{
  "abstract": "Visible light-driven E/Z photoisomerization is an attractive strategy for controlling reactivity and biological activity; however, targeted design of heterocyclic bioactive compounds requires a solid understanding of how substituent effects govern productive isomerization and competing photochemical pathways. Here, a series of 6-methyl-2-styryl-pyrimidine-4(3H)-one derivatives with previously reported antifungal and antimicrobial activity of E-isomers were studied by LED-NMR spectroscopy under visiblelight irradiation at 405-450 nm. Pronounced substituent-dependent differences were observed in the efficiency of E/Z photoisomerization, the stability of the corresponding Z-isomers, and the formation of [2 + 2] cycloaddition products. Derivatives bearing electron-donating groups showed particularly efficient photoresponse, with up to 95% conversion to the Z-isomer within 1-3 h at moderate irradiation power below 1 W. The resulting Z-isomers showed appreciable thermal stability, with half-lives ranging from several hours to several days. Quantum chemical calculations were used to rationalize the observed substituent effects and photoreaction outcomes. Among the computed descriptors, the oscillator strength f S₁ (E) was found to be the most informative. This descriptor represented the absorption-related contribution to photoconversion, and favorable transition intensities were calculated for derivatives bearing OMe-type donor-substituted phenyl groups attached to the vinylene fragment. These results establish substituted 6-methyl-2-styryl-pyrimidine-4(3H)-ones as a visible light-responsive scaffold in which photoconversion, Z-isomer stability, and competing cycloaddition can be tuned by substituent design.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemical and Biomolecular Engineering, National University of Singapore E5, Engineering Drive 4 Singapore 117585 Singapore.",
    "Scientific Technological Center of Organic and Pharmaceutical Chemistry 26 Azatutyan Street Yerevan 0014 Armenia astriksh@gmail.com."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Mikhail V Polynski",
      "orcid": "0000-0002-5559-0066"
    },
    {
      "affs": [
        1
      ],
      "name": "Zaruhi A Hovasyan",
      "orcid": "0000-0001-6698-7184"
    },
    {
      "affs": [
        1
      ],
      "name": "Arthur A Harutyunyan"
    },
    {
      "affs": [
        1
      ],
      "name": "Astghik A Shahkhatuni",
      "orcid": "0000-0003-1848-5256"
    },
    {
      "affs": [
        1
      ],
      "name": "Aleksan G Shahkhatuni",
      "orcid": "0000-0002-2506-1091"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/72ks4596fvaek.bib",
  "cited_by": 0,
  "doi": "10.1039/d6ra06890a",
  "fulltext_url": "https://europepmc.org/articles/PMC13647310",
  "id": "72ks4596fvaek",
  "issns": [
    "2046-2069"
  ],
  "landing_url": "https://europepmc.org/article/MED/42852146",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2505|Photochromic and Fluorescence Chemistry"
    ]
  ],
  "openalex": "W7220959529",
  "pdf_url": "https://europepmc.org/articles/PMC13647310?pdf=render",
  "pmcid": "PMC13647310",
  "pmid": "42852146",
  "published": "2026-10-08",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/72ks4596fvaek.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:02Z",
      "native_id": "MED:42852146",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42852146"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Photochromic and Fluorescence Chemistry",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Substituent-controlled visible light photoisomerization and cyclodimerization of styryl pyrimidinones.",
  "title_text": "Substituent-controlled visible light photoisomerization and cyclodimerization of styryl pyrimidinones.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:02Z",
  "url": "https://research.draconitic.com/paper/72ks4596fvaek",
  "venue": "RSC advances",
  "versions": []
}