Structure and tautomerism of tenuazonic acid – A synergetic computational and spectroscopic approach

Mycotoxins: Producing Fungi and Mechanisms of Phytotoxicity

“…For a better understanding of the structure of TA, the tautomerism as well as important equilibria (fast and slow), all reasonable tautomers and rotamers of TA have been subjected to quantum chemical calculations at an adequate level of theory. NMR spectra were calculated and compared to experimental data, finally leading to a synergetic computational and spectroscopic approach for structural investigations of TA and 3-acetyltetramic acids in general [152]. Its biological activity was first described by Shigeura and Gordon [153].…”

Assessment of the electronic structure and properties of trichothecene toxins using density functional theory

“…Type B trichothecenes possess a carbonyl in the R5 position and include compounds 1-10, and 29. This study also includes the type A trichothecene T-2 toxin and related compounds (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). T-2 toxin is associated with a variety of harmful effects, including alimentary toxic aleukia, and is a possible war agent [1].…”

“…These calculations describe the quantum nature of materials using an exchange-correlation functional, and have been highly successful in providing insight into structure based phenomena that are difficult to study experimentally [8,9]. Density functional studies have provided important information on toxin structures [10][11][12][13][14][15]; however, these methods have only been applied to a few trichothecene toxins. DFT studies at the B3LYP/6-31G(d,p) level of theory on the tautomers of deoxynivalenol and nivalenol gave additional structural insight into tautomer preferences and the interpretation of experimental IR and physical data [16,17].…”

“…The type B trichothecenes have natural charges of 0.54 at C8, −0.10 to −0.11 at C9, and −0.08 to −0.11 at C10, and this pattern has been associated with Michael acceptor reactions[48]. In contrast, T-2 toxin and other trichothecenes(11)(12)(13) with an ester or hydroxyl group(18)(19)(20) and 22) attached to the C8 position have charges of 0.09-0.10 at C8, 0.00 at C9, and −0.18 to −0.19 at C10. Unsubstituted trichothecenes at the C-8 position and possess the C9 C10 double bond (14-17, 21, 23-28, 31-35) have charges of −0.39 to −0.41 at C8, −0.02 to 0.03 at C9, and −0.19 to −0.25 at C10.…”

New PKS-NRPS tetramic acids and pyridinone from an Australian marine-derived fungus, Chaunopycnis sp.

“…collected near Moora Park, Shorncliffe, Queensland. Chemical fractionation of a broth cultivation of CMB-MF028 yielded the polyketide tetramic acid F-14329 (1) and three new analogues, chaunolidines A-C (2)(3)(4), as well as the new pyridinone chaunolidone A (5), and pyridoxatin (6). This report describes the production, isolation, characterization and structure elucidation of 1-6, including commentary on their biosynthesis and chemical interconversion, and spectroscopic and biological properties.…”