Concept explainers
Interpretation:
How to synthesize from the malonic ester the dialkylated intermediate required for the synthesis of aprobarbitol is to be shown. Further a mechanism for the reaction of the intermediate with urea to give aprobarbitol is to be proposed.
Concept introduction:
Removal of both the hydrogens of the active methylene group in malonic ester by treating with LDA and then treating the enolate ions with
The steps involved in the reaction of the dialkylated product with urea are i) Nucleophilic attack of nitrogen of urea on the carbonyl carbon of the dialkylated ester ii) Elimination of the ethanol iii) Another nucleophilic attack by second nitrogen of urea on the carbonyl of the other ester group iv) Elimination of another ethanol.
To state:
How to synthesize from the malonic ester the dialkylated intermediate required for the synthesis of aprobarbitol. Further to propose a mechanism for the reaction of the intermediate with urea to give aprobarbitol
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Chapter 22 Solutions
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- Barbiturates are prepared by treatment of diethyl malonate or a derivative of diethyl malonate with urea in the presence of sodium ethoxide as a catalyst. Following is an equation for the preparation of barbital, a long-duration hypnotic and sedative, from diethyl diethylmalonate an urea. Barbital is prescribed under one of a dozen or more trade names. Propose a mechanism for This reaction The pKa of barbital is 7.4. Which is the most acidic hydrogen in this molecule and how do you account for its acidity?arrow_forwardHow imines and enamines are converted back to carbonyl compounds by hydrolysis with mild acid ?arrow_forwardThe Stork reaction is a condensation reaction between an enamine donor and an α,β-unsaturated carbonyl acceptor. The overall reaction consists of a three-step sequence of formation of an enamine from a ketone, Michael addition to an α,β-unsaturated carbonyl compound, and hydrolysis of the enamine in dilute acid to regenerate the ketone. Consider the Stork reaction between acetophenone and 3-buten-2-one. Draw the structure of the product of the enamine formed between acetophenone and pyrrolidine. Draw the structure of the Michael addition product. Draw the structure of the final product.arrow_forward
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- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning