PART A Conditions Water Solvent

Reagents and Equipment. Weigh and place 300 mg (0.97 mmol) of erythro-2,3-dibromo-3-phenylpropanoic acid (prepared in Experiment [D2]) and 300 mg (2.1 mmol) of potassium carbonate in a 25-mL Erlenmeyer flask. Add 5 mL of distilled water. 

Reaction Conditions. Warm the mixture in a 120 °C sand bath until the solids dissolve (5-10 min) and then heat for an additional 10 min. A yellow oil should separate from the aqueous phase during this period. 

Isolation of Product. Cool the two-phase system to room temperature and, using a Pasteur pipet, transfer the contents of the flask to a 12-mL centrifuge tube. Rinse the Erlenmeyer flask with a 2-mL portion of methylene chloride, which is then transferred to the centrifuge tube. Extract the aqueous phase with the CH2Q2 rinse and foUow this extraction with two more extractions of the aqueous phase with 2-mL portions of methylene chloride. Transfer the methylene chloride extracts (the organic phase should be the lower phase, but check solubility in water to be sure) to a 25-mL Erlenmeyer flask containing enough anhydrous sodium sulfate to dry the solution. Allow the extracts to dry for about 10 min. 

Transfer a portion of the dried solution, using a Pasteur filter pipet, to a tared 5-mL conical vial containing a boiling stone. Concentrate this portion on HOOD a warm sand bath under a gentle stream of nitrogen gas in the hood. 

Now transfer the remaining dried solution to the same tared vial and concentrate as before. Finally, rinse the sodium sulfate drying agent with an additional 1-mL portion of methylene chloride, transfer it to the vial and concentrate again to yield the cfs/frans-2 -bromostyrene as a yellow oil. 

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