Neighbouring hydroxy-group participation in the reductive elimination of chlorine from 5α,6β-dichlorocholestanes with sodium borohydride

1975 ◽  
pp. 277-281 ◽  
Author(s):  
Yoram Houminer
Keyword(s):  
Hydroxy Group ◽  
Sodium Borohydride ◽  
Reductive Elimination ◽  
Group Participation

scholarly journals Neighbouring Group Participation in the Methanolysis of a Vicinal Diepoxide

1999 ◽  
Vol 23 (6) ◽  
pp. 356-357
Author(s):  
James R. Hanson ◽  
Peter B. Hitchcock ◽  
Ismail Kiran
Keyword(s):  
Hydroxy Group ◽  
Group Participation ◽  
Neighbouring Group Participation

The tetracyanoethylene catalysed methanolysis of 17β-acetoxy-4β,5β:6α,7α-diepoxyandrostane afforded 17β-acetoxy-4α,7α-oxido-5β-hydroxy-6β-methoxyandrostane in which the methanolysis product of the 6α,7α-epoxide has participated in the cleavage of the 4β,5β-epoxide; the reaction is modified however by an adjacent 3β-hydroxy group.

Synthesis and Antibacterial Activity of Some 3-Hydroxyquinolones

1992 ◽  
Vol 57 (1) ◽  
pp. 188-193 ◽  
Author(s):  
Stanislav Rádl ◽  
Magda Janichová
Keyword(s):  
Antibacterial Activity ◽  
Carboxylic Acid ◽  
Hydroxy Group ◽  
Sodium Borohydride ◽  
Selenium Dioxide ◽  
Prolonged Heating

A reductive decarboxylation of 7-chloro-1-ethyl-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (Id) with sodium borohydride provided the respective 1,2,3,4-tetrahydro derivative Va, which was treated with selenium dioxide to give product of dehydrogenation VIa. 3-Acetyl-1-ethyl-1,4-dihydroquinolin-4-ones VIb and VIc were oxidized with 3-chloroperoxybenzoic acid to the respective 3-hydroxyderivatives IIIa and IIIb. Compound IIIb was benzylated on a hydroxy group at position 3 to corresponding 3-benzyloxy derivative VIf which after prolonged heating with N-methylpiperazine in a sealed tube provided directly 3-hydroxy-7-(4-methyl-1-piperazinyl) derivative IIIc.

Reductive elimination of 1,2-dibromides with sodium borohydrides

1968 ◽  
Vol 46 (5) ◽  
pp. 805-808 ◽  
Author(s):  
J. F. King ◽  
A. D. Allbutt ◽  
R. G. Pews
Keyword(s):  
Sodium Borohydride ◽  
Reductive Elimination

Sodium trimethoxyborohydride or a 1:3 mixture of sodium borohydride and sodium tetramethylborate reacts with a number of vicinal dibromides to form the corresponding olefin. Variable (sometimes good) yields were obtained when the bromine atoms were on secondary or tertiary carbons, but little or no olefin was detected when one bromine was primary.

Synthesis and Biological Activity of New 16,17-Secoestrone Derivatives

2000 ◽  
Vol 65 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Suzana Jovanović-Šanta ◽  
Silvana Andrić ◽  
Radmila Kovačević ◽  
Vjera Pejanović
Keyword(s):  
Biological Activity ◽  
Hydroxy Group ◽  
Sodium Borohydride ◽  
Estrogenic Activity ◽  
Complete Loss ◽  
Borohydride Reduction ◽  
Experimental Animals ◽  
Biological Tests ◽  
Sodium Borohydride Reduction

Starting from estrone 3-benzyloxy-17β-hydroxyestra-1,3,5(10)-trien-16-one oxime (3b) was synthesized, which underwent Beckmann fragmentation giving the 3-benzyloxy-17-oxo- 16,17-secoestra-1,3,5(10)-triene-16-nitrile (4b). Sodium borohydride reduction of this compound afforded 3-benzyloxy-17-hydroxy-16,17-secoestra-1,3,5(10)-triene-16-nitrile (5b). The deprotection of the 3-hydroxy group was achieved by action of hydrogen upon derivatives 4b and 5b in presence of Pd/C as a catalyst, yielding 3-hydroxy-17-oxo-16,17-secoestra- 1,3,5(10)-triene-16-nitrile (4a) and 3,17-dihydroxy-16,17-secoestra-1,3,5(10)-triene-16-nitrile (5a). In biological tests on experimental animals, compounds 4a, 4b, 5a and 5b showed virtually a complete loss of estrogenic activity, whereas compounds 4a, 5a and 5b exhibited moderate antiestrogenic effect.

Preparation of 12,20-disubstituted lupane derivatives

1979 ◽  
Vol 44 (1) ◽  
pp. 194-210 ◽  
Author(s):  
Vladimír Pouzar ◽  
Alois Vystrčil
Keyword(s):  
Hydroxy Group ◽  
Sodium Borohydride ◽  
Nmr Spectra ◽  
Unsaturated Ketone ◽  
Lithium Aluminium Hydride ◽  
H Nmr ◽  
Unsaturated Alcohols ◽  
Lithium Aluminium ◽  
Primary Hydroxy Group ◽  
Derivatives Of

Ketoester I was reduced to diol VI. The higher reactivity of its primary hydroxy group was made use of for the preparation of 12α-hydroxy derivatives VII, VIII and X the oxidation of which led to oxo derivatives XII, XIII and XIV. The reduction of the 12-oxo group in compounds XII and XIV with lithium aluminium hydride takes place stereospecifically under formation of 12α-hydroxy derivatives VII and X, while on reduction with sodium in 1-propanol corresponding 12β-hydroxy derivatives XV and XVI are also formed. Reduction of the unsaturated ketone XVII with sodium borohydride gave unsaturated alcohols XVIII and XX. As acetoxy ketone XXIV was obtained from olefin XIX in a 12% yield only, its alternative preparation was carried out from acetoxy ketone XXXIV via the intermediates XXXII, XXXV, XXVIII and XXXI in an overall yield of 27%. The structures of the derivatives of 12-lupene (III, V, XVII, XIX and XXI), 12-lupanol (II, VII, X, XV, XXXI and XXVII) and 12-lupanone (I, XII, XIII, XIV, XXIII, XXIV, XXXIII and XXXIV) were confirmed by the analysis of their 1H NMR spectra.

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