Conjugate addition - Dimedone synthesis - …

A simple, two-step synthesis of 9-phenylxanthene-1,8-dione from dimedone and benzaldehyde was developed for second-semester undergraduate organic chemistry. Both reactions afford crystalline solids in excellent yield by simply precipitating the product from solution. Reaction times are very short, and no specialized equipment, reagents, or purification techniques are needed. Multiple spectroscopic methods (IR and 1H, 13C, and DEPT NMR) are employed to solve the structures of the intermediate and final product, which are unknown to students. The products are not ones students would initially predict, but rather are derived from careful analysis of the spectroscopic data in conjunction with logical mechanistic steps. 1H NMR peaks are well resolved, even at low field. Students have responded favorably over the five years this experiment has been used as a culminating experience in organic chemistry lab.

Dimedone supplier | CasNO.126-81-8
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In this experiment, the synthesis of 5,5- (trivialname: dimedone) will be carried out. The synthesis is actually a modification of thenormal Robinson annulation, in that initial Michael addition of diethyl malonate withmesityl oxide (4-methylpent-3-en-2-one) is followed by an intramolecular Claisencondensation rather than aldol condensation. The annulation product is hydrolysed anddecarboxylated to yield the cyclic 1,3-diketone (Eqn.2).


Synthesis of Dimedone and Measuring of Its …

Dimedone | C8H12O2 | ChemSpider
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This course will involve a substantial amount of writing. For each person there will be several lab reports done in the complete formal scientific style outlined in the lab text and several other less formal written reports or lab information worksheets. In addition there may be work done in groups and oral presentations. You are expected to keep a proper laboratory notebook record of all your work in lab. Before each lab experiment you are expected to read the experiment background information and related techniques and to prepare a written prelab section in your notebook containing: the statement of the problem, your approach to the problem and an overview of your experiment, appropriate reactions, structures of compounds, physical properties, and safety information. There may be additional prelab questions. Some of this information you will be expected to locate in reference sources (books and the Internet).