2. Molecular Representations

Label each sulfhydryl group as primary (1°) secondary (2°) , or tertiary (3°)

Label each hydroxyl group in Assessment 13.6 as primary (1°) secondary (2°) , or tertiary (3°) 

In 2012, a group led by Professor Masayuki Satake of the University of Tokyo reported the isolation and structure determination of a toxin from a marine algal bloom that decimated the fish population off the New Zealand coast in 1998. Extensive mass spectrometry and NMR experiments ultimately led to the structure shown below, named Brevisulcenal-F. (See Journal of the American Chemical Society, 2012, 134, 4963–4968.) This structure holds the record for the largest number of fused rings, at 17.

(a) How many ether groups are present?

(b) How many alcohol groups are present? Classify the alcohols as 1° or 2° or 3°.

(c) Are there any other oxygen-containing functional groups? Which, if any?

Given the molecular formula, (i) what functional groups are possible in each of the following molecules?

(b) C₆H₁₀O

Given the molecular formula, (i) what functional groups are possible in each of the following molecules?

(a) C₆H₁₄O

Label the amines shown as a 1° amine, 2° amine, 3° amine, or 4° ammonium ion.

a.

b.

c.

d.

How many hydrogens would you expect a 24-carbon compound from each of the following molecular classes to have?

(c) Alkyne

How many hydrogens would you expect a 24-carbon compound from each of the following molecular classes to have?

(b) Alkene

How many hydrogens would you expect a 24-carbon compound from each of the following molecular classes to have?

(a) Alkane

a. How many hydrogens does an alkane with 17 carbons have?

b. How many carbons does an alkane with 74 hydrogens have?

a. How many primary carbons does each of the following compounds have?

b. How many secondary carbons does each one have?

c. How many tertiary carbons does each one have?

2.

Macrolide antibiotics all have large rings (macrocycle) in which an ester makes the ring; a cyclic ester is termed a lactone. One example is erythromycin A, first isolated from soil bacteria in the 1950s. Over time, some pathogenic bacteria have developed resistance to erythromycin by evolving an enzymatic mechanism to cleave the macrocycle at the ketone. To counter this resistance, chemists modified the erythromycin structure to replace the ketone with an amine that the bacteria could not detoxify. This modified antibiotic, azithromycin, trade name Zithromax®, is one of the most prescribed drugs in the world for respiratory infections.

(c) Identify the ketone in erythromycin targeted by bacteria as the site for detoxification.

(d) Identify the amine in azithromycin. What type of amine is it?

Draw a Lewis structure, and classify each of the following compounds:

(g) (CH₃)₃CCH₂CH₂COOH

(h)

Many naturally occurring compounds contain more than one functional group. Identify the functional groups in the ­following compounds:

a. Penicillin G is a naturally occurring antibiotic.

b. Dopamine is the neurotransmitter that is deficient in Parkinson’s disease.

Many naturally occurring compounds contain more than one functional group. Identify the functional groups in the ­following compounds:

d. Thyroxine is the principal thyroid hormone.