Derivatives of 2-Pyrazolin-5-one. II. Catalyzed Sodium Borohydride Reduction of Some 4–(2-Nitrobenzylidene)-2-pyrazolin-5-ones. A Reappraisal

1975 ◽  
Vol 53 (23) ◽  
pp. 3637-3644 ◽  
Author(s):  
Ronald T. Coutts ◽  
Abdel-Monaem El-Hawari
Keyword(s):  
Physical Properties ◽  
Sodium Borohydride ◽  
Reduction Product ◽  
Borohydride Reduction ◽  
Sodium Borohydride Reduction ◽  
Derivatives Of

A reexamination of the sodium borohydride and palladium–charcoal reduction of 3-methyl-4-(o-nitrobenzylidene)-1-phenyl-2-pyrazolin-5-one (3a) has revealed that the final product is 3-methyl-4-(o-aminobenzyl)-1-phenyl-2-pyrazolin-5-one (5a), and not 9-hydroxy-3-methyl-3a,4,9,9a-tetrahydro-1H-pyrazolo[3,4-b]quinoline as claimed previously. Reduction of 3a to 5a proceeds via the 4-(o-nitrobenzyl) compound. Chemical and physical properties of 5a are described which support the assignment of this revised structure to the reduction product of 3a. Two analogs of 3a were also reduced in the same manner and yielded products analogous to 5a and not the previously claimed pyrazolo[3,4-b]quinolines.

THE PREPARATION OF 3-ALKYLTHIOINDOLES

1965 ◽  
Vol 43 (5) ◽  
pp. 1293-1297 ◽  
Author(s):  
R. V. Jardine ◽  
R. K. Brown
Keyword(s):  
Sodium Borohydride ◽  
Condensation Product ◽  
Ethyl Iodide ◽  
Reduction Product ◽  
Diethyl Acetal ◽  
Borohydride Reduction ◽  
Phosphorus Pentasulfide ◽  
Fischer Cyclization ◽  
Sodium Borohydride Reduction

3-Ethylthioindole has been prepared by Fischer cyclization of the condensation product of phenylhydrazine and ethylthioacetaldehyde diethyl acetal, and also by a route involving the reaction of ethyl iodide with the sodium borohydride reduction product of 1,2-dithiolo[4,3-b]indole-3-(4H)-thione. The last-named compound was obtained by reaction of 2-carbethoxy-indoxyl with phosphorus pentasulfide.

Polybrominated derivatives of 5α-androstane and 5α-estrane 3-ketones: cyclopropanol formation

1976 ◽  
Vol 54 (18) ◽  
pp. 2865-2870 ◽  
Author(s):  
J. F. Templeton ◽  
C. W. Wie ◽  
F. E. Hruska
Keyword(s):  
Magnetic Resonance ◽  
Sodium Borohydride ◽  
Proton Magnetic Resonance ◽  
Spectroscopic Methods ◽  
Borohydride Reduction ◽  
Magnetic Resonance Data ◽  
Resonance Data ◽  
Sodium Borohydride Reduction ◽  
Derivatives Of ◽  
Proton Magnetic Resonance Data

Bromohydrin acetates from sodium borohydride reduction of di- and tribrominated 17β-hydroxy-5α-androstan-3-one and 17β-hydroxy-5α-estran-3-one have been prepared and their structures determined by spectroscopic methods. Some 220 MHz proton magnetic resonance data are reported for structure determination. The formation of cyclosteroid derivatives by 1,3-elimination of bromine with zinc–copper couple is discussed.

The Cotton Effects of Conjugated Homoannular Dienes. I. The Non-generality of the Rule of Moscowitz

1972 ◽  
Vol 50 (9) ◽  
pp. 1433-1437 ◽  
Author(s):  
J. Lessard ◽  
L. Ruest ◽  
Ch. R. Engel
Keyword(s):  
Sodium Borohydride ◽  
Cotton Effect ◽  
Crystallographic Analysis ◽  
Reduction Product ◽  
Borohydride Reduction ◽  
X Ray ◽  
Cotton Effects ◽  
Sodium Borohydride Reduction

The non-generality of the diene rule of Moscowitz, relating the helicity of a non-planar conjugated homoannular diene to the sign of its Cotton effect, is discussed. We report the preparation of 3β-bromoacetoxy-16α-ethyl-162-cyano-162,21-cyclo-5α-pregna-17,21-diene, the X-ray crystallographic analysis of which confirms, as reported by Ahmed and Pollard, the stereochemistry which we previously assigned to the parent alcohol and acetate. We also report the synthesis of the methyl ketonic analogues of these dienonitriles and show that their sodium borohydride reduction product still has a Cotton effect in contradiction to the diene rule. The implications of these and other experiments are discussed.

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