scholarly journals New sesquiterpene hydroquinones from the Caribbean sponge Aka coralliphagum

2014 ◽  
Vol 10 ◽  
pp. 613-621 ◽  
Author(s):  
Qun Göthel ◽  
Matthias Köck

Four new sulfated sesquiterpene hydroquinones siphonodictyals E1–E4 (1–4) and cyclosiphonodictyol A (5) were isolated from a sample of the Caribbean sponge Aka coralliphagum collected off the coast of San Salvador in the Bahamas. The structures of the new compounds were elucidated on the basis of mass spectrometric and NMR spectroscopic analysis. Compounds 1–4 are derivatives of siphonodictyal E (9). Siphonodictyal E4 (4) exhibited mild antiproliferation activity against L929 mouse fibroblast, KB-31 epidermoid carcinoma, and MCF-7 breast cancer cell lines, while siphondictyal E3 (3) and cyclosiphonodictyol A (5) showed moderate activity against Gram-positive bacteria.

2007 ◽  
Vol 4 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Baghdad Science Journal

Five derivatives of thiadiazole were prepared with aldehydes and alkyl halides, compoundA: 2-amino-5-thiol-1,3,4- thiadiazole, compound B :2-(o-hydroxybenzylidine)amino-5-thiol-1,3,4-thiadiazole, compoundC: 2(2-butan-lidine)amino-5-thiol-1,3,4-thiadiazole, compound E: 2- amino-5-(2-Propanylthio)-1,3,4-thiadiazol) and compound F:2(o-chlorobenzylamino)-5-(2-propanyl thio)-1,3,4 thiadiazol. All prepared compounds were diagnosed by (IR) and (UV) Spectroscopy. All of those compounds were screened for their anti-microbial activity in vitro. The results show that most of the compounds A, B, C exhibited moderate to good activity against Gram-positive bacteria and the same compound exhibit low to moderate activity on most gram-negative bacteria under study. Finally, compound E and F had little or no effect organism.


2021 ◽  
Vol 22 (11) ◽  
pp. 5626
Author(s):  
Tam Minh Le ◽  
Thu Huynh ◽  
Fatima Zahra Bamou ◽  
András Szekeres ◽  
Ferenc Fülöp ◽  
...  

Discovery of novel antibacterial agents with new structures, which combat pathogens is an urgent task. In this study, a new library of (+)-neoisopulegol-based O-benzyl derivatives of aminodiols and aminotriols was designed and synthesized, and their antimicrobial activity against different bacterial and fungal strains were evaluated. The results showed that this new series of synthetic O-benzyl compounds exhibit potent antimicrobial activity. Di-O-benzyl derivatives showed high activity against Gram-positive bacteria and fungi, but moderate activity against Gram-negative bacteria. Therefore, these compounds may serve a good basis for antibacterial and antifungal drug discovery. Structure–activity relationships were also studied from the aspects of stereochemistry of the O-benzyl group on cyclohexane ring and the substituent effects on the ring system.


Author(s):  
A. M. Zaed, , M. Khlifa

This work describes the synthesis of novel nonracemic derivatives of imidazole. Some oxidation reactions using Mn(II), Se(II) and nitric acid were employed for the synthesis of the starting materials, imidazolyl carboxaldehydes in straightforward steps. These key step compounds were then subjected to schiff bases and reductive amination processes for the synthesis imidazolylimio and imidazolylamino compounds using standard conditions. Attempts to purify some imidazolylamino compounds using kugelrohr distillation technique have been unsuccessful. However, recrystallization from acetonitrile allowed isolation some compounds in good yields. The new compounds that were synthesised were potential ligands for complexation of metals. Ag(I) was used to synthesis of several metal complexes. These compounds were characterised by nuclear magnetic resonance (NMR) and fourier transform infrared spectroscopy (FTIR) as well as elemental analysis method. These imidazole derivatives have been screened for activity against Candida albicans. Although the S-enantiomer of N-[(1E)-1-benzyl imidazol-2-ylmethylene]-N′-(1-phenylethyl)amine was found inactive against C. albicans, the R-enantiomer showed moderate activity. However, in two instances the activity was greater than that for ketoconazole which is a common agent to cure candida infestation.


2020 ◽  
Vol 5 (443) ◽  
pp. 85-91
Author(s):  
Ibrayev M.K., ◽  
◽  
Takibayeva A.T., ◽  
Fazylov S.D., ◽  
Rakhimberlinova Zh.B., ◽  
...  

This article presents studies on the targeted search for new derivatives of azoles, such as benzthiazole, 3,5-dimethylpyrazole, 1,3,4-oxadiazole-2-thione, 1,3,4-thiadiazole. The possibility of combining in one molecule of the azole ring with other cyclic compounds: the alkaloid cytisine, morpholine, furan and some arenes has been studied. To obtain new compounds, the reactions of bromination, acylation, and interaction with isothiocyanates were studied. Optimal synthesis conditions were studied for all reactions. It was found that the reaction of 4-bromo-3,5-dimethylpyrazole with isothiocyanates, in contrast to the previously written derivatives of anilines, takes a longer time and requires heating the reaction mixture. The combination of a pirasol fragment with halide substituents often results in an enhanced therapeutic effect. The synthesized 2-bromine-N-(6-rodanbenzo[d]thiazole-2-yl)acetamide, due to the alkylbromide group, is an important synth in the synthesis of new benzthiazole derivatives. Its derivatives combine in one molecule the rest of rhodanbenzthiazole with alkaloid cytisine and biogenic amine morpholine and are potentially biologically active compounds, since the molecule structure contains several pharmacophoric fragments: benzthiazole and alkaloid (amine) heterocycles, rhodane and urea groups. The mechanism of formation of 1,3,4-oxadiazole-2-tyons from hydrazides under action on them by carbon disulfide was studied and assumed. It was shown that dithiocarbamates in acidic medium decompose with the release of hydrogen sulfide and the formation of highly reactive isothiocyanate group. Then, intra-molecular cyclization occurs, with the formation of end products - 1,3,4-oxadiazole-2-thions. The structures of the synthesized compounds were studied by 1H and 13C NMR spectroscopy. All synthesized substances are potentially biologically active compounds, since they contain several pharmacophore fragments in their structure.


2020 ◽  
Vol 17 ◽  
Author(s):  
Rahele Bargebid ◽  
Ali Khalafi-Nezhad ◽  
Kamiar Zomorodian ◽  
Leila Zamani ◽  
Ali Ahmadinejad ◽  
...  

Introduction: Mannich reaction is a typical example of a three-component condensation reaction and the chemistry of Mannich bases has been the matter of search by researchers. Here an efficient procedure for the synthesis of some new Mannich derivatives of simple phenols is described. Methods: In this procedure a microwave-assisted and solvent less condensation were done between different phenols, secondary amines and paraformaldehyde. The reactions proceed in the presence of catalytic amount of nano ZnO and tetrabutylammonium bromide (TBAB) in excellent yields. 10 new compounds were synthesized (A1-A10). Chemical structures of all new compounds were confirmed by different spectroscopic methods. We optimized the chemical reactions in different conditions. Optimization reactions were done in the presence of different mineral oxides, different amount of TBAB and also different solvents. Nano ZnO and TBAB in catalytic amounts and solvent free conditions were the best conditions. All the synthesized compounds were screened for their antimicrobial activities. Antifungal and antibacterial activities of the synthesized compounds were evaluated against some Candida, filaments fungi, gram positive and gram negative bacteria by broth micro dilution method as recommended by CLSI. Results: The result showed that compounds A2, A3 and A4 against most of the tested Candida species and compounds A5 and A7 against C. parapsilosis and C. tropicalis, exhibited considerable antifungal activities. Also Compounds A8 and A10 showed desirable antifungal activities against C. neoformance and C. parapsilosis, respectively. The antibacterial activities of the synthesized compounds were also evaluated. Compounds A6 - A10 against E. Fecalis and compounds A5, A7, A9 and A10 against P. aeruginosa showed desirable antibacterial activities. Discussion: We have synthesized some new Mannich adducts of poly-hydroxyl phenols in the presence of nano-ZnO as a reusable catalyst, with the hope of discovering new lead compounds serving as potent antimicrobial agents. The advantages of this method are generality, high yields with short reaction times, simplicity, low cost and matching with green chemistry protocols. The antimicriobial studies of Mannich derivatives of phenols showed desirable results in vitro.


Author(s):  
Devidas G. Anuse ◽  
Suraj N. Mali ◽  
Bapu R. Thorat ◽  
Ramesh S. Yamgar ◽  
Hemchandra K. Chaudhari

Background: Antimicrobial resistance is major global health problem, which is being rapidly deteriorating the quality of human health. Series of substituted N-(benzo[d]thiazol-2-yl)-2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)acetamide (3a-j) were synthesized from substituted N-(benzo[d]thiazol-2-yl)-2-chloroacetamide/bromopropanamide (2a-j) and 6-fluoro-3-(piperidin-4-yl)benzo[d]isoxazole (2) and further evaluated for their docking properties and antimicrobial activity. Methods: All synthesized compounds were characterized by FT-IR, NMR and Mass spectral analysis. All compounds were allowed to dock against different antimicrobial targets having PDB ID: 1D7U and against common antifungal target having PDB ID: 1EA1. Results: The compounds 3d and 3h were showed good activity against Methicillin-resistant Staphylococcus aureus (MRSA, resistance Gram-positive bacteria). All synthesized compounds showed good to moderate activity against selected bacterial and fungal microbial strains. If we compared the actual in-vitro antimicrobial activity and in-silico molecular docking study, we found that molecules 3i and 3h were more potent than the others. Conclusion: Our current study would definitely pave the new way towards designing and synthesis of more potent 2-aminobenzothiazoles derivatives.


2017 ◽  
Author(s):  
Karen A. Kopcznski ◽  
◽  
Ilya V. Buynevich ◽  
H. Allen Curran ◽  
Christopher A. Sparacio ◽  
...  

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