Dolbier HW Solutions 547

Dolbier HW Solutions 547 - 641 AMINES OCH3 OCH3 OCH3 NH2 N...

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Unformatted text preview: 641 AMINES OCH3 OCH3 OCH3 NH2 N 1. NaNO2, HCl, H2O N F BF4 2. HBF4 o-Anisidine (c) heat o-Methoxybenzenediazonium fluoroborate (57%) o-Fluoroanisole (53%) We can use the o-fluoroanisole prepared in part (b) to prepare 3-fluoro-4-methoxyacetophenone by Friedel–Crafts acylation. OCH3 OCH3 NH2 F as in part (b) OCH3 OO F CH3COCCH3 AlCl3 O o-Anisidine (d ) o-Fluoroanisole CCH3 3-Fluoro-4-methoxyacetophenone (70–80%) Remember from Section 12.16 that it is the more activating substituent that determines the regioselectivity of electrophilic aromatic substitution when an arene bears two different substituents. Methoxy is a strongly activating substituent; fluorine is slightly deactivating. Friedel–Crafts acylation takes place at the position para to the methoxy group. The o-fluoroanisole prepared in part (b) serves nicely as a precursor to 3-fluoro-4-methoxybenzonitrile via diazonium salt chemistry. OCH3 OCH3 F OCH3 NH2 CN OCH3 F F F [from part (b)] NO2 The desired sequence of reactions to carry out the synthesis is OCH3 OCH3 NH2 OCH3 F OCH3 F HNO3 as in part (b) F H2, Pt NO2 o-Anisidine o-Fluoroanisole NH2 2-Fluoro-4nitroanisole (53%) 4-Amino-2fluoroanisole (85%) 1. NaNO2, HCl, H2O 2. CuCN OCH3 F CN 3-Fluoro-4methoxybenzonitrile (46%) Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website ...
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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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