I know it will have a CC (triple bond) with a -OH or -NH2 secondary, but I don’t know how to configure it
According to the nitrogen rule, the mass of 71 would indicate an odd number of nitrogens (1, 3…). If we consider the IR absorption at 3200 (strong, broad) to be NH2 (mass = 16), we can find a putative molecular formula:
71 – 16 = 55
57/12 = 4.58; therefore, we assume that there are 4 carbons present.
55 – 48 = 7
This would therefore indicate that there are 7 hydrogens present, so the putative molecular formula is
C4H9N
or C4H7NH2
It looks like your question was cut off, so there’s probably some additional information that would be helpful for us to narrow down possible structures.
I’m afraid the doctor doesn’t have the answer. However, the user also failed to provide all the information needed to fix this issue…
First, we know for a fact that there is a nitrogen there, since the molecular mass is odd.
we also know that a broadband at 3200 means an NH or an OH, we will come back to this. A high bandwidth at 2250 is a good indicator of a nitrile group.
What has been left out are the 2 NMR signals at about 240. These signals are for 2H and have tertiary multiplicity. This means you have two CH2 groups that have 2 hydrogen neighbors. To me, this indicates that the CH2s are neighbors.
Combine both CH2 and nitrile – Molecular weight totals 55
71-55=16
Now we’re back off the peak at 3200, we know that’s an OH or NH.
Weight OH = 16
NH weight = 15
OH is the only one that adds up to 71, add the OH to the other CH2 and you get:
N:::C:CH2:CH2:OH
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