The mechanisms of the gas-phase elimination kinetics of 1-chloro-3-methylbut-2-ene and 3-chloro-3-methylbut-1ene and their interconversion have been examined at MP2 and DFT levels of theory. These halide substrates yield isoprene and hydrogen chloride. The results MPW1PW91 calculations agree with the experimental kinetic parameters showing the elimination reaction occurs at greater rate for 1-c...

Phytochemical investigation of aerial parts of Helichrysum niveum (H. niveum) using different chromatographic methods including semi-preparative HPLC afforded three new (1-3) and six known (4-10) acylphloroglucinols alongside a known dialcohol triterpene (11). The structures of the isolated compounds were characterized accordingly as 1-benzoyl-3 (3-methylbut-2-enylacetate)-phloroglucinol (helin...

Exposure of beer to light results in the formation undesirable flavours or complete spoilage. Photo-damaged beerhas a specific, so-called skunky light-struck flavour (LSF). The compound responsible for LSF is 3-methylbut-2-ene-1-thiol (MBT). Riboflavin (RF) plays key role MBT. It absorbs blue part thespectrum and transfers excitation energy isohumulones. This process accompanied by decompositio...

A variety of group 4 metal catalytic systems (C2-symmetric {EBTHI}-, {SBI}-type zirconocene complexes (C2-1–4); C1-symmetric (C1-5–8) and Cs-symmetric (Cs-9) {Cp/Flu}-type zirconocene complexes; Cp*2ZrCl2 (Cp* 2-10)), half-metallocene complexes (CpTiCl3, HM-11), constrained-geometry (CGC-12) titanium catalysts) and post-metallocene catalysts (Dow’s ortho-metallated amido-pyridino hafnium comple...

The antimalarial activity of 22 xanthones against chloroquino-resistant strains of Plasmodium falciparum was evaluated. Natural caloxanthone C (1), demethylcalabaxanthone (2), calothwaitesixanthone (3), calozeyloxanthone (4), dombakinaxanthone (5), macluraxanthone (6), and 6-deoxy-gamma-mangostin (7) were isolated from Calophyllum caledonicum. 1,6-dihydroxyxanthone (8), pancixanthone A (9), iso...

Isoprenoid biosynthesis in plant plastids occurs via the 1-deoxy-d-xylulose 5-phosphate (DXP) pathway. We used tobacco rattle virus (TRV) to posttranscriptionally silence the expression of the last two enzymes of this pathway, the IspG-encoded (E)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (HDS) and the IspH-encoded isopentenyl/dimethylallyl diphosphate synthase (IDDS), as well as isopen...

This work describes the syntheses and antitumoral properties of five prenyl compounds from which antiproliferative activities were predicted by using the TOPS-MODE approach, a computational method for drug design. The syntheses of 2-(3-methylbut-2-enyloxy)acetophenone (2), 2-hydroxy-5-(3-methylbut-2-enyl)acetophenone (3), 2-hydroxy-3-(1,1-dimethylallyl)acetophenone (4), and 5-(3-methylbut-2-eny...