Marasmic acid

Problem Given the stereochemistry shown on p 176 of the starting materials ior the synthesis of Woodward s marasmic acid intermediate (3), what will be the stereochemistry of the product ... 

Photoelimination of nitrogen from 1-pyrazolines has also been employed in the synthesis of tricyclo[3.2.1.02,4]oct-6-ene,338 prismane,339 quadri-cyclane,340 snoutene ,341 and marasmic acid.342 The trimethylenemethanes 414 have been prepared by photolysis of azoalkanes 415 and characterized spectroscopically.343 Dimerization and cycloaddition to alkenes of these biradicals have been reported.344... 

The key intermediate in Tobe et al. s synthesis of (+)-marasmic acid (27), 1-oxa-spirohexane (26), was accessed via a photocycloaddition between enone 24 and 1 (Scheme 19.6) [8], The photocydoadduct 25 was obtained in 73% yield with the desired isomer consisting of 91% of the material. The structure of the minor product obtained from this cycloaddition was not confirmed. Reduction of the carbonyl group of 25 and epoxidation of the exocyclic double bond gave 26. An acid-catalyzed rearrangement of 26 afforded the core structure of marasmic acid and was subsequently taken on to complete the synthesis of this natural product. 

The first total synthesis of ( )-marasmic acid (212) (c/. synthesis of isomarasmic acid, Vol. 1. p. 81) has been accomplished by the reaction sequence shown in... 

X-Ray analyses of two heavy-atom derivatives of illudol (203) and marasmic acid (204) have confirmed the ds-fused hydrindane skeletons in each and this fact is in accord with the stereochemistry of the hypothetical precursor (205) derivable from humulene. Matsumoto and co-workers have now completed... 

Marasmic acid (13) was isolated from the basidiomycete Marasmium conigenus (mold). This compound possesses potent antibacterial activity against Staphylococcus aureus and E. coli although no mechanism of action has been established. 

This reaction has been successfully applied to the synthesis of the basic skeleton of the ses-quiterpene marasmic acid 6 starting from a suitable tricyclic epoxide 4. ... 

Full reports on the syntheses of methyl isomarasmate (382) and the naturally occurring marasmic acid (383) have appeared.187-188 A second imaginative synthesis of marasmic acid (383) has also been reported (Scheme 48).189 Once again the power of the intramolecular Diels-Alder reaction has played a pivotal role in... 

Marasmic acid (5.83)— first isolated from Marasmius conigenus in 1949— is a toxic metabolite that possesses anti-bacterial and mutagenic properties. Its structure was established in 1966 by a combination of chemical and spectroscopic studies and confirmed by X-ray analysis. 

A new sesquiterpenoid skeleton has been discovered in the form of lactarorufin A (193) isolated from Lactarius rufus. At the present time only the relative stereochemistry of the four asymmetric centres is known and it has been suggested that its biogenesis can be considered in terms of opening of the cyclopropyl-carbinyl cation (194) which has previously been proposed in the marasmic acid biogenesis. In another study of Lactarius species, Magnusson et have... 

Sesquiterpenoids derived biosynthetically from hu-mulene and isolated from the fruit bodies and cultures of basidiomycetes, the best known examples are iso-velleral, marasmic acid, and stearoylvelutinal. Ma-rasmenes are sesquiterpenes with the drimane skeleton. 

Cradwick, P.D., and G.A. Sim Crystallographic Determinations of Partial Stereochemistries of the Sesquiterpenoids Illudol and Marasmic Acid. J. Chem. Soc., Chem. Commun., 431 (1971). 

Similarly, high toxicity mihtates against any useful therapeutic application of the anti-tumour properties [45, 487] of the unusually constituted sesquiter-penoid, illudin S (LXV) [47] (syn. lampterol [46]), just as the marked activity against Staphylococcus aureus [488] displayed by marasmic acid (LXVI) [489,... 

Illudol (67) and marasmic acid (68) are both examples of fungal metabolites which are thought to arise from a humulene-like precursor. Humulene itself is conformationally mobile in solution, but as a solid complex with silver nitrate it has a fixed conformation (69) which has been invoked to... 

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