Discovery of gargantulides B and C, new 52-membered macrolactones from Amycolatopsis sp. Complete absolute stereochemistry of the gargantulide family

Author(s):  
Daniel Carretero-Molina ◽  
Francisco Javier Ortiz-López ◽  
Tetiana Gren ◽  
Daniel Oves-Costales ◽  
Jesús Martín ◽  
...  

Gargantulides B and C, two new and highly complex 52-membered glycosylated macrolactones, were isolated from Amycolatopsis sp. strain CA-230715 during an antibacterial screening campaign. The structures of these giant macrolides...

2020 ◽  
Vol 17 ◽  
Author(s):  
Ravi Bansal ◽  
Pradeep K. Soni ◽  
Neha Gupta ◽  
Sameer S. Bhagyawant ◽  
Anand K. Halve

Aims: In this article we have developed an eco-friendly one-pot multi-component reaction methodology was employed for the green synthesis of functionalized pyrazole derivatives viz cyclo-condensation of aromatic aldehydes, ethyl acetoacetate and phenyl hydrazine and/or hydrazine hydrate in the presence of cetyltrimethylammoniumbromide (CTAB) at 90°C temperature in aqueous medium. Method: In the present protocol we developed a green method for the synthesis of functionalized pyrazole derivatives through one-pot, multi-component cyclo-condensation of aromatic aldehydes, phenyl hydrazine or hydrazine hydrate and ethyl acetoacetate using cetyltrimethylammoniumbromide (CTAB) as a catalyst in water as solvent. Our methodology confers advantages such as short reaction time, atom economy, purification of product without using column chromatographic and hazardous solvent. The reaction is being catalyzed by cetyltrimethylammoniumbromide (CTAB) and thus products are formed under the green reaction conditions. Results: Initially the reaction of benzaldehyde and phenylhydrazine with ethyl acetoacetate was carried out in water at room temperature in the absence of the catalyst; no product was obtained after 24 h (Table 1 entry 1). When the reaction was carried out using L-proline as catalyst in ethanol at 70°C the yield of product was 20. Conclusion: This research not only provides a green and efficient method for the synthesis of sulfinic esters but also shows new applications of electrochemistry in organic synthesis. We consider that this green and efficient synthetic protocol used to prepare sulfinic esters will have good applications in future. In conclusion, we have developed successfully a green and efficient one-pot multi-component methodology for the synthesis of substituted pyrazoles using CTAB as a catalyst in water as solvent with excellent yields. Purifications of compounds were achieved without the use of traditional chromatographic procedures. This methodology has advantages of operational simplicity, clean reaction profiles and relatively broad scope which make it more attractive for the diversity oriented synthesis of these heterocyclic libraries. In this methodology we suggest the further alternative possibility for formation of substituted pyrazoles. The compound 7h can be used as an anticancer drug in pharma industry.


2019 ◽  
Vol 16 (3) ◽  
pp. 245-248
Author(s):  
Hummera Rafique ◽  
Aamer Saeed ◽  
Ehsan Ullah Mughal ◽  
Muhammad Naveed Zafar ◽  
Amara Mumtaz ◽  
...  

Background: (±)-6,8-Dihydroxy-3-undecyl-3,4-dihydroisochromen-1-one is one of the structural analog of several substituted undecylisocoumarins isolated from Ononis natrix (Fabaceae), has been successfully synthesized by direct condensation of homopthalic acid (1) with undecanoyl chloride yields isochromen-1-one (2). Methods: Alkaline hydrolysis of (2) gave the corresponding keto-acid (3), which is then reduced to hydroxy acid (4) then its cyclodehydration was carried out with acetic anhydride to afford 3,4- dihydroisochromen-1-one (5). Followed by demethylation step, the synthesis of target 6,8- dihydroxy-7-methyl-3-undecyl-3,4-dihydroisocoumarin (6) was achieved. Results: In vitro antibacterial screening of all the synthesized compounds were carried out against ten bacterial strains by agar well diffusion method. Conclusion: Newly synthesized molecules exhibited moderate antibacterial activity and maximum inhibition was observed against Bacillus subtilus and Salmonella paratyphi.


2019 ◽  
Vol 15 (5) ◽  
pp. 445-455 ◽  
Author(s):  
Suraj N. Mali ◽  
Sudhir Sawant ◽  
Hemchandra K. Chaudhari ◽  
Mustapha C. Mandewale

Background: : Thiadiazole not only acts as “hydrogen binding domain” and “two-electron donor system” but also as constrained pharmacophore. Methods:: The maleate salt of 2-((2-hydroxy-3-((4-morpholino-1, 2,5-thiadiazol-3-yl) oxy) propyl) amino)- 2-methylpropan-1-ol (TML-Hydroxy)(4) has been synthesized. This methodology involves preparation of 4-morpholino-1, 2,5-thiadiazol-3-ol by hydroxylation of 4-(4-chloro-1, 2,5-thiadiazol-3-yl) morpholine followed by condensation with 2-(chloromethyl) oxirane to afford 4-(4-(oxiran-2-ylmethoxy)-1,2,5-thiadiazol- 3-yl) morpholine. Oxirane ring of this compound was opened by treating with 2-amino-2-methyl propan-1- ol to afford the target compound TML-Hydroxy. Structures of the synthesized compounds have been elucidated by NMR, MASS, FTIR spectroscopy. Results: : The DSC study clearly showed that the compound 4-maleate salt is crystalline in nature. In vitro antibacterial inhibition and little potential for DNA cleavage of the compound 4 were explored. We extended our study to explore the inhibition mechanism by conducting molecular docking, ADMET and molecular dynamics analysis by using Schrödinger. The molecular docking for compound 4 showed better interactions with target 3IVX with docking score of -8.508 kcal/mol with respect to standard ciprofloxacin (docking score= -3.879 kcal/mol). TML-Hydroxy was obtained in silico as non-carcinogenic and non-AMES toxic with good percent human oral absorption profile (69.639%). TML-Hydroxy showed the moderate inhibition against Mycobacteria tuberculosis with MIC 25.00 μg/mL as well as moderate inhibition against S. aureus, Bacillus sps, K. Pneumoniae and E. coli species. Conclusion: : In view of the importance of the 1,2,5-thiadiazole moiety involved, this study would pave the way for future development of more effective analogs for applications in medicinal field.


2020 ◽  
Vol 20 (4) ◽  
pp. 448-454
Author(s):  
Rahmita Burhamzah ◽  
Gemini Alam ◽  
Herlina Rante

Background: Endophytic fungi live in plants’ tissue and can produce the same bioactive compounds as its host plant produces. Syzygiumpolyanthum leaves have known to be one of the antibacterial compound producers. Aim and Objective: This study aimed to characterize morphologically, microscopically, and molecularly the antibacterial-producing endophytic fungi of Syzygiumpolyanthum leaves. Methods: The isolation of endophytic fungi was done by fragment planting method on PDA medium. The antibacterial screening was performed using the antagonistic test as the first screening followed by the disc diffusion test method. The morphological characterization was based on isolate’s mycelia color, growth pattern, margin, and surface texture of the colony, while the microscopic characterization was based on its hyphae characteristics. The molecular characterization of the isolate was done by nitrogen base sequence analysis method on nucleotide constituent of ITS rDNA genes of the isolate. Results: The results found that isolate DF1 has antibacterial activity against E.coli, S.aureus, P.acne, and P.aeruginosa, with the greatest inhibition at 10% concentration of broth fermentation extract on S.aureus with a diameter of inhibition of 13.77 mm. Conclusion: Based on macroscopic, microscopic, and molecular characterization, DF1 isolate is similar to Ceriporialacerate.


1996 ◽  
Vol 61 (11) ◽  
pp. 1681-1688 ◽  
Author(s):  
Michal Bodajla ◽  
Štefan Stankovský ◽  
Katarína Špirková ◽  
Soňa Jantová

Some 4-amino substituted 2-phenyl-6H-5,1,3-benzothiadiazocines (4a-4j) were prepared by cyclization of the corresponding N1-[N-(2-chloromethylphenyl)benzimidoyl]-N2-substituted thioureas (3a-3j). The IR,1H NMR and mass spectra of the title compounds are reported together with the results of antibacterial screening.


1992 ◽  
Vol 57 (7) ◽  
pp. 1459-1465 ◽  
Author(s):  
Nobuyuki Harada ◽  
Tatsuo Sugioka ◽  
Hisashi Uda ◽  
Takeo Kuriki

The 8aR absolute stereochemistry of Wieland-Miescher ketone (-)-I was established by the X-ray structure analysis of its bis(4-bromobenzoate) derivatives (1R,6R,8aR)-(+)-IV and (1R,6S,8aR)-(-)-V. The absolute configuration of (-)-I was corroborated further by the application of the CD exciton chirality method to bis(4-bromobenzoates) (+)-IV and (-)-V.


ChemInform ◽  
2010 ◽  
Vol 32 (34) ◽  
pp. no-no
Author(s):  
Takaaki Kubota ◽  
Masashi Tsuda ◽  
Jun'ichi Kobayashi

2021 ◽  
Vol 86 (5) ◽  
pp. 4281-4289
Author(s):  
Brian T. Chamberlain ◽  
Mathilde Vincent ◽  
Jordan Nafie ◽  
Peter Müller ◽  
Anna Greka ◽  
...  

ChemInform ◽  
2010 ◽  
Vol 33 (14) ◽  
pp. no-no
Author(s):  
Shoji Kobayashi ◽  
Shukuko Ashizawa ◽  
Yusuke Takahashi ◽  
Yukio Sugiura ◽  
Makoto Nagaoka ◽  
...  

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