Синтетски пут за добијање 1,2,3,4-тетрахидрохиноксалинскo/пиперидинског трицикличног система

The synthetic route toward novel tricyclic, nitrogen-containing system is disclosed. Three novel compounds possessing structural features of 1,2,3,4-tetrahydroquinoxaline and decahydropyrido[3,4-b]pyrazine are synthesized starting from readily available precursors in six or seven steps, of which the last three or four steps respectively are diastereoselective. Key reaction steps include N-acylation, Hofmann rearrangement and ring-closing Buchwald– Hartwig reaction. Compounds trans-8, cis-12 and trans-12 are synthesized in order to prove that this novel, tricyclic system can be functionalized with various groups. Synthetic significance of this heterocyclic system lies in the possibility for the orthogonal functionalization of three different amino groups, allowing fine structural tuning.У овом раду представљена је синтеза новог трицикличног система који садржи азот. Три нова једињења код којих су комбиноване структурне карактеристике 1,2,3,4-тетрахидрохиноксалина и декахидропиридо[3,4-b]пиразина, добијена су полазећи од лако доступних прекурсора, у шест или седам фаза од којих су последње три или четири, редом, диастереоселективне. Кључне синтетичке трансформације укључују N-ациловање, Hofmann премештање и интрамолекулску Buchwald–Hartwig реакцију, као фазу у којој долази до циклизације. Једињења trans-8, cis-12 и trans-12 су синтетисана како би се представила могућност функционализације новог трицикличног система. Синтетички значај новог хетероцикличног система представљен је у могућности ортогоналне функционализације три различите амино групе, чиме се може постићи фино подешавање структуре

Homologo modelovanje strukture proteina

Knowledge of three-dimensional protein structure is of the paramount importance for determination of receptor and enzyme action mechanism in interaction with other molecules. In spite of growing number of solved 3D protein structures, number of determined protein sequences exceeds by far the number of defined spatial protein structures. Besides, sequence databases grow more rapidly then databases of 3D protein structures. When crystal protein structures or data obtained by NMR are not available, we have to reach for next 'best' possible solution - modeling of the protein spatial structure. One of the aspects that can be applied to obtain usable protein model is homology modeling. This method is based on the design of the three-dimensional structure of the unknown protein based on layout of the homolog protein of known 3D structure. To get a big picture of this method, in this text, we explained few aspects of homology modeling

Homologo modelovanje strukture proteina

Knowledge of three-dimensional protein structure is of the paramount importance for determination of receptor and enzyme action mechanism in interaction with other molecules. In spite of growing number of solved 3D protein structures, number of determined protein sequences exceeds by far the number of defined spatial protein structures. Besides, sequence databases grow more rapidly then databases of 3D protein structures. When crystal protein structures or data obtained by NMR are not available, we have to reach for next 'best' possible solution - modeling of the protein spatial structure. One of the aspects that can be applied to obtain usable protein model is homology modeling. This method is based on the design of the three-dimensional structure of the unknown protein based on layout of the homolog protein of known 3D structure. To get a big picture of this method, in this text, we explained few aspects of homology modeling

Uticaj osobina N-1 supstituenta na afinitet arilpiperazina prema vezivnom mestu 5-HT1A receptora

Scrotonin receptors (5-HTRs), especially the 5-HT1A subtype, have been the subject of intensive research for the past decade, due to their function in human physiology. Several structurally different classes of ligands are known to bind to the 5-HT1A receptor, but arylpiperazine derivatives are among the most important ligands. In the work, docking analyses were used to explain the binding affinities of a series of ligands with different N-1 substituent. All ligands had ill common the arylpiperazine structure, while the N-1 substituent was modified to investigate the influence of ligand structure on its binding affinity. The shape and size, as well as the rigidity of the substituents were altered to investigate the possible effects on the formation of the receptor - ligand complex.Serotoninski receptori su, a naročito 5-HT 1A pod tip, zbog značajne uloge u fiziologiji ljudskog organizma, predmet intenzivnog izučavanja tokom protekle decenije. Poznato je da se za 5-HT 1A receptor vezuje nekoliko strukturno različitih klasa liganada, ali su arilpiperazinski derivati među najznačajnijim. Da bi objasnili vezivanje serije liganada sa različitim N-1 supstituentima za receptor koristili smo analizu vezivanja (docking analizu). Svi ligandi su imali zajedničku arilpiperazinsku strukturu dok su im N-1 supstituenti modifikovani tako što je menjan oblik, veličina kao i krutost supstituenta da bi se istražio njihov eventualni uticaj na formiranje kompleksa receptor - ligand

Application of Hybrid Density Functional Theory in Calculation of Edge-to-Face Interactions of Receptor-Ligand System

Our previously described research on docking analysis of a series of isosteric N4-arylpiperazines on a model of 5-HT1A receptor was used earlier to investigate interactions of different ligands with the receptor binding site. Due to the limitations of molecular mechanics (MM) methods, docking analysis failed to give precise results about interactions that influence binding affinity of the ligands, but we presumed that aromatic-aromatic interactions, or edge-to-face, to be more precise, play an important role in the binding process. In order to further elaborate on this hypothesis, ab initio approach was used to calculate possible edge-to-face interactions on a model system and correlate them to ligand affinity. Obtained results indicate that those dispersive interactions can show notable influence on the binding of the ligands to 5-HT1A receptor. Stabilization energies of modeled receptor-ligand complex, calculated using Becke's "half-and-half" hybrid DFT method showed strong correlation with the affinity of investigated ligands towards 5-HT1A receptor

Uticaj disperzivnih interakcija na afinitet vezivanja liganada sa arilpiperazinskom funkcijom za dopaminski D2 receptor

Several isosteric 1,3-dihydro-5-[2-(4-aryl-l-piperazinyl)ethyl]-2H-benzinlidazole-2-thiones were used to investigate the interactions of different ligands with the binding site of the D2 receptor. Due to limitations of the simulation methods, docking analysis failed to show precisely the interactions that influence the binding affinity of the ligands. It is presumed that dispersive forces or more precisely edge-to-face interactions play an important role in the binding process, especially for the lipophilic part of the ligands. In order to confirm this hypothesis, ab initio calculations were applied on a model system in order to find the stabilization energies of potential edge-to-face interactions and then to correlate them with the ligand affinity. The obtained results indicate that there is a significant correlation between the strength of dispersive interactions and ligand affinity. It was shown that for the calculation of stabilization energies of modeled receptor-ligand complexes the Becke "half-and-half" hybrid DFT method can be used, thus speeding up the usually long calculation time and reducing the required computer strength.Nekoliko izosternih 1,3-dihidro-5-[2-(4-aril-1-piperazinil)etil]-2H-benzimidazol-2-tiona je korišćeno da bi se ispitale interakcije različitih liganada sa vezivnim mestom dopaminskog D2 receptora. Zbog ograničenja metoda korišćenih za simulaciju vezivanja, analiza ovih rezultata nije mogla da pokaže preciznije koje interakcije utiču na afinitet vezivanja liganada. Pretpostavljeno je da disperzivne sile, ili preciznije, tzv. edge-to-face interakcije, igraju značajnu ulogu u procesu vezivanja, naročito u lipofilnom delu liganda. Da bi se potvrdila ova hipoteza primenom ab initio izračunavanja na model sistem, pokušano je izračunavanje stabilizacione energije ovih interakcija i njeno dovođenje u vezu sa afinitetom liganada. Dobijeni rezultati ukazuju da postoji značajna korelacija između jačine disperzivnih interakcija i afiniteta liganda. Pokazano je da se pri izračunavanju stabilizacionih energija modelovanih kompleksa ligand-receptor može upotrebiti Beckeova 'half-and-half' hibridna DFT metoda, što značajno smanjuje vreme potrebno za izračunavanja i potrebne računarske resurse

Supplementary data for the article: Penjišević, J. Z.; Šukalović, V. V.; Andrić, D. B.; Roglić, G. M.; Šoškić, V.; Kostić-Rajačić, S. V. Synthesis, Biological, and Computational Evaluation of Substituted 1-(2-Methoxyphenyl)-4-(1-Phenethylpiperidin-4-Yl)Piperazines and 1-(2-Methoxyphenyl)-4-[(1-Phenethylpiperidin-4-Yl)Methyl]Piperazines as Dopaminergic Ligands. Archiv der Pharmazie 2016, 614–626. https://doi.org/10.1002/ardp.201600081

Supplementary material for: [https://doi.org/10.1002/ardp.201600081]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2286

Синтетички пут за синтезу потенцијалних, бивалентних лиганада који поседују опоидну и допамин Д2/Д3 фармакогфору

A scalable, cost-efficient and simple synthetic pathway towards potential bivalent opioid/dopamine receptor ligands was developed and optimized. Three novel compounds that contain both opioid and dopamine pharmacophores linked by the four methylene group chain were synthesized in 33, 35 and 39 % overall yield after a four-step synthetic route starting from three commercially available N-aryl piperazines. The anilino piperidine precursor was easily prepared in three steps, as previously published, starting from 4- piperidone. The synthesis presented in this paper could be of interest for heterocyclic and general organic chemistry. The newly designed compounds possessing two pharmacophores, opioid and D2/D3, are potentially useful pharmacological probes. Of particular interest would be the simultaneous binding to both opioid and D2/D3 receptors, and the resulting pharmacological responses may be useful for the further understanding of tolerance and dependence phenomena in opioid clinical use and/or abuse.Три нова једињења, која садрже опиоидну и допаминску фармакофору, спојене преко четири метиленске групе, синтетисанa су у четири фазе у укупном приносу од приближно 35 %, полазећи од три комерцијално доступна N-арилпиперазина. Анилино- пиперидински прекурсор је добијен у три једноставне реакционе фазе, полазећи од 4-пиперидона, према познатој литературној методи. Синтеза приказана у овом раду може бити од значаја за хетероцикличну и органску хемију у целини. Новосинтетисана једињења која поседују две фармакофоре, опиоидну и Д2/Д3, су потенцијално корисни супстрати за фармаколошка испитивања. Од посебног интереса може бити истовремено везивање за опиоидне и Д2/Д3 рецепторе, а резултујући фармаколошки одговор био би користан у даљем разумевању толеранције и зависности, као феномена везаних за кли- ничку употребу и/или злоупотребу опијата

Interaction of different third intracellular loop fragments of human dopamine d2l receptor with a-subunit of gi1 protein - prospective therapeutic application

In order to find the essential structural motif of the D2L dopamine receptor necessary for the interaction with a-subunit of Gi1 protein, four fragments of the third cytoplasmic loop (CPL3) of this receptor were cloned, expressed in E. coli and purified. After that, fusion proteins with glutathione-S-transferase (GST) were prepared and the interactions quantified by a colorimetric assay for GST activity determination. The presence of D2L-CPL3 fragment-Gia1 complexes was detected by SDS-polyacrylamide gel electrophoresis (PAGE). Kd values for the interaction of the three fragments with Gia1 were similar and in nmol/L range of concentrations, while the peptide representing the insert in the long form of the dopamine D2 receptor expressed about 10-fold lower binding affinity. These results could serve to design new therapeutic agents that might act at the level of receptor/G protein interaction rather than at the level of ligand-receptor binding.U cilju pronalaženja bitnih strukturnih motiva potrebnih za interakciju sa a podjedinicom Gi1 proteina klonirana su, eksprimirana i prečišćena 4 fragmenta treće citoplazmatične petlje (CPL3) dopaminskog D2L receptora koji su dalje pripremljeni kao fuzioni proteini sa glutation-S-transferazom (GST). Interakcije su kvantifikovane bojenom reakcijom za određivanje aktivnosti GST. Postojanje kompleksa D2L-CPL3 fragment- Gia1 je dokazano elektroforetskom analizom na SDS-poliakrilamidnom gelu (PAGE). Kd vrednosti za tri fragmenta su bile vrlo slične i u nmol/L opsegu koncentracija, dok je peptid koji predstavlja insert u dugom obliku dopaminskog D2 receptora posedovao oko 10 puta manji afinitet vezivanja za Gia1. Ovi rezultati mogu biti osnova za sintezu novih terapeutskih agenasa koji bi delovali na nivou interakcije receptora i G proteina umesto na nivou vezivanja liganda za receptor