Derivatives of the tropane alkaloid convolvine with a series of iso(thio)cyanates were synthesized. The structures of the synthesized compounds were proved using IR and NMR spectroscopic data and X-ray crystal structure analyses (for 3b and 3c).
Derivatives of the tropane alkaloid convolvine with a series of iso(thio)cyanates were synthesized. The structures of the synthesized compounds were proved using IR and NMR spectroscopic data and X-ray crystal structure analyses (for 3b and 3c).
Two new aromatic sesquiterpenes, nicosesquites C and D (1 and 2), as well as five known sesquiterpenes (3–7), were isolated from tobacco flower extract. Their structures were determined mainly by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were tested for their antibacterial activity against five pathogenic strains (Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Bacillus subtilis, and Proteus spp.). The results revealed that both compounds showed high antibacterial activity with bacteriostatic diameters in the range of 18.2 ± 1.4~25.8 ± 2.2 mm, respectively. In addition, compounds 1 and 2 also have a weak resin-like aroma, and they have potential value for use as an essence for cigarettes.
In this study, two new (1 and 2), together with five known (3–4) naphthoquinones were isolated from the Nicotiana tabacum-derived endophytic Fusarium solani. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. All compounds were evaluated for their antibacterial activities against five nitrosobacteria strains (Nitrosomonas communis, Nitrosomonas nitrosa, Nitrosospira multiformis, Nitrobacter winogradskyi, and Nitrospira inopinata). Interestingly, compounds 1–7 exhibited notable antibacterial activity with the bacteriostatic diamater in the range of 3.2 ± 1.7~25.4 ± 2.3 mm against five nitrosobacteria strains, and most of the bacteriostatic diamaters were higher than that of positive control. Due to the nitrosobacteria having the ability to convert nitrogen components into nitrosamines in tobacco, and then convert them into tobacco specific nitrosamines (TSNAs), the above compounds have the potential to reduce TSNAs in tobacco by inhibiting nitrosobacteria during the fermentation process of tobacco leaves.
A new catechol, 4-diazenylcatechol (1) and ten known compounds were isolated from the stems of pumpkin (Cucurbita pepo L. (Cucurbitaceae)). The structure of this new catechol was elucidated by chemical and physical evidence.
From the leaves of Sibiraea angustata, sibirmonoside B (1), coniferin (2), syringin (3), were isolated. Sibirmonoside B (1) was a new one, and other known compounds were isolated from the genus of Sibiraea for the first time. Their structures were elucidated on the basis of chemical and spectroscopic evidence and comparisons with data from the literature of related compounds.
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