Which one of the following nitro-compounds does not react with nitrous acid?
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Answer
(3) [figure]
Solution
Nitrous acid reacts with a nitroalkane only through the α-hydrogen (H on the carbon bearing -NO2):
1° nitroalkane (RCH2NO2, two α-H) nitrolic acid, RC(NO2)=NOH
2° nitroalkane (R2CHNO2, one α-H) pseudonitrole, R2C(NO)NO2
3° nitroalkane (R3CNO2, no α-H) no reaction
(1) CH3CH2CH2NO2 – 1°, two α-H, reacts.
(2) (CH3)2CHCH2NO2 – 1°, two α-H, reacts.
(3) (CH3)3C-NO2 – 3°, no α-H, does not react.
(4) CH3COCH(CH3)NO2 – 2°, one α-H, reacts.
2-Methyl-2-nitropropane does not react with nitrous acid.
Answer: (3)