Reaction with JV-bromosuccinimide and

The benzylic position of an alkylbcnzene can be brominated by reaction with jV-bromosuccinimide, and the entire side chain can be degraded to a carboxyl group by oxidation with aqueous KMnCfy Although aromatic rings are less reactive than isolated alkene double bonds, they can be reduced to cyclohexanes by hydrogenation over a platinum or rhodium catalyst. In addition, aryl alkyl ketones are reduced to alkylbenzenes by hydrogenation over a platinum catalyst. 

The reactions of bovine a-lactalbumin with JV-bromosuccinimide and 2-hydroxy-5-nitrobenzyl bromide have led to a better understanding of the interaction of a-lactalbumin with the lactose synthase system and of the conformation of a-lactalbumin. Comparison of the properties of denatured forms of bovine a-lactalbumin and of hen egg-white lysozyme showed that different regions of the molecules unfold in response to denaturants. Amino-acid analyses confirmed that the compositions of the backbones of the two molecules are similar. 

As with chlorine-containing oxidants, JV-bromo species have been used to oxidize sulphoxides to sulphones (with no bromine incorporation) through the initial formation of a bromosulphonium ion, by nucleophilic attack of the sulphoxide sulphur atom on the electrophilic halogen atom. Such reactions involve JV-bromosuccinimide ° bromamine-T, iV-bromoacetamide ° and iV-bromobenzenesulphonamide. All reported studies were of a kinetic nature and yields were not quoted. In acid solution all oxidations occurred at or around room temperature with the nucleophilic attack on the electrophilic bromine atom being the rate-limiting step. In alkaline solution a catalyst such as osmium tetroxide is required for the reaction to proceed . ... 

Reaction of the ribofuranose ester 36 with jV-bromosuccinimide again resulted in C-4 substitution, to give the bromides 37 and 38 in the ratio of 3 2, and compound 35 and close analogs remain the only orthoamides encountered during these studies. 

Very efficient reaction occurs when phenyl 1 -thio-/ -D-glucopyranoside and -D-galactopyranoside tetrabenzoates (94 and 95) are treated in refluxing carbon tetrachloride with JV-bromosuccinimide under a heat lamp, and, within 15 minutes, they are converted into products from which the enones 96 and 97 have been obtained by direct crystallization in 76 and 83% yield, respectively (see Scheme 15).20... 

Several interesting reactions of pyrazole or pyrazolines have been noted in the literature. Efficient aromatization of l,3,5-trisubstituted-2-pyrazolines 49 to pyrazoles 50 was achieved under microwave irradiation with silica-gel supported jV-bromosuccinimide and solvent-free conditions or with bismuth(iii) nitrate pentahydrate in acetic acid <0513(65)865, 05SC2581>. 

The reaction of umbellulone (215) with JV-bromosuccinimide has been examined. Umbellulone is a hindered ketone, and Wheeler and Chung have shown that while lithium aluminium hydride in ether yields the expected mixture of the two umbellulols (216) and (217), a more bulky nucleophile like lithium tri-t-butoxyaluminium hydride leads almost exclusively to reduction of the double bond to give (218). ... 

The 4,6-O-benzylidene acetal group, which is frequently used as a protecting group in aldohexoses, can be directly transformed into 4-0-benzoyl-6-bromo derivatives by a radical-mediated cleavage reaction, and 4-0-benzyl-6-hydroxy derivatives by a reductive cleavage reaction, respectively. Por example, reaction of 2-deoxy-glucopyranoside derivative 104 with JV-bromosuccinimide (NBS) smoothly afforded 6-bromo-4-0-benzoyl derivative 105 (Scheme... 

Boron trifluoride and boron trifluoride-diethyl ether complex can be used as a source of fluoride ions in the presence of hypobromites and hypochlorites, e.g. methyl hypobromitc, tert-butyl hypobromite, methyl hypochlorite in carbon tetrachloride at 25 C. The addition of bromine monofluoride" and chlorine monofluoride" to various alkenes is accompanied by the formation of the corresponding alkoxybromides and alkoxychlorides which hinder the isolation of the halofluorinated products.57 jV-Bromo- and A -chloro-substiluted alkyl- and arylamines. -amides, and -imides, A -chloro-A,-methylamine, A -bromo-A -methylamine, A -chloro-A, /V-dimethylamine, A-bromo-A.A-dimethylamine, ACV-dichloro-A -methylamine, V,fV-dibromo-,V-mcthylaminc, A -bromosuccinimide, -V-chlorosuccinimide, Af-bromoacct-amide, A.A -dichlorourethane, can be used in the reaction instead of the hypohalites. The reactions with various alkenes conducted in dichloromethane at room temperature in the presence of boron trifluoride-diethyl ether complex produce bromofluoro and chlorofluoro addition products in 40-80 % yield. However, the reactions are complicated by the addition of A -halo-succinimides and Af.A-dichlorourcthane to the C = C bonds.58... 

A-Iodosuccinimide with primary and tertiary amines yields stable brown solutions whereas with secondary amines the colour fades in a few minutes jV-bromosuccinimide yields orange precipitates with tertiary amines - , and gives colour reactions which may be of aid in the classification of other types of amines . 

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