Revised structure for the antibiotic pillaromycin A

A comprehensive review of glycosylated bacterial natural products

“…21] displaying atypical C-6- C -glycosylation. For the scope of this discussion, members have been divided into subclasses I–III based upon aglycon distinctions where the tetracyclic subclass II are primarily considered as biosynthetic precursors and subclass III (pillaromycin A) 341 also displays similarity to II .…”

“…Intriguingly, pillaromycin A, a potent anticancer cytotoxin from this family, has been noted to display lower overall toxicity. 341,345 …”

The structure and absolute configuration of viridicatumtoxin: 2'S-(2'α,7'aβ,11'aβ,12'β)-7',7'a,8',11',11'a,12'-hexahydro-5',6',7'a,10',11'a,12'-hexahydroxy-3'-methoxy-2,6,6-trimethyl-7',8'-dioxospiro[2-cyclohexene-1,2'(1'H)-cyclopenta[de]naphthacene]-9'-carboxamide methanolate

“…Steyn & Vleggaar (1976). The original X-ray data refined to an R factor of 0.059 which was considered too high for a reliable determination of absolute (1) 5730 (1) 5626 (2) C (2) 5759 (2) 2618 (3) 0(2) 6289 (2) 639 (3) N (2) 6398 (2) 3421 (4) C (3) 5431 (2) 1257 (3) 0(3) 5557 (2) -317 (3) C (4) 4897 (2) 1551 (3) C (4a) 4406 (1) 3324 (3) O(4a5 3539 (1) 3411 (2) C (5) 4036 (1) 3497 (3) 0(5) 3251 (1) 4790(2) C(5a) 4937 (15 3834 (3) C (6) 4832 (1) 3494 (3) C (6a) 5658 (2) 3870 (3) C (7) 5404 (1) 3493 (3) C (8) 6193 (2) 3661 (3) 0 (8) 5985 (i) 3156 (3) C (9) 7179 (2) 4317 (3) C (10) 7393 (2) 4756 (3) C (10a) 6630 (2) 4512 (3) O (10) 8350 (1) 5408 (3) C (11) 6753 (2) 4786 ( The first column indicates the heavier atom to which the H atom is attached.…”

“…The density 446 (6) of the crystals was not measured because loss of 435 (8) solvent of crystallization is fairly rapid. 411 (8) The previous work used space group A2 but a 540 (8) 446 (8) transformation to 12 produces more nearly orthogonal 536 (7) axes. Standard methods of least-squares refinement and 1532 (112) difference maps (Stewart, Kruger, Ammon, Dickinson 2090(135) & Hall, 1972 revealed all H atoms including some on O atoms and on the molecule of methanol which were indefinite in the earlier work.…”

Conformational studies on (+)-anatoxin-a and derivatives

“…From this search, seven compounds were extracted possessing the relevant structure suitable for comparative purposes [26][27][28][29][30][31]. Of these seven compounds, six possessed an s-trans configuration [26][27][28][29][30] while the seventh had an s-cis configuration [31]. The latter enone which was the enol form ofa 1,3-diketone, was locked in the s-cis conformation by an internal hydrogen bond and was thus excluded from this analysis.…”