76
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Tsuchiya S, Sunazuka T, Hirose T, Mori R, Tanaka T, Iwatsuki M, Omura S. Asymmetric Total Synthesis of (+)-K01-0509 B: Determination of Absolute Configuration. Org Lett 2006; 8:5577-80. [PMID: 17107076 DOI: 10.1021/ol062282z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
K01-0509 B is a novel natural product which contains a carbamoylated cyclic guanidine. Our asymmetric total synthesis features a Sharpless asymmetric epoxidation and a stereocontrolled construction of the cyclic guanidine via an asymmetric nitroaldol reaction, followed by intramolecular SN2 cyclization. These reactions allowed the cyclic guanidine and the adjacent hydroxy group to be assembled, facilitating the asymmetric total synthesis and determination of the absolute stereochemistry of K01-0509 B. [reaction: see text].
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77
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Arnold MA, Day KA, Durón SG, Gin DY. Total synthesis of (+)-batzelladine A and (-)-batzelladine D via [4 + 2]-annulation of vinyl carbodiimides with N-alkyl imines. J Am Chem Soc 2006; 128:13255-60. [PMID: 17017806 PMCID: PMC2610335 DOI: 10.1021/ja063860+] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A diastereoselective [4 + 2]-annulation of vinyl carbodiimides with chiral N-alkyl imines has been developed to access the stereochemically rich polycyclic guanidine cores of the batzelladine alkaloids. Application of this strategy, together with additional key steps such as long-range directed hydrogenation and diastereoselective intramolecular iodo-amination, led to highly convergent total syntheses of (-)-batzelladine D and (+)-batzelladine A with excellent stereocontrol.
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78
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Li J, Zheng M, Tang W, He PL, Zhu W, Li T, Zuo JP, Liu H, Jiang H. Syntheses of triazole-modified zanamivir analogues via click chemistry and anti-AIV activities. Bioorg Med Chem Lett 2006; 16:5009-13. [PMID: 16876409 DOI: 10.1016/j.bmcl.2006.07.047] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 06/05/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
Sixteen novel 4-triazole-modified zanamivir (1) analogues were synthesized using the click reactions, and their inhibitory activities against avian influenza virus (AIV, H5N1) were determined. Compound 3b exerts promising inhibitory activity with EC(50) of 6.4 microM, which is very close to that of zanamivir (EC(50) = 2.8 microM). Molecular modeling provided the information about the binding model between inhibitors and neuraminidase, which are in good agreement with inhibitory activities.
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79
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Cole DC, Manas ES, Stock JR, Condon JS, Jennings LD, Aulabaugh A, Chopra R, Cowling R, Ellingboe JW, Fan KY, Harrison BL, Hu Y, Jacobsen S, Jin G, Lin L, Lovering FE, Malamas MS, Stahl ML, Strand J, Sukhdeo MN, Svenson K, Turner MJ, Wagner E, Wu J, Zhou P, Bard J. Acylguanidines as Small-Molecule β-Secretase Inhibitors. J Med Chem 2006; 49:6158-61. [PMID: 17034121 DOI: 10.1021/jm0607451] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACE1 is an aspartyl protease responsible for cleaving amyloid precursor protein to liberate Abeta, which aggregates leading to plaque deposits implicated in Alzheimer's disease. We have identified small-molecule acylguanidine inhibitors of BACE1. Crystallographic studies show that these compounds form unique hydrogen-bonding interactions with the catalytic site aspartic acids and stabilize the protein in a flap-open conformation. Structure-based optimization led to the identification of potent analogs, such as 10d (BACE1 IC(50) = 110 nM).
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80
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Hirsh AJ, Molino BF, Zhang J, Astakhova N, Geiss WB, Sargent BJ, Swenson BD, Usyatinsky A, Wyle MJ, Boucher RC, Smith RT, Zamurs A, Johnson MR. Design, synthesis, and structure-activity relationships of novel 2-substituted pyrazinoylguanidine epithelial sodium channel blockers: drugs for cystic fibrosis and chronic bronchitis. J Med Chem 2006; 49:4098-115. [PMID: 16821771 DOI: 10.1021/jm051134w] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amiloride (1), the prototypical epithelial sodium channel (ENaC) blocker, has been administered with limited success as aerosol therapy for improving pulmonary function in patients with the genetic disorder cystic fibrosis. This study was conducted to synthesize and identify more potent, less reversible ENaC blockers, targeted for aerosol therapy and possessing minimal systemic renal activity. A series of novel 2-substituted acylguanidine analogues of amiloride were synthesized and evaluated for potency and reversibility on bronchial ENaC. All compounds tested were more potent and less reversible at blocking sodium-dependent short-circuit current than amiloride. Compounds 30-34 showed the greatest potency on ENaC with IC(50) values below 10 nM. A regioselective difference in potency was found (compounds 30, 39, and 40), whereas no stereospecific (compounds 33, 34) difference in potency on ENaC was displayed. Lead compound 32 was 102-fold more potent and 5-fold less reversible than amiloride and displayed the lowest IC(50) value ever reported for an ENaC blocker.
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81
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Tian X, Mishra RK, Switzer AG, Hu XE, Kim N, Mazur AW, Ebetino FH, Wos JA, Crossdoersen D, Pinney BB, Farmer JA, Sheldon RJ. Design and synthesis of potent and selective 1,3,4-trisubstituted-2-oxopiperazine based melanocortin-4 receptor agonists. Bioorg Med Chem Lett 2006; 16:4668-73. [PMID: 16766182 DOI: 10.1016/j.bmcl.2006.05.087] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Revised: 05/23/2006] [Accepted: 05/30/2006] [Indexed: 10/24/2022]
Abstract
The design and synthesis of a series of potent 1,3,4-trisubstituted-2-oxopiperazine based MC4 agonists are described. The tripeptidomimetic analogs (12a,b and 23) and the dipeptidomimetic 27 displayed single-nanomolar binding affinity and agonist potency for MC4R and excellent selectivity for MC4R relative to MC1R.
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82
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Jain ML, Bruice TC. Solid-phase synthesis of positively charged deoxynucleic guanidine (DNG) oligonucleotide incorporating 7-deazaguanine bases. Bioorg Med Chem 2006; 14:7333-46. [PMID: 16945544 DOI: 10.1016/j.bmc.2006.05.074] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2006] [Revised: 05/31/2006] [Accepted: 05/31/2006] [Indexed: 10/24/2022]
Abstract
DNG nucleotides represent a positively charged DNA analog in which the negatively charged phosphodiester linkages of DNA are replaced by positively charged guanidinium linkages. We report herein the synthesis of 3'-end, middle, and 5'-end monomers required for the synthesis of a DNG sequence in which the natural guanine base is replaced by 7-deazaguanine (c(7)G). 7-Deazaguanine nucleobase was chosen because of their unique glycoside bond stability and their ability to prevent G-quartet formation. A facile and high yield two-step synthesis of xylo-7-deazaguanine 7, a key intermediate for introducing 3'-amino functionality, is carried out under Mitsunobu conditions. Subsequently, the 3'-Fmoc-protected thiourea monomers 13 and 19 were prepared from 7 via their corresponding 3'-amino-7-deazaguanines 11 and 18, respectively. The smooth coupling of these thiourea monomers with monomethoxytrityl (MMTr)-protected 3'-end monomer 25, prepared from 5, occurred on solid phase in 3'-->5' direction. The resultant trimeric HO-c(7)Ggc(7)Ggc(7)G-OH (1) has been designed to be included into DNA using standard DNA synthesis technology. The combination of C-c(7)G base pairing and electrostatic association of phosphodiester and guanidinium backbone allows the small synthesized DNG trimer 1 to form 1:1 complex with DNA-C pentamer.
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83
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Xie SX, Petrache G, Schneider E, Ye QZ, Bernhardt G, Seifert R, Buschauer A. Synthesis and pharmacological characterization of novel fluorescent histamine H2-receptor ligands derived from aminopotentidine. Bioorg Med Chem Lett 2006; 16:3886-90. [PMID: 16730977 DOI: 10.1016/j.bmcl.2006.05.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 05/11/2006] [Accepted: 05/13/2006] [Indexed: 11/25/2022]
Abstract
In an effort to develop a non-radioactive alternative to the [3H]tiotidine and [125I]iodoaminopotentidine binding assays for the histamine H2-receptor (H2R), primary amines related to aminopotentidine were prepared and coupled with the succinimidyl esters of the bulky fluorescent dyes S0536 and BODIPY 650/665-X. The primary amines exhibited different degrees of antagonistic potency at the human and guinea pig H2R. Surprisingly, one compound (5) coupled to the cyanine dye S0536 acted as potent partial agonist/antagonist at the H2R (KB approximately 50 nM; EC50 approximately 100-150 nM). Compounds coupled to the BODIPY dye exhibited moderately high H2R-affinity, too. Thus, the H2R accommodates bulky fluorophores, probably through interaction with extracellular receptor domains. The compounds presented herein provide a starting point for the optimization of fluorescent H2R ligands with respect to affinity and fluorescence as valuable tools to analyze the molecular mechanisms of H2R activation.
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84
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Dardonville C, Barrett MP, Brun R, Kaiser M, Tanious F, Wilson WD. DNA binding affinity of bisguanidine and bis(2-aminoimidazoline) derivatives with in vivo antitrypanosomal activity. J Med Chem 2006; 49:3748-52. [PMID: 16759117 DOI: 10.1021/jm060295c] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new antitrypanosomal hit compound that cures an acute (STIB 900) mouse model of Trypanosoma brucei rhodesiense trypanosomiasis is described. This bis(2-aminoimidazolinium) dicationic compound proved to be an excellent DNA minor groove binder, suggesting a possible mechanism for its trypanocidal activity. From these studies, the 4,4'-diaminodiphenylamine skeleton emerged as a good scaffold for antitrypanosomal drugs.
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85
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Sieńczyk M, Oleksyszyn J. Inhibition of trypsin and urokinase by Cbz-amino(4-guanidinophenyl)methanephosphonate aromatic ester derivatives: The influence of the ester group on their biological activity. Bioorg Med Chem Lett 2006; 16:2886-90. [PMID: 16546384 DOI: 10.1016/j.bmcl.2006.03.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 03/01/2006] [Accepted: 03/02/2006] [Indexed: 10/24/2022]
Abstract
The urokinase plasminogen activator is a trypsin-like serine protease, important in tumor development. Here, we report the synthesis and biochemical evaluation of selective and potent diaryl esters of phosphonic-type inhibitors for urokinase. We have found that the substituted phenyl ester ring has a strong influence on the inhibitory activity of these compounds. This led to the most potent phosphonic inhibitor for uPA synthesized to date.
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86
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Mourer M, Duval RE, Finance C, Regnouf-de-Vains JB. Functional organisation and gain of activity: The case of the antibacterial tetra-para-guanidinoethyl-calix[4]arene. Bioorg Med Chem Lett 2006; 16:2960-3. [PMID: 16563763 DOI: 10.1016/j.bmcl.2006.02.072] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Revised: 02/23/2006] [Accepted: 02/25/2006] [Indexed: 11/17/2022]
Abstract
The antibacterial activities of the para-guanidinoethylphenol and of its cyclic tetramer, the tetra-para-guanidinoethyl-calix[4]arene, have been evaluated on reference gram-positive and gram-negative bacteria. Antibiotic disk diffusion assays completed by micromethod technique were employed to determine if a synergistic effect could be expected from the spatial organisation of the monomer into its cyclic tetrameric analogue. Disk diffusion assays and microdilution experiments revealed better properties for the calixarene species, with a real and important gain of activity with regards to the monomer.
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87
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Hanson J, Reynaud D, Qiao N, Devel P, Moray AL, Renard JF, Kelley LP, Winum JY, Montero JL, Kinsella BT, Pirotte B, Pace-Asciak CR, Dogné JM. Synthesis and Pharmacological Evaluation of Novel Nitrobenzenic Thromboxane Modulators as Antiplatelet Agents Acting on Both the Alpha and Beta Isoforms of the Human Thromboxane Receptor. J Med Chem 2006; 49:3701-9. [PMID: 16759113 DOI: 10.1021/jm060108a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thromboxane A(2) (TXA(2)) is an arachidonic acid metabolite involved in pathologies such as stroke, myocardial infarction, and atherosclerosis. Consequently, the design of TXA(2) receptor (TP) antagonists remains of great interest in cardiovascular medicine. The actions of TXA(2) are mediated by its specific G-protein coupled receptor of which two alternative spliced isoforms, TPalpha and TPbeta, have been described in humans. In this study, we report the synthesis of a series of original N-alkyl-N'-[2-(cycloalkyl, alkylaryl)-5-nitrobenzenesulfonyl]urea and N-alkyl-N'-[2-(alkylaryl)-5-nitrobenzenesulfonyl]-N' '-cyanoguanidines and outline their pharmacological evaluation using the individual TPalpha and TPbeta isoforms. Among compounds analyzed, several of them exhibited greater affinity and/or functional activity for either TPalpha or TPbeta. The most promising molecules were also found to be antiplatelet agents. From the present results, structural features involved in isoform selectivity can be proposed, and thereby several lead compounds have been identified for the further development of selective TP isoform antagonists.
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88
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Wan ZK, Wacharasindhu S, Binnun E, Mansour T. An Efficient Direct Amination of Cyclic Amides and Cyclic Ureas. Org Lett 2006; 8:2425-8. [PMID: 16706542 DOI: 10.1021/ol060815y] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] An efficient one-step amination of cyclic amides and ureas has been developed. Treatment of cyclic amides and cyclic ureas with BOP in the presence of DBU in various solvents led to the formation of cyclic amidines and cyclic guanidines in good to excellent yields. Concise syntheses of biologically intriguing kinetin and potent kinase inhibitor olomoucin were thus achieved in just one and two steps, respectively.
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89
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Otón F, Tarraga A, Molina P. A Bis-guanidine-Based Multisignaling Sensor Molecule That Displays Redox-Ratiometric Behavior or Fluorescence Enhancement in the Presence of Anions and Cations. Org Lett 2006; 8:2107-10. [PMID: 16671793 DOI: 10.1021/ol060495i] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[structure: see text]The guanidine bridge in the new structural motif [3,3]ferrocenophane acts as a dual binding site for anions and metal ions. Sensing of anions (Cl(-), F(-), NO(3)(-), HSO(4)(-), and H(2)PO(4)(-)) takes place by redox-ratiometric measurements, whereas metal ion (Zn(2+), Ni(2+), and Cd(2+)) recognition is achieved by fluorescence measurements.
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90
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Bi X, Lopez C, Bacchi CJ, Rattendi D, Woster PM. Novel alkylpolyaminoguanidines and alkylpolyaminobiguanides with potent antitrypanosomal activity. Bioorg Med Chem Lett 2006; 16:3229-32. [PMID: 16616495 DOI: 10.1016/j.bmcl.2006.03.048] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 03/13/2006] [Accepted: 03/14/2006] [Indexed: 12/01/2022]
Abstract
A series of polyaminoguanidines and polyaminobiguanides were synthesized and evaluated as potential antitrypanosomal agents. These analogues inhibit trypanothione reductase (TR) with IC50 values as low as 0.95 microM, but do not inhibit the closely related human enzyme glutathione reductase (GR). The most effective analogues, 7a, 7b and 8d, inhibited parasitic growth in vitro with IC50 values of 0.18, 0.09 and 0.18 microM, respectively. These agents represent a promising new class of potential antitrypanosomal agents.
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91
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Fresneda PM, Delgado S, Francesch A, Manzanares I, Cuevas C, Molina P. Synthesis and cytotoxic evaluation of new derivatives of the marine alkaloid variolin B. J Med Chem 2006; 49:1217-21. [PMID: 16451088 DOI: 10.1021/jm051090r] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The marine alkaloid variolin B 2 and eight synthetic derivatives with different substituents at positions C-5 and C-7 have been tested in a panel of sixteen human tumor cell lines to evaluate their cytotoxic potential.
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92
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Abstract
An overview of marine natural products synthesis during 2004 is provided. As with the previous installment of this series, the emphasis is on total syntheses of molecules of contemporary interest, new total syntheses, and syntheses that have resulted in structure confirmation or stereochemical assignments.
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93
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Abstract
Solid-phase synthesis is a powerful tool for achieving high-throughput chemistry. This review discusses recent diverse examples from my group: the solid-phase synthesis of unsymmetrical guanidines, polymer-supported versions of cyclooctadiene and 9-BBN, a triflate-like linker, the synthesis of tetrahydro-beta-carbolines by the acyliminium Pictet-Spengler reaction, and a total synthesis of the antimycobacterial cyclic depsipeptide natural product kahalalide A.
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94
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95
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Wannaporn D, Ishikawa T. Polymer-supported and polymeric chiral guanidines: Preparation and application to the asymmetric Michael reaction of iminoacetate with methyl vinyl ketone. Mol Divers 2005; 9:321-31. [PMID: 16311809 DOI: 10.1007/s11030-005-8116-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Accepted: 12/21/2004] [Indexed: 10/25/2022]
Abstract
Polymer-supported and polymeric chiral guanidines carrying an imidazolidine skeleton are designed as polymer-based base catalysts. Thus, (R)-2-[(S)-1-hydroxymethyl-2-phenylethylimino]-4-phenylimidazolidine was newly prepared from (R)-phenylglycine as the key functional unit of these guanidines. Application of the polymer-based chiral guanidines to the asymmetric Michael reaction of t-butyl diphenyliminoacetate with MVK led to expected asymmetric induction in the Michael adduct with moderate enantioselectivity in the use of the latter polymeric chiral guanidines.
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96
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Arafa RK, Brun R, Wenzler T, Tanious FA, Wilson WD, Stephens CE, Boykin DW. Synthesis, DNA affinity, and antiprotozoal activity of fused ring dicationic compounds and their prodrugs. J Med Chem 2005; 48:5480-8. [PMID: 16107146 DOI: 10.1021/jm058190h] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dicationic guanidine, N-alkylguanidine, and reversed amidine derivatives of fused ring systems have been synthesized from their corresponding bis-amines. DNA binding studies suggest that the diguanidines and the N-alkyl diguanidines fluorenes bind in the minor groove in a manner similar to that of the previously reported dicationic carbazole derivatives. The diguanidines and the N-alkyl diguanidines showed promising in vitro activity against both Trypanosoma brucei rhodesiense and Plasmodium falciparum. Promising in vivo biological results were obtained for the dicationic N-isopropylguanidino-9H-fluorene, giving 4/4 cures of the treated animals in the STIB900 animal model for African trypanosomiasis. The N-methyl analogue showed high activity as well. In addition, with the goal of enhancing the oral bioavailability, two novel classes of potential guanidine prodrugs were prepared. The N-alkoxyguanidine derivatives were not effective as prodrugs. In contrast, a number of the carbamates showed promising activity. The value of the carbamate prodrugs was clearly demonstrated by the results, which gave 4/4 cures on oral administration in the STIB900 mouse model.
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97
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Zhang Z, Fan E. Solid-Phase and Solution-Phase Syntheses of Oligomeric Guanidines Bearing Peptide Side Chains. J Org Chem 2005; 70:8801-10. [PMID: 16238312 DOI: 10.1021/jo051226t] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] Synthetic strategies for preparing N,N'-bridged oligomeric guanidines bearing peptide side chains both on solid support and in solution are presented. Monomers are prepared from common alpha-amino acids and therefore contain conventionally protected peptide side chains. The side chains include alkyl, aromatic, hydroxyl, amino, carboxylic acid, and amide functional groups. Oligomer elongation utilizes acid-sensitive sulfonyl activated thiourea through the formation of carbodiimide intermediate. With proper preparation of monomers, synthesis of oligomer can be performed in two directions (equivalent to N to C terminal or C to N terminal in a peptide sequence) with excellent efficiency.
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98
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Arnold MA, Durón SG, Gin DY. Diastereoselective [4+2] annulation of vinyl carbodiimides with N-alkyl imines. Asymmetric synthetic access to the batzelladine alkaloids. J Am Chem Soc 2005; 127:6924-5. [PMID: 15884915 DOI: 10.1021/ja0519029] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A diastereoselective [4+2] annulation of vinyl carbodiimides with chiral N-alkyl imines has been developed to access the stereochemically rich tricyclic core of the batzelladine alkaloids. Its application to the asymmetric synthesis of batzelladine D permitted the use of long-range, directed hydrogenation and stereoselective intramolecular iodoamination as additional key steps to establish the remaining stereocenters within the natural product with excellent stereocontrol.
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99
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Macías B, Villa MV, Sanz F, Borrás J, González-Alvarez M, Alzuet G. Cu(II) complexes with a sulfonamide derived from benzoguanamine. Oxidative cleavage of DNA in the presence of H2O2 and ascorbate. J Inorg Biochem 2005; 99:1441-8. [PMID: 15894377 DOI: 10.1016/j.jinorgbio.2005.04.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 01/25/2005] [Accepted: 03/31/2005] [Indexed: 11/18/2022]
Abstract
Reaction between benzoguanamine (2,4-diamino-6-phenyl-1,3,5-triazine) and 2-mesitylenesulfonyl chloride leads to formation of a sulfonamide able to form two mononuclear Cu(II) complexes with a CuL(2) stoichiometry. The local environment of the metal cation is a distorted octahedron, with two ligands and two solvent molecules; both complexes crystallize in the monoclinic structure, space group P2(1), with Z=2. In the presence of ascorbate/H(2)O(2,) the two complexes significantly cleavage double-strand pUC18 DNA plasmid. Both complexes exhibit more nuclease efficiency that the copper phenantroline complex. From scavenging reactive oxygen studies we conclude that the hydroxyl radical and a singlet oxygen-like entity, such a peroxide copper complex, are the radical species involved in the DNA damage.
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100
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Hamilton SK, Wilkinson DE, Hamilton GS, Wu YQ. Microwave-Assisted Synthesis ofN,N‘-Diaryl Cyanoguanidines. Org Lett 2005; 7:2429-31. [PMID: 15932215 DOI: 10.1021/ol050728q] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] A mild, efficient, and high-yielding method for the synthesis of N,N'-diaryl cyanoguanidines from their corresponding thioureas under microwave-assisted conditions is described. A series of cyanoguanidines were synthesized containing both electron-donating and electron-withdrawing substituents. The reactions were facilitated by the use of polar solvents along with moderate temperatures.
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