Lowdenic acid (1), a new antifungal metabolite with an unusual structure and a mixed biogenetic origin, has been obtained from nonsporulating cultures of a previously undescribed Verticillium sp. (MYC-406 = NRRL 29280) that was isolated as a colonist of polypore basidiomata. The gross structure of 1 was proposed by analysis of NMR data and confirmed by X-ray diffraction analysis, which enabled assignment of relative stereochemistry. Compound 1 occurs as an equilibrium E/Z mixture. The known antifungal metabolite canescin A (2) was also isolated.

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Five new phenopicolinic acid analogues (1-5) have been isolated from solid-substrate fermentation cultures of Verticillium lecanii. The most abundant component (vertilecanin A; 1) displays antiinsectan activity against Helicoverpa zea. These compounds were obtained by chromatographic fractionation of the EtOAc culture extract and identified by analysis of NMR and MS data. The known fungal metabolites 2-decenedioic acid and 10-hydroxy-8-decenoic acid were also isolated from these cultures.

To address third- and fourth-year chemistry students’ difficulties with the challenge of interpreting 1H NMR spectra, a problem solving-cooperative learning technique was incorporated in a Spectra of Organic Compounds course. Using this approach helped students deepen their understanding of the basics of 1H NMR spectroscopy and develop abilities to think skillfully and apply these skills to elucidate structures from spectra more consistently. The multistep method allowed for increased instructor feedback, as each step was evaluated by grading students’ work. Assessment of the overall method was performed using two evaluation tools. A comparison of students’ cumulative grades for three consecutive years with and without using the approach was made, and the resulting statistical data demonstrate an improvement in student performance for the treatment groups relative to the control group. The second tool was the survey data. Analyzing students’ feedback in the last step of the method closely mirrors how students’ acceptance of the proposed approach was meaningful, which was also supported by the positive comments of students. All student work is used with permission.

The chemical investigation of an Indonesian specimen of Theonella swinhoei afforded four aurantosides, one of which, aurantoside J (5), is a new compound. The structure of this metabolite, exhibiting the unprecedented N-α-glycosidic linkage between the pentose and the tetramate units, has been determined through detailed spectroscopic analysis. The four obtained aurantosides have been tested against five fungal strains (four Candida and one Fusarium) responsible of invasive infections in immuno-compromised patients. The non-cytotoxic aurantoside I (4) was the single compound to show an excellent potency against all the tested strains, thus providing valuable insights about the antifungal potential of this class of compounds and the structure-activity relationships.

Malettinins B-D (2-4), three new antimicrobial polyketide-derived metabolites related to the previously reported malettinin A (1), have been obtained from nonsporulating cultures of an isolate of Mycelia sterilia MYC-155 (= NRRL 29110) collected from colonies of Hypoxylon stromata. Malettinins B (2) and C (3) are partially reduced analogues of malettinin A and were identified by analysis of NMR and MS data. Malettinin D (4) is biogenetically similar, but possesses a new ring system, and the structure of 4 was established by single-crystal X-ray diffraction analysis.

The chlorinated polyene aurantoic acid (1) and the 4-methylene sterol dehydroconicasterol (2) were isolated from the Indonesian sponge Theonella swinhoei, and their structures were elucidated by interpretation of spectroscopic data. Aurantoic acid is a unique member in the class of naturally occurring conjugated polyene derivatives, while dehydroconicasterol is the likely biogenetic precursor of the major Theonella 4-methylene sterols.

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