Cyanogen bromide, reaction with

The proposed structure of 97 isolated from broiled sardines was confirmed by straightforward synthesis starting from5,6-diaminoquinolines. After reaction with cyanogen bromide it afforded the 2-amino-imidazo[4,5-/]quinolines 99 (R = H, Me), which was then converted into its 3-A-methyl derivative 100 by... 

Reaction with cyanogen bromide possibly gives cyanamide 131... 

Proteins can be cleaved specifically at the amide bond on the carboxyl side of methionine residues by reaction with cyanogen bromide. BrC=N. 

A number of amidines have anthelmintic activity. Bunamidine (25), indicated for treatment of human pinworm infestations, is prepared from a-naphthylhexyl-ether (23) by Friedel-Crafts type reaction with cyanogen bromide and aluminum chloride to give nitrile (24). This, then, is reacted with the magnesium bromide salt of di-n-propylamine leading to the naph-thamidine structure (25). -... 

In this series, too, replacement of the N-methyl by a group such as cyclopropylmethyl leads to a compound with reduced abuse potential by virtue of mixed agonist-antagonist action. To accomplish this, reduction of 24 followed by reaction with tertiary butylmagnesium chloride gives the tertiary carbinol 27. The N-methyl group is then removed by the classic von Braun procedure. Thus, reaction with cyanogen bromide leads to the N-cyano derivative (28) hydrolysis affords the secondary amine 29. (One of the more efficient demethylation procedures, such as reaction with ethyl chloroformate would presumably be used today.) Acylation with cyclopropylcarbonyl chloride then leads to the amide 30. Reduction with lithium aluminum hydride (31) followed by demethylation of the phenolic ether affords buprenorphine (32).9... 

The reaction with cyanogen bromide presumably can also be carried out succesfully with ROCLi in Et20-hexane mixtures or with acetylenic Crignard derivatives (at higher temperatures) in Et20 or THF. 

A different approach to surface functionalization involves direct activation of the silanol groups by reaction with cyanogen bromide. The resulting isocyanate groups can be immediately exploited for covalent immobilization of biomolecules.32... 

Generation of benzomorphan secondary amines, for conversion to appropriate N-substituted derivatives, usually requires N-demethylation of the corresponding tertiary amine. This may be effected by the von Braun reaction with cyanogen bromide or by the use of alkyl-, halogenated alkyl-, and arylchloroformates or diethylazodicarboxylate. Methods for N-demethylation in the series have been summarized by Rice.(62) Removal of an N-benzyl substituent affords an alternative path to norbenzomorphans and is exemplified by Michne and co-workers(63) and Kametani and Aoyama.(s4)... 

Method A. A high molecular weight polysaccharide was activated by reaction with cyanogen bromide at basic pH, in a similar fashion Sepharose is activated for affinity chromatography. The reaction takes place at all possible hydroxy groups to produce 0-CN randomly... 

The reaction is particularly useful for investigation of the structure of alkaloids. For example, in the study of lupinene, lupinane (1) was cleaved by reaction with cyanogen bromide in boiling benzene to a product shown to be (2) by degradation to quinolinic acid (3). ... 

Gross and Witkop found gel filtration over Sephadex G-25 invaluable for the separation of fragments resulting from the cleavage of methionine-peptide bonds in ribonuclease by reaction with cyanogen bromide. In this case 0.2 N acetic acid was used as solvent. 

Hydroxycodeinone was first represented as an a-hydroxy-ketone, but such a formulation was rejected by Gulland and Robinson [9] on account of the stability of the base towards alkaline silver and cupric solutions, and, moreover, the base does not behave as an allylamine in its reaction with cyanogen bromide [4, 13-16]. A /3-hydroxy-ketone structure was never seriously considered and is in any case at variance with the observed difficulty of dehydrating 14-hydroxycodeinone and its derivatives, but a y-hydroxy-ketone formulation is compatible with all the experimental facts. 14 Hydroxycodeinone does not show the properties of a methylene-ketone, but its dihydro-compound does, facts best explained by postulating the presence of the system —GO—0—C—C—OH in the former [9]. 

Af-Amino and lactam thiocarbonyl functions may be joined together by reaction with cyanogen bromide or by heating with an aldehyde. An AT-acylaminopyri-midine-2-thione is cyclized by heating with phosphorus oxychloride. 

Microwave irradiation can be used to make oxazolo[4,5-fc]pyridines and allows reaction with amides in lieu of acids when urea or thiomea are used, 2-ones (2-thiones) are obtained carbon disulfide with potassium hydroxide also leads to 2-thiones. The use of triphosgene and 2,3-diamino-pyridines can be used to made the analogous imidazo[4,5-b]pyridin-2-ones. Reaction with cyanogen bromide gives... 

A new photometric determination of volatile bases in tobacco and tobacco smoke in terms of nicotine, which compares quantitatively with mass spectral and g.c. methods, has been developed.27 A colorimetric method for the estimation of nicotine alkaloids in tobacco by reaction with cyanogen bromide and 4,4 -di-aminostilbene-2,2 -disulphonic acid has also been reported.28 Dilute sulphuric acid extraction of nicotine and anabasine from autopsy tissue appears to be a more efficient method than extraction with acidified ethanol, aqueous oxalic acid, and steam distillation.29 Thin-layer chromatography has been effective in the analysis of nicotine and other alkaloids and drugs.30 Two reports on the isolation of anabasine from anabasine-lupinine mixtures have appeared.31 The P a values of some nicotine-type compounds have been determined.32... 

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