Bromine atomic purification

Without purification, sulfoxides 67 were heated in toluene in the presence of NaHC03 to give elimination product 68 along with a saturated ketone 69 in 76% and 17% isolated yields, respectively. On the other hand, the same transformation using PhSeNa, instead of PhSNa, provided 68 as the sole product in 72% from 65. Finally, treatment of 68 with LiAlH4 reduced the ethylcarbamate function and removed the C-l bromine atom to afford codeine. 

Reduction of triarylbismuth dihalides to the parent triarylbismuthines can be performed by using a variety of reducing agents, which include hydrazine hydrate, sodium hydrosulfite, liquid ammonia, LiAlH4, NaBH4, sodium sulfide and sodium dialkyldithiocarbamate. This type of reduction has been used for the purification of tris(3-methylphenyl)bismuthine which is purified with difficulty in the trivalent state [26JA507]. The electrolytic reduction of triphenyl-bismuth dibromide has been found to be a one-step, two-electron process where the bromine atoms are released as bromide ions [66JA467]. 

The addition reaction of an alkene with a halogen like bromine or chlorine gives a vicinal dihalide. The halogen molecule is split and the halogens are added to each end of the double bond (Following fig.). Vicinal dibromides are quite useful in the purification or protection of alkenes since the bromine atoms can be removed under different reaction conditions to restore the alkene. Vicinal dibromides can also be converted to alk5mes. 

In the conversion, the chlorine atom is replaced by bromine. Since the yield is neatly quantitative (90-95%), the bromination product is often used without purification to avoid losses by decomposition. ... 

The dibromides are often used for the purification of olefins since the double bond is easily regenerated by zinc and alcohol treatment. Compounds of the type RR CHCHBrCHBrR", where R" is an alkyl group or a hydrogen atom are prepared directly from the corresponding tertiary alcohols. Under the conditions of bromination, simultaneous dehydration and addition occurs e.g., Namyl alcohol to ttimethylethylene dibromide (70%). ... 

Introducing the fluorine atom via an electrophilic fluorination reagent requires a two-stage bromination and low-temperature metalation procedure that is followed by a chromatographic purification. 

Succinic acid per se does not represent a large volume consumer of MA. However, it finds a variety of uses in chemical applications. Its most important derivative widely known to synthetic organic chemists is N-bromosuccinimide 5. The latter is used as a selective brominating agent.The active halogen atom can also be supplied using N-chlorosuccinimide for purification of drinking water. 

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