(Chemical Connections 4E) (a) Review the structural formulas for lycopene (Problem 3.6...

(Chemical Connections 4E)

(a) Review the structural formulas for lycopene (Problem 3.63) and b-carotene (Problem 8.40), two natural food-coloring agents, and compare their structural formulas with those of Allura Red and Sunset Yellow.

(b) What structural feature or features do these four compounds have in common that might account for the fact that each is colored?

(c) Why are these two food and cosmetic dyes soluble in water while lycopene and b-carotene are not?

Problem 3.63

(Chemical Connections 3C) In which isomer of retinal is the end-to-end distance longer, the all-trans isomer or the 11-cis isomer?

Problem 8.40

(Chemical Connections 8C) Is Librium chiral? Is Valium chiral?