scholarly journals CCXXVII.—The formation of bromine derivatives of carbon compounds without the production of hydrogen bromide

1922 ◽  
Vol 121 (0) ◽  
pp. 1896-1904 ◽  
Author(s):  
Biraj Mohan Gupta ◽  
Jocelyn Field Thorpe
Keyword(s):  
Hydrogen Bromide ◽  
Production Of Hydrogen ◽  
Carbon Compounds ◽  
Derivatives Of

scholarly journals The Reaction of Derivatives of D-Xylal and D-Arabinal with Hydrogen Chloride and Hydrogen Bromide.

1969 ◽  
Vol 23 ◽  
pp. 2083-2094 ◽  
Author(s):  
Klaus Bock ◽  
Inge Lundt ◽  
Christian Pedersen ◽  
Tord Holme ◽  
Alf A. Lindberg ◽  
...  
Keyword(s):  
Hydrogen Chloride ◽  
Hydrogen Bromide ◽  
Derivatives Of

4,5-Seco-4,6-cyclosteroids. III. Observations on the course of reductive rearrangement of 6β-Bromo-4β,5-epoxy-5β-cholestan-3β-ol

1969 ◽  
Vol 22 (4) ◽  
pp. 807 ◽  
Author(s):  
DJ Collins ◽  
JJ Hobbs ◽  
RJ Rawson
Keyword(s):  
Hydrogen Bromide ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Experimental Conditions ◽  
Lithium Aluminium ◽  
Reaction Proceeds ◽  
Derivatives Of

It has been shown that reductive rearrangement of 6β-bromo-4β,5-epoxy- 5β-cholestan-3β-ol (I) to 4,5-seco-4,6-cycle-6β-cholestane-3β,5α-diol (IXa) with lithium aluminium hydride in tetrahydrofuran proceeds via 6β-bromo-5β-cholestane-3β,5-diol (IIa). Relevant reactions of the latter and the corresponding 3-ketone are discussed. ��� Similar conversion of the 3-epimer of (I) into 4,5-seco-4,6-cyclo- 6β-cholestane-3α,5α-diol (XIIIa) in high yield indicates that reductive rearrangement of the 6β-bromo-5β-hydroxy moiety proceeds without participation of the 3-aluminate complex. Some derivatives of (XIIIa) are described. ��� Experimental conditions required for the conversion of (I) into (IXa) are defined. ��� Combined evidence indicates that the reaction proceeds in a concerted manner by essentially base-catalysed, 1,3-elimination of hydrogen bromide from diol (IIa) with 4,5-bond migration to give the formal intermediate 3β-hydroxy-4,5-seco-4,6-cyclo-6β-cholestan-5-one (VI), further reduced to (IXa).

Preparation of the 1-(2,5-anhydro-β-d-arabinofuranosyl) derivatives of cytosine and uracil and their cleavage with hydrogen bromide

1982 ◽  
Vol 47 (11) ◽  
pp. 2961-2968 ◽  
Author(s):  
Hubert Hřebabecký ◽  
Josef Brokeš ◽  
Jiří Beránek
Keyword(s):  
Aqueous Solution ◽  
Sodium Hydroxide ◽  
Hydrogen Bromide ◽  
Ion Exchanger ◽  
Alternative Synthesis ◽  
Derivatives Of ◽  
Uracil Derivative

Anhydronucleoside Ia was prepared from chloroarabinofuranosylcytosine IIIc or from 2,2'-anhydro-1-(5-chloro-5-deoxy-β-D-arabinofuranosyl)cytosine by the action of a strongly basic ion exchanger. The anhydro derivative IIa was prepared from 2,2'-anhydro-1-(5-chloro-5-deoxy-β-D-arabinofuranosyl)uracil by treatment with aqueous solution of sodium hydroxide. The action of hydrogen bromide in dimethylformamide on 2',5'-anhydronucleosides Ia and IIa leads both to the cleavage of the anhydro bond under formation of the 5'-bromo derivatives IIIa and IVa and to the cleavage of nucleosidic bond. In case of the uracil derivative IIa, the α-arabinofuranosyl derivative V was also isolated after preceding acetylation. For unambiguous proof of the structure, an alternative synthesis of compound V was performed.

THE ACTION OF SULPHURIC ACID ON CERTAIN DERIVATIVES OF CYCLOPROPANE

1933 ◽  
Vol 9 (2) ◽  
pp. 159-168 ◽  
Author(s):  
Charles F. H. Allen ◽  
Raymond Boyer
Keyword(s):  
Acetic Acid ◽  
Sulphuric Acid ◽  
Hydrogen Bromide ◽  
Cyclopropane Ring ◽  
Secondary Reaction ◽  
Derivatives Of ◽  
Cyclopropane Derivatives

A considerable variety of ketocyclopropanes has been submitted to the action of sulphuric acid, alone or in acetic acid. In general, the mode of reaction was similar to, though less drastic than, that of hydrogen bromide; this indicated a similar mechanism. When the cyclopropane ring was attacked, the product isolated was apparently formed by the addition of a molecule of water or acetic acid, or was the result of a secondary reaction dependent on a primary product so formed. The nitriles were hydrolyzed to amides without opening of the ring. A mechanism is suggested to account for the ring scission of cyclopropyl alcohols, which takes place in a different manner from most cyclopropane derivatives.

scholarly journals BROMINATION OF AROMATIC AMINES

2019 ◽  
Vol 62 (4) ◽  
pp. 47-59
Author(s):  
Fatima A. Mustafayeva ◽  
Najaf T. Kakhramanov
Keyword(s):  
Aromatic Amines ◽  
Hydrogen Bromide ◽  
Point Of View ◽  
Molar Ratio ◽  
Ammonium Bromide ◽  
Solvent Free Conditions ◽  
Environmentally Safe ◽  
Bromination Reaction ◽  
Radiation Conditions ◽  
Derivatives Of

It is known that the antipyrenes, biological active substances (antitumor, antibacterial, antifungal, antiviral), pharmacological preparations on the basis of bromine-containing aromatic compounds are widely used in the industry. Considering this and increased demand for these substances the purpose of this work was to summarize and systematize the accumulated knowledge in this area. The article presents methods and reagent systems used in the bromination of aromatic amines. There have been described the bromination of aromatic amines with hydrogen bromide, sodium bromide, potassium bromide, ammonium bromide, copper (II) bromide, N-bromosuccinimide, N-bromosaccharin, polymer-supported halogenation agents, and difference of these methods from the point of view of the used oxidizer, the medium and the solvent, the catalyst, the regioselectivity, the quantity of bromine atoms in the obtained product. The influence of solvents, catalysts, the nature (electron-donor or electron-acceptor) and position (ortho-, meta-, para-) of the substituents in the aromatic ring, reaction conditions, molar ratio of the reagents, reaction temperature and carrying out time of bromination reaction of aromatic amines has been shown. The bromination reactions courses of aromatic amines in different solvents, in solvent free conditions, in solid states has been described. The bromination of aromatic amines under thermal, microwave, ultraviolet radiation conditions has been studied. In the paper the regioselective monobromination and also obtaining of di-, tri- bromo derivatives of aromatic amines has been shown. Taking into account today's priority to environmentally safe methods of bromination of aromatic amines they have been also mentioned. Given the above, in our opinion, the information presented in this article will help to optimize the production of bromo derivatives of aromatic amines used in industry, technics and technology.

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