Yaequinolones, New Insecticidal Antibiotics Produced by Penicillium sp. FKI-2140

Abstract

New nine insecticidal antibiotics designated yaequinolones were isolated from the culture broth of the fungal strain Penicillium sp. FKI-2140 by solvent extraction, centrifugal partition chromatography and HPLC. Yaequinolones showed growth inhibitory activity against brine shrimp (Artemia salina). Among them, yaequinolone F has the most potent activity with MIC value of 0.19 mg/ml.

Oxidative Cyclization in Natural Product Biosynthesis

“…504,505 732 was initially thought of as an intermediate towards the formation of penigequinolone and aspoquinolone. Subsequent feeding and biochemical studies, however, demonstrated this is a shunt and co-metabolite.…”

A Catalytic Asymmetric Ring‐Expansion Reaction of Isatins and α‐Alkyl‐α‐Diazoesters: Highly Efficient Synthesis of Functionalized 2‐Quinolone Derivatives

“…[5] However, the catalytic reactions developed by these research groups involved the ring expansion of symmetric aliphatic cyclic ketones through 1,2-alkyl migration. [14] Efficient asymmetric approaches to incorporate this important molecular scaffold are limited, [15] as are the formations of chiral quaternary centers. To the best of our knowledge, asymmetric ring expansion of prochiral cyclic carbonyl compounds, which usually suffer from complicated regiochemical problems, [1a, 2c] has not been documented to date.…”

“…In this reaction multiple products are possible because of competitive 1,2-aryl migration and 1,2-carbonyl migration reaction pathways (Scheme 1). [14] Efficient asymmetric approaches to incorporate this important molecular scaffold are limited, [15] as are the formations of chiral quaternary centers. In a continuation of our research with diazo compounds, [7] we report herein a highly enantioselective ring-expansion reaction of isatins and a-alkyl-a-diazoesters involving 1,2-aryl migration.…”

“…[14] The absolute stereochemistry of the secondary hydroxy group of 5 was determined to be R by using the modified Mosher-ester analysis. The reaction of isatin 2 a was carried out on a gram scale (1.19 g, 5.0 mmol) to show the scalability of this method and gave the product 3 a in 89 % yield and 99 % ee (Scheme 4 a).…”

“…[8] Quinolone scaffolds, [9] particularly functionalized 2-quinolones that contain a chiral quaternary center at C4, are common in natural products and medicinal molecules, such as the Melodinus alkaloids (scandine, [10] meloscine, [11] and meloscandonine), [12] melicodenine G, [13] and yaequinolone A1. [14] Efficient asymmetric approaches to incorporate this important molecular scaffold are limited, [15] as are the formations of chiral quaternary centers. [16] The asymmetric ring-expansion reaction of isatins and a-substituted a-diazoesters would be a straightforward method for preparing this quinolone compounds.…”