biological application of oligo-NSG. Here, we propose oligo(N-substituted alanine) (oligo-NSA) as a peptoid that forms a defined shape in water. The synthetic method established in this study enabled the first isolation and conformational study of optically pure oligo-NSA. Computational simulations, crystallographic studies and spectroscopic analysis demonstrated the well-defined extended shape of oligo-NSA
chemically and evaluated for hyphal branching-inducing activity in germinating spores of the arbuscular mycorrhizal fungus Gigaspora margarita. Hyphal branching activity was found to correlate with the degree of oxidation at C-19 methyl. Carlactone was only weakly active (100 ng/disc), whereas carlactonoic acid showed comparable activity to the natural canonical strigolactones such as strigol and sorgomol
Synthesis of 1,3-dioxin-4-ones and their use in synthesis. XX. (6S, 7S, 10R)- and (6R, 7S, 10R)-7-isopropyl-10-metyyl-4-oxo-1,5-dioxaspiro(5.5)undec-2-enes; Synthesis and their use in enantiomerically pure corey lactone analogue synthesis.
Two chiral spirocyclic dioxinones (S-5 and R-5) useful in teh so-called de Mayo reaction as alternatives to β-diketones (enones) have been synthesized; they not only act as formylacetates (inactive by themselves as enones) but also display remarkable diastereofacial selectivities in photoaddition to alkenes. The sythesis of these dioxinones is described, together with a practicl one-pot synthesis of enantiomerically pure (1S, 4R)-(+)-6-formyl-2-oxabicyclo[3.3.0]oct-6-en-3-one, the key intermediated of prostaglandin synthesis, from the (6S)-spirocyclic dioxinone (S-5).
The total synthesis of a racemic analog of putative helioporin C has been achieved. Starting from η6-5,6-dimethoxytetralin-Cr(CO)3 the target molecule was obtained in 8 steps in an overall yield of ca. 17%. The synthesis is based on the specific reactivity and stereochemistry of the arene-Cr(CO)3 substructure and involves highly regio- and diastereoselective benzylic deprotonation/alkylation steps
A novel reaction between benzothiazoles and diaroylacetylenes in the presence of Meldrum’s acid: ring expansion of benzothiazoles to functionalized 1,4-benzothiazines
A novel and efficient ringexpansion of benzothiazoles to functionalized 1,4-benzothiazines is described. The reactive 1:1 zwitterionic intermediates formed by addition of benzothiazoles to diaroylacetylenes were trapped with Meldrum’s acid under mild reaction conditions to produce 2-[2-hydroxy-2-aryl-2H-1,4-benzothiazin-3(4H)-yliden]-1-aryl-1-ethanones in excellent yields.
描述了新颖且有效的苯并噻唑环扩环为官能化的1,4-苯并噻嗪。在温和的反应条件下,将由苯并噻唑加成到二芳酰基乙炔中形成的反应性1:1两性离子中间体用Meldrum酸捕获,生成2- [2-羟基-2-芳基-2 H -1,4-苯并噻嗪-3(4 H) -yliden] -1-芳基-1-乙炔具有极好的收率。