Ethanol and Yellow Solid Emerges

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A. Synthesis of D-Arabino-Hexulose Phenylosazone

In a 50 mL quick-fit round bottom flask with a reflux condenser, dissolve 10 g cane sugar in a mixture of 20 mL glacial acetic acid. Boil mixture for 30 minutes. Add the phenylhydrazine solution through the condenser. Remove from the hot plate. Rinse with 5 mL of 1:1 mixture of water and glacial acetic acid to complete the transfer of phenylhydrazine. When a yellow solid emerges, swirl the mixture. Wrap a dry cloth around the flask. Cool to room temperature (preferably overnight). Filter off osazone. Press and drain it. Wash with a cold mixture of 10 mL each of water and ethanol. No need to dry the product for the next step.

B. Synthesis of D-Arabino-Hexulose Phenylosotriazole

Set up: 250 mL quick-fit round bottom flask on a steam bath. Reflux the crude osazone with 35 mL ethanol. Add hot solution of 7g CuSO45H2O in 35 mL water after 30 minutes. Continue heating on the steam bath for another 30 minutes.

Filter boiling solution using 2 layers of filter paper on a large Büchner funnel. Rinse reaction flask and filtrate with little amount of boiling water. Allow filtrate to cool. Then chill it in ice. Filter off crude phenylosotriazole. Wash with water. Heat crude with 25 mL water until copper sulfate has dissolved (20-30 mins. will be adequate). Chill suspension to near 0 °C. Filter off phenylosotriazole, and wash with cold water until colorless. Press and drain it. Use 0.5 g crude for next step. Recrystallize the remainder from water (charcoal). Characterize the product using melting point analysis and IR spectroscopy.

C. Synthesis of 4-Carboxy-2-phenyl-1,2,3-osotriazole

In a 400 mL beaker on a steam bath, heat 0.5 g crude phenylosotriazole with 10 mL water. Add 1.8 g KMnO4 in 0.25 g portions with stirring. Addition takes 1.5 to 2 hours until no more frothing is observed. Heat and stir mixture for 30 minutes after each addition.

Make 20% solution of sodium metabisulfite in...
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