Calonectria

Hydroxylation 6a-Hydroxyandrostane 6a, 19-Dihydroxyandro--3,17-dione stane-3,17-dione Calonectria decora... 

Bird TG, PM Fredricks, ERH Jones, GD Meakins (1980) Microbiological hydroxylations. Part 23. Hydroxyl-ations of fluoro-5a-androstanones by the fnngi Calonectria decora, Rhizopus nigricans, and Aspsrgillus ohraceus. J Chem Soc Perkin 1 750-755. 

T.G.C. Bird, P.M. Fredericks, E.R.FI. Jones, G.D. Meakins, Microbiological hydroxylation. Part 23. Flydroxylations of fluoro-5ot-androstanones by the fungi Calonectria decora, Rhizopus nigricans, and Aspergillus ochraceus, J. Chem. Soc. Perkin Trans. 1 (1980) 750-755. 

Microbial and enzymic transformations of steroids have been reviewed. 5a-Pregnane-7,20-dione gave a reasonable yield of the la, 12/3-dihydroxy-derivative on incubation with Calonectria decora High yields of 10 8-hydroxy-19-nortes-tosterone were obtained by incubation of 19-nortestosterone with Rhizopus arr-hizus (Fischer 11). Oxidation of canrenone with a Penicillium species provided the 15a-hydroxy-derivative (348) which is a product of human metabolism of spironolactone.16j8-Hydroxylation of androstenolone, androst-4-ene-3,17-... 

Calonectria decora (ATCC 14767, NRRL 2380) Ascomycetes Steroid hydroxylation and dehydrogenadon, hydroxylation of cyclic hydro ub(ms... 

Generally speaking fungi are of greatest use in the hydroxylation of steroids, and five genera in particular have been found to be extremely useful these are Rhizopus, Calonectria, Aspergillus, Curvularia and Cunninghamella. 

As in the case of nonsteroidal substrates, the regioselectivity can also be influenced the stereochemistry of the reactant, for example hydroxylation of the 3a- and 3p-stereoisomers of the andiostan-17-one (69) by Calonectria decora gave different regioisomeric products (Scheme 11)/ In many cases mixtures of regioisomers are obtained. 

Using microbial strains such as Calonectria decora104, Daedalea rofescens105, or Rhizopus nigricans102, 3/ -hydroxylation occurs with simultaneous hydroxylation at the 7/ -, 12/ -, or 16/ -position of steroids. 

Hydroxylation in the 4/i-position of steroids is possible using the strain Calonectria deco-ra 30 104, however, 12/i-hydroxylation also occurs. 

The most important microorganism for the introduction of a hydroxy group in the 12/J-position of steroids is the pink fungus, Calonectria decora. Nevertheless, 12-hydroxylation is accompanied by the introduction of a second hydroxy group in the 15x-position. In the case of progesterone (1), a 77 % yield of 12/ .15a-dihydroxyprogesterone (2) has been reported234- 2 3S. 

The oxidation of progesterone with Rhizopus arrhizus yields lla-hy-droxyprogesterone [1075], together with 6p,lla-dihydroxyprogesterone [1076], In contrast, Calonectria decora converts progesterone into 12p,15p-dihydroxyprogesterone [575] (equation 403). 

A rational basis for interpreting the regiospecificity of steroid hydroxylation is emerging.12,28,29 With Calonectria decora and Rhizopus nigricans, the orientation of a steroid substrate appears to be controlled by interaction of the oxygen functions with hydrophilic sites (such as A or B) at the active sites of the hydroxylases. Thus, 5 and bind in a similar manner and hydroxylation occurs from the same active site location to give the 11a- or 7a-0H product respectively,28 approximately 5.5 A away from the initial oxygen function. This relationship was also observed in hydroxyla-tions of cyclic alcohols and acylated amines by Sporotrichum sulfures-cens.30... 

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