The Crystal and Molecular Structure of 12, 13‐Dibromopseurotin

Bollinger³

et al. 1976

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111

The structure and absolute configuration of pseurotin (1), a new metabolite, isolated from culture filtrates of Pseudeurotium ovalis STOLK (Ascomycetes), has been shown to be 2‐[1′(S), 2′ (S)‐dihydroxhex‐3′‐ene‐yl]‐3‐methyl‐8(S)‐methoxy‐8‐benzoyl‐9(R)‐hydroxy‐(5S)‐1‐oxa‐7‐aza‐spiro[4.4]non‐2‐ene‐4, 6‐dione (1), by spectral data and chemical transformations, and by X‐ray analysis of its dibromo derivative 2 [1].

Section: 1mentioning

confidence: 99%

Pseurotin, a New Metabolite of Pseudeurotium ovalis STOLK Having an Unusual Hetero‐Spirocyclic System. (Preliminary Communication)

Bloch

Bollinger³

et al. 1976

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111

“…The following chemical transformations confirmed these conclusions and provided some indications concerning the nature of the unknown structural elements. The final proof of structure and the determination of the absolute configuration of pseurotin A (1) was adduced by the X-ray analysis of the 12,13dibromo derivative 2 [5].…”

mentioning

confidence: 99%

Isolation and Structure of Pseurotin A, a Microbial Metabolite of Pseudeurotium ovalis STOLK with an Unusual Heterospirocyclic System

Bloch

1981

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The structure and absolute configuration of pseurotin A, a new metabolite, isolated from culture filtrates of Pseudeurotium ovalis STOLK (Ascomycetes) has been shown to be (1'S,2'S, 5 S, 8 S. 9 R, 3'Z)-8-benzoyl-2 (l', 2-dihydroxy-3'-hexenyl)-9hydroxy-8-methoxy-3-methyl-1 -oxa-7-azaspiro (4.41non-2-ene-4.6-dione (1). 1.Introduction. -In 1968 Sigg et al. [ l ] isolated ovalicin from cultures of Pseudeurotium ovalis STOLK (Ascomycetes) as main metabolite and determined its structure. The biosynthesis [2] and the immuno-suppressive activity [3] of the new compound were studied. As reported in preliminary communications, we have found a second minor metabolite in the cultures of the same organism, named pseurotin A*). Its structure 1 was elucidated by spectral data and chemical transformations [4], and by X-ray analysis of its dibromo derivative 2 [5]. In this paper the details of this investigation are presented3). Spectral Data and Chemical Transformations of 1. -Pseurotin A (1) wasisolated from the culture broth of Pseudeurotium ovalis (strain S2269/F) by extraction with ethylene chloride. After final purification of the crude extracts by column chromatography on silica gel, the new metabolite was obtained from dichloromethane/hexane as colourless rhombic crystals of m.p. 162-163.5 and [ u ] g = -5+ 1" (c=0.5, methanol). The yield was ca. 30-35 mg/liter culture broth.Pseurotin A (I), a neutral substance, is readily soluble in polar solvents but much less soluble in non-polar solvents. Heating of solutions during a longer period of time caused decomposition of the compound. The molecular formula, C2*H2,NO,, was deduced from elemental analyses. In the mass spectrum the molecular ion is not observed. The highest peak at mlz 399 (M' -32) is due to the loss of methanol, as it is frequently observed with methyl ethers (especially with a-methoxy ketones) and methyl esters [6a] [6b]. The difference in mass of 32 I ) 2, 3,

“…With its y -1actam moiety, spirostaphylotrichin A (1) is structurally related to the tetramic acids, e.g. a -cyclopiazonic acid [2], erythroskyrine [3], and tenuazonic acid [4], to the cytochalasans [5], and to the pseurotins [6]. In these secondary metabolites, the biogenetic origin of the y-lactam ring is mixed, i.e.…”

Section: Studies On the Biosynthesis Of Spirostaphylotrichin Amentioning

confidence: 99%

“…(13.6 ml): 396 mg of 5 containing 37% of [2,3-13Cz]succinic acid. (6). Conversion of 5 to 6 by immobilized cells of E. coli and purification of 6 was rnn according to [I 31.…”

Section: [23-"c2]fumaric Acid (5)mentioning

confidence: 99%

Studies on the Biosynthesis of Spirostaphylotrichin A

Sandmeier

1989

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Incorporation of 14C‐labelled acetate and amino acids as well as of [1‐13C]‐, [2‐13C]‐, and [1,2‐13C2] acetate, L‐[methyl13C] methionine, [2,3‐13C2] succinate, and L‐[2,3‐13C2] aspartate into spirostaphylotrichin A (1) by Staphylotrichum coccosporum demonstrates that the building blocks of 1 are 5 units of acetate/malonate, 1 unit of methionine, and a C4‐dicarboxylic acid. The latter is most likely aspartate and derived from the citric‐acid cycle. Using [2‐13C, 2‐2H3] acetate as a precursor, the starter unit of the polyketide chain was identified.