Synthesis and Investigation of Tricyclic Isoquinoline Derivatives as Antibacterial Agents

Isoquinoline derivatives exhibit a range of biological properties, including antibacterial activity, and are thus attractive as a scaffold for developing broad-spectrum antibacterial compounds. A series of six isoquinoline-based compounds were synthesized using the reaction of 6,7-dimethoxy-1-methyl...

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Main Authors: Matthew J. A. Phillips, Alison T. Ung, Elizabeth J. Harry, Jason Ashmore, Andrew M. McDonagh
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:BioChem
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Online Access:https://www.mdpi.com/2673-6411/5/1/1
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author Matthew J. A. Phillips
Alison T. Ung
Elizabeth J. Harry
Jason Ashmore
Andrew M. McDonagh
author_facet Matthew J. A. Phillips
Alison T. Ung
Elizabeth J. Harry
Jason Ashmore
Andrew M. McDonagh
author_sort Matthew J. A. Phillips
collection DOAJ
description Isoquinoline derivatives exhibit a range of biological properties, including antibacterial activity, and are thus attractive as a scaffold for developing broad-spectrum antibacterial compounds. A series of six isoquinoline-based compounds were synthesized using the reaction of 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinoline with dimethyl acetylenedicarboxylate (DMAD) to provide the tricyclic (2Z)-[2-oxo-5,6-dihydropyrrolo[2,1,a]isoquinolin-3-ylidene]-2-ethanoate. The [2 + 3] cycloaddition of DMAD with C-6 and C-7 substituted 1-methyl-3,4-dihydroisoquinolines proceeded using aryl ethers or unsubstituted compounds, but not with amine, amide or nitro moieties at the C-7 position. Compounds <b>8d</b> and <b>8f</b> were found to have antibacterial properties against some Gram-positive pathogens (<i>Staphylococcus aureus</i>—<b>8d</b> = 16 µg/mL, <b>8f</b> = 32 µg/mL; <i>Streptococcus pneumoniae—</i><b>8f</b> = 32 µg/mL; and <i>Enterococcus faecium—</i><b>8d</b> = 128 µg/mL, <b>8f</b> = 64 µg/mL). Evaluation of their cytotoxic properties against mammalian cell lines revealed some cytotoxic effects (<b>8b</b> and <b>8d</b>, 125 µM, 24 h, HEp-2 cells) and (<b>8a</b>, <b>8b</b>, <b>8d</b> = 125 µM, <b>8f</b> = 62.5 µM, 24 h, McCoy B cells), suggesting limitations in their antibacterial applications without further development.
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spelling doaj-art-3791ba7b065e42b8885151cbfb53bbf32025-08-20T02:11:22ZengMDPI AGBioChem2673-64112024-12-0151110.3390/biochem5010001Synthesis and Investigation of Tricyclic Isoquinoline Derivatives as Antibacterial AgentsMatthew J. A. Phillips0Alison T. Ung1Elizabeth J. Harry2Jason Ashmore3Andrew M. McDonagh4School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, AustraliaSchool of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, AustraliaAustralian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, AustraliaSchool of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, AustraliaSchool of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, AustraliaIsoquinoline derivatives exhibit a range of biological properties, including antibacterial activity, and are thus attractive as a scaffold for developing broad-spectrum antibacterial compounds. A series of six isoquinoline-based compounds were synthesized using the reaction of 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinoline with dimethyl acetylenedicarboxylate (DMAD) to provide the tricyclic (2Z)-[2-oxo-5,6-dihydropyrrolo[2,1,a]isoquinolin-3-ylidene]-2-ethanoate. The [2 + 3] cycloaddition of DMAD with C-6 and C-7 substituted 1-methyl-3,4-dihydroisoquinolines proceeded using aryl ethers or unsubstituted compounds, but not with amine, amide or nitro moieties at the C-7 position. Compounds <b>8d</b> and <b>8f</b> were found to have antibacterial properties against some Gram-positive pathogens (<i>Staphylococcus aureus</i>—<b>8d</b> = 16 µg/mL, <b>8f</b> = 32 µg/mL; <i>Streptococcus pneumoniae—</i><b>8f</b> = 32 µg/mL; and <i>Enterococcus faecium—</i><b>8d</b> = 128 µg/mL, <b>8f</b> = 64 µg/mL). Evaluation of their cytotoxic properties against mammalian cell lines revealed some cytotoxic effects (<b>8b</b> and <b>8d</b>, 125 µM, 24 h, HEp-2 cells) and (<b>8a</b>, <b>8b</b>, <b>8d</b> = 125 µM, <b>8f</b> = 62.5 µM, 24 h, McCoy B cells), suggesting limitations in their antibacterial applications without further development.https://www.mdpi.com/2673-6411/5/1/1antibacterialisoquinoline3,4-dihydroisoquinolinecytotoxicity
spellingShingle Matthew J. A. Phillips
Alison T. Ung
Elizabeth J. Harry
Jason Ashmore
Andrew M. McDonagh
Synthesis and Investigation of Tricyclic Isoquinoline Derivatives as Antibacterial Agents
BioChem
antibacterial
isoquinoline
3,4-dihydroisoquinoline
cytotoxicity
title Synthesis and Investigation of Tricyclic Isoquinoline Derivatives as Antibacterial Agents
title_full Synthesis and Investigation of Tricyclic Isoquinoline Derivatives as Antibacterial Agents
title_fullStr Synthesis and Investigation of Tricyclic Isoquinoline Derivatives as Antibacterial Agents
title_full_unstemmed Synthesis and Investigation of Tricyclic Isoquinoline Derivatives as Antibacterial Agents
title_short Synthesis and Investigation of Tricyclic Isoquinoline Derivatives as Antibacterial Agents
title_sort synthesis and investigation of tricyclic isoquinoline derivatives as antibacterial agents
topic antibacterial
isoquinoline
3,4-dihydroisoquinoline
cytotoxicity
url https://www.mdpi.com/2673-6411/5/1/1
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