Question
Naproxen belongs to a class of pharmaceuticals referred to as non-steroidal anti-inflammatory drugs or NSAIDS. For Naproxen, the (S)-(+)-enantiomer is the desired pharmacological activity while the (R)-(-)-enantiomer is potentially a liver toxin. Due to this, commercial Naproxen in sold as the (S)-(+)-enantiomer with high levels of optical purity. "Calculate the observed rotation, alpha for naproxen from the following information: %S = 90% [alpha] literature = +66.0 concentration = 20g/78mL path length = 2 dm
Explanation / Answer
GIven specific rotation for S enantiomer = 66
For R enantiomer = -66
alpha literature means specific rotation ??? THen
Observed rotation = Fraction of S * 66 + Fraction of R * -66
Observed rotation = 66*0.9 + 0.4*-34 = +52.8