Chemistry Problem Solving: Determining Structures and Stereochemistry, Slides of Organic Chemistry

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Unit I - Structure

Problems

Determine the structure from the spectra below.

Problem 2

• Butaclamol is an antipsychotic used in the

treatment of schizophrenia. How many

stereocenters does it have?

N

OH

C(CH 3 ) 3

Problem 2 Solution

N

OH

C(CH 3 ) 3

Nitrogen has potential to be stereogenic, but converts rapidlyat room temperature as sp3 and sp2 are close in energy

Problem 3 Solution

H

H

Cl

Cl

H

Cl

H

Cl

H

Cl

H

Cl

H

Cl

Cl H

H CH CH 3 CH (^2) CH 3 2 OH

CH 3 CH

H CH 2 OH 2 CH 3

CH 3 Cl H H 3 C H CH 2 CH 3

CH 2 CH 3 H CH 3 H Cl CH 3

Constitutional Diastereomers

Enantiomers Identical

Problem 4

• Provide systematic (IUPAC) names for the

following structures

CH 2 CH 3 H CH 3 H Cl CH 3

H 3 C

H

CH 2 CHCH 3

H

OH

Problem 5

• Draw the most stable conformation of:

– Butane

– Cis-1,2-dimethylcyclohexane

Problem 5 Solution

• Butane

• Cis-1,2-dimethylcyclohexane

CH 3

H CH^3 H H H^ OR^ H

H H

H H

H H H

H H

H H

CH 3 H H

H H

H H

H

H

CH 3 If you draw both methyl groupsequatorial, it will be trans, so this isthe best you can do for this structure

Problem 6 Solution

– Is the unknown colorless liquid (2R)-2-pentanol?

– Not necessarily

– Why or why not? – Both enantiomers have

identical physical properties

– If not, what else could it be and how could you

distinguish the two? – it could be (2S)-2-pentanol,

and optical rotation (or odor possibly) could

distinguish the two H OH