhibited the contortions that abdmoniais in 84.0% (p˂0.01), 82.7% (p˂ 0.01) and 90.4% (p˂ 0.01), respectively, whereas piroxicam (drug standard), inhibited by 95.4% (p˂0.01) . In the formalin test, only LASSBio-1617 significantly inhibited the nociceptive activity in the first stage by 58.2% (p<0.01). In the second phase the LASSBio-1637, LASSBio-1638 inhibited the nociceptive activity in 60.0% (p<0.05) and 54.2% (p<0.05), respectively, and piroxicam inhibited 53.9 % (p<0.01). In models of acute inflammation, the compounds showed inhibitory activity against cell migration similar to or greater than the piroxicam. In the trial of carrageenan-induced acute peritonitis compounds LASSBio-1604LASSBio-1637, LASSBio-1638 and LASSBio-1639 inhibited cell migration by 74.2% (p˂ 0.01), 73.2% (p˂0.01), 77.6% (p˂ 0.01) and 81.8% (p ˂ 0.01), respectively, where as piroxicam inhibited by 25.5% (p˂0.01). The compounds LASSBio-1637, LASSBio-1638-1639 and LASSBio highlighted in the testing of acute peritonitis induced by zymosan A, inhibiting cell migration in 78.6% (p˂0.01), 81.2% (p ˂ 0.01) and 82.7% (p ˂ 0.01), showing that, in this essay, more active than piroxicam (57.3%). LASSBio-1604 and LASSBio-1617 inhibited the enzyme COX in vitro, presenting, respectively, IC50 values of 0.22 M and 0.28 M for inhibition of COX-1 and 0.24 M and 0.26 M for inhibition of COX-2. Pharmacological Evaluation results suggest that in the first series, the coordination of zinc (II) is a good strategy to improve the antinociceptive activity of the compound H2LASSBio-466 associated with inflammatory pain, and in the second series, all compounds exhibit antinociceptive and anti-inflammatory similar or superior to piroxicam. / Neste trabalho foi realizado a avaliação da atividade antinocieptiva e anti-inflamatória de duas séries de derivados N-acilidrazonas (NAH) racionalmente planejadas e sintetizados pelo LASSBio® da UFRJ. A primeira serie é formada de 4 compostos, sendo 2 complexos metálicos gerados a partir da coordenação dos protótipos LASSBio-466 e LASSBio-1064 e 2 protótipos LASSBio-466 e LASSBio-1064. A segunda série formada por 8 derivados, desenhados como análogos estruturais do piroxicam. Foram realizados modelos funcionais de nocicepção química (contorção abdominal induzida por ácido acético 0,1N, ensaio de formalina), nocicepção térmica (ensaio da placa quente), ensaio de migração celular (peritonite induzido por zymosan A e/ou induzido por carragenina) ensaio de avaliação de inibição da COX-1/COX-2. Todos os compostos e padrões foram administrados 40 min antes do início ensaio (vo) na dose de 100 μmol/kg. Na primeira série, a constrição animal induzida por ácido acético foi inibida por todos os compostos estudados, destacando-se o [Zn(LASSBio-466)H2O]2 e H2LASSBio-1064 que inibiram (p˂0,01) em 82,7% (p˂0,01) e 81,3% (p˂0,01) o numero de contorções, enquanto o fármaco-padrão (dipirona) inibiu em 77,7% (p˂0,01). Na primeira fase do ensaio de formalina o H2LASSBio-1064 e H2LASSBio-466 reduziram o tempo de latência de lambida em 53,1% (p˂0,05) e 46,5% p˂0,01), respectivamente. Já na segunda fase do ensaio os compostos H2LASSBio-1064 e [Zn(LASSBio-466) H2O]2 reduziram o tempo de latência de lambida em em 48,5% (p˂0,05) e 37,3% (p˂0,05), respectivamente. Todos os compostos mostraram níveis de inibição da peritonite induzida por zymosan comparáveis ou superiores à indometacina (fármaco padrão). Na segunda série, os compostos mostraram-se ativas no ensaio de contorções abdominais induzida por acido acético destacando-se o LASSBio-1638, LASSBio-1639 e LASSBio-1604 que inibiram as contorções abdmoniais em 84,0% (p˂0,01), 82,7% (p˂0,01) e 90,4% (p˂0,01), respectivamente, ao passo que o piroxicam (fármaco padrão) inibiu em 95,4% (p˂0,01). No teste de formalina, apenas LASSBio-1617 inibiu significativamente a atividade nociceptiva na primeira fase em 58,2% (p <0,01). Na segunda fase o LASSBio-1637, LASSBio-1638 inibiram a atividade nociceptiva em 60,0% (p <0,05), e 54,2% (p <0,05), respectivamente, e o piroxicam inibiu em 53,9% (p <0,01). Em modelos de inflamação aguda, os compostos apresentaram atividade inibitória sobre a migração celular semelhante ou maior que o piroxicam. No ensaio de peritonite aguda induzida por carragenina os compostos LASSBio-1604, LASSBio-1637, LASSBio-1638 e LASSBio-1639 inibiram a migração celular em 74,2% (p˂0,01), 73,2% (p˂0,01), 77,6% (p˂0,01) e 81,8% (p˂0,01), respectivamente, ao passo que o piroxicam inibiu 25,5% (p˂0,01). Os compostos LASSBio-1637, LASSBio-1638 e LASSBio-1639 destacaram-se no ensaio de peritonite aguda induzida por zymosan A, inibindo a migração celular em 78,6% (p˂0,01), 81,2% (p˂0,01) e 82,7% (p˂0,01), mostrando-se, nesse ensaio, mais ativos que o piroxicam (57,3%). LASSBio-1604 e LASSBio-1617 inibiram a enzima COX in vitro, apresentando, respectivamente, valores de CI50 de 0,22 M e 0,28 M para inibição de COX-1 e 0,24 M e 0,26 M para inibição de COX-2. Os resultados da avaliação farmacológica sugerem que, na primeira série, a coordenação do zinco (II) é uma boa estratégia para melhorar a atividade antinociceptiva do composto H2LASSBio-466 associada a dor inflamatória, e na segunda série, que todos compostos apresentam atividades antinociceptiva e anti-inflamatória semelhantes ou superiores ao piroxicam.

Les pyrrolodiazépinones ont des activités biologiques intéressantes sur différents récepteurs biologiques, ce qui en font une cible de choix pour développer de nouvelles petites molécules biologiquement actives. Une méthodologie en solution a été développée pour synthétiser des pyrrolo[3,2-e][1,4]diazépin-2-ones, qui utilise la réaction de Pictet-Spengler pour former le cycle diazépinone, comme réaction clé. Il a été démontré que le pyrrolo[3,2-e][1,4]diazépin-2-one mime un tour-γ inverse par l’analyse de cristaux par rayon X. Cette méthodologie a été transposée sur trois types de support, soit la résine de Merrifield, de Wang et un support soluble (TAP). Le système urotensinergétique joue un rôle dans certaines pathologies du système cardiovasculaire, comme l’hypertension artérielle, l’insuffisance cardiaque et l’athérosclérose. Le système urotensinergétique est exprimé dans le système circulatoire, extractoire et le système nerveux central et comprend l’UII, l’URP et le récepteur UT. L’UII et l’URP humains sont composés respectivement des séquences d’acides aminés : H-Glu-Thr-Pro-Asp-c[Cys-Phe-Trp-Lys-Tyr-Cys]-Val-OH et H-Ala-c[Cys-Phe-Trp-LysTyr-Cys]-Val-OH. L’UII est le peptide vasoconstricteur le plus puissant connu à ce jour, dont l’URP est son isoforme. Les deux peptides ont des effets biologiques différents et on peut supposer qu’ils jouent un rôle distinct dans certaines pathologies. Il a été démontré que la partie active de l’UII est composée du tripeptide : Trp-Lys-Tyr. Dans l’URP, il a été démontré que ce tripeptide forme un tour-γ inverse, ce qui fait du récepteur UT une bonne cible biologique pour tester une librairie de pyrrolo[3,2-e][1,4]diazépin-2-ones, reprenant le tripeptide Trp-Lys-Tyr. Dernièrement, l’équipe du professeur David Chatenet a mis au point un peptide, l’urocontrin en remplaçant le segment Trp par un groupement biphénylalanine, qui a démontré un comportement spécifique comme antagoniste du récepteur UT. La Librairie de pyrrolo[3,2-e][1,4]diazépin-2-ones est basée sur la séquence TrpLys-Tyr de l’UII et de l’URP et de la séquence Trp-Lys-Bip de l’urocontrin. La synthèse de la librairie est faite sur la résine de Wang. La chaîne latérale de Tyr est mimée en utilisant la tyramine, Lys et Orn sont utilisés et la chaîne latérale de Trp a été reproduite II en utilisant le biphényle (comme dans l’urocontrin), le 1-naphthyle et le 2-naphthyle, sont introduits en employant les aldéhydes respectifs dans la réaction de Pictet-Spengler, ce qui donne les pyrrolo[3,2-e][1,4]diazépin-2-ones insaturés et les saturés S- et R-. L’évaluation de l’activité biologique des pyrrolo[3,2-e][1,4]diazépin-2-ones obtenues sur le récepteur UT se fait par des tests in vitro et ex vivo. Les tests in vitro consistent en un essai de liaisons sur des cellules CHO exprimant le récepteur UT en employant hUII-125I, comme contrôle radiomarqé. Les tests ex vivo sont effectués sur des aortes de rats pour mesurer la capacité à induire des contractions ou de moduler les contractions induites par hUII et URP. Certains R-pyrrolo[3,2-e][1,4]diazépin-2-ones causent une réduction de 50% du signal radioactivité du hUII-125I. Les pyrrolo[3,2-e][1,4]diazépin-2-ones ne montrent guère d’activité ex vivo, mais ils ont la capacité de moduler les contractions induites par l’hUII et l’URP. Par exemple, l’analogue Lys R-saturé avec le biphényle inhibe toutes les contractions de l’aorte à 14 µM avec un pKb de 5,54 à 4 µM, sans influencer les contractions de l’aorte induites par l’URP. Les pyrrolo[3,2-e][1,4]diazépin-2-ones ont une sélectivité pour le système urotensinergétique et sont inactifs sur le récepteur de l’endotheline-1. Les pyrrolo[3,2-e][1,4]diazépin-2-ones sont les premières petites molécules qui peuvent moduler l’activité biologique de l’UII et URP et offrir un potentiel intéressant comme outil pour étudier le système urotensinergétique. / The pyrrolodiazepinones have interesting biological activities on various biological receptors, which makes them a prime target for developing new biologically active small molecules. A methodology in solution had been developed for synthesizing pyrrolo[3,2-e][1,4]diazepin-2-ones, which utilized the Pictet-Spengler condensation as the key reaction to form the diazepinone ring. Pyrrolo[3,2-e][1,4]diazepin-2-ones were found to mimic an inverse γ-turn conformation by X-ray crystallographic analysis. The methodology was subsequently implemented on three types of support: Merrifield resin, Wang resin and the soluble TAP support. The urotensinergic system plays a role in certain diseases of the cardiovascular system, such as hypertension, heart failure and atherosclerosis. The urotensinergic system is expressed in the circulatory system, excretory and central nervous systems and includes the endogenous ligands urotensin II (UII) and urotensin II-related peptide (URP), and the urotensin receptor UT. The ligands UII and human URP are composed of the respective amino acid sequences: H-Glu-Thr-Pro-Asp-c[Cys-Phe-Trp-Lys-Tyr-Cys]-Val-OH and H-Ala-c[Cys-Phe-Lys-Tyr-Trp-Cys]-Val-OH. The peptide UII is the most potent vasoconstrictor known to date. The two peptides have different biological effects and may exhibit distinct roles in certain diseases. Their common Trp-Lys-Tyr sequence is believed to play an important role in the activity of UII and URP, and has been suggested to adopt an inverse γ-turn conformation. Notably, the laboratory of Professor David Chatenet developed the UT receptor antagonist peptide urocontrin by replacing the Trp residue by biphenylalanine (Bip) in URP. A library of pyrrolo[3,2-e][1,4]diazepin-2-one analogs was thus designed to mimic the inverse γ-turn sequence and targeted against UT. The pyrrolo[3,2-e][1,4]diazepin-2-one library was designed based on the Trp-Lys-Tyr sequence of UII and URP, and Trp-Lys-Bip sequence of urocontrin. The synthesis of the pyrrolo[3,2-e][1,4]diazepin-2-one library was achieved on Wang resin. The side chain of Tyr was mimicked using tyramine, Lys and Orn were used as the basic amino acid component, and the side chain of Trp was replicated using biphenyl (as in urocontrin) 1-naphthyl and 2-naphthyl groups that were introduced by employing their respective aldehydes in a Pictet-Spengler reaction, which furnished unsaturated and saturated S- and R-pyrrolo[3,2-e][1,4]diazepin-2-ones. Evaluation of the biological activity of the pyrrolo[3,2-e][1,4]diazepin-2-ones on the UT receptor was performed in vitro and ex vivo. Tests in vitro measured binding in CHO-cells which expressed UT by employing hUII-125I as radiolabeled control. In rat aorta, ex vivo tests measured capacity to induce contraction, or modulate the contractions induced by hUII and URP. Certain R-pyrrolo[3,2-e][1,4]diazepin-2-ones caused an up to 50% reduction of the radioactive signal of hUII-125I. Pyrrolo[3,2-e][1,4]diazepin-2-ones exhibited little activity ex vivo; however, they modulated contractions induced by hUII and URP. For example, the saturated R-analog possessing lysine and a biphenyl side chain inhibited completely hUII-induced contractions of the aorta at 14 µM with a pKb of 5.54 at 4 µM, without influencing URP-induced contractions. Pyrrolo[3,2-e][1,4]diazepin-2-ones were selective for the urotensinergic system and inactive on the related receptor endothelin-1. Pyrrolo[3,2-e][1,4]diazepin-2-ones represent the first small molecules that can differently modulate the biological activities of UII and URP, and offer interesting potential as tools for studying the urotensinergic system.