Search results for: David W. Boykin

Items from 1 to 20 out of 101 results

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Facile synthesis of benzobisimidazole and bibenzimidazole‐based bisnitriles as potential precursors for DNA minor groove binders

Abdelbasset A. Farahat, Satori Iwamoto, Michael Roche, David W. Boykin

Journal of Heterocyclic Chemistry > 58 > 12 > 2280 - 2286

The synthesis of bisnitrile derivatives of benzobisimidazole and bibenzimidazole in a good yield is described in detail for the first time. Nucleophilic substitution of 1,5‐difluoro‐2,4‐dinitrobenzene using different amines produced the intermediate diamines that were reduced using sodium borohydride/Pd(C) to produce the tetramines. These tetramines were allowed to couple with different aldehydes...

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Small Sequence‐Sensitive Compounds for Specific Recognition of the G⋅C Base Pair in DNA Minor Groove

Abdelbasset A. Farahat, Pu Guo, Hadir Shoeib, Ananya Paul, more

Chemistry – A European Journal > 26 > 20 > 4539 - 4551

A series of small diamidines with thiophene and modified N‐alkylbenzimidazole σ‐hole module represent specific binding to single G⋅C base pair (bp) DNA sequence. The variation of N‐alkyl or aromatic rings were sensitive to microstructures of the DNA minor groove. Thirteen new compounds were synthesized to test their binding affinity and selectivity. The dicyanobenzimidazoles needed to synthesize the...

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Hierarchical Nanotube Self‐Assembly of DNA Minor Groove‐Binding Ligand DB921 via Alkali Halide Triggering

Ryo Mizuta, Juliette M. Devos, Theyencheri Narayanan, Mizar Oliva, more

Macromolecular Symposia > 386 > 1 > n/a - n/a

A systematic study into a novel self‐assembling system is presented whereby the small molecule DB921 forms nearly monodisperse nanotubes upon addition of a suitable salt. Small‐angle X‐ray scattering and negative stain transmission electron microscopy are employed as the principal characterization methods to study both the fundamental assembly processes and reaction kinetics. The assembly is found...

article

Indole and Benzimidazole Bichalcophenes: Synthesis, DNA Binding and Antiparasitic Activity

Abdelbasset A. Farahat, Mohamed A. Ismail, Arvind Kumar, Tanja Wenzler, more

European Journal of Medicinal Chemistry > 2018 > 143 > C > 1590-1596

A novel series of indole and benzimidazole bichalcophene diamidine derivatives were prepared to study their antimicrobial activity against the tropical parasites causing African sleeping sickness and malaria. The dicyanoindoles needed to synthesize the target diamidines were obtained through Stille coupling reactions while the bis-cyanobenzimidazoles intermediates were made via condensation/cyclization...

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Investigation of the electrostatic and hydration properties of DNA minor groove-binding by a heterocyclic diamidine by osmotic pressure

Noa Erlitzki, Kenneth Huang, Suela Xhani, Abdelbasset A. Farahat, more

Biophysical Chemistry > 2017 > 231 > C > 95-104

Previous investigations of sequence-specific DNA binding by model minor groove-binding compounds showed that the ligand/DNA complex was destabilized in the presence of compatible co-solutes. Inhibition was interpreted in terms of osmotic stress theory as the uptake of significant numbers of excess water molecules from bulk solvent upon complex formation. Here, we interrogated the AT-specific DNA complex...

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Inhibition of the myeloid master regulator PU.1 as a therapeutic strategy in acute myeloid leukemia

Ileana Antony-Debre, Joana Leite, Ananya Paul, Kelly Mitchell, more

Experimental Hematology > 2017 > 53 > S > S133

article

Exploration of DAPI analogues: Synthesis, antitrypanosomal activity, DNA binding and fluorescence properties

Abdelbasset A. Farahat, Arvind Kumar, Martial Say, Tanja Wenzler, more

European Journal of Medicinal Chemistry > 2017 > 128 > C > 70-78

The DAPI structure has been modified by replacing the phenyl group with substituted phenyl or heteroaryl rings. Twelve amidines were synthesized and their DNA binding, fluorescence properties, in vitro and in vivo activities were evaluated. These compounds are shown to bind in the DNA minor groove with high affinity, and exhibit superior in vitro antitrypanosomal activity to that of DAPI. Six new...

article

Antiprotozoal agents as water soluble singlet oxygen photosensitizers: Imidazo[1,2-a]pyridine and 5,6,7,8-tetrahydro-imidazo[1,2-a]pyridine derivatives

Ayman A. Abdel-Shafi, Ahlam M. Fathi, Mohamed A. Ismail, David W. Boykin

Journal of Luminescence > 2017 > 181 > C > 164-170

In this study we report on the photophysical properties of some imidazo[1,2-a]pyridine and 5,6,7,8-tetrahydroimidazo[1,2-a]pyridine derivatives and their efficiency as singlet oxygen photosensitizers in aqueous media. In aqueous solution, the wavelengths of maximum absorption are in the range of 269–307nm, while the wavelengths of maximum emission cover the range of 357–462nm. It has been found that...

article

Synthesis, DNA binding and antitrypanosomal activity of benzimidazole analogues of DAPI

Abdelbasset A. Farahat, Cheree Bennett-Vaughn, Ekaterina M. Mineva, Arvind Kumar, more

Bioorganic & Medicinal Chemistry Letters > 2016 > 26 > 24 > 5907-5910

A series of novel benzimidazole diamidines were prepared from the corresponding dicyano analogues either by applying Pinner methodology (5a–c, 10 and 13a) or by making amidoximes intermediates that were reduced to the corresponding amidines (15a–c). The new amidines were evaluated in vitro against the protozoan parasite Trypanosoma brucei rhodesiense (T. b. r.). The thiophene analogue 5b and the N-methyl...

article

The Thiophene “Sigma‐Hole” as a Concept for Preorganized, Specific Recognition of G⋅C Base Pairs in the DNA Minor Groove

Pu Guo, Ananya Paul, Arvind Kumar, Abdelbasset A. Farahat, more

Chemistry – A European Journal > 22 > 43 > 15404 - 15412

In spite of its importance in cell function, targeting DNA is under‐represented in the design of small molecules. A barrier to progress in this area is the lack of a variety of modules that recognize G⋅C base pairs (bp) in DNA sequences. To overcome this barrier, an entirely new design concept for modules that can bind to mixed G⋅C and A⋅T sequences of DNA is reported herein. Because of their successes...

article

Synthesis and pharmacological evaluation of mono-arylimidamides as antileishmanial agents

Xiaohua Zhu, Abdelbasset A. Farahat, Meena Mattamana, April Joice, more

Bioorganic & Medicinal Chemistry Letters > 2016 > 26 > 10 > 2551-2556

Arylimidamide (AIA) compounds containing two pyridylimidamide terminal groups (bis-AIAs) possess outstanding in vitro antileishmanial activity, and the frontrunner bis-AIA DB766 (2,5-bis[2-(2-isopropoxy)-4-(2-pyridylimino)aminophenyl]furan) is active in visceral leishmaniasis models when given orally. Eighteen compounds containing a single pyridylimidamide terminal group (mono-AIAs) were synthesized...

article

Mixed up minor groove binders: Convincing A·T specific compounds to recognize a G·C base pair

Ananya Paul, Rupesh Nanjunda, Arvind Kumar, Sarah Laughlin, more

Bioorganic & Medicinal Chemistry Letters > 2015 > 25 > 21 > 4927-4932

DNA minor-groove-binding compounds have limited biological applications, in part due to problems with sequence specificity that cause off-target effects. A model to enhance specificity has been developed with the goal of preparing compounds that bind to two AT sites separated by G·C base pairs. Compounds of interest were probed using thermal melting, circular dichroism, mass spectrometry, biosensor-SPR,...

article

Pentamidine analogs as inhibitors of [3H]MK-801 and [3H]ifenprodil binding to rat brain NMDA receptors

Michael L. Berger, Dorota Maciejewska, Jean Jacques Vanden Eynde, Madhusoodanan Mottamal, more

Bioorganic & Medicinal Chemistry > 2015 > 23 > 15 > 4489-4500

The anti-protozoal drug pentamidine is active against opportunistic Pneumocystis pneumonia, but in addition has several other biological targets, including the NMDA receptor (NR). Here we describe the inhibitory potencies of 76 pentamidine analogs at 2 binding sites of the NR, the channel binding site labeled with [³H]MK-801 and the [³H]ifenprodil binding site. Most analogs acted weaker at the ifenprodil...

article

Resolution of Mixed Site DNA Complexes with Dimer‐Forming Minor‐Groove Binders by Using Electrospray Ionization Mass Spectrometry: Compound Structure and DNA Sequence Effects

Sarah Laughlin, Siming Wang, Arvind Kumar, Abdelbasset A. Farahat, more

Chemistry – A European Journal > 21 > 14 > 5528 - 5539

Small‐molecule targeting of the DNA minor groove is a promising approach to modulate genomic processes necessary for normal cellular function. For instance, dicationic diamindines, a well‐known class of minor groove binding compounds, have been shown to inhibit interactions of transcription factors binding to genomic DNA. The applications of these compounds could be significantly expanded if we understand...

article

Synthesis and antiparasitic activity of new bis-arylimidamides: DB766 analogs modified in the terminal groups

Zong-ying Liu, Tanja Wenzler, Reto Brun, Xiaohua Zhu, more

European Journal of Medicinal Chemistry > 2014 > 83 > Complete > 167-173

Fifteen novel bis-arylimidamide derivatives with various 6-membered (7a–c) and 5-membered (7d–o) heterocyclic rings replacing the terminal pyridyl rings of the lead compound DB766{(2,5-bis[2-i-propoxy-4-(2-pyridylimino)aminophenylfuran]}, were prepared and evaluated versus Trypanosoma cruzi, Leishmania amazonensis, Trypanosoma brucei rhodesiense and Plasmodium falciparum. Compound 7a with pyrimidine...

article

Copper(I) 3-methylsalicylate, an efficient catalyst for N-arylation of heterocycles under moderate reaction conditions

Abdelbasset A. Farahat, David W. Boykin

Tetrahedron Letters > 2014 > 55 > 19 > 3049-3051

Copper(I) 3-methylsalicylate mediates N-arylation reactions of both aliphatic and aromatic heterocycles under moderate reaction conditions. Both electron rich and electron poor aryl bromides and a diverse set of N-heterocycles were allowed to react and gave N-arylation products in high yields which demonstrated the efficiency and utility of this catalyst.

article

A novel approach using electrospray ionization mass spectrometry to study competitive binding of small molecules with mixed DNA sequences

Sarah Laughlin, Siming Wang, Arvind Kumar, David W. Boykin, more

Analytical and Bioanalytical Chemistry > 2014 > 406 > 25 > 6441-6445

Minor groove binding compounds have been shown to induce changes in global DNA conformation, allosterically inhibiting DNA-protein interactions necessary for transcriptional processes. Many minor groove binders are specific for AT base pairs but have little preference over alternating AT or A-tract sequences. Few compounds, other than polyamides, show selectivity for mixed sequences with AT and GC...

article

CYP1A1 and CYP1B1‐Mediated Biotransformation of the Antitrypanosomal Methamidoxime Prodrug DB844 Forms Novel Metabolites Through Intramolecular Rearrangement

Wujian Ju, Sihyung Yang, John H. Ansede, Chad E. Stephens, more

Journal of Pharmaceutical Sciences > 103 > 1 > 337 - 349

DB844 (CPD‐594–12), N‐methoxy‐6‐{5‐[4‐(N‐methoxyamidino)phenyl]‐furan‐2‐yl}‐nicotinamidine, is an oral prodrug that has shown promising efficacy in both mouse and monkey models of second stage human African trypanosomiasis. However, gastrointestinal (GI) toxicity was observed with high doses in a vervet monkey safety study. In the current study, we compared the metabolism of DB844 by hepatic and extrahepatic...

article

Synthesis and antiprotozoal activity of dicationic 2,6-diphenylpyrazines and aza-analogues

Laixing Hu, Alpa Patel, Lavanya Bondada, Sihyung Yang, more

Bioorganic & Medicinal Chemistry > 2013 > 21 > 21 > 6732-6741

Dicationic 2,6-diphenylpyrazines, aza-analogues and prodrugs were synthesized; evaluated for DNA affinity, activity against Trypanosoma brucei rhodesiense (T. b. r.) and Plasmodium falciparum (P. f.) in vitro, efficacy in T. b. r. STIB900 acute and T. b. brucei GVR35 CNS mouse models. Most diamidines gave poly(dA-dT) ₂ ΔT _m values greater than pentamidine, IC ₅₀ values: T....

article

Synthesis and antiprotozoal activities of benzyl phenyl ether diamidine derivatives

Donald A. Patrick, Stanislav A. Bakunov, Svetlana M. Bakunova, Susan Kilgore Jones, more

European Journal of Medicinal Chemistry > 2013 > 67 > Complete > 310-324

Sixty-two cationic benzyl phenyl ether derivatives (36 amidines and 26 prodrugs) were prepared and assayed for activities in vitro and in vivo against Trypanosoma brucei rhodesiense (STIB900), and in vitro against Plasmodium falciparum (K1) and Leishmania donovani axenic amastigotes. 3-Amidinobenzyl 4-amidino-2-iodo-6-methoxyphenyl ether dihydrochloride (55, IC ₅₀ = 3.0 nM) and seven other...

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Search results for: David W. Boykin

Facile synthesis of benzobisimidazole and bibenzimidazole‐based bisnitriles as potential precursors for DNA minor groove binders

Small Sequence‐Sensitive Compounds for Specific Recognition of the G⋅C Base Pair in DNA Minor Groove

Hierarchical Nanotube Self‐Assembly of DNA Minor Groove‐Binding Ligand DB921 via Alkali Halide Triggering

Indole and Benzimidazole Bichalcophenes: Synthesis, DNA Binding and Antiparasitic Activity

Investigation of the electrostatic and hydration properties of DNA minor groove-binding by a heterocyclic diamidine by osmotic pressure

Inhibition of the myeloid master regulator PU.1 as a therapeutic strategy in acute myeloid leukemia

Exploration of DAPI analogues: Synthesis, antitrypanosomal activity, DNA binding and fluorescence properties

Antiprotozoal agents as water soluble singlet oxygen photosensitizers: Imidazo[1,2-a]pyridine and 5,6,7,8-tetrahydro-imidazo[1,2-a]pyridine derivatives

Synthesis, DNA binding and antitrypanosomal activity of benzimidazole analogues of DAPI

The Thiophene “Sigma‐Hole” as a Concept for Preorganized, Specific Recognition of G⋅C Base Pairs in the DNA Minor Groove

Synthesis and pharmacological evaluation of mono-arylimidamides as antileishmanial agents

Mixed up minor groove binders: Convincing A·T specific compounds to recognize a G·C base pair

Pentamidine analogs as inhibitors of [3H]MK-801 and [3H]ifenprodil binding to rat brain NMDA receptors

Resolution of Mixed Site DNA Complexes with Dimer‐Forming Minor‐Groove Binders by Using Electrospray Ionization Mass Spectrometry: Compound Structure and DNA Sequence Effects

Synthesis and antiparasitic activity of new bis-arylimidamides: DB766 analogs modified in the terminal groups

Copper(I) 3-methylsalicylate, an efficient catalyst for N-arylation of heterocycles under moderate reaction conditions

A novel approach using electrospray ionization mass spectrometry to study competitive binding of small molecules with mixed DNA sequences

CYP1A1 and CYP1B1‐Mediated Biotransformation of the Antitrypanosomal Methamidoxime Prodrug DB844 Forms Novel Metabolites Through Intramolecular Rearrangement

Synthesis and antiprotozoal activity of dicationic 2,6-diphenylpyrazines and aza-analogues

Synthesis and antiprotozoal activities of benzyl phenyl ether diamidine derivatives

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