Epoxidation of Diosgenin, 25(R)-1,4,6-Spirostatrien-3-one and 25(R)-4,6-Spirostadien-3β-ol

Abstract

Upon treatment of 25(R)-spirost-5-en-3β-ol (diosgenin), 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with 30% H2O2 and 5% NaOH in methanol, diosgenin did not react, 25(R)-1,4,6-spirostatrien-3-one was converted to 25(R)-1α,2α-epoxy-4,6-spirostadien-3-one and 25(R)-4,6-spirostadien-3β-ol was oxidized to give a small amount of 25(R)-4,6-spirostadien-3-one, while most of the original starting material remained unchanged. On the other hand, reactions of diosgenin, 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with m-chloroperoxy-benzoic acid in chloroform yielded 25(R)-5α,6α-epoxyspirostan-3β-ol, 25(R)-6α,7α-epoxy-1,4-spirostadien-3-one and 25(R)-4β,5β-epoxy-6-spirosten-3β-ol, respectively.

Synthesis of New Steroidal Carbamates with Plant-Growth-Promoting Activity: Theoretical and Experimental Evidence

“…Synthesis of carbamate 15 from diosgenin goes through the intermediate 14 that is obtained by a three-step sequence including epoxidation of diosgenin with meta -chloroperoxybenzoic acid ( m -CPBA) [ 41 ], acid-catalyzed epoxide opening [ 42 ], and selective oxidation of axial -OH group at position C6 with N -bromosuccinimide (NBS) [ 43 ] ( Scheme 2 ).…”

Highly Oxygenated 11‐Keto‐β‐boswellic Acid Analogues and Their Anti‐Inflammatory Potential

“…Epoxy‐1α,9α‐dihydroxy‐11‐oxo‐urs‐12‐en‐24‐oic acid ( 11 ) was synthesized by epoxidation of 1α,9α‐dihydroxy derivative 5 followed by hydrogenolysis as shown in Scheme . Prilezhaev epoxidation of compound 5 with m ‐chloroperbenzoic acid ( m ‐CPBA) afforded epoxy compound 10 with 91% yield. The shielding effect of axially oriented benzyl ester favored the formation of equatorially oriented epoxy compound 10 exclusively probably further assisted by the directing effects of the axial 1‐OH group.…”

“…Compound 14 was obtained in three steps from benzyl ester 3 as outlined in Scheme . Prilezhaev epoxidation of benzyl ester 3 with m ‐chloroperbenzoic acid in chloroform afforded epoxide 12 with 87% yield. Equatorially oriented epoxidation most preferably occurred due to the shielding effect of axially positioned benzyl ester that restricted the reagent to attack from the same side.…”