Chemistry 251 Laboratory -- Spring 2000
Chrysanthemic Project Home Page

Index

• 1999 Chrysanthemic Acid Synthesis Home Page
• Students working on this project
• Table of Reagents and Amounts Available
• Alternate Diene Synthesis

Chrysanthemic Acid, from the chrysanthemum flower, is a natural insecticide which has been known since ancient Persia. Its structure is that of a cyclopropane containing, irregular, monoterpene. Last year, most of the groups working on the synthesis of chrysanthemic acid were attempting to use the procedure described by Schatz in the J. Chem. Ed. article cited above, but were having trouble getting one of the reactions to work. One group found the procedure of Kelly to work fairly well. In this procedure the diene shown below was transformed in two steps to Chrysanthemic acid. Since Aldrich is discontinuing production of this diene, we need to find a method for preparing it. Preliminary studies suggest that dehydration of the diol shown below might be an effective method, but it needs some more work. In addition, this synthesis gives mixture of cis and trans isomers, and it would be useful to explore methods to improve the trans/cis ratio.

The table below lists the chemicals that we will have available for this project. If you need something that is not on this list, consult with the mentor for your project. Also note the "Amount/group" column. This is the total amount of material available for each group to use on the project.

Reagent	Source	Amount/group	Location	Comments
2,5-dimethyl-2,5-hexanediol	Aldrich Cat. # 14,361-8	15 g	TA room
Ethyl diazoacetate	Fluka Cat. # 33501	5 mL	TA room
2,5-dimethyl-2,5-hexadiene	Aldrich	1 mL	TA room	Aldrich no longer makes this, but we may have a small amount available from last year.
4-Bromo-2-methyl-2-butene	Aldrich Cat. # 27,437-2	2 g	TA room
Triphenylphosphine	Aldrich Cat. # T8,440-9	10 g	TA room

Alternate Diene Synthesis

1. Some groups are investigating an alternate synthesis of the diene as shown above.