Showing papers by "Wafaa S. Hamama published in 2012"
TL;DR: In this paper, 3-Acetylcoumarin was utilized as a key intermediate for the synthesis of 2-aminothiazole derivative 3 via bromination of 1 followed by treatment of the formed acetylbromide 2 with thiourea or via Bignailli reaction of 1. Representative compounds of the synthesized products were evaluated as antitumor and antioxidant agents.
Abstract: 3-Acetylcoumarin (1) was utilized as a key intermediate for the synthesis of 2-aminothiazole derivative 3
via bromination of 1 followed by treatment of the formed acetylbromide 2 with thiourea or via Bignailli reaction of 1. Treatment of 3 with 2 afforded the bis-coumarin 4, whereas, cyanoacetylation of 3 followed by treatment of the formed cyanoacetamide 6 with salicyaldehyde give the bis-coumarin 7. Reaction of 6 with phenyl isothiocyanate in DMF/KOH produced the potassium salt 8, which cyclized with chloroacetyl chloride to give the thiazolidinone 9. Acidification of 8 with HCl afforded the thiocarbamoyl 10, which condensed with 2 in DMF to give the mercapto derivative 12, whereas in DMF/TEA gave the thiophene derivative 13. The thiophenes 15a–c were achieved via treatment of the thiocarbamoyls 14a–c with 2 in DMF/TEA, whereas, in DMF gave the corresponding thiazoles 16a–c. Treatment of the components 17a, b with carbon disulfide in DMF/KOH followed by addition of 2 afforded the dithioacetals 19a, b. Cyclization of 19b under alkaline condition gave the desired thiophene 20. Representative compounds of the synthesized products were evaluated as antitumor and antioxidant agents. 3-Acetylcoumarin (1) was utilized as a key intermediate for the synthesis of different coumarin derivatives. Newly synthesized compounds were elucidated by analytical and spectral data. Representative compounds of the synthesized products were evaluated as antitumor and antioxidant agents.
59 citations
39 citations
TL;DR: In this article, the synthesis and biological properties of some novel isolated or fused heterocyclic ring systems with pyrazole were described, including enaminones containing pyrazolone ring photochromic functional unit, 4-[(4-chlorophenylamino)methylene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (3) and some analogous derivatives 4, 9, and 10, also as pyrazolo[3, 4-b]pyridine, pyrazoline, py
23 citations
TL;DR: Heterocyclic annulation of the isoxazolo[5,4‐b]pyridine system was achieved via reaction of 1 with benzylidene derivatives of indandione, quinuclidone, pyrazolone, and oxazolone.
Abstract: The reaction of 5-amino-3-methylisoxazole with appropriate α,β-unsaturated ketones gave the corresponding isoxazolo[5,4-b]pyridines. Treatment of 1 with 2,6-dibenzylidenecyclohexanone or 2-benzylidenedimedone afforded the corresponding isoxazolo[5,4-b]quinoline derivatives. 4,6,8,9-Tetrahydroisoxazolo[5,4-b]quinolin-5-one derivative was also obtained by multicomponent condensation reaction of 1 with dimedone and benzaldehyde. Heterocyclic annulation of the isoxazolo[5,4-b]pyridine system was achieved via reaction of 1 with benzylidene derivatives of indandione, quinuclidone, pyrazolone, and oxazolone. A representative of some newly synthesized compounds was evaluated as antitumor agents.
23 citations
TL;DR: In this paper, the Mannich reaction was used for the synthesis of several new thiazolo[3,2-a][1,3,5]triazine derivatives.
Abstract: 2-Iminothiazolidin-4-one (1) was utilized for the synthesis of several new thiazolo[3,2-a][1,3,5]triazine derivatives. 3-Phenyl-3,4-dihydro-2H-thiazolo[3,2-a][1,3,5]triazin-6(7H)-one (2) was prepared according to Mannich procedure. Both compounds 1 and 2 reacted with aromatic aldehydes to afford arylidene derivatives 3–7. Compounds 5–7 were obtained through another two routes of preparation, first when applying Mannich reaction to compounds 3 and 4 and second by reacting compounds 2 with activated olefins 11 catalyzed by triethylamine, also, the reaction of 2 with bis arylidene 16 afforded compound 18. Compound 2 reacted with both mono and di-aromatic diazonium salts to furnish 2-aryl-azothiazolo[3,2-a]triazines 20 and 21 or bis[2-azothiazolo[3,2-a]triazine]phenylene 22, respectively. Thiocarbamoyl derivatives 25 and 26 were prepared through the reaction of active methylene and imino group in 1 with phenylisothiocyanate and carbon disulfide, respectively. Structures confirmation, geometry, and biological evaluation were applied for the newly prepared compounds.
17 citations
TL;DR: In this paper, 2H-Thiazolo[3,2-a]pyrimidine-3,5,7(6H)-trione was synthesized and characterized via molecular quantum parameters using the PM3-semi-empirical MO method.
4 citations
09 May 2012
TL;DR: In this paper, the synthesis of macrocyclic systems incorporating either fused or exocyclic nitrogen heterocycles of differ- ent ring sizes was investigated, and ring enlargement was also implemented.
Abstract: Ethyl 2-oxocyclododecanecarboxylate (1), and 2-(hydroxyl-methylene)cyclododecanone (7) were used as key intermediates for synthesis of macrocyclic systems incorporating either fused or exocyclic nitrogen heterocycles of differ- ent ring sizes. Ring enlargement was also implemented.
4 citations
TL;DR: From the synthesized new title compounds the coumarins (VII, (XII), and (XVI) exhibit a high antioxidant activity in comparison to ascorbic acid as mentioned in this paper.
Abstract: From the synthesized new title compounds the coumarins (VII), (XII), and (XVI) exhibit a high antioxidant activity in comparison to ascorbic acid.
TL;DR: In this article, the title compound (I) is annulated to suitable electrophiles via cyclocondensation reactions, with a view to obtaining biologically active derivatives, and the corresponding derivatives are obtained via the same process.
Abstract: With a view to obtaining biologically active derivatives the title compound (I) is annulated to suitable electrophiles via cyclocondensation reactions.
TL;DR: In this paper, 14 novel compounds incorporating pyrazolone or pyrazole moieties were synthesized and characterized, including quantum mechanical molecular orbital calculations, and fourteen novel compounds were characterized.
Abstract: Fourteen novel compounds incorporating pyrazolone or pyrazole moieties are synthesized and characterized, including quantum mechanical molecular orbital calculations.
TL;DR: A comprehensive review of cyclododecanone chemistry over the period from 1950 to 2010 is presented in this article, which covers the different aspects of cyclodecane chemistry over time.
Abstract: Cyclododecanone is a highly important synthetic intermediate for macrocyclic systems. This review is the sole and comprehensive one that covers the different aspects of cyclododecanone chemistry over the period from 1950 to 2010.
TL;DR: A variety of isoxazolopyridine derivatives and related compounds are synthesized starting from 5-amino-3-methylisoxazole (I) as mentioned in this paper.
Abstract: A variety of isoxazolopyridine derivatives and related compounds are synthesized starting from 5-amino-3-methylisoxazole (I).