Malonic ester synthesis
Ethyl malonate is called as malonic ester.
Synthesis of wide variety of organic compounds starting from malonic ester is called malonic ester synthesis. Malonic ester synthesis involves following steps:
Step I : The α-hydrogen in malonic ester are acidic. When malonic ester is treated with a strong base such as sodium ethoxide, it is converted into salt, known as sodiomalonic ester.
Step II : The carbanion present in sodiomalonic ester is a nucleophile and therefore this step involves nucleophilic attack on the alkyl halide by the carbanion to give monoalkylmalonic ester.
The monoalkyl malonic ester have one acidic hydrogen, so it can be alkylate again using same or different alkyl halides to get dialkylmalonic ester.
Step III : The mono- or dialkylmalonic ester thus formed can be hydrolysed to give a mono or dialkylmalonic acid. These acids undergo decarboxylation easily to form mono- or disubstituted acetic acid.
Examples of malonic ester synthesis
⊗ Synthesis of 2-methylpentanoc acid by malonic ester synthesis
Structure of 2-methylpentanoic acid is:
2-methylpentanoic acid can be synthesized from malonic ester by following reaction mechanism:
Q) Outline the synthesis of pentanoic acid from malonic ester.
Structure of pentanoic acid is:
Pentanoic acid can be synthesized from malonic ester by following reaction mechanism:
Q) Outline the synthesis of 4-methyl pentanoic acid from malonic ester.
Structure of 4-methyl pentanoic acid is:
4-methyl pentanoic acid can be synthesized from malonic ester by following reaction mechanism:
Q) Outline the synthesis of 2-ethyl heptanoic acid from malonic ester.
Structure of 2-ethylheptanoic acid is:
2-ethylheptanoic acid can be synthesized from malonic ester by following reaction mechanism:
Q) Outline the synthesis of cyclobutane carboxylic acid from malonic ester.
Structure of cyclobutane carboxylic acid is:
Cyclobutane carboxylic acid can be synthesized from malonic ester by following reaction mechanism:
References
- Ghosh, S.K., Advanced General Organic Chemistry, Second Edition, New Central Book Agency Pvt. Ltd., Kolkatta, 2007.
- Morrison, R.T. , Boyd, R.N., Organic Chemistry, Sixth edition, Prentice-Hall of India Pvt. Ltd., 2008.
- March, j., Advanced Organic Chemistry, Fourth edition, Wiley Eastern Ltd. India, 2005.
