New approach to steroidal hemisuccinates and glycosides

1987 ◽  
Vol 52 (3) ◽  
pp. 775-787 ◽  
Author(s):  
Vladimír Pouzar ◽  
Ivan Černý ◽  
Pavel Drašar ◽  
Miroslav Havel
Keyword(s):  
Final Stage ◽  
Side Chain ◽  
Unsaturated Ester ◽  
New Approach ◽  
Ester Grouping ◽  
Primary Hydroxyl ◽  
New Synthesis

New synthesis of hemisuccinate and β-D-glucopyranoside of (20E)-21-ethoxycarbonyl-5,20-pregnadien-3β-ol (XVIII and XXVI) is described, consisting in the preparation of a protected hemisuccinate (XV) or glucoside (XXIII) intermediate, into which the unsaturated ester grouping in the side-chain is incorporated only in the final stage of the synthesis. The primary hydroxyl at C(20) was protected by tert-butyldimethylsilyl, trityl or nitrate groups, the succinate was blocked with 2-(trimethylsilyl)ethyl or 2,2,2-trichloroethyl groups and the glucosides were used in the form of peracetyl derivatives.

A Novel Scheme for the Synthesis of 21-Acetoxypregna-1,4,9(11)-triene- 17α,21-diol-3,20-dione from 9α-Hydroxyandrostenedione

2020 ◽  
Vol 16 (5) ◽  
pp. 606-610
Author(s):  
Nguyen T. Diep ◽  
Luu D. Huy
Keyword(s):  
Double Bond ◽  
Chemical Synthesis ◽  
Economic Efficiency ◽  
Final Stage ◽  
Side Chain ◽  
Entire Process ◽  
Drug Synthesis ◽  
First Time

Background: Vietnam currently imports up to 90% of the pharmaceuticals it consumes and 100% of the steroid-based pharmaceuticals. The ability for efficient chemical synthesis of the steroids could create commercial opportunities to address this issue. Synthesis of 21-acetoxypregna-1,4,9(11)- triene-17α,21-diol-3,20-dione is considered a key intermediate in the scheme of steroidal drug synthesis. Previous synthesis attempts of such steroids (corticoids) introduce a double bond at C-1(2) in the final stage of synthesis, which delivers a poor yield and reduces the economic efficiency of the process. Objective: To study and develop a novel and effective method for the synthesis of 21-acetoxypregna- 1,4,9(11)-triene-17α,21-diol-3,20-dione. Methods: Using 9α-hydroxyandrostenedione as a substrate chemical synthesis was performed as follows: pregnane side chain construction at C-17 (acetylene method), introduction of C-1(2) double bond (using SeO2), epimerization of C-17 (via 17-ONO2 ester) and Stork’s iodination. Results: 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione was prepared from 9α- hydroxyandrostenedione with an improved yield compared to previous attempts. Conclusion: Here, 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione has been synthesized from 9α-hydroxyandrostenedione based on a novel, effective and commercially feasible scheme. The introduction of the C-1(2) double bond at an earlier stage of the synthesis has increased the economic efficiency of the entire process. For the first time, the indirect epimerization mechanism has been clarified along with the configuration of the C-17 stereo-center which has been confirmed using NOESY data.

Concise Synthesis of the Terpene Core Structure of Suaveolindole Through a Time-Economic Route

Synlett ◽  
2021 ◽  
Author(s):  
Hiroki Tanimoto ◽  
Kazuki Tojo ◽  
Tsumoru Morimoto ◽  
Kiyomi Kakiuchi
Keyword(s):  
Claisen Rearrangement ◽  
Core Structure ◽  
Side Chain ◽  
Unsaturated Ester ◽  
Synthetic Route ◽  
Carbon Side Chain

The terpene core structure of suaveolindoles was synthesized through a concise route in a time-economical manner. A scalable synthetic route from pulegone delivered the desired α,β,γ,δ-unsaturated ester in a brief period. By way of Eschenmoser-Claisen rearrangement, carbon side chain moiety at the crowded double-allylic position was introduced stereoselectively.

Enantioselective synthesis of 1-aryl-2-propenylamines: a new approach to a stereoselective synthesis of the Taxol® side chain

2004 ◽  
Vol 15 (6) ◽  
pp. 941-949 ◽  
Author(s):  
Daniele Castagnolo ◽  
Silvia Armaroli ◽  
Federico Corelli ◽  
Maurizio Botta
Keyword(s):  
Stereoselective Synthesis ◽  
Enantioselective Synthesis ◽  
Side Chain ◽  
New Approach

A new synthesis of castasterone and brassinolide from stigmasterol. A concise and stereoselective elaboration of the side chain from a C-22 aldehyde

1993 ◽  
Vol 71 (2) ◽  
pp. 156-163 ◽  
Author(s):  
Thomas G. Back ◽  
Peter G. Blazecka ◽  
M. Vijaya Krishna
Keyword(s):  
Catalytic Amount ◽  
Allylic Alcohol ◽  
Side Chain ◽  
Epoxy Alcohol ◽  
New Synthesis ◽  
Epoxide Opening ◽  
Cuprous Cyanide ◽  
Hydrolysis Of ◽  
Villiger Oxidation

Brassinolide (1) and castasterone (2) were prepared from aldehyde 7, in turn available from stigmasterol (3). The addition of (E)-1-propenyllithium to 7, followed by diastereoselective Sharpless epoxidation of allylic alcohol 8 using (L)-(+)-diethyl tartrate, and regioselective epoxide-opening of (threo) epoxy alcohol 15 with isopropylmagnesium chloride in the presence of a catalytic amount of cuprous cyanide afforded diol 17. The epoxidation and cuprate addition steps were investigated in greater detail with the simpler model aldehyde 4. Hydrolysis of 17 provided 2, which was converted preferentially into 1 or its regioisomer 22 by Baeyer–Villiger oxidation with trifluoroperoxyacetic acid or peroxyseleninic acids, respectively.

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