Q.F. Find out all the functional groups present in the following polyfunctional compounds.
a. Dopamine, a neurotransmitter that is deficient in Parkinson's disease.
b. Thyroxine, the principal thyroid hormone.
c. Penicillin G, a naturally occurring antibiotic.

Step 1. Dopamine. A catechol (benzene ring bearing two adjacent -OH groups) attached via a -CH2-CH2- chain to a primary amine (-NH2). Functional groups present: two phenolic hydroxyl groups and one primary amine group.

Step 2. Thyroxine. The principal thyroid hormone's structure carries: a carboxylic acid group (-COOH) and a primary amine group (-NH2) on its amino-acid-like side chain, a free phenolic -OH on one of its two aromatic rings, an ether (-O-) linkage joining its two iodinated benzene rings together (a diaryl ether), and several aryl-halide (carbon-iodine, i.e. iodo, -I) substituents on those rings. …

Recognising each functional group's characteristic bonding pattern (Table 14.3) within the well-known, standard stru …

• Missing that a polyfunctional natural product can carry several DIFFERENT instances of a group family, or several DIFFERENT families side by side, rather than just one. …