Organic 2 Review Problem 355

Organic 2 Review Problem 355 - REACTIONS AND IDENTIFICATION...

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REACTIONS AND IDENTIFICATION 339 p-Nitrobenzoyl derivatives can be prepared as in (a) or ( b ) above. If direct shaking, as in (a), is employed, the p -nitrobenzoyl chloride should first be finely powdered. Alternatively, dissolve the phenol in dry pyridine, add the p -nitrobenzoyl chloride and boil gently under reflux for 20 minutes. Cool and pour into dil. HCl. Collect the pre- cipitate and stir it thoroughly with dil. Na 2 CO 3 solution to ensure removal of p -nitrobenzoic acid: filter off the residue, wash it with water and recrystallise. (This method can sometimes be profitably used for 3,5-dinitrobenzoylation.) (M.ps., p. 538.) 5. Urethane formation. See (C) below. This reaction should be used for crystalline derivative formation, and not as a general reaction for phenols. 6. Azo-dye formation. Dissolve 2-3 drops of aniline in i ml. of cone. HCl and add 3 ml. of water. Shake to dissolve any hydrochloride which may have separated and cool in ice. Add a few drops of 20% sodium nitrite solution. Add this cold diazonium solution to a cold
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

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