1370658-06-2Relevant academic research and scientific papers
Acid-catalyzed Z-E isomerization of γ-alkylidenebutenolides: An experimental and DFT study
Varej?o, Jodieh O.S.,Barbosa, Luiz C.A.,Varej?o, Eduardo V.V.,Souza, Aline H.,Lage, Mateus R.,Carneiro, José W.M.
, p. 90 - 99 (2020/01/03)
The Z-E isomerization of γ-alkylidenebutenolide analogues to natural nostoclides and other natural butenolides was investigated using1H nuclear magnetic resonance (NMR) and high performance liquid chromatography (HPLC) data as well as density functional theory (DFT) calculations at the ωB97x-D/6-31G(d,p) level, including solvent effects with the polarizable continuum solvation approach. The experimental data supported the Z to E isomerization of γ-alkylidenebutenolides under acid catalysis. Newly prepared samples have predominantly Z configuration, which partially isomerizes to the E isomer under acidic conditions. Density functional theory studies corroborate the experimental findings. While neutral γ-alkylidenebutenolides are more stable in the Z form, protonation of the γ-lactone carbonyl group results in preferential stabilization of the E isomer.
Tailoring nostoclide structure to target the chloroplastic electron transport chain
Barbosa, Luiz C. A.,Varejao, Jodieh O. S.,Petrollino, Davide,Pinheiro, Patricia F.,Demuner, Antonio J.,Maltha, Celia R. A.,Forlani, Giuseppe
experimental part, p. 15 - 32 (2012/03/10)
Aiming to improve their effectiveness, three modifications were introduced into the structure of the natural phytotoxins nostoclides, leading to the synthesis of novel 3-benzyl-4-isopropyl-5- (arylmethylene)furan-2(5H)-ones, 3-benzyl-5-(furan-2-ylmethylene)furan-2(5H)-ones, and 3,4 dihalo-5- arylidenefuran-2(5H)-ones. All compounds were characterized by IR, 1H and 13C NMR, NOEDIF, COSY, HETCOR and MS spectrometry. Increasing the length of the molecule was found to reduce the ability to interfere with ferricyanide reduction by isolated chloroplasts. The addition of an isopropyl moiety into the heterocyclic ring, as in naturally-occurring nostoclides, did not influence the inhibitory potential. Also the replacement of the electron-drawing phenyl substituent with two halogen residues did not improve the resulting activity. However, both latter modifications influenced the interaction with the photosynthetic machinery. These analogues could therefore represent novel leads to be explored toward the development of new herbicides targeting the chloroplastic electron transport chain. ARKAT-USA, Inc.
