Hygrocins A and B, Naphthoquinone Macrolides from Streptomyces hygroscopicus

Abstract

Two new naphthoquinone macrolides, hygrocins A (1) and B (2), were isolated from the fermentation broth of Streptomyces hygroscopicus. Hygrocin A is not stable due to the presence of an active methylene group (C-22), which undergoes intramolecular aldol condensation with the quinone ring to yield a gamma-lactam derivative, 6. Its structural elucidation was achieved by chemical conversion to 3, an unusual diazomethane derivative, and confirmed by its alkaline hydrolysis product 4, hydrogenation derivative 5, and "degradation" product 6. The structure of hygrocin B was determined by combined chemical and spectroscopic methods.

PCR screening reveals considerable unexploited biosynthetic potential of ansamycins and a mysterious family of AHBA-containing natural products in actinomycetes

“…In addition, another new derivative of hygrocin A, which is an ester isomer of divergolide D isolated from a mangrove endophyte recently (Cai et al . ; Ding et al . ), was obtained from strain W112, an endophyte of Camptotheca acuminate .…”

“…2c) and a new derivative of hygrocin A. In addition, another new derivative of hygrocin A, which is an ester isomer of divergolide D isolated from a mangrove endophyte recently (Cai et al 2005;Ding et al 2011), was obtained from strain W112, an endophyte of Camptotheca acuminate. Another new ansamycin, 5, 21-cyclic derivative of ansalactam A, was identified from XZQH-4.…”

Divergolides A–D from a Mangrove Endophyte Reveal an Unparalleled Plasticity in ansa‐Macrolide Biosynthesis

“…The HMBC correlation (Scheme 2) between H11 (d = 5.19 ppm) and C5'' (d = 167.6 ppm) led to the connection of the aliphatic bridge to the aromatic nucleus, similar to a degradation product of hygrocin A. [25] The double bond at C3'' was proposed as Z because of the relative downfield shift of the signal for the allylic methyl group at C6'' (d = 21.6 ppm).…”

“…The 1D and 2D NMR data revealed that this metabolite represents a homologue of hygrocin B, an unusual metabolite isolated from Streptomyces hygroscopicus. [25] Compound 3 differs from hygrocin B in the unprecedented isobutenyl side chain at C12, the oxidative state of the aminonaphthoquinone, and the site of ester linkage.…”

Prediction of λmax of 1,4-naphthoquinone derivatives using ant colony optimization

“…Most NQ are easy to synthesize, stable in standard conditions, and show a wide range of colours depending on the substitution pattern [1][2][3]. In addition, NQ are of primary interest in several biological and medicinal applications [4][5][6][7][8][9][10]. For instance they make the core of K vitamin derivatives, of some antibacterial compounds, and of anti-malarial molecules as well.…”