a) The prefix R and S stand for Rectus and Sinister respectively.
b) Define enantiomer. Give one example.
Stereoisomers whose molecules are non superposable mirror images of each other. Enantiomers have identical physical & chemical properties (e.g. melting point, boiling point, refractive index, solubility etc.)
Except 1) The direction of rotation of the plane of plane polarized light and
2) How they react with optically active reagents. e.g. Enzyme, Taste buds, scent
Example:- (+)-limonene has smell of oranges and (-)-limonene smells like lemons.
c) Give one example of each of linear and
non linear tricyclic aromatic system.
Anthracene and Phenanthrene
d) Give IUPAC name to following bridgehead
compounds
e) Give the end product of willgerodt reaction and DCC oxidation.
f) Write reaction for Wolff
rearrangement.
The Wolff rearrangement is an organic reaction used
to convert an α-diazo ketone to a ketene using a uv light, or thermal
conditions. The mechanism of the Wolff rearrangement is essentially one step
which is initiated by the catalyst. The reaction involves a 1,2-shift to form
the ketene product and release a molecule of nitrogen gas.
g) What is meso compound? Give one example
Compound which contain at least two chiral centers
but optically inactive called meso stereoisomers. A meso compound is one whose
molecules are superimposable on their mirror images even though they contain
chiral centers.
Example:- 2,3-dihydroxybutanedioic acid [ tartaric acid
]
