[ Related Blog post: http://www.wewwchemistry.com/2013/09/the-mind-boggling-h2-chemistry ]

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Example of an Organic Synthesis Question
from a School Preliminary Examination Paper
(The question stem is highlighted in green.)
2012 Nanyang Junior College / Paper 3 / Question 1(d)
Aldehydes and ketones react with primary amines in slightly acidic solution to form
imines which have the C=N functional group. For example, propanal reacts with
methylamine to give N-methyl-1-propanimine.

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Suggest the reagents and conditions required to synthesise the following imine
derivative. Identify all the intermediate compounds.
[5]

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Proposed Solution
Step 1:
Examine the starting reagent and final product, and take note of the changes in
functional groups.

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Step 2:
Examine the structural changes in the propanal to N-methyl-1-propanimine example
given in the question stem to determine the intermediate product required to synthesise
the final product.
⇒

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Step 3:
Construct the synthetic pathway, showing clearly all reagents and conditions, and all
intermediate compounds formed.