Question

a. Prepare n-butylamine by Gabriel synthesis .
b. Which of the following cannot be prepared by Gabriel methaod from their corresponding halides or tosylates .
I. t-Butylamine , II . Neopentylamine ,
III. Diethylamine , IV. P-Toluidine ,
V. m-Nitroaniline ,
Vi. Vinylamine , VII. p-Nitroaniline , VIII. o-Nitroaniline , and XI. Allylamine .

Answer 1

a.
b. Halides or tosylates which are unreactive in ` SN^2` cannot be used .
(I) to (VI) cannot be prepared but (VII) to (IX) can be prepared .
I. It cannot be prepared since `Me_3 C-X` is `3^@` halide.
II. It cannot be prepared since ` Me_3 C-X ` is `3^@` halide and does undergo `SN^(2)` reaction due to steric hindrance .
III. It cannot be prepared since `2^(@)` amine gives poor yield due to elimination.
IV. It cannot be prepared , since arylhalide, is not activated by `EDG` (Me group ) . `ArSN` reaction takes place only when the benzene ring is activated by ` EWG` present at o- and p-ositions .
V. It cannot be prepared , since `EWG (- NO_2`
group ) m-position. `ArSN` reaction does not take place .
VI. It cannot be prepared, since vinyl halides ` (CH_2 = CH - X)` are unreactive in ` SN^2` reactions .
VII. It can be prepared , since henzene ring is activated by ` EQG (-NO_2` group) at p-position and hence ArSN reaction takes place .
VIII. It can be prepared , since bezene ring is activated by ` EWG (-NO_2` group) at o-position and hence ArSN reaction takes place
IX. It can prepared , since allyl halides `(CH_2= CHCH_2 X)` can undergo `SN^2` reaction .