- Polymorphism control in the mechanochemical and solution-based synthesis of a thermochromic Schiff base
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Three crystal forms of a thermochromic Schiff base, namely 1-{3-[(2-hydroxy-3-methoxy-benzylidene)-amino]-phenyl}-ethanone, derived from o-vanillin and 3-aminoacetophenone, were obtained by conventional solution-based methods. Two out of the three polymorphs were synthesized by mechanochemical syntheses, under solvent-free conditions. Herein, we report a study of the dependence of the composition of solvent, the crystallization temperature and impurities on the outcome of the synthesis of Schiff base polymorphs. We report the important role of seed crystals in directing the supramolecular organization of the product of a covalent solvent-free reaction towards the intended polymorphic outcome as well. All obtained polymorphs were investigated by means of thermal analysis, single crystal X-ray diffraction, ex situ and in situ powder X-ray diffraction and IR spectroscopy. The polymorphs display interesting and remarkably different molecular packing arrangements governed by C-H?O interactions leading to two-dimensional networks in forms I and III, and a three-dimensional networks in form II.
- Zba?nik, Marija,Nogalo, Ivana,Cin?i?, Dominik,Kaitner, Branko
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- Antiobesity, antioxidant and cytotoxicity activities of newly synthesized chalcone derivatives and their metal complexes Dedicated to Professor R. R. Schmidt on the occasion of his 79th birthday.
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Four sets of rationally designed chalcones were prepared for evaluation of their antiobesity, antioxidant and cytotoxicity activities. These sets include nine oleoyl chalcones as mimics of oleoyl estrone, three monohydroxy chalcones (chalcone ligands), Schiff base-derived chalcones and four copper as well as zinc complexes. Oleoyl chalcones 4d, 4e and particularly 6a as an isosteric isomer of oleoyl estrone, were as active as Orlistat on weight loss and related metabolic parameters using male SD rats in vivo. Chalcone ligands 10a-c and Schiff base-derived chalcones 11 and 14a,b were weakly antioxidants, while, the copper and zinc complexes 15a-d were good antioxidants with zinc chelates 15b,d being more active than their copper analogues 15a,cin vitro. Compounds 10c and 14a showed good cytotoxicity activities as Doxorubicin against PC3 cancer cell line in vitro, while, the copper complex 15c showed promising activity with IC50 value of 5.95 μM. The estimated IC50 value for Doxorubicin was 8.7 μM. Chalcones 14a,b are bifunctional probes for potential investigations in cancer diagnosis and radiotherapy by complexation with Gd3+ or metal radioisotopes followed by posttranslation of Shiga toxin B-subunits that target globotriosyl ceramide expressing cancer cells.
- El Sayed Aly, Mohamed Ramadan,Abd El Razek Fodah, Hamadah Hamadah,Saleh, Sherif Yousef
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p. 517 - 530
(2014/03/21)
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- Design, synthesis and in vitro antimalarial evaluation of new quinolinylhydrazone derivatives
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A series of novel quinolinylhydrazones (5a-f) was synthesized by the condensation reaction of 2,6-diaryl-substituted piperidin-4-ones (4a-f) with 7-chloro-4-hydrazinoquinoline (2). Novel quinolinylhydrazones containing Shiff bases 8a-f and 11a-f were obta
- Thuy, Le Thi,Tien, Hoang Xuan,Hoang, Vu Dinh,Vu, Tran Khac
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scheme or table
p. 163 - 168
(2012/07/17)
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- The synthesis and structure of l-[3-{(2-hydroxybenzylidene)amino}phenyl] ethanone
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Two Schiff base Iigands SACPNyH 1 and 5BrSACPNyH 2 are synthesized from the condensation reactions of salicylaldehyde and 5-bromosalicyIaldehyde respectively with 3-aminoaceto- phenone and characterized by elemental analyses, mass, electronic, infrared sp
- De Lai, Rajib,Mukhcrjee, Jaydcep,Mandal, Mahuya,Roy, Lovely,Bhowal, Ruchika,Banerjee, Indrajit
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experimental part
p. 595 - 598
(2009/12/24)
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- Solvent-free syntheses of salicylaldimines assisted by microwave irradiation
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A microwave-assisted condensation of salicylaldehyde and aryl amines without solvent were efficiently performed to form a series of salicylaldimines in high yields, which were confirmed by IR, 1H NMR, 13C NMR and elemental analyses. The microwave-assisted condensation provided a convenient environmental-friendship methodology for syntheses of Schiff-base in organic syntheses.
- Yang, Haijian,Sun, Wen-Hua,Li, Zilong,Wang, Leyong
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p. 2395 - 2402
(2007/10/03)
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- Mixed ligand complexes of cobalt(II and III) - Molecular structure of bis-(4-acetophenylsalicylaldiminato)acetylacetonato cobalt(III)
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The bidentate Schiff bases, HL′(= N-4-acetophenylsalicylal-dimine), H″(=N-3-acetophenylsalicylaldimine) and HL? (=N-4-acetophenyl-5-bromosalicylaldimine) do not form complexes with simple cobalt(II)salts, e.g.,Co(CH3COO)2.4H2/s
- De Lal,Banerjee,Mukherjee,Guha
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p. 1050 - 1054
(2007/10/03)
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- Exchange of amine part of schiff bases with ammonia in presence of a metal ion: Molecular structure of bis-(salicylaldiminato) nickel(II)
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The schiff bases N-X1-acetophenyl-X2-salicylaldimines (X1=4 or 3; *X2=H or 5Br) inert to complexation with nickel(II) and cobalt(II) salts undergo very prompt reactions when ammonia is added to the reaction mixt
- De, Rajib Lal,Banerjee, Indrajit,Samanta, Chitra,Mukherjee, Alok K.
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p. 373 - 376
(2007/10/03)
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