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Asymmetric reduction of steroidal 20-ketones: Chemical synthesis of corticosteroid derivatives containing and 20α, 21-diol and 17α, 20α, 21-triol side chains
| Content Provider | Semantic Scholar |
|---|---|
| Author | Han, Chun-Yang Monder, Carl |
| Copyright Year | 1983 |
| Abstract | Abstract A method is presented for the chemical synthesis of corticosteroid derivatives containing the 20α, 21-diol and 17α, 20α, 21-triol side chains. The ketol side chains of cortisol, corticosterone, 11-deoxycortisol, and 11-deoxycorticosterone were reduced at C-20 with sodium borohydride in a two-phase system consisting of aqueous calcium chloride and an organic phase of chloroform or ethyl acetate. Stereoselectivity of reduction was 92% α-oriented for cortisol and 79% α-oriented for 11-deoxycortisol at −27°. The 20α-form diminished relative to the 20β-form with increasing temperature. For the 17-deoxy steroids, reduction to the 20α-form was 23% for 11-deoxycorticosterone and 41% for corticosterone. The 20α 20β ratios of 17-deoxy steroids were unchanged between 0° and −27°. Calcium ions increased the solubility of corticosteroids in the aqueous phase. We propose that calcium ions affect the stereochemistry of reduction by forming a bidentate complex with the side chains of 17α-hydroxy steroids, fixing them in an orientation favorable to 20α-reduction, and by altering the phase partition of the steroids. |
| Starting Page | 619 |
| Ending Page | 626 |
| Page Count | 8 |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/0039-128X(83)90125-3 |
| Volume Number | 42 |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/0039128X83901253 |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/0039128X83901253?dgcid=api_sd_search-api-endpoint |
| Alternate Webpage(s) | https://doi.org/10.1016/0039-128X%2883%2990125-3 |
| Journal | Steroids |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
