5424-40-8Relevant academic research and scientific papers
Expedited Baeyer-Villiger oxidation of steroidal ketones by microwave irradiation
Borah, Juri Moni,Chowdhury, Pritish
experimental part, p. 1341 - 1345 (2011/11/06)
Microwave (MW) assisted reactions are currently having considerable importance in the synthesis of organic compounds. Considering the remarkable application of Baeyer-Villiger (BV) reaction in the synthesis of natural products and steroid-peptide conjugates, we report here some of our findings of BV oxidation of carbonyl compounds with special reference to steroidal ketones under MW irradiation justifying its accelerating effect.
Ceric ammonium nitrate (CAN) catalyzed Baeyer-Villiger oxidation of carbonyl compounds, specially 20-oxosteroids
Goswami, Papori,Hazarika, Saroj,Das, Archana M.,Chowdhury, Pritish
, p. 1275 - 1281 (2007/10/03)
The role of ceric ammonium nitrate (CAN) as an effective catalyst in the peracid induced Baeyer-Villiger oxidation of carbonyl compounds with special reference to steroids has been demonstrated.
Microwave induced selective enolization of steroidal ketones and efficient acetylation of sterols in semisolid state
Marwah, Padma,Marwah, Ashok,Lardy, Henry A.
, p. 2273 - 2287 (2007/10/03)
Under microwave irradiation steroidal enones, more specifically, position three carbonyls were efficiently and selectively converted to the corresponding enol acetates in the presence of additional enolizable carbonyl functions at other positions, using acetic anhydride and a catalytic amount of toluene-p-sulfonic acid. Acetylation of hydroxyl groups of the sterols, including those at the hindered positions, was near quantitative. Strictly anhydrous conditions were not a pre-requisite for acetylation and the reaction system easily tolerated up to 10% (v/v) moisture.
Steroidal N-Nitro-amines. Part 2. Denitroamination of Steroidal 12β-, 17β-, 20β-, and 23R-Nitro-amines
Francisco, Cosme G.,Freire, Raimundo,Hernandez, Rosendo,Melian, Daniel,Salazar, Jose A.,Suarez, Ernesto
, p. 297 - 304 (2007/10/02)
20β-Nitroaminopregn-5-en-3β-yl acetate (13a), 17β-nitroamino-5α-androstan-3β-yl acetate (14), and 12β-nitroamino-(25R)-5α-spirostan-3β-yl acetate (15a) have been prepared by nitrosation of the corresponding oximes, followed by reduction with sodium borohydride.The 23-nitro-imine (12), obtained by reaction of sarsasapogenin acetate (10) with nitrous acid and boron trifluoride-diethyl ether complex, was similarly reduced to give 23R-nitroamino-(20S,22S,25S)-5β-spirostan-3β-yl acetate (16).Denitroamination of (13a) was achieved by treatment with acetic anhydride and pyridine to give the acetates of pregna-5,20-dien-3β-ol (17), pregn-5-ene-3β,20β-diol (18), 17α-methyl-D-homo-androst-5-ene-3,17aβ-diol (19), and 17α-methyl-12a-methylene-C(12a)-homo-18-norandrost-5-en-3β-ol (20).Under the same conditions the nitro-amine (14) afforded the acetates of 5α-androst-16-en-3β-ol (27a), 17β-methyl-18-nor-5α-androst-12-en-3β-ol (28a), 17-methyl-18-nor-5α-androst-13(17)-en-3β-ol (29a), and 17β-methyl-18-nor-5α-androst-13-en-3β-ol (30a).Denitroamination of (15a) took place through the expected C-nor-D-homo rearrangement producing 14(13->12αH)abeo-(25R)-5α-spirost-13(18)-en-3β-yl acetate (31) in high yield and a minor amount of 14(13->12)abeo-(25R)-5α-spist-12-en-3β-yl acetate (32).The trans-stereochemistry of the β-hydrogen-elimination produced in the denitroamination of (16) was established by using labelled sarsasapogenin (10) biosynthesized by Agave attenuata from mevalonic acid.
