2990-03-6Relevant academic research and scientific papers
Enzyme-Inspired Lysine-Modified Carbon Quantum Dots Performing Carbonylation Using Urea and a Cascade Reaction for Synthesizing 2-Benzoxazolinone
Hasani, Morteza,Kalhor, Hamid R.
, p. 10778 - 10788 (2021/09/08)
Catalysts as the dynamo of chemical reactions along with solvents play paramount roles in organic transformations in long-lasting modes. Thus, developing effective and biobased catalysts in nontoxic solvents is highly in demand. In this report, carbon quantum dots (CQDs) functionalized with-lysine (Lys-CQDs) were generated from entirely nature-derived materials; they were demonstrated to be a promising catalyst for C-N bond formation in choline chloride urea (ChCl/U), a natural deep eutectic solvent (NADES). Among a number of synthesized CQDs, Lys-CQD turned out to be a powerful catalyst in the model reaction with aniline to afford phenyl urea. This type of transformation is important because aniline as a nucleophile has low activity, and urea is a very weak electrophile but an abundant natural source of the carbonyl moiety at the same time. The optimized reaction was performed under a highly desirable condition without using tedious and toxic workup processes at a low temperature (37 °C for aliphatic amines and 60 °C for aniline derivatives), as well as by embracing the broad scope of products in good to high yields even with weak nucleophiles such as aniline. A proposed acid-activated mechanism was suggested for the model reaction that was further confirmed by detecting ammonia as the leaving group. To show further multifunctionality of the catalyst, a cascade catalysis approach was developed for synthesizing 2-benzoxazolinone, which was furnished in a two-step transformation, starting from 2-aminophenol. Using X-ray crystallography, the structure of the final product in the cascade reaction was also determined. The catalyst was characterized using various analytical techniques including SEM, TEM, AFM, XRD, IR spectroscopy, UV-vis spectroscopy, DLS, and fluorescence spectroscopy. Measuring the acid/base sites by back titration, the catalyst was shown to be highly functionalized by the lysine functional group. The size of the catalyst was determined to be in the range of 1-8 nm, having a well-dispersed surface. In all, Lys-modified CQD, as a metal-free catalyst, was synthesized, characterized, and optimized for carbonylation, as well as a cascade reaction, under mild conditions. The whole process including catalyst synthesis and organic transformations is economically competitive and fulfills all requirements toward viability.
Synthesis, cytotoxic evaluation, and molecular docking studies of new oxadiazole analogues
Ahsan, Mohamed Jawed,Yadav, Raghunath Prasad,Saini, Saroj,Hassan, Mohd. Zaheen,Bakht, Mohammed Afroz,Jadav, Surender Singh,Al-Tamimi, Abdulmalik Bin Saleh,Geesi, Mohammed H.,Ansari, Md Yousuf,Khalilullah, Habibullah,Riadi, Yassine
supporting information, p. 49 - 56 (2018/03/06)
Background: Cancer is one of the major health diseases worldwide with an approximately 14 million new cases of cancer and 8.2 million cancer related death tolls were reported in 2012. The major complications associated with chemotherapy are limited effica
Discovery of novel 6,7-disubstituted-4-phenoxyquinoline derivatives bearing 5-(aminomethylene)pyrimidine-2,4,6-trione moiety as c-Met kinase inhibitors
Tang, Qidong,Zhang, Guogang,Du, Xinming,Zhu, Wufu,Li, Ruijuan,Lin, Huafang,Li, Pengcheng,Cheng, Maosheng,Gong, Ping,Zhao, Yanfang
, p. 1236 - 1249 (2014/03/21)
A series of novel quinoline derivatives bearing 5-(aminomethylene) pyrimidine-2,4,6-trione moiety were designed, synthesized, and evaluated for their c-Met kinase inhibitory activities and antiproliferative activities against 5 cancer cell lines (HT-29, H460, MKN-45, A549, and U87MG) in vitro. Most compounds showed moderate to excellent potency, with the most promising analogue 45 (c-Met half-maximal inhibitory concentration [IC50] = 1.15 nM) showing high selectivity versus 5 other tyrosine kinases, VEGFR-2, Flt-3, PDGFR-β, c-Kit, and EGFR. Structure-activity relationship studies indicated that electron-donating groups on the phenyl ring at the 3-position of pyrimidine-2,4,6-trione were required to increase the electron density on the 5-(aminomethylene)pyrimidine-2,4,6-trione moiety.
Imidazole incorporated semicarbazone derivatives as a new class of anticonvulsants: Design, synthesis and in-vivo screening
Amir, Mohammad,Ali, Israr,Hassan, Mohd. Zaheen
, p. 571 - 580 (2013/07/28)
A series of novel imidazole incorporated semicarbazones was synthesized using an appropriate synthetic route and characterized by spectral analysis (IR, 1H NMR, 13C NMR and Mass). The anticonvulsant activity of the synthesized compounds was determined using doses of 30, 100, and 300 mg kg-1 against maximal electroshock seizure (MES), subcutaneous pentylenetetrazole (scPTZ) induced seizure and minimal neurotoxicity test. Six compounds exhibited protection in both models and 2-(1-(4-chlorophenyl)-2-(1H-imidazol-1-yl)ethylidene)-N-p- tolylsemicarbazone emerged as the most active compound of the series without any neurotoxicity and significant CNS depressant effect. Liver enzyme estimations (SGOT, SGPT, Alkaline phosphatase) of the compound also showed no significant change in the enzymes levels. Moreover, it caused 80% elevation of γ-amino butyric acid (GABA) levels in the whole mice brain, thus indicating that it could be a promising candidate in designing of a potent anticonvulsant drug.
A NOVEL ACID-CATALYSED REARRANGEMENT OF N-ARYL-N'-ARYLOXYUREAS TO BIPHENYL DERIVATIVES. A -REARRANGEMENT INVOLVING THREE HETEROATOMS.
Endo, Yasuyuki,Terashima, Tohru,Shudo, Koichi
, p. 5537 - 5540 (2007/10/02)
In the presence of trifluoroacetic acid, N-phenyl-N'-phenoxyurea (1a) rearranges to N-(4'-hydroxy-2-biphenylyl)urea (2a) and N-carbamoyl-2-hydroxy-diphenylamine (3a).The rearrangement is an intramolecular reaction, and the transition state of the breakage of the N-O bond is deduced to be polarized in the form Nδ+(*)Oδ+.
