Mevalonolactone

On standing in dilute aqueous acid compound A is smoothly converted to mevalonolactone... 

Finally, natural (i )-(-)-mevalonolactone, a key intermediate from a broad spectrum of cellular biological processes and their regulation, was synthesised via eight steps in 55% overall yield and > 99% ee (Scheme 19). In the key step, the aforementioned enantioconvergent chemoenzymatic deracemization route was applied. Thus, 2-methyl-2-benzyl-oxirane ( )-2 g was deracemized on a large scale (10 g) using lyophilized cells of Nocardia EHl and sulfuric... 

Phomopsis sp. strain endophytes of the medicinal plant Erythrina crista-galli continue to yield novel compounds (Table 1). New phenyl-propane, pyronol, benzoic acid, phenylpyran, macrocyclic, and alkene compounds were discovered, as well as the known compounds clavatol, 4-hydroxymellein, mellein, mevalonolactone, mevinic acid, nectriapyrone, phomol, scytalone, and tyrosol. The new compounds were phomopy-ronol (101), 3-phenylpropane-l,2-diol (102), 4-(2,3-dihydroxypropoxy) benzoic acid (103), 2-(hydroxymethyl)-3-propylphenol (104), 2-... 

HLADH oxidation of 3-methylpentane-l,3,5-triol yields, after silver oxide oxidation, (35)-(-l-)-mevalonolactone of 14% optical purity/" The synthesis of [4,5- C2]MVA using known procedures was omitted from last year s Report, " " and another synthesis of ( )-mevalonolactone has been reported. " ... 

In view of the importance of mevalonate in the biosynthesis of terpenes and steroids, it is not surprising that numerous syntheses of mevalonolactone are available. These are briefly itemized in the detailed procedure for the synthesis of (i ,S)-mevalonolactone labelled at C-2 with 13C (Scheme 215) (81OS(60)92>. 

Metronidazole — see also Imidazole, l-(2-hydroxy-ethyl)-2-methyl-5-nitro-antiprotozoal activity, 1, 180 veterinary use, 1, 208 mode of action, 1, 208 Metyrapol metabolism, 1, 234 Metyrapone metabolism, 1, 234 Mevaloladone synthesis, 1, 490 Mevalonolactone synthesis, 3, 846 MG18755... 

Lakner FJ, Hager LP (1996) Chloroperoxidase as Enantioselective Epoxidation Catalyst An Efficient Synthesis of (R)-(-)-Mevalonolactone. J Org Chem 61 3923... 

CPO has been used occasionally in complex syntheses. An important application of CPO as an enantioselective epoxidation catalyst is the efficient synthesis of (R)-2-mevalonolactone (Scheme 2.26a) [270]. A survey of the literature revealed that the previous methods required many steps to produce the lactone, in low overall yield, with moderate ee, in addition to expensive starting materials. Meanwhile, a retro-synthetic analysis starting with an appropriately functionalized epoxide provided confidence that CPO could rescue the situation if used in the key stereogenic step. Another completed synthesis is depicted in Scheme 2.26b. Again, the epoxide is generated in high yield with conversion to (R)-dimethyl-2-methylaziridine-l,2-dicarboxylate, which may serve as a synthon for P-methylamino acids [283],... 

Scheme 2.26 CPO-catalyzed epoxidations as key steps in the syntheses of (R)-2-mevalonolactone (a) and (R)-dimethyl-2-methylaziridine-l,2-dicarboxylate (b).

The dihydroxy acid that is formed in this step cyclizes to the S-lactone mevalonolactone. 

M. Fetizon, M. Golfier, and J. M. Louis, Highly selective oxidations of diols by silver carbonate, Chem. Commun., (1969) 1102 A new synthesis of lactones application to ( )-mevalonolactone, ibid., (1969) 1118-1119. 

The typical secondary metabolites of soft corals are diterpenoids, although some species also produce sesquiterpenoids. The sesquiterpene portion of furoquinol (Structure 2.102) is labeled by [2-3H]mevalonolactone in Sinularia capillosa,m while Heteroxenia sp. converts acetate and meva-lonate into cubebol (Structure 2.103) and clavukerin A (Structure 2.104).188 In contrast, acetate is used for cetyl palmitate synthesis in Alcyonium molle, but not for de novo diterpene biosynthesis.188... 

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