An Efficient Procedure for the Synthesis of 21-Acetoxypregna-1,4,9(11),16- tetraene-3,20-dione

Author(s): Luu D. Huy*, Nguyen T. Diep, Tran K. Vu, Tatiana S. Savinova, Marina V. Donova.

Journal Name: Combinatorial Chemistry & High Throughput Screening
Accelerated Technologies for Biotechnology, Bioassays, Medicinal Chemistry and Natural Products Research

Volume 23 , Issue 3 , 2020

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Background: Halogenated corticosteroids are widely used in medicine, and the global need of these steroidal APIs is estimated to be 40 – 70 tons, annually. Vietnam currently imports the pharmaceutical compounds up to 90%, in particular 100% of steroidal drugs. Currently, industrial production is based on the chemical syntheses of corticosteroids from either 16- dehydropregnenolone acetate (obtained from diosgenin) or androstenedione (obtained from phytosterol). The development of shorter synthetic schemes and more economically feasible technologies is of great significance. Introduction of 1(2)-double bond at the final stages of the corticosteroids synthesis results inpoor yield. 21-Acetoxypregna-1,4,9(11),16-tetraene-3,20-dione (tetraene acetate) is a key intermediate in the synthesis of highly active halogenated corticosteroids such as dexamethasone and other halogenated corticosteroids. 21-acetoxypregna-1,4,9(11),16- tetraene-3,20-dione is a key intermediate in the synthesis of dexamethasone from the readily available and cheap 9α-hydroxyandrost-4-ene-3,17-dione.

Objective: The purpose of this study was the development of an efficient and shorter procedure for the synthesis of 21-acetoxypregna-1,4,9(11),16-tetraene-3,20-dione from 9α-hydroxyandrostenedione, which is a product of a bio-oxidative degradation of the side chain of phytosterols.

Methods: Pregnane side chain was constructed using cyanohydrin method. For 1(2)- dehydrogenation, selene dioxide was applied for the introduction of Δ1(2)-double bond. Other stages of the synthesis were epimerization, Stork’s iodination procedure and dehydration.

Result: 21-Acetoxypregna-1,4,9(11),16-tetraene-3,20-dione was prepared from 9α- hydroxyandrostenedione in yield more than 46%.

Conclusion: An efficient and practically feasible procedure for the synthesis of 21-acetoxypregna- 1,4,9(11),16-tetraene-3,20-dione from 9α-hydroxyandrostenedione, a key intermediate for the synthesis of 9-haloidated corticoids, has been developed. The procedure can be applied for the production of value-added 9-haloidated corticoids.

Keywords: 9α-hydroxyandrostenedione, 21-acetoxypregna-1, 4, 9(11), 16-tetraene-3, 20-dione, dehydration, hydrocyanation, acetoxylation, dehydrogenation.

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Article Details

Year: 2020
Page: [225 - 231]
Pages: 7
DOI: 10.2174/1386207323666200219122644
Price: $65

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