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🥼organic chemistry review

4-aminobenzoic acid

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

4-aminobenzoic acid, also known as PABA, is an organic compound that consists of a benzene ring with a carboxyl group and an amino group attached at the 4-position. It is an important precursor in the synthesis of various pharmaceuticals and is also found naturally in some foods.

5 Must Know Facts For Your Next Test

  1. 4-aminobenzoic acid is a white, crystalline solid that is soluble in water and alcohol.
  2. It is an essential nutrient and a precursor for the synthesis of folic acid, which is important for cell growth and development.
  3. 4-aminobenzoic acid is used in the production of various pharmaceuticals, such as sulfa drugs, and is also used as a UV-absorbing agent in sunscreens.
  4. The amino group on 4-aminobenzoic acid can be further functionalized, allowing for the synthesis of a wide range of derivatives.
  5. 4-aminobenzoic acid is found naturally in some foods, such as liver, mushrooms, and some fermented products.

Review Questions

  • Explain the significance of the amino and carboxyl functional groups in the structure of 4-aminobenzoic acid.
    • The amino group (-NH2) and the carboxyl group (-COOH) in the structure of 4-aminobenzoic acid are both important functional groups that contribute to its chemical properties and reactivity. The amino group can participate in various reactions, such as acylation and alkylation, while the carboxyl group gives the compound acidic properties and allows it to form salts and esters. The combination of these functional groups makes 4-aminobenzoic acid a versatile building block in the synthesis of various pharmaceuticals and other important compounds.
  • Describe the role of 4-aminobenzoic acid as a precursor for the synthesis of folic acid.
    • 4-aminobenzoic acid is an essential precursor in the biosynthesis of folic acid, also known as vitamin B9. Folic acid is a crucial nutrient required for cell growth and development, as it plays a key role in the synthesis of DNA and RNA. The amino group of 4-aminobenzoic acid is used in the condensation reaction with other precursors, such as pteridine and glutamic acid, to form the complete folic acid molecule. This highlights the importance of 4-aminobenzoic acid in maintaining proper cellular function and overall health.
  • Analyze the potential applications of 4-aminobenzoic acid in the pharmaceutical industry and its use as a UV-absorbing agent in sunscreens.
    • 4-aminobenzoic acid has numerous applications in the pharmaceutical industry due to its versatile chemical structure. Its amino and carboxyl groups allow for the synthesis of a wide range of derivatives, including sulfa drugs, which are important antimicrobial agents. Additionally, the aromatic nature of the benzene ring and the presence of the amino group make 4-aminobenzoic acid an effective UV-absorbing agent, allowing it to be used in sunscreens to protect the skin from harmful ultraviolet radiation. The combination of its pharmaceutical and cosmetic applications highlights the diverse utility of 4-aminobenzoic acid as a valuable organic compound.