Preparation of 1-Phenyl-3-Phenylaminopyrrolidine-2,5-Dione an Organic Laboratory Experiment on the Michael Addition

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Preparation of
1-Phenyl-3-phenylaminopyrrolidine-2,5-dione
An Organic Laboratory Experiment on the Michael Addition
Ram N. Ram1 and Kiran Varsha
Indian Institute of Technology, Delhl Hauz Khas, New Delhl-110016, India

The Michael Addition is one of the important synthetic
methods for the preparation of 1,3- and 1,5-difunctionalized compounds ( I ) . Virtually all undergraduate organic chemistry textbooks use a consideration of the Michael addition, hut few suitable laboratory experiments have been puhlished on this subject to supplement the lectures. Most of the reported procedures (2) suffer from one or more of the following disadvantages-long reaction time ranging from several hours to days, lengthy product isolation and purification procedures, and the highly toxic Michael-acceptor. Presnmably because of these reasons, most of the modern lahoratory manuals are found short of an experiment on the Michael

addition. (3).
We describe, herein, a two-step laboratory experiment
involving the Michael addition of aniline as one of the steps. The first step involves the acylation of aniline with maleic anhydride to give maleanilic acid 1. I n the second step maleanilic acid undergoes the Michael addition of aniline and cyclization to yield I-phenyl-3-pl~enylaminopyrrolidine-2,5dione 2 (Method A). Compound 2 can also he obtained in one step by using commercially available maleanilic acid

(Merck) or, albeit in slightly lower overall yield, by refluxing maleic anhydride and aniline in 12molar ratio in acetic acid (Method B) (Fig. 1). The experiment is operationally simple, requiring simply manual stirring, filtration, and recrystallization, readily available inexpensive reagents, and short reaction time. Thus, it is ideally suited to the students. The NMR and IR spectra of the compound 2 may he used to

illustrate the geminal and vicinal couplings along with the
effect of the dihedral angle on the latter (Fig. 2) and the
coupled vibrations of the imide...
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