Methods of Non-a-Amino Acid Synthesis, 2nd Edition

180

Methods of Non-α-Amino Acid Synthesis, Second Edition

acid 40 (3-amino-5-tert-butylcyclohexanecarboxylic acid)

21

via a modied Schmidt

rearrangement.

22

CO

2

H

CO

2

H

CO

2

H

NH

2

1. H

2

SO

4

, 45°C

CHCl

3

2. NaN

3

3. BaCO

3

39 40

90%

Anhydrides are another class of dicarboxylic acid derivatives as they are typically

prepared from 1,2-dicarboxylic acids. Anhydrides can be synthetically modied

as shown by the reaction of anhydride 41

23

with ammonia to give amide acid 42.

Subsequent Hofmann rearrangement

24

of the amide led to amino acid 43.

25

O

CO

2

H

NH

2

CO

2

H

O

O

O

NH

2

Hofmann

41 42 43

NH

3

Lactones are cyclic esters and obvious acid derivatives, and they are often readily

av