Isosafrole or Propenylbenzene From Grignard Reagent
solution is refluxed for 30 minutes. The solution is hydrolyzed with ammonium chloride just like safrole was and then isolated just the same to give an -hydroxy intermediate (please don't ask, but the yield is 81%).
What the chemist has is an alcohol intermediate which is not what she wants. If she were to flick off that OH group then a double bond will form in its place and isosafrole or propenylbenzene will be borne , So what the evil chemist does is place 60g of the alcohol intermediate oil and 1g potassium bisulfate (KHS04) into a really small flask, attach the flask to a distillation apparatus and start heating with vacuum. As the OH group is being kicked out it will form water, which the chemist will see distilling over. When no more water can be seen evolving then the reaction is finished. However, the chemist continues to heat to distill over all of the isosafrole which will smell just like licorice (yield=91% from the intermediate). If the chemist wanted to she could perform the same bisulfate procedure in a beaker or flask without the distillation setup and stop the reaction when a temperature of 170°C has been reached [28 p698]. The oil is still going to have to be distilled to purify it though.
To make isosafrole or propenylbenzene the chemist will do exactly what was done for piperonal except that the chemical in three-neck flask is going to be 30g of propanal chilled to -15°C. The addition is the same except that after the solution reaches room temperature, the ice tray is removed, heat is applied and the
Continue reading here: Chloromethylation
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