With Hydrogen Bromide

Sketch a potential energy diagram for the reaction of 1 heptanol with hydrogen bromide paying careful attention to the positioning and structures of the intermediates and transition states... 

Butanol and 2 butanol are converted to their corresponding bromides on being heated with hydrogen bromide Write a suitable mechanism for each reaction and assign each the appropriate symbol (SnI or Sn2)... 

Bromination of methane is exothermic but less exothermic than chlorination The value calculated from bond dissociation energies is AH° = -30 kJ Al though bromination of methane is energetically fa vorable economic considerations cause most of the methyl bromide prepared commercially to be made from methanol by reaction with hydrogen bromide... 

Reaction of alcohols with phosphorus tribromide (Section 4 13) As an alternative to converting alco hols to alkyl bromides with hydrogen bromide the inorganic reagent phosphorus tribromide is some times used... 

Select the compound in each of the following pairs that will be converted to the corre spending alkyl bromide more rapidly on being treated with hydrogen bromide Explain the reason for your choice... 

Two stereoisomers of 1 bromo 4 methylcyclohexane are formed when trans 4 methyl cyclohexanol reacts with hydrogen bromide Write structural formulas or make molecular mod els of... 

Kharasch s earliest studies in this area were carried out in collab oration with graduate student Frank R Mayo Mayo performed over 400 experi ments in which allyl bromide (3 bromo 1 propene) was treated with hydrogen bromide under a variety of conditions and determined the distribution of the normal and abnormal products formed during the reaction What two prod ucts were formed Which is the product of addition in accordance with Markovmkovs rule Which one corresponds to addition opposite to the rule ... 

Two different compounds having the molecular formula CgHi5Br are formed when 1 6 dimethylcyclohexene reacts with hydrogen bromide in the dark and in the absence of peroxides The same two compounds are formed from 1 2 dimethylcyclohexene What are these two compounds ... 

When a reactant is chiral but optically inactive because it is racemic any products derived from its reactions with optically inactive reagents will be optically inactive For example 2 butanol is chiral and may be converted with hydrogen bromide to 2 bromo butane which is also chiral If racemic 2 butanol is used each enantiomer will react at the same rate with the achiral reagent Whatever happens to (/ ) (—) 2 butanol is mir rored m a corresponding reaction of (5) (+) 2 butanol and a racemic optically inactive product results... 

FIGURE 16 4 The mechanism for the cleavage of ethers by hydrogen halides using the reac tion of diethyl ether with hydrogen bromide as an example... 

Alternatively the benzyloxycarbonyl protecting group may be removed by treat ment with hydrogen bromide m acetic acid... 

Step n When the peptide is completely assembled it is removed from the resin by treatment with hydrogen bromide m trifluoroacetic acid... 

Substitution reactions on dialkyl peroxides without concurrent peroxide cleavage have been reported, eg, the nitration of dicumyl peroxide (44), and the chlorination of di-/ fZ-butyl peroxide (77). Bromination by nucleophilic displacement on a-chloro- or a-hydroxyalkyl peroxides with hydrogen bromide produces a-bromoalkyl peroxides (78). 

Linear alpha-olefins are the source of the largest volume of ahphatic amine oxides. The olefin reacts with hydrogen bromide in the presence of peroxide catalyst, to yield primary alkyl bromide, which then reacts with dimethylamine to yield the corresponding alkyl dimethyl amine. Fatty alcohols and fatty acids are also used to produce amine oxides (Fig. 1). 

Polypeptide Synthesis and Analysis. Sihca or controUed-pore glass supports treated with (chloromethyl)phenylethyltrimethoxysilane [68128-25-6] or its derivatives are replacing chloromethylated styrene—divinylbenzene (Merrifield resin) as supports in polypeptide synthesis. The sdylated support reacts with the triethyl ammonium salt of a protected amino acid. Once the initial amino acid residue has been coupled to the support, a variety of peptide synthesis methods can be used (34). At the completion of synthesis, the anchored peptide is separated from the support with hydrogen bromide in acetic acid (see Protein engineering Proteins). 

Chemical Properties. Thionyl chloride chemistry has been reviewed (169—173). Significant inorganic reactions of thionyl chloride include its reactions with sulfur trioxide to form pyrosulfuryl chloride and with hydrogen bromide to form thionyl bromide [507-16-4]. With many metal oxides it forms the corresponding metal chloride plus sulfur dioxide and therefore affords a convenient means for preparing anhydrous metal chlorides. 

The high reactivity of pyrroles to electrophiles is similar to that of arylamines and is a reflection of the mesomeric release of electrons from nitrogen to ring carbons. Reactions with electrophilic reagents may result in addition rather than substitution. Thus furan reacts with acetyl nitrate to give a 2,5-adduct (33) and in a similar fashion an adduct (34) is obtained from the reaction of ethyl vinyl ether with hydrogen bromide. 

The hydrolysis of 2-adamantanecarbonitrile with hydrogen bromide in acetic acid provides a useful route to 2-adamantanecarboxylic acid (m.p. 143-144°), which the submitters obtained in 95% yield. Stetter and Tillmans reported a yield of 62% starting with impure 2-adaman-tanecarbonitrile. 

When strychnine is treated with hydrogen bromide and red phosphorus in boiling acetic acid, it is converted into a complex bromodeoxyiso-strychnine hydrobromide, (C2iH2iON2Br)a , which is hydrolysed by boiling N-sulphuric acid to isostrychnine (see above), now distinguished as I, and fsostrychnine-II, m.p. 218-9°, — 258° (EtOH), which with acetic... 

Perfluoroalkylsulfonyl chlorides are efficiently converted to the corresponding perfluoroalkyl bromides with hydrogen bromide and a catalyst [55] (equation 38)... 

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