GIAO NMR Calculations of Some Novel 8-Thio-Substituted 1,3,7-Trimethylxanthines: Comparison of Theoretical and Experimental<sup>1</sup>H Chemical Shifts

Stanchev, Stancho; Mitkov, Javor; Georgieva, Maya; Zlatkov, Alexander

doi:10.5504/bbeq.2012.0101

Cited by 4 publications

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References 13 publications

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“…Therefore, the relative configurations of C-3 and C-10 were 3 S *, 10 R *. To determine the relative configurations of C-5 and C-10 in 2, the 13 C chemical shifts calculations of (3 S* , 5 S* , 10 R* )-2 and (3 S* , 5 R* , 10 R* )-2 were calculated by a quantum chemical method at the B3LYP/6-311 + g (d,p) ( Stanchev et al, 2012 ; Marell et al, 2014 ) level (see Supporting Information). Comparison between experimental and calculated data suggested that the calculated 13 C chemical shifts of (3 S* , 5 S* , 10 R* )-2 were similar to the experimental one ( Figure 4 ; Supplementary Table S5 ) with a low mean absolute error value and a high DP4+ probability (100%) ( Figure 4 ) ( Grimblat et al, 2015 ).…”

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confidence: 99%

Two New Diterpenoids from Biscogniauxia sp. and Their Activities

et al. 2021

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Two new diterpenoids, including a seco-isopimarane type (1) and an abietane type (2), were isolated from Biscogniauxia sp. (71-10-1-1). Their structures, including absolute configurations, were elucidated by NMR spectroscopic analyses, X-ray crystallography, 13C chemical shifts calculations, and ECD calculations. This is the first report of diterpenoids from Biscogniauxia sp. Furthermore, short-term memory enhancement against Alzheimer’s disease (AD), anti-inflammatory, and cytotoxic activities of 1–2 were also evaluated. The results showed that compound 1 exhibited short-term memory enhancement activity against AD.

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Section: Resultsmentioning

confidence: 99%

Two New Diterpenoids from Biscogniauxia sp. and Their Activities

et al. 2021

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Diisoprenyl-cyclohexene/ane-Type Meroterpenoids from Biscogniauxia sp. and Their Anti-inflammatory Activities

et al. 2021

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A secondary metabolites investigation on Biscogniauxia sp. 71-10-1-1 was carried out, which led to the obtention of nine new diisoprenyl-cyclohexene/ane-type meroterpenoids (1–9) and two new isoprenylbenzoic acid-type meroterpeniods (10–11). The structures of these isolates were established on the basis of multispectroscopic analyses, ECD, and 13C chemical shifts calculations, and single-crystal X-ray diffraction. Among them, biscognin A (1) is the first diisoprenyl-cyclohexene-type meroterpenoid with a unique 2-isopropyl-6′-methyloctahydro-1′H-spiro[cyclopropane-1,2′-naphthalene] skeleton. Biscognienyne F (5) is the first diisoprenyl-cyclohexene-type meroterpenoid with a cyclic carbonate. The anti-inflammatory assays of the majority of compounds were evaluated, which exhibited that compounds 3 and 5 can obviously inhibit pro-inflammatory cytokines TNF-α and IL-6 productions. This is the first report for diisoprenyl-cyclohexene-type meroterpenoids with anti-inflammatory activity. Moreover, the possible biogenetic pathways of the majority of compounds (1–5) are proposed.

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Dimericbiscognienyne A: A Meroterpenoid Dimer from Biscogniauxia sp. with New Skeleton and Its Activity

et al. 2016

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Dimericbiscognienyne A (1), an unusual diisoprenyl-cyclohexene-type meroterpenoid dimer, was isolated from Biscogniauxia sp. together with three new monomeric diisoprenyl-cyclohexene-type meroterpenoids (2-4) and one new isoprenyl-benzoic acid-type meroterpenoid (5). All structures were determined by extensive NMR spectroscopic methods, quantum chemical calculations, chemical derivatization, and X-ray crystallography. The formation of 1 is related to a unique intermolecular redox coupling Diels-Alder adduct reaction. Their cytotoxicities and short-term memory enhancement activities against Alzheimer's disease were assessed.

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GIAO NMR Calculations of Some Novel 8-Thio-Substituted 1,3,7-Trimethylxanthines: Comparison of Theoretical and Experimental¹H Chemical Shifts

Cited by 4 publications

References 13 publications

Two New Diterpenoids from Biscogniauxia sp. and Their Activities

Two New Diterpenoids from Biscogniauxia sp. and Their Activities

Diisoprenyl-cyclohexene/ane-Type Meroterpenoids from Biscogniauxia sp. and Their Anti-inflammatory Activities

Dimericbiscognienyne A: A Meroterpenoid Dimer from Biscogniauxia sp. with New Skeleton and Its Activity

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GIAO NMR Calculations of Some Novel 8-Thio-Substituted 1,3,7-Trimethylxanthines: Comparison of Theoretical and Experimental1H Chemical Shifts

Cited by 4 publications

References 13 publications

Two New Diterpenoids from Biscogniauxia sp. and Their Activities

Two New Diterpenoids from Biscogniauxia sp. and Their Activities

Diisoprenyl-cyclohexene/ane-Type Meroterpenoids from Biscogniauxia sp. and Their Anti-inflammatory Activities

Dimericbiscognienyne A: A Meroterpenoid Dimer from Biscogniauxia sp. with New Skeleton and Its Activity

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GIAO NMR Calculations of Some Novel 8-Thio-Substituted 1,3,7-Trimethylxanthines: Comparison of Theoretical and Experimental¹H Chemical Shifts