Dolbier HW Solutions 572

Dolbier HW Solutions 572 - 666 ARYL HALIDES nucleophilic...

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nucleophilic aromatic substitution of both chlorines is possible but leads to a compound with the wrong molecular formula (C 6 H 7 N 3 O 2 ). To obtain a f nal product with the correct molecular formula, the original nitration reaction must lead not to a mononitro but to a dinitro derivative. This is reasonable in view of the fact that this reaction is carried out at elevated temperature (120 ° C). This two-step sequence has been carried out with product yields of 70 71% in the f rst step and 88 95% in the second step. ( d ) This problem also involves two transformations, nitration and nucleophilic aromatic substitu- tion. Nitration will take place ortho to chlorine (meta to tri F uoromethyl). ( e ) The primary alkyl halide is more reactive toward nucleophilic substitution than the aryl halide. A phosphonium salt forms by an S N 2 process. ( f ) N -Bromosuccinimide (NBS) is a reagent used to substitute benzylic and allylic hydrogens with bromine. The benzylic bromide undergoes S N 2 substitution with the nucleophile,
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This note was uploaded on 10/03/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.

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