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CHAPTER 22 925 
 
 
 
22.23. 
(a) The starting material is an amine, and the reagents indicate a Hofmann elimination. There are two  positions, but 
they are identical because of symmetry. As such, there is only one possible regiochemical outcome for the elimination 
process: 
 
 
(b) The starting material is an amine, and the reagents indicate a Hofmann elimination. There are two  positions, and 
we expect elimination to occur at the  position that leads to the less substituted alkene: 
 
 
 
(c) The starting material is an amine, and the reagents indicate a Hofmann elimination. There are two  positions, and 
we expect elimination to occur at the  position that leads to the less substituted alkene: 
 
 
 
 
22.24. The third product is perhaps the most revealing. It indicates that the structure of PCP must contain an aromatic 
ring for which the benzylic position is connected to a nitrogen atom, and the same benzylic position is also part of a 
cyclohexyl ring. This justifies formation of the first product shown. The second product indicates that the nitrogen 
atom in PCP must be incorporated in a six-membered ring. This ring is opened during formation of the third product. 
 
 
 
 
22.25. 
(a) The starting material is a primary amine, so it is 
converted into the corresponding diazonium salt upon 
treatment with sodium nitrite and HCl: 
 
 
 
(b) The starting material is a secondary amine, so it is 
converted into the corresponding N-nitrosamine upon 
treatment with sodium nitrite and HCl: 
 
 
 
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