- Convenient and efficient method for the iodination of aromatic amines by pyridinium iodochloride
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A simple and efficient method for the iodination of aromatic amines using pyridinium iodochloride (PyICl) in methanol as solvent is reported. Mild reaction conditions, short reaction time, and good to excellent yields of the product are the noteworthy advantages of the method. Pyridinium iodochloride is an efficient solid iodinating reagent and can be handled safely. Copyright Taylor & Francis Group, LLC.
- Khansole, Sandeep V.,Junne, Subhash B.,Sayyed, Mudassar A.,Vibhute, Yeshwant B.
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p. 1792 - 1798
(2008/09/20)
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- Synthesis, characterization and antimicrobial studies on some newer imidazole analogs
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A novel series of 3,5-diiodo-4-(2-methyl-1H-imidazol-5-yl)benzoic acid analogs of amino acids, dipeptides and tripeptides was synthesized by using dicyclohexylcarbodiimide and diisopropylcarbodiimide (DCC/DIPC) as coupling agents and triethylamine (TEA) as base. Structures of all the newly synthesized compounds were confirmed by elemental analysis and IR, 1H NMR, 13C NMR and mass spectral data. Imidazolopeptides were investigated for their antimicrobial activity and some of newly synthesized compounds 2c, 2d, 2h and their hydrolyzed analogs 3b, 3d exhibited potent bioactivity against pathogenic fungi Candida albicans and dermatophytes Trichophyton mentagrophytes and Microsporum audouinii with MIC values of 12.5-6 μg/ml, as compared to the reference drug - griseofulvin. In addition, moderate activity against gram negative bacteria Pseudomonas aeruginosa and Klebsiella pneumoniae was also observed for synthesized imidazolopeptides. Oesterreichische Apotheker-Verlagsgesellschaft m. b. H.
- Dahiya, Rajiv
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p. 217 - 239
(2008/12/22)
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- Synthetic studies on novel benzimidazolopeptides with antimicrobial, cytotoxic and anthelmintic potential
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Four substituted benzimidazolyl-benzoic/salicylic acids 5-8 were synthesized by interaction of 5,6-dimethyl-/6-nitrobenzimidazoles with diazotized substituted/unsubstituted aminobenzoic acids in the presence of cupric chloride. The coupling of compounds 5-8 with different amino acid ester hydrochlorides/dipeptide/tripeptide/tetrapeptide methyl esters afforded novel benzimidazolopeptide derivatives 5a-f, 6a-h, 7a-g and 8a-g. The structures of all newly synthesized compounds were established on the basis of analytical, IR, 1H NMR, 13C NMR and mass spectral data. Selected peptide ester derivatives were further hydrolyzed by using lithium hydroxide (LiOH) to yield corresponding acid derivatives 5ba-da, 6ea-ga, 7ca-ea and 8ea-ga. All peptide derivatives were screened for their antimicrobial, anthelmintic and cytotoxic activities. Almost all newly synthesized benzimidazolopeptides have shown moderate to good anthelmintic activity against all three earthworm species and good antimicrobial activity against pathogenic fungal strains Candida albicans and Aspergillus niger, gram negative bacterial strains Pseudomonas aeruginosa and Escherichia coli. Compounds 8g and 8ga possessed significant cytotoxic activity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines.
- Dahiya, Rajiv,Pathak, Devender
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p. 772 - 798
(2008/02/13)
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- Iodoaminopotentidine and related compounds: A new class of ligands with high affinity and selectivity for the histamine H2 receptor
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The synthesis and biological evaluation of a new class of histamine H2 antagonists with N-cyano-N'-[ω-[3-(1- piperidinylmethyl)phenoxy]alkyl]guanidine partial structure are described as part of an extensive research program to find model compounds for the development of new radioligands with high H2 affinity and specific activity. High receptor affinity is achieved by an additional (substituted) aromatic ring, which is connected with the third guanidine N by a carbon chain spacer and an amine, carboxamide, ester, or sulfonamide link ('polar group'). In functional studies for H2 antagonistic activity and other pharmacological actions [e.g. H1 antihistaminic, antimuscarinic, antiadrenergic (α1, β1), 5-HT2 blocking activity] in the isolated guinea pig atrium and ileum and rat aorta and tail artery, the compounds proved to be highly potent and selective histamine H2 receptor antagonists. The H2 antagonistic activity is mainly depending on the length of both the N'-alkyl chain (chain A) and the N''-spacer (chain B). Compounds with a C3 chain A and a C2 chain B are most potent in the preferred group of substances, i.e., the carboxamide series. A wide variety of substituents at the aromatic ring is tolerated, among them iodine, amino, and azido groups. These compounds are up to 32 times more potent than cimetidine in the isolated guinea pig right atrium. The replacement of the carboxamide by an ester group (44c) is well tolerated, while replacement of the cyanoguanidine by an urea group results in nearly 100-fold decrease in activity (46c,e). The iodinated benzamides are among the most potent H2 antagonists known so far. The [125I]-labeled form of 31f ([125]iodoaminopotendine, [125I]-N-[2-(4-amino-3-iodobenzamido)ethyl]- N'-cyano-N''-[3-[3-(1-piperidinylmethyl)phenoxy]propyl]guanidine) and its photolabile analogue 31h ([125I]iodoazidopotentidine, [125I]-N-[2-(4- azido-3-iodobenzamido)ethyl]-N'-cyano-N''-[3-[3-(1-piperidinyl- methyl)phenoxy]propyl]guanidine) proved to be useful probes for reversible and irreversible labeling of the histamine H2 receptor. Radioligand binding studies in guinea pig cerebral membranes revealed considerably higher H2 receptor affinity for 31f (pK(i) = 9.15), 31h (pK(i) = 8.58), and some analogues than functional experiments (guinea pig atrium), presumably reflecting an easier access to the H2 receptors in membranes.
- Hirschfeld,Buschauer,Elz,Schunack,Ruat,Traiffort,Schwartz
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p. 2231 - 2238
(2007/10/02)
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