Steroidal α,β-epoxyketones. IV. Synthesis of the isomeric 6β-Bromo-4,5-epoxycholestan-3-ones

1965 ◽  
Vol 18 (7) ◽  
pp. 1049 ◽  
Author(s):  
DJ Collins ◽  
JJ Hobbs
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Sodium Borohydride ◽  
Hydrogen Bromide ◽  
High Yield ◽  
Borohydride Reduction ◽  
Compound Xiii ◽  
Alkaline Hydrogen Peroxide ◽  
Sodium Borohydride Reduction

6β-Bromocholest-4-en-3-one (I) was converted to 6β-bromo-4α,5-epoxy-5α-cholestan-3-one (II) with alkaline hydrogen peroxide. 5,6β-Dibromo-5α-cholestane- 3β,4β-diol (X) with alkali gave 6β-bromo-4β,5-epoxy-5β-cholestan-3β-ol (IXa), which was oxidized to non-crystalline 6β-bromo-4β,5-epoxy-5β-cholestan-3-one (XIII), characterized as the crystalline 3,3-dimethyl ketal (XIIa). Cleavage of (II) with hydrogen bromide in acetic acid gave 4,6β-dibromocholest-4-en-3-one (V) via the isomeric bromohydrins (IVa) and (IVb). Compound (XIII) yielded (V) directly. Sodium borohydride reduction of (I) gave cholesterol in high yield, while reduction with lithium tri-t-butoxyaluminium hydride afforded cholest-4-en-3-one (52%), cholesterol (30%), and cholest-4-en-6β-ol-3-one (7%).

scholarly journals Eine neue Methode zur Herstellung und Reinigung von 5-Methyltetrahydrofolsäure / A New Method for Preparation and Purification of 5-M ethyltetrahydrofolic Acid

1973 ◽  
Vol 28 (11-12) ◽  
pp. 650-652
Author(s):  
Harold Rüdiger ◽  
Reinhard Siede
Keyword(s):  
Acetic Acid ◽  
Folic Acid ◽  
Ion Exchange ◽  
Sodium Borohydride ◽  
Sodium Salt ◽  
Barium Salt ◽  
Borohydride Reduction ◽  
Methyl Derivative ◽  
Crude Product ◽  
Sodium Borohydride Reduction

Abstract 5-Methyltetrahydrofolic acid is prepared from folic acid by sodium borohydride reduction, reac­ tion with formaldehyde and reduction to the methyl derivative by sodium borohydride. The crude product is precipitated as barium salt which after having been converted to the sodium salt by ion exchange is adsorbed to QAE-Sephadex and eluted by different acetic acid gradients in subsequent chromatographies. This method allows to process gram quantities on reasonably small columns

Branched-chain sugar nucleosides. IV. 9-(3-Deoxy-3-C-"hydroxymethyl"-β(and α)-D-allofuranosyl and ribofuranosyl)adenine

1969 ◽  
Vol 47 (23) ◽  
pp. 4477-4481 ◽  
Author(s):  
Alex Rosenthal ◽  
Matej Sprinzl
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Methoxide ◽  
Titanium Tetrachloride ◽  
Total Yield ◽  
Borohydride Reduction ◽  
Peroxide Oxidation ◽  
Alkaline Hydrogen Peroxide ◽  
Sodium Metaperiodate ◽  
Sodium Borohydride Reduction ◽  
Branched Chain

Hydroboration followed by alkaline hydrogen peroxide oxidation of 1,2:5,6-di-O-isopropylidene-3-C-methylene-α-D-ribo-hexofuranose (2) yielded 3-deoxy-3-C-"hydroxymethyl"-1,2:5,6-di-O-isopropylidene-α-D-allofuranose (3) and partially hydrolyzed 3 in a total yield of 88%. Compound 3 was hydrolyzed selectively to the 1,2-monoisopropylidene derivative 5, which was converted via benzoylation followed by acetolysis into the 1,2-diacetate 7. Condensation of the latter compound with chloromercuri-N-benzoyladenine in the presence of titanium tetrachloride, followed by deblocking with methanolic sodium methoxide, yielded 9-(3-deoxy-3-C-"hydroxymethyl"-β(and α)-D-allofuranosyl)adenine in yields of 44 and 4% respectively, based on 7. The over-all yield of 10 based on 3 is 20%. Sodium metaperiodate oxidation of 10, followed by sodium borohydride reduction of the aldehydo-derivative, afforded 9-(3-deoxy-3-C-"hydroxymethyl"-β-D-ribofuranosyl)adenine (11) in 81% yield.Direct acetolysis of 3, followed by conversion of the mixture of peracetates into a mixture of glycosyl chlorides, and finally condensation of the latter with 8 gave the blocked crystalline β-D-nucleoside 9 in an over-all yield of about 9%, based on 3. Subsequent unblocking of 9 gave a nucleoside having the same physical constants as 10.

1,2-Benzothiazines. II. The Preparation and Sodium Borohydride Reduction of 3-Acyl-2H-1,2-benzothiazin-4(3H)-one 1,1-Dioxides1

1965 ◽  
Vol 30 (7) ◽  
pp. 2241-2246 ◽  
Author(s):  
Harold Zinnes ◽  
Roger A. Comes ◽  
Francis R. Zuleski ◽  
Albert N. Caro ◽  
John Shavel
Keyword(s):  
Sodium Borohydride ◽  
Borohydride Reduction ◽  
Sodium Borohydride Reduction
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