Bismethylenedioxy

The reduction of the bismethylenedioxy derivative of prednisone, a 1,4-di-ene-3,11-dione, gives the llj -ol the conditions are 24 hours at room temperature in tetrahydrofuran. A similar surprising result was reported by... 

The dihydroxyacetone side chain is conveniently protected by forming 17a,20 20,21-bismethylenedioxy compounds (BMD) (92). Formation of llf -ethers as by-products from 11 -hydroxycompounds (91) can be limited by using formalin with a low methanol content, or better with paraformaldehyde as a source of alcohol-free formaldehyde. ... 

In contrast to this, hydrolysis of 17a,20 20,21-bismethylenedioxy-19-nor-9y ,10a-pregn-4-en-3-one using aqueous 90% formic acid at reflux temperature for 3 min gives an overall yield of 17a,21-dihydroxy-19-nor-9, 10a-pregn-4-ene-3,20-dione 21-formate of 12%. 

Hydroxyl groups are stable to peracids, but oxidation of an allylic alcohol during an attempted epoxidation reaction has been reported." The di-hydroxyacetone side chain is usually protected during the peracid reaction, either by acetylation or by formation of a bismethylenedioxy derivative. To obtain high yields of epoxides it is essential to avoid high reaction temperatures and a strongly acidic medium. The products of epoxidation of enol acetates are especially sensitive to heat or acid and can easily rearrange to keto acetates. 

Methyl-17.20 20.21-bismethylenedioxy-3,3-ethylene-dioxy-5 -pregnane-6.11-dione ... 

This nitrite (5 g) is dissolved in 200 ml of toluene and photolyzed For 2 hr at 20° as described above. Without further treatment the solution is chromatographed on 100 g of alumina and eluted with methylene dichloride containing increasing proportions of methanol. The first fraction gives 0.6g prednisolone BMD. The latter fractions afford 17,20 20,21-bismethylenedioxy-llj5-hydroxy-18-oximinopregna-l,4-dien-3-one (3 g) mp 270-274° [oc]d 0°, after crystallization from ethyl acetate-hexane. 

Bis-(iodomethyl)zinc-zinc iodide, 108 17 a,20 20,21-Bismethylenedioxy- U,2 -di-hydroxypregn-4-ene-3,11 -dione, 425 17a,20 20,21-Bismethylenedioxy-3,3-ethyl-enedioxy-5a,6a-oxidopregnan-l 1-one and 5 3,6p-oxide, 3... 

Methylandrost-5-ene-3/8,17a-diol, 63 Methylation of a-oxalyl ketones, 95 5 -Methyl-17a,20 20,21-bismethylenedioxy-3,3-ethylenedioxy-5/8-pregnane-6,l 1-dione, 93... 

A bismethylenedioxy group in a 4-chloro or 11-keto steroid is stable to cleavage by formic acid or glacial acetic acid (100°, 6 h). The tetramethyl derivative is readily hydrolyzed (50% AcOH, 90°, 3-4 h, 80-90% yield). ... 

Bile acids, steroids from, 188 Biperidin, 47 Birch, Arthur J., 163 Birch reduction, 163, 167, 170 Bishydroxycoumarin, 331 Bismethylenedioxy group, 193 Blocking agents, of B-sympathet-ic receptors, 65, 117... 

Bismethylenedioxy protecting group, 190 p-Blockers, 41 Blood-brain barrier, 52,... 

System (3) described the use of stable-isotope-dilution mass spectrometry for the simultaneous determination of cortisol, cortisone, prednisolone, and prednisone in plasma [177]. Cortisol, cortisone, prednisolone, and prednisone were simultaneously extracted from acidified plasma on a Sep-Pak Ci8 cartridge. The column was eluted with methanol, the eluent evaporated, and the residue compounds reacted to their bismethylenedioxy-3-heptafluoro-n-butyryl derivatives by treatment with formaldehyde and heptafluoro-n-butyric anhydride. The derivatives were... 

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