第十一章 含氮化合物

烟碱

N H2

杀虫, 抗生育,毒性大

sp3147 pm

106°

112°

甲胺

sp2

142.5°

苯胺

非平面N.

平面N.

sp3sp2

~125°180°

142.5°

°C

°

The Curtius Rearrangement

RNH2R2NH

In pyridine, the

unshared pair of

electrons on N

is not part of the

aromatic sextet.

Pyridine is a weaker base than heterocyclic

aliphatic amines because the free electron pair on = 1 x 10b

K

b

Contact remains poor even if two liquid phases are used.

The solution is to use phase-catalysis in

Overall Reaction

Mechanism

R ’

R ’

Cope Elimination

+

+

N,N-Dimethyl-hydroxylamine

Methylene cyclohexane

CH 2N-CH 3

CH 3

O -

CH 2

H (CH 3)2NOH 100-150°C

Cope elimination shows syn stereoselectivity but

little or no regioselectivity .

Transition state