5 article(s) from Urabe, Daisuke
Graphical Abstract
Figure 1: Structures of nomimicins A–D (4 and 1–3).
Figure 2: COSY and key HMBC correlations for 1.
Figure 3: Relative configuration of 1 determined by ROESY analysis.
Figure 4: Experimental ECD spectra of 1, 2, and 4 and calculated ECD spectrum of 4.
Figure 5: Four tautomers 4a–4d of the tetronic acid moiety of 4 and calculated ECD spectra.
Figure 6: COSY and key HMBC correlations for 3.
Figure 7: Relative configuration of 3 determined by NOESY analysis.
Graphical Abstract
Figure 1: Structure of the nocarimidazoles 1–4 and the bulbimidazoles 5–7.
Figure 2: COSY and key HMBC correlations for 1 and 2.
Scheme 1: Synthesis of the model compounds 8 and 9.
Figure 3: 1JC,H coupling constant for the imidazole ring of the natural products 1 and 5 and the model compou...
Figure 4: Determination of the absolute configuration of 1 (a), 4 (b), and 5 (c) by the Ohrui–Akasaka method.
Figure 5: Stereochemical diversity of the anteiso-chain chirality in microbial metabolites.
Graphical Abstract
Figure 1: Structures of pseudosporamide (1) and pseudosporamicins A–C (2–4).
Figure 2: COSY, key HMBC and ROESY correlations of pseudosporamide (1).
Figure 3: 1H NMR ΔδS−R values for PGME amides 5a and 5b obtained from compound 1.
Figure 4: The opposite axial chirality around the biaryl C-6–C-7'' bond influenced by the C-2 configuration i...
Figure 5: The experimental and calculated ECD spectra in MeCN.
Figure 6: COSY, key HMBC and NOESY correlations of compound 2.
Figure 7: NOESY correlations for the spiroacetal moiety of compound 2.
Figure 8: Selected examples of oligomycin-class metabolites from actinomycetes.
Graphical Abstract
Figure 1: Structures of compounds 1–7.
Figure 2: Key HMBC correlations and two possible structures (a and b) for karimunone A (1).
Figure 3: Key HMBC correlations for karimunone B (2).
Graphical Abstract
Scheme 1: Structure of ryanodine and the Diels–Alder reactions for construction of the potential intermediate...
Scheme 2: Asymmetric synthesis of 7 and determination of the absolute configuration at C4 of 15 by the modifi...
Scheme 3: Generation of 17 through the 6π-electrocyclic reaction and the Diels–Alder reaction.
Scheme 4: Rationale of the stereoselectivity of the Diels–Alder reaction.
Scheme 5: Synthesis of C2-symmetric 1.