Synthesis of 3-Alkylcatechols via Intramolecular Cyclization
作者:Tetsuo Miyakoshi、Hiroyasu Togashi
DOI:10.1055/s-1990-26889
日期:——
The intramolecular cyclization of 2-alkanoyl-2,5-dimethoxytetrahydrofurans 4 with aqueous acid is described. 3-Alkylcatechols 7 were prepared in generally good yields by boiling the dioxane solution of compounds 4 in the presence of 1M hydrochloric acid. In addition, 4,5-dioxoalkanals 6 were obtained in good to high yields when the dioxane solution of compounds 4 was treated with 0.1 M hydrochloric acid.
Synthesis and Biological Evaluation of Highly Potent Fungicidal
<i>Deoxy</i>
‐Hygrophorones
作者:Toni Ditfe、Eileen Bette、Haider N. Sultani、Alexander Otto、Ludger A. Wessjohann、Norbert Arnold、Bernhard Westermann
DOI:10.1002/ejoc.202100729
日期:2021.7.22
Although stripped from hydroxyl-groups, deoxygenated hygrophorones remain highly active against severe phytopathogens. The synthesis to these natural product congeners is achieved in rearrangement sequences, with an optimized deprotection strategy avoiding retro-aldol reactions. The activities are comparable to fungicides used in agriculture.
Polydora websterii, a harmful lugworm that has serious adverse effects on pearl oyster cultivation, was inhibited by a marine diterpene, crenulacetal C, isolated from the brown alga Dictyota dichotoma, Based on consideration of the activity-structure relationship, several synthetic compounds having an aromatic moiety with a hydroxyalkyl chain were prepared. Bioassay using larvae of Polydora websterii as well as pearl oysters (Pinctada fucata martensii) suggested that 1-(2-furyl)-1-nonanol was the most promising inhibitor.
The Solvent Dependence of the Diastereoselective Hydrogenation of 2- and 2,5-Substituted Furylcarbinols on a Raney Nickel Contact
作者:Andreas Gypser、Hans-Dieter Scharf
DOI:10.1055/s-1996-4210
日期:1996.3
The diastereoselective hydrogenation of 2,5-disubstituted furans on a Raney nickel contact provides an easy access to tetrahydrofurylcarbinols 3 and 4. Due to the alcohol used as solvent it is possible to influence the direction of the stereoselection process (erythro vs. threo). The highest diastereoselectivities reached till now are in the range of 70%.
2, 5‐Dialkylfuran and tetrahydrofuran compounds as structural elements of Annonaceae acetogenins like Asitrocinwere synthesized starting from furfural by Grignard reactions, lithiation of the furan ring and addition of aliphatic aldehydes. Hydrogenation of the furan rings over Pd‐catalyst gave the corresponding tetrahydrofurans. All resulting compounds showed no or rather less antimicrobial activity