Synthese und Bestimmung der absoluten Konfiguration von Pyrenophorin und Vermiculin

Abstract

Zwei makrocyclische Naturstoffe, das Fungicid Pyrenophorin (1) und das Antibioticum Vermiculin (2), wurden jetzt unter Anwendung der Dithian‐Methode in optisch aktiver Form dargestellt. Die Synthese beweist zugleich, daß natürliches (1) (R,R)‐ und natürliches (2) (S,S)‐konfiguriert ist.

Secondary Metabolites Isolated from an Endophytic Phoma sp. – Absolute Configuration of Tetrahydropyrenophorol Using the Solid‐State TDDFT CD Methodology

“…In the IR spectrum, the peaks at 3325 and 1716 cm -1 indicated the presence of hydroxy groups and a carbonyl group, respectively. Analysis of the 1 H-, 13 C-, and 2D ( 1 H-1 H-COSY and 1 H-13 C-HETCOR) NMR and mass spectroscopic data and comparison with literature values revealed the identity with pyrenophorol (1) (Figure 1). The similar specific optical rotation in chloroform of our product with the reported value ([α] D = -14.9) [2] indicated the same absolute configuration for the two samples.…”

“…124-127°C and had much higher levorotatory specific optical rotation ([α] D = -68) than 1. The EIMS [M + H + /2] with m/z = 159 for C 8 H 14 O 3 showed half of the symmetrical dimeric molecule as did the NMR spectra with 8 signals in the 13 C NMR and 14 proton signals in the 1 H NMR spectra. The IR spectrum showed absorption for the hydroxy group at 3418 cm -1 and carbonyl carbon at 1732 cm -1 .…”

Diversity of Antimicrobial Pyrenophorol Derivatives from an Endophytic Fungus, Phoma sp.

“…The isolation of twelve different derivatives by isolation or chemical transformations and comparison of their data enabled the complete assignment of all signals in the 1 H and 13 C NMR spectra of the pyrenophorol family that have not previously been completely reported. [20][21][22][23][24][36][37][38][39][40][41][42] Experimental Section General Experimental Procedures: For microbiological methods and culture conditions, see refs.…”

“….1 mg, 83 %). [20][21][22][23][36][37][38][39][40][41][42] Synthesis of 4,4Ј-Diacetylpyrenophorol (11) by Acetylation of Pyrenophorol (1): To a solution of 1 (9.0 mg) in dry pyridine (0.5 mL) were added 2 drops of Ac 2 O. The mixture was kept at room temperature for 16 h to afford, after usual workup, 11 [4] quantitatively ( …”

Logic of organic chemistry

“…This was achieved by the extensive use of ''umpoled'' dithianes by the Seebach group. During the total synthesis of vermiculine a 1,6-difunctional synthons was needed [49].…”