A facile two-step high yield approach to 2-oxasteroids

Aryeh A. Frimer; Judith Hameiri-Buch; Shlomo Ripshtos; Pessia Gilinsky-Sharon

doi:10.1016/s0040-4020(01)88175-8

A facile two-step high yield approach to 2-oxasteroids

Aryeh A. Frimer
, Judith Hameiri-Buch
, Shlomo Ripshtos
, Pessia Gilinsky-Sharon

Bar-Ilan University

Research output: Contribution to journal › Article › peer-review

27 Scopus citations

Abstract

The base catalyzed autoxidation of 3-oxo-Δ⁴ steroids in aprotic media at circa -25°C occurs nearly exclusively at C₂ of the A-ring, generating rapidly (< 4 hrs) and in high yield the corresponding enol (2-hydroxy-3-oxo-Δ^1,4 analog) When the reaction is then allowed to continue at room temperature for several days, the enol is further autoxidized to the related lactol (1-hydroxy-2-oxa-3-oxo-Δ⁴ analog) in overall yields generally in the range of 85-95%. Sodium borohydride reduction of the lactol yields the pharmacologically important 2-oxasteroids.

Original language	English
Pages (from-to)	5693-5706
Number of pages	14
Journal	Tetrahedron
Volume	42
Issue number	20
DOIs	https://doi.org/10.1016/s0040-4020(01)88175-8
State	Published - 1986

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title = "A facile two-step high yield approach to 2-oxasteroids",

abstract = "The base catalyzed autoxidation of 3-oxo-Δ4 steroids in aprotic media at circa -25°C occurs nearly exclusively at C2 of the A-ring, generating rapidly (< 4 hrs) and in high yield the corresponding enol (2-hydroxy-3-oxo-Δ1,4 analog) When the reaction is then allowed to continue at room temperature for several days, the enol is further autoxidized to the related lactol (1-hydroxy-2-oxa-3-oxo-Δ4 analog) in overall yields generally in the range of 85-95\%. Sodium borohydride reduction of the lactol yields the pharmacologically important 2-oxasteroids.",

author = "Frimer, \{Aryeh A.\} and Judith Hameiri-Buch and Shlomo Ripshtos and Pessia Gilinsky-Sharon",

year = "1986",

doi = "10.1016/s0040-4020(01)88175-8",

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T1 - A facile two-step high yield approach to 2-oxasteroids

AU - Frimer, Aryeh A.

AU - Hameiri-Buch, Judith

AU - Ripshtos, Shlomo

AU - Gilinsky-Sharon, Pessia

PY - 1986

Y1 - 1986

N2 - The base catalyzed autoxidation of 3-oxo-Δ4 steroids in aprotic media at circa -25°C occurs nearly exclusively at C2 of the A-ring, generating rapidly (< 4 hrs) and in high yield the corresponding enol (2-hydroxy-3-oxo-Δ1,4 analog) When the reaction is then allowed to continue at room temperature for several days, the enol is further autoxidized to the related lactol (1-hydroxy-2-oxa-3-oxo-Δ4 analog) in overall yields generally in the range of 85-95%. Sodium borohydride reduction of the lactol yields the pharmacologically important 2-oxasteroids.

AB - The base catalyzed autoxidation of 3-oxo-Δ4 steroids in aprotic media at circa -25°C occurs nearly exclusively at C2 of the A-ring, generating rapidly (< 4 hrs) and in high yield the corresponding enol (2-hydroxy-3-oxo-Δ1,4 analog) When the reaction is then allowed to continue at room temperature for several days, the enol is further autoxidized to the related lactol (1-hydroxy-2-oxa-3-oxo-Δ4 analog) in overall yields generally in the range of 85-95%. Sodium borohydride reduction of the lactol yields the pharmacologically important 2-oxasteroids.

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EP - 5706

JO - Tetrahedron

JF - Tetrahedron

IS - 20

ER -

A facile two-step high yield approach to 2-oxasteroids

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