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39 b) p ‑aminobenzoic acid: (anesthesin and novocaine). How are they used in medicine? 6. Write a scheme for the preparation of n ‑aminophenol derivatives having a medicinal value: a) ethyl ester of p‑aminophenol (phenetidine); b) ethyl ester of N‑acetyl- p ‑aminophenol (phenacetin); c) n ‑acetaminophenol (paracetamol). 7. Write the structure of the simplest sulfanilamide drug streptocide. Explain the mechanism of antibacterial action of sulfanilamide preparations. Laboratory work Experiment 1. Proof of the presence of hydroxyl groups in tartaric acid. Place two drops of 2% solution of CuSO 4  and 10% NaOH solution in two test tubes. A blue Cu (OH) 2  precipitate will appear. Add a solution of potassium tartratein the first test tube. The precipitate dissolves to form a blue solution. Liquids heat to boilingin both test tubes. The color of the liquid does not changein the first test tube, in the second – the blue precipitate turns into copper (II) oxide of black color. The resulting blue solution is called the Felling Reagent and is used to detect glucose in the urine. The reaction equation with copper hydroxide (II): COOK HC HC OH OH COOK 2 + Cu(OH) 2 COOK HC HC O O COOK COOK CH CH O O COOK Cu H H + 2H 2 O Experiment 2. Detection of acid properties of acetoacetic ether. Mix 2–3 ml with 1 drop of phenolphthalein in a test tube and add 1 drop of 2N NaOH solution. The solution will turn red. Add 2–3 drops of acetoacetic ether, mix thoroughly – the color will disappear. Explain what is happening. Write the equation of keto-enol equilibrium for acetoacetic ether. Disappearance of the color of the indicator occurs due to neutralization of alkali: + H 2 O CH 3 C CH OH COOC 2 H 5 + NaOH CH 3 C CH ONa COOC 2 H 5 Experiment 3. Proof of the presence of phenolic hydroxyl in salicylic acid. Place several crystals of salicylic acid in the tube, add 3–4 drops of water, and then 1 drop of 1% solution of FeCl 3. What are you watching? What are the