Chem 334 - Summer 1998 - Organic Chemistry I
Dr. Carl C. Wamser Dr. Carl C. WamserVollhardt & Schore, pp 169 - 174
Problems 1 , 3 , 4 , 5 , 7 , 8 , 9 , 11 , 12 , 13 , 14 , 18 , 19
1. The specific rotation of cholesterol is [alpha] = +39° .
What observed rotation, alpha , would be expected for each of the following solutions, using a standard 10 cm cell ?
a) pure (-)-cholesterol at a concentration of 0.1 g/mL
- 3.9°
b) a mixture of 0.1 g/mL (+)-cholesterol and 0.1 g/mL (-)-cholesterol
0° (racemic)
c) a mixture made from 5 mL of solution a and 5 mL of solution b
- 1.95°
2. Most of the naturally-occurring amino acids are chiral, having the (S) configuration. Write good structures for the (S) configuration of each of the following amino acids.
a) alanine CH3CH(NH2)COOH
b) lysine CH3CH2CH2CH2CH(NH2)COOH
c) aspartic acid HOOCCH(NH2)CH2COOH
d) cysteine HSCH2CH(NH2)COOH
(Note - the natural structure is actually (R))
