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21.
Synthesis of 2‐(Quinoxalin‐2‐ylamino‐benzotriazolyl) Pentanedioic Derivatives as Potential Anti‐Folate Agents
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I. Briguglio S. Piras P. Corona M. A. Pirisi L. Burrai G. Boatto E. Gavini G. Rassu 《Journal of heterocyclic chemistry》2016,53(6):1721-1737
Anti‐folate agents had a significant impact on therapeutic treatment plans for diseases such as cancer, and bacterial and parasitic infections, notably malaria. Quinoxaline derivatives showed in vitro anticancer activity and were able to inhibit both the dihydrofolate reductase and thymidylate synthase. Here, we decided to combine the chemical properties of quinoxalines and quinoxaline 1,4‐dioxides with those of benzotriazole nucleus with the aim to evaluate the resulting biological properties. Two main new series, including more than 60 compounds, were prepared. In the first one, the benzotriazole moiety was linked through the nitrogen atoms 1, 2, or 3, to a glutaric acid substituent to simulate a glutamic moiety. In the second series, the glutaric acid was substituted with acetic acid moiety to evaluate the effects of steric hindrance. Here, we describe the multistep chemical processes to obtain all titled quinoxalines starting from commercially available diamines. The classical oxidation of selected quinoxalines was unsuccessful, and we have come to an independent synthetic pathway to obtain new derivatives linked to the benzotriazole moieties starting from synthons bearing N‐oxide functionality. 相似文献
22.
Maria Teresa Cocco Cenzo Congiu Valentina Onnis Angela Maria Bernard Pier Paolo Piras 《Journal of heterocyclic chemistry》1997,34(4):1283-1290
The reaction between N1-acylacetamidrazones 1 and enol ether 2 is described. Depending on the reaction conditions and on the substitution pattern of amidrazones 2-acylhydrazino-4-methyl-6-trifluoro-methylpyridines 3 and/or 2-acylhydrazino-6-methyl-4-trifluoromethylpyridines 4 were obtained. 相似文献
23.
Halide ions increase the rate of decarbalkoxylation of arylmethylene-propanedioic acids dimethyl esters. 相似文献
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25.
Angela M BernardAngelo Frongia Francesco SecciGiovanna Delogu Jean OllivierPier P Piras Jacques Salaün 《Tetrahedron》2003,59(47):9433-9440
Mixtures of (E and Z)-2-cyclobutylidenepropyl sulfonates, readily available from α,α-disubstituted cyclobutanones arising from suitable cyclopropane derivatives ring expansion, underwent regioselective and stereospecific reduction by formate anion to offer, through π-1,1-trimethyleneallylpalladium complexes formed upon treatment with palladium(0), a new and convenient entry to the diastereomeric four-membered ring monoterpenoids (±)-fragranol and (±)-grandisol. 相似文献
26.
Giovanni Calaresu Patrizia Piras Gavina Carta Roberta Galarini Giannina Chessa 《Accreditation and quality assurance》2006,11(1-2):10-16
A measurement uncertainty estimated for aflatoxin M1 determination in milk sample has been calculated using data generated from analytical method validation studies. The protocol
adopted is described in detail in document LGC/VAM/1998/088. The uncertainty budget was based on precision, trueness and ruggedness
data. The individual contributions are described in detail. The expanded uncertainty for aflatoxin M
1 at a concentration of 20 ng L−1 was estimated as 2.81 ng L−1. This was calculated using a coverage factor of two which gives a level of confidence of approximately 95%.
Presented at AOAC Europe / Eurachem Symposium March 2005, Brussels, Belgium 相似文献
27.
28.
Sandra Piras Mario Loriga Antonio Carta Giuseppe Paglietti M. Paola Costi Stefania Ferrari 《Journal of heterocyclic chemistry》2006,43(3):541-548
29.
Irene Piras Ralf Jackstell Anke Spannenberg Klaus-Diether Wiese 《Journal of organometallic chemistry》2010,695(4):479-3057
New modular H8-BINOL-based phosphite ligands have been synthesized. High activity and regioselectivity has been achieved in the rhodium-catalyzed isomerization-hydroformylation of internal olefins. The active catalysts have been characterized by insitu NMR studies. 相似文献
30.
Marzouki H Khaldi A Falconieri D Piras A Marongiu B Molicotti P Zanetti S 《Natural product communications》2010,5(12):1955-1958
The essential oils and supercritical CO2 extracts of wild Daucus carota L. subsp. carota from two different sites in Tunisia were investigated. The main components of the essential oil of the flowering and mature umbels with seeds from Sejnane were eudesm-7(11)-en-4-ol (8.2 - 8.5%), carotol (3.5 - 5.2%), sabinene (12.0 -14.5%), a-selinene (7.4 - 8.6) and 11-alpha-(H)-himachal-4-en-1-beta-ol (12.7 - 17.4%), whereas the oils from Tunis were predominantly composed of elemicin (31.5 - 35.3%) and carotol (48.0 - 55.7%). The antimicrobial activity of the essential oils were assayed by using the broth dilution method on Escherichia coli ATCC 35218 and Staphylococcus aureus ATCC 43300, and clinical strains of Candida albicans and C. tropicalis 1011 RM. The MIC values obtained were all > 2.5% (v/v). 相似文献