Show how you would synthesize any of the standard amino acids from each starting material. You may use any necessary reagents.
(b)

Verified step by step guidance

1. Step 1: Analyze the starting material. The given compound is isobutyric acid (2-methylpropanoic acid), which contains a carboxylic acid functional group. This will serve as the precursor for the amino acid synthesis.
2. Step 2: Convert the carboxylic acid group into an α-bromo acid. Use bromine (Br2) and phosphorus tribromide (PBr3) in the presence of a solvent like acetic acid to perform the Hell-Volhard-Zelinsky reaction. This introduces a bromine atom at the α-carbon adjacent to the carboxylic acid group.
3. Step 3: Replace the bromine atom with an amino group (-NH2). Treat the α-bromo acid with excess ammonia (NH3) in a solvent like ethanol or water. This substitution reaction yields the corresponding α-amino acid.
4. Step 4: Purify the product. The resulting compound is an amino acid, specifically valine, which has both an amino group and a carboxylic acid group. Purify the product using recrystallization or other appropriate techniques.
5. Step 5: Verify the structure of the synthesized amino acid. Use spectroscopic methods such as NMR (nuclear magnetic resonance) and IR (infrared spectroscopy) to confirm the presence of the amino group and carboxylic acid group, ensuring the synthesis was successful.

Key Concepts

Amino Acid Structure

Amino acids are organic compounds characterized by a central carbon atom bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain (R group). The R group determines the specific properties and identity of the amino acid, influencing its role in protein synthesis and function.

Synthesis of Amino Acids

The synthesis of amino acids often involves the formation of the amino and carboxyl functional groups from suitable starting materials. Common methods include the Strecker synthesis, which uses aldehydes, ammonium chloride, and cyanide, and the Gabriel synthesis, which employs phthalimide and alkyl halides to introduce the amino group.

Reagents in Organic Synthesis

Reagents are substances used in chemical reactions to facilitate the transformation of reactants into products. In amino acid synthesis, reagents such as acids, bases, and coupling agents are crucial for forming peptide bonds and modifying functional groups, enabling the construction of the amino acid structure from simpler precursors.