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p. 383-392
Received: 26 April 2006 / Accepted: 12 June 2006 / Published: 12 June 2006
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| Download PDF Full-text (70 KB) Abstract: A simple, efficient, and general method has been developed for the synthesis ofvarious 3-alkylquinazolin-4-one derivatives from quinazolin-4-one treated with alkylbromides under phase transfer catalysis condition. The structures of the compounds werecharacterized by elemental analysis, IR, 1 H-NMR and 13 C-NMR spectra. Title compound6-bromo-3-propylquinazolin-4-one (3h) was found to possess good antifungal activity.
p. 393-402
Received: 10 May 2006 / Accepted: 9 June 2006 / Published: 12 June 2006
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| Download PDF Full-text (127 KB) Abstract: A series of N,N’-disubstituted-2-nitroethene-1,1-diamine and N,N’-disubstituted- N’’-cyanoguanidine derivatives were prepared and evaluated for in vivo analgesic activity. The blood brain barrier (BBB) VolSurf model was used to predict the BBB permeation profiles of our synthesized compounds. Some compounds show both remarkable analgesic activity and good BBB permeation profiles, and these compounds might be developed for treatment of opioid tolerance and dependence.
p. 403-414
Received: 10 May 2006 / Accepted: 8 June 2006 / Published: 12 June 2006
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| Download PDF Full-text (87 KB) Abstract: The reaction of homophthalic anhydride and N-(furan-2-yl-methylidene)- benzylamine in different solvents and varying temperatures was studied in detail. Mixtures of the expected trans- and cis-1,2,3,4-tetrahydroisoquinoline-4-carboxylic acids trans-5 and cis-5, alongwith by-products 6 and 7 were obtained in dichloroethane or benzene. In pyridine, used for the first time, the reaction became completely diastereoselective, giving only the trans isomer. The carboxylic acid group of trans-5 was transformed in four steps into cyclic aminomethyl groups which yielded various new tetrahydroisoquinolinones trans- 11a-g, incorporating both a known fragment of pharmacological interest and various pharmacophoric substituents.
p. 415-420
Received: 7 June 2006 / Accepted: 9 June 2006 / Published: 12 June 2006
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| Download PDF Full-text (59 KB) Abstract: Computational studies on three tautomeric forms of four 1,5,6,7-tetrahydro- 4H-indazol-4-one derivatives: 1,5,6,7-tetrahydro-4H-indazol-4-one (1), 6,6-dimethyl- 1,5,6,7-tetrahydro-4H-indazol-4-one (2), 3-methyl-1,5,6,7-tetrahydro-4H-indazol-4-one (3) and 3,6,6-trimethyl-1,5,6,7-tetrahydro-4H-indazol-4-one (4), have been performed at different levels, ranging from semiempirical AM1, ab initio Hartree-Fock HF/6-31G* and HF/6-31G** to B3LYP/6-31G** density functional calculations. These calculations have been used to establish the most stable tautomer, which in all cases was in agreement with the experimental data.
p. 421-434
Received: 27 November 2005 / Accepted: 2 May 2006 / Published: 20 June 2006
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| Download PDF Full-text (104 KB) Abstract: Hypervalent iodine reagents constitute a powerful tool in modern synthetic organic chemistry, promoting several important reactions. One such reaction is the ring contraction of cycloalkenes and cycloalkanones promoted by iodine(III) compounds, such as iodobenzene diacetate, iodosylbenzene, iodotoluene difluoride, and [hydroxy(tosyloxy)- iodo]benzene (Koser ́s reagent). This review covers all the literature related to the ring contraction of cyclic ketones and olefins promoted by iodine(III) species.
p. 435-443
Received: 8 June 2006; in revised form: 13 June 2006 / Accepted: 15 June 2006 / Published: 21 June 2006
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| Download PDF Full-text (93 KB) Abstract: We report the asymmetric synthesis of di-3-pentyl (3S,αS,7E)-3-N-benzyl-N- α-methylbenzylamino-dec-7-enedioate (9), which contains the correct functionalization to produce δ-amino acid derivatives to be used as monomers for Peptide Nucleic Acid (PNA) formation With this aim, thymine-pentanoic acid 15 and some of its ester derivatives were obtained, their reactivity was studied and the noteworthy ethyl ester 12 was quantitatively produced by transesterification of methyl ester 11, thus paving the way for the synthesis of the thymine-containing amino ester IV, which has been designed as a building block for a Nucleic-Acid analog with a chiral, flexible peptide backbone
p. 444-452
Received: 31 May 2006; in revised form: 17 June 2006 / Accepted: 19 June 2006 / Published: 22 June 2006
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| Download PDF Full-text (259 KB) Abstract: 1-Allyl- (2) and 7-allyl-6-amino-3-methyl-1,2,4-triazolo[3,4-f][1,2,4]triazin-8(7H)-one (3) were obtained via the 18-crown-6-ether catalyzed room temperature reactionof 6-amino-3-methyl-1,2,4-triazolo[3,4-f][1,2,4]triazin-8(7H)-one (1) with potassiumcarbonate and allyl bromide in dry acetone. The structures of these two derivatives wereverified by 2D-NMR measurements, including gHSQC and gHMBC measurements. Theminor compound 2 may possess aromatic character. A single crystal X-ray diffractionexperiment indicated that the major compound 3 crystallizes from dimethyl sulfoxide in themonoclinic space group P21 /n and its molecular structure includes an attached dimethylsulfoxide molecule, resulting in the molecular formula C10 H16 N6 O2 S. Molecular structuresof 3 are linked by extensive intermolecular N-H···N hydrogen bonding [graph set C 1 (7)]. 1Each molecule is attached to the dimethyl sulfoxide oxygen via N-H···O intermolecularhydrogen bonding. The structure is further stabilized by π-π stacking interactions.
p. 453-463
Received: 7 June 2006; in revised form: 20 June 2006 / Accepted: 20 June 2006 / Published: 21 June 2006
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| Download PDF Full-text (239 KB) Abstract: New Schiff bases have been prepared by reacting 3-hydroxy-4-pyridine- carboxaldehyde with various amines. NMR spectroscopic methods provided clear evidence that the Schiff bases exist in the solid state and in solution as hydroxyimino tautomers with the E-configuration. A study of the stabilities of the tautomeric forms and the different conformers has been carried out using density functional calculations at the B3LYP/6-31G** level.
p. 464-468
Received: 10 May 2006; in revised form: 15 June 2006 / Accepted: 19 June 2006 / Published: 21 June 2006
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| Download PDF Full-text (57 KB) Abstract: The reaction of 1,4-Dihydroxyanthraquinone with diamines was carried out in thepresence of CuCl2 , CuCl in the ionic liquid [Bmim]PF6 , [Bmim]BF4 or [Bmim]Cl·CuCl.
p. 469-477
Received: 10 May 2006; in revised form: 20 June 2006 / Accepted: 21 June 2006 / Published: 21 June 2006
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| Download PDF Full-text (77 KB) Abstract: A series of new 1,2/1,3-bis[o-(N-methylidenamino-3-aryl-5-phenyl-4H-1,2,4-triazole-4-yl)phenoxy]ethane/propane derivatives 4 were prepared in good yields bytreatment of 4-amino-3-aryl-5-phenyl-4H-1,2,4-triazoles 2 with certain bis-aldehydes 1.Compounds 4 were reduced with NaBH4 to afford the corresponding 1,2/1,3-bis[o-(N-methylamino-3-aryl-5-phenyl-4H-1,2,4-triazole-4-yl)phenoxy]ethane/propane derivatives5. All new compounds were characterized by IR, 1 H-NMR, 13 C-NMR and mass spectraldata.
p. 478-485
Received: 29 April 2006; in revised form: 13 June 2006 / Accepted: 15 June 2006 / Published: 23 June 2006
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| Download PDF Full-text (225 KB) Abstract: The molecular recognition features of tolbutamide with four synthetic hosts have been studied by means of NMR titrations, NOESY experiments and Monte Carlo (MC) conformational search. The interaction strength and the most probable structure reveal new insights on the recognition phenomena of this urea derivative in comparison with close related compounds.
p. 486-495
Received: 26 April 2006; in revised form: 23 May 2006 / Accepted: 29 May 2006 / Published: 23 June 2006
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| Download PDF Full-text (76 KB) Abstract: Direct, solid phase synthesis of an oligonucleotide conjugate of the antibioticdrug metronidazole was accomplished by the phosphoramidite method. Removal ofprotecting groups and cleavage from the controlled pore glass (CPG) solid support wassuccessful using mild conditions (20% Et3 N in pyridine, then conc. NH3 (aq) at rt for 30min) whereas standard conditions (conc. NH3 (aq) at 55 °C for 16 h) cleaved the drug.
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